RU2798797C2 - User equipment used in downlink control channel monitoring - Google Patents

Abstract

FIELD: communications.

SUBSTANCE: invention relates to improved monitoring of the downlink control channel. To achieve that a user equipment (UE) is provided, comprising a processing circuit that controls a function that includes monitoring a downlink control channel of an unlicensed radio cell to detect information destined for the UE. An unlicensed radio cell operates on an unlicensed frequency grid and is controlled by a base station. The processing circuit and the receiver monitor the downlink control channel based on a first timer and a second timer operating in parallel. The first timer is used to limit the maximum downlink control channel monitoring time by starting the first timer at the start of monitoring and stopping monitoring after the first timer expires. The second timer is used to stop monitoring earlier than the first timer, depending on the state of occupancy of the unlicensed band by the base station.

EFFECT: improved monitoring of the downlink control channel.

21 cl, 16 dwg

Description

FIELD OF TECHNOLOGY

The present invention relates to methods, apparatuses and articles in communication systems such as 3GPP communication systems.

BACKGROUND OF THE INVENTION

The 3rd Generation Partnership Project (3GPP) is currently working on specifications for next generation cellular technology, also called fifth generation (5G).

One of the objectives is to provide a single technical framework covering all use cases, requirements and deployment scenarios (see e.g. section 6 of TR 38.913 version 15.0.0), at least including enhanced mobile broadband (eMBB), ultra-reliable communication with low latency (URLLC), mass machine type communication (mMTC). For example, eMBV deployment scenarios may include indoor access point, dense urban, rural, large-scale urban, and high-speed communications; URLLC deployment scenarios may include industrial control systems, m-health (remote monitoring, diagnosis and treatment), real-time vehicle control, global monitoring and control systems for smart grids; mMTC deployment scenarios may include scenarios with a large number of non-time critical devices such as smart wearables and sensor networks. The eMBB and URLLC services are similar in that they both require very high bandwidth, but differ in that the URLLC service may preferentially require ultra-low time delays.

The second challenge is to achieve forward compatibility. Backward compatibility with Long Term Evolution (LTE, LTE-A) cellular systems is not required, facilitating completely new system design and/or implementation of new features.

DISCLOSURE OF THE INVENTION

One non-limiting and exemplary embodiment of the invention facilitates the provision of improved procedures for monitoring a downlink control channel.

In one embodiment, the methods disclosed herein characterize a user equipment comprising a processing circuit that, in operation, performs a function that includes monitoring the downlink control channel of an unlicensed radio cell for information intended for user equipment (User Equipment, UE), wherein the unlicensed radio cell operates on an unlicensed frequency band and is controlled by a base station that communicates with the user equipment. The processing circuit and the receiver monitor the downlink control channel based on a first timer and a second timer operating in parallel. The first timer is used to limit the maximum time that monitoring of the downlink control channel must be performed by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring of the downlink control channel after the first timer expires. The second timer is used to stop the monitoring of the downlink control channel before the first timer depending on the busy state of the unlicensed grid channel of the radio cell by the base station.

It should be noted that general or specific embodiments may be implemented as a system, method, integrated circuit, computer program, storage medium, or any selective combination thereof.

Additional useful properties and advantages of the disclosed embodiments, as well as other embodiments, are apparent from the description and drawings. Useful properties and/or advantages can be provided separately by various examples of implementation and features given in the description and shown in the drawings, and in order to provide one or more of these useful properties and/or advantages, it is not necessary to perform all of these implementations or features.

BRIEF DESCRIPTION OF THE DRAWINGS

The following implementation examples are described in more detail with reference to the attached diagrams and drawings.

FIG. 1 shows an exemplary architecture for a 3GPP NR system;

in FIG. 2 shows exemplary user plane and control plane architectures for LTE eNBs, gNBs, and UEs;

in FIG. 3 illustrates the operation of the DRX of the mobile terminal and, in particular, the possibility and duration periods of DRX on corresponding to short and long DRX cycles;

in FIG. 4 illustrates messages exchanged between an eNB and a UE when executing a Random Access Channel (RACH) procedure with contention;

in FIG. 5 illustrates messages exchanged between an eNB and a UE when performing a contention-free RACH procedure;

FIG. 6 illustrates an example LAA scenario with multiple licensed and unlicensed cells;

in FIG. 7 illustrates the transmission behavior for LAA transmission;

in FIG. 8 illustrates an exemplary and simplified structure of UE and gNB;

in FIG. 9 illustrates a UE structure according to an exemplary embodiment of an enhanced downlink control channel monitoring procedure;

in FIG. 10 illustrates the various functions to be performed in the UE and the parallel operation of two timers involved and monitoring of the downlink control channel;

in FIG. 11 is a flowchart of UE operation according to an exemplary embodiment of an enhanced downlink control channel monitoring procedure;

in FIG. 12 is a flowchart of an operation of a UE according to a first exemplary embodiment of an enhanced downlink control channel monitoring procedure;

in FIG. 13 illustrates the parallel operation of the first and second timers and the resulting PDCCH monitoring according to the first exemplary implementation of the improved downlink control channel monitoring procedure described in FIG. 12;

in FIG. 14 is a flow diagram of a UE operation according to a second exemplary embodiment of an enhanced downlink control channel monitoring procedure;

in FIG. 15 illustrates the parallel operation of the first and second timers and the resulting PDCCH monitoring according to the second exemplary implementation of the improved downlink control channel monitoring procedure described in FIG. 14, and

FIG. 16 illustrates the parallel operation of the first and second timers and the resulting PDCCH monitoring according to the second exemplary embodiment of the improved downlink control channel monitoring procedure described in FIG. 14.

IMPLEMENTATION OF THE INVENTION

NR 5G system architecture and protocol stacks

3GPP is working on the next release of ^5th generation cellular technology, simply called 5G, including the development of New Radio (NR.) access technology operating at frequencies up to 100 GHz. The first version of the 5G standard was finalized at the end of 2017, allowing the transition to 5G NR trials in line with the standard and commercial smartphone deployments.

Among other things, the overall architecture of the system assumes a Next Generation - Radio Access Network (NG-RAN), which includes gNBs providing a user plane (access layer/packet data convergence protocol/radio link control protocol access control protocol to the media/physical layer (SDAP/PDCP/RLC/MAC/PHY)) with next generation radio access (NG-radio access) and control plane protocol (RRC) protocol outputs towards the UE. gNB stations are interconnected via the Xn interface. gNBs are also connected via a Next Generation (NG) interface to a Next Generation Core (NGC), more specifically, to an Access and Mobility Management Function (AMF) (e.g., to a specific kernel object executing the AMF) via the NG-C interface and to a User Plane Function (UPF) (eg, a specific kernel object executing the UPF) via the NG-U interface. The NG-RAN architecture is shown in FIG. 1 (see, for example, 3GPP TS 38.300 v15.5.0, section 4).

Various deployment scenarios may be supported (see eg 3GPP TR 38.801 V14.0.0). For example, this document presents a decentralized deployment scenario (see, for example, section 5.2 in TR 38.801; centralized deployment is illustrated in section 5.4) in which base stations supporting 5G NR can be deployed. FIG. 2 illustrates an exemplary decentralized deployment scenario (see, for example, FIG. 5.2.-1 of referenced TR 38.801), while further illustrating the LTE eNB as well as the user equipment (UE) that is connected to both the gNB and to the LTE eNB. The new eNB for NR 5G may be referred to as gNB as an example. eNB eLTE is an evolution of the eNB that supports connectivity to the Evolved Packet Core (EPC) and the Next Generation Core (NGC).

User plane protocol stack for NR (see e.g. 3GPP TS 38.300 v15.5.0 section 4.4.1) includes Packet Data Convergence Protocol (PDCP, see section 6.4 TS 38.300), radio link control (Radio Link Control, RLC, see section 6.3 of TS 38.300) and Medium Access Control (MAC, see section 6.2 of TS 38.300) sublayers that terminate in the gNB on the network side. In addition, a new Access Stratum (AS) Service Data Adaptation Protocol (SDAP) sublayer is introduced over PDCP (see, for example, subclause 6.5 of 3GPP TS 38.300). The control plane protocol stack is also defined for NR (see eg TS 38.300 section 4.4.2). An overview of layer 2 functions is given in subclause 6 of TS 38.300. The functions of the PDCP, RLC, and MAC sublayers are listed in sections 6.4, 6.3, and 6.2 of TS 38.300, respectively. RRC layer functions are listed in subclause 7 of TS 38.300.

For example, the media access control layer manages logical channel multiplexing as well as scheduling and scheduling-related functions, including the management of various numerical data.

For the physical layer, the MAC layer uses services in the form of transport channels. The transport channel can be defined by how and with what characteristics information is transmitted over the air interface. The Random-Access Channel (RACH) is also defined as a MAC controlled transport channel, despite the fact that it does not carry transport blocks. One of the procedures supported by the MAC layer is the random access procedure.

The physical layer (PHY), for example, is responsible for coding, HARQ PHY processing, modulation, multi-antenna processing, and mapping of the signal to the appropriate physical time-frequency resources. It also controls the mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used to transmit a particular transport channel, and each transport channel is mapped to a corresponding physical channel. One physical channel is PRACH (Physical Random Access Channel, Physical Random Access Channel) used for random access.

NR use cases/deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLC), mass machine type communication (mMTC) which have different requirements in terms of data rate, latency and coverage. For example, eMBV is expected to support peak data rates (20 Gbit/s downlink and 10 Gbit/s uplink) and user-experienced data rates up to three times those offered by IMT-Advanced. On the other hand, in the case of URLLC, ultra-low latency (0.5 ms delay for uplink and downlink in the user plane) and high reliability (1-10 ^-5 within 1 ms) are more stringent. Finally, mMTC may preferentially require high communication density (1,000,000 devices per ^km2 in an urban environment), large coverage area in harsh environments, and extremely long battery life for low-cost devices (15 years).

Therefore, OFDM numerical data (eg, subcarrier spacing, OFDM symbol duration, cyclic prefix (CP) duration, number of symbols per scheduling interval) appropriate for one use case may not be sufficiently appropriate for another. For example, low latency services may preferentially require a shorter symbol duration (and hence greater subcarrier spacing) and/or fewer symbols per scheduling interval (also referred to as TTI) compared to an mMTC service. In addition, use cases with large channel delay spreads may preferentially require a longer CP duration compared to scenarios with short delay spreads. The subcarrier spacing should be appropriately optimized to maintain a similar CP overhead. An NR may support more than one subcarrier spacing value. Accordingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, etc. are currently being considered. The symbol duration T _u and the subcarrier spacing Δf are directly related to each other by the formula Δf=1/T _u . Similar to LTE systems, the term "resource element" can be used to refer to the minimum resource unit consisting of one subcarrier for the length of one OFDM/SC-FDMA symbol.

In the new 5G-NR radio system, the resource grid of subcarriers and OFDM symbols for each numerical data and carrier is determined for uplink and downlink, respectively. Each element in the resource grid is called a resource element and is identified based on a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211 V15.5.0).

Downlink Control Channel Monitoring, PDCCH, DCI

Many functions performed by the UE include monitoring the downlink control channel (eg, PDCCH, see 3GP TS 38.300 V15.5.0, section 5.2.3) to receive, for example, specific control information or data intended for the UE.

A partial list of these features is provided below:

• function of monitoring of paging messages,

• the function of obtaining system information,

• signaling monitoring operation for the Discontinued Reception (DRX) function,

• an idle monitoring operation for the Discontinued Reception (DRX) function,

• receiving a random access response for a random access function,

• packet data convergence protocol layer reordering function, PDCP.

In the present description, the focus will be on the above list of functions. However, the concepts and aspects for improving monitoring of the Physical Downlink Control Channel (PDCCH) described in this document are also applicable to other functions that include PDCCH monitoring.

As mentioned above, PDCCH monitoring is performed by the UE so as to identify and receive information intended for the UE, such as control information, as well as user traffic (eg, DCI on the PDCCH and user data on the PDSCH indicated by the PDCCH).

The downlink control information (called downlink control information, DCI) has the same purpose in 5G NR as DCI in LTE, namely, it is a special set of control information that, for example, schedules a downlink data channel. (eg, PDSCH) or an uplink data channel (eg, Physical Uplink Shared CHannel, PUSCH). A number of different DCI formats are already defined in 5G NR (see TS 38.212 v15.5.0 section 7.3.1).

The monitoring of the PDCCH of each of these functions serves a specific purpose and thus starts at the indicated end. PDCCH monitoring is typically controlled at least based on a timer controlled by the UE. The timer is for controlling PDCCH monitoring, eg, limiting the maximum time that the UE must monitor the PDCCH. For example, the UE may not need to perform PDCCH monitoring indefinitely, but may stop monitoring after some time to be able to save power. Accordingly, the timer may be started when the UE starts PDCCH monitoring with the intended target. Then, when the timer expires, the UE may stop monitoring the PDCCH for the intended use and may save power.

The above functions will be described, respectively, in more detail below.

Paging procedures in 5G NR

An exemplary implementation of the 5G NR paging function that includes PDCCH monitoring according to the current standardized version will be described in a simplified and abbreviated form below.

There are two different paging procedures in 5G NR, a RAN based paging procedure (e.g. based on RAN notification areas) and a network core based paging procedure (see e.g. 3GPP TS 38.300 v15.5.0, TS 38.304 v15.3.0 and TS 38.331 v15.5.0 relating to RAN paging and CN paging in several of its sections, such as section 9.2.5 "Paging" in TS 38.300).

Paging allows the network to reach UEs in the RRC_IDLE and RRC_INAKTIVE states via paging messages and notify UEs in the RRC_IDLE, RRC_INAKTIVE and RRC_CONNECTED states of system information changes and ETWS/CMAS (Earthquake and Tsunami Warning System/Commercial Mobile Alert System) messages via short messages. Both paging messages and short messages are addressed with the P-RNTI on the PDCCH to be controlled by the UE. But while the actual paging messages (eg, with page entries) are then sent on the PCCH (as indicated by the PDCCH), the short messages may be sent on the PDCCH directly.

While in RRC_IDLE the UE monitors paging channels for CN-initiated paging, in RRC_INACTIVE the UE also monitors paging channels for RAN-initiated paging. The UE does not need to continuously monitor paging channels; paging DRX is defined when the UE in RRC_IDLE or RRC_INAKTIVE is only required to monitor paging channels for one paging event (PO) per DRX cycle (see 3GPP TS 38.304 V15.3.0, e.g. sections 6.1 and 7.1). DRX paging cycles are network configurable.

The UE POs for CN-initiated and RAN-initiated paging are based on the same UE ID, resulting in overlapping POs for both. The number of different ROs in a DRX cycle may be configured by system information, and the network may allocate UEs to these ROs based on their IDs. The PO is a set of PDCCH monitoring events and may consist of a plurality of time slots (eg, subframe or OFDM symbol) where a DCI paging may be sent. One paging frame (Paging Frame, PF) is one radio frame and may contain one or more POs or a start PO.

While in RRC_CONNECTED, the UE monitors the paging channels in any PO signaled in the system information to indicate a change in SI and notify the Public Warning System (PWS). In the case of bandwidth adaptation (BA) (see clause 6.10 in TS 38.300), the UE in RRC_CONNECTED only monitors the paging channels on the active BWP with the shared search space configured.

Summarizing the above in the context of improved concepts and aspects of PDCCH monitoring, as will be explained below, to control PDCCH monitoring for the paging function, the UE may use a timer, for example, to count the duration of the paging event. For example, a timer starts at the start of PO until the timer (with the length of PO as the value of the timer) expires.

When the UE receives the paging message, the UE may stop monitoring the PDCCH. Depending on the paging reason, the UE may continue, for example, obtaining system information or establishing an RRC connection with the base station and then receiving traffic/command from the network.

Getting information about the NR system

An exemplary implementation of the 5G NR system information acquisition function that includes PDCCH monitoring according to the current standardized version will be described in a simplified and concise manner below.

In 5G NR, System Information (SI) is divided into a Master Information Block (MIB) and several System Information Blocks (SIB) (see 3GPP TS 38.331 V15.5.1, e.g. Section 5.2, see also 3GPP TS 38.300 V15.5.0, eg Section 7.3, and 3GPP TS 38.213, eg Section 13). The MIB is transmitted over the BCH and includes the parameters needed to receive SIB1 from the cell. SIB1 is periodically transmitted on the DL-SCH and includes information relating to availability and scheduling, such as mapping SIB messages to SI messages, periodicity, SI window size of other SIBs, indicating whether one or more SIBs are provided on demand only, and in in this case, the configuration required by the UE to fulfill the SI request.

SIBs other than SIB1 are carried in system information messages (SI messages) that are transmitted on the DL-SCH. SIBs having the same periodicity may be mapped with the same SI message. Each SI message is transmitted in periodically occurring time domain windows (called SI windows with the same length for all SI messages). Each SI message is associated with an SI window, and the SI windows of different SI messages do not overlap.

The UE applies the SI acquisition procedure to obtain access stratum (Access Stratum, AS) and non-access stratum (Non-Access stratum, NAS) information, and is applied to the UE in RRC_IDLE, RRC_INAKTIVE, and RRC_CONNECTED modes. For example, the UE may apply the SI acquisition procedure upon cell selection (e.g., on power-up), cell reselection, returning from an uncovered area, after reconfiguration with synchronization completion, after entering the network from another radio access technology (Radio Access Technology, RAT) after receiving an indication that the system information has changed, and when the UE does not have a valid version of the stored SIB. The modification period is used, i.e. the updated SI is broadcast in the modification period following the SI change indication transmission period.

The UE receives SI modification messages using a short message sent with P-RNTI via DCI. UEs in RRC_IDLE or RRC_INACTIVE may monitor the SI change indication in case of their own paging event every DRX cycle (see above). UEs in RRC_CONNECTED shall monitor the SI change indication on any paging event at least once per modification period.

To receive an SI message, one or more PDCCH monitoring events are defined, which may be the same or different than for PDCCH monitoring SIB1. For example, the UE assumes that in the SI window a PDCCH for an SI message is transmitted in at least one PDCCH monitoring event corresponding to each SSB (sync signal block) transmitted. The SIB1 configuration provides information about the search space and other PDCCH related parameters that the UE needs to monitor for SIB1 scheduling.

Summarizing the above in the context of improved concepts and aspects for PDCCH monitoring, as will be explained below, the UE may use a timer to control the length of the SI window, and the UE may monitor the PDCCH until it successfully receives an SI message, or until the end of the SI window. with a specific length. If no SI message has been received by the end of the SI window, PDCCH monitoring may be retried at the next SI window event for the corresponding SI message in the current modification period.

Intermittent reception, DRX, in LTE and 5G NR

An exemplary implementation of the Discontinuous Reception (DRX) function in 5G NR, which includes PDCCH monitoring, according to the current standardized version, will be explained in a simplified and abbreviated form below.

To reduce battery usage, the UE employs a mechanism to minimize the time spent by the UE monitoring the PDCCH, which is called Discontinuous Reception (DRX) function. The DRX function can be configured for RRC_IDLE, in which case the UE uses either a specific DRX value or a default DRX value (defaultPagingCycle); the default value is carried in the system information and can be 32, 64, 128 and 256 radio frames. The UE needs to wake up for one paging event per DRX cycle, where the paging event is one subframe. The DRX functionality can also be configured for "RRC_CONNECTED" by the UE so that it does not always need to monitor downlink control channels to detect downlink control information (or more simply: the UE monitors the PDCCH) (see 3GPP Technical Standard TS 36.321 , 15.5.0, chapter 5.7).

The following options are available to define the DRX behavior of the UE; those. periods of activity when the mobile node is active (ie, during DRX activity), and periods when the mobile node is in DRX (ie, not during DRX activity).

On Duration: Duration in downlink subframes, ie, more specifically, PDCCH subframes (also referred to as PDCCH subframes), when the user equipment, upon waking up from DRX, receives and monitors the PDCCH. It should be noted here that the term "PDCCH" refers to a PDCCH, an EPDCCH (in subframes when configured), or an R-PDCCH for a relay node with an R-PDCCH configured and not suspended. If the user equipment successfully decodes the PDCCH, the user equipment remains awake/awake and starts the sleep timer; [1-200 subframes; 16 steps: 1-6, 10-60, 80, 100, 200]

DRX idle timer: duration in downlink subframes that the user equipment has been waiting for a successful PDCCH decoding since the last successful PDCCH decoding; when the UE cannot decode the PDCCH during this period, it reintroduces DRX. The user equipment shall restart the sleep timer after one successful PDCCH decoding for the first transmission only (ie not for retransmissions). [1-2560 subframes; 22 steps, 10 doubles: 1-6, 8, 10-60, 80, 100-300, 500, 750, 1280, 1920, 2560]

DRX retransmission timer: defines the number of consecutive PDCCH subframes in which the UE waits for downlink retransmission after the first available retransmission time. [1-33 subframes, 8 steps: 1, 2, 4, 6, 8, 16, 24, 33]

DRX Short Cycle: Defines the periodic repetition of the on duration followed by a possible period of inactivity for a short DRX cycle. This parameter is optional. [2-640 subframes; 16 steps: 2, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 256, 320, 512, 640]

DRX short cycle timer: defines the number of consecutive subframes in which the UE follows a short DRX cycle after the DRX idle timer expires. This parameter is optional. [1-16 subframes]

DRX Long Cycle Start Offset: defines the periodic repetition of the on duration followed by a possible period of inactivity for the long DRX cycle, as well as the offset in subframes at the start of the on duration (defined by the formula defined in TS 36.321 section 5.7); [cycle length 10-2560 subframes; 16 steps: 10, 20, 30, 32, 40, 64, 80, 128, 160, 256, 320, 512, 640, 1024, 1280, 2048, 2560; offset is an integer between 0 and the subframe length of the selected cycle]

The total wakefulness of the UE is referred to as "awake time" or DRX active time. The activity time, for example, includes the duration of the DRX cycle on, the time that the UE performs continuous reception while the idle timer has not expired, and the time that the UE performs continuous reception while waiting for downlink retransmission after one HARQ RTT. Similarly, for uplink, the UE is in the awake state (i.e., during DRX activity time) in subframes in which uplink retransmission grants can be received on the PDCCH, i.e. every 8 ms after the initial uplink transmission until the maximum number of retransmissions is reached. Based on the above, the minimum activity time has a fixed duration equal to the duration of the inclusion, and the maximum varies depending on, for example, the activity of the PDCCH.

"DRX Period" or "DRX Off Period" is the duration of downlink subframes during which the UE may skip receiving downlink channels in order to conserve battery power, i. it is not required to monitor the downlink channels. DRX operation allows the mobile terminal to repeatedly turn off the radio circuits (according to the currently active DRX cycle) to save power. Whether the UE actually remains in DRX (ie, not active) during the DRX period may be decided by the UE; for example, the UE typically performs inter-frequency measurements that cannot be taken during the on-duration, and thus must be done at other times, such as during DRX off.

To meet conflicting requirements, two DRX cycles, a short cycle and a long cycle, can be configured for each UE; short DRX cycle is optional, i.e. only a long DRX cycle can be used. The transition between short DRX cycle, long DRX cycle and continuous reception is controlled either by a timer or by direct commands from the eNodeB. In a sense, the short DRX cycle can be considered as an acknowledgment period in case a late packet arrives before the UE enters the long DRX cycle. If data arrives at the eNodeB while the UE is in a short DRX cycle, data is scheduled for transmission at the next on-duration time, and the UE then resumes continuous reception. On the other hand, if no data arrives at the eNodeB during the short DRX cycle, the UE enters the long DRX cycle, assuming that the burst activity has now ended.

During the activity time period, the UE monitors the PDCCH, reports the SRS (Sounding Reference Signal) as configured, and reports the CQI (Channel Quality Information)/PMI (Precoding Matrix Indicator)/RI (Rank Indicator)/PTI (Precoding Type Indication) on PUCCH. When the UE is not in active time, Type 0 triggered SRS and CQI/PMI/RI/PTI on PUCCH may not be transmitted. If the UE is configured with CQI masking, the reporting of CQI/PMI/RI/PTI on the PUCCH is limited to activity subframes.

FIG. 3 shows an example of DRX operation. The UE checks scheduling messages (these may also be referred to as downlink/uplink assignment; for example, indicated by its Cellular Radio Network Temporary Identification (C-RNTI) on the PDCCH) for a "duration on" period, which is the same for a long DRX cycle and short DRX cycle.When a scheduling message is received during the "on duration period", the UE starts the "idle timer" and continues to monitor the PDCCH in each subframe while the idle timer is running.During this period, the UE may be considered to be in the "continuous reception mode". Whenever a scheduling message is received while the sleep timer is running, the UE restarts the sleep timer, and when it expires, the UE enters the short DRX cycle and starts the "DRX short cycle timer" (provided that the short DRX cycle is configured). The UE enters a long DRX cycle A short DRX cycle can also be initiated by a DRX MAC control element, which the eNB can send at any time to immediately place the UE in a DRX cycle, i.e. in short DRX cycle (if configured) or long DRX cycle (in case short DRX cycle is not configured).

The basic DRX concepts described above for LTE, with some differences, also apply to the new NR 5G. Standardization has advanced and defined DRX (see 3GPP TS 38.321 V15.5.0, section 5.7 titled Discontinuous Reception (DRX)).

The following is mentioned in TS 38.321:

The RRC controls the operation of the DRX by configuring the following parameters:

- drx-onDurationTimer: duration at start of DRX cycle;

- drx-SlotOffset: delay before starting drx-onDurationTimer;

- drx-StartOffset: subframe where the DRX cycle starts;

- drx-InactivityTimer: duration after a PDCCH event in which the PDCCH indicates a new UL or DL transmission for the MAC entity;

- drx-RetransmissionTimerDL (per DL HARQ process): maximum duration until a DL retransmission is received;

- drx-RetransmissionTimerUL (per UL HARQ process): maximum duration until a UL retransmission is granted;

- drx-LongCycle: DRX long cycle;

- drx-ShortCycle (optional): DRX short cycle;

- drx-ShortCycleTimer (optional): duration for which the UE should monitor the short DRX cycle;

- drx-HARQ-RTT-TimerDL (according to the DL HARQ process): the minimum time a MAC entity waits before assigning a Dl-for HARQ retransmission;

- drx-HARQ-RTT-TimerUL (according to the UL HARQ process): The minimum time a MAC entity waits before allowing a UL HARQ retransmission.

When a DRX cycle is configured, the active time includes the time during which:

- drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or ra-ContentionResolutionTimer works (as described in subclause 5.1.5); or

- a scheduling request has been sent on the PUCCH and is awaiting processing (as described in clause 5.4.4); or

- PDCCH indicating that a new transmission addressed to the C-RNTI of the MAC entity was not received after successfully receiving a random access response for a random access preamble not selected by the MAC entity between a contention-based random access preamble (as described in subclause 5.1.4 TS 38.321).

It should be noted that the term PDCCH may, for example, refer to a common search space PDCCH or a UE-specific search space PDCCH, or even a Group Common PDCCH (GC-PDCCH) in 5G NR.

Of this, it is obvious that DRX for 5G NR also determines the turn-on duration at the beginning of the DRX cycle based on the DRX long cycle and DRX short cycle, and on the transition between them, based on the DRX short cycle timer; the DRX sleep timer determines the duration of continuous reception after receiving the PDCCH, after which the UE enters the sleep mode. Thus, the 5G-NR DRX mechanism conceptually works as shown in FIG. 3.

Summarizing the above in the context of improved concepts and aspects for PDCCH monitoring, as will be explained below, the UE performs PDCCH monitoring using timers to respectively manage the on duration time as well as the DRX idle time. While the appropriate timers are running, the UE must continue to monitor the PDCCH for DRX to work.

Random Access Channel Procedure

An exemplary implementation of the 5G NR random access function that includes PDCCH monitoring according to the current standardized version will be described in a simplified and abbreviated form below.

After the UE has discovered the cell, it can access the cell. This can be done using a random access procedure. The LTE RACH procedure will be described in more detail below with reference to FIG. 4 and 5. A mobile terminal in LTE can only be scheduled for uplink transmission if its uplink transmission is time synchronized. Thus, the random access channel (RACH) procedure plays an important role as an interface between non-synchronized mobile terminals (UEs) and uplink orthogonal radio access transmission. For example, random access in LTE is used to achieve uplink time synchronization for user equipment that has either not yet established or lost its uplink synchronization. Once the user equipment reaches uplink synchronization, the eNodeB may schedule uplink transmission resources for it. One scenario related to random access is that a user equipment in the RRC_CONNECTED state moving from its current serving cell to a new target cell performs a random access procedure to achieve uplink time synchronization in the target cell.

LTE offers two types of random access procedures, allowing access either on a competitive basis, i.e. implying an inherent risk of conflict, or without competition (on a non-competitive basis) (see 3GPP TS 36.321, section 5.1, v15.5.0).

Next, the contention-based LTE random access procedure is described in more detail with reference to FIG. 4. This procedure consists of four "steps". First, the user equipment transmits a random access preamble on the physical random access channel (PRACH) of the eNodeB (ie, message 1 of the RACH procedure). After the eNodeB detects the RACH preamble, it sends a Random Access Response (RAR) message (RACH procedure message 2) on the Physical Downlink Shared Channel (PDSCH) addressed to the Physical Control Channel downlink (Physical Downlink Control Channel, PDCCH) with a random access radio network temporary identifier (Random Access-Radio Network Temporary Identifier, RA-RNTI) identifying the frequency-time interval in which the preamble was detected. If different user equipments transmit the same RACH preamble on the same PRACH resource, also called a collision, they will receive the same random access response message. The RAR message may convey a detected RACH preamble, a timing alignment command (TA command) for synchronizing subsequent uplink transmissions, an assignment (allowance) of an initial uplink resource for the transmission of the first scheduled transmission, and assignment of a Temporary Cellular Radio Network (Temporary) Cell Radio Network Temporary Identifier, T-CRNTI). This T-CRNTI is used by the eNodeB to refer to the mobile device(s) whose RACH preamble has been detected until the RACH procedure is completed, because at that point the eNodeB does not yet know the "real" mobile device identifier.

The user equipment monitors the PDCCH to receive a random access response message within a given time window (eg, called the RAR time window) that is configured by the eNodeB. In response to the RAR message received from the eNodeB, the user equipment transmits the first scheduled uplink transmission on the radio resources assigned by the grant within the random access response. This scheduled uplink transmission transmits an actual random access procedure message, such as an RRC connection request, an RRC resume request, or a buffer status report, for example.

FIG. 5 illustrates the contention-free 3GPP LTE random access procedure, which is simplified compared to the contention-free random access procedure. ENodeB first provides the user equipment with the preamble used for random access, so that there is no risk of collisions, i.e. a plurality of user equipments transmits the same preamble. Accordingly, the user equipment subsequently sends the preamble that was transmitted by the eNodeB to the uplink on the PRACH resource. Since the case where multiple UEs send the same preamble is excluded for contention-free random access, essentially, the contention-free random access procedure ends after the UE successfully receives the random access response.

The same or the same RACH procedure as just described with reference to FIG. 4 and 5 is implemented for the new 5G radio technology (see 38.321 V15.5.0 section 5.1).

In addition, 3GPP is also studying a two-stage RACH procedure for 5G NR in which message 1 corresponding to messages 1 and 3 in the four-stage RACH procedure is transmitted first. The gNB will then respond with message 2 corresponding to messages 2 and 4 of the LTE RACH procedure. Due to the reduced messaging, the delay of the two-stage RACH procedure can be reduced compared to the four-stage RACH procedure. The radio resources for messages are further configured by the network.

Summarizing the above in the context of improved concepts and aspects for PDCCH monitoring, as will be explained below, the UE performs PDCCH monitoring with a timer to control the random access response time window after transmitting the RACH preamble as a first step of the RACH procedure. When the timer expires and no RAR is received, the UE is not required to continue monitoring the PDCCH, but it may, for example, retransmit the RACH preamble. When a RAR is received in the RAR time window, the UE proceeds to the next step of the RACH procedure, such as scheduled user data transmission.

PDCP reordering

An exemplary implementation of the PDCP reordering function in 5G NR, which includes PDCCH monitoring, according to the current standardized version, will be described in a simplified and abbreviated form below (see 3GPP TS 38.323 V15.5.0, e.g. sections 5.1.2, 5.2.1 , 5.2.2).

The Packet Data Convergence Protocol (PDCP) performs compression, encryption, and integrity protection of IP headers. It also handles retransmissions, serial delivery, and removal of duplicates in case of transmission. In particular, the PDCP may be responsible for performing reordering to ensure serial transmission of Service Data Units (SDUs) (also called packets) to higher layer protocols. Reordering basically buffers the received SDU and does not forward it to higher layers until all lower numbered SDUs have been delivered. The counter value is used to identify lost SDUs and request retransmission, as well as to reorder received SDUs before delivery to upper layers.

A timer (eg, called t-reorder) may be used to control the PDCP layer reordering function. This timer is started when an inconsistent transmission from a base station is detected and controls the amount of time the UE can wait for a serial data packet (SDU) transmission before proceeding further. During the operation of the t-reorder timer, the UE may monitor the PDCCH for serial transmission of a data packet (eg, PDCP PDU). When such a data packet is received, the UE may continue PDCP operation, eg, deliver successive SDUs to a higher layer, and stop the t-reorder timer until an inconsistent transmission is next detected.

License Assisted Access (LAA) and Enhanced LAA (eLAA)

The reason for the expansion of LTE to unlicensed frequency bands is the ever-increasing demand for wireless broadband data, combined with a limited number of licensed frequency bands. Therefore, the unlicensed frequency grid is increasingly being considered by cellular operators as an additional tool to expand their service offering. The advantage of LTE in unlicensed bands over other radio access technologies (RATs) such as Wi-Fi is that complementing the LTE platform with access to a licensed frequency grid allows operators and providers to leverage existing or planned equipment investments. LTE/EPC in radio and core network.

However, it must be taken into account that access to an unlicensed frequency grid can never match the quality of access to a licensed frequency grid due to the inevitable coexistence with other radio access technologies (RATs) in the unlicensed frequency grid, such as Wi-Fi. Therefore, LTE operation on the unlicensed bands, at least initially, was considered in addition to LTE operation on the licensed frequency grid, and not a separate operation on the unlicensed frequency grid. Based on this assumption, 3GPP introduced the term Licensed Assisted Access (LAA) for LTE operation on unlicensed frequency bands in combination with at least one licensed frequency band.

Future standalone operation of LTE on an unlicensed frequency grid, i.e. without the help of licensed cells, however, should not be ruled out, and such offline unlicensed operation is now provided for 5G NR.

The current general LAA approach in 3GPP is to use as much as possible the already specified Rel-12 carrier aggregation (CA) frame, where the CA frame configuration, as explained earlier, contains the so-called primary cell carrier (PCell ) and one or more secondary cell (SCell) carriers. In general, the CA supports both self-scheduling of cells (scheduling information and user data are transmitted on the same component carrier) and inter-cell scheduling between cells (scheduling information in terms of PDCCH/EPDCCH and user data in terms of PDSCH/PUSCH are transmitted on different component carriers). bearing).

The use of unlicensed bands has also become a critical target for the development of new 5G-NR. The licensed NR design can be used as a basis and the following deployment scenarios can be considered:

• Media aggregation between an NR licensed cell (eg, PCell) and a non-NR licensed cell (eg, SCell), similar to LTE LAA;

• Dual connection (with LTE and with NR); ENU-DC, in which the main eNB operates on a licensed frequency grid and the secondary gNB operates on an unlicensed frequency grid; NNU-DC, in which the main NB operates on a licensed frequency grid and the secondary gNB operates on an unlicensed frequency grid.

• Stand-Alone (SA): - NR-U SA, in which a stand-alone NR PCell operates on an unlicensed frequency grid;

• - NR cell with downlink in the unlicensed band and UL in the licensed band.

In NR, pre-talk listening must be done on unlicensed media. In particular, transmitting entities perform LBT and channel occupation is allowed only after a successful Clear Channel Assessment (CCA) LBT.

FIG. 6 illustrates a very simple scenario with a licensed PCell, a licensed SCell 1, and various unlicensed SCells 2, 3, and 4 (illustratively shown as small cells). The transmit/receive network nodes of the unlicensed SCells 2, 3 and 4 may be remote radio heads managed by the eNB, or may be nodes connected to the network but not managed by the eNB. For simplicity, the connection of these nodes to the eNB or to the network is not explicitly shown in the figure. In addition, unlicensed radio cell 5 illustrates a separate NR PCell scenario that operates on an unlicensed frequency grid.

One of the most important issues is coexistence with other systems such as Wi-Fi (IEEE 802.11) systems operating in these unlicensed bands. To support fair coexistence between LTE, 5G NR, and other technologies such as Wi-Fi, and to ensure fairness between different operators in the same unlicensed band, channel access for unlicensed bands must comply with certain sets of regulatory rules, which are partly may depend on the geographic region and specific frequency band (see, for example, 3GPP Technical Report TR 36.889, version 13.0.0). Depending on region and band, regulatory requirements to be taken into account when designing LAA and 5G NR procedures include Dynamic Frequency Selection (DFS), Transmit Power Control (TPC), Listen Before Talk (Listen Before Talk, LBT) and discontinuous transmission with a limited maximum transmission duration (may also be called channel busy time or channel allocation time or similar expressions). It is possible to focus on a single global structure, which basically means that all the requirements for different regions and frequency bands at 5 GHz can be taken into account when designing a system.

The Listen-Before-Talk (LBT) procedure is defined as the mechanism by which a device applies a Clear Channel Assessment (CCA) check before using a channel. According to one exemplary implementation, the CCA uses at least energy detection to determine the presence or absence of other signals on an unlicensed channel to determine if the channel is busy or free, respectively. European and Japanese regulations, for example, mandate the use of LBT in unlicensed bands. In addition to regulatory requirements, this LBT carrier sounding is one way to distribute the unlicensed frequency grid fairly and thus is considered a vital feature for fair and friendly operation in the unlicensed frequency grid in a single global solution system.

In an unlicensed frequency grid, channel availability cannot always be guaranteed. In addition, some regions, such as Europe and Japan, prohibit continuous transmission and set limits on the maximum transmission duration on an unlicensed frequency grid (maximum channel capacity). Therefore, discontinuous transmission with a limited maximum transmission duration is a feature for LAA and 5G NR.

In accordance with this European regulation regarding LBT, devices must perform channel idle detection (Clear Channel Assessment, CCA) before occupying an unlicensed radio channel with data transmission. In such limited exemplary scenarios, it is allowed to initiate a transmission on an unlicensed channel only after the channel is found to be free, based on, for example, energy detection. In particular, the equipment must observe the channel for a certain minimum time (eg for Europe 20 µs, see ETSI 301 893 clause 4.8.3) during the CCA. The channel is considered busy if the detected energy level exceeds the configured CCA threshold (for example, for Europe -73 dBm/MHz, see ETSI 301 893 clause 4.8.3), and vice versa is considered free if the detected power level is below the configured threshold. SSA values. If a channel is determined to be busy, it shall not transmit on that channel for the next fixed frame period. If the channel is classified as free, the equipment can transmit immediately. The maximum transmission duration is limited to ensure a fair distribution of resources with other devices operating in the same frequency band.

The SCA may be performed multiple times, optionally with a countdown time interval.

In addition, the total time that equipment has transmissions on a given carrier without reassessing the availability of that carrier (i.e. LBT/CCA) is defined as the channel busy time (see e.g. ETSI 301 893 clause 4.8.3.1) . The channel fill time should be in the range of 1 ms to 10 ms, where the maximum channel busy time could be, for example, 4 ms, as currently defined for Europe. In addition, there is a minimum latency when the UE is not allowed to transmit after transmitting on an unlicensed cell, wherein the minimum latency is at least 5% of the channel busy time. By the end of the sleep period, the UE may perform a new CCA, and so on.

In addition, the CCA may not be required for a certain period of time after the signal is received by another object, for example, within 16 microseconds within the overall COT. For example, switching between DL and UL, and between UL and DL within a common gNB COT does not require LBT.

This transmission behavior is schematically illustrated in FIG. 7 (see, for example, ETSI EN 301 893).

Therefore, operation on unlicensed radio cells requires any transmitter to listen before speaking, as described above. This also applies to the transmission of the PDCCH by the base station and, as a result, may also affect the monitoring of the PDCCH by the user equipment.

Many different functions performed by the UE (see examples above) include PDCCH monitoring and thus may be affected by LBT failures of a gNB receiving an unlicensed cell (also expressed: receiving an unlicensed frequency grid of an unlicensed radio cell).

One possible solution to compensate for these LBT failures by the gNB for scenarios where the radio cell operates on an unlicensed frequency grid is to extend the appropriate time during which the PDCCH is monitored, for example, compared to licensed radio cell operation. Thus, the probability is increased that the gNB successfully obtains the unlicensed frequency grid and thus reaches the UE for, for example, PDCCH and/or possibly PDSCH transmission.

For example, to add more capability for the gNB to communicate system information, it may be possible to configure a longer SI window for NR to operate without a license. In addition, to account for possible LBT failures, the DRX on time can be configured to be extended. Reduced paging opportunities caused by LBT failures can be compensated for by increasing the duration of the paging event or increasing the number of paging events. As a further example, the RAR window size can be increased to 20 ms, for example. Configuring a longer PDCCH monitoring time window to compensate for LBT failures on the gNB side can be a simple solution, making maximum use of existing functions, thus having little to no impact on any of the 3GPP specifications.

However, simply configuring a longer PDCCH monitoring duration (eg, static/semi-static) may also result in increased power consumption by the UE, since the UE has to monitor the PDCCH for a longer time. This energy disadvantage can especially manifest itself when the channel is not busy. In particular, assuming that the unlicensed frequency grid is not blocked by another entity, the gNB would soon be able to send PDCCH (and possibly PDSCH), but if the gNB still does not call UE, UE monitors PDCCH for a longer time without any benefit.

As a result, the inventors have determined that it is possible to improve PDCCH monitoring for one or more of the above functions (eg, DRX, paging, system information, random access, PDCP reordering) when operating on an unlicensed frequency grid. The invention can also be applied to other functions that include PDCCH monitoring not explicitly mentioned above.

In the following, UEs, base stations, and procedures to meet these needs will be described mainly for the new radio access technology envisaged for 5G mobile communication systems, but which can also be used in LTE mobile communication systems. Various implementations and options will also be explained. The following disclosure is facilitated by the discussion and results described in the foregoing description and may be based on at least part of it and may be implemented in such systems.

In general, it should be noted that a number of assumptions are made in the present description to enable the principles underlying the present invention to be explained in a clear and understandable manner. However, these assumptions should be understood only as examples given in the present description for illustrative purposes, and they should not limit the scope of the invention. The specialist will be clear that the principles of the following description and the principles set forth in the claims can be applied to various scenarios and ways that are not explicitly described in this document.

In addition, some of the terms used for procedures, elements, layers, etc. used hereinafter are closely related to LTE/LTE-A systems or terminology used in the current 3GPP 5G standardization, even though that the specific terminology to be used in the context of the new radio access technology for the following 3GPP 5G communication systems is not yet fully defined or may change definitively. Thus, the terminology may be changed in the future without affecting the operation of the embodiments of the invention. Therefore, one skilled in the art should be aware that the embodiments and the scope of their protection should not be limited to the specific terms used as an example in this document due to the lack of newer or definitively agreed terminology, but should be more broadly understood from the point of view view of the functions and concepts underlying the operation and principles of the present invention.

For example, a mobile station or a mobile node or a user terminal or user equipment (UE) is a physical entity in a communication network. One node can have several functional objects. A functional entity refers to a software or hardware module that implements and/or offers a predefined set of functions to other functional entities of a specified or other node or network. The nodes may have one or more interfaces that connect the node to a communication medium or medium over which the nodes can communicate. Likewise, a network entity may have a logical interface connecting the functional entity to a communication medium or medium over which it can communicate with other functional entities or associated nodes.

The term "base station" or "radio base station" in this document refers to a physical entity in a communication network. Similar to a mobile station, a base station may have multiple functional entities. A functional entity refers to a software or hardware module that implements and/or offers a predefined set of functions to other functional entities of a specified or other node or network. The physical entity performs some control tasks with respect to the communications device, including one or more of the scheduling and configuring elements. It should be noted that the functionality of the base station and the functionality of the communication device can also be combined in one device. For example, a mobile terminal may also implement base station functionality for other terminals. In the terminology used in LTE NR., this is an eNB (or eNodeB), while in the terminology currently used for 5G NR, this is a gNB.

FIG. 8 is a general, simplified, exemplary block diagram of a user equipment (also referred to as a communication device) and a scheduling device (which in this case, for example, is assumed to be located in a base station, for example, an eLTE eNB (alternatively referred to as ng-eNB), or gNB in 5G NR, the UE and the eNB/gNB communicate with each other over a (wireless) physical channel, respectively, using a transceiver.

The communication device may include a transceiver and processing circuitry. The transceiver, in turn, may contain a receiver and transmitter, and/or function as a receiver and transmitter. The processing circuit may be one or more hardware components, such as one or more processors, or any LSI (Large Scale Integration, large integrated circuit). Between the transceiver and the processing circuit there is an input/output point (or node) through which the processing circuit can control the transceiver during operation, i.e. control the receiver and/or transmitter and exchange receive/transmit data. The transceiver for the transmitter and receiver may include radio frequency (RF) input circuitry including one or more antennas, amplifiers, RF modulators/demodulators, and the like. The processing circuit may implement control tasks such as controlling a transceiver to transmit user data and control data provided by the processing circuit and/or receive user data and control data that is further processed by the processing circuit. The processing circuit may also perform other processes such as determination, decision, calculation, measurement, and the like. The transmitter may perform the transmission process and other processes related thereto. The receiver may perform the receive process and other related processes such as channel monitoring.

Enhanced downlink control channel (eg, PDCCH) monitoring is described below.

The solutions proposed in the description below will be described primarily in the context of unlicensed 5G NR scenarios, but may also be applicable to unlicensed operation in LTE (A). As explained above with reference to FIG. 6, the UE may be located in an unlicensed radio cell managed by a gNB (eg, one of the unlicensed SCells in FIG. 6 or a separate unlicensed radio cell). The UE is configured to perform a variety of functions, also including functions that include monitoring a downlink control channel transmitted by a gNB in an unlicensed radio cell (using an unlicensed frequency grid). Briefly, a downlink control channel may be used by a gNB to transmit downlink control information (eg, downlink or uplink transmission scheduling on the respective downlink/uplink shared channel) and user data.

FIG. 9 shows a simplified and exemplary UE structure according to an exemplary enhanced downlink control channel monitoring solution that can be implemented based on the general UE structure disclosed above with reference to FIG. 8. The various structural elements of the UE shown in this figure may be interconnected, for example, by respective I/O nodes (not shown), for example, to exchange control and user data and other signals. The UE may contain additional structural elements, although they are not shown for illustrative purposes. Based on the foregoing, it is clear that the UE may comprise a function operation scheme, a downlink control channel monitoring scheme, a scheme for parallel operation of the first and second timer, and a channel busy detection scheme.

In this case, as will become apparent from the following description, the processing circuit may thus, by way of example, be configured to at least partially perform one or more operational functions, monitor the downlink control channel, and operate the first and second timers. . Thus, the receiver may be exemplarily configured to at least partially perform one or more of the following: monitoring the downlink control channel and receiving information intended for the UE on the downlink control channel.

FIG. 10 is a schematic illustration of various functions that can be controlled by the UE. As is obvious, the UE may control several different functions #1 to #N, such as the functions mentioned above. For example, functions #1 through #N might be:

• function of monitoring of paging messages,

• the function of collecting information about the system,

• alarm monitoring operation for DRX function,

• idle monitoring operation for the DRX function,

• receiving a random access response for the random access function, and

• PDCP layer reordering function.

Each of the functions performed includes parallel operation of the first and second timers, as well as monitoring of the downlink control channel. The respective first and second timers typically differ between different functions, eg have different timer values, as well as different purposes, as will become apparent in the following.

The concepts and aspects of the improved downlink control channel monitoring procedure will first be explained independently of the other function, with emphasis on general aspects that help overcome the problems of the prior art.

FIG. 11 is a flow diagram of an exemplary UE according to this enhanced downlink control channel monitoring procedure. As can be seen from it, it is assumed that the UE performs a function that includes monitoring the downlink control channel of an unlicensed radio cell. The monitoring of the downlink control channel is performed based on the first timer and the second timer, which operate in parallel, for example, when the monitoring of the downlink control channel is stopped, it can be controlled using two timers.

Accordingly, the first timer is used to limit the maximum time that the UE must monitor the downlink control channel. To this end, the first timer is started when the UE starts monitoring the downlink control channel according to the function being performed, and then the monitoring is stopped no later than the expiration of the first timer. This first timer is configured and operates regardless of the busy state of the unlicensed frequency grid channel. In one optional implementation, the first timer may be a timer used in the prior art to control monitoring of a downlink control channel for a managed function (e.g., a paging event timer for a paging function or an activity timer for a DRX function, or a timer for a system receive window). information, or the idle timer for the DRX function, or the timer for the RAR window, or the PDCP reorder timer). The timer value for the first timer may, for example, be increased for the unlicensed scenario compared to the licensed scenario (see above discussion of the simple solution and the resulting disadvantage).

On the other hand, a second timer should be used in order to be able to stop monitoring the downlink control channel before the first timer, depending on the busy state of the unlicensed grid channel of the radio cell. In other words, the purpose of the second timer is to reduce the time that the UE monitors the downlink control channel, where possible or appropriate, based on the busy state of the unlicensed gNB channel. For example, the busy state of the channel is taken into account for how to use the second timer to stop monitoring, such that when the gNB is able to occupy the channel but still does not send information (e.g., control information or data) to the UE, monitoring may be stopped earlier. This follows from the notion that the gNB does not have difficulty reaching the UE due to any LBT failure, but rather the gNB does not feel the need or cannot reach the UE for some other reason (which may not be related to the LBT). Therefore, the second timer is intended to compensate for LBT failures, and not other reasons why the gNB does not reach the UE, by allowing the UE to stop monitoring the channel before the first timer, depending on the busy state of the channel.

This second timer is controlled by the UE in parallel, eg not one timer after another timer. Monitoring of the function specific downlink control channel may be stopped based on either the first or second timer. Thus, running two timers in parallel to control the monitoring stop time provides the benefit of stopping monitoring earlier when possible based on the second timer and channel busy state, while maximizing downlink control channel monitoring time by using the first timer. Thus, the energy used to monitor the downlink control channel can be reduced in some cases.

Accordingly, while the downlink control channel monitoring for a specific function is based on the first timer when operating in a licensed radio cell, the downlink control channel monitoring for this specific function is based on the first and second timers when operating in an unlicensed radio cell.

One possible exemplary implementation for ensuring that the second timer expires before the first timer is to configure a smaller timer value for the second timer than for the first timer. The smaller the second timer compared to the first timer, the more power saving effect the UE can obtain. However, the gNB will have less time to reach the UE according to the function (e.g. paging the UE in a timely manner, etc.)

Returning to the block diagram of FIG. 11, the UE controls the first timer and the second timer in parallel to control the downlink control channel monitoring stop time. As shown in FIG. 11, the improved monitoring procedure includes determining the unlicensed grid channel busy state to use a second timer to stop monitoring while the first timer runs regardless of the unlicensed grid channel busy state. The second timer is then used to control whether it is advisable to stop monitoring the downlink control channel earlier than the first timer. Whether or not to stop monitoring early depends on the occupancy state of the unlicensed grid channel at the time of monitoring the downlink control channel.

As stated above, monitoring of the downlink control channel is performed as part of the managed function and thus is very specific to the managed function. The function itself may even define some function-specific conditions when to start and when to stop monitoring the downlink control channel. For example, monitoring may also be terminated upon receipt of information intended for the UE, in accordance with the purpose of the controlled function.

For example, the paging function-specific monitoring of the downlink control channel is also stopped when a paging message is received. In other words, the paging function requires the UE to monitor the downlink control channel during the paging event in order to be able to receive the paging message. In this particular function, monitoring of the downlink control channel is stopped not only based on the operation of the first and second timers, but also upon receipt of a page message. According to another function, monitoring of the downlink control channel is performed to detect inactivity of the DRX function, wherein the monitoring of the downlink control channel is stopped based on the operation of the first and second timers, however, monitoring continues (does not stop) in case the information intended for the UE is actually received. .

In general, improved monitoring of the downlink control channel, as explained above and below, provides additional termination of PDCCH monitoring, which is based on the use of a second timer, and based on the channel busy state of the corresponding unlicensed frequency grid of the unlicensed radio cell. The advantage to be obtained is to reduce the time required for the UE to perform downlink control channel monitoring, and thereby enable the UE to skip monitoring and thus save power.

On the other hand, by stopping function-specific monitoring of the downlink control channel earlier, the UE may be able to move to the next step of the function earlier and therefore reduce the delay for certain procedures. For example, when using the random access function, early termination of the monitoring of the random access response may result in an earlier retransmission of the RACH preamble. Another example is the PDCP reordering feature, which can also benefit from early termination of monitoring since a PDU status report can be sent early to the transmitting side to request retransmission of missing non-sequential PDUs.

The above-described improved downlink control channel monitoring includes determining the busy state of the unlicensed frequency grid channel of the unlicensed radio cell. The UE may determine the busy state of this channel in various ways. According to one exemplary embodiment, the base station periodically transmits a channel busy signal when it has received/occupied an unlicensed frequency grid, while not transmitting a channel busy signal when the base station has not occupied an unlicensed frequency grid. Thus, the UE may at any time infer the channel busy state based on the reception or non-reception of the channel busy signal. Optionally, the channel busy signal may contain information about the expected duration of the gNB channel to be busy. According to another implementation, the channel busy signal is not transmitted periodically, but only at the beginning when an unlicensed frequency grid is received, but the channel busy signal further includes channel busy duration information to enable the UE to determine how long the channel occupation will continue. According to yet another alternative, to indicate the start of channel busy, the gNB transmits a busy channel at the start of channel busy, and sends an additional busy signal at the end of channel busy to indicate the end of channel busy.

In accordance with this 3GPP under discussion, a channel busy signal (also referred to as a COT indication) may be periodically transmitted by a gNB. The content and how it is communicated is yet to be agreed upon. However, the layer 1 (L1) UE can notify the second and third layers of the UE (L2 and L3) about the state of the COT, for example, when the gNB occupies an unlicensed frequency grid and, in some cases (see the options above), when the gNB finishes occupying an unlicensed frequency grid .

As an example, one additional assumption is that the timer value for the first timer is longer when operating to monitor the downlink control channel in an unlicensed radio cell scenario than when operating in a licensed radio cell scenario. As explained earlier, one possible solution for compensating for LBT failures is to increase the duration of the timers controlling the monitoring of the downlink control channel (eg, PDCCH) when operating in an unlicensed radio cell. Accordingly, the gNB configures the UE with a longer timer value when communicating with the UE via an unlicensed radio cell. Then, in order to be able to reduce the additional energy cost for extended monitoring in unlicensed radio cells, where possible, a second timer is implemented, as explained earlier and below. When operating in a licensed radio cell, there is no need to use a second timer.

The first and second timers may be configured in various ways. For example, the first and second timers may be configured separately, for example with gNB. In this regard, the gNB sends configuration information to the UE, including separate instructions for configuring the first and second timers (eg, two different timer values, with the value for the second timer being less than the value for the first timer). This configuration information may be provided separately for each of the controlled functions, resulting in the first and second timers being separately configured for each function.

On the other hand, the first and second timers may be configured together, with one timer configured depending on the other timer, with, for example, the second timer being determined based on the first timer. For example, configuration information may be passed to the gNB to configure the first timer (eg, in the usual way, as already done in prior art solutions, see 3GPP functions described above). The second timer is then determined by the UE as a fraction of the first timer. For example, the value of the first timer relating to the unlicensed frequency grid is multiplied by a scaling factor (eg, 0 to 1) to determine the value of the second timer.

In turn, the scaling factor (or factor) can be, for example, configured by the gNB using a configuration message, for example, in conjunction with configuring a first timer related to the unlicensed frequency grid. Alternatively, the scaling factor may be defined by the 3GPP specification and thus hardcoded into the UE or the UE's SIM card.

In accordance with additional exemplary embodiments, the same or different scaling factors may be used to determine the second timer based on the first timer for different functions performed in the UE. The same scaling factor may be used for all or a subset of the managed functions.

According to further exemplary embodiments, when the gNB decides to change the scale factor value and sends a configuration message to the UE to change the scale factor value, the UE may apply the change gradually over a period of time instead of changing the scale factor value immediately after receiving the configuration message.

According to a further exemplary implementation, the second unlicensed grid timer (used by the UE to monitor the downlink control channel for a function in the unlicensed radio cell) can be configured to be the same or similar to the first licensed grid timer. used by the UE (to monitor the downlink control channel for the function in the licensed radio cell). In particular, the timer value for the second timer associated with the unlicensed frequency grid may be the same or similar to the timer value for the first timer associated with the licensed frequency grid. Reusing the configuration for the first timer associated with the licensed frequency grid to configure the second timer associated with the unlicensed frequency grid facilitates implementation and reduces the impact on 3GPP specifications.

On the other hand, the first timer when operating in an unlicensed radio cell (example referred to as the first timer related to the unlicensed frequency grid) may in turn be configured depending on the first timer when operating in a licensed radio cell (example referred to as the first timer related to the licensed frequency grid). For example, the first timer associated with the unlicensed frequency grid may simply be a multiple of the first timer associated with the licensed frequency grid. Alternatively, the unlicensed frequency grid related first timer may be specified by the 3GPP specification and thus, for example, hardcoded into the UE or the UE's SIM card.

In the 3GPP exemplary implementation, configuration information may be sent to the gNB in the UE using RRC messages.

Two different exemplary implementations of the improved downlink control channel monitoring described above will be described below. The first embodiment will be described with reference to FIG. 12 and 13. The second embodiment will be described with reference to FIG. 14, 15, and 16. The first and second embodiments mainly differ in how the second timer is controlled depending on the busy state of the channel, and the resulting stop of the monitoring procedure of the downlink control channel.

According to the first alternative implementation, the second timer operates to accumulate downlink control channel monitoring execution time while the gNB has occupied an unlicensed frequency grid. In other words, while the first timer runs regardless of channel occupancy to count downlink control channel monitoring time, the second timer runs if the gNB has occupied an unlicensed frequency grid, but does not operate if the gNB has not occupied an unlicensed frequency grid. Thus, the second timer only accumulates time when the gNB is actually able to reach the UE via the unlicensed radio cell (while ignoring other times when the gNB is unable to reach the UE, e.g. due to LBT failures when the unlicensed frequency grid is already occupied and being used by other systems). or other gNBs). Accordingly, the second timer is similar in this regard to the first timer that operates in the licensed radio cell.

FIG. 12 shows that downlink control channel monitoring is started as part of a function. Then, the start of function-specific monitoring initiates the start of the first timer and, as well as the operation of the second timer. However, whether the second timer starts (for the first time), resumes or stops depends on the busy state of the channel. Thus, the UE determines the busy state of the channel of the unlicensed frequency band. By way of illustration, it is assumed that the gNB eventually receives an unlicensed frequency grid (for the first time after monitoring is started), in which case a second timer is started. The second timer continues to run while the channel is busy, and then stops when the unlicensed channel is no longer occupied by the gNB. The second timer may be restarted when the gNB re-occupies the unlicensed frequency grid. Thus, the second timer runs until it expires, in which case monitoring of the downlink control channel is stopped. In some cases, the first timer may also be stopped after the second timer has expired, as there is no need for the first timer to continue, given that monitoring of the downlink control channel has already been stopped based on the second timer (not shown in FIG. 12).

FIG. 13 illustrates an improved downlink control channel monitoring procedure in accordance with the embodiment presented above with reference to FIG. 12 in the example scenario. FIG. 13 illustrates at the top when the downlink control channel (in this case PDCCH) is being monitored, as well as the busyness of the gNB channel (referred to as COT gNB). In the middle of FIG. 13 shows the operation of the first timer, and in the lower part the operation of the second timer. The horizontal dotted lines indicate the value of the respective timers, with the value of the second timer significantly lower than the value of the first timer. When the timer reaches the corresponding timer value (horizontal line), it expires.

As can be seen, the first timer starts simultaneously with PDCCH monitoring and runs continuously independently of the gNB COT. On the other hand, the second timer is not started at the start of PDCCH monitoring, but rather when the gNB receives an unlicensed frequency grid. The second timer runs until the end of the first gNB COT and then resumes on the second gNB COT. In the exemplary scenario, it is assumed that the second timer expires before the end of the second gNB COT and PDCCH monitoring is stopped (as shown at the top of FIG. 13).

FIG. 13 is only an example, hypothetically assuming specific gNB COT timer and duration values. In other scenarios, the second timer may expire earlier than in FIG. 13 (for example, during the first COT of the gNB), or even not expire at all, in which case the first timer may expire first (see FIG. 13 "stopping PDCCH monitoring if the first timer expires" at the top of the right side) .

FIG. 14 shows a flow diagram for a second alternative implementation of an enhanced downlink control channel monitoring procedure. The second alternative implementation differs from the first mainly in how the second timer is controlled. In particular, the second timer starts substantially at the same time as the first timer, such as when PDCCH monitoring starts. Also, the second timer, like the first timer, runs continuously independently of the gNB COT until it expires (or stops because another timer expires first). Upon expiration of the second timer, the UE should evaluate the occupancy state of the unlicensed frequency grid channel (eg, by determining the occupancy of the unlicensed gNB channel in response to the expiration of the second timer). If the base station occupies an unlicensed frequency grid, the UE continues to monitor the PDCCH until the end of this current COT as to whether the gNB (having received the unlicensed frequency grid) is transmitting UE information. Monitoring stops when the busy time of the current gNB channel expires. On the other hand, if the UE determines that the base station has not occupied the unlicensed frequency grid, no specific action is required by the UE, but it monitors the operation of the first timer, and monitoring of the downlink control channel continues until the expiration of the first timer (dashed frame and arrow in FIG. . 14).

Accordingly, the second timer is used to enable a single COT check (after the second timer expires) to stop monitoring earlier when it is determined that the gNB is currently occupying an unlicensed channel. In other words, if the UE determines that the gNB has received an unlicensed frequency grid, but does not transmit any information/data for the UE to the UE (the second timer expires during COT, but no data is received during monitoring), the UE assumes that further monitoring PDCCH is useless; monitoring stops when the gNB COT ends.

The second embodiment of FIG. 14 is simpler than the solution of FIG. 12 because the UE does not continuously determine the channel busy state and does not need to accumulate COT durations. Instead, the UE checks the COT state only once at the moment the second timer expires. However, in cases where the second timer expires during gNB COT, the monitoring time is shortened and thus energy can be saved.

FIG. 15 and 16 illustrate an improved downlink control channel monitoring procedure in accordance with the second alternative presented above with reference to FIG. 14 in two exemplary scenarios. FIG. 15 and 16 are similar to FIG. 13 in that at the top they show when the downlink control channel (in this case PDCCH) is being monitored, as well as the busyness of the gNB (referred to as COT gNB). In the middle of the figures, the operation of the first timer is shown, and in the lower part, the operation of the second timer. The horizontal dotted lines indicate the value of the respective timers, with the value of the second timer significantly lower than the value of the first timer. When the timer reaches the corresponding timer value (horizontal line), it expires.

FIG. 15 assumes, by way of example, that the second timer expires during gNB COT, while in FIG. 16 assumes, by way of example, that the second timer expires outside the COT of the gNB. As seen from FIG. 15, the expiration of the second timer causes the UE to check the state of the COT and thus determine that the gNB has currently occupied an unlicensed frequency grid. The UE continues to monitor the downlink control channel until the end of the current (first in the exemplary scenario) COT, and then stops monitoring, thereby allowing the UE to save power.

On the other hand, as shown in FIG. 16, the expiration of the second timer causes the UE to check the state of the COT and thus determine that the gNB has not currently occupied the unlicensed frequency grid. Thus, the UE continues monitoring the downlink control channel until the expiration of the first timer.

In specific embodiments of the improved monitoring procedure described above shown in FIG. 11-16, it can be implemented in LTE and 5G NR environments as standardized now and in the future. In the above description, specific functions of LTE and 5G NR have been introduced that include monitoring of the downlink control channel (in particular, PDCCH) and thus benefit from an improved monitoring procedure. Some of the various functions and how to implement an improved monitoring procedure in them will be described in detail below.

PDCCH monitoring will be performed as part of the paging function to be able to receive the paging message sent by the base station UE. When implementing the enhanced PDCCH monitoring procedure in the paging function, the first timer may be a timer that counts the duration of the paging event (see TS 38.304 V15.3.0 sections 6.1 and 7.1; TS 38.300 V15.5.0 section 9.2.5). In one exemplary implementation, the value of the first timer can be increased to cover an extended paging event (with a longer duration) or to cover more than one paging event (e.g., sum the duration of multiple paging events) by operating on the unlicensed frequency grid of the unlicensed radio cell. The second timer is then a new timer for the paging function to be used when operating in an unlicensed radio cell. The timer value for the second timer may, for example, be a timer value corresponding to a paging event to be monitored by the UE in the licensed scenario.

The thus configured paging function is then controlled by the UE. The PDCCH monitoring is started at the beginning of the paging event, at which point (at least) the first PO timer is started by the UE. The second SR timer operates in accordance with one of the various implementations described with reference to FIG. 11-16. Accordingly, the second timer starts after the start of PDCCH PO monitoring, specifically with the start of gNB COT, then accumulates PDCCH monitoring time for the remaining gNB COT (and possibly additional gNB COT), and upon expiration, wakes up the UE to stop PDCCH monitoring ( see FIGS 12 and 13). Alternatively, the second timer is started at the same time as the first timer with the start of PDCCH monitoring (see FIGS. 14-16), and upon expiration, the UE wakes up to check the COT status to decide whether to continue monitoring until the COT is completed (when it is determined that the gNB currently received an unlicensed frequency grid) or continue monitoring the PDCCH until the first timer expires (eg, until the end of the paging event). If necessary, in accordance with the current definition of the paging function, after the first and/or second timer expires, the UE may enter the DRX idle state (IDLE-DRX off state).

When a page message is received during PDCCH monitoring (eg, a PDCCH with a P-RNTI and a corresponding PDSCH is received), the UE also no longer needs to continue monitoring the PDCCH for the paging function, and the UE may stop monitoring the PDCCH until the next paging interval (if not required, for example, as part of another function). In addition, two timers can be stopped.

The second PO timer allows the UE to stop PDCCH monitoring earlier (especially when the unlicensed channel is free and the gNB can receive the unlicensed channel). Thus, the UE can save significant power.

In addition, PDCCH monitoring must be performed as part of a system information acquisition function in order to be able to acquire system information. When implementing the enhanced PDCCH monitoring procedure in the system information acquisition function, the first timer may be a timer that counts the duration of the system information window (see TS 38.331 V15.5.1 section 5.2; TS 38.300 v 15.5.0 section 7.3, TS 38.213 section 13). In one exemplary implementation, the value of the first timer can be increased to cover an extended system information window (with a longer duration) or to cover more than one SI window (e.g., summing the durations of multiple SI windows) by operating in the unlicensed frequency grid of an unlicensed radio cell. . The second timer is then a new timer for the SI data collection function to be used when operating in an unlicensed radio cell. The timer value for the second timer may, for example, be a timer value corresponding to the SI window that the UE is to monitor in the licensed scenario.

Then, the thus configured system information acquisition function is controlled by the UE. PDCCH monitoring starts at the start of the SI window, at which point (at least) the first SI window timer is started by the UE. The second window timer SI operates in accordance with one of the various implementations described with reference to FIG. 11-16. Accordingly, a second SI window timer starts after the start of SI window PDCCH monitoring, specifically with the start of the gNB COT, then accumulates the PDCCH monitoring time for the remaining gNB COT (and possibly additional gNB COT), and upon expiration, wakes up the UE to stop PDCCH monitoring (see FIGS. 12 and 13). Alternatively, the second timer is started at the same time as the first timer with the start of PDCCH monitoring (see FIGS. 14-16), and upon expiration, the UE wakes up to check the COT status to decide whether to continue monitoring until the COT is completed (when it is determined that the gNB currently received an unlicensed frequency grid) or continue monitoring the PDCCH until the expiration of the first timer (eg until the end of the SI window). In addition, when the SI message is not received successfully and PDCCH monitoring is stopped, the UE may restart receiving system information in the next SI period.

If a system information message is received during PDCCH monitoring (eg, PDCCH with SI-RNTI and corresponding PDSCH), the UE no longer needs to continue monitoring the PDCCH for the SI receive function, and the UE may stop monitoring the PDCCH until the next reception of new system information (if it is not required, for example, as part of another function). In addition, two timers can be stopped.

Thus, the second SI window timer allows the UE to stop PDCCH monitoring earlier (especially when the unlicensed channel is free and the gNB can receive the unlicensed channel). Thus, the UE can save significant power.

In addition, monitoring of the PDCCH should be performed within the DRX function on duration period to check whether any information destined for the UE has been received and whether to determine whether to enter the DRX off state or not. When implementing the enhanced PDCCH monitoring procedure in the DRX function, the first timer may be a timer that counts the length of the on duration period (on duration timer; see TS 38.321 V15.5.0 section 5.7). In one exemplary implementation, the value of the first timer may be increased to cover the increased on duration (with longer length) due to operating on an unlicensed frequency grid of an unlicensed radio cell. Then the second timer is a new timer to control the duration of the on, which will be used when operating in an unlicensed radio cell. The timer value for the second timer may be, for example, a timer value corresponding to an on-duration period that the UE is to monitor in the licensed scenario.

The thus configured DRX duration control is then performed by the UE. The PDCCH monitoring starts at the start of the DRX On Duration period, at which point (at least) the first On Duration timer is started by the UE. The second on duration timer is controlled in accordance with the various embodiments explained with reference to FIG. 11-16. Accordingly, the second on-duration timer starts after the start of PDCCH on-duration monitoring, specifically with the start of gNB COT, then accumulates PDCCH monitoring during the remaining gNB COT (and possibly additional gNB COTs), and upon expiration wakes up the UE to stop monitoring. PDCCH (see FIGS. 12 and 13). Alternatively, the second on-duration timer starts at the same time as the first on-duration timer at the start of PDCCH monitoring (see FIGS. 14-16), and upon expiration, the UE wakes up to check the COT status to decide whether to continue monitoring until the COT is completed (when determined that the gNB has currently received an unlicensed frequency grid) or continue monitoring the PDCCH until the expiration of the first timer (eg, until the end of the on-duration period). In addition, when no PDCCH is received for the UE and PDCCH monitoring is stopped based on the first or second on-duration timers, the UE may transition to a DRX-off state.

On the other hand, when a PDCCH for a UE is received during PDCCH monitoring (eg, downlink enabled or uplink enabled), the UE no longer needs to continue monitoring the PDCCH based on the on-duration configuration (eg, the UE continues downlink grant processing or uplink permission, and then proceeds to the next PDCCH monitoring step). In addition, at the same time as determining the current DRX, the UE may perform PDCCH monitoring as part of DRX sleep timer control, as will be explained in connection with the next function.

Thus, the second on-duration timer allows the UE to stop PDCCH on-duration monitoring earlier (especially when the unlicensed channel is idle and the gNB can receive the unlicensed channel). Thus, the UE can save significant power.

In addition, PDCCH monitoring should be performed as part of the DRX function sleep timer to check if any information destined for the UE has been received and if the UE should enter a DRX cycle (due to extended sleep; see TS 38.321 V15. 5.0, section 5.7). When implementing the enhanced PDCCH monitoring procedure in the DRX function, the first timer may be a DRX sleep timer that counts the sleep duration. In one exemplary implementation, the value of the first timer may be increased to cover an extended period of inactivity (with a longer duration) due to operating on an unlicensed frequency grid of an unlicensed radio cell. The second timer is then a new idle monitoring timer to be used when operating in an unlicensed radio cell. The timer value for the second timer may be, for example, a timer value corresponding to the idle timer configured for the UE in the licensed scenario.

Then, the thus configured DRX sleep function control is performed by the UE. PDCCH monitoring starts at the start of the DRX sleep period, at which point (at least) the first sleep timer. The second sleep timer operates in accordance with the various embodiments described with reference to FIG. 11-16. Accordingly, a second sleep timer starts after the start of PDCCH idle monitoring, specifically with the start of gNB COT, then accumulates PDCCH monitoring during the remaining gNB COT (and possibly additional gNB COT), and upon expiration, wakes up the UE to stop PDCCH monitoring ( see FIGS 12 and 13). Alternatively, the second sleep timer is started at the same time as the first sleep timer with the start of PDCCH monitoring (see FIGS. 14-16), and after its expiration, the UE wakes up to check the status of the COT to decide whether to continue monitoring until the end of the COT (when determined, that the gNB has currently received an unlicensed frequency grid) or continue to monitor the PDCCH until the first timer expires (eg, until the end of the idle period). In addition, when no PDCCHs are received for the UE and PDCCH monitoring is stopped based on the first or second idle timers, the UE may then enter a short DRX cycle if configured.

On the other hand, when a PDCCH for the UE is received during PDCCH monitoring (eg, downlink enabled or uplink enabled), the UE restarts the first and second idle timers, respectively, and continues monitoring the PDCCH.

Thus, the second idle timer allows the UE to stop PDCCH idle monitoring earlier (especially when the unlicensed channel is free and the gNB can receive the unlicensed channel). Thus, the UE can save significant power.

In addition, monitoring of the PDCCH should be performed as part of the random access function to check if a random access response message has been received from the gNB in response to the RACH preamble sent by the gNB UE previously. When implementing the improved PDCCH monitoring procedure in the random access function, the first timer may be a timer for counting the duration of the Random Access Response (RAR) window (for example, ra-ResponseWindow; see TS 38.321 v15.5.0, section 5.1). In one exemplary implementation, the value of the first timer may be increased to cover an extended RAR window (with longer duration) due to operating on an unlicensed frequency grid of an unlicensed radio cell. Then the second timer is a new RAR monitoring timer to be used when operating in an unlicensed radio cell. The value for the second timer may be, for example, a timer value corresponding to the RAR window size configured for the UE in the licensed scenario.

Then, the thus configured random access function control is performed by the UE. PDCCH monitoring starts at the start of the RAR window, at which point (at least) the first sleep timer is started by the UE. The second RAR window timer operates in accordance with the various implementations described with reference to FIG. 11-16. Accordingly, the second RAR window timer starts after the start of RAR window monitoring, specifically with the start of gNB COT, then accumulates PDCCH monitoring during the remaining gNB COT (and possibly additional gNB COT), and upon expiration, wakes up the UE to stop PDCCH monitoring. (see FIGS. 12 and 13). Alternatively, the second RAR window timer is started at the same time as the first RAR window timer with the start of PDCCH monitoring (see FIGS. 14-16), and after its expiration, the UE wakes up to check the status of the COT to decide whether to continue monitoring until the end of the COT (when determined that the gNB has currently received an unlicensed frequency grid) or continue monitoring the PDCCH until the expiration of the first timer (eg, until the end of the RAR window). In addition, when no random access response is received for the UE and PDCCH monitoring is stopped based on the first or second RAR window timers, the UE may then proceed to the next step of the RACH procedure (eg, RACH preamble retransmission).

On the other hand, when a RAR is received during PDCCH monitoring, the UE continues with random access (eg, with message 3).

Thus, the second RAR window timer allows the UE to stop RAR monitoring earlier (especially when the unlicensed channel is free and the gNB can receive the unlicensed channel). Thus, the UE can save significant power. In addition, since the next random access stage can be started earlier, improved PDCCH monitoring can reduce the random access delay.

In addition, monitoring of the PDCCH should be performed as part of the PDCP reordering function to check if missing PDUs are being received in order to be able to ensure that data packets are forwarded sequentially to higher layers. When implementing the enhanced PDCCH monitoring procedure in the PDCP reordering function, the first timer may be a reordering timer counting the duration of the PDCP reordering window (e.g., t-reordering timer; see TS 38.323 v15.5.0, sections 5.1.2, 5.2.1, 5.2.2 ). In one exemplary implementation, the value of the first timer may be increased to cover an extended PDCP reordering window (longer) due to operating on an unlicensed frequency grid of an unlicensed radio cell. The second timer is then a new timer for the PDCP reordering window to be used when operating in an unlicensed radio cell. The timer value for the second timer may be, for example, a timer value corresponding to the PDCP reorder window configured for the UE in the licensed scenario.

Then, the thus configured control of the PDCP reordering function is performed by the UE. PDCCH monitoring is started at the beginning of the PDCP reordering window, at which point (at least) the first reordering timer is started by the UE. The second reorder timer operates in accordance with the various embodiments described with reference to FIG. 11-16. Accordingly, the second reordering timer starts after the start of monitoring the reordering window, specifically with the start of gNB COT, then accumulates PDCCH monitoring during the remaining gNB COT (and possibly additional gNB COTs), and upon expiration wakes up the UE to stop PDCCH monitoring ( see FIGS 12 and 13). Alternatively, the second reordering window timer is started at the same time as the first reordering window timer with PDCCH monitoring started (see FIGS. 14-16), and upon expiration, the UE wakes up to check the COT state to decide whether to continue monitoring until the COT is completed (when determined that the gNB has currently received an unlicensed frequency grid) or continue monitoring the PDCCH until the expiration of the first timer (eg, until the end of the reordering window). In addition, when missing data packets (those packets that enable sequential transmission to upper layers) are not received and PDCCH monitoring is stopped based on the first or second reorder window timers, then the UE may proceed to the next step of the PDCP data exchange (e.g., gNB transmission PDCP status report to request retransmission of missing PDUs).

On the other hand, when missing data packets are received during PDCCH monitoring, then the UE stops PDCCH monitoring for the reordering function (eg, all packets are in sequence and no reordering is currently required) until the next time reordering is required. In addition, the UE may proceed to serial transmission of data packets to higher layers. Thus, the second reordering window timer allows the UE to stop monitoring the reordering earlier (especially when the unlicensed channel is free and the gNB is able to receive the unlicensed channel). Thus, the UE can save significant power. In addition, since the next step of the reordering function can be performed earlier (eg, PDCP status reporting), improved PDCCH monitoring can reduce PDCP latency (lower data receive latency due to earlier retransmission).

The above description of enhanced downlink control channel monitoring has been focused on the UE side. However, improved downlink control channel monitoring is also applicable to the gNB side. The various functions described above involve monitoring the PDCCH, while from the point of view of the gNB, the various functions involve the transmission of PDCCH information. In particular, while the UE must perform PDCCH monitoring as part of a particular function, the inverse operation of the gNB is to send the corresponding PDCCH information to the UE. Therefore, the gNB may perform the same or similar parallel operation of the two timers to determine when the UE is monitoring the downlink control channel, to determine when to transmit information to the UE via the downlink control channel. For example, the gNB may only transmit to the UE on the PDCCH when it has determined that the UE is actually monitoring the PDCCH at that point in time; otherwise, the PDCCH transmission is not required because the UE does not monitor the PDCCH and will not receive the PDCCH transmission anyway. Accordingly, the various embodiments and embodiments disclosed above with reference to FIG. 11-16 can be applied appropriately to the operation of gNB.

For example, according to one exemplary implementation, the base station determines when the UE performs PDCCH monitoring based on the operation of the first and second timers, as shown in FIG. 11 or based on the first embodiment explained with reference to FIG. 12 and 13, or based on the second embodiment explained with reference to FIG. 14, 15 and 16.

In addition, the base station is also responsible for configuring various functions in the UE, including the first and second timers and their values. For the specified gNB, MAY send the appropriate configuration using RRC protocol messages.

Additional aspects

According to a first aspect, a UE is provided that comprises a processing circuit that performs a function that includes monitoring a downlink control channel of an unlicensed radio cell for information intended for the UE, wherein the unlicensed radio cell operates on an unlicensed frequency grid and is controlled by a base station that communicates with user equipment. The processing circuit and the UE receiver monitor the downlink control channel based on the first timer and the second timer operating in parallel. The first timer is used to limit the maximum time that monitoring of the downlink control channel must be performed by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring of the downlink control channel after the first timer expires. The second timer is used to stop the monitoring of the downlink control channel before the first timer depending on the busy state of the unlicensed grid channel of the radio cell by the base station.

According to a second aspect provided in addition to the first aspect, the second timer is activated to accumulate the time that the downlink control channel is monitored during the time that the unlicensed spectrum is occupied by the base station. In one optional implementation, the second timer runs during the time that the unlicensed frequency grid is occupied by the base station. In yet another optional implementation, monitoring of the downlink control channel is performed when either of the two timers are running, and upon expiration of either of the first and second timers, monitoring of the downlink control channel is stopped. In yet another optional implementation, a second timer is started when the base station occupies an unlicensed frequency grid for the first time after the start of the first timer, a second timer is suspended when the base station does not occupy an unlicensed frequency grid, and a second timer is started when the base station occupies an unlicensed frequency grid again. frequencies.

According to a third aspect provided in addition to the second aspect, the function is a paging message monitoring function, wherein monitoring of the downlink control channel is performed to receive the paging message. After receiving the page message, the first timer, the second timer, and downlink control channel monitoring for the page message monitoring function are stopped until the next paging interval. In one optional implementation, the first timer counts the duration of one or more paging events and the second timer counts the duration of one or more paging events during the time that the unlicensed frequency grid is occupied by the base station.

Additionally or alternatively, the function is a system information acquisition function, wherein monitoring of the downlink control channel is performed to receive the system information message. After receiving the system information message, the first timer, the second timer, and monitoring of the downlink control channel for the system information acquisition function are stopped until the next time the UE needs to obtain system information. In one optional implementation, the first timer counts the duration of one or more system information acquisition windows, and the second timer counts the duration of one or more system information acquisition windows during the time that the unlicensed frequency grid is occupied by the base station.

Additionally or alternatively, the function is a signaling monitoring operation for the discontinuous DRX reception function, wherein monitoring of the downlink control channel is performed to detect any downlink control information about the downlink control channel directed to the user equipment. Upon receipt of said downlink control information, the first timer and the second timer are stopped, and monitoring of the downlink control channel continues. In one optional implementation, the first timer counts the DRX on duration and the second timer counts the DRX on duration during the time that the unlicensed frequency grid is occupied by the base station.

Additionally or alternatively, the function is an idle monitoring operation for the discontinuous DRX reception function, wherein monitoring of the downlink control channel is performed to detect any downlink control information on the downlink control channel directed to the user equipment. Upon receipt of said downlink control information, the first timer and the second timer are restarted, and monitoring of the downlink control channel continues. In one optional implementation, the first timer counts the duration of the DRX idle time and the second timer counts the duration of the DRX idle during the time that the unlicensed frequency grid is occupied by the base station.

Additionally or alternatively, the function is to receive a random access response for the random access function, wherein monitoring of the downlink control channel is performed to detect a random access response message transmitted by the base station in response to a random access preamble previously transmitted by the base station user equipment. After receiving said random access response, the first timer and the second timer are stopped and the next step of the random access function is executed. In one optional implementation, the first timer counts the duration of the random access response window and the second timer counts the duration of the random access response window during the time that the unlicensed frequency grid is occupied by the base station.

Additionally or alternatively, the function is a Packet Data Convergence Protocol (PDPC) layer reordering function that monitors the downlink control channel to detect missing non-sequential data sent to the user equipment. Upon receipt of said missing non-sequential data, the first timer and the second timer are stopped until the next point in time when non-sequential data transmission is detected and monitoring of the downlink control channel continues. In one optional implementation, the first timer counts the duration of the reordering time window and the second timer counts the duration of the reordering time window during the time that the unlicensed frequency grid is occupied by the base station.

According to a fourth aspect provided in addition to the first aspect, after the expiration of the second timer, the processing circuit determines whether the base station has currently occupied an unlicensed frequency band. When the base station has currently occupied an unlicensed frequency grid, monitoring is stopped at the end of the current occupation of the channel of the unlicensed frequency grid and, if necessary, the first timer is stopped. When the base station has not currently occupied an unlicensed frequency grid, monitoring is performed until the expiration of the first timer. In one optional implementation, the second timer starts at the same time as the first timer.

According to a fifth aspect provided in addition to the fourth aspect, the function is a paging monitoring function in which a downlink control channel is monitored to receive a paging message. After receiving the page message, the first timer, the second timer, and downlink control channel monitoring for the page message monitoring function are stopped until the next paging interval. In one optional implementation, the first and second timers count the duration of one or more paging events.

Additionally or alternatively, the function is a system information acquisition function in which a downlink control channel is monitored to receive a system information message. After receiving the system information message, the first timer, the second timer, and monitoring of the downlink control channel for the system information acquisition function are stopped until the next time the UE needs to obtain system information. In one optional implementation, the first and second timers count the duration of one or more system information acquisition windows.

Additionally or alternatively, the function is a signaling monitoring operation for the DRX discontinuous reception function, wherein monitoring of the downlink control channel is performed to detect any downlink control information on the downlink control channel directed to the user equipment. Upon receipt of said downlink control information, the first timer and the second timer are stopped, monitoring of the downlink control channel continues, and a timer for the duration of the DRX inactivity is started, if necessary. In one optional implementation, the first and second timers count the DRX on duration.

Additionally or alternatively, the function is an idle monitoring operation for the discontinuous DRX reception function, wherein monitoring of the downlink control channel is performed to detect any downlink control information on the downlink control channel directed to the user equipment. Upon receipt of said downlink control information, the first timer and the second timer are restarted, and monitoring of the downlink control channel continues. In one optional implementation, the first and second timers count the duration of the DRX inactivity.

Additionally or alternatively, the function is to receive a random access response for a random access function in which a downlink control channel is monitored to detect a random access response message transmitted by the base station in response to a random access preamble transmitted earlier by the base station user equipment. . After receiving said random access response, the first timer and the second timer are stopped and the next step of the random access function is executed. In one optional implementation, the first and second timers count the length of the random access response window.

Additionally or alternatively, the function is a Packet Data Convergence Protocol (PDPC) layer reordering function that monitors the downlink control channel to detect missing data from the sequence sent to the user equipment. Upon receipt of said missing non-sequential data, the first timer and the second timer are stopped until the next point in time when non-sequential data transmission is detected, and monitoring of the downlink control channel continues. In one optional implementation, the first and second timers count the length of the reorder time window.

According to a sixth aspect provided in addition to one of the first to fifth aspects, the processing circuit determines the channel occupancy by the base station based on the channel busy signal received by the receiver from the base station. In one optional implementation, the channel busy signal is transmitted by the base station when the base station occupies an unlicensed frequency grid and is not transmitted by the base station when the base station does not occupy an unlicensed frequency grid. In one optional implementation, the channel busy signal indicates the length of time that the unlicensed frequency band has been occupied by the base station.

According to a seventh aspect provided in addition to one of the first to sixth aspects, the receiver receives configuration information from the base station configuring a first timer value for the first timer. The processing circuit determines the second timer value for the second timer based on the proportion of the timer value for the first timer. In one optional implementation, this proportion is determined based on the received configuration information. In yet another optional implementation, this same fraction is used to determine the second timer value for one or more of the running functions mentioned below (e.g., paging monitoring functions, system information retrieval functions, signaling monitoring operations for the DRX intermittent reception function, idle monitoring operations for DRX discontinuous reception function, random access response reception for random access function, and packet data convergence protocol layer reordering function.Alternatively, the receiver receives configuration information from the base station configuring a first timer value for the first timer and a second timer value for the second timer.

In one optional implementation of the two alternatives, the second timer value for the second timer is less than the first timer value for the first timer. In yet another optional implementation of the two alternatives, the configuration information is received using a Radio Resource Control (RRC) protocol message.

According to an eighth aspect provided in addition to one of the first to seventh aspects, the controlled function is one of the following functions controlled by the user equipment:

• function of monitoring of paging messages,

• the function of collecting system information,

• signaling monitoring operation for the DRX intermittent reception function,

• an idle monitoring operation for the DRX intermittent reception function,

• receiving a random access response for the random access function, and

• PDCP packet data convergence protocol layer reordering function.

In one optional implementation of the above, the UE performs one or more of the above functions, and each of the functions performed separately includes monitoring a downlink control channel and operating a first timer and a second timer in accordance with one of the first to seventh aspects above.

According to a ninth aspect provided in addition to one of the first to eighth aspects, the first timer value for the first timer and the second timer value for the second timer are configured to operate the function in an unlicensed radio cell. In order for the feature to work, a different first timer value for the first timer is configured in the licensed radio cell. Said different value of the first timer in the licensed radio cell is less than the value of the first timer in the unlicensed radio cell. In one optional implementation, the second timer value for the second timer is the same as the first timer value for the first timer configured to operate in the licensed radio cell.

According to a tenth aspect, a base station is provided, comprising a processing circuit that performs a function including transmitting information to a UE on a downlink control channel of an unlicensed radio cell monitored by the UE to detect information intended for the UE. An unlicensed radio cell operates on an unlicensed frequency grid and is controlled by a base station that communicates with the user equipment. The processing scheme determines when the UE monitors the downlink control channel based on the first timer and the second timer operating in parallel to determine when to transmit UE information via the downlink control channel. The first timer is used to limit the maximum time that the UE should monitor the downlink control channel by starting the first timer at the start of monitoring the downlink control channel and stopping the monitoring of the downlink control channel after the first timer expires. The second timer is used to stop the monitoring of the downlink control channel before the first timer depending on the busy state of the unlicensed grid channel of the radio cell by the base station. The base station transmitter transmits UE information on the downlink control channel based on the previous determination based on the first and second timers.

According to an eleventh aspect provided in addition to the tenth aspect, the transmitter transmits configuration information to the UE for configuring a first timer value for the first timer. The processing circuit determines the second timer value for the second timer based on the proportion of the timer value for the first timer. In one optional embodiment of the invention, the transmitter transmits share configuration information to the UE during operation. Alternatively, the transmitter sends configuration information to the UE for configuring a first timer value for the first timer and a second timer value for the second timer.

In one optional implementation of the above two options, the value of the second timer for the second timer is less than the value of the first timer for the first timer. In yet another optional implementation for the above two alternatives, the configuration information is transmitted using a Radio Resource Control (RRC) protocol message.

According to a twelfth aspect, a method is provided, including the following steps performed by a UE:

performing a function that includes monitoring the downlink control channel of the unlicensed radio cell for information intended for the UE, wherein the unlicensed radio cell operates in an unlicensed frequency grid and is controlled by a base station that communicates with the user equipment,

performing monitoring of the downlink control channel based on the first timer and the second timer operating in parallel. The first timer is used to limit the maximum time that monitoring of the downlink control channel must be performed by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring of the downlink control channel after the first timer expires. The second timer is used to stop the monitoring of the downlink control channel before the first timer depending on the busy state of the unlicensed grid channel of the radio cell by the base station.

Implementation of Hardware and Software According to the Present Disclosure

The present invention may be implemented in software, hardware, or software in conjunction with hardware. Each of the functional blocks used in describing each of the above embodiments may be partially or wholly implemented by a large integrated circuit (LSI), such as an integrated circuit, and each of the processes described in each of the embodiments may be partially or wholly controlled. one LSI or a combination of LSI.LSI can be made separately in the form of chips, or one chip can be made in such a way that it contains part of the functional blocks or all of the functional blocks. An LSI may contain inputs and outputs associated with it. LSI in this document may be referred to as 1C (integrated circuit), system LSI, super LSI or ultra LSI, depending on the difference in the degree of integration. However, the implementation method of the integrated circuit is not limited to LSI, and may be implemented using a dedicated circuit, a general purpose processor, or a special purpose processor. In addition, a field programmable gate array (FPGA) may be used, which may be programmed after the manufacture of the LSI or a reconfigurable processor in which the connections and settings of the circuit elements located in the LSI can be reconfigured. The present invention may be implemented in the form of digital processing or analog processing. If the latest integrated circuit technology replaces current LSIs as a result of advances in semiconductor technology or other technology derived therefrom, functional blocks can be built using said latest integrated circuit technology. Biotechnology may also be applied.

The present disclosure may be implemented by any type of equipment, device or system having a communication function, referred to as a communication device.

Some non-limiting examples of such a communication device include a telephone (e.g., cell phone, smartphone), tablet, personal computer (PC) (e.g., laptop, desktop, netbook), camera (e.g., digital photo/video camera), digital player (digital audio/video player), wearable device (e.g., wearable camera, smart watch, tracking device), game console, digital book reader, telemedicine/remote medicine device ( remote health and medicine) and a vehicle with communication functions (e.g. car, plane, ship), as well as their various combinations.

The communication device is not limited to portable or mobile, and may also include any kind of installation, device, or system that is not portable or stationary, such as a smart home device (e.g., home appliance, lighting system, smart meter, control panel), vending machine, and any other "things" in the network "Internet of Things" (Internet of Things, IoT).

The communication may include data exchange, for example, via a cellular system, a wireless LAN communication system, a satellite system, etc., as well as various combinations thereof.

The communication device may include a device, such as a controller or sensor, associated with the communication device that performs the communication function disclosed in the present description. For example, the communication device may include a controller or sensor that generates control signals or data signals that are used by the communication device that performs the communication function of the communication device.

The communications device may also include an infrastructure entity such as a base station, access point, and any other equipment, device, or system that communicates with or controls devices, such as in the non-limiting examples above.

In addition, various embodiments may also be implemented by software modules that are executed by a processor or implemented directly in hardware. A combination of software modules and hardware blocks may also be possible. Program modules may be stored in any form of computer-readable storage media, such as random access memory (RAM), erasable programmable read-only memory (EPROM), flash memory, registers, hard drives, CD-ROMs and DVDs, and the like. . It should also be noted that individual features of various embodiments can be selectively or in an arbitrary combination used in another embodiment.

One skilled in the art will appreciate that many changes and/or modifications can be made to the present invention as depicted in particular embodiments. Thus, the present embodiments of the invention are to be considered in all respects as illustrative and non-limiting.

Claims (79)

1. User equipment (UE), containing: a receiver that, in operation, receives a downlink control channel of the unlicensed radio cell for information intended for the UE, the unlicensed radio cell operating in an unlicensed frequency band and controlled by a base station that communicates with the UE; And a processing circuit that, in operation, monitors the downlink control channel using a first timer and a second timer, wherein the first timer limits the maximum time for monitoring the downlink control channel by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring the downlink control channel after the first timer expires, wherein the second timer stops monitoring the downlink control channel after detecting the busy state of the unlicensed grid channel of the radio cell by the base station, and stops monitoring the downlink control channel before the first timer. 2. User equipment according to claim 1, wherein the second timer accumulates downlink control channel monitoring time during the time that the unlicensed frequency grid is occupied by the base station. 3. User equipment according to claim 1, in which, after the second timer expires, the processing circuit in the course of operation determines whether the base station has currently occupied an unlicensed frequency grid, when the base station currently occupies an unlicensed frequency grid, monitoring stops when the current occupation of the channel of the unlicensed frequency grid ends, when the base station has not currently occupied an unlicensed frequency grid, monitoring is performed until the expiration of the first timer. 4. The user equipment according to claim 1, wherein the processing circuit performs monitoring of the downlink control channel for receiving the paging message, and after receiving the paging message, the first timer, the second timer, and monitoring of the downlink control channel for the paging message are stopped until next paging interval. 5. The user equipment of claim. 1, in which the processing circuit determines the occupation of the channel by the base station based on the channel busy signal received by the receiver from the base station, moreover, the channel busy signal is transmitted by the base station when the base station occupies an unlicensed frequency grid, and is not transmitted by the base station when the base station does not occupy an unlicensed frequency grid, wherein the channel busy signal indicates the length of time that the unlicensed frequency grid has been occupied by the base station. 6. User equipment according to claim 1, wherein the receiver, in operation, receives from the base station configuration information configuring a first timer value for the first timer and a second timer value for the second timer, wherein the value of the second timer for the second timer is less than the value of the first timer for the first timer. 7. The user equipment of claim 1, wherein the processing circuit controls one of the following: • monitoring of the paging message, • receiving system information, • signaling monitoring operation for discontinuous reception (Discontinued Reception, DRX), • operation monitoring inactivity for discontinuous reception (Discontinued Reception, DRX), • receiving a random access response for random access, and • reordering of the Packet Data Convergence Protocol (PDCP) layer. 8. The user equipment of claim 1, wherein the first timer value for the first timer and the second timer value for the second timer are configured to operate in an unlicensed radio cell, wherein a different first timer value for the first timer is configured to operate in a licensed radio cell, said different the value of the first timer in the licensed radio cell is less than the value of the first timer in the unlicensed radio cell, wherein the value of the second timer for the second timer is the same as the value of the first timer for the first timer configured to operate in the licensed radio cell. 9. Base station, comprising: a processing circuit that, in operation, controls the transmission of information to a user equipment (UE) on a downlink control channel of an unlicensed radio cell, which is monitored by the UE using a first timer and a second timer, moreover, an unlicensed radio cell operates in an unlicensed frequency grid and is controlled by a base station that communicates with the UE, wherein the first timer limits the maximum time for monitoring the downlink control channel by the UE by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring the downlink control channel after the first timer expires, wherein the second timer stops monitoring the downlink control channel after detecting the busy state of the unlicensed grid channel of the radio cell by the base station and stops monitoring the downlink control channel before the first timer, and a transmitter that transmits UE information on a downlink control channel during operation. 10. The base station of claim 9, wherein the transmitter during operation transmits configuration information to the UE for configuring the first timer value for the first timer, and wherein the during operation processing circuit determines the second timer value for the second timer based on the proportion of the timer value for first timer. 11. A method for communicating with a base station over a wireless channel, including the following steps performed by a user equipment (UE): controlling the monitoring of the downlink control channel of the unlicensed radio cell to detect information intended for the UE, wherein the unlicensed radio cell operates in an unlicensed frequency grid and is controlled by a base station that communicates with the user equipment, performing downlink control channel monitoring using a first timer and a second timer operating in parallel, wherein the first timer limits the maximum time for monitoring the downlink control channel by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring the downlink control channel after the first timer expires, and wherein the second timer stops monitoring the downlink control channel after detecting the busy state of the unlicensed grid channel of the radio cell by the base station, and stops monitoring the downlink control channel before the first timer. 12. The method of claim 11, wherein the second timer accumulates downlink control channel monitoring time during the time that the unlicensed frequency grid is occupied by the base station. 13. The method according to p. 11, in which after the expiration of the second timer determining whether the base station has currently occupied an unlicensed frequency grid, when the base station has currently occupied an unlicensed frequency grid, monitoring is stopped at the end of the current occupation of the channel of the unlicensed frequency grid, when the base station has not currently occupied the unlicensed frequency grid, monitoring is performed until the expiration of the first timer. 14. The method according to p. 11, wherein monitoring of the downlink control channel for receiving the paging message is performed, and after receiving the paging message, the first timer, the second timer, and monitoring of the downlink control channel for the paging message are stopped until the next paging interval. 15. The method of claim 11, wherein the processing circuit determines whether the channel is occupied by the base station based on the channel busy signal received by the receiver from the base station, wherein the channel busy signal is transmitted by the base station when the base station occupies an unlicensed frequency grid, and is not transmitted by the base station when the base station does not occupy an unlicensed frequency grid, wherein the channel busy signal indicates the length of time that the unlicensed frequency grid has been occupied by the base station. 16. The method according to p. 11, wherein the configuration information is received from the base station configuring the first timer value for the first timer and the second timer value for the second timer, wherein the value of the second timer for the second timer is less than the value of the first timer for the first timer. 17. The method according to p. 11, in which one of the following is done: • monitoring of the paging message, • obtaining system information, • signaling monitoring operation for discontinuous reception (DRX), • an idle monitoring operation for discontinuous reception (DRX), • receiving a random access response for random access, and • reordering of the Packet Data Convergence Protocol (PDCP) layer. 18. The method of claim 11, wherein a first timer value for the first timer and a second timer value for the second timer are configured to operate in an unlicensed radio cell, wherein a different first timer value for the first timer is configured to operate in a licensed radio cell, wherein said different first timer value timer in the licensed radio cell is less than the value of the first timer in the unlicensed radio cell, wherein the value of the second timer for the second timer is the same as the value of the first timer for the first timer configured to operate in the licensed radio cell. 19. A method for exchanging data with a user equipment (UE) over a wireless channel, including the following steps performed by the base station: performing a function that includes transmitting information to a user equipment (UE) on a downlink control channel of an unlicensed radio cell, which is monitored by the UE using a first timer and a second timer to detect information intended for the UE, the unlicensed radio cell operating in an unlicensed frequency grid, and controlled by a base station that communicates with the UE, determining when the UE monitors the downlink control channel based on the first timer and the second timer operating in parallel to determine when to transmit UE information via the downlink control channel, wherein the first timer is used to limit the maximum downlink control channel monitoring time to be monitored by the UE by starting the first timer at the start of downlink control channel monitoring and stopping the downlink control channel monitoring after the first timer expires, wherein the second timer is used to stop monitoring the downlink control channel after detecting the busy state of the unlicensed grid channel of the radio cell by the base station and stop monitoring the downlink control channel before the first timer, and transmitting information to the UE on a downlink control channel. 20. An integrated circuit that, during operation, controls a user equipment (UE) process, including: controlling the monitoring of the downlink control channel of the unlicensed radio cell to detect information intended for the UE, wherein the unlicensed radio cell operates in an unlicensed frequency grid and is controlled by a base station that communicates with the user equipment, performing downlink control channel monitoring using a first timer and a second timer operating in parallel, wherein the first timer limits the maximum time for monitoring the downlink control channel by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring the downlink control channel after the first timer expires, wherein the second timer stops monitoring the downlink control channel after detecting the busy state of the unlicensed grid channel of the radio cell by the base station, and stops monitoring the downlink control channel before the first timer. 21. An integrated circuit that, during operation, controls the process of the base station, including: performing a function that includes transmitting information to a user equipment (UE) on a downlink control channel of an unlicensed radio cell, which is monitored by the UE using a first timer and a second timer to detect information intended for the UE, the unlicensed radio cell operating in an unlicensed frequency grid, and controlled by the base station that communicates with the UE, determining when the UE monitors the downlink control channel based on the first timer and the second timer operating in parallel to determine when to transmit UE information through the downlink control channel, wherein the first timer is used to limit the maximum time for monitoring the downlink control channel to be monitored by the UE by starting the first timer at the start of monitoring the downlink control channel and stopping monitoring the downlink control channel after the first timer expires, wherein the second timer is used to stop monitoring the downlink control channel after the base station detects the busy state of the unlicensed grid channel of the radio cell and stop monitoring the downlink control channel before the first timer, and transmitting information to the UE on a downlink control channel.

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