HK40006105A - Paging detection window - Google Patents

Description

Paging detection window

Technical Field

The present invention relates to the field of wireless communications. More particularly, the present invention relates to methods, apparatus, systems and computer programs for detection of paging messages.

Background

A communication system may be seen as a facility that enables communication sessions between two or more entities, such as user terminals, base stations and/or other nodes, by providing carriers between the various entities involved in a communication path. A communication system may be provided, for example, by a communication network and one or more compatible communication devices. A communication session may include, for example, a communication for carrying data such as communications of voice, electronic mail (email), text messages, multimedia, and/or content data. Non-limiting examples of services provided include two-way or multi-way calls, data communication or multimedia services, and access to data network systems such as the internet.

In a wireless communication system, at least a portion of a communication session between at least two stations occurs over a wireless link. Examples of wireless systems include Public Land Mobile Networks (PLMNs), satellite-based communication systems, and different wireless local networks, such as Wireless Local Area Networks (WLANs). Wireless systems can generally be divided into cells and are therefore commonly referred to as cellular systems.

A user may access the communication system through a suitable communication device or terminal. The communication devices of the users are commonly referred to as User Equipment (UE). The communication device is provided with suitable signal receiving and transmitting means for enabling communication, for example enabling access to a communication network or communication directly with other users. A communication device may access a carrier provided by a station, e.g., a base station of a cell, and transmit and/or receive communications on the carrier.

A communication system and related devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters for the connection are also typically defined. An example of an attempt to address the problems associated with increased capacity demand is the architecture of Long Term Evolution (LTE) known as Universal Mobile Telecommunications System (UMTS) radio access technology. LTE is being standardized by the third generation partnership project (3 GPP). Various development stages of the 3GPP LTE specifications are referred to as releases. Certain versions of 3GPP LTE (e.g., LTE Rel-11, LTE Rel-12, LTE Rel-13, LTE Rel-14) are directed to LTE advanced (LTE-A). LTE-a aims to extend and optimize 3gpp LTE radio access technologies.

A communication system may be configured to use mechanisms for aggregating radio carriers to support a wider transmission bandwidth. In LTE, this mechanism is referred to as Carrier Aggregation (CA). A communication device with reception and/or transmission capabilities for CA may simultaneously receive and/or transmit on multiple Component Carriers (CCs) corresponding to multiple serving cells for which the communication device has acquired/monitored system information needed to initiate connection establishment. When CA is configured, the communication device has only one Radio Resource Control (RRC) connection with the network. At RRC connection establishment/re-establishment or handover, one serving cell provides non-access stratum (NAS) mobility information, such as tracking area identification information. One serving cell provides a security input at RRC connection (re-) establishment or handover. This cell is called a primary serving cell (PCell) and the other cells are called secondary serving cells (scells). Depending on the capabilities of the communication device, the SCell may be configured to form a set of serving cells under CA with the PCell. In the downlink, the carrier corresponding to the PCell is a downlink primary component carrier (DL PCC), and in the uplink, it is an uplink primary component carrier (UL PCC). The SCell needs to be configured by the network using RRC signaling before use in order to provide the necessary information to the communication device, such as DL radio carrier frequency and Physical Cell Identity (PCI) information. An SCell that has provided such necessary information to a communication device is referred to as a configured cell for the communication device. The information available at the communication device after cell configuration is particularly sufficient to perform cell measurements. After cell configuration for power saving, the configured SCell is in a deactivated state. When the SCell is deactivated, the communication device does not monitor/receive, among other things, a Physical Dedicated Control Channel (PDCCH) or an Enhanced Physical Dedicated Control Channel (EPDCCH) or a Physical Downlink Shared Channel (PDSCH) in the SCell. In other words, the communication device cannot communicate in the SCell after cell configuration and needs to activate the SCell before data transmission from/the communication device can be initiated in the SCell. LTE provides mechanisms for activating and deactivating scells to a communication device via a Media Access Control (MAC) control element.

A communication system may be configured to support simultaneous communication with two or more access nodes. In LTE, this mechanism is referred to as Dual Connectivity (DC). More specifically, a communication device may be configured in LTE to communicate with a master enb (menb) and a secondary enb (senb). The MeNB may generally provide access to a macro cell, while the SeNB may provide access to a relatively small cell, such as a pico cell, on a different radio carrier. Only the MeNB maintains a connection with a Mobility Management Entity (MME) via the S1-MME interface for the communication device in the DC mode, i.e. only the MeNB is involved in mobility management procedures related to the communication device in the DC mode. LTE supports two different user plane architectures for DC mode communication devices. In a first architecture (split bearer), only the MeNB is connected to the serving gateway (S-GW) via the S1-U interface, and user plane data is transferred from the MeNB to the SeNB via the X2 interface. In a second architecture, the SeNB is directly connected to the S-GW, and the MeNB does not involve the transmission of user-plane data to the SeNB. DC reuse in LTE is related to the radio interface concept introduced for CA in LTE. A first group of cells, referred to as a Master Cell Group (MCG), may be provided by the MeNB for the communication device and may include one PCell and one or more scells, and a second group of cells, referred to as a Secondary Cell Group (SCG), may be provided by the SeNB and may include a master SCell (pscell) having similar functionality as the PCell in the MCG, e.g. with respect to uplink control signaling from the communication device. The second set of cells may also include one or more scells.

Future networks such as 5G may gradually integrate data transmission of different radio technologies in the communication between one or more access nodes and the communication device. Thus, the communication device may be capable of simultaneous operation on more than one radio access technology, and carrier aggregation and dual connectivity may not be limited to the use of radio carriers of only one radio access technology. Instead, aggregation of radio carriers according to different radio access technologies and concurrent communication on such aggregated carriers may be supported.

Due to the ever increasing use of communication equipment and data, small cells such as pico cells may be deployed gradually in future radio access networks to match the ever increasing demand for system capacity. The integration of radio access technologies and/or a large number of small cells may enable the communication device to detect more and more cells in future networks, which are suitable candidates for establishing a connection. Enhancements in carrier aggregation and dual connectivity mechanisms may be needed to fully utilize these cells in future radio access networks. Such enhancements may allow aggregation of a large number of radio carriers, e.g., up to 32, at the communication device, and in particular integration of radio carriers operating over unlicensed spectrum.

Aggregation of radio carriers for communication to/from a communication device and simultaneous communication with two or more access nodes may be particularly useful for operating a cell on an unlicensed (license-exempt) spectrum. A wireless communication system may be permitted to operate in a particular frequency spectrum band. In addition to licensed bands, technologies such as LTE may operate in unlicensed bands. LTE operation in unlicensed spectrum may be based on an LTE Carrier Aggregation (CA) framework, where one or more low-power secondary cells (scells) operate in unlicensed spectrum and may support downlink-only or both Uplink (UL) and Downlink (DL) transmissions, while a primary cell (PCell) may operate in licensed spectrum. The cell may operate in an LTE Frequency Division Duplex (FDD) mode or an LTE Time Division Duplex (TDD) mode.

Two proposals for operation in unlicensed spectrum are LTE Licensed Assisted Access (LAA) and LTE in unlicensed spectrum (LTE-U). The LTE-LAA specified in 3GPP as part of Rel 13 and LTE-U defined by the LTE-U forum may imply maintaining a connection with a licensed band when using an unlicensed band. Furthermore, licensed and unlicensed bands may operate together using, for example, carrier aggregation or dual connectivity. For example, carrier aggregation between a primary cell (PCell) on a licensed band and one or more secondary cells (scells) on an unlicensed band may be applied, and uplink control information of the scells is transmitted in the PCell on the licensed spectrum.

In an alternative proposal, stand-alone operation using only the unlicensed carrier may be used. In standalone operation, at least some of the functions for accessing cells on unlicensed spectrum in these cells and data transmission in these cells are performed with no or only minimal assistance or signaling support from the licensed-based spectrum. Dual connectivity operation for unlicensed bands may be considered as an example of a scenario with minimal assistance or signaling from licensed based spectrum.

Unlicensed band technologies may need to comply with certain rules, e.g., clear channel assessment procedures such as Listen Before Talk (LBT), in order to provide fair coexistence between LTE and other technologies such as Wi-Fi and between LTE operators. In certain jurisdictions, corresponding rules may be defined in the regulations.

In LTE-LAA, a user or access node (such as eNodeB) may need to perform a Clear Channel Assessment (CCA) procedure, such as Listen Before Talk (LBT), before being allowed to transmit, depending on rules or regulatory requirements. A user or access node may monitor a given radio frequency, i.e., carrier, for example, for a short period of time to ensure that the spectrum has not been occupied by some other transmission. The requirements for CCA procedures such as LBT vary according to geographical area: for example in the united states, there is no such requirement, whereas in europe and japan, for example, network elements operating on unlicensed bands need to comply with LBT requirements. Further, CCA procedures such as LBT may be needed to guarantee coexistence with other unlicensed band usage, e.g., to enable fair coexistence with Wi-Fi operating on the same spectrum and/or carrier. After a successful CCA procedure, a user or access node is allowed to start transmitting within a transmission opportunity. The maximum duration of the transmission opportunity may be pre-configured or may be signaled in the system and may extend within a range of, for example, 4 to 13 milliseconds. An access node may be allowed to schedule Downlink (DL) transmissions from and Uplink (UL) transmissions to the access node within a particular time window. If the time between a DL transmission and a subsequent UL transmission is less than or equal to a predetermined value, the uplink transmission may not undergo a CCA procedure such as LBT. Furthermore, certain signaling rules, such as the Short Control Signaling (SCS) rule defined by ETSI for europe, may allow transmission of control or management information without LBT operation if the duty cycle of the related signaling does not exceed a certain threshold, e.g., 5%, e.g., 50ms, within a specified time period. For example, the above-described SCS rules may be used by compatible communication devices, referred to as operating in an adaptive mode, for managing and controlling the corresponding SCS transmission of frames without sensing whether the channel has other signals present. The term "adaptive mode" is defined in ETSI as a mechanism by which a device can adapt its environment by identifying other transmissions present in the band and address the general requirement for efficient operation of the communication system on unlicensed bands. Furthermore, if the time between a DL transmission from an access node and a subsequent UL transmission is less than or equal to a predetermined value, the scheduled UL transmission may typically be allowed without LBT, and the access node has performed an explicit channel assessment procedure, e.g., LBT, prior to the DL transmission. The total transmission time covering the DL transmission and the subsequent UL transmission may be limited to a maximum burst or channel occupancy time. For example, a maximum burst or occupancy time may be specified by the regulator.

Data transmission or/and clear channel assessment procedures cannot be performed on the unlicensed band according to a predetermined schedule in the communication system. Instead, the communication device and the access node need to determine the appropriate time window for uplink and/or downlink transmissions. The respective time window may include one or more Transmission Time Intervals (TTIs), such as subframes in LTE, and is referred to hereinafter as an uplink transmission opportunity or a downlink transmission opportunity. The TTI is a time period reserved in a scheduling algorithm for performing data transmission of a dedicated data unit in a communication system. The determination of the uplink transmission opportunity and/or the downlink transmission opportunity may be based on parameters related to the communication system, such as a configuration mode that governs the sequence of uplink and downlink transmissions in the system. The determination may also be based on rules or rules specifying minimum and/or maximum allowed lengths for uplink transmissions and/or downlink transmissions. The determination of uplink and downlink opportunities may be based in particular on the result of a clear channel assessment procedure, and the communication device or access node will start data transmission on the frequency band only after assessing that the frequency band is clear, i.e. not occupied by data transmissions from other communication devices or access nodes. Further rules or rules may govern the transmission of data in communications between the access node and one or more communication devices. For example, the rules may specify a maximum length of a time window in a communication covering at least one transmission in a first direction, e.g., in a DL from an access node of a cell in a cellular system, and at least one subsequent transmission in a reverse direction, e.g., in an UL, from one or more communication devices in the cell. Such a time window comprising one or more DL and UL transmissions may be referred to as a communication opportunity. The DL transmission may include scheduling information that may be transmitted on a DL control channel. The scheduling information may be used, inter alia, to schedule one or more UL data transmissions and/or one or more DL data transmissions within the current one or more future communication opportunities.

The scheduling information for the data transmission indicates an assignment of the content attribute, the format attribute, and the mapping attribute to the data transmission. The mapping attributes relate to one or more channel elements allocated to transmissions on the physical layer. The details of the channel elements depend on the radio access technology and may depend on the type of channel used. A channel element may refer to a set of resource elements, with each resource element referring to a frequency attribute, such as a subcarrier index (and corresponding frequency range) in a system employing Orthogonal Frequency Division Multiplexing (OFDM), and a time attribute, such as a transmission time of an OFDM or single carrier FDMA symbol. The channel elements may also relate to code attributes, such as an overlay code or a spreading code, which may allow parallel data transmission on the same set of resource elements. Illustrative examples of channel elements in LTE are Control Channel Elements (CCEs) on the Physical Downlink Control Channel (PDCCH) or Enhanced Physical Downlink Control Channel (EPDCCH), PUCCH resources on the Physical Uplink Control Channel (PUCCH), and Physical Resource Blocks (PRBs) on the Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH). It should be appreciated that each data transmission is associated with a code attribute of an assigned channel element and a frequency and time attribute of a resource element in the assigned channel element. The format attribute relates to the processing of a set of information bits in a transmission prior to mapping to an assigned channel element. The format properties may include, inter alia, the modulation and coding scheme used in the transmission and the length of the transport block in the transmission. The content attributes relate to user/payload information conveyed by the transport. In other words, a content attribute is any information that may ultimately affect the arrangement of the detected data sequence at the receiving end in an application. The content attributes may include the sender and/or the recipient of the transmission. The content attribute may also relate to information bits processed in the transmission, e.g. a certain sequence number in the communication. The content attribute may particularly indicate whether the transmission is a retransmission or is related to a new set of information bits. In case of a hybrid automatic repeat request (HARQ) scheme, the content attributes may specifically include an indication of the HARQ process number, i.e. the HARQ specific sequence number, the Redundancy Version (RV) used in the transmission, and the New Data Indicator (NDI).

The scheduling information for data transmission need not include assignment information for the complete set of attributes required in the data transmission. At least a portion of the attributes may be preconfigured, e.g., by semi-persistent scheduling, and may be used for more than one data transmission. Some of the attributes may be implicitly signaled or may be derivable, for example, from timing information. However, dynamic scheduling in more complex systems such as cellular mobile networks requires the transmission of scheduling information on the DL control channel. In a system employing carrier aggregation, DL scheduling information related to a specific data transmission may be transmitted on a component carrier other than the data transmission. The transmission of data and scheduling information on different component carriers is referred to as cross-carrier scheduling.

In a cell operating on unlicensed spectrum, a communication device may begin monitoring channel elements related to a DL control channel carrying scheduling information after detecting a DL data burst or subframe in the cell. The detection of the DL data burst or subframe may be based on the detection of a certain signal in the cell, e.g., a reference signal, such as a cell reference signal that the communication device may blindly detect, or on explicit signaling (e.g., common DCI) indicating the presence of the DL data burst. Monitoring channel elements related to the DL control channel may include blind detection of scheduling information destined for the communication device. The control channel may be a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH) or similar channel as specified in LTE. The communication device may also detect DL data transmissions on a data channel, such as a Physical Downlink Shared Channel (PDSCH) or similar channel, based on the detected scheduling information.

The communication device may need to monitor DL transmissions to detect paging messages. Paging messages are used in particular in mobile communication systems for network initiated connection establishment when the terminal is in IDLE mode, such as RRC IDLE mode in LTE. The location of the paged communication device may not be known to the network at the cell level, so the paging message may be sent in a wider network area. In LTE, this wider network area is called the tracking area. The tracking area in LTE comprises a group of cells and a communication device in RRC IDLE mode needs to register its current tracking area, i.e. the tracking area comprising the cell in which the communication device currently resides, with the network. The paging message may be sent on a dedicated channel or on a shared data channel. A downlink control channel, such as a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH) in LTE, may be used to inform one or more communication devices in a cell of a transmitted paging message. The communication device may use a specific identifier such as P-RNTI in LTE to search for corresponding scheduling information for the downlink control channel. For reasons of economy, the transmission of paging messages in a cell may support Discontinuous Reception (DRX), where the communication device remains in sleep mode most of the time and wakes up only at predetermined times to detect or search for paging messages. In particular, a paging message destined for one or more communication devices may be transmitted from an access node during a paging occasion or paging occasion window.

The paging occasions or paging occasion windows may occur according to a pre-configured configuration or a predetermined configuration. For example, in LTE, the communication device wakes up in one radio frame of the DRX cycle. The system frame number of the radio frame depends on the International Mobile Subscriber Identity (IMSI) of the communication device. Within this radio frame, the communication device checks the subframe, which also depends on the IMSI. This subframe is referred to as a paging occasion in LTE. If the communication device is in subframe scheduling information addressed to the P-RNTI on the PDCCH or EPDCCH, the communication device processes a paging message transmitted in the subframe. Specific communication devices sharing the same paging occasion may be addressed in LTE by identity information (S-TMSI or IMSI) in the paging message.

In systems operating on unlicensed spectrum, if the transmission including the potential paging message is affected by the results of the CCA procedure at the access node, as opposed to LTE, there is no way to ensure the time instance at which the paging message is actually transmitted from the access node. Instead, the access node will defer transmission bursts including potential paging messages until the CCA procedure indicates a clear DL channel. Thus, the paging occasion window may be used in a system that extends a length sufficient to accommodate potential transmission delays. On the other hand, DL transmissions from access nodes in a paging occasion window need not contain paging messages, or paging messages may be transmitted in only a portion of a transmission burst. Thus, monitoring transmission bursts over the entire paging occasion window may result in useless power consumption in the communication device. Preferably, the communication device in idle mode monitors DL transmissions from the access node only when and if a paging message is transmitted in a paging occasion window.

Therefore, there is a need for a mechanism in a system that employs a CCA procedure that ensures that the active period of a communication device in idle mode is reduced during a paging occasion window.

Disclosure of Invention

In a first aspect, there is provided a method comprising: detecting, at a user equipment, a downlink transmission in a selected cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure; determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a detected downlink transmission; and monitoring downlink transmissions for receiving a paging message destined for the user equipment for the duration of the paging detection window or until the paging message is received, whichever occurs first.

The method may further comprise: receiving first configuration information of a paging detection window in broadcast information provided in a mobile communication system, and storing the first configuration information.

The first configuration information may be cell-specific configuration information.

The first configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The method may also include receiving and storing second configuration information for a paging detection window.

The second configuration information may be user-specific configuration information.

The second configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The method may also include using information from the second configuration information if the second configuration information is available.

In an embodiment of the method according to the first aspect, the user equipment may be in an idle mode.

In a second aspect, there is provided a method comprising: causing a downlink transmission from an access node in a cell of the mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure; determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a downlink transmission; and causing transmission of a paging message to the user equipment within the paging detection window.

The method may further include causing transmission of first configuration information of a paging detection window to the user equipment in broadcast information provided in the mobile communication system.

The first configuration information may be cell-specific configuration information.

The first configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The method may also include causing transmission of second configuration information for a paging detection window to the user equipment.

The second configuration information may be user-specific configuration information.

The second configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The method may also include using information from the second configuration information if the second configuration information is available.

In an embodiment of the method according to the second aspect, the user equipment may be in an idle mode.

In a third aspect, an apparatus is provided that includes at least one processor; at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: detecting, at a user equipment, a downlink transmission in a selected cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure; determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a detected downlink transmission; and monitoring downlink transmissions for receiving a paging message destined for the user equipment for the duration of the paging detection window or until the paging message is received, whichever occurs first.

The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to: receiving first configuration information of a paging detection window in broadcast information provided in a mobile communication system, and storing the first configuration information.

The first configuration information may be cell-specific configuration information.

The first configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to receive and store second configuration information for a paging detection window.

The second configuration information may be user-specific configuration information.

The second configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus to: if the second configuration information is available, information from the second configuration information is used.

In an embodiment of the apparatus according to the third aspect, the user equipment may be in an idle mode.

In a fourth aspect, an apparatus is provided that includes at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a downlink transmission; and causing transmission of a paging message to the user equipment within the paging detection window.

The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus to: causing transmission of first configuration information of a paging detection window to a user equipment in broadcast information provided in a mobile communication system.

The first configuration information may be cell-specific configuration information.

The first configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus to: causing transmission of second configuration information for a paging detection window to the user equipment.

The second configuration information may be user-specific configuration information.

The second configuration information may include at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of a paging detection window.

The at least one memory and the computer program code may be configured to, with the at least one processor, cause the apparatus to: if the second configuration information is available, information from the second configuration information is used.

In an embodiment of the apparatus according to the fourth aspect, the user equipment may be in an idle mode.

In a fifth aspect, there is provided an apparatus comprising means for performing a method according to an embodiment of the first aspect.

In a sixth aspect, there is provided an apparatus comprising means for performing a method according to an embodiment of the second aspect.

In a seventh aspect, there is provided a computer program embodied on a non-transitory computer readable storage medium, the computer program comprising program code for controlling execution of a process, and the process comprising: detecting, at a user equipment, a downlink transmission in a selected cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure; determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a detected downlink transmission; and monitoring downlink transmissions for receiving a paging message destined for the user equipment for the duration of the paging detection window or until the paging message is received, whichever occurs first.

In an eighth aspect, there is provided a computer program embodied on a non-transitory computer readable storage medium, the computer program comprising program code for controlling execution of a process, and the process comprising: causing a downlink transmission from an access node in a cell of the mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure; determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a downlink transmission; and causing transmission of a paging message to the user equipment within the paging detection window.

In a ninth aspect, there is provided a computer program product for a computer comprising software code portions for performing the steps of the method according to an embodiment of the first aspect.

In a tenth aspect, a computer program product for a computer is provided, comprising software code portions for performing the steps of the method according to an embodiment of the second aspect.

In an eleventh aspect, a mobile communication system is provided, comprising at least one apparatus according to the third aspect and at least one apparatus according to the fourth aspect.

In a twelfth aspect, a mobile communication system is provided, comprising at least one apparatus according to the fifth aspect and at least one apparatus according to the sixth aspect.

In the foregoing, a number of different embodiments have been described. It is to be understood that other embodiments may be provided by a combination of any two or more of the embodiments described above.

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 shows a schematic diagram of an example communication system comprising a base station and a plurality of communication devices;

FIG. 2 shows a schematic diagram of an example mobile communication device;

FIG. 3 illustrates an example method for a mobile communication device receiving a paging message;

fig. 4 illustrates an example method for an access node sending a paging message;

fig. 5 shows a schematic diagram illustrating the transmission of a paging message according to a first example of the present invention;

fig. 6 shows a schematic diagram illustrating transmission of a paging message according to a second example of the present invention;

fig. 7 shows a diagram illustrating transmission of a paging message according to a third example of the present invention;

FIG. 8 shows a schematic diagram of an example control apparatus.

Detailed Description

Before explaining examples in detail, certain general principles of wireless communication systems and mobile communication devices are briefly explained with reference to fig. 1-2 to assist in understanding the underlying technology of the described examples.

In a wireless communication system 100 such as that shown in fig. 1, wireless access for mobile communication devices or User Equipments (UEs) 102, 104, 105 is provided via at least one base station or similar wireless transmitting and/or receiving node or point. The base stations are typically controlled by at least one suitable controller means to enable operation thereof and management of the mobile communications devices communicating with the base stations. The controller device may be located in a radio access network (e.g., the wireless communication system 100) or a Core Network (CN) (not shown) and may be implemented as one central device, or its functions may be distributed over multiple devices. The controller means may be part of the base station and/or provided by a separate entity such as a radio network controller. In fig. 1, the control means 108 and 109 are shown as controlling the respective macro base stations 106 and 107. The control means of the base station may be interconnected with other control entities. The control device typically has a memory capacity and at least one data processor. The control means and functions may be distributed between a plurality of control units. In some systems, the control means may additionally or alternatively be provided in a radio network controller.

However, the LTE system can be considered to have a so-called "flat" architecture, without providing an RNC; instead, (e) NB communicates with a system architecture evolution gateway (SAE-GW) and a Mobility Management Entity (MME), which may also be aggregated, meaning that multiple such nodes may serve (a set of) multiple (e) NBs. Each UE is served by only one MME and/or S-GW at a time, and (e) the NB keeps track of the current association. The SAE-GW is an "advanced" user plane core network element in LTE, which may be comprised of an S-GW and a P-GW (serving gateway and packet data network gateway, respectively). The functions of the S-GW and the P-GW are separate and they need not be co-located.

In fig. 1, base stations 106 and 107 are shown connected to a wider communications network 113 via a gateway 112. Further gateway functionality may be provided to connect to another network.

Small scale base stations 116, 118, and 120 may also be connected to network 113, for example, through separate gateway functions and/or via controllers of macro-scale stations. Base stations 116, 118, and 120 may be pico or femto base stations, and the like. In this example, stations 116 and 118 are connected via gateway 111, while station 120 is connected via controller device 108. In some embodiments, a small station may not be provided. Small scale base stations 116, 118, and 120 may be part of a second network, such as a WLAN, and may be WLAN APs.

A possible mobile communication device will now be described in more detail with reference to fig. 2, which fig. 2 shows a schematic partial cut-away view of a communication device 200. Such communication devices are commonly referred to as User Equipment (UE) or terminals. Suitable mobile communication devices may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a Mobile Station (MS) or mobile device (such as a mobile phone) or so-called "smart phone", a computer or other wireless interface appliance provided with a wireless interface card (e.g. a USB dongle), a Personal Data Assistant (PDA) or a tablet with wireless communication capabilities, or any combination of these, etc. Mobile communication devices may provide, for example, for carrying data such as voice, electronic mail (email), text messages, multimedia and the like communications. Thus, many services can be provided and offered to users via their communication devices. Non-limiting examples of such services include two-way or multi-way calls, data communication or multimedia services or simply access to a data communication network system such as the internet. Broadcast or multicast data may also be provided to the user. Non-limiting examples of content include downloads, television and radio programs, videos, advertisements, various alerts, and other information.

The mobile device 200 may receive signals over the air or radio interface 207 via appropriate means for receiving and may transmit signals via appropriate means for transmitting radio signals. In fig. 2, the transceiver device is schematically designated by block 206. The transceiver means 206 may be provided, for example, by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged inside or outside the mobile device.

A mobile device is typically provided with at least one data processing entity 201, at least one memory 202 and possibly other components 203 for software and hardware assisted execution of tasks it is designed to perform, including control of access to and communication with access systems and other communication devices. Data processing, storage and other related control devices may be provided in an appropriate circuit board and/or chipset. This feature is denoted by reference numeral 204. The user may control the operation of the mobile device by means of a suitable user interface, such as a keypad 205, voice commands, a touch sensitive screen or touch pad, combinations thereof or the like. A display 208, a speaker, and a microphone may also be provided. Furthermore, the mobile communication device may comprise suitable connectors (wired or wireless) to other devices and/or for connecting external accessories thereto, e.g. a hands-free device.

The communication devices 102, 104, 105 may access the communication system based on various access technologies, such as Code Division Multiple Access (CDMA) or wideband CDMA (wcdma). Other non-limiting examples include Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), and various schemes thereof, such as Interleaved Frequency Division Multiple Access (IFDMA), single carrier frequency division multiple access (SC-FDMA), and Orthogonal Frequency Division Multiple Access (OFDMA), Spatial Division Multiple Access (SDMA), and the like. Signaling mechanisms and procedures may be provided with the help of LTE networks that may enable a device to address in-device coexistence (IDC) issues caused by multiple transceivers. The plurality of transceivers may be configured to provide radio access to different radio technologies.

An example of a wireless communication system is the architecture standardized by the third generation partnership project (3 GPP). The latest 3 GPP-based development is commonly referred to as Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology. The various development stages of the 3GPP specifications are referred to as releases. Recent developments in LTE are commonly referred to as LTE-advanced (LTE-a). LTE employs a mobile architecture known as evolved universal terrestrial radio access network (E-UTRAN). The base stations of such systems are referred to as evolved or enhanced node bs (enbs) and provide E-UTRAN features to the communication devices, such as user plane packet data convergence/radio link control/medium access control/physical layer protocol (PDCP/RLC/MAC/PHY) and control plane Radio Resource Control (RRC) protocol terminals. Other examples of radio access systems include those provided by base stations of systems based on technologies such as Wireless Local Area Network (WLAN) and/or WiMax (worldwide interoperability for microwave access). A base station may provide coverage for an entire cell or similar radio service area.

As described above, there is a need for a mechanism in a system that employs a CCA procedure that ensures that the active period of a communication device in idle mode is reduced during a paging occasion window.

Such a mechanism may include the determination of a page detection window within a paging time window. The paging detection window may be determined based on configuration information relative to the start of a DL data burst within the paging timer window.

It can be seen that an advantageous effect of this mechanism is that a communication device in idle mode only needs to activate its transceiver means in a paging occasion window until it detects the start of a DL data burst and further within the determined paging detection window, or until it has detected a paging message in a paging detection window and within the determined paging detection window.

Fig. 3 illustrates an example method for a communication device receiving a paging message.

In step 310, the communication device detects DL transmissions in a selected cell of the mobile communication system within a paging occasion window. The DL transmission may be subject to a successful clear channel assessment procedure at the access node. The paging occasion window may include two or more transmission time intervals, e.g., 10 subframes in an LTE based system. The method proceeds to step 320.

In step 320, the communications device determines a paging detection window within the paging occasion window relative to the start of the detected DL transmission. The paging detection window may be determined based on received or predetermined or preconfigured configuration information. The method proceeds to step 330.

In step 330, the communication device monitors DL transmissions for receipt of paging messages within a paging detection window. The communication device may monitor for DL transmissions for the duration of the paging detection window, or until the paging message is received, whichever occurs first.

Fig. 4 illustrates an example method for an access node sending a paging message.

In step 410, the access node sends a DL transmission in a cell of the mobile communication system within a paging occasion window. The DL transmission may be subject to a successful clear channel assessment procedure at the access node. The paging occasion window may include two or more transmission time intervals, e.g., 10 subframes in an LTE based system. The method proceeds to step 420.

In step 420, the access node determines a paging detection window within the paging occasion window relative to the start of the DL transmission. The paging detection window may be determined based on predetermined or preconfigured configuration information or configuration information signaled to the communication device. The method proceeds to step 430.

At step 430, the access node sends a paging message to the communication device within the paging detection window determined at step 420.

The determination of the paging detection window in steps 320 and 420 may be based on the first configuration information. The first configuration information may be broadcast in the communication system, e.g. in system information in a cell of the communication system, such as in a System Information Block (SIB) in LTE.

The first configuration information may be a cell-specific configuration and may apply to all communication devices camping on a cell, i.e. all communication devices in idle mode monitoring system information in a cell after cell selection.

The first configuration information may include an indication indicating a length of a paging detection window. Paging information may be sent with high priority within a paging occasion window, and once an access node gains access to a channel, the access node may send a paging message within a paging occasion window. Thus, it may be sufficient to specify only the length field in the configuration information, and the start of the paging detection window may be aligned with the start of the DL transmission in the paging occasion window. Alternatively or additionally, the first configuration information may include an indication indicating a start of a paging detection window relative to a start of a DL transmission in a paging occasion window. Such offset information provides additional flexibility. For example, the offset information may be used to transmit updated system information in a paging occasion window prior to transmitting the paging message.

The determination of the paging detection window in steps 320 and 420 may additionally or alternatively be based on the second configuration information. The communication device may have received the second configuration information on a dedicated channel, for example, before it was set to idle mode.

Thus, the second configuration information may be a user-specific configuration and may apply to a communication device or a group of communication devices residing on a cell.

The second configuration information may include an indication indicating a length of the paging detection window. Alternatively or additionally, the second configuration information may include an indication indicating a start of a paging detection window relative to a start of a DL transmission in a paging occasion window. For example, the offset information may be used to distribute paging messages over a paging occasion window regardless of identity information of the communication device, such as IMSI in LTE.

The second configuration information may be used for transmission of paging messages to the communication device, if available, while the first configuration information may provide only a default configuration.

Fig. 5 shows a schematic diagram illustrating the transmission of a paging message according to a first example of the present invention. The paging occasion window 510 extends over TTIs 0 to 9, e.g., subframes 0 to 9 in a radio frame in an LTE based system. The length of the paging detection window 512 is set to 3 TTIs. The paging detection window starts at TTI 0, i.e. the CCA procedure at the access node is successful in TTI 0, and the access node starts a DL transmission in TTI 0. The paging message is received and detected by the communication device in TTI1 in the paging detection window 512. After successful detection of the paging message in TTI1, the communication device deactivates its transceiver means. In other words, the communication device wakes up for page detection in TTI 0 and remains active until TTI1 and page detection in TTI1 before it deactivates its transceiver device and returns to sleep mode. The communication device may enter a random access procedure, e.g., in TTI 6, in response to the detected paging message.

Fig. 6 shows a schematic diagram illustrating transmission of a paging message according to a second example of the present invention. The paging occasion window 610 extends over TTIs 0 to 9, e.g., subframes 0 to 9 in a radio frame in an LTE based system. The length of the paging detection window 612 is set to 3 TTIs. The paging detection window starts at TTI 2, i.e. the CCA procedure fails in TTI 0 and TTI1, and passes only in TTI 2 at the access node. The access node starts DL transmission in TTI 2. The communication device searches for DL transmissions in TTIs 0 and 1 and searches for paging messages in TTIs 2, 3, and 4. Obviously, no paging message is detected in TTIs 2 and 3, and the communication device remains active for the entire length of the paging detection window. Whether or not a paging message is detected in TTI 4, the communication device returns to sleep mode in TTI 5. In other words, before it deactivates its transceiver device and returns to sleep mode, the communication device wakes up in TTI 0 for page detection and remains active until TTI 4 and page detection in TTI 4. In the event that a paging message is detected in TTI 4, the communications device may enter a random access procedure, for example, in TTI 9.

Fig. 7 shows a diagram illustrating transmission of a paging message according to a third example of the present invention. The paging occasion window 710 extends over TTIs 0 to 9, e.g., subframes 0 to 9 in a radio frame in an LTE based system. The CCA procedure at the access node fails in TTI 0 and DL transmissions start only in TTI 1. The paging detection window 712 is offset from the start of the DL transmission by five TTIs, starting in TTI 6 and extending over three TTIs. In other words, the communication device searches for DL transmissions in TTIs 0 and 1 and returns to sleep mode in TTIs 2 to 5 after the start of DL transmission has been detected in the paging occasion window. The communication device wakes up again in TTI 6, detects a paging message in TTI 6 and returns to sleep mode after TTI 6. In other words, the communication device wakes up for page detection in TTIs 0 and 6 and remains active for page detection in TTI 1. In response to the detected paging message, the communication device may enter a random access procedure.

It should be understood that each block of the flowchart illustrations of the figures, and any combination thereof, may be implemented by various means, such as hardware, software, firmware, one or more processors and/or circuits, or any combination thereof.

The method may be implemented on a mobile device as described in relation to fig. 2, or on a control device as shown in fig. 8. Fig. 8 shows an example of a control device for a communication system, e.g. a station coupled to and/or for controlling an access system, such as a RAN node, e.g. a base station, (e) node B or 5G AP, a node of a central unit or core network of a cloud architecture, such as an MME or S-GW, a scheduling entity, or a server or host. The method may be implanted in a single control device or in more than one control device. The control means may be integrated with or external to a node or module of the core network or RAN. In some embodiments, the base station comprises a separate control device unit or module. In other embodiments, the control apparatus may be another network element, such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control device as well as a control device provided in the radio network controller. The control means 300 may be arranged to provide control of communications in the service area of the system. The control device 300 comprises at least one memory 301, at least one data processing unit 302, 303 and an input/output interface 304. Via the interface the control means may be coupled to the receiver and the transmitter of the base station. The receiver and/or transmitter may be implemented as a radio front end or a remote radio head. For example, the control device 300 may be configured to execute appropriate software code to provide control functions. The control function may include providing and using configuration information for the paging detection window.

It is to be understood that these means may comprise or be coupled to other units or modules or the like, such as a radio part or radio head, for use in or for transmitting and/or receiving. Although the apparatus has been described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

Note that although embodiments have been described with respect to LTE networks, similar principles may be applied with respect to other networks and communication systems, e.g. 5G networks. Thus, although certain embodiments are described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable form of communication system than those shown and described herein.

It is also noted herein that while the above describes exemplifying embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Embodiments of the invention may be implemented by computer software executable by a data processor of a mobile device, such as in a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs, also referred to as program products, including software routines, applets and/or macros, may be stored in any device-readable data storage medium and they include program instructions to perform particular tasks. The computer program product may comprise one or more computer-executable components configured to perform the embodiments when the program is run. The one or more computer-executable components may be at least one software code or portion thereof.

Further in this regard it should be noted that any block of the logic flows as in the figures may represent a program step, or an interconnected logic circuit, block and function, or a combination of a program step and a logic circuit, block and function. The software may be stored on physical media such as memory chips or memory blocks implemented within the processor, magnetic media such as hard or floppy disks, and optical media such as DVDs and data variants CDs thereof. The physical medium is a non-transitory medium.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processor may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), FPGAs, gate level circuits and processors based on a multi-core processor architecture, as non-limiting examples.

Embodiments of the invention may be practiced in various components such as integrated circuit modules. The design of integrated circuits is basically a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiments of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention, which is defined in the appended claims. Indeed, there is another embodiment that includes a combination of one or more embodiments with any other embodiments previously discussed.

Claims (40)

1. A method, comprising:

detecting, at a user equipment, a downlink transmission in a selected cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure;

determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a detected downlink transmission; and

monitoring the downlink transmission for receiving a paging message destined for the user equipment for the duration of the paging detection window or until the paging message is received, whichever occurs first.

2. The method of claim 1, further comprising: receiving first configuration information of the paging detection window in broadcast information provided in the mobile communication system, and storing the first configuration information.

3. The method of claim 2, wherein the first configuration information is cell-specific configuration information.

4. The method of any of claims 2 to 3, wherein the first configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

5. The method of any of claims 1 to 4, further comprising: receiving and storing second configuration information of the paging detection window.

6. The method of claim 5, wherein the second configuration information is user-specific configuration information.

7. The method of any of claims 5 to 6, wherein the second configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

8. The method of any of claims 5 to 7, further comprising: using information from the second configuration information if the second configuration information is available.

9. The method according to any of claims 1 to 8, wherein the user equipment is in idle mode.

10. A method, comprising:

causing a downlink transmission from an access node in a cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure;

determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of the downlink transmission; and

causing transmission of a paging message to the user equipment within the paging detection window.

11. The method of claim 10, further comprising: causing transmission of first configuration information of the paging detection window to the user equipment in broadcast information provided in the mobile communication system.

12. The method of claim 11, wherein the first configuration information is cell-specific configuration information.

13. The method of any of claims 11 to 12, wherein the first configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

14. The method of any of claims 10 to 13, further comprising: causing transmission of second configuration information for the paging detection window to the user equipment.

15. The method of claim 14, wherein the second configuration information is user-specific configuration information.

16. The method of any of claims 14 to 15, wherein the second configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

17. The method of any of claims 14 to 16, further comprising: using information from the second configuration information if the second configuration information is available.

18. The method according to any of claims 10 to 17, wherein the user equipment is in idle mode.

19. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

detecting, at a user equipment, a downlink transmission in a selected cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure;

determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of a detected downlink transmission; and

monitoring the downlink transmission for receiving a paging message destined for the user equipment for the duration of the paging detection window or until the paging message is received, whichever occurs first.

20. The apparatus of claim 19, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus at least to perform:

receiving first configuration information of the paging detection window in broadcast information provided in the mobile communication system;

and storing the first configuration information.

21. The apparatus of claim 20, wherein the first configuration information is cell-specific configuration information.

22. The apparatus according to any of claims 20 to 21, wherein the first configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

23. The apparatus of any of claims 19 to 22, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to receive and store second configuration information for the paging detection window.

24. The apparatus of claim 23, wherein the second configuration information is user-specific configuration information.

25. The apparatus according to any of claims 23 to 24, wherein the second configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

26. The apparatus of any of claims 23 to 25, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to: using information from the second configuration information if the second configuration information is available.

27. The apparatus according to any of claims 19 to 26, wherein the user equipment is in idle mode.

28. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to perform at least the following:

causing a downlink transmission from an access node in a cell of a mobile communication system within a paging timer window comprising two or more transmission time intervals, wherein the downlink transmission is subject to a clear channel assessment procedure;

determining a paging detection window comprising one or more transmission time intervals within the paging timer window relative to a start of the downlink transmission; and

causing transmission of a paging message to the user equipment within the paging detection window.

29. The apparatus of claim 28, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to: causing transmission of first configuration information of the paging detection window to the user equipment in broadcast information provided in the mobile communication system.

30. The apparatus of claim 29, wherein the first configuration information is cell-specific configuration information.

31. The apparatus according to any of claims 29 to 30, wherein the first configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

32. The apparatus according to any of claims 28 to 31, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to: causing transmission of second configuration information for the paging detection window to the user equipment.

33. The apparatus of claim 32, wherein the second configuration information is user-specific configuration information.

34. The apparatus according to any of claims 32 to 33, wherein the second configuration information comprises at least one of:

-information indicating the length of the paging detection window, and

-information indicating the start of the paging detection window.

35. The apparatus according to any of claims 32 to 34, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to: using information from the second configuration information if the second configuration information is available.

36. The apparatus according to any of claims 28 to 35, wherein the user equipment is in idle mode.

37. An apparatus comprising means for performing the method of any of claims 1-9.

38. An apparatus comprising means for performing the method of any of claims 10-18.

39. A computer program product for a computer, comprising software code portions for performing the steps of any one of claims 1 to 9 or any one of claims 10 to 18 when said product is run on the computer.

40. A mobile communication system comprising at least one apparatus according to claim 19 or claim 37 and at least one apparatus according to claim 28 or 38.