RU2808614C2 - Improved two-stage initiation procedure - Google Patents

Abstract

FIELD: radio scheduling.

SUBSTANCE: invention is related to scheduling using uplink radio resources. The UE receives a first stage uplink resource scheduling message from a radio base station indicating uplink radio resources in order to perform uplink transmission through an unlicensed cell. Additionally, a second stage uplink resource scheduling message that is associated with the first stage scheduling message is received. Upon receiving the second stage resource scheduling message, the UE processor determines that uplink transmission is scheduled if the first stage uplink resource scheduling message is valid. The first stage uplink resource scheduling message is determined to be valid based on determining whether or not uplink transmission is initiated by another second stage uplink resource scheduling message within a predetermined period of time before receiving the second stage uplink resource scheduling message. The UE then performs uplink transmission.

EFFECT: making it possible to prevent multiple initiation of uplink transmissions in an environment with multiple UE terminals.

10 cl, 12 dwg

Description

field of technology to which the invention relates

The present disclosure relates to a user equipment for scheduling using uplink radio resources and to a method for operating the user equipment.

State of the art

Long Term Evolution (LTE) standard

Third generation (3G) mobile systems based on WCDMA radio access technology are being deployed on a large scale around the world. The first stage of improvement or development of this technology entails the introduction of High Speed Downlink Packet Access (HSDPA) and enhanced Uplink, also called "High Speed Uplink Packet Access (HSUPA)", which provides a very competitive radio access technology.

To prepare for ever-increasing user demands and remain competitive with new radio access technologies, 3GPP is introducing a new mobile communications system called Long Term Evolution (LTE). LTE is designed to meet the carrier needs for high-speed data and multimedia transport and high-bandwidth voice support for the next decade.

The specification of working studies (WI) in the Long Term Evolution (LTE) standard, called "UMTS Enhanced Terrestrial Radio Access (UTRA)" and "UMTS Enhanced Terrestrial Radio Access Network (UTRAN)", is completed as Release 8 (LTE Rel. 8). The LTE system introduces efficient packet-switched radio access and radio access networks that provide full IP-based functionality with low latency and low costs. In LTE, multiple scalable transmission bandwidths such as 1.4, 3.0, 5.0, 10.0, 15.0 and 20.0 MHz are specified to achieve flexible system deployment using this spectrum. In the downlink, orthogonal frequency division multiplexing (OFDM) radio access is suited due to its inherent resistance to multipath interference (MPI) due to low symbol rate, use of cyclic prefix (CP) and affinity with different bandwidth arrangements transfers. Single carrier frequency division multiple access (SC-FDMA) radio access is adapted in the uplink since providing global coverage is prioritized over increasing the peak data rate given the limited transmission power of the user equipment (UE). Many key packet switched radio access technologies are used, including multiple-input multiple-output (MIMO) technologies, and a highly efficient control signaling structure is achieved in LTE Rel. 8/9.

LTE architecture

The general LTE architecture is shown in FIG. 1. E-UTRAN consists of an enhanced Node B providing user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) end nodes of the E-UTRA standard for the user equipment (UE). The enhanced node B (eNB) hosts the physical layer (PHY), media access control (MAC), radio link control (RLC), and packet data control protocol (PDCP) layers, which include header compression and user plane encryption functionality. It also offers radio resource control (RRC) functionality consistent with the control plane. It performs many functions, including radio resource management, access control, scheduling, ensuring consistent uplink quality of service (QoS), cell information broadcast, user plane and control plane data encryption/decryption, and downlink user plane packet header compression/decompression. /uplink. The advanced B nodes are connected to each other via an X2 interface.

The Evolved Node Bs are also connected via the S1 interface to the EPC (Evolved Packet Switching Core), more specifically to the MME (Mobility Management Entity) via S1-MME and to the Serving Gateway (SGW) via S1-U. The S1 interface maintains a many-to-many relationship between the MME/Serving Gateways and the Advanced Node Bs. The SGW routes and forwards user data packets, also acting as a mobility anchor for the user plane during handoffs between the Advanced Node Bs and the as a mobility anchor between LTE and other 3GPP technologies (for terminating the S4 interface and for relaying traffic between 2G/3G systems and PDN GW). For user equipments in the idle state, the SGW terminates the downlink data path and initiates a paging when downlink data arrives for the user equipment. It manages and stores subscriber device contexts, such as IP bearer service parameters or internal network routing information. It also replicates user traffic in the event of legitimate interception.

The MME is the key management node for the LTE access network. It regulates the subscriber device's idle mode tracking and paging procedures, including retransmissions. It is involved in the bearer activation/deactivation process and also regulates the selection of SGW for the subscriber unit during initial attachment and during intra-LTE handover involving core network (CN) node relocation. It regulates user authentication (through interaction with HSS). Non-Access Layer (NAS) signaling is terminated at the MME, and it also regulates the generation and allocation of temporary identities for subscriber devices. It checks the subscriber device's authorization to join the service provider's public land mobile network (PLMN) and enforces the subscriber device's roaming restrictions. The MME is the endpoint on the network for encryption/integrity protection for NAS service signaling and handles security key management. Lawful interception of service signals is also supported through MME. The MME also provides a control plane function for mobility between LTE and 2G/3G access networks with an S3 interface terminated in the MME from the SGSN. The MME also completes the S6a interface to its own HSS for roaming subscriber devices.

Component carrier structure in LTE

The downlink component carrier of a 3GPP LTE system is divided in the time-frequency domain into so-called subframes. In 3GPP LTE, each subframe is divided into two downlink slots, as shown in FIG. 2, wherein the first downlink slot contains a control channel area (PDCCH area) in the first OFDM symbols. Each subframe consists of a given number of time domain OFDM symbols (12 or 14 OFDM symbols in 3GPP LTE (Rev. 8)), with each OFDM symbol covering the full bandwidth of the component carrier. OFDM symbols therefore consist of a certain number of modulation symbols transmitted on the corresponding subcarriers. In LTE, the transmitted signal in each time slice is described by a grid of resources in subcarriers and OFDM symbols. is the number of resource blocks in the bandwidth. Quantity depends on the downlink transmission bandwidth configured in the cell and must satisfy , Where =6 and =110 respectively represent the smallest and largest downlink bandwidths supported by the current version of the specification. is the number of subcarriers in one resource block. For a subframe structure with a regular cyclic prefix, =12 and .

Under the condition of a multi-carrier communication system, for example using OFDM, which is, for example, used in the 3GPP Long Term Evolution (LTE) standard, the smallest unit of resources that can be assigned by the scheduler is one “resource block”. A physical resource block (PRB) is defined as successive OFDM symbols in the time domain (eg, 7 OFDM symbols) and successive subcarriers in the frequency domain, as illustrated in FIG. 2 (for example, like 12 subcarriers for a component carrier). In 3GPP LTE (Release 8), a physical resource block therefore consists of resource elements corresponding to one slot in the time domain and 180 kHz in the frequency domain (for further information on the downlink resource grid, see for example the 3GPP document TS 36.211, "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)", current version 12.6.0, section 6.2, available at http://www.3gpp.org and contained herein document at the link).

One subframe consists of two time slices, so that there are 14 OFDM symbols per subframe when so-called “normal” CP (cyclic prefix) is used, and 12 OFDM symbols per subframe when so-called “extended” CP is used. For the sake of terminology, hereinafter, time-frequency resources equivalent to identical consecutive subcarriers spanning a complete subframe are referred to as a “resource block pair,” or equivalently, a “RB pair” or a “PRB pair.” The term "component carrier" means a combination of several resource blocks in the frequency domain. In future versions of LTE, the term "component carrier" will no longer be used; instead, the terminology changes to "cell", which means a combination of downlink and optionally uplink resources. The connection between the downlink resource carrier and the uplink resource carrier is indicated in system information transmitted over the downlink resources.

Similar assumptions for the component carrier structure also apply to subsequent versions.

Carrier aggregation in LTE-A to support higher bandwidth

The frequency spectrum for the enhanced IMT standard was determined at the World Radiocommunication Conference 2007 (WRC-07). Although the full frequency spectrum for the enhanced IMT standard is defined, the actual available frequency bandwidth differs according to each region or country. However, according to the decision on the available frequency spectrum structure, standardization of the air interface has been started in the Third Generation Partnership Project (3GPP).

The bandwidth that an advanced LTE system can support is 100 MHz, while an LTE system can only support 20 MHz. Currently, the shortage of radio frequency spectrum is becoming a bottleneck in the development of wireless networks, and as a result, it is difficult to find a spectrum band that is wide enough for an advanced LTE system. Therefore, there is an urgent need to find a way to obtain a wider bandwidth of the radio frequency spectrum, with carrier aggregation functionality being a possible answer.

In carrier aggregation, two or more component carriers are aggregated in order to support wider transmission bandwidths up to 100 MHz. Multiple cells in an LTE system are aggregated into one wider channel in the system under the enhanced LTE standard, which is wide enough for 100 MHz, even though these cells in LTE may be in different frequency bands. All component carriers can be configured to be LTE Rel. 8/9 compatible, at least when the component carrier bandwidth does not exceed the supported bandwidth of LTE Rel. 8/9-cell. Not all component carriers aggregated by a subscriber unit may necessarily be Rel. 8/9 compatible. Existing mechanisms (eg, denial) can be used to prevent Rel-8/9 subscriber devices from being pinned to the component carrier.

A subscriber unit can simultaneously receive or transmit on one or more component carriers (corresponding to multiple serving cells) depending on its characteristics. Subscriber LTE-A Rel. 10-device with reception and/or transmission characteristics for carrier aggregation can simultaneously receive and/or transmit on multiple serving cells, while the subscriber's LTE Rel. An 8/9 device can receive and transmit on only one serving cell, provided that the component carrier structure adheres to Rel. 8/9 specifications.

Carrier aggregation is supported for contiguous and non-contiguous component carriers, with each component carrier limited to a maximum of 110 frequency domain resource blocks using 3GPP LTE numerology (Release 8/9).

A 3GPP LTE-A (Release 10)-compliant subscriber device can be configured with the ability to aggregate a different number of component carriers originating from an identical advanced Node B (base station), and possibly with different uplink and downlink bandwidths. The number of downlink component carriers that can be configured depends on the downlink aggregation capabilities of the UE. On the other hand, the number of uplink component carriers that can be configured depends on the aggregation capabilities in the uplink of the UE. Currently, it may not be possible to configure a mobile terminal with a greater number of uplink component carriers compared to downlink component carriers. In a typical TDD deployment, the number of component carriers and the bandwidth of each component carrier in the uplink and downlink are identical. Component carriers originating from an identical advanced Node B need not necessarily provide identical coverage.

The separation between the center frequencies of continuously aggregated component carriers shall be a multiple of 300 kHz. This serves to ensure compatibility with the 100 kHz frequency pattern for 3GPP LTE (Release 8/9) while maintaining the orthogonality of the subcarriers with 15 kHz spacing. Depending on the aggregation scenario, nx300 kHz spacing may be simplified by inserting a low number of unused subcarriers between adjacent component carriers.

The nature of multi-carrier aggregation is revealed only up to the MAC layer. For the uplink and downlink, one HARQ object is required in the MAC for each aggregated component carrier. There is (in the absence of SU-MIMO for the uplink) at most one transport block per component carrier. The transport block and its potential HARQ retransmissions must be translated on an identical component carrier.

When carrier aggregation is configured, the mobile terminal has only one RRC connection to the network. During RRC connection establishment/re-establishment, one cell provides security input (one ECGI, one PCI and one ARFCN) and mobility information at a non-granting layer (eg, TAI), similar to LTE Rel. 8/9. After the RRC connection is established/re-established, the component carrier corresponding to this cell is referred to as a downlink primary cell (PCell). One and only one downlink PCell (DL PCell) and one uplink PCell (UL PCell) are always configured per subscriber unit in the connected state. In the configured set of component carriers, other cells are referred to as secondary cells (SCells), where the SCells are a secondary downlink component carrier (DL SCC) and a secondary uplink component carrier (UL SCC). A maximum of five serving cells including PCells can currently be configured for one UE.

Configuration and reconfiguration, as well as addition and removal, of component carriers can be performed via RRC. Activation and deactivation is carried out, for example, via MAC control elements. During intra-LTE handover, the RRC may also add, remove, or reconfigure SCells for use in the target cell. When a new SCell is added, dedicated RRC signaling is used to send SCell system information, with the information required for transmission/reception (same as version 8/9 for handover). Each SCell is configured with a serving cell index when the SCell is added to one UE; The PCell always has index 0 of the serving cell.

When a user equipment is configured with carrier aggregation, there is at least one pair of uplink and downlink component carriers that are always active. The downlink component carrier of this pair may also be referred to as a "DL anchor carrier". The same applies also for the uplink. When carrier aggregation is configured, a subscriber unit can be scheduled on multiple component carriers simultaneously, but at most one random access procedure must be executed at any time. Cross carrier scheduling allows the PDCCH of a component carrier to schedule resources on another component carrier. For this purpose, a component carrier identification field called "CIF" is introduced in the corresponding DCI (Downlink Control Information) formats.

The association established by transmitting RRC signaling between the uplink and downlink component carriers enables identification of the uplink component carrier for which transmission grant applies when cross-carrier scheduling is not present. The association of downlink component carriers with an uplink component carrier does not necessarily have to be one-to-one. In other words, more than one downlink component carrier may be associated with an identical uplink component carrier. At a time, a downlink component carrier can communicate with only one uplink component carrier.

Uplink/downlink scheduling

The MAC function in the enhanced Node B refers to scheduling by which the eNB allocates available radio resources in one cell among UEs and between radio bearers for each UE. In principle, the enhanced Node B allocates downlink and uplink resources to each UE, respectively, based on downlink data buffered in the enhanced Node B and based on buffer status reports (BSRs) received from the UE. In this process, the advanced Node B considers the QoS requirements of each configured radio bearer and selects the MAC PDU size.

The conventional scheduling mode is dynamic scheduling through downlink grant/assignment (DCI) messages for allocating downlink transmission resources and uplink grant/assignment messages for allocating uplink transmission resources. They are transmitted on the Physical Downlink Control Channel (PDCCH) using the Cell Radio Network Temporary Identifier (C-RNTI) to identify the intended UE. In addition to dynamic scheduling, persistent scheduling is specified which allows the UE to semi-statically configure and allocate radio resources over a period of time greater than one subframe, thereby eliminating the need for specific downlink assignment messages or uplink grant messages. by PDCCH for each subframe. To configure or reconfigure a persistent schedule, RRC signaling indicates a resource allocation interval in which radio resources are periodically assigned. When the PDCCH is used to configure or reconfigure a persistent schedule, it is necessary to distinguish scheduling messages that apply to a persistent schedule from scheduling messages used for dynamic scheduling. For this purpose, a special scheduling identification is used, known as the semi-persistent scheduling C-RNTI (SPS-C-RNTI), which is different for each UE from the C-RNTI used for dynamic scheduling messages.

To inform scheduled users regarding their allocation status, transport format, and other transmission-related information (eg, HARQ information, transmit power control (TPC) commands), L1/L2 control overhead signals are transmitted on the downlink along with the data. L1/L2 control overhead signals are multiplexed with downlink data in a subframe, provided that the user allocation may change between subframes. It should be noted that user allocation can also be performed on a TTI (Transmission Time Interval) basis, where the TTI length can be a multiple of the number of subframes. The TTI length may be fixed across the service area for all users, may vary between users, or may even be dynamic for each user. Typically, L1/2 control overhead only needs to be transmitted once per TTI. Without loss of generality, it is further assumed that the TTI is equivalent to one subframe.

L1/L2 control overhead signals are transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH carries the message as downlink control information (DCI), which in most cases includes resource assignments and other control information for the mobile terminal or groups of UEs. In general, multiple PDCCHs may be transmitted in one subframe.

Downlink control information occurs in several formats that differ in overall size as well as in the information contained in their fields. The various DCI formats currently specified for LTE are listed below and are described in detail in 3GPP TS 36.212 "Multiplexing and channel coding", section 5.3.3.1 (current version v12.6.0 available at http://www.3gpp. org and is contained in this document by reference). For further information regarding DCI formats and the specific information that is carried in DCI, please refer to the technical standard mentioned or to "LTE - The UMTS Long Term Evolution - From Theory to Practice", Edited by Stefanie Sesia, Issam Toufik, Matthew Baker , Chapter 9.3, contained in this document by reference. Additional formats may be added in the future.

Layer 1/Layer 2 control overhead transmission

To inform scheduled users regarding their allocation status, transport format, and other transmission-related information (eg, HARQ information, transmit power control (TPC) commands), L1/L2 control overhead signals are transmitted on the downlink along with the data. L1/L2 control overhead signals are multiplexed with downlink data in a subframe, provided that the user allocation may change between subframes. It should be noted that user allocation can also be performed on a TTI (Transmission Time Interval) basis, where the TTI length can be a multiple of the number of subframes. The TTI length may be fixed across the service area for all users, may vary between users, or may even be dynamic for each user. Typically, L1/2 control overhead only needs to be transmitted once per TTI. Without loss of generality, it is further assumed that the TTI is equivalent to one subframe.

L1/L2 control overhead signals are transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH carries the message as downlink control information (DCI), which in most cases includes resource assignments and other control information for the mobile terminal or groups of UEs. In general, multiple PDCCHs may be transmitted in one subframe.

It should be noted that in 3GPP LTE, assignments for uplink data transmissions, also called “uplink scheduling grants” or “uplink resource assignments,” are also transmitted on the PDCCH. In addition, 3GPP Release 11 introduces EPDCCH, which performs a function essentially identical to that of PDCCH, i.e. transmits L1/L2 control overhead even if the detailed transmission methods differ from the PDCCH. More detailed information is contained in the current versions of 3GPP TS 36.211 and 36.213, contained in this document by reference. Therefore, most of the elements given in the Background Section and in the embodiments apply to the PDCCH as well as the EPDCCH or other L1/L2 control signal transmission medium unless expressly stated otherwise.

Typically, information sent in L1/L2 control overhead signaling for assigning uplink or downlink radio resources (specifically LTE(-A) release 10) can be classified into the following elements:

- User credentials indicating the user to whom the allocation is being made. It is typically included in the checksum by masking the CRC with the user's identity;

- Resource allocation information indicating the resources (eg, resource blocks, RBs) on which the user is allocated. Alternatively, this information is called "resource block assignment (RBA)". It should be noted that the number of RBs to which a user is allocated may be dynamic;

- Carrier indicator , which is used if the control channel transmitted on the first carrier assigns resources that concern the second carrier, i.e. resources on the second carrier or resources associated with the second carrier (cross-carrier scheduling);

- Modulation and coding scheme , which determines the modulation scheme used and the coding rate;

- HARQ information , for example new data indicator (NDI) and/or backup version (RV), which is particularly useful when retransmitting data packets or parts thereof;

- Power control commands to regulate the transmission power of designated uplink data transmissions or control information;

- Reference signal information , for example, the applied cyclic shift and/or orthogonal coverage code index to be used for transmitting or receiving reference signals associated with the assignment;

- Uplink or downlink assignment index , which is used to identify the order of assignments, which is particularly useful in TDD systems;

- Frequency hopping information , for example, an indicator regarding whether or not and how resource frequency hopping should be applied in order to increase frequency diversity;

- CSI request , which is used to initiate the transmission of channel state information on a designated resource; And

- Multi-cluster information , which is a flag used to indicate and control whether a transmission occurs in a single cluster (in a contiguous set of RBs) or in multiple clusters (in at least two non-contiguous sets of contiguous RBs). Multi-cluster allocation is introduced through 3GPP LTE-(A) version 10.

It should be noted that the above list is non-exhaustive and not all of the information elements mentioned must necessarily be present in every PDCCH transmission depending on the DCI format that is used.

Downlink control information occurs in several formats, which differ in overall size as well as in the information contained in their fields, as mentioned above. The following are some of the DCI formats currently defined for LTE. More detailed information is provided in the 3GPP technical standard TS 36.212 v14.0.0, in particular in section 5.3.3.1 "DCI formats", contained in this document by reference.

- Format 0: DCI Format 0 is used to transmit resource grants for PUSCH, using transmissions on one antenna port in uplink mode 1 or 2 transmissions.

- Format 1: DCI Format 1 is used to convey resource assignments for PDSCH transmissions on a single codeword basis (downlink transmission modes 1, 2 and 7).

- Format 1A: DCI Format 1A is used to compactly signal resource assignments for PDSCH transmissions on a single codeword basis and to allocate a dedicated preamble signature to the mobile terminal for non-contentious random access (for all transmission modes).

- Format 1B: DCI Format 1B is used to compactly signal resource assignments for PDSCH transmissions using closed-loop precoding with transmission rank 1 (downlink transmission mode 6). The information transmitted is identical to the information in format 1A, but with the addition of a precoding vector indicator used for PDSCH transmission.

- Format 1C: DCI format 1C is used for very compact transmission of PDSCH assignments. When 1C format is used, PDSCH transmission is limited to using QPSK modulation. It is used, for example, to signal paging messages and broadcast system information messages.

- 1D Format: The 1D DCI format is used to compactly signal resource assignments for PDSCH transmission using multi-user MIMO. The transmitted information is identical to the information in format 1B, but instead of one of the precoding vector indicator bits, one bit is provided to indicate whether or not a power offset is applied to the data symbols. This indication is required to indicate whether transmit power is shared or not between two UEs. Future versions of LTE may extend this to the case of power sharing among more UEs.

- Format 2: DCI Format 2 is used to transmit resource assignments for the PDSCH for closed-loop MIMO operation (transmission mode 4).

- Format 2A: DCI Format 2A is used to convey resource assignments for PDSCHs for open-loop MIMO operation. The transmitted information is identical to that for format 2, except that if the enhanced Node B has two transmit antenna ports, there is no precoding information, and for four antenna ports, two bits are used to indicate the transmission rank (transmit mode 3) .

- Format 2B: introduced in Release 9 and is used to transmit resource assignments for PDSCH for two-level beamforming (transmission mode 8).

- Format 2C: Introduced in Release 10 and used to transmit resource assignments for PDSCHs for single-user or multi-user closed-loop MIMO operation with a maximum of 8 layers (transmission mode 9).

- 2D format: introduced in version 11 and used for transmissions with up to 8 levels; mainly used for COMP (Cooperative Multipoint Transmission) (transmission mode 10)

- Format 3 and 3A: DCI formats 3 and 3A are used to transmit power control commands for PUCCH and PUSCH with 2-bit or 1-bit power control, respectively. These DCI formats contain separate power control commands for a group of UEs.

- Format 4: DCI Format 4 is used for PUSCH scheduling using closed-loop spatial multiplexing mode 2 uplink transmissions.

- Format 5: DCI Format 5 is used for PSCCH (Physical Sidelink Control Channel) scheduling and also contains several SCI Format 0 fields used for PSSCH (Physical Shared Sidelink Control Channel) scheduling. If the number of DCI format 5 information bits mapped to a given search space is less than the format 0 payload size for scheduling an identical serving cell, zeros must be added to format 5 until the payload size is equal to the format 0 payload size , which includes all the padding bits added to format 0.

LTE in unlicensed bands: licensed auxiliary access (LAA)

In September 2014, 3GPP initiated a new case study on LTE operation in unlicensed spectrum. The reason for LTE's expansion into unlicensed frequency bands is the ever-increasing demand for wireless broadband data coupled with the limited number of licensed frequency bands. Consequently, unlicensed spectrum is increasingly being seen by cellular operators as a complementary tool to expand their service offerings. One advantage of LTE in unlicensed spectrum bands compared to being based on other radio access technologies (RATs) such as Wi-Fi is that complementing the LTE platform with access over unlicensed spectrum provides the opportunity for operators and manufacturers to leverage existing or planned investments in LTE/EPC hardware in the radio network and core network.

However, it should be taken into account that access over unlicensed spectrum can never match the quality of access over licensed spectrum due to the inevitable sharing with other radio access technologies (RATs) in unlicensed spectrum, such as Wi-Fi. LTE operation in unlicensed frequency bands should therefore, at least initially, be considered complementary to LTE in licensed spectrum, rather than stand-alone operation in unlicensed spectrum. Based on this assumption, 3GPP defines the term "Licensed Ancillary Access (LAA)" for LTE operation in unlicensed frequency bands in combination with at least one licensed frequency band. However, future standalone LTE operation in unlicensed spectrum, i.e. without assistance through licensed cells should not be excluded. Enhanced Licensed Ancillary Band Access (eLAA) is an improvement to LAA, particularly also using unlicensed spectrum in the uplink. The efficient use of unlicensed spectrum to complement licensed spectrum has the potential to bring greater benefits to service providers and, ultimately, to the wireless industry as a whole. To take full advantage of LTE operation in unlicensed spectrum, it is critical to define a full UL access scheme in addition to the already defined DL access scheme.

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

A very simple scenario is illustrated in FIG. 4, with a licensed PCell, a licensed SCell 1, and various unlicensed SCells 2, 3 and 4 (roughly illustrated as small cells). The unlicensed SCell 2, 3 and 4 transceiver network nodes may be remote radio heads controlled by the eNB, or they may be nodes that join the network but are not controlled by the eNB. For simplicity, the connection of these nodes to the eNB or to the network is not explicitly shown in the drawing.

Currently, the basic approach envisaged in 3GPP is that a PCell should operate in a licensed frequency band, while one or more SCells should operate in unlicensed frequency bands. One advantage of this strategy is that PCell can be used to reliably transport control messages and user data with strict Quality of Service (QoS) requirements, such as voice and video, whereas SCell in unlicensed spectrum can result in, depending on the scenario, to some significant reduction in QoS due to inevitable sharing with other RATs.

It is agreed that the LAA will focus on the unlicensed 5 GHz frequency bands. One of the most critical issues due to this is sharing with Wi-Fi (IEEE 802.11) systems operating in these unlicensed frequency bands. To support fair sharing between LTE and other technologies such as Wi-Fi, as well as to ensure fairness between different LTE operators in an identical unlicensed frequency band, LTE channel access for unlicensed frequency bands must adhere to certain sets of regulatory rules that may partially vary by geographic region and specific frequency band; For a comprehensive description of the regulatory requirements for all regions for operation in the unlicensed 5 GHz frequency bands, see R1-144348, “Regulatory Requirements for Unlicensed Spectrum,” Alcatel-Lucent et al., RAN1#78bis, September 2014, contained herein. document at the link, as well as in the 3GPP technical report 36.889, current version 13.0.0. Depending on the region and frequency band, regulatory requirements that must be considered when designing LAA procedures include Dynamic Frequency Selection (DFS), Transmit Power Control (TPC), Listen Before You Talk (LBT), and Intermittent Transmission with a limited maximum transmission duration. 3GPP's intention is to target one global infrastructure for LAA, which essentially means that all requirements for different regions and 5 GHz frequency bands must be taken into account for system design.

For example, in Europe certain limits are set for the nominal channel bandwidth, as is evident from section 4.3 of the European standard ETSI EN 301 893, current version 1.8.1, contained herein by reference. The nominal channel bandwidth is the widest frequency band that includes the guard bands assigned to a single channel. The occupied bandwidth of a channel is the bandwidth containing 99% of the signal power. The device is allowed to operate in one or more contiguous or non-contiguous channels simultaneously.

Listen Before You Talk (LBT) is defined as a mechanism by which a device applies a Channel State Assessment (CCA) check before using a channel. The CCA uses at least energy detection to determine the presence or absence of other signals on the channel to determine whether the channel is busy or idle, respectively. European and Japanese regulations currently require the use of LBT in unlicensed frequency bands. In addition to regulatory requirements, carrier sensing through LBT is one way to share unlicensed spectrum fairly and is therefore considered a vital feature for fair and convenient operation of unlicensed spectrum in one infrastructure based on a global solution.

In unlicensed spectrum, channel availability cannot always be guaranteed. In addition, certain regions, such as Europe and Japan, prohibit continuous transmissions and impose restrictions on the maximum duration of a transmission burst in unlicensed spectrum. Therefore, intermittent transmission with a limited maximum transmission duration is a required functionality for LAA. DFS is required for certain regions and frequency bands to detect interference from radar systems and eliminate in-channel operation with those systems. Additionally, the intention is to achieve a nearly uniform spectrum load. Operation in DFS mode and the corresponding requirements are associated with the master-slave principle. The master node must detect radar interference; however, may be based on another device associated with the master node in order to implement radar detection.

Operation in unlicensed frequency bands at 5 GHz in most regions is limited to fairly low transmit power levels compared to operation in licensed frequency bands, resulting in small coverage areas. Even if licensed and unlicensed carriers are to be transmitted at identical power, typically an unlicensed carrier in the 5 GHz band is expected to support less coverage than a licensed cell in the 2 GHz band due to increased path loss and mitigation effects of external interference and guidance for the signal. An additional requirement for certain regions and frequency bands is the use of TPC to reduce the average level of interference caused to other devices operating in the same unlicensed frequency band.

Detailed information is contained in the European harmonized standard ETSI EN 301 893, current version 1.8.1, contained in this document by reference.

This European LBT regulation requires devices to perform a channel condition assessment (CCA) before occupying a data radio channel. It is permitted to initiate transmission on an unlicensed channel only after the channel has been detected as idle, for example based on energy detection. In particular, the device must observe the channel for a certain minimum time (e.g. for Europe 20 µs, see ETSI 301 893, according to section 4.8.3) during CCA. A channel is considered busy if the detected energy level exceeds the configured CCA threshold (e.g. for Europe, -73 dBm/MHz, see ETSI 301 893, according to section 4.8.3), and on the other hand is considered idle if The detected power level is below the configured CCA threshold. 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 idle, the device is allowed to transmit immediately. The maximum transmission duration is limited to facilitate fair resource sharing with other devices operating in the same frequency band.

Energy detection for CCA is performed over the entire channel bandwidth (e.g., 20 MHz in the 5 GHz unlicensed frequency bands), meaning that the receive power levels of all LTE OFDM symbol subcarriers in that channel contribute to the estimated energy level in the device that performs CCA.

In addition to the CCA described above, an additional extended CCA (ECCA) may be required to apply if the device is classified as a load-bearing device (LBE) as described in ETSI 301 893, section 4.9.2.2, incorporated herein by reference. ECCA contains additional CCA observation time for a certain duration of a random factor N multiplied by the CCA observation time slice. N specifies the number of unoccupied idle time slots resulting in a total period of inactivity that must be observed before initiating a transfer.

In addition, the total time that a device has transmissions on a given carrier without re-evaluating the availability of that carrier (i.e. LBT/CCA) is specified as the channel busy time (see ETSI 301 893, in accordance with section 4.8.3.1 ). The channel busy time should be in the range of 1-10 ms, while the maximum channel busy time, for example, could be 4 ms, as currently set for Europe. In addition, there is a minimum idle time during which the UE is not allowed to transmit after transmitting on an unlicensed cell, where the minimum idle time is at least 5% of the channel occupied time. At the end of the inactivity period, the UE may perform a new CCA, etc. This transmission behavior is illustrated schematically in FIG. 5, and the drawing is considered from ETSI EN 301 893 (in it, Fig. 2: “Example of timing for Frame Based Equipment”).

Fig. 6 illustrates the timing synchronization between Wi-Fi transmission and LAA UE transmissions in a specific frequency band (unlicensed cell). As can be seen from FIG. 5, after a Wi-Fi burst, a CCA signal-free interval is at least required before the eNB “reserves” an unlicensed cell, for example, by transmitting a reservation signal to the next subframe boundary. Then the actual LAA DL packet begins. This should similarly apply to the LTE UE, which, after successfully executing the CCA, should reserve a subframe by transmitting a reservation signal such that it then begins the actual LAA UL packet.

Uplink scheduling in unlicensed cells

DCI formats 0A, 0B, 4A and 4B are provided for eLAA in such a way as to support uplink transmissions (PUSCH) for single subframe and multiple subframe transmission grants and, respectively, for single and multiple antenna ports.

- DCI format 0A: One subframe, one antenna port

- DCI format 0B: Multiple subframes, one antenna port

- DCI format 4A: One subframe, multiple antenna ports

- DCI format 4B: Multiple subframes, multiple antenna ports

Details regarding these DCI formats are contained in the 3GPP technical standard TS 36.212 v14.0.0, sections 5.3.3.1.1A, 5.3.3.1.1B, 5.3.3.1.8 A, 5.3.3.1.8B, contained in this document by reference .

Any of these DCI formats (ie, uplink grants) may either constitute a single-stage grant or form part of a two-stage grant. In current example implementations in LTE (see TS 36.212), this is reflected by the "PUSCH Trigger A" field, which is a 1-bit field distinguishing whether the received uplink grant is for "uninitiated scheduling" when the bit value is 0 (i.e., represents a one-stage uplink grant) or is for "initiated scheduling" when the bit value is 1 (i.e., represents a two-stage uplink grant) . It may be controlled by the eNB, which is a radio network regulatory entity for scheduling radio resources in the UE.

The two-stage uplink scheduling procedure requires receiving two separate messages ("Trigger A" and "Trigger B") in a specific manner by the UE so as to schedule one uplink transmission.

The A trigger message may be any of the above uplink grants (ie, DCI formats 0A, 0B, 4A, or 4B). In connection with this two-stage transmission permission, the four DCI formats include the following data fields, currently defined in the technical standard TS 36.212 v14.0.0:

" PUSCH flip-flop A: 1 bit, where a value of 0 indicates untriggered scheduling and a value of 1 indicates triggered scheduling, as defined in section 8.0 [3].

- Time offset: 4 bits, as specified in [3].

- When the flag for triggered scheduling is set to 0,

- The field indicates the absolute time offset for PUSCH transmission.

- Otherwise,

- The first two bits of the field indicate the relative timing offset for the PUSCH transmission.

- The last two bits of the field indicate the time window during which PUSCH scheduling via triggered scheduling is valid. "

In addition, the available DCI formats for the A-trigger message also include conventional data fields for indicating radio resources that are scheduled for transmission on the uplink, for example, a "resource block assignment" field, a "modulation and coding scheme" field, field "HARQ process number", etc. In addition, DCI formats 0A, 0B, 4A, 4B (in particular, DCI CRC) can be scrambled with UE-specific identification data (eg, C-RNTI) such that the corresponding uplink grants are addressed in specific UE.

The Trigger B message is in DCI format 1C, currently defined in TS 36.212 v14.0.0, section 5.3.3.1.4, contained herein by reference. The 1C DCI format currently specified in the technical standard for use within the scope of transmissions on an unlicensed carrier, including a two-step procedure for issuing permission to transmit, is as follows:

" Otherwise

- Subframe configuration for LAA: 4 bits as defined in section 13A [3]

- Uplink transmission duration and offset indicator: 5 bits as defined in section 13A [3]. The field only applies to a UE configured with uplink transmission in LAA SCell

- PUSCH flip-flop B: 1 bit, as defined in section 8.0 [3]. The field only applies to a UE configured with uplink transmission in LAA SCell

- Reserved information bits are added until the size is equal to the size of the 1C format used for very compact scheduling of one PDSCH codeword "

The B trigger message (DCI format 1C), when used as described above as part of a two-stage transmit grant procedure, is typically not addressed to a specific UE, but instead to a shared identity (in this case CC-RNTI; common control RNTI, which is the RNTI to be used in the context of providing common PDCCH control information; see 3GPP TS 36.321 v14.0.0 contained herein by reference) can be used by the eNB in order to scramble the 1C DCI format , in particular, its CRC.

Cross-reference [3] in the above references TS 36.212 means the 3GPP technical standard TS 36.213, current version 14.0.0, at least sections 8.0 and 13 of which are relevant for two-stage transfer authorizations and are therefore contained in their entirety herein link.

In particular, section 8 of TS 36.213 specifies in great detail for LAA Scell when and how uplink transmission (i.e. PUSCH) should occur:

" For a serving cell that is an LAA SCell, the UE shall:

- upon detection of a PDCCH/EPDCCH with DCI format 0A/0B/4A/4B and with the "PUSCH Trigger A" field set to "0" in subframe n intended for the UE, or

- when detecting a PDCCH/EPDCCH with DCI format 0A/0B/4A/4B and with the "PUSCH trigger A" field set to "1" in the last subframe relative to subframe n-v intended for the UE, and when detecting a PDCCH with DCI CRC , scrambled by CC-RNTI, and with the "PUSCH flip-flop B" field set to "1" in subframe n,

- perform the corresponding PUSCH transmission, converted and consistent with respect to the channel access procedures described in section 15.2.1, in subframe(s) n+l+k+i with i=0, 1,..., N-1 according to PDCCH/EPDCCH and HARQ process identifier , where N=1 for DCI format 0A/4A, and the value of N is determined by the "number of scheduled subframes" field in the corresponding DCI format 0B/4B.

- The UE is configured with a maximum value of N through the top-level parameter maxNumberOfSchedSubframes-Format0B for DCI format 0B and the top-level parameter maxNumberOfSchedSubframes-Format4B for DCI format 4B;

- the value of k is determined by the scheduling delay field in the corresponding DCI 0A/0B/4A/4B according to Table 8.2d, if the field "PUSCH flip-flop A" is set to "0", or according to Table 8.2e otherwise;

- meaning determined by the HARQ process number field in the corresponding DCI format 0A/0B/4A/4B and ;

- for the field "PUSCH trigger A" set to "0" in the corresponding DCI format 0A/0B/4A/4B,

- l=4

- otherwise:

- the value l is the UL offset defined by the "UL Configuration for LAA" field in the corresponding DCI with the CRC scrambled by CC-RNTI according to the procedure in subclause 13A and the "PUSCH Trigger B" field set to "1" ,

- the value of v is determined by the validation duration field in the corresponding PDCCH/EPDCCH with DCI format 0A/0B/4A/4B according to Table 8.2f and the PUSCH trigger A field set to "1"

- the smallest l+k value supported by the UE is included in the UE-EUTRA characteristics.

Table 8.2d: for DCI format 0A/0B/4A/4B with the "PUSCH Trigger A" field set to "0".

The value of the "scheduling delays" field 0000 0 0001 1 0010 2 0011 3 0100 4 0101 5 0110 6 0111 7 1000 8 1001 9 1010 10 1011 eleven 1100 12 1101 13 1110 14 1111 15

Table 8.2e: for DCI format 0A/0B/4A/4B with the "PUSCH Trigger A" field set to "1".

The value of the "scheduling delays" field 00 0 01 1 10 2 eleven 3

Table 8.2f: for DCI format 0A/0B/4A/4B with the "PUSCH Trigger A" field set to "1".

Validation duration field value 00 8 01 12 10 16 eleven 20

The current 3GPP technical standards therefore specify in great detail how the two-step transmission authorization procedure should be carried out. However, it should be noted that the above definition of two-stage transfer authorization procedures under current standardization is subject to continuous change and improvement and may therefore change in the future. Therefore, the above implementation of a two-stage transfer authorization procedure according to current 3GPP technical standards should be considered merely as an example implementation, with many of the details being less important to the present invention.

However, for the present invention, it is assumed that the basic principle behind the two-step transfer authorization procedure should remain identical, as explained above. In particular, the basic principle is explained in connection with FIG. 7, which illustrates the operation of a two-stage transmit grant including transmitting and receiving DCIs including trigger A and trigger B messages. For the exemplary explanation below, it is assumed that the illustrated subframes are numbered by considering the subframe in which trigger B ( ie, a second stage uplink scheduling message) is received at the UE, as reference subframe n; previous and subsequent subframes are numbered accordingly. It is further assumed that the message with trigger A is received in subframe n-3, and that a time window of length v is specified within which the two-stage transmit grant procedure can be validly performed. In other words, the time window may be viewed as defining a period of time during which a trigger B message can be received so as to actually initiate a corresponding uplink transmission, based on the transmission parameters indicated by the trigger A and/or trigger messages. B.

The length v of the time window may be approximately indicated in the A trigger message, as illustrated above by the last 2 bits of the time offset field of DCI formats 0A, 0B, 4A, 4B in TS 36.212 and Table 8.2.f of TS 36.213.

When a message with trigger B is received in subframe n, the UE must determine whether or not the associated message with trigger A is received by the UE within a time window of length v (starting immediately before receiving the message with trigger B, i.e., ranging from n- 1 to n-v). In the illustrated scenario, the trigger A scheduling message is received in subframe n-3, and thereby within the time window, thereby triggering uplink transmission to the UE. The uplink transmission (ie PUSCH) is then performed at a specific transmission time offset in subframe n+offset. The UE may perform uplink transmission according to information received in the trigger A message and the trigger B message, for example, using specified radio resources and a modulation and coding scheme, etc.

The exact timing of the PUSCH offset is less important to the present invention. As an example, according to the current standardization in TS 36.213, the PUSCH timing offset is “l+k+i”, where the l parameter is set via a message with trigger B (see the “Uplink Transmission Duration and Offset Indicator” field of the DCI -format 1C in TS 36.212 and Table 13A-2 of TS 36.213), where the parameter k is specified by a trigger message (see the first 2 bits of the Time Offset field of any of DCI formats 0A, 0B, 4A and 4B in TS 36.212 , as well as Table 8.2e in TS 36.213). The parameter i is applicable in the case where multiple uplink subframes are scheduled through a two-stage scheduling procedure in the uplink and in this case is from 0 to the number of subframes provided minus 1 (otherwise, it is only 0). Additional information may be taken from section 8 of TS 36.213 above. However, the PUSCH timing offset for performing uplink transmission according to this two-stage uplink scheduling procedure may also be set differently or even predetermined.

As mentioned above, 3GPP specifies a two-stage scheduling procedure for uplink transmissions in unlicensed cells. However, this two-stage planning procedure can be further improved.

The essence of the invention

Non-limiting and exemplary embodiments provide improved methods and subscriber devices provided for scheduling uplink transmissions to be performed by the subscriber devices.

The independent claims provide non-limiting and exemplary embodiments. Preferred embodiments are specified in the dependent claims of the invention.

According to one general aspect, a subscriber device is provided that is adapted to be scheduled with uplink radio resources. The at least one cell is configured to communicate between a subscriber device and a radio base station that is responsible for scheduling uplink radio resources for the cell. The user equipment includes a receiving device that receives from a radio base station a first stage uplink resource scheduling message indicating uplink radio resources available through the user equipment to perform uplink transmissions through a scheduled cell. The receiving device further receives from the radio base station a second stage uplink resource scheduling message that is associated with the first stage uplink resource scheduling message. The user equipment further includes a processor that determines whether the first stage uplink resource scheduling message is valid or not. The processor determines, upon receiving the second stage uplink resource scheduling message, that uplink transmission is scheduled if the processor determines that the first stage uplink resource scheduling message is valid. Therefore, the determination of whether or not a first stage uplink resource scheduling message is valid is based on the determination of whether or not an uplink transmission is initiated by another second stage uplink resource scheduling message within a predetermined period. time before receiving the second stage uplink resource scheduling message. The subscriber device further includes a transmitter that, if the processor determines that uplink transmission is scheduled, performs uplink transmission via the scheduled cell. The cell, for example, may be an unlicensed cell in the context of 3GPP LTE Release 14, or another cell that supports two-stage scheduling.

Accordingly, in another general aspect, the technologies disclosed herein illustrate a method of operating a subscriber unit adapted to schedule uplink radio resources thereon. The at least one unlicensed cell is configured to communicate between a subscriber device and a radio base station that is responsible for scheduling uplink radio resources for the unlicensed cell. The method comprises receiving from a radio base station a first stage uplink resource scheduling message indicating uplink radio resources usable by a subscriber unit to perform uplink transmissions through an unlicensed cell. The method further comprises receiving from the radio base station a second stage uplink resource scheduling message that is associated with the first stage uplink resource scheduling message. The method further comprises determining whether the first stage uplink resource scheduling message is valid or not. The method further comprises determining, upon receiving the second stage uplink resource scheduling message, that uplink transmission is scheduled if it is determined that the first stage uplink resource scheduling message is valid. Therefore, the determination of whether or not a first stage uplink resource scheduling message is valid is based on the determination of whether or not an uplink transmission is initiated by another second stage uplink resource scheduling message within a predetermined period. time before receiving the second stage uplink resource scheduling message. The method further comprises performing uplink transmission through the unlicensed cell if it is determined that uplink transmission is scheduled.

Additional benefits and advantages of the disclosed embodiments will become apparent from the detailed description and drawings. Benefits and/or advantages may be separately provided by various embodiments and features of the detailed description and drawings and do not need to all be provided in order to obtain one or more embodiments and features.

These general and specific aspects may be implemented using a subscriber device and method and a combination of subscriber device and method.

Brief description of drawings

Exemplary embodiments will now be described in more detail with reference to the accompanying drawings.

Fig. 1 shows an exemplary 3GPP LTE system architecture,

Fig. 2 shows an example downlink resource grid for a subframe downlink slot as defined for 3GPP LTE (Release 8/9)

Fig. 3 shows an example uplink resource grid of a subframe uplink slot as defined for 3GPP LTE.

Fig. 4 illustrates an example LAA scenario with multiple licensed and unlicensed cells.

Fig. 5 illustrates the transmission behavior for LAA transmission.

Fig. 6 illustrates the timing synchronization between Wi-Fi transmission and a UE downlink LAA packet for an unlicensed cell.

Fig. 7 approximately illustrates a two-stage uplink scheduling procedure provided for uplink transmissions over unlicensed cells.

Fig. 8 illustrates multiple initiation of uplink transmissions in a multi-UE environment.

Fig. 9 illustrates preventing multiple initiation of uplink transmissions in a multi-UE environment according to a first implementation of the embodiment.

Fig. 10 is a diagram for a two-stage uplink transmission procedure according to a first implementation of the embodiment.

Fig. 11 illustrates preventing multiple initiation of uplink transmissions in a multi-UE environment according to a second implementation of the embodiment, and

Fig. 12 is a diagram for a two-stage uplink transmission procedure according to a second implementation of the embodiment.

Detailed Description of the Invention

A mobile station or mobile node, or user terminal, or subscriber device is a physical object in a communication network. One node can have several functional objects. A functional entity is referred to as a software or hardware module that implements and/or offers a predefined set of functions to other functional entities of a node or network. Nodes may have one or more interfaces that connect the node to a communications facility or medium over which the nodes can exchange data. Likewise, a network entity may have a logical interface that connects the functional entity to a communications facility or medium over which it can communicate with other functional entities or correspondent nodes.

The term "radio resources" when used in a set of claims and in an application should be broadly understood to mean physical radio resources, such as time-frequency resources.

The term "unlicensed cell" or alternatively "unlicensed carrier", when used in a set of claims and in an application, is to be understood broadly as a cell/carrier operating in an unlicensed frequency band, with a specific frequency bandwidth. Accordingly, the term “licensed cell” or alternatively “licensed carrier”, when used in a set of claims and in an application, is to be understood broadly as a cell/carrier operating in a licensed frequency band, with a specific frequency bandwidth. As an example, these terms should be understood in the context of 3GPP from Release 12/13 and the access work study on the licensed ancillary band.

Fig. 8 illustrates a UE that belongs to UE group #1, a UE that belongs to UE group #2, and an enhanced Node B.

It is assumed that trigger A, which is a first stage uplink resource scheduling message, is transmitted from the enhanced Node B to the UE from group #1 in subframe n-2. In this example case, the valid time window for trigger A sent to the UE from group #1 is 5 subframes. Because of this, information regarding the valid time window is provided through trigger A itself.

It is further assumed that trigger B, which is a second stage uplink resource scheduling message, is transmitted from the enhanced Node B in subframe n. Trigger B is received by both UEs from groups #1 and #2, although the enhanced Node B transmits trigger B with an intent that is identical to the second stage uplink resource scheduling message for the already transmitted trigger A (as the first uplink resource scheduling message). stage) to the UE from group #1 in subframe n-2. In this example case, it is assumed that the UEs in group #2 do not receive triggers A within the corresponding valid time window before trigger B. When receiving trigger B, all UEs that have the ability to receive trigger B (which generally include UEs from group #1 as well as from group #2) must check whether or not they accept trigger A within the corresponding valid time window. Therefore, in this example, the UE from group #1 checks whether or not it receives trigger A up to 5 subframes earlier (in this case, from subframe n-5 to subframe n-1). When trigger A is received in subframe n-2, which is within the valid time window, the UE from group #1 then initiates uplink transmission.

Since the UE in group #2 does not receive trigger A, trigger B received in subframe n does not initiate uplink transmission by the UE in group #2.

As is further apparent from FIG. 8, the UE from group #2 receives flip-flop A in subframe n+1. In this example case, the valid time window for trigger A sent to the UE from group #2 is 3 subframes. As shown in more detail in this figure, the second flip-flop B is transmitted from the enhanced Node B (in subframe n+3). The second trigger B is again received by both UEs from groups #1 and #2, although the enhanced Node B transmits the second trigger B with an intent that is identical to the second stage uplink resource scheduling message for trigger A (as an uplink resource scheduling message first stage) transmitted to the UE from group #2 in subframe n+1. When receiving trigger B, the UE from group #2 checks whether or not it has received trigger A up to 3 subframes earlier (in this case, from subframe n to subframe n+2). When the corresponding trigger A is received in subframe n+1, which is within the valid time window, the UE from group #2 then initiates uplink transmission.

However, since the second trigger B is also received at the UE from group #1 in subframe n+3, the UE from group #1 must again check whether or not it receives trigger A up to 5 subframes earlier (in this case, from subframe n-2 to subframe n+2). Considering that the UE from group #1 receives trigger A in subframe n-2, i.e. still within the valid time window for this received trigger A, the UE from group #1 again initiates its second uplink transmission, although the second initiated uplink transmission is not intended by the enhanced Node B to be performed by the UE from group # 1, but instead only through UEs from group #2. According to this exemplary scenario, as shown in FIG. 8, such a second triggered uplink transmission performed by the UE of group #1 should also occur if the second B flip-flop is received in subframe n+2 (instead of received in subframe n+3). Only if the second B flip-flop is received in subframe n+4 or later, multiple uplink transmission initiations should not occur, given an approximate allowable time window of 5 subframes for a UE in group #1.

In general, such multiple uplink transmission initiations are not required in a multi-UE environment. The first reason is that such unwanted uplink transmission carries the risk of interfering with other transmissions in the corresponding subframe. The second reason is that such multiple initiation may imply UL transmission conflict: if a UE from group #1 initiates a UL transmission by trigger B in subframe n, and the corresponding UL transmission is indicated by trigger A to last for 4 subframes, the corresponding UL transmission approximately occurs in subframes n+2 to n+5. If the identical UE from group #1 again initiates a UL transmission by trigger B in subframe n+3, and again the corresponding UL transmission indicated by the identical trigger A must last for 4 subframes, the corresponding UL transmission approximately occurs in subframes n +5 - n+8. As can be seen, the two triggers must therefore cause a conflict for subframe n+5, and it is not clear whether the data should be transmitted as the result of the first trigger B or as the result of the second trigger B: even though the transmission resources may be identical in both cases, the corresponding data in general, must contain various transport blocks or packets. Such conflict should be avoided as it leads to the potential for misunderstanding between the UE and the enhanced Node B.

The following exemplary embodiments are conceived by the inventors in order to alleviate one or more of the problems explained above.

Specific implementations of the various embodiments shall be implemented in the broad specification provided through the 3GPP standards and partially explained in the Background section, with the addition of specific key features further explained with respect to the various implementations of the presented embodiment. It should be noted that the embodiment may advantageously be used, for example, in a mobile communication system, for example, in communication systems according to the 3GPP LTE-A standard (version 11/10/12/13 or subsequent versions), as described in the above section "Layer technology", but the embodiment is not limited to use in these particular exemplary communication networks.

The explanations are not to be understood as limiting the scope of the disclosure, but rather as merely exemplary embodiments in order to better understand the present disclosure. Those skilled in the art will be aware that the general principles of the present disclosure generally set forth in the set of claims and in the explanations set forth in the Summary section of the specification may apply to a variety of scenarios and methods not expressly described below. . For purposes of illustration and explanation, several assumptions are made, which, however, should not unduly limit the scope of the following embodiments.

Moreover, as mentioned above, the following embodiments may be implemented in a 3GPP LTE-A (Rel.12/13 and later) environment. Various embodiments primarily provide the possibility of having an improved uplink transmission scheme. However, other functionality (ie, functionality not changed by different embodiments) may remain exactly the same as that explained in the Background section, or may change without affecting the different embodiments; for example, for functions and procedures specifying how uplink transmission is actually performed (eg, segmentation, modulation, coding, beamforming, multiplexing) and scheduled (PDCCH, DCI, cross-carrier scheduling, self-scheduling), or how conventional uplink transmission time synchronization through the use of a time advance-based procedure is performed (eg, initial time advance, time advance update commands).

Next, a general embodiment for solving the above problem(s) is described in detail, which is explained through the use of the following exemplary scenario designed to easily explain the principles of the embodiment. However, the principles can also be applied to other scenarios, some of which are mentioned below.

The UE begins two-stage uplink resource scheduling. Specifically, resource scheduling is initiated by a first stage uplink resource scheduling message (Trigger A) for the unlicensed cell, which is received by the receiving apparatus UE. Next, a second stage uplink resource scheduling message (trigger B) for the unlicensed cell is received by the receiving apparatus UE.

Next, the UE processor determines whether the first stage uplink resource scheduling message (Trigger A) is valid or not by checking the validity of the first stage uplink resource scheduling messages. Therefore, the determination of the validity of this first stage uplink resource scheduling message (Trigger A) is based on the determination as to whether or not an uplink transmission is initiated by another second stage uplink resource scheduling message (Trigger B) during a predetermined period of time before receiving the second stage uplink resource scheduling message (trigger B).

It is then determined, by the processor, upon receiving the second stage uplink resource scheduling message (trigger B), that uplink transmission is scheduled if the processor determines that the first stage uplink resource scheduling message (trigger A) is acceptable.

Finally, in case the processor determines that uplink transmission is scheduled, the transmitting device UE performs uplink transmission through the unlicensed cell.

This basic principle of the invention, as described above, advantageously provides the ability to prevent multiple initiation of uplink transmissions in a multi-UE environment. Since there is no risk of inadvertently initiating, through a trigger B that is intended for another UE, a second uplink transmission by that particular UE that has already previously initiated an uplink transmission within a valid time window, the upgraded Node B can directly transmit a new trigger A to different UEs immediately after sending trigger B even within a predefined time period/allowable time window.

Due to this, the throughput of the user/cell can be significantly increased. In addition, by eliminating multiple triggering of uplink transmissions, the required amount of overhead for flip-flop A can be reduced since large tolerance times indicated by flip-flop A can be used more efficiently.

In addition, a false alarm of the second B flip-flop after a valid first B flip-flop within the valid time/valid time window does not result in a false PUSCH transmission. This advantageously eliminates the occurrence of errors due to a false alarm trigger B.

Fig. 9 illustrates a first implementation of an embodiment in which multiple initiation of uplink transmissions in a multi-UE environment is prevented.

Fig. 9 essentially illustrates the situation as already described above in connection with FIG. 8, regarding the reception of triggers in UEs from groups #1 and #2. As explained, the UE from group #1 receives flip-flop B in subframe n+3. To eliminate the second initiation of an uplink transmission (which occurs in a conventional system as described in connection with FIG. 8), the UE from group #1 checks whether or not another trigger B has already initiated an uplink transmission in advance. a certain period of time before receiving the B flip-flop received in subframe n+3. Preferably, the predetermined time period is a valid time window, as indicated in the message with trigger A. In the example, the predetermined time period is a valid time window with a length of 5 subframes (as already explained in connection with FIG. 8, in which trigger A notifies the UE regarding the number of subframes (v=5), which denotes a valid time window).

Therefore, the UE of group #1 checks whether or not another trigger B initiates uplink transmission within a time period of 5 subframes before subframe n+3. Specifically, the UE of group #1 checks whether or not another trigger B initiates uplink transmission between subframe n-2 and n+2. As illustrated in FIG. 8, uplink transmission has already been initiated by trigger B received in subframe n. Therefore, to avoid multiple initiations of uplink transmissions within the valid time window for trigger A, for any trigger B received after the first trigger B, which in the example is received in subframe n, the UE ignores trigger A received in subframe n-2 , which should create a valid time window between subframe n-2 and n+2 and which should allow the B flip-flop received in subframe n+3 to initiate another uplink transmission. In particular, ignoring trigger A, which is received in subframe n-2, then prevents trigger B, received in subframe n+3, from triggering an uplink transmission, since a valid time window is not further detected until the trigger is received. B in subframe n+3. It should be noted that the expression "ignore trigger A" in case of detection of a previous uplink transmission initiated within the valid time window for such trigger A means that trigger A received in subframe n-2 is "not considered" for flip-flop B received in subframe n+3.

As a consequence, and as illustrated in FIG. 9, the unwanted second/multiple uplink transmission is not initiated in subframe n+3 by the UE of group #1. Therefore, in this case, only the UE from group #2 initiates uplink transmission via the received trigger B in subframe n+3. By means of the solution, multiple initiation in a multi-UE environment is eliminated/prevented.

Fig. 10 is a diagram for a two-stage uplink transmission procedure according to a first implementation of the embodiment, as already mentioned above in connection with FIG. 9.

In step S101, the UE (any of the UEs from groups #1 and #2) starts two-stage uplink resource scheduling. Specifically, resource scheduling is initiated by a first stage uplink resource scheduling message for an unlicensed cell, which is received by the UE in step S102. Next, a second stage uplink resource scheduling message is received by the UE for the unlicensed cell in step S103.

The validity check of the first stage uplink resource scheduling messages consists of step S104, in which it is determined whether or not the uplink transmission has already been initiated by another second stage uplink resource scheduling message within a time period T before receiving the uplink resource scheduling message. second stage communication lines. Therefore, the "time period T" corresponds to the "predetermined time period before receiving the second stage uplink resource scheduling message" as reflected in the claims, and also corresponds to the "allowable time window" as shown in FIG. 8 and 9.

If it is determined that another uplink transmission has already been completed within the time period T (Yes in step S104), the process proceeds to step S102 with the next round of waiting for a first-stage uplink resource scheduling message.

However, if it is determined in step S104 that another uplink transmission has not been completed within the time period T ("No" in step S104), the process proceeds to step S105, which is associated with determining that the resource scheduling message first stage uplink is valid.

Since the first stage uplink resource scheduling message is valid, the process proceeds to step S106, which is associated with uplink transmission scheduling. Then, in step S107, the uplink transmission is actually performed.

Fig. 11 illustrates a second implementation of an embodiment in which multiple initiation of uplink transmissions in a multi-UE environment is prevented. The second implementation is an alternative to the first implementation; however, multiple initiations of uplink transmissions by an identical UE within a valid time window for trigger A are eliminated by invalidating trigger A instead of simply ignoring trigger A as described in the first implementation.

Refer to the scenario of FIG. 9, in which the second flip-flop B is received by a UE from group #1 in subframe n+3. As an alternative to the first implementation of the embodiment, in the second implementation of the embodiment according to FIG. 11, a UE in group #1 may actively invalidate trigger A (which is received in subframe n-2) upon receiving trigger B in subframe n (invalidation may also be performed in subframe n+1 or n+2, but must be performed before interpretation/analysis/examination of the second flip-flop B in subframe n+3). Therefore, the second trigger B received in subframe n+3 is not able to initiate an uplink transmission to the UE from group #1 because there is no further valid time window for trigger A. In other words, the second implementation of the embodiment actively disables/ invalidates trigger A upon receipt of the first trigger B (or at least until the next trigger B is received) that has already initiated an uplink transmission. Therefore, by actively invalidating/disabling trigger A, thereby removing the valid time window for trigger A, unintentional multiple uplink transmissions cannot be initiated by the UE in group #1.

In general, it should be noted that the second implementation of the embodiment (as per FIG. 11) generally differs from the first implementation (as per FIGS. 9 and 10) by invalidating trigger A (removing the valid time window for trigger A) when initiating the transfer on the uplink via trigger B, instead of simply ignoring trigger A (ignoring the valid time window for trigger A) when receiving the second trigger B, as shown in FIG. 9.

An active "Trigger A invalid/disable", for example, may be implemented by toggling a particular bit in a field that is associated with a first stage uplink transmission resource scheduling message.

Fig. 12 is a diagram for a two-stage uplink transmission procedure according to a second implementation of the embodiment as already mentioned above in connection with FIG. eleven.

In step S101, the UE (any of the UEs from groups #1 and #2) starts two-stage uplink resource scheduling. Specifically, resource scheduling is initiated by a first stage uplink resource scheduling message for an unlicensed cell, which is received by the UE in step S102. Next, a second stage uplink resource scheduling message is received by the UE for the unlicensed cell in step S103.

The validity check of the first stage uplink resource scheduling messages consists of step S108, which determines whether or not the first stage uplink resource scheduling message is invalid. If it is determined that the first stage uplink resource scheduling message is invalid (Yes in step S108), the process proceeds to step S102 with the next cycle of waiting for the first stage uplink resource scheduling message, or to step S103 with waiting for the scheduling message second stage uplink resources.

If it is determined in step S108 that the first stage uplink resource scheduling message is not invalid ("No" in step S108), the process proceeds to step S105, which is associated with determining that the first stage uplink resource scheduling message is acceptable. Then, since the first stage uplink resource scheduling message is valid, the process proceeds to step S106, which is associated with uplink transmission scheduling. Then, in step S107, the uplink transmission is actually performed. Thereafter, the process proceeds to step S109, which is associated with invalidating the first stage uplink resource scheduling message. Thereafter, the process proceeds to step S102 with the next cycle of waiting for the first stage uplink resource scheduling message or to step S103 with waiting for the second stage uplink resource scheduling message.

If, for example, the second stage uplink resource scheduling message is received after the first stage uplink resource scheduling message is invalidated (in step S109), the process proceeds from step S103 to step S108. In step S108, it is determined that the first stage uplink resource scheduling message is invalid so that the process again proceeds to step S102 or to step S103 without performing uplink transmission.

This procedure, as described above, reflects the specific behavior as illustrated in FIG. 11, in which the second flip-flop B in subframe n+3 does not initiate additional uplink transmission because flip-flop A is already invalidated after the first flip-flop B initiates the uplink transmission.

In the above description of the embodiment, two-stage uplink radio resource scheduling is described for a cell of the communication system. It should be noted that such two-stage uplink radio resource scheduling is possible not only for unlicensed or licensed cells, but also for any cells that support two-stage uplink radio resource scheduling.

According to an additional embodiment, which is implemented in the environment of TS 36.213, section 8.0, the standard is proposed to specify:

For a serving cell that is an LAA SCell, the UE shall:

-- upon detection of a PDCCH/EPDCCH with DCI format 0A/0B/4A/4B and with the "PUSCH Trigger A" field set to "0" in subframe n destined for the UE, or

-- upon detection of a PDCCH/EPDCCH with DCI format 0A/0B/4A/4B and with the "PUSCH Trigger A" field set to "1" in the last subframe relative to the nv subframe intended for a UE that is not triggered by the "field" PUSCH flip-flop B" set to "1" in subframe n-v+ 1 and subframe n-1 , and upon detecting a PDCCH with DCI CRC scrambled by CC-RNTI and the PUSCH flip-flop B field set to "1" in subframe n ,

- perform the corresponding PUSCH transmission, converted and consistent with respect to the channel access procedures described in section 15.2.1, in subframe(s) n+l+k+ i with i=0, 1,..., N-1 according to the PDCCH /EPDCCH and [...]

Hardware and Software Implementation of the Present Disclosure

Other exemplary embodiments relate to implementing the various embodiments described above using hardware, software, or software in conjunction with hardware. In this regard, a user terminal (mobile terminal) and an enhanced Node B (base station) are provided. The user terminal and the base station are configured to implement the methods described herein, including corresponding entities that participate appropriately in the methods, such as a receiver, a transmitter, processors.

It should be further recognized that various embodiments may be implemented or performed using computing devices (processors). The computing device or processor, for example, may be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, etc. Various embodiments may also be implemented or implemented by a combination of these devices. In particular, each functional block used in the description of each embodiment described above may be implemented by LSI as an integrated circuit. They may be individually configured as chips, or a single chip may be configured to include some or all of the functional blocks. These may include data input and output associated with them. LSI may be referred to here as IC, system LSI, super-LSI, or ultra-LSI depending on the differences in the degree of integration. However, integrated circuit implementation technology is not limited to LSI and can be implemented through the use of a dedicated circuit or a general purpose processor. In addition, an FPGA (Field Programmable Gate Array) can be used, which can be programmed after the LSI is manufactured, or a reconfigurable processor, in which the connections and settings of the circuit elements located within the LSI can be reconfigured.

Additionally, various embodiments may also be implemented through software modules that are executed by a processor, or directly in hardware. In addition, a combination of software modules and hardware implementation may be possible. Program modules can be stored in any type of computer readable storage media, such as RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc. Additionally, it should be noted that individual features of different embodiments may, individually or in any combination, be the subject of another embodiment.

Those skilled in the art will appreciate that many changes and/or modifications may be made to the present disclosure, as illustrated in specific embodiments. Accordingly, the present embodiments are to be considered in all respects as illustrative and not limiting.

Claim 1. A subscriber unit adapted to perform scheduling of uplink radio resources thereon, wherein the at least one unlicensed cell is configured to communicate between the subscriber unit and a radio base station that is responsible for scheduling uplink radio resources in the unlicensed cell, the subscriber device contains:

a receiving device that operatively receives from a radio base station a first stage uplink resource scheduling message indicating uplink radio resources that can be used by a subscriber unit to perform uplink transmissions through an unlicensed cell,

wherein the receiving device in operation receives from the radio base station a second stage uplink resource scheduling message, which is associated with a first stage uplink resource scheduling message,

a processor that, in operation, determines whether the first stage uplink resource scheduling message is valid,

wherein the processor operatively determines upon receiving a second stage uplink resource scheduling message that an uplink transmission is scheduled if the processor determines that the first stage uplink resource scheduling message is valid,

wherein the determination of whether a first stage uplink resource scheduling message is valid is based on determining whether an uplink transmission was initiated by another second stage uplink resource scheduling message within a predetermined period of time prior to receipt of said message second stage uplink resource scheduling, and

a transmitting device that, in operation and when determined by the processor that an uplink transmission is scheduled, performs an uplink transmission through an unlicensed cell.

Statement 2. The subscriber equipment according to Statement 1, in which the processor operatively determines that the first stage uplink resource scheduling message is valid when the uplink transmission has not been initiated by another second stage uplink resource scheduling message in a predetermined time. a period of time before receiving said second stage uplink resource scheduling message.

Statement 3. A subscriber equipment according to Statement 1, wherein the processor operatively invalidates a first stage uplink resource scheduling message when initiating an uplink transmission via another second stage uplink resource scheduling message within a predetermined period of time before receiving said message. second stage uplink resource scheduling,

wherein the processor operatively determines that the first stage uplink resource scheduling message is valid when the first stage uplink resource scheduling message is not determined to be invalid.

Provision 4. A subscriber equipment according to one of Provisions 1 to 3, wherein a first stage uplink resource scheduling message is addressed to the subscriber device, and a second stage uplink resource scheduling message is generally addressed to a plurality of subscriber equipments receiving the scheduling message second stage uplink resources,

wherein, optionally, the first stage uplink resource scheduling message is addressed to the subscriber equipment by the subscriber device-specific identification used in transmitting the first stage uplink resource scheduling message, and wherein the subscriber device-specific identification are configurable; And

wherein, optionally, the second stage uplink resource scheduling message is generally addressed to a plurality of user equipments receiving the second stage uplink resource scheduling message by a shared identity used in transmitting the uplink resource scheduling message the second stage, wherein the shared identification data is predefined and is common to a plurality of subscriber devices.

Provision 5. A subscriber equipment according to one of Provisions 1 to 4, wherein the first stage uplink resource scheduling message indicates a predetermined period of time during which the first stage uplink resource scheduling message can be considered in conjunction with the received uplink resource scheduling message second stage connections,

wherein, optionally, the processor determines that the first stage uplink resource scheduling message is considered in conjunction with the second stage uplink resource scheduling message if the second stage uplink resource scheduling message is received within a specified predetermined time period after receiving the first stage uplink resource scheduling message.

Provision 6. A subscriber equipment according to one of Provisions 1 to 5, wherein the first stage uplink resource scheduling message further indicates a first time offset to be taken into account when performing an uplink transmission, and wherein the second stage uplink resource scheduling message stage indicates a second time offset that must be taken into account when performing uplink transmission,

wherein, optionally, the transmitting device operatively performs uplink transmission at least after the sum of the first and second time offsets upon receipt of the second stage uplink resource scheduling message.

Provision 7. A subscriber equipment according to one of Provisions 1 to 6, wherein the first stage uplink resource scheduling message is a downlink control information (DCI) message of format 0A, 0B, 4A or 4B, respectively, containing a first stage flag indicating that the DCI message is a first uplink resource scheduling message corresponding to two-stage uplink resource scheduling,

wherein optionally, the second stage uplink resource scheduling message is a 1C format downlink control information (DCI) message containing a second stage flag indicating that the DCI message is a second uplink resource scheduling message , corresponding to two-stage uplink resource scheduling.

Claim 8. A method for operating a subscriber unit to perform uplink radio resource scheduling thereon, wherein the at least one unlicensed cell is configured to communicate between the subscriber unit and a radio base station that is responsible for scheduling uplink radio resources for the unlicensed cell, the method comprises the steps of:

receiving from the radio base station a first stage uplink resource scheduling message indicating uplink radio resources that can be used by the subscriber equipment to perform uplink transmission through the unlicensed cell,

receiving from the radio base station a second stage uplink resource scheduling message that is associated with a first stage uplink resource scheduling message,

determining whether the first stage uplink resource scheduling message is valid,

determining, upon receiving the second stage uplink resource scheduling message, that an uplink transmission is scheduled in case it is determined that the first stage uplink resource scheduling message is valid,

wherein the determination of whether a first stage uplink resource scheduling message is valid is based on determining whether an uplink transmission was initiated by another second stage uplink resource scheduling message within a predetermined period of time prior to receipt of said message second stage uplink resource scheduling, and

perform uplink transmission through an unlicensed cell in case it is determined that uplink transmission is scheduled.

Claim 9. The method of Clause 8, further comprising determining that the first stage uplink resource scheduling message is valid when the uplink transmission has not been initiated by another second stage uplink resource scheduling message in a predetermined time. a period of time before receiving said second stage uplink resource scheduling message.

Provision 10. The method according to Provision 8, further comprising the steps of:

invalidate the first stage uplink resource scheduling message when initiating uplink transmission by another second stage uplink resource scheduling message in a predetermined period of time before receiving said second stage uplink resource scheduling message, and

determining that the first stage uplink resource scheduling message is valid when the first stage uplink resource scheduling message is not determined to be invalid.

Clause 11. A method according to one of Clauses 8 to 10, wherein a first stage uplink resource scheduling message is addressed to a user equipment, and a second stage uplink resource scheduling message is generally addressed to a plurality of subscriber equipments receiving the resource scheduling message. second stage uplink,

wherein, optionally, the first stage uplink resource scheduling message is addressed to the subscriber equipment by the subscriber device-specific identification used in transmitting the first stage uplink resource scheduling message, and wherein the subscriber device-specific identification are configurable; And

wherein, optionally, the second stage uplink resource scheduling message is generally addressed to a plurality of user equipments receiving the second stage uplink resource scheduling message by means of shared identities used in transmitting the second stage uplink resource scheduling message stage, wherein the shared identification data is predefined and is common to a plurality of subscriber devices.

Clause 12. A method according to one of Clauses 8 to 11, wherein the first stage uplink resource scheduling message specifies a predetermined period of time during which the first stage uplink resource scheduling message may be considered together with the received uplink resource scheduling message. second stage,

wherein the method optionally further comprises determining that the first stage uplink resource scheduling message is considered in conjunction with the second stage uplink resource scheduling message in case the second stage uplink resource scheduling message is received at for a specified predetermined period of time after receiving the first stage uplink resource scheduling message.

Clause 13. The method according to one of Clauses 8 to 12, wherein the first stage uplink resource scheduling message further indicates a first time offset to be taken into account when performing an uplink transmission, and wherein the second stage uplink resource scheduling message indicates a second time offset that must be taken into account when performing uplink transmission,

wherein the method optionally further comprises performing an uplink transmission after at least the sum of the first and second time offsets upon receiving the second stage uplink resource scheduling message.

Clause 14. A method according to one of Clauses 8 to 13, wherein the first stage uplink resource scheduling message is a downlink control information (DCI) message of format 0A, 0B, 4A or 4B, respectively, containing a first stage flag, indicating that the DCI message is a first uplink resource scheduling message corresponding to two-stage uplink resource scheduling,

wherein optionally, the second stage uplink resource scheduling message is a 1C format downlink control information (DCI) message containing a second stage flag indicating that the DCI message is a second uplink resource scheduling message , corresponding to two-stage uplink resource scheduling.

Claims (39)

1. An integrated circuit that, when in operation, controls a process of a subscriber unit to perform scheduling with respect to uplink radio resources, wherein at least one unlicensed cell is configured to communicate between the subscriber unit and a radio base station to schedule uplink radio resources for the unlicensed cell. cells, and the process contains: receiving from the radio base station a first stage uplink resource scheduling message indicating uplink radio resources that can be used by the subscriber unit to perform uplink transmission through the unlicensed cell, receiving from the radio base station a second stage uplink resource scheduling message that is associated with a first stage uplink resource scheduling message, determining whether the first stage uplink resource scheduling message is valid, determining, upon receiving the second stage uplink resource scheduling message, that uplink transmission is scheduled in case it is determined that the first stage uplink resource scheduling message is valid, wherein the determination of whether a first stage uplink resource scheduling message is valid is based on determining whether an uplink transmission was initiated by another second stage uplink resource scheduling message within a predetermined period of time prior to receipt of said message second stage uplink resource scheduling, and performing an uplink transmission through an unlicensed cell when it is determined that an uplink transmission is scheduled. 2. The integrated circuit of claim 1, wherein the process further comprises determining that the first stage uplink resource scheduling message is valid when the uplink transmission has not been previously initiated by another second stage uplink resource scheduling message. a certain period of time before receiving said second stage uplink resource scheduling message. 3. Integrated circuit according to claim 1, wherein the process additionally contains: invalidating a first stage uplink resource scheduling message when initiating an uplink transmission by another second stage uplink resource scheduling message in a predetermined period of time before receiving said second stage uplink resource scheduling message, and determining that the first stage uplink resource scheduling message is valid when the first stage uplink resource scheduling message is not determined to be invalid. 4. Integrated circuit according to one of claims 1-3, wherein the first stage uplink resource scheduling message is addressed to the user equipment, and the second stage uplink resource scheduling message is generally addressed to a plurality of user equipments receiving the second stage uplink resource scheduling message; and/or the first stage uplink resource scheduling message is addressed to the subscriber equipment by the subscriber equipment-specific identification used in transmitting the first stage uplink resource scheduling message, and wherein the subscriber equipment-specific identification is configurable; and/or The second stage uplink resource scheduling message is generally addressed to a plurality of user equipments receiving the second stage uplink resource scheduling message by shared identities used in transmitting the second stage uplink resource scheduling message, wherein the shared identities the data is predefined and common to multiple subscriber devices. 5. Integrated circuit according to one of claims 1-4, wherein the first stage uplink resource scheduling message indicates a predetermined period of time during which the first stage uplink resource scheduling message can be considered together with the received second stage uplink resource scheduling message; and/or the process further comprises determining that the first stage uplink resource scheduling message is considered in conjunction with the second stage uplink resource scheduling message in the event that the second stage uplink resource scheduling message is received within a specified predetermined period of time after receiving the scheduling message first stage uplink resources. 6. Integrated circuit according to one of claims 1-5, wherein the first stage uplink resource scheduling message further indicates a first time offset that should be taken into account when performing an uplink transmission, and wherein the second stage uplink resource scheduling message indicates a second time offset that should be taken into account when performing an uplink transmission communications; and/or the process further comprises performing an uplink transmission at least after the sum of the first and second time offsets upon receiving the second stage uplink resource scheduling message. 7. Integrated circuit according to one of claims 1-6, wherein The first stage uplink resource scheduling message is a downlink control information (DCI) message of format 0A, 0B, 4A, or 4B, respectively, containing a first stage flag indicating that the DCI message is a first uplink resource scheduling message. communications corresponding to two-stage uplink resource scheduling; and/or The second stage uplink resource scheduling message is a 1C format downlink control information (DCI) message containing a second stage flag indicating that the DCI message is a second uplink resource scheduling message corresponding to uplink resource scheduling with two stages. 8. A radio base station for uplink resource scheduling, wherein the at least one unlicensed cell is configured to communicate between a subscriber unit and a radio base station for uplink radio resource scheduling in the unlicensed cell, wherein the radio base station comprises: a transmitting device that operatively transmits to the user equipment a first stage uplink resource scheduling message indicating uplink radio resources that can be used by the user equipment to perform uplink transmissions through an unlicensed cell, wherein the transmitting device, in operation, transmits to the subscriber device a second stage uplink resource scheduling message, which is associated with the first stage uplink resource scheduling message, wherein the determination of whether a first stage uplink resource scheduling message is valid is based on determining whether an uplink transmission was initiated by another second stage uplink resource scheduling message within a predetermined period of time prior to receipt of said message scheduling second stage uplink resources at the subscriber equipment, and a receiving device that, in operation, receives uplink communications through an unlicensed cell. 9. A method implemented in a radio base station for scheduling uplink radio resources, wherein the at least one unlicensed cell is configured to communicate between a subscriber unit and the radio base station for scheduling uplink radio resources in the unlicensed cell, the method comprising the steps of: where: transmitting to the subscriber equipment a first stage uplink resource scheduling message indicating uplink radio resources that can be used by the subscriber equipment to perform uplink transmission through the unlicensed cell, transmitting to the user equipment a second stage uplink resource scheduling message that is associated with the first stage uplink resource scheduling message, wherein the determination of whether a first stage uplink resource scheduling message is valid is based on determining whether an uplink transmission was initiated by another second stage uplink resource scheduling message within a predetermined period of time prior to receipt of said message scheduling second stage uplink resources at the subscriber equipment, and perform uplink reception through an unlicensed cell. 10. An integrated circuit that, in operation, controls a process of a radio base station to schedule uplink resources with respect to it, wherein the at least one unlicensed cell is configured to communicate between a subscriber unit and the radio base station to schedule uplink radio resources in the unlicensed saute, and the process contains: transmitting to the subscriber equipment a first stage uplink resource scheduling message indicating uplink radio resources that can be used by the subscriber equipment to perform uplink transmission through the unlicensed cell, transmitting to the user equipment a second stage uplink resource scheduling message that is associated with the first stage uplink resource scheduling message, wherein the determination of whether a first stage uplink resource scheduling message is valid is based on determining whether an uplink transmission was initiated by another second stage uplink resource scheduling message within a predetermined period of time prior to receipt of said message scheduling second stage uplink resources at the subscriber equipment, and performing uplink reception through an unlicensed cell.