Improved two-phase triggering process

Abstract

An improved two-phase triggering process is described. An integrated circuit configured to operate a user equipment includes: a receiving circuit that receives from a radio base station: a first-phase uplink resource scheduling message indicating uplink radio resources available for the user equipment to perform uplink transmissions via an unlicensed cell, and a second-phase uplink resource scheduling message relating to the first-phase uplink resource scheduling message; a control circuit coupled to the receiving circuit that determines the first-phase uplink resource scheduling message is valid in response to a defined time period prior to the reception of the second-phase uplink resource scheduling message during which uplink transmissions have not been triggered by another second-phase uplink resource scheduling message; and a transmitting circuit coupled to the control circuit that performs uplink transmissions via an unlicensed cell in response to the first-phase uplink resource scheduling message being determined to be valid.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on November 2, 2017, with application number 201780066684.7, entitled "Improved Two-Phase Triggering Process", and filed by Panasonic Corporation (USA). Technical Field

[0002] This disclosure relates to user equipment for scheduling using uplink radio resources and methods for operating user equipment. Background Technology

[0003] Long Term Evolution (LTE)

[0004] Third-generation mobile systems (3G) based on WCDMA radio access technology are being deployed extensively around the world. The first step in enhancing or evolving this technology requires the introduction of High-Speed ​​Downlink Packet Access (HSDPA) and enhanced uplink (also known as High-Speed ​​Uplink Packet Access (HSUPA)) to provide a highly competitive radio access technology.

[0005] To prepare for increasingly demanding user needs and to remain competitive with new radio access technologies, 3GPP introduced a new mobile communication system called Long Term Evolution (LTE). LTE is designed to meet the carrier requirements for high-speed data and media transmission and high-capacity voice support for the next decade.

[0006] The Long Term Evolution (LTE) Work Item (WI) specifications (known as Evolved UMTS Terrestrial Radio Access (UTRA) and Evolved UMTS Terrestrial Radio Access Network (UTRAN)) have been finalized as Version 8 (LTE Rel. 8). The LTE system represents a highly efficient packet-based radio access and radio access network that provides full IP functionality with low latency and low cost. In LTE, several scalable transmission bandwidths, such as 1.4, 3.0, 5.0, 10.0, 15.0, and 20.0 MHz, are specified to allow for flexible system deployment using a given spectrum. In the downlink, Orthogonal Frequency Division Multiplexing (OFDM)-based radio access is employed due to its inherent immunity to multipath interference (MPI), which is achieved through low symbol rates, the use of cyclic prefixes (CP), and their association with different transmission bandwidth arrangements. In the uplink, Single Carrier Frequency Division Multiple Access (SC-FDMA)-based radio access is employed because, given the limited transmit power of User Equipment (UE), providing wide-area coverage takes precedence over increasing peak data rates. It employs many key packet radio access technologies, including multiple-input multiple-output (MIMO) channel transmission technology, and implements an efficient control signaling structure in LTE Release 8 / 9.

[0007] LTE architecture

[0008] Figure 1 The overall architecture is illustrated. E-UTRAN includes eNodeBs, which provide E-UTRA user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination to User Equipment (UE). The eNodeB (eNB) hosts the Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Control Protocol (PDCP) layers, which include user plane header compression and encryption functionality. The eNodeB also provides Radio Resource Control (RRC) functionality corresponding to the control plane. The eNodeB performs numerous functions, including radio resource management, permission control, scheduling, imposing negotiated uplink Quality of Service (QoS), cell information broadcasting, encryption / decryption of user and control plane data, and compression / decompression of downlink / uplink user plane packet headers. eNodeBs are interconnected via X2 interfaces.

[0009] The eNodeB also connects to the EPC (Evolved Packet Core) via the S1 interface, more specifically, to the MME via the S1-MME (Mobility Management Entity) and to the Serving Gateway (SGW) via S1-U. The S1 interface supports many-to-many relationships between the MME / Serving Gateway and the eNodeB. The SGW routes and forwards user data packets, and also functions as a mobility anchor for the user plane during handover between eNodeBs, and as a mobility anchor for LTE and other 3GPP technologies (terminating the S4 interface and relaying services between 2G / 3G systems and the PDN GW). For idle user equipment, the SGW terminates the downlink data path and triggers paging when downlink data arrives for the user equipment. The SGW manages and stores user equipment context, such as parameters of IP bearer services or intra-network routing information. In the event of lawful interception, the SGW also performs replication of user services.

[0010] The MME is a key control node for LTE access networks. The MME is responsible for idle-mode UE tracking and paging processes, including retransmission. The MME participates in bearer activation / disabling processes and is also responsible for selecting the SGW for UEs during initial attachment and during intra-LTE handover involving core network (CN) node relocation. The MME is responsible for authenticating users (through interaction with the HSS). Non-access stratum (NAS) signaling terminates at the MME, and the MME is also responsible for generating and assigning temporary identifiers to UEs. The MME checks the authorization for UEs to camp on the service provider's Public Land Mobile Network (PLMN) and imposes UE roaming restrictions. The MME is the endpoint in the network for encryption / integrity protection of NAS signaling and handles security key management. The MME also supports lawful interception of signaling. The MME also provides control plane functions for mobility between LTE and 2G / 3G access networks using the S3 interface terminated from the SGSN. The MME also terminates the S6a interface toward the home HSS for roaming UEs.

[0011] Component carrier structure in LTE

[0012] Within a so-called subframe, the downlink component carriers of the 3GPP LTE system are subdivided in the time-frequency domain. In 3GPP LTE, each subframe is divided as follows: Figure 2 The diagram shows two downlink time slots, where the first downlink time slot includes a control channel area (PDCCH area) within the first OFDM symbol. Each subframe includes a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Release 8), where each OFDM symbol spans the entire bandwidth of the component carrier. Therefore, each OFDM symbol comprises multiple modulation symbols transmitted on the corresponding subcarrier. In LTE, the signal transmitted in each time slot is... Subcarriers and Resource grid description of OFDM symbols. This refers to the number of resource blocks within the bandwidth. It depends on the downlink transmission bandwidth configured in the cell, and should meet the following requirements. in and These are the minimum and maximum downlink bandwidths supported by the current version of the specification. This refers to the number of subcarriers in a resource block. For a normal cyclic prefix subframe structure, and

[0013] In a multi-carrier communication system, such as one employing OFDM (e.g., as used in 3GPP Long Term Evolution (LTE)), the smallest resource unit that can be allocated by the scheduling unit is a "resource block". A physical resource block (PRB) is defined as consecutive OFDM symbols (e.g., 7 OFDM symbols) in the time domain and consecutive subcarriers in the frequency domain, such as... Figure 2 As shown (e.g., 12 subcarriers for component carriers). In 3GPP LTE (Release 8), the physical resource block is therefore composed of resource elements, corresponding to a time slot in the time domain and 180 kHz in the frequency domain (for further details on the downlink resource grid, see, for example, 3GPP TS36.211, “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 incorporated herein by reference).

[0014] A subframe comprises two time slots, resulting in 14 OFDM symbols in the subframe when using the so-called "normal" CP (Cyclic Prefix) and 12 OFDM symbols when using the so-called "extended" CP. For terminology purposes, time-frequency resources equal to the same consecutive subcarriers spanning the entire subframe are referred to below as "resource block pairs" or equivalent "RB pairs" or "PRB pairs." The term "component carrier" refers to 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 term "cell" will be used, referring to a combination of downlink and optional uplink resources. The system information transmitted on downlink resources indicates the association between the carrier frequencies of the downlink resources and the carrier frequencies of the uplink resources.

[0015] Similar assumptions about the component carrier structure also apply to later versions.

[0016] Carrier aggregation in LTE-A to support wider bandwidth

[0017] The spectrum for Advanced IMT was determined at the World Radiocommunication Conference (WRC-07) in 2007. While the overall spectrum for IMT-Advanced was determined, the actual available frequency bandwidth varied by region or country. However, following the decision on the overview of available spectrum, the standardization of radio interfaces began within the 3rd Generation Partnership Project (3GPP).

[0018] Advanced LTE systems can support a bandwidth of 100MHz, while LTE systems only support 20MHz. Currently, the lack of radio spectrum has become a bottleneck for the development of wireless networks, making it difficult to find a sufficiently wide spectrum band for advanced LTE systems. Therefore, there is an urgent need to find ways to obtain a wider radio spectrum band, and one possible answer is carrier aggregation.

[0019] In carrier aggregation, two or more component carriers are aggregated to support a wider transmission bandwidth of up to 100MHz. Several cells in an LTE system are aggregated into a wider channel in an Advanced LTE system, wide enough to reach 100MHz, even if these cells in LTE may be in different frequency bands. All component carriers can be configured to be Rel.8 / 9 compatible, at least as long as the bandwidth of the component carriers does not exceed the bandwidth supported by the LTE Rel.8 / 9 cell. Not all component carriers aggregated by a user equipment (UE) need to be Rel.8 / 9 compatible. Existing mechanisms (such as blocking) can be used to prevent Rel-8 / 9 UEs from camping on component carriers.

[0020] User equipment can receive or transmit simultaneously on one or more component carriers (corresponding to multiple serving cells) depending on its capabilities. Assuming the component carrier structure follows the Rel.8 / 9 specification, an LTE-A Rel.10 user equipment with receive and / or transmit capabilities for carrier aggregation can receive and / or transmit simultaneously on multiple serving cells, while an LTE-A Rel.8 / 9 user equipment can only receive and transmit on a single serving cell.

[0021] Carrier aggregation is supported for both continuous and non-continuous component carriers, with each component carrier limited to a maximum of 110 resource blocks in the frequency domain (using 3GPP LTE (Revision 8 / 9) digitization).

[0022] User equipment (UEs) compliant with 3GPP LTE-A (Release 10) can be configured to aggregate varying numbers of component carriers originating from the same eNodeB (base station), as well as potentially different bandwidths in the uplink and downlink. The number of configurable downlink component carriers depends on the UE's downlink aggregation capability. Conversely, the number of configurable uplink component carriers depends on the UE's uplink aggregation capability. Currently, it is not possible to configure a mobile terminal with more uplink component carriers than downlink component carriers. In a typical TDD deployment, the number of component carriers in both the uplink and downlink, and the bandwidth of each component carrier, are the same. Component carriers originating from the same eNodeB do not need to provide the same coverage.

[0023] The spacing between the center frequencies of consecutive aggregated component carriers should be a multiple of 300kHz. This is to ensure compatibility with the 100kHz frequency grating of 3GPP LTE (Revision 8 / 9) while maintaining the orthogonality of subcarriers with a 15kHz spacing. Depending on the aggregation scenario, an n×300kHz spacing can be achieved by inserting a small number of unused subcarriers between consecutive component carriers.

[0024] The aggregation of multiple carriers is only exposed upwards to the MAC layer. For both uplink and downlink, a HARQ entity is required in the MAC for each aggregated component carrier. (In the absence of SU-MIMO for the uplink) There is at most one transport block per component carrier. The transport block and its potential HARQ retransmissions need to be mapped onto the same component carrier.

[0025] When carrier aggregation is configured, the mobile terminal has only one RRC connection with the network. During RRC connection establishment / re-establishment, a cell provides security inputs (one ECGI, one PCI, and one ARFCN) and non-access stratum mobility information (e.g., TAI), similar to LTE Rel.8 / 9. After RRC connection establishment / re-establishment, the component carriers corresponding to that cell are called the downlink primary cell (PCell). In connected state, each UE always configures one and only one downlink PCell (DL PCell) and one uplink PCell (UL PCell). In the configured set of component carriers, the other cells are called secondary cells (SCells); the carriers of an SCell are the downlink secondary component carriers (DL SCC) and the uplink secondary component carriers (UL SCC). Currently, a maximum of five serving cells, including PCells, can be configured for a UE.

[0026] The RRC can perform the configuration, reconfiguration, addition, and removal of component carriers. For example, the empirical MAC control unit can activate and deactivate them. During intra-LTE handover, the RRC can 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 the SCell's system information, which is necessary for transmission / reception (similar to handover in Rel-8 / 9). When an SCell is added to a UE, each SCell is configured with a serving cell index; PCells always have serving cell index 0.

[0027] When a user equipment (UE) is configured with carrier aggregation, there is at least one pair of always-active uplink and downlink component carriers. This pair of downlink component carriers can also be referred to as "DL anchor carriers." The same applies to the uplink. When carrier aggregation is configured, UEs can be scheduled on multiple component carriers simultaneously, but at most one random access procedure should be in progress at any given 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 into the corresponding DCI (Downlink Control Information) format.

[0028] The association established between uplink and downlink component carriers via RRC signaling allows for the identification of uplink component carriers that are authorized to apply when there is no cross-carrier scheduling. The association between downlink and uplink component carriers is not necessarily one-to-one. In other words, more than one downlink component carrier can be associated with the same uplink component carrier. Conversely, a downlink component carrier can be associated with only one uplink component carrier.

[0029] Uplink / Downlink Scheduling

[0030] The MAC function in eNodeB refers to scheduling, through which the eNB allocates available radio resources within a cell among UEs and in each UE's radio bearers. In principle, the eNodeB allocates downlink and uplink resources to each UE based on downlink data cached in the eNodeB and Buffer Status Reports (BSRs) received from the UE, respectively. During this process, the eNodeB considers the QoS requirements of each configured radio bearer and selects the size of the MAC PDU.

[0031] The typical scheduling mode is dynamic scheduling using downlink grant / allocation messages (DCIs) for allocating downlink transmission resources and uplink grant / allocation messages for allocating uplink transmission resources. These are transmitted on the Physical Downlink Control Channel (PDCCH) using a Cell Radio Network Temporary Identifier (C-RNTI) to identify the UE's intent. In addition to dynamic scheduling, persistent scheduling is defined, which allows radio resources to be semi-statically configured and allocated to UEs over a period longer than one subframe, thus avoiding the need for specific downlink allocation messages or uplink grant messages on the PDCCH for each subframe. For persistent scheduling configuration or reconfiguration, RRC signaling indicates the resource allocation interval for periodically allocating radio resources. When the PDCCH is used to configure or reconfigure persistent scheduling, the scheduling messages applied to persistent scheduling need to be distinguished from those used for dynamic scheduling. For this purpose, special scheduling identifiers are used, called semi-persistent scheduling C-RNTIs, SPS-C-RNTIs, which differ for each UE from the C-RNTI used for dynamic scheduling messages.

[0032] To inform scheduled users of their assignment status, transmission format, and other transmission-related information (e.g., HARQ information, Transmission Power Control (TPC) commands), L1 / L2 control signaling is transmitted along with data on the downlink. Assuming user assignment can change with each subframe, L1 / L2 control signaling is multiplexed with downlink data within the subframe. It should be noted that user assignment can also be performed on a TTI (Transmission Time Interval) basis, where the TTI length can be a multiple of the subframe length. The TTI length can be fixed for all users in the service area, can be different for different users, or can even be dynamic for each user. Typically, L1 / 2 control signaling only needs to be sent once per TTI. Without loss of generality, the following assumption is made that the TTI equals one subframe.

[0033] L1 / L2 control signaling is transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH carries messages as Downlink Control Information (DCI), which in most cases includes resource allocation and other control information for mobile terminals or UE groups. Typically, several PDCCHs can be transmitted in a single subframe.

[0034] Downlink control information occurs in several formats, which differ in overall size and the information contained in their fields. The different DCI formats currently defined for LTE 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 incorporated herein by reference). For more information on DCI formats and the specific information transmitted in the DCI, see the aforementioned technical standards or LTE – The UMTS Long Term Evolution – From Theory to Practice (edited by Stefanie Sesia, Issam Toufik, and Matthew Baker), Chapter 9.3, incorporated herein by reference. Other formats may be defined in the future.

[0035] Layer 1 / Layer 2 (L1 / L2) control signaling

[0036] To inform scheduled users of their assignment status, transmission format, and other transmission-related information (e.g., HARQ information, transmit power control (TPC) commands), L1 / L2 control signaling is transmitted along with data on the downlink. Assuming user assignment can change with each subframe, L1 / L2 control signaling is multiplexed with downlink data within the subframe. It should be noted that user assignment can also be performed based on the TTI (Transmission Time Interval), where the TTI length can be a multiple of the subframe length. The TTI length can be fixed for all users in the service area, can vary for different users, or can even be dynamic for each user. Generally, only one L1 / L2 control signaling transmission is required per TTI. Without loss of generality, it is assumed below that the TTI is equivalent to one subframe.

[0037] L1 / L2 control signaling is transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH carries messages as Downlink Control Information (DCI), which in most cases includes resource allocation and other control information for mobile terminals or UE groups. Typically, several PDCCHs can be transmitted in a subframe.

[0038] It should be noted that in 3GPP LTE, the allocation of uplink data transmission (also known as uplink scheduling permission or uplink resource allocation) is also transmitted on the PDCCH. Furthermore, 3GPP Release 11 introduced the EPDCCH, which performs essentially the same function as the PDCCH, namely, transmitting L1 / L2 control signaling, even though the detailed transmission method differs from the PDCCH. Further details can be found in the current versions of 3GPP TS 36.211 and 36.213, which are incorporated herein by reference. Therefore, unless specifically indicated, most of the items outlined in the background techniques and embodiments apply to the PDCCH as well as the EPDCCH or other means of transmitting L1 / L2 control signals.

[0039] Typically, information transmitted on L1 / L2 control signaling for allocating uplink or downlink radio resources (especially in LTE(-A) version 10) can be divided into the following items:

[0040] - User identifier, indicating the assigned user. It is typically included in the checksum by masking the CRC with the user identifier;

[0041] - Resource allocation information, indicating the resources (e.g., resource blocks (RBs)) allocated to the user. Alternatively, this information is called Resource Block Allocation (RBA). Note that the number of RBs allocated to the user can be dynamic;

[0042] - Carrier indicator, which is used when the control channel allocation transmitted on the first carrier involves the resources of the second carrier (i.e., the resources on the second carrier or the resources related to the second carrier);

[0043] (Cross-carrier scheduling);

[0044] - Modulation and coding methods, determining the modulation method and coding rate to be used;

[0045] - HARQ information, such as New Data Indicator (NDI) and / or Redundant Version (RV), is particularly useful in the retransmission of data packets or portions thereof;

[0046] - Power control command, which adjusts the transmission power of the allocated uplink data or control information transmission;

[0047] - Reference signal information, such as the cyclic shift and / or orthogonal cover code index used, which is used for the transmission or reception of reference signals in relation to allocation;

[0048] - An uplink or downlink allocation index is used to identify the allocation order, which is particularly useful in TDD systems;

[0049] - Frequency hopping information, such as indications of whether and how resource frequency hopping is applied to increase frequency diversity;

[0050] - A CSI request is used to trigger the transmission of channel state information in the allocated resources; and

[0051] - Multi-cluster information is a flag used to indicate and control whether transmission occurs in a single cluster (a set of neighboring RBs) or multiple clusters (at least two non-nearby sets of neighboring RBs). Multi-cluster assignment has been introduced by 3GPP LTE-(A) Release 10.

[0052] Note that the list above is non-exhaustive and depends on the DCI format used; not all of the information items must be present in every PDCCH transmission.

[0053] Downlink control information appears in several formats, which differ in overall size and the information contained in their fields. Some DCI formats currently defined for LTE are listed below. More detailed information is provided in 3GPP technical standard TS 36.212v14.0.0 (especially in section 5.3.3.1, “DCI formats,” which is incorporated herein by reference).

[0054] - Format 0: DCI Format 0 is used to transmit resource grants for PUSCH using single-antenna port transmission in uplink transmission mode 1 or 2.

[0055] - Format 1: DCI Format 1 is used for transmitting resource allocation for single codeword PDSCH transmission (downlink transmission modes 1, 2 and 7).

[0056] - Format 1A: DCI Format 1A is a compact signaling used for resource allocation of single codeword PDSCH transmissions and for assigning dedicated pre-signatures to mobile terminals for contention-free random access (for all transmission modes).

[0057] - Format 1B: DCI Format 1B is a compact signaling (downlink transmission mode 6) used for resource allocation of PDSCH transmissions using closed-loop precoding for rank-1 transmissions. The information sent is the same as in Format 1A, but an indicator of the precoding vector applied to the PDSCH transmission is added.

[0058] - Format 1C: Format 1C is used for very compact transmission of PDSCH allocation. When using Format 1C, PDSCH transmission is limited to QPSK modulation. This is used, for example, for signaling paging messages and broadcast system information messages.

[0059] - Format 1D: DCI Format 1D is a compact signaling used for resource allocation in PDSCH transmissions using multi-user MIMO. The information transmitted is the same as in Format 1B; however, instead of one of the bits of the precoding vector indicator, a single bit is present to indicate whether a power offset is applied to the data symbol. This feature is needed to indicate whether transmission power is shared between two UEs. Future versions of LTE may extend this to cases where power is shared between a larger number of UEs.

[0060] - Format 2: DCI Format 2 is used for transmitting resource allocation of PDSCH for closed-loop MIMO operation (transmission mode 4).

[0061] - Format 2A: DCI Format 2A is used to transmit resource allocation for PDSCH in open-loop MIMO operation. The transmitted information is the same as Format 2, except that if the eNodeB has two transmit antenna ports, there is no precoded information, and for four antenna ports, two bits are used to indicate the transmission rank (transmission mode 3).

[0062] - Format 2B: Introduced in version 9 and used for transmitting resource allocation for PDSCH with dual beamforming (transmission mode 9).

[0063] - Format 2C: Introduced in version 10 and used for transmitting resource allocation of PDSCH for closed-loop single-user or multi-user MIMO operations with up to 8 layers (transmission mode 9).

[0064] - Format 2D: Introduced in version 11 and used for transports up to 8 layers; primarily used for COMP (Cooperative Multipoint) (transport mode 10).

[0065] - Formats 3 and 3A: DCI formats 3 and 3A are used to transmit power control commands for PUCCH and PUSCH, with 2 bits or 1 bit of power regulation respectively. These DCI formats contain separate power control commands for UE groups.

[0066] - Format 4: DCI Format 4 is used for scheduling PUSCH in closed-loop spatial multiplexing transmission in uplink transmission mode 2.

[0067] - Format 5: DCI Format 5 is used for scheduling PSCCH (Physical Side Link Control Channel) and also contains several SCI Format 0 fields for scheduling PSSCH (Physical Side Link Shared Control Channel). If the number of information bits in DCI Format 5 mapped to a given search space is less than the payload size of Format 0 used for scheduling the same serving cell, zeros should be appended to Format 5 until the payload size is equal to the size of Format 0 including any padding bits appended to Format 0.

[0068] LTE-Licensed Assisted Access (LAA) on unlicensed frequency bands

[0069] In September 2014, 3GPP launched a new research project on LTE operation in unlicensed spectrum. The reason for extending LTE to unlicensed bands is the growing demand for wireless broadband data and the limited number of licensed bands. Therefore, cellular operators are increasingly viewing unlicensed spectrum as a complementary tool to enhance their service offerings. One advantage of LTE in unlicensed bands compared to relying on other radio access technologies (RATs) such as Wi-Fi is that supplementing the LTE platform with unlicensed spectrum access allows operators and vendors to leverage existing or planned LTE / EPC hardware investments in radio and core networks.

[0070] However, it must be considered that, due to the inevitable coexistence with other Radio Access Technologies (RATs) (such as Wi-Fi) in unlicensed spectrum, the quality of unlicensed spectrum access cannot match that of licensed spectrum access. Therefore, at least initially, LTE operation on unlicensed bands will be considered as a complement to LTE on licensed spectrum, rather than as an independent operation on unlicensed spectrum. Based on this assumption, 3GPP established the term Licensed Assisted Access (LAA) for LTE operation on unlicensed bands in conjunction with at least one licensed band. However, future independent operation of LTE on unlicensed spectrum, i.e., without the assistance of licensed cells, should not be excluded. Enhanced Licensed Assisted Access (eLAA) is an enhancement to LAA, particularly utilizing unlicensed spectrum in the uplink. Effectively utilizing unlicensed spectrum as a complement to licensed spectrum has the potential to bring significant value to service providers and ultimately to the entire wireless industry. To fully realize the benefits of LTE operation in unlicensed spectrum, defining a complete UL access scheme in addition to the already defined DL access scheme is crucial.

[0071] The general LAA approach currently intended by 3GPP is to utilize the already specified Rel-12 Carrier Aggregation (CA) framework as much as possible. This CA framework configuration, as described above, includes a so-called primary cell (PCell) carrier and one or more secondary cell (SCell) carriers. CA typically supports cell-based self-scheduling (scheduling information and user data are transmitted on the same component carrier) and inter-cell cross-carrier scheduling (scheduling information regarding the PDCCH / EPDCCH and user data regarding the PDSCH / PUSCH are transmitted on different component carriers).

[0072] Figure 4The diagram illustrates a very basic scenario with a licensed PCell, namely licensed SCell 1, and various unlicensed SCells 2, 3, and 4 (exemplarily described as small cells). The transmitting / receiving network nodes of unlicensed SCells 2, 3, and 4 can be remote radio heads managed by the eNB, or they can be nodes attached to the network but not managed by the eNB. For simplicity, the connections of these nodes to the eNB or network are not explicitly shown in the diagram.

[0073] Currently, the basic approach envisioned in 3GPP is that PCells will operate on licensed frequency bands, while one or more SCells will operate on unlicensed frequency bands. One advantage of this strategy is that PCells can be used to control the reliable transmission of messages and user data with high Quality of Service (QoS) requirements, such as voice and video, while, depending on the scenario, SCells on unlicensed spectrum may experience some degree of QoS degradation due to the inevitable coexistence with other RATs.

[0074] It has been agreed that the LAA will focus on the unlicensed 5 GHz band. Therefore, one of the most critical issues is coexistence with Wi-Fi (IEEE 802.11) systems operating on these unlicensed bands. To support fair coexistence between LTE and other technologies such as Wi-Fi, and to ensure fairness among different LTE operators within the same unlicensed band, channel access for LTE on unlicensed bands must comply with a set of regulatory rules, which may depend in part on the geographic region and the specific band. A comprehensive description of the regulatory requirements for all regions operating on the unlicensed 5 GHz band is given in R1-144348, “Regulatory Requirements for Unlicensed Spectrum” (Alcatel-Lucent et al., RAN1#78bis, September 2014, incorporated herein by reference) and 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 a LAA include Dynamic Frequency Selection (DFS), Transmit Power Control (TPC), Listen-After-Talk (LBT), and discontinuous transmissions with finite maximum transmission duration. 3GPP aims for a single global framework for LAAs, which essentially means that system designs must take into account all the requirements of different regions and frequency bands within the 5GHz band.

[0075] For example, in Europe, certain limitations are set for rated channel bandwidth, as is evident from Section 4.3 of the current version 1.8.1 of European standard ETSI EN301 893, which is incorporated herein by reference. Rated channel bandwidth is the widest frequency band allocated to a single channel, including guard bands. Occupied channel bandwidth is the bandwidth containing 99% of the signal power. Allows the device to operate simultaneously in one or more adjacent or non-adjacent channels.

[0076] The Listen-Before-Speak (LBT) process is defined as a mechanism in which equipment applies a Clear Channel Assessment (CCA) check before using a channel. CCA utilizes at least energy detection to determine the presence of other signals on the channel, thus identifying whether the channel is occupied or cleared. Regulations in Europe and Japan currently mandate the use of LBT in unlicensed spectrum. Beyond regulatory requirements, carrier sensing via LBT is a way to fairly share unlicensed spectrum and is therefore considered an important feature of fair and amicable operation of unlicensed spectrum within a single global solution framework.

[0077] In unlicensed spectrum, channel availability cannot always be guaranteed. Furthermore, certain regions, such as Europe and Japan, prohibit continuous transmission and impose limits on the maximum duration of transmission bursts in unlicensed spectrum. Therefore, discontinuous transmission with a finite maximum transmission duration is a required feature of LAA (Laser Alignment). Certain regions and frequency bands require DFS (Distributed Spectrum Detection) to detect interference from radar systems and avoid co-channel operation with these systems. Additionally, the goal is to achieve near-uniform spectrum loading. DFS operation and its corresponding requirements are associated with the master-slave principle. The master device should detect radar interference, but can rely on another device associated with the master device to achieve radar detection.

[0078] Compared to operation on licensed bands, operation on the unlicensed 5 GHz band is limited to considerably lower transmit power levels in most areas, resulting in small coverage areas. Even when licensed and unlicensed carriers are transmitted at the same power, unlicensed carriers in the 5 GHz band are generally expected to support smaller coverage areas than licensed cells in the 2 GHz band due to increased path loss and shadowing effects on the signal. A further requirement for certain areas and bands is the use of TPC (Transmission Control Program) to reduce the average interference level induced by other equipment operating on the same unlicensed band.

[0079] Detailed information can be found in the harmonized European standard ETSI EN 301 893 (current version 1.8.1), which is incorporated herein by reference.

[0080] Following European regulations on LBT, devices must perform a Clear Channel Assessment (CCA) before occupying a radio channel with data transmission. Transmission on an unlicensed channel is only permitted after the channel has been detected as idle based on, for example, energy detection. Specifically, the device must observe the channel for a minimum period during the CCA (e.g., 20 μs for Europe, see ETSI 301 893, section 4.8.3). If the detected energy level exceeds a configured CCA threshold (e.g., -73 dBm / MHz for Europe, see ETSI 301 893, section 4.8.3), the channel is considered occupied; conversely, if the detected power level is below the configured CCA threshold, the channel is considered idle. If the channel is determined to be occupied, transmission should not be performed on that channel during the next fixed frame period. If the channel is classified as idle, the device is permitted to transmit immediately. Maximum transmission duration is limited to ensure fair resource sharing with other devices operating in the same frequency band.

[0081] CCA energy detection is performed over the entire channel bandwidth (e.g., 20 MHz in an unlicensed 5 GHz band), meaning that the received power level of all subcarriers of the LTE OFDM symbol within the channel contributes to the energy level assessed by the device performing CCA.

[0082] In addition to the CCA described above, if the device is classified as a load-based device (LBE) according to the description in ETSI 301 893 section 4.9.2.2 (incorporated hereby by reference), an additional extended CCA (ECCA) may be required. ECCA includes an additional CCA observation time multiplied by a random factor N by the duration of the CCA observation slot. N defines the number of cleared idle slots that result in a total idle period that must be observed before initiating a transmission.

[0083] Furthermore, the total time a device transmits on a given carrier without reassessing the carrier's availability (i.e., LBT / CCA) is defined as the channel occupancy time (see ETSI 301 893, section 4.8.3.1). The channel occupancy time should be in the range of 1 ms to 10 ms, where the maximum channel occupancy time could be, for example, 4 ms as currently defined for Europe. Additionally, there exists a minimum idle time during which the UE is not permitted to transmit after transmission on an unlicensed cell, said minimum idle time being at least 5% of the channel occupancy time. At the end of the idle period, the UE can perform a new CCA, etc. This transmission behavior in Figure 5 The figure is schematically shown in the diagram, which is taken from ETSI EN 301 893 (its... Figure 2 : "Example of timing for Frame BasedEquipment").

[0084] Figure 6 This illustrates the timing between Wi-Fi transmissions and LAA UE transmissions on a specific frequency band (unlicensed cell). (See from...) Figure 5 As can be seen, after a Wi-Fi burst, at least a CCA gap is required before the eNB "reserves" the unlicensed cell until the next subframe boundary, for example, by sending a reservation signal. Then, the actual LAA DL burst begins. This will similarly apply to the LTE UE, which, after successfully performing a CCA, will reserve a subframe by sending a reservation signal so that the actual LAA UL burst can then begin.

[0085] Uplink scheduling in unlicensed cells

[0086] Provide DCI formats 0A, 0B, 4A, and 4B for eLAA to support single-subframe and multi-subframe licensing as well as uplink transmission (PUSCH) for single and multiple antenna ports respectively.

[0087] • DCI format 0A: Single subframe, single antenna port

[0088] • DCI format 0B: Multi-subframe, single antenna port

[0089] • DCI Format 4A: Single subframe, multiple antenna ports

[0090] • DCI Format 4B: Multi-subframe, multi-antenna port

[0091] Details about these DCI formats can be found in 3GPP technical standard TS 36.212v14.0.0 (parts 5.3.3.1.1A, 5.3.3.1.1B, 5.3.3.1.8A, and 5.3.3.1.8B), which are incorporated herein by reference.

[0092] Any of these DCI formats (i.e., uplink grants) can be a single-phase grant or part of a two-phase grant. In the current exemplary implementation in LTE (see TS 36.212), this is reflected in the “PUSCH Trigger A” field, a 1-bit field that distinguishes whether the received uplink grant is used for “non-triggered scheduling” (when the bit value is 0 (i.e., single-phase uplink grant)) or for “triggered scheduling” (when the bit value is 1 (i.e., two-phase uplink grant)). This can be controlled by the eNB, the responsible radio network entity that schedules radio resources to the UE.

[0093] The two-phase uplink scheduling process requires the UE to receive two separate messages (“Trigger A” and “Trigger B”) in a specific manner in order to schedule an uplink transmission.

[0094] The trigger message A can be any of the aforementioned uplink grants (i.e., DCI formats 0A, 0B, 4A, or 4B). Related to this two-phase grant, the four DCI formats include the following data fields, as currently defined in technical standard TS 36.212v14.0.0:

[0095] “PUSCH triggers A-1 bits, where a value of 0 indicates non-triggering scheduling and a value of 1 indicates triggering scheduling, as defined in Section 8.0 of [3].

[0096] - Timing offset – 4 bits as defined in [3].

[0097] - When the flag for triggered scheduling is set to 0,

[0098] - This field indicates the absolute timing offset of the PUSCH transmission.

[0099] -In addition to this,

[0100] - The first two bits of this field indicate the relative timing offset of the PUSCH transmission.

[0101] - The last two bits of this field indicate the valid time window for PUSCH scheduling via triggered scheduling.

[0102] Additionally, the available DCI formats for triggering A messages include common data fields indicating radio resources scheduled for uplink transmission, such as the "Resource Block Allocation" field, the "Modulation and Coding Method" field, and the "HARQ Process Number" field. Furthermore, DCI formats 0A, 0B, 4A, and 4B (especially DCI CRC) can be scrambled with UE-specific identifiers (such as C-RNTI) to address the corresponding uplink grant to a specific UE.

[0103] The trigger B message has DCI format 1C, as currently defined in section 5.3.3.1.4 of TS 36.212v14.0.0, which is incorporated herein by reference. DCI format 1C, as currently defined in the technical standard for use within the scope of unlicensed carrier transmissions, includes a two-stage licensing process as follows:

[0104] "other

[0105] -LAA subframe configuration – as defined in Section 13A of [3] 4 bits

[0106] -Uplink transmission duration and offset indication - 5 bits as defined in Section 13A of [3]. This field is only applicable to UEs configured with uplink transmission on LAA SCells.

[0107] -PUSCH trigger B - as defined in Section 8.0 of [3], 5 bits. This field is only applicable to UEs configured with uplink transmission on the LAA SCell.

[0108] - Add reserved information bits until the size is equal to the size of Format 1C used for very compact scheduling of a PDSCH codeword.

[0109] When used as part of a two-phase authorization process as described above, the trigger B message (DCI format 1C) is typically not addressed to a specific UE, but rather a shared identifier (in this case, CC-RNTI; Common Control RNTI, which is the RNTI used in the context of providing Common Control PDCCH information; see 3GPP TS 36.321 v14.0.0, which is incorporated herein by reference) can be used by the eNB to scramble DCI format 1C, particularly its CRC.

[0110] The cross-reference “[3]” in the above reference of TS 36.212 refers to the technical standard 3GPP TS 36.213, current version 14.0.0, in which at least sections 8.0 and 13 relate to two-phase licensing, and therefore its entire contents are incorporated herein by reference.

[0111] Specifically, Section 8 of TS 36.213 defines in detail when and how LAA SCell performs uplink transmissions (i.e., PUSCH):

[0112] "For a serving cell as an LAA SCell, the UE should..."

[0113] - When a PDCCH / EPDCCH with DCI format 0A / 0B / 4A / 4B is detected in subframe n intended for use by the UE and the 'PUSCH Trigger A' field is set to '0', or

[0114] - When a PDCCH / EPDCCH with DCI format 0A / 0B / 4A / 4B is detected in the most recent subframe nv, which is intended for use by the UE, and the 'PUSCH trigger A' field is set to '1', and a PDCCH with DCI CRC scrambled by CC-RNTI is detected in subframe n, and the 'PUSCH trigger B' field is set to '1'.

[0115] Based on PDCCH / EPDCCH and HARQ process ID mod(n) HARQ_ID +i,N HARQ In subframe n+1+k+i (where i = 0, 1, ..., N-1), the corresponding PUSCH transmission is performed according to the channel access procedure described in Section 15.2.1, where...

[0116] - For DCI format 0A / 4A, N=1, and the value of N is determined by the "Number of scheduled subframes" field in the corresponding DCI format 0B / 4B.

[0117] - The UE is configured with the maximum value of N through the higher-level parameter maxNumberOfSchedSubframes-Format0B of DCI format 0B and the higher-level parameter maxNumberOfSchedSubframes-Format4B of DCI format 4B;

[0118] - If the 'PUSCH Trigger A' field is set to '0' or Table 8.2e, then the value of k is determined by the scheduling delay field in the corresponding DCI0A / 0B / 4A / 4B according to Table 8.2d; otherwise;

[0119] -n HARQ_ID The value is determined by the HARQ process number field in the corresponding DCI format 0A / 0B / 4A / 4B, and N HARQ =16;

[0120] - For the 'PUSCH trigger A' field that is set to '0' in the corresponding DCI format 0A / 0B / 4A / 4B

[0121] -l=4

[0122] -otherwise

[0123] The value of -l is the UL offset determined by the 'UL configuration for LAA' field in the corresponding DCI, where the CRC is scrambled by CC-RNTI according to the procedure in subsection 13A, and the 'PUSCH trigger B' field is set to '1'.

[0124] The value of -v is determined by the verification 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 is set to '1'.

[0125] The minimum value of l+k supported by the UE is included in UE-EUTRA-Capability.

[0126] Table 8.2d: For k in DCI format 0A / 0B / 4A / 4B, the 'PUSCH trigger A' field is set to '0'.

[0127]

[0128]

[0129] Table 8.2e: For k in DCI format 0A / 0B / 4A / 4B, the 'PUSCH trigger A' field is set to '1'.

[0130] The value of the 'scheduling delay' field k 00 0 01 1 10 2 11 3

[0131] Table 8.2f: For v in DCI format 0A / 0B / 4A / 4B, the 'PUSCH trigger A' field is set to '1'.

[0132]

[0133] Therefore, current 3GPP technical standards define in great detail how to perform the two-phase licensing process. However, it should be noted that the currently standardized definition of the two-phase licensing process provided above is subject to continuous change and improvement, and therefore may change in the future. Therefore, the implementation of the two-phase licensing process according to the current 3GPP technical standards described above is considered merely an implementation example, and many details are not essential to this invention.

[0134] However, for this invention, it is assumed that the basic concepts behind the two-stage licensing process will remain the same as those discussed above. Specifically, it will be combined with Figure 7 Explain the basic concepts. Figure 7 The functionality of a two-phase authorization process, including the sending and receiving of DCI messages including Trigger A and Trigger B, is illustrated. For the following exemplary discussion, it is assumed that the illustrated subframes are numbered by using the subframe in which Trigger B (i.e., the second-phase uplink scheduling message) is received in the UE as reference subframe n; preceding and following subframes are numbered accordingly. Further, it is assumed that Trigger A is received at subframe n-3, and a time window of length v is defined within which the two-phase authorization process can be effectively performed. In other words, the time window can be viewed as defining a period of time within which Trigger B can be received in order to actually trigger the corresponding uplink transmission based on the transmission parameters indicated by Trigger A and / or Trigger B messages.

[0135] The time window length v can be indicated, for example, within the trigger A message, as in the last 2 bits of the timing offset field of DCI format 0A, 0B, 4A, 4B in TS 36.212 and Table 8.2.f of TS 36.213, as illustrated above.

[0136] When a trigger B message is received at subframe n, the UE determines whether it received a related trigger A message within a time window of length v (starting immediately before the receipt of the trigger B message, i.e., the range from n-1 to nv). In the illustrated scenario, a trigger A scheduling message is received in subframe n-3 and therefore within the time window, triggering uplink transmission in the UE. Then, uplink transmission (i.e., PUSCH) is performed at subframe n+offset with a specific transmission timing offset. The UE can perform uplink transmission, for example, using indicated radio resources and modulation and coding schemes, based on the information received in the trigger A and trigger B messages.

[0137] Precise PUSCH timing offset is less critical to this invention. Exemplarily, as currently standardized in TS36.213, the PUSCH timing offset is “l+k+i”, where parameter l is defined by the trigger B message (see the “Uplink Transmission Duration and Offset Indication” field of DCI format 1C in TS 36.212 and Tables 13A-2 in TS 36.213), and parameter k is defined by the trigger a message (see the first two bits of the “Timing Offset” field of any of DCI formats 0A, 0B, 4A, and 4B in TS 36.212, and Table 8.2e in TS 36.213). Parameter i applies to cases where multiple uplink subframes are scheduled via a two-stage uplink scheduling process, and in that case, the number of licensed subframes run from 0 is reduced by 1 (otherwise it is simply 0). Further details can be derived from Section 8 of TS 36.213 referenced above. However, the PUSCH timing offset used to perform uplink transmissions according to the two-stage uplink scheduling process can also be defined differently or even be predetermined.

[0138] As mentioned above, 3GPP has defined a two-phase scheduling process for uplink transmissions in unlicensed cells. However, this two-phase scheduling process can be further improved. Summary of the Invention

[0139] Non-limiting and exemplary embodiments provide improved methods and user equipment relating to scheduling uplink transmissions performed by user equipment.

[0140] The independent claims provide for non-limiting and exemplary embodiments. Advantageous embodiments are limited by the dependent claims.

[0141] According to one general aspect, a user equipment (UE) for scheduling uplink radio resources is described. At least one unlicensed cell is configured to communicate between the UE and a radio base station responsible for scheduling uplink radio resources on the unlicensed cell. The UE includes: a receiving unit that receives from the radio base station a first-phase uplink resource scheduling message indicating uplink radio resources that the UE can use to perform uplink transmissions via the unlicensed cell. The receiving unit receives from the radio base station a second-phase uplink resource scheduling message related to the first-phase uplink resource scheduling message. The UE further includes a processing unit that determines whether the first-phase uplink resource scheduling message is valid. Upon receiving the second-phase uplink resource scheduling message, the processing unit determines to schedule uplink transmissions if it has already determined that the first-phase uplink resource scheduling message is valid. Thus, determining whether the first-phase uplink resource scheduling message is valid is based on whether an uplink transmission has been triggered by another second-phase uplink resource scheduling message within a predetermined time period prior to the reception of the second-phase uplink resource scheduling message. The user equipment also includes a transmitting unit that performs uplink transmissions via an unlicensed cell, provided that the processing unit has determined the scheduling of the uplink transmission. The cell may be, for example, an unlicensed cell in the context of 3GPP LTE Release 14, or another cell that supports two-phase scheduling.

[0142] Accordingly, in another general aspect, the technology disclosed herein is characterized by a method for operating a user equipment (UE) that utilizes uplink radio resources for scheduling. At least one unlicensed cell is configured to communicate between the UE and a radio base station responsible for scheduling uplink radio resources on the unlicensed cell. The method includes: receiving a first-phase uplink resource scheduling message from the radio base station, indicating that the UE can use uplink radio resources to perform uplink transmissions via the unlicensed cell. The method further includes receiving a second-phase uplink resource scheduling message from the radio base station in relation to the first-phase uplink resource scheduling message. The method further includes determining whether the first-phase uplink resource scheduling message is valid. The method further includes, upon receiving the second-phase uplink resource scheduling message, determining to schedule uplink transmissions if the first-phase uplink resource scheduling message has been determined to be valid. Thus, determining whether the first-phase uplink resource scheduling message is valid is based on whether an uplink transmission has been triggered by another second-phase uplink resource scheduling message within a predetermined time period prior to the reception of the second-phase uplink resource scheduling message. The method also includes performing uplink transmission via an unlicensed cell when the uplink transmission schedule has been determined.

[0143] Accordingly, in another general aspect, the technology disclosed herein is characterized by an integrated circuit configured to operate a user equipment, the integrated circuit comprising: a receiving circuit that receives from a radio base station: a first-stage uplink resource scheduling message indicating uplink radio resources available for the user equipment to perform uplink transmissions via an unlicensed cell, and a second-stage uplink resource scheduling message relating to the first-stage uplink resource scheduling message; a control circuit coupled to the receiving circuit that determines the first-stage uplink resource scheduling message is valid in response to the uplink transmission not being triggered by another second-stage uplink resource scheduling message within a defined time period prior to the reception of the second-stage uplink resource scheduling message; and a transmitting circuit coupled to the control circuit that performs the uplink transmission via the unlicensed cell in response to the first-stage uplink resource scheduling message being determined to be valid.

[0144] Accordingly, in another general aspect, the technology disclosed herein is characterized by a radio base station for scheduling uplink radio resources, wherein at least one unlicensed cell is configured for communication between a user equipment and the radio base station for scheduling uplink radio resources on the unlicensed cell, wherein the radio base station comprises: a transmitting unit that transmits a first-stage uplink resource scheduling message to the user equipment, the first-stage uplink resource scheduling message indicating that the user equipment can use uplink radio resources for performing uplink transmissions via the unlicensed cell; the transmitting unit that transmits a second-stage uplink resource scheduling message to the user equipment in relation to the first-stage uplink resource scheduling message, wherein the determination of whether the first-stage uplink resource scheduling message is valid is based on a determination of whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to the reception of the second-stage uplink resource scheduling message at the user equipment; and a receiving unit that performs uplink reception via the unlicensed cell.

[0145] Accordingly, in another general aspect, the technology disclosed herein is characterized by a method implemented in a radio base station for scheduling uplink radio resources, wherein at least one unlicensed cell is configured for communication between a user equipment and a radio base station for scheduling uplink radio resources on the unlicensed cell, wherein the method includes: sending a first-stage uplink resource scheduling message to the user equipment, the first-stage uplink resource scheduling message indicating uplink radio resources available for the user equipment to perform uplink transmissions via the unlicensed cell; sending a second-stage uplink resource scheduling message related to the first-stage uplink resource scheduling message to the user equipment, wherein the determination of whether the first-stage uplink resource scheduling message is valid is based on a determination of whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to the reception of the second-stage uplink resource scheduling message at the user equipment; and performing uplink reception via the unlicensed cell.

[0146] Accordingly, in another general aspect, the technology disclosed herein is characterized by an integrated circuit for controlling a process of scheduling uplink radio resources, wherein at least one unlicensed cell is configured for communication between a user equipment and a radio base station for scheduling uplink radio resources on the unlicensed cell, wherein the process includes: sending a first-stage uplink resource scheduling message to the user equipment, the first-stage uplink resource scheduling message indicating uplink radio resources available for the user equipment to perform uplink transmissions via the unlicensed cell; sending a second-stage uplink resource scheduling message related to the first-stage uplink resource scheduling message to the user equipment, wherein the determination of whether the first-stage uplink resource scheduling message is valid is based on a determination of whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to the reception of the second-stage uplink resource scheduling message at the user equipment; and performing uplink reception via the unlicensed cell.

[0147] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and accompanying drawings. Advantages and / or benefits may be provided individually by the various embodiments and features disclosed in the specification and accompanying drawings, and need not all be provided to obtain one or more of them.

[0148] These general and specific aspects can be achieved using user devices and methods, as well as combinations of user devices and methods. Attached Figure Description

[0149] In the following description, exemplary embodiments are described in more detail with reference to the accompanying drawings.

[0150] Figure 1 An exemplary architecture of a 3GPP LTE system is shown.

[0151] Figure 2 An exemplary downlink resource grid for a subframe's downlink slots as defined for 3GPP LTE (Revision 8 / 9) is shown.

[0152] Figure 3 An exemplary uplink resource grid for uplink slots in a subframe defined for 3GPP LTE is shown.

[0153] Figure 4 An exemplary LAA scenario with several licensed and unlicensed cells is shown.

[0154] Figure 5 The transmission behavior of LAA transmission is shown.

[0155] Figure 6 The timing between Wi-Fi transmissions for unlicensed cells and downlink bursts for LAA UEs is shown.

[0156] Figure 7 An exemplary illustration shows a two-phase uplink scheduling process provided for uplink transmission via an unlicensed cell.

[0157] Figure 8 This illustrates multiple triggers of uplink transmission in a multi-UE environment.

[0158] Figure 9 This illustrates a first implementation according to an embodiment to prevent multiple triggering of uplink transmissions in a multi-UE environment.

[0159] Figure 10 This is a diagram illustrating the two-stage uplink transmission process according to the first implementation of this embodiment.

[0160] Figure 11 The second implementation according to this embodiment is shown to prevent multiple triggering of uplink transmissions in a multi-UE environment, and

[0161] Figure 12 This is a diagram of the two-stage uplink transmission process according to the second implementation of this embodiment.

[0162] Specific implementation method

[0163] A mobile station, mobile node, user terminal, or user equipment is a physical entity within a communication network. A node can have several functional entities. A functional entity is a software or hardware module that implements and / or provides a predetermined set of functions to other functional entities within the node or network. A node can have one or more interfaces that attach the node to a communication facility or medium on which the node can communicate. Similarly, a network entity can have logical interfaces that attach functional entities to a communication facility or medium through which it can communicate with other functional entities or communication nodes.

[0164] The term “radio resources” as used in the claims and applications should be interpreted broadly to refer to physical radio resources, such as time and frequency resources.

[0165] The terms “unlicensed cell” or “unlicensed carrier” as used in the claims and this application should be broadly interpreted as a cell / carrier operating in an unlicensed frequency band with a specific frequency bandwidth. Correspondingly, the terms “licensed cell” or “licensed carrier” as used in the claims and this application should be broadly interpreted as a cell / carrier operating in a licensed frequency band with a specific frequency bandwidth. Exemplarily, these terms will be understood in the context of 3GPP Release 12 / 13 and the Licensed Assisted Access Work Item.

[0166] Figure 8 The diagram shows UEs belonging to UE group #1, UEs belonging to UE group #2, and eNodeB.

[0167] Suppose that Trigger A, as a Phase 1 uplink resource scheduling message, is sent from eNodeB to UE in group #1 at subframe n-2. In this exemplary case, the effective time window of Trigger A sent to UE in group #1 is 5 subframes. Therefore, information about the effective time window is provided by Trigger A itself.

[0168] Further assume that trigger B is sent from the eNodeB as a Phase 2 uplink resource scheduling message at subframe n. Trigger B is received by two UEs in groups #1 and #2. Although the eNodeB has sent trigger B, its intention is to send the same Phase 2 uplink resource scheduling message (as in the Phase 1 uplink resource scheduling message) for the UE in group #1 at subframe n-2 as for the previously sent trigger A. In this exemplary case, assume that the UE in group #2 did not receive any trigger A within the corresponding valid time window prior to trigger B. Upon receiving trigger B, all UEs capable of receiving trigger B (which typically includes UEs from both group #1 and group #2) need to check whether they received trigger A within the corresponding valid time window. Therefore, in this example, the UE in group #1 checks whether it received trigger A up to 5 subframes prior (in this case, from subframe n-5 to subframe n-1). Since trigger A has already been received in subframe n-2 within the valid time window, the UE in group #1 will subsequently trigger uplink transmission.

[0169] Since the UE in group #2 has not yet received trigger A, trigger B received in subframe n will not trigger uplink transmission for the UE in group #2.

[0170] As from Figure 8 It is further evident that the UE of group #2 receives trigger A at subframe n+1. In this exemplary case, the effective time window for trigger A sent to the UE of group #2 is 3 subframes. As further shown in the figure, a second trigger B is sent from the eNodeB (at subframe n+3). The second trigger B is again received by both UEs of groups #1 and #2, although the eNodeB has sent the second trigger B with the intent that it is the same second-stage uplink resource scheduling message for trigger A (as in the first-stage uplink resource scheduling message) sent to the UE of group #2 at subframe n+1. Upon receiving trigger B, the UE of group #2 checks whether it has already received trigger A up to 3 subframes prior (in this case, from subframe n to subframe n+2). Since the corresponding trigger A has already been received in subframe n+1, which is within the effective time window, the UE of group #2 will subsequently trigger uplink transmission.

[0171] However, since the second trigger B is also received at subframe n+3 at the UE of group #1, the UE of group #1 will again check whether it has received trigger A up to 5 subframes earlier (in this case, from subframe n-2 to subframe n+2). Considering that the UE of group #1 has already received trigger A at subframe n-2 (i.e., still within the valid time window of the received trigger A), the UE of group #1 will again trigger its second uplink transmission, although the eNodeB does not intend for the second triggered uplink transmission to be performed by the UE of group #1, but only by the UE of group #2. According to... Figure 8 In the exemplary scenario shown, if the second trigger B is received at subframe n+2 (instead of at subframe n+3), this second-trigger uplink transmission performed by the UE of group #1 will also occur. However, if the second trigger B is received at or after subframe n+4, then considering the exemplary effective time window of 5 subframes for the UE of group #1, multiple triggers of the uplink transmission will not occur.

[0172] In general, multiple triggers of such uplink transmissions are undesirable in multi-UE environments. The first reason is the risk of interfering with other transmissions in the corresponding subframes. The second reason is that such multiple triggers can lead to UL transmission conflicts: if a UE in group #1 is triggered by trigger B in subframe n, where the corresponding UL transmission is indicated by trigger A to last for 4 subframes, the corresponding UL transmission exemplarily occurs in subframes n+2 to n+5. If the same UE in group #1 is again triggered by trigger B in subframe n+3, then the corresponding UL transmission indicated by the same trigger A should again last for 4 subframes, and the corresponding UL transmission exemplarily occurs in subframes n+5 to n+8. It can be seen that these two triggers will therefore result in a conflict in subframe n+5, where it is unclear whether the data is sent as a result of the first trigger B or the second trigger B – even if the transmission resources are the same in both cases, the corresponding data typically contains different transport blocks or packets. This conflict should be avoided as it can lead to misunderstandings between the UE and the eNodeB.

[0173] The inventors have conceived of the following exemplary embodiments to mitigate one or more of the above-mentioned problems.

[0174] Specific implementations of various embodiments will be implemented within the broad specifications given in the 3GPP standard and are described in part in the Background section, with the addition of specific key features as illustrated below with respect to the various implementations of the presented embodiments. It should be noted that this embodiment can be advantageously used, for example, in mobile communication systems, such as the 3GPP LTE-A (versions 10 / 11 / 12 / 13 and later) communication systems described in the Background section above, but the embodiment is not limited to its use in these specific exemplary communication networks.

[0175] The description should not be construed as limiting the scope of this disclosure, but is merely an example of embodiments for a better understanding of the disclosure. Those skilled in the art will recognize that the general principles of the disclosure, as broadly outlined in the claims and in the description given in the summary section of the specification, can be applied to different scenarios and in ways not explicitly described below. Several assumptions are made for purposes of illustration and explanation, but these assumptions should not unduly limit the scope of the following embodiments.

[0176] Furthermore, as described above, the following embodiments can be implemented in a 3GPP LTE-A (Rel. 12 / 13 and later) environment. The various embodiments primarily allow for improved uplink transmission schemes. However, other functions (i.e., functions unchanged in the various embodiments) can remain exactly the same as those described in the Background section, or can be changed without affecting the various embodiments. For example, defining how the functions and procedures (e.g., segmentation, modulation, coding, beamforming, multiplexing) and scheduling (PDCCH, DCI, cross-carrier scheduling, self-scheduling) of uplink transmission are actually performed, or how normal uplink transmission timing (e.g., initial timing advance, timing advance update command) is performed using timing advance procedures.

[0177] The following describes general embodiments for addressing the above-described problems in detail, which will be illustrated using the following exemplary scenarios designed to readily illustrate the principles of the embodiments. However, these principles can also be applied to other scenarios, some of which will be explicitly mentioned below.

[0178] The UE initiates a two-phase uplink resource scheduling. Specifically, resource scheduling is initiated by a Phase 1 uplink resource scheduling message (trigger A) for unlicensed cells, which is received by the UE's receiving unit. Subsequently, the UE's receiving unit receives a Phase 2 uplink resource scheduling message (trigger B) for unlicensed cells.

[0179] Subsequently, the UE's processing unit determines whether the first-stage uplink resource scheduling message (trigger A) is valid during the first-stage uplink resource scheduling message verification. Therefore, the determination of the validity of the first-stage uplink resource scheduling message (trigger A) is based on the determination of whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message (trigger B) within a predefined time period prior to the reception of the second-stage uplink resource scheduling message (trigger B).

[0180] Subsequently, when the second-stage uplink resource scheduling message (trigger B) is received, and the processing unit has already determined that the first-stage uplink resource scheduling message (trigger A) is valid, the processing unit determines to schedule uplink transmission.

[0181] Finally, if the processing unit determines that uplink transmission has been scheduled, the UE's transmitting unit performs uplink transmission via an unlicensed cell.

[0182] As described above, this main principle of the invention advantageously allows for the prevention of multiple uplink transmissions in a multi-UE environment. Since there is no risk that a trigger B intended for a different UE may unintentionally trigger a second uplink transmission for a specific UE that has already previously triggered an uplink transmission within the effective time window, the eNodeB can send a new trigger A to a different UE immediately after sending trigger B, even within a predetermined time period / effective time window.

[0183] In this way, user / cell throughput can be significantly improved. Furthermore, avoiding multiple uplink transmission triggers reduces the required trigger A overhead, as the longer validity period indicated by trigger A can be used more efficiently.

[0184] Furthermore, a false alarm of a second trigger B following a correct first trigger B within the valid time / valid time window will not lead to an incorrect PUSCH transmission. This advantageously avoids errors caused by false alarm trigger B.

[0185] Figure 9 A first implementation of this embodiment is shown, in which multiple triggering of uplink transmissions in a multi-UE environment is prevented.

[0186] Figure 9 The above combination is basically shown. Figure 8 The situation regarding trigger reception at UEs in groups #1 and #2 has already been described. As discussed, the UE in group #1 receives trigger B at subframe n+3. To avoid a second trigger in the uplink transmission (which would be combined with...) Figure 8 In the conventional system described above, the UE of group #1 checks whether another trigger B has already triggered uplink transmission within a predetermined time period prior to the reception of trigger B received in subframe n+3. Preferably, the predetermined time period is the valid time window indicated in the trigger A message. In this example, the predetermined time period is a valid time window of 5 subframes in length (as combined with...). Figure 8 As already explained, trigger A notifies the UE of the number of subframes in the effective time window (v=5).

[0187] Therefore, the UE in group #1 checks whether another trigger B has already triggered uplink transmission within the time period of 5 subframes prior to subframe n+3. Specifically, the UE in group #1 checks whether another trigger B has already triggered uplink transmission between subframes n-2 and n+2. Figure 8As shown, the uplink transmission has already been triggered by trigger B received in subframe n. Therefore, to avoid multiple triggers of the uplink transmission within the effective time window of trigger A, for any trigger B received after the first trigger B (received in subframe n in this example), the UE ignores trigger A received in subframe n-2, which will create an effective time window between subframes n-2 and n+2, and will allow trigger B received in subframe n+3 to trigger another uplink transmission. Specifically, ignoring trigger A received in subframe n-2 and then avoiding trigger B received in subframe n+3 will trigger the uplink transmission because no effective time window will be found before trigger B is received in subframe n+3. It should be noted that in the case of a previous uplink transmission triggered within the effective time window of this trigger A, the expression "ignore trigger A" means that trigger A received in subframe n-2 is "not considered" for trigger B received in subframe n+3.

[0188] As a result, and as Figure 9 As shown, the UE in group #1 did not trigger the unwanted second / multiple uplink transmissions at subframe n+3. Therefore, in this case, only the UE in group #2 triggers the uplink transmission at subframe n+3 via the received trigger B. This solution avoids / prevents multiple triggers in a multi-UE environment.

[0189] Figure 10 Based on the above combination Figure 9 A diagram illustrating the two-stage uplink transmission process of the first implementation of the previously mentioned embodiments.

[0190] In step S101, the UE (either of UEs in group #1 and #2) initiates a two-phase uplink resource scheduling. Specifically, the resource scheduling is initiated by a first-phase uplink resource scheduling message for unlicensed cells, which is received by the UE in step S102. Subsequently, in step S103, the UE receives a second-phase uplink resource scheduling message for unlicensed cells.

[0191] The first-stage uplink resource scheduling message verification includes step S104, which determines whether the uplink transmission was triggered by another second-stage uplink resource scheduling message during a time period T prior to the reception of the second-stage uplink resource scheduling message. Therefore, "time period T" corresponds to the "predetermined time period prior to the reception of the second-stage uplink resource scheduling message" as reflected in the claims, and corresponds to... Figure 8 and 9 The "effective time window" is shown.

[0192] If it has been determined that another uplink transmission has been performed within time period T ("Yes" in step S104), the process proceeds to step S102, waiting for the next cycle of the first-stage uplink resource scheduling message.

[0193] However, if it is determined in step S104 that no other uplink transmissions were performed within time period T ("No" in step S104), the process proceeds to step S105, which involves determining that the first-stage uplink resource scheduling message is valid.

[0194] When the first-stage uplink resource scheduling message is valid, the process proceeds to step S106, which involves scheduling uplink transmission. Subsequently, in step S107, the uplink transmission is actually executed.

[0195] Figure 11 A second implementation of this embodiment is shown, in which multiple triggerings of uplink transmissions in a multi-UE environment are prevented. The second implementation is an alternative to the first implementation; however, multiple triggerings of uplink transmissions for the same UE within the effective time window of trigger A are avoided by invalidating trigger A instead of simply ignoring trigger A as described in the first implementation.

[0196] refer to Figure 9 In the scenario where the second trigger B has already been received by the UE of group #1 at subframe n+3. As an alternative to the first implementation of this embodiment, based on... Figure 11 In the second implementation of the embodiment, the UE of group #1 can actively invalidate trigger A (which has already been received at subframe n-2) when trigger B is received in subframe n (or it can be invalidated in subframe n+1 or n+2, but this needs to be done before interpreting / analyzing / considering the second trigger B at subframe n+3). Therefore, the second trigger B received at subframe n+3 cannot trigger uplink transmission at the UE of group #1 because there is no longer a valid time window for trigger A. In other words, the second implementation of this embodiment actively disables / invalidates trigger A when the first trigger B that has already triggered uplink transmission is received (or at least before receiving the next trigger B). Therefore, by actively disabling / invalidating trigger A, thereby removing the valid time window for trigger A, the UE of group #1 will not trigger multiple unintended uplink transmissions.

[0197] In summary, it should be noted that the second implementation of the embodiment (according to) Figure 11 This is typically different from the first implementation (according to...). Figure 9 and 10The key difference lies in the fact that, when uplink transmission has already been triggered by trigger B, trigger A is invalidated (the valid time window of trigger A is removed), rather than simply ignoring trigger A (ignoring the valid time window of trigger A) upon receiving a second trigger B. Figure 9 As shown.

[0198] For example, an active “invalidate / disable trigger A” can be achieved by switching a specific bit in the field associated with the invalidation / disabling of the Phase 1 uplink transmission resource scheduling message trigger A.

[0199] Figure 12 Based on the above combination Figure 11 A diagram illustrating the two-stage uplink transmission process of the second implementation of the previously mentioned embodiments.

[0200] In step S101, the UE (either of UEs in group #1 and #2) initiates a two-phase uplink resource scheduling. Specifically, the resource scheduling is initiated by a first-phase uplink resource scheduling message for unlicensed cells, which is received by the UE in step S102. Subsequently, in step S103, the UE receives a second-phase uplink resource scheduling message for unlicensed cells.

[0201] The first-stage uplink resource scheduling message verification includes step S108, which determines whether the first-stage uplink resource scheduling message has been invalidated. If it is determined that the first-stage uplink resource scheduling message has been invalidated ("Yes" in step S108), the process proceeds to step S102, waiting for the next cycle of the first-stage uplink resource scheduling message, or proceeds to step S103, waiting for the second-stage uplink resource scheduling message.

[0202] If it is determined in step S108 that the first-stage uplink resource scheduling message was not invalidated (No in step S108), the process proceeds to step S105, which involves determining that the first-stage uplink resource scheduling message is valid. Subsequently, when the first-stage uplink resource scheduling message is valid, the process proceeds to step S106, which involves scheduling uplink transmission. Then, in step S107, the uplink transmission is actually executed. Afterward, the process proceeds to step S109, which involves invalidating the first-stage uplink resource scheduling message. Then, the process proceeds to step S102, waiting for the next cycle of the first-stage uplink resource scheduling message, or proceeds to step S103, waiting for the second-stage uplink resource scheduling message.

[0203] For example, if a second-stage uplink resource scheduling message is received after the first-stage uplink resource scheduling message has become invalid (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, causing the process to proceed again to step S102 or step S103 without performing uplink transmission.

[0204] The process described above reflects, as Figure 11 The specific behavior shown is that the second trigger B at subframe n+3 does not initiate further uplink transmission because trigger A has been invalidated when the first trigger B has already triggered uplink transmission.

[0205] In the description of the foregoing embodiments, two-phase uplink radio resource scheduling was described for a cell in a communication system. It should be noted that this two-phase uplink radio resource scheduling is possible not only for unlicensed or licensed cells, but also for any cell that supports two-phase uplink radio resource scheduling.

[0206] According to another embodiment implemented in the environment of standard TS 36.213, section 8.0 recommends specifying in the standard:

[0207] For a UE serving cell as an LAA SCell, it should

[0208] • When a PDCCH / EPDCCH with DCI format 0A / 0B / 4A / 4B is detected in subframe n intended for use by the UE, and the 'PUSCH Trigger A' field is set to '0', or

[0209] · Within subframes n-v+1 and n-1, the intended use is for the 'trigger PUSCH trigger B' word that is not set to "1". Segment triggered In the most recent subframe starting from subframe nv, the UE detected a PDCCH / EPDCCH with DCI format 0A / 0B / 4A / 4B and 'PUSCH trigger A'.

[0210] When the field is set to '0', and when a DCICRC scrambled by CC-RNTI is detected in subframe n, and the 'PUSCH trigger B' field is set to '1'.

[0211] According to PDCCH / EPDCCH and [...], in subframe n+1+k+i (i=0,1,...,N-1), the corresponding PUSCH transmission is performed according to the channel access procedure described in Section 15.2.1.

[0212] The hardware and software implementation methods disclosed herein

[0213] Other exemplary embodiments relate to the use of hardware, software, or software and hardware collaboration to implement the various embodiments described above. In this regard, user terminals (mobile terminals) and eNodeBs (base stations) are provided. The user terminals and base stations are adapted to perform the methods described herein, including appropriate entities such as receiving units, transmitting units, and processing units that participate in the methods.

[0214] It is further recognized that various embodiments can be implemented or executed using computing devices (processing units). Computing devices or processing units can be, for example, general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices. Various embodiments can also be executed or embodied by combinations of these devices. Specifically, each functional block used in the description of each of the above embodiments can be implemented as an integrated circuit by an LSI. They can be formed individually as chips, or they can be formed as a single chip to include some or all of the functional blocks. They can include data inputs and outputs coupled thereto. Depending on the level of integration, the LSI here can be referred to as an IC, system LSI, super LSI, or very large LSI. However, the technology for implementing integrated circuits is not limited to LSIs and can be implemented using dedicated circuits or general-purpose processors. Additionally, FPGAs (Field-Programmable Gate Arrays) that can be programmed after the LSI is manufactured, or reconfigurable processors that can reconfigure the connections and settings of the circuit cells within the LSI, can be used.

[0215] Furthermore, various embodiments can also be implemented using software modules, which are executed by a processor or directly in hardware. Combinations of software modules and hardware implementations are also possible. Software modules can be stored on any type of computer-readable storage medium, such as RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROMs, DVDs, etc. It should be further noted that various features of different embodiments can be used individually or in any combination as the subject matter of another embodiment.

[0216] Those skilled in the art will understand that many variations and / or modifications can be made to the present disclosure shown in the specific embodiments. Therefore, this embodiment should be considered illustrative rather than restrictive in all respects.

Claims

1. An integrated circuit configured to operate a user equipment, the integrated circuit comprising: The receiving circuit receives data from the radio base station. The first-phase uplink resource scheduling message indicates that the user equipment can use uplink radio resources for uplink transmission via unlicensed cells, and The second-stage uplink resource scheduling message related to the first-stage uplink resource scheduling message; A control circuit, coupled to the receiving circuit, determines that the first stage uplink resource scheduling message is valid in response to the fact that the uplink transmission has not been triggered by another second stage uplink resource scheduling message within a defined time period prior to the reception of the second stage uplink resource scheduling message. as well as The transmitting circuit, coupled to the control circuit, performs the uplink transmission via the unlicensed cell in response to a first-phase uplink resource scheduling message that is determined to be valid.

2. The integrated circuit according to claim 1, wherein, The control circuit responds to the uplink transmission being triggered by the other second-stage uplink resource scheduling message within the defined time period, thereby invalidating the first-stage uplink resource scheduling message.

3. The integrated circuit according to claim 1, wherein, The first-stage uplink resource scheduling message is addressed to the user equipment, and the second-stage uplink resource scheduling message is jointly addressed to multiple user equipments that receive the second-stage uplink resource scheduling message.

4. The integrated circuit according to claim 3, wherein, The first-stage uplink resource scheduling message addresses the user equipment through a user equipment-specific identifier used in the transmission of the first-stage uplink resource scheduling message, wherein the user equipment-specific identifier is configurable.

5. The integrated circuit according to claim 3, wherein, The second-stage uplink resource scheduling message addresses multiple user equipments receiving the second-stage uplink resource scheduling message by using a shared identifier used in the transmission of the second-stage uplink resource scheduling message, wherein the shared identifier is predefined and common to the multiple user equipments.

6. The integrated circuit according to claim 1, wherein, The first phase uplink resource scheduling message indicates the defined time period.

7. The integrated circuit according to claim 1, wherein, The first-phase uplink resource scheduling message also indicates a first time offset to be considered when performing the uplink transmission.

8. The integrated circuit according to claim 7, wherein, The second-stage uplink resource scheduling message indicates the second time offset to be considered when performing uplink transmissions.

9. The integrated circuit according to claim 8, wherein, Upon receiving the second-stage uplink resource scheduling message, the transmitting circuit performs uplink transmission at least after the sum of the first time offset and the second time offset.

10. The integrated circuit according to claim 1, wherein, The first-stage uplink resource scheduling message is a downlink control information (DCI) message in the format of 0A, 0B, 4A, or 4B, which includes a first-stage flag indicating that the DCI message is a two-stage uplink resource scheduling message.

11. The integrated circuit according to claim 10, wherein, The second-stage uplink resource scheduling message is a DCI message in 1C format, including a second-stage flag indicating that the DCI message is a second uplink resource scheduling message of the two-stage uplink resource scheduling.

12. A radio base station for scheduling uplink radio resources, wherein, At least one unlicensed cell is configured for communication between a user equipment and a radio base station for scheduling uplink radio resources on the unlicensed cell, wherein the radio base station includes: The transmitting unit sends a first-stage uplink resource scheduling message to the user equipment, the first-stage uplink resource scheduling message indicating that the user equipment has uplink radio resources available for uplink transmission via the unlicensed cell. The sending unit sends a second-stage uplink resource scheduling message related to the first-stage uplink resource scheduling message to the user equipment. The determination of whether the first-stage uplink resource scheduling message is valid is based on whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to the receipt of the second-stage uplink resource scheduling message at the user equipment. The receiving unit performs uplink reception via the unlicensed cell.

13. The radio base station according to claim 12, wherein, The determination is that the first stage uplink resource scheduling message is valid if no uplink transmission has been triggered by the other second stage uplink resource scheduling message within a predetermined time period prior to the receipt of the second stage uplink resource scheduling message.

14. The radio base station according to claim 12, wherein, If, within a predetermined time period prior to the receipt of the second-stage uplink resource scheduling message, uplink transmission has already been triggered by the other second-stage uplink resource scheduling message, the determination to invalidate the first-stage uplink resource scheduling message is made. Specifically, when the first-stage uplink resource scheduling message is not invalidated, it is determined that the first-stage uplink resource scheduling message is valid.

15. The radio base station according to any one of claims 12 to 14, wherein, The first-stage uplink resource scheduling message is addressed to the user equipment, and the second-stage uplink resource scheduling message is commonly addressed to multiple user equipments receiving the second-stage uplink resource scheduling message. Wherein, the first-stage uplink resource scheduling message addresses the user equipment (UE) through a user equipment-specific identifier used in the transmission of the first-stage uplink resource scheduling message, and wherein the user equipment-specific identifier is configurable; and / or In this process, the second-stage uplink resource scheduling message addresses multiple user equipments receiving the second-stage uplink resource scheduling message through a shared identifier used in the transmission of the second-stage uplink resource scheduling message. The shared identifier is predefined and common to the multiple user equipments.

16. The radio base station according to any one of claims 12 to 14, wherein, The first-stage uplink resource scheduling message indication can be considered together with the sent second-stage uplink resource scheduling message, taking into account the predetermined time period of the first-stage uplink resource scheduling message, and / or Wherein, if the second stage uplink resource scheduling message is received within a predetermined time period indicated after the first stage uplink resource scheduling message is received, the determination is that the first stage uplink resource scheduling message and the second stage uplink resource scheduling message are considered together.

17. A method implemented in a radio base station for scheduling uplink radio resources, wherein, At least one unlicensed cell is configured for communication between a user equipment and a radio base station for scheduling uplink radio resources on the unlicensed cell, wherein the method includes: A first-phase uplink resource scheduling message is sent to the user equipment, indicating that the user equipment has uplink radio resources available for uplink transmission via the unlicensed cell. Send a second-stage uplink resource scheduling message related to the first-stage uplink resource scheduling message to the user equipment. The determination of whether the first-stage uplink resource scheduling message is valid is based on whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to the receipt of the second-stage uplink resource scheduling message at the user equipment. Uplink reception is performed via the unlicensed cell.

18. An integrated circuit for controlling a process of scheduling uplink radio resources by a radio base station, wherein at least one unlicensed cell is configured for communication between a user equipment and a radio base station for scheduling uplink radio resources on the unlicensed cell, wherein, The process includes: A first-phase uplink resource scheduling message is sent to the user equipment, indicating that the user equipment has uplink radio resources available for uplink transmission via the unlicensed cell. Send a second-stage uplink resource scheduling message related to the first-stage uplink resource scheduling message to the user equipment. The determination of whether the first-stage uplink resource scheduling message is valid is based on whether the uplink transmission has been triggered by another second-stage uplink resource scheduling message within a predetermined time period prior to the receipt of the second-stage uplink resource scheduling message at the user equipment. Uplink reception is performed via the unlicensed cell.

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