Integrated circuits that control user equipment

Abstract

To use multiple subframe allocation while providing a minimum unit of efficient control information.SOLUTION: The present disclosure relates to codeword activation / deactivation in multi-subframe grant. Specifically, even in a case where other control parameters including resource allocation are executed for a plurality of subframes, it is possible to activate / deactivate a codeword dynamically and in units of subframe. A signal from a scheduling entity to a scheduled entity includes control information including common resource grant for a plurality of subframes and a plurality of codewords of each subframe, and codeword indication information indicating activation / deactivation of the codeword of each of the plurality of subframes. For each subframe, it is determined whether or not the codeword in the subframe is enabled or disabled according to the codeword indication information and / or which codeword is enabled or disabled.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to signaling of scheduling information in communication systems having multiple subframes, and in particular to apparatus, methods and signals for implementing such signaling. [Background technology]

[0002] [Long Term Evolution (LTE)] Third generation mobile communication systems (3G), based on WCDMA radio access technology, are being widely deployed around the world. As a first step in enhancing or evolving this technology, High-Speed ​​Downlink Packet Access (HSDPA) and an enhanced uplink (also called High-Speed ​​Uplink Packet Access (HSUPA)) have been introduced, providing a highly competitive radio access technology.

[0003] To meet the ever-increasing demands of users and to ensure competitiveness against new radio access technologies, 3GPP has introduced a new mobile communications system called Long Term Evolution (LTE). LTE is designed to accommodate carrier demands for high-speed data and media transmissions, as well as high-capacity voice support, over the next decade. The ability to deliver high bit rates is a key feature of LTE.

[0004] The LTE system is an efficient packet-based radio access and radio access network that provides full IP-based functionality with low latency and low cost. LTE specifies multiple scalable transmission bandwidths (e.g., 1.4 MHz, 3.0 MHz, 5.0 MHz, 10.0 MHz, 15.0 MHz, and 20.0 MHz) to achieve flexible system deployment using a given spectrum. Orthogonal Frequency Division Multiplexing (OFDM)-based radio access is adopted for the downlink because it is inherently less susceptible to multipath interference (MPI) due to its low symbol rate, uses a cyclic prefix (CP), and supports various transmission bandwidth configurations. Single-Carrier Frequency Division Multiple Access (SC-FDMA)-based radio access is adopted for the uplink. This is because, given the limited transmit power of User Equipment (UE), providing a wider coverage area takes priority over improving peak data rates. LTE Release 8 / 9 adopts a number of key packet radio access technologies (e.g., Multiple Input Multiple Output (MIMO) channel transmission technology) to achieve a highly efficient control signaling structure.

[0005] [LTE architecture] Figure 1 shows the overall architecture of LTE. E-UTRAN consists of eNodeBs, which terminate E-UTRA's user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) protocols for 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 functions. The eNB also provides radio resource control (RRC) functions for the control plane. The eNB performs many functions, including radio resource management, admission control, scheduling, negotiated uplink quality of service (QoS), cell information broadcasting, encryption / decryption of user and control plane data, and compression / decompression of downlink and uplink user plane packet headers. The Radio Resource Control (RRC) layer controls the communication between UEs and eNBs over the radio interface and the mobility of UEs moving across several cells. The RRC protocol also supports the transmission of NAS information. For a UE in RRC_IDLE, RRC supports notification of incoming calls from the network. RRC connection control covers all procedures related to the establishment, modification and release of an RRC connection, including paging, measurement configuration and reporting, radio resource configuration, initial security activation, and establishment of signaling radio bearers (SRBs) and radio bearers carrying user data (data radio bearers (DRBs)). Multiple eNodeBs are connected to each other via the X2 interface.

[0006] In addition, multiple eNodeBs are connected to the EPC (Evolved Packet Core) via the S1 interface, more specifically to the MME (Mobility Management Entity) via the S1-MME and to the Serving Gateway (SGW) via the S1-U. The S1 interface supports a many-to-many relationship between the MME / Serving Gateway and the eNodeBs. The SGW routes and forwards user data packets while also serving as a mobility anchor for the user plane during handovers between eNodeBs. Furthermore, the SGW serves as an anchor for mobility between LTE and other 3GPP technologies (terminating the S4 interface and relaying traffic between 2G / 3G systems and PDN GWs). 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 (e.g., IP bearer service parameters or network internal routing information). Furthermore, the SGW performs duplication of user traffic in case of lawful interception.

[0007] The MME is the main control node of the LTE access network. It is responsible for idle mode user equipment tracking and paging procedures (including retransmissions). It is involved in the bearer activation / deactivation process. Furthermore, the MME is responsible for selecting the SGW for the user equipment during initial attach and during intra-LTE handovers involving Core Network (CN) node relocation. The MME is responsible for authenticating the user (by interacting with the HSS). Non-Access Stratum (NAS) signaling terminates in the MME. The MME is also responsible for generating and assigning temporary identities to user equipment. The MME checks the user equipment's authorization to enter the service provider's Public Land Mobile Network (PLMN) and enforces user equipment roaming restrictions. The MME is the termination point in the network for ciphering / integrity protection of NAS signaling and is responsible for security key management. Lawful interception of signaling is also supported by the MME. The MME also provides the control plane function for mobility between LTE and 2G / 3G access networks, terminating the S3 interface from the SGSN, and the S6a interface towards the home HSS for roaming user equipment.

[0008] [Component carrier structure in LTE] The downlink component carrier of a 3GPP LTE system is further divided in the time-frequency domain in so-called subframes. In 3GPP LTE, each subframe is divided into two downlink slots as shown in Figure 2A. The first downlink slot comprises a control channel region (PDCCH region) within the first OFDM symbol. Each subframe consists of a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Release 8)), each OFDM symbol spanning the entire bandwidth of the component carrier. Each OFDM symbol therefore consists of several modulation symbols transmitted on each subcarrier. In LTE, the transmitted signal in each slot is divided into N DL RB ×N RB sc Book Subcarrier and N DL symb is described by a resource grid of N OFDM symbols. DL RB is the number of resource blocks in the bandwidth. N DL RB depends on the downlink transmission bandwidth configured in the cell, and N min,DL RB ≦N DL RB ≦N max,DL RB In this case, N min,DL RB =6 and N max,DL RB = 110 are the minimum and maximum downlink bandwidths, respectively, supported by the current version of the specification. RB sc is the number of subcarriers in one resource block. In the case of a normal cyclic prefix subframe structure, N RB sc =12, N DL symb = 7. For the uplink, the grid shown in Figure 2B is provided, and in this respect reference is also made to Figures 6.2.2-1 and 5.2.1-1 of Non-Patent Document 1.

[0009] Considering a multi-carrier communication system using, for example, OFDM, as used in 3GPP LTE, the smallest unit of resource that can be allocated by a scheduler is one "resource block." A physical resource block (PRB) is defined as consecutive OFDM symbols in the time domain (e.g., seven OFDM symbols) and consecutive subcarriers in the frequency domain (e.g., 12 subcarriers of a component carrier), as illustrated in Figure 2. Thus, in 3GPP LTE (Release 8), a physical resource block consists of resource elements and corresponds to one slot in the time domain and 180 kHz in the frequency domain (for further details on the downlink resource grid, see, for example, Section 6.2 of 3GPP LTE 2013-01-10, e.g., version 8.9.0, available on the 3GPP website and incorporated herein by reference).

[0010] A subframe consists of two slots. There are 14 OFDM symbols in a subframe when the so-called "normal" CP (Cyclic Prefix) is used, and 12 OFDM symbols in a subframe when the so-called "extended" CP is used. For the purposes of terminology, in the following, a time-frequency resource equivalent to the same consecutive subcarriers spread across an entire subframe will be called a "resource block pair" or equivalently an "RB pair" or "PRB pair".

[0011] The term "Component Carrier" denotes a combination of several resource blocks in the frequency domain. In future releases of LTE, the term "Component Carrier" will no longer be used, and instead the terminology will be changed to "Cell" to denote a combination of downlink and optionally uplink resources. The linking between the carrier frequencies of the downlink resources and the carrier frequencies of the uplink resources is indicated in system information transmitted on the downlink resources.

[0012] Similar assumptions regarding the structure of component carriers will apply to subsequent releases.

[0013] [Carrier aggregation in LTE-A to support wider bandwidths] The LTE-Advanced system can support a bandwidth of 100 MHz, while the LTE system can only support 20 MHz. Carrier aggregation aggregates two or more component carriers to support a wider transmission bandwidth of up to 100 MHz. In the LTE-Advanced system, several cells in the LTE system are aggregated into a wider channel. This channel is wide enough for 100 MHz, even if these cells in the LTE system are in different frequency bands. A user equipment can simultaneously receive or transmit on one or multiple component carriers (corresponding to multiple serving cells) depending on the user equipment's capabilities. Carrier aggregation is supported for both contiguous and non-contiguous component carriers, with each component carrier limited to a maximum of 110 resource blocks in the frequency domain (using 3GPP LTE (Release 8 / 9) numerology).

[0014] When carrier aggregation is configured, the mobile terminal has only one RRC connection with the network. During RRC connection establishment / re-establishment, one cell provides security inputs (one ECGI, one PCI, and one ARFCN) and non-access stratum (NAS) mobility information (e.g., TAI), similar to LTE Release 8 / 9. After RRC connection establishment / re-establishment, the component carrier corresponding to that cell is called the downlink primary cell (PCell). In the connected state, one downlink PCell (DL PCell) and one uplink PCell (UL PCell) are always configured per user equipment. In the configured set of component carriers, other cells are called secondary cells (SCells), and the carriers of the SCells are downlink secondary component carriers (DL SCCs) and uplink secondary component carriers (UL SCCs). Up to five serving cells (including the PCell) can be configured for one UE.

[0015] [LTE uplink access method] For uplink transmission, user terminals must transmit with high power efficiency to maximize coverage. Single-carrier transmission combined with FDMA for dynamic bandwidth allocation has been selected as the uplink transmission scheme for E-UTRA. Single-carrier transmission was primarily chosen due to its lower peak-to-average power ratio (PAPR) compared to multi-carrier signals (OFDMA), resulting in a corresponding improvement in power amplifier efficiency and improved coverage (higher data rates for a given terminal peak power). In each time interval, the eNodeB assigns each user a unique time / frequency resource for transmitting user data, ensuring intra-cell orthogonality. Orthogonal multiple access in the uplink improves spectral efficiency by eliminating intra-cell interference. Interference due to multipath propagation is addressed at the base station (eNodeB) by inserting a cyclic prefix into the transmitted signal.

[0016] The basic physical resource used to transmit data is a block of size BW over one time interval (e.g., a subframe). grant (The coded information bits are mapped to this resource.) A subframe (also called a Transmission Time Interval (TTI)) is the minimum time interval for transmitting user data. However, by concatenating subframes, a frequency resource BW that spans a period longer than one TTI can be created. grant It is also possible to assign a user

[0017] [Layer 1 / Layer 2 control signaling] L1 / L2 control signaling is transmitted in the downlink together with data to inform scheduled users of their allocation status, transport format, and other transmission-related information (e.g., HARQ information, Transmit Power Control (TPC) commands). L1 / L2 control signaling is multiplexed with downlink data within a subframe (assuming user allocation can vary from subframe to subframe). Note that user allocation can also be performed on a TTI (Transmission Time Interval) basis, where the TTI length can be an integer multiple of a subframe. The TTI length can be constant for all users within a service area, different for different users, or even dynamic for each user. L1 / L2 control signaling typically only needs to be transmitted once per TTI. Without loss of generality, we assume that a TTI is equal to one subframe in the following.

[0018] L1 / L2 control signaling is transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH carries messages as Downlink Control Information (DCI). DCI mostly contains resource allocations for mobile terminals or groups of UEs and other control information. Typically, several PDCCHs can be transmitted within one subframe.

[0019] It should be noted that in 3GPP LTE, assignments for uplink data transmissions (also referred to as uplink scheduling grants or uplink resource assignments) are also transmitted on the PDCCH. Furthermore, Release 11 introduced the EPDCCH, which essentially performs the same function as the PDCCH (i.e., carries Layer 1 / Layer 2 control signaling), although the details of the transmission method differ from those of the PDCCH. Further details can be found, inter alia, in the current versions (e.g., version 13.2.0) of 3GPP LTE Standards Track [Page 1] and 3GPP LTE Standards Track [Page 2] (freely available on the 3GPP website and incorporated herein by reference). Therefore, most of the items outlined in the Background section and in the embodiments apply to the PDCCH and EPDCCH or other means of carrying Layer 1 / Layer 2 control signaling, unless otherwise stated.

[0020] The information sent in L1 / L2 control signaling for the purpose of allocating uplink or downlink radio resources (especially in LTE(-A) Release 10) can generally be categorized into the following items: - User Identity: Indicates the user to whom the allocation is made. This information is typically included in the checksum by masking the CRC with the user's identity. - Resource allocation information: indicates the resources (e.g., resource blocks (RBs)) allocated to a user. This information is also called resource block assignment (RBA). Note that the number of resource blocks (RBs) allocated to a user can be dynamic. Carrier indicator: Used when a control channel transmitted on a first carrier allocates resources related to a second carrier (i.e. resources of or related to the second carrier) (cross-carrier scheduling). - Modulation and Coding Scheme: Determines the modulation scheme and coding rate to be used. - HARQ information: such as New Data Indicator (NDI) or Redundancy Version (RV), which are particularly useful when retransmitting a data packet or part of it. - Power control command: adjusts the transmit power of the assigned uplink data or control information transmission. - Reference signal information: such as the applied cyclic shift or orthogonal cover code (OCC) index used to transmit or receive the reference signal to be allocated. - Uplink assignment index or downlink assignment index: Used to identify the order of assignments, and is particularly useful in TDD systems. - Hopping information: e.g., information indicating whether and how resource hopping is applied in order to increase frequency diversity. - CSI Request: Used to trigger the transmission of Channel State Information in the allocated resources. - Multi-cluster information: A flag used to indicate and control whether transmission is to occur in a single cluster (a contiguous set of RBs) or in multiple clusters (at least two discontinuous sets of contiguous resource blocks). Multi-cluster allocation was introduced in 3GPP LTE-(A) Release 10.

[0021] It should be noted that the above list is not exhaustive and that depending on the DCI format used, not all of the listed information items need to be included in each PDCCH transmission.

[0022] In the current LTE specification (Release 13), the modulation and coding scheme (MCS) is determined by the parameters modulation order, transport block size (TBS), and the number of resource elements (RE) used to transmit the transport block.

[0023] The modulation orders (number of bits per modulation symbol) supported in LTE in licensed bands include 2, 4, 6, and 8, which correspond to QPSK, 16QAM, 64QAM, and 256QAM, respectively. It has not yet been considered whether all of these will be supported in unlicensed band operation, but it would be advantageous if the same set of modulation orders were supported in unlicensed band operation.

[0024] As described in 3GPP TS 36.110, section 7.1.7 (available on the 3GPP website), the TBS (Transport Block Size) is determined by the TBS index according to the MCS index indicated to the UE in the DCI and the number of PRBs (Physical Resource Blocks) allocated for the transmission of the PDSCH. The LTE specification (3GPP TS 36.110, section 7.1.7.2) includes a two-dimensional TBS table, where the TBS index indicates the row and the number of scheduled PRBs indicates the column. This table specifies the transport block size (and therefore the applicable coding and puncturing).

[0025] Figure 5 shows an uplink MCS table that assigns MCS and / or redundancy versions to 32 values ​​0-31. Specifically, the first column represents the MCS index included in the DCI. Each MCS index 0-28 is associated with a specific combination of modulation order (2 = QPSK, 4 = 16QAM, 6 = 64QAM), transport block size (TBS) index, and redundancy version index. MCS indexes (values) 29-31 are not associated with a specific modulation order or coding scheme (TBS index) in the uplink and define redundancy versions 1-3, assuming that the modulation and coding scheme remains the same as in the previous transmission of the same transport block (e.g., redundancy version 0).

[0026] The redundancy version (RV) specifies the starting point in the circular (re)transmit buffer from which to begin the read operation. For the first transmission, which primarily sends systematic bits, RV=0 is usually chosen because this method offers a good compromise between successful decoding at high signal-to-noise ratios (SNRs) and successful decoding at low SNRs. The scheduler can choose different RVs for transmissions of the same packet to support both incremental redundancy (IR) combining and Chase combining. Four redundancy versions are currently defined, each characterized by its starting position, numbered 0 through 3. The usual order of these RVs for the first transmission and subsequent retransmissions is 0, 2, 3, 1.

[0027] Downlink control information comes in several formats, which differ in their overall size and the information contained in the above-mentioned fields. The various DCI formats currently defined in LTE are as follows and are described in detail in 3GPP TS 2.0, section 5.3.3.1 (current version 13.2.0, available on the 3GPP website and incorporated herein by reference). For further details regarding DCI formats and the specific information transmitted in the DCI, please refer to the above-mentioned technical standards or to 3GPP TS 2.0, section 9.3 (incorporated herein by reference). - Format 0: DCI format 0 is used for transmitting resource grants for the PUSCH using single-antenna port transmission in uplink transmission mode 1 or 2. - Format 1: DCI Format 1 is used for transmitting resource allocations for single codeword PDSCH transmissions (downlink transmission modes 1, 2, 7). - Format 1A: DCI Format 1A is used for compact signaling of resource allocation for single codeword PDSCH transmissions and for allocating dedicated preamble signatures to mobile terminals for contention-free random access (all transmission modes). - Format 1B: DCI Format 1B is used to compactly signal resource allocation for PDSCH transmission using closed-loop precoding with rank-1 transmission (downlink transmission mode 6). The transmitted information is the same as in Format 1A, but in addition includes an indicator of the precoding vector applied to the PDSCH transmission. - Format 1C: DCI Format 1C is used for very compact transmission of PDSCH allocations. When Format 1C is used, PDSCH transmissions are restricted to the use of QPSK modulation. This format is used, for example, to signal paging messages or to broadcast system information messages. - Format 1D: DCI Format 1D is used to compactly signal resource allocation for PDSCH transmission using multi-user MIMO. The transmitted information is the same as in Format 1B, but instead of one of the bits for the precoding vector indicator, there is one bit to indicate whether a power offset is applied to the data symbols. This feature is necessary to indicate whether the transmit power is shared between two UEs. In future versions of LTE, this feature can be extended to power sharing between a larger number of UEs. - Format 2: DCI format 2 is used to transmit resource allocations for PDSCH in case of closed-loop MIMO operation (transmission mode 4). - Format 2A: DCI Format 2A is used to transmit resource allocations for PDSCH in case of open-loop MIMO operation. The transmitted information is the same as in Format 2, with the exception that if the eNodeB has two transmit antenna ports, there is no precoding information, and in case of four antenna ports, two bits are used to indicate the transmission rank (transmission mode 3). - Format 2B: Introduced in Release 9 and used to transmit resource allocations for PDSCH in case of dual layer beamforming (transmission mode 8). - Format 2C: Introduced in Release 10 and used to transmit resource allocations for PDSCH in case of closed-loop single-user MIMO operation or multi-user MIMO operation (up to 8 layers) (transmission mode 9). - Format 2D: Introduced in Release 11 and used for transmission of up to 8 layers. Mainly used in CoMP (Cooperative Multipoint) (transmission mode 10). - Formats 3 and 3A: DCI formats 3 and 3A are used to transmit power control commands for PUCCH and PUSCH with 2-bit or 1-bit power adjustment, respectively. These DCI formats contain individual power control commands for groups of UEs. - Format 4: DCI format 4 is used for scheduling PUSCH using closed-loop spatial multiplexing transmission in uplink transmission mode 2.

[0028] The PDCCH carries DCI in a set of one or more consecutive control channel elements (CCEs), which correspond to nine resource element groups (REGs), each consisting of four or six resource elements.

[0029] A search space indicates a set of CCE locations where a UE can find a PDCCH for itself. Each PDCCH carries one DCI and is identified by an RNTI (Radio Network Temporary Identifier) ​​implicitly coded in a CRC attached to the DCI. The UE monitors the CCEs of the configured search space(s) by blind decoding and checking the CRC.

[0030] The search spaces can be a common search space and a UE-specific search space. The UE needs to monitor both the common search space and the UE-specific search space, which may overlap. The common search space carries DCI that is common to all UEs, such as system information (using the SI-RNTI), paging (P-RNTI), PRACH response (RA-RNTI), or UL TPC commands (TPC-PUCCH / PUSCH-RNTI). The UE-specific search space carries DCI for UE-specific assignment (using the C-RNTI allocated to the UE), semi-persistent scheduling (SPS C-RNTI), or initial assignment (temporary C-RNTI).

[0031] While traditional wireless communications (single-input single-output (SISO)) utilizes time- or frequency-domain preprocessing of transmitted data and time- or frequency-domain decoding of received data, the use of additional antenna elements at either the base station (eNodeB) or user equipment (UE) side (in the downlink or uplink) opens an additional spatial dimension for signal precoding and detection. Space-time processing techniques exploit this dimension with the goal of improving link performance in terms of one or more possible metrics, such as error rate, communication data rate, coverage area, and spectral efficiency (units: bps / Hz / cell). These techniques are classified as single-input multiple-output (SIMO), multiple-input single-output (MISO), or multiple-input multiple-output (MIMO), depending on whether multiple antennas are available at the transmitter and / or receiver. A point-to-point multi-antenna link between a base station and one UE is called Single-User MIMO (SU-MIMO), while Multi-User MIMO (MU-MIMO) is characterized by several UEs simultaneously communicating with a common base station using the same frequency and time domain resources.

[0032] The LTE standard defines so-called "antenna ports" (see section 5.2.1 of 3GPP TS 2.0, 2013). Antenna ports do not correspond to physical antennas, but are logical entities distinguished by their reference signal sequences. Multiple antenna port signals can be transmitted by one transmit antenna. Correspondingly, one antenna port can be spread over multiple transmit antennas.

[0033] "Spatial layer" is a term used in LTE to describe one of the different streams generated by spatial multiplexing. A layer can be described as a mapping of symbols to transmit antenna ports. Each layer is identified by a precoding vector of size equal to the number of transmit antenna ports and can be associated with a radiation pattern. The rank of the transmission is the number of layers transmitted.

[0034] A "codeword" is an independently coded data block that corresponds to one transport block (TB) passed from the transmitter's Medium Access Control (MAC) layer to the physical layer and is protected by a CRC. For ranks greater than or equal to 2, two codewords can be transmitted. The number of codewords is always less than or equal to the number of layers, which is always less than or equal to the number of antenna ports. It is possible to map transport block 1 to codeword 0 and transport block 2 to codeword 1, or alternatively, to map transport block 2 to codeword 0 and transport block 1 to codeword 1.

[0035] To enable rapid rank and precoder adaptation in downlink transmission mode, the UE can be configured to feed back a Rank Indicator (RI) together with a Precoding Matrix Indicator (PMI), which indicates the preferred RI / PMI based on the measured quality. Meanwhile, the eNB indicates via a Transmitted Precoding Matrix Indicator (TPMI) in the downlink assignment message on the PDCCH whether it is applying the UE's preferred precoder, and if not, which precoder is being used. This allows the UE to derive the correct phase reference for the cell-specific reference signal for demodulating the PDSCH data.

[0036] Similarly, the eNB can control the rank and precoder in the uplink transmission mode. Unlike the downlink, there is no explicit feedback by the UE, such as RI and PMI. The eNB obtains transmitted reference symbols (e.g., demodulation reference symbols or sounding reference symbols) from the uplink transmission and uses these reference signals to determine the appropriate number of transmitted layers and TPMI, which it indicates in an uplink resource allocation message (DCI) transmitted on a control channel, such as the PDCCH.

[0037] [LTE in Unlicensed Bands: Licensed Assisted Access (LAA)] A work item addressing LTE specifications for operation in unlicensed spectrum was initiated in June 2015. The reasons for extending LTE into unlicensed spectrum are the limited amount of licensed spectrum and the growing demand for wireless broadband data. Therefore, unlicensed spectrum is increasingly viewed by mobile operators as a supplemental means to expand their service offerings. Compared to relying on other radio access technologies (RATs) such as Wi-Fi, the advantage of LTE in unlicensed spectrum is that operators and vendors can leverage existing and future investments in LTE / EPC hardware in the radio and core network by supplementing their LTE platforms with access to unlicensed spectrum.

[0038] However, it must be taken into account that access to unlicensed spectrum will necessarily coexist with other radio access technologies (RATs) in unlicensed spectrum and can never match the quality of licensed spectrum access. Therefore, LTE operation in unlicensed spectrum will, at least initially, be seen as a complement to LTE in licensed spectrum rather than a standalone operation in unlicensed spectrum. Based on this assumption, 3GPP has established the term Licensed Assisted Access (LAA) for the operation of LTE in unlicensed spectrum in conjunction with at least one licensed spectrum. However, this does not preclude future standalone operation of LTE in unlicensed spectrum without relying on Licensed Assisted Access (LAA).

[0039] The current general LAA method in 3GPP is to make full use of the already established carrier aggregation (CA) framework of Release 12, which, as mentioned above, includes a so-called primary cell (PCell) carrier and one or more secondary cell (SCell) carriers. Carrier aggregation (CA) generally supports both cell self-scheduling (scheduling information and user data are transmitted on the same carrier) and cross-carrier scheduling between cells (scheduling information on PDCCH / EPDCCH and user data on PDSCH / PUSCH are transmitted on different carriers).

[0040] The basic approach envisioned by 3GPP is to operate a PCell in a licensed band while operating one or more SCells in an unlicensed band. The advantage of this approach is that the PCell can be used to reliably transmit control messages and user data (e.g., voice and video) that require high quality of service (QoS). Meanwhile, SCells in unlicensed bands necessarily coexist with other radio access technologies (RATs), which may significantly degrade QoS to varying degrees depending on the scenario. Figure 3 illustrates a very basic scenario, with a licensed PCell, a licensed SCell 1, and various unlicensed SCells 2, 3, and 4 (illustratively depicted as small cells). The transmitting / receiving network nodes for the unlicensed SCells 2, 3, and 4 can be remote radio heads managed by the eNB, or nodes attached to the network but not managed by the eNB. For simplicity, the connections from these nodes to the eNB or the network are not explicitly shown in the figure.

[0041] It has been agreed within 3GPP that the initial phase of LAA (Licensed Assisted Access) studies and specifications will focus on unlicensed bands in 5 GHz. Therefore, one of the most important issues is coexistence with Wi-Fi (IEEE 802.11) systems operating in these unlicensed bands. To support fair coexistence between LTE and other technologies (e.g., Wi-Fi) and to ensure fairness between different LTE operators in the same unlicensed band, LTE channel access procedures for unlicensed band operation must follow a specific set of regulations that depend on the region (Europe, USA, China, Japan, etc.) and the frequency band under consideration. A comprehensive description of the regulatory requirements for operation in the 5 GHz unlicensed band is provided in Non-Patent Document 6 (available on the 3GPP website). The regulatory requirements that must be taken into account when designing the LAA procedure include, depending on the region and band, Dynamic Frequency Selection (DFS), Transmit Power Control (TPC), Listen Before Talk (LBT), and Discontinuous Transmission with limited maximum transmission time. 3GPP's intention is to aim for a single international framework for LAA, which essentially means that all requirements for different regions and the 5 GHz band must be taken into account when designing a system.

[0042] The operation of DFS (Dynamic Frequency Selection) and the corresponding requirements are related to the master / slave principle. To perform radar detection, the master detects radar interference and can rely on another device associated with the master. In accordance with European regulations on LBT (Listen Before Talk), a device must perform a clear channel assessment (CCA) before occupying a radio channel. It is only permitted to start transmitting on an unlicensed channel after the channel has been detected as clear, for example, based on energy detection. During CCA, the device must monitor the channel for a certain minimum time. If the detected energy level exceeds a set CCA threshold, the channel is considered occupied. If the channel is classified as clear, the device is permitted to transmit immediately. This limits the maximum duration of a transmission to promote fair resource sharing with other devices operating in the same band.

[0043] Energy detection in CCA is performed over the entire channel bandwidth (e.g., 20 MHz in the 5 GHz unlicensed band), i.e., the received power levels of all subcarriers of an LTE OFDM symbol within that channel contribute to the energy level estimated in the device performing the CCA.

[0044] Furthermore, the total time a device occupies a given unlicensed channel by continuous transmission without re-evaluating the channel's availability (i.e., LBT / CCA) is defined as the Channel Occupancy Time (see Section 4.8.3.1 of Non-Patent Document 7). The channel occupation time ranges from 1 ms to 10 ms, and the maximum channel occupation time can be, for example, 4 ms as currently defined in Japan. Furthermore, there is also a minimum idle time during which a device is not allowed to occupy an unlicensed channel again after transmitting on it, and the minimum idle time is at least 5% of the previous channel occupation time. For example, a UE can perform a new CCA at the end of an idle period. This transmission behavior is shown schematically in Figure 4.

[0045] [Multiple subframe allocation] In 3GPP RAN1, the possibility of multi-subframe scheduling in uplink LAA has been investigated (see Non-Patent Document 8). As a result, only per-TTI scheduling is allowed, except for semi-persistent scheduling (SPS) and UL grants in TDD UL / DL configuration 0. A downlink or uplink grant received in subframe n schedules only one PDSCH or PUSCH in subframe n+k (for FDD, k=0 in downlink and k=4 in uplink).

[0046] When a scheduled LAA UE receives an UL grant in subframe n, it needs to perform LBT on the scheduled unlicensed carrier to seize the channel before starting PUSCH transmission in subframe n+4 based on the FDD HARQ timing. The eNB cannot predict the result of LTB on the UE side when sending an UL grant in subframe n, and has no choice but to send an UL grant assuming that the UE will occupy the channel for the PUSCH scheduled in subframe n+4. However, if the UE cannot complete the LBT required for uplink transmission in time, the scheduled PUSCH cannot be transmitted in the scheduled subframe. This results in wasted resources for the UL grant as well as wasted UL resources for PUSCH transmission. LAA UL transmission should be designed to increase channel access opportunities for LAA with less scheduling overhead.

[0047] To increase channel access opportunities while minimizing the signaling overhead for scheduling PUSCH on unlicensed carriers, multi-subframe scheduling is considered. In multi-subframe scheduling, if a UE successfully completes LBT, it can transmit PUSCH in one or more subframes in the scheduled subframe with one UL grant. When DL demand is low but UL demand is high, it is advantageous to support multi-subframe scheduling to avoid unnecessary DL transmissions for sending UL grants. In this case, not only is the signaling overhead for sending UL grants saved, but the overall interference with other nodes is reduced. [Prior art documents] [Non-patent literature]

[0048] [Non-Patent Document 1] 3GPP TS 36.211, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation”, from June 2016 v. 13.2.0 [Non-licensed document 2] 3GPP TS 36.211, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)” [Non-licensed document 3] 3GPP TS 36.213, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures”, v13.2.0

Non-licensed Document 4

Non-licensed Document 5

Non-licensed Document 6

Non-licensed Document 7

[0049] One non-limiting exemplary embodiment provides an apparatus and method for using multi-subframe allocation while still providing efficient control information granularity. [Means for solving the problem]

[0050] In one general aspect, the techniques disclosed herein provide an apparatus for receiving a resource grant for a plurality of subframes in a communications system, the apparatus comprising: a transceiver configured to receive a signal comprising: a resource grant for the plurality of subframes and a plurality of codewords in each subframe; precoding indication information common to the plurality of subframes; and a modulation and coding scheme (MCS) indicator that is common to the plurality of granted subframes and individual for each of the plurality of codewords, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of a plurality of MCSs and at least one value that does not indicate an MCS; and a processing device configured to determine to disable a codeword from a plurality of codewords in the plurality of subframes if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS, and to determine not to disable a codeword from a plurality of codewords in the plurality of subframes if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS, and otherwise determine not to disable a codeword from a plurality of codewords in the plurality of subframes.

[0051] In another general aspect, the techniques disclosed herein provide an apparatus for receiving a resource grant for a plurality of subframes in a communication system, the apparatus including: a transceiver that receives a signal comprising control information including a common resource grant for the plurality of subframes and a plurality of codewords in each subframe and codeword indication information indicating enabling or disabling of one or more codewords in each of the plurality of subframes; and a processing device that is configured to determine, for each subframe, whether and / or which codewords from the plurality of codewords in that subframe are enabled or disabled in accordance with the codeword indication information.

[0052] It should be noted that the general or specific embodiments may be embodied as a signal, a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof.

[0053] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. These benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and drawings, and it is not necessary for all of the embodiments and features to be present in order to obtain one or more of such benefits and / or advantages.

[0054] Exemplary embodiments are described in more detail below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0055] [Figure 1] 1 illustrates an example architecture of a 3GPP LTE system. [Figure 2A] 1 illustrates an exemplary downlink resource grid of a downlink slot of a subframe defined in 3GPP LTE (Release 8 / 9). [Figure 2B]1 illustrates an exemplary uplink resource grid of uplink slots of a subframe defined in 3GPP LTE (Release 8 / 9). [Figure 3] 1 illustrates an exemplary scenario of license-assisted access, including various licensed and unlicensed cells. [Figure 4] 1 illustrates a schematic representation of transmission timing in an unlicensed band, including various periods: channel occupation time, idle periods, and fixed frame periods. [Figure 5] 1 is an MCS table showing MCS indices associated with modulation orders and transport block indices, as well as redundancy versions. [Figure 6] 1 is a table summarizing the current design of signaling for multiple subframe allocations. [Figure 7A] 1 is a table showing signaling of MIMO-related information for two antenna ports; [Figure 7B] 1 is a table showing signaling of MIMO-related information for four antenna ports; [Figure 8] FIG. 1 is a block diagram illustrating an apparatus according to an embodiment. [Figure 9A] FIG. 2 is a block diagram illustrating an exemplary OFDM transmitter for the uplink. [Figure 9B] FIG. 2 is a block diagram illustrating an exemplary OFDM transmitter for the downlink. [Figure 10] 1 is a flow chart illustrating a method according to one embodiment. [Figure 11] 1 is a flow chart illustrating a method according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0056] A "mobile station," "mobile node," "user terminal," or "user equipment" is a physical entity in a communication network. A node may have several functional entities. A functional entity refers to a software or hardware module that performs a predetermined set of functions and / or provides a predetermined set of functions to another functional entity of the node or the network. A node may have one or more interfaces that attach the node to communication equipment or communication media, through which the node can communicate. Similarly, a network entity may have logical interfaces that attach functional entities to communication equipment or communication media, through which the network entity can communicate with other functional entities or correspondent nodes.

[0057] The term "radio resource" as used in the claims and in this application should be broadly understood to mean physical radio resources (eg, time-frequency resources).

[0058] The terms "unlicensed cell" or "unlicensed carrier" as used in the claims and in this application should be understood broadly as a cell / carrier in an unlicensed frequency band. Correspondingly, the terms "licensed cell" or "licensed carrier" as used in the claims and in this application should be understood broadly as a cell / carrier in a licensed frequency band. These terms should be understood, exemplarily, in the context of 3GPP as of Release 12 / 13 and the work item "Licensed-Assisted Access."

[0059] A transport block (TB) to be transmitted on the physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) must be prepared before the PDSCH or PUSCH itself can be transmitted. From a specific HARQ process queue in the MAC layer, a specific number of bits (given by the transport block size (TBS)) are taken and passed along with the corresponding MAC header to the underlying PHY (physical layer).

[0060] As discussed above in the Background section, there is a one-to-one mapping between codewords and transport blocks. Whether transport block 1 is mapped to codeword 0 and transport block 2 is mapped to codeword 1, or whether transport block 2 is mapped to codeword 0 and transport block 1 is mapped to codeword 1, is known a priori, either through static rules, configuration, or messages included in the downlink control information. For brevity, this description discusses enabling and disabling codewords. However, it should be understood that this description applies equally to "transport blocks" as well as "codewords." Therefore, it should be understood that the embodiments and examples also apply to enabled / disabled transport blocks in addition to, or instead of, applying to enabled / disabled codewords.

[0061] Figure 6 shows a table summarizing some of the current agreements under consideration within 3GPP regarding dedicated control information (DCI) used for uplink grants applicable to resources granted on unlicensed carriers. Specifically, the left column lists the DCI fields. The center and right columns show DCI Format 0B and DCI Format 4B, respectively, along with the minimum unit at which the DCI fields can be defined in the case of multi-subframe grants. DCI Format 0B and DCI Format 4B are intended to be adjuncts to the currently used DCI Format 0 and DCI Format 4.

[0062] DCI format 4 is currently used for scheduling PUSCH in one UL cell in the case of multi-antenna port transmission mode, and includes, among other things, an MCS index (5 bits) and an NDI (1 bit) for each of two codewords (transport blocks), defined as shown in Figure 5. In addition, a 3-bit or 6-bit precoding information field is included to indicate the TPMI and the number of layers.

[0063] In the table, the term "common" means that the respective DCI field applies to all subframes covered by the multi-subframe grant and to all codewords if multi-layer transmission is applied. For example, the resource allocation field defines the resource blocks allocated per subframe and codeword. In this case, the resource block allocation applies to each of the subframe codewords for each of the multiple subframes.

[0064] DCI Format 0B and DCI Format 4B generally correspond to DCI Format 0 and DCI Format 4 described above, but these DCI Formats 0B and 4B provide multi-subframe grants. That is, DCI Format 0B is applicable to single-antenna port transmission, while DCI Format 4B is applicable to multi-antenna port transmission. As can be seen from the table in FIG. 6, DCI Format 0B only supports one codeword and does not support multi-antenna transmission, and therefore does not convey precoding information. In contrast, DCI Format 4B supports multi-antenna port transmission and therefore can include characteristics of each layer / codeword. Therefore, the usage of some DCI fields in Formats 0B and 4B may differ. In FIG. 6, when multiple codewords are present, it is advantageous to provide a modulation and coding scheme for each codeword. However, providing an MCS for each subframe is considered unnecessary because channel quality is unlikely to change at such a rapid rate and it is not clear whether the eNB would have sufficient information about rapidly changing channel conditions to use such information when transmitting DCI. It is not clear at this time whether and how precoding information will be conveyed by DCI format 4B.

[0065] As can be seen in Figure 6, some of the fields are provided for each of multiple subframes. For example, a new data indicator is required for each subframe because each subframe carries different data (because different TTIs are mapped to each subframe) and therefore each subframe can be retransmitted individually. Correspondingly, a redundancy version is also required on a subframe-by-subframe basis. Note that the redundancy version in legacy DCI formats 0 and 4 is selected from a set of four predefined values. In the table of Figure 6, the redundancy version is a separate field, with one bit per subframe. Generally, one bit should be sufficient to distinguish between two values ​​of the redundancy version, since it is expected that the number of retransmissions in a multi-subframe configuration will be kept low. Since one RV (redundancy version) bit represents two possible states, it is currently assumed that the first RV state represents RV0 and the second RV state represents RV2. It should be noted that the table in Figure 6 is merely an example of a new DCI format for multi-subframe grants, as it merely summarizes the current state of the study and is still subject to change.

[0066] With the exception of the "Number of scheduled subframes" field, all fields shown in Figure 6 are also applicable to new DCI formats for scheduling resources on unlicensed carriers for one subframe (provisionally referred to as DCI Format 0A and DCI Format 4B, which generally correspond to DCI Format 0 and DCI Format 4, respectively). Since resources are allocated for only one subframe, some fields marked "per subframe" in Figure 6 are only applicable to the subframes shown.

[0067] Regarding multi-layer transmission, previous releases of LTE provided various mechanisms for disabling codewords. As mentioned above, up to four layers are currently supported in the LTE uplink. In a two (or more than two) layer transmission configuration, one codeword can be dynamically disabled by a specific combination of DCI fields that are rarely used, especially in combination with two-layer transmission. In particular, in Release 8, it is possible to disable a codeword in the downlink (there is no MIMO in this release in the uplink) by using DCI Format 2 and DCI Format 2A (plus Format 2B, Format 2C, and Format 2D introduced in later LTE releases). MCS =0) and verbosity version is equal to 1 (rv idx =1), the codeword is disabled. In this case, we assume that the QPSK modulation scheme, as the most robust modulation scheme available, provides sufficient quality so that in most cases not all possible redundancy versions are needed. The redundancy version with value 1 is the last redundancy version in the order of applied redundancy versions: 0, 2, 3, 1.

[0068] In Release 13, two further possible ways to disable codewords were defined. Codewords are disabled for certain combinations of MCS index and number of physical resource blocks (PRBs) in DCI format 4. Specifically, in DCI format 4, when the MCS index is equal to 0 (I MCS =0), while the number of PRBs is 2 or more (N PRB >1), the codeword is disabled. Furthermore, if the MCS index is equal to 28 (I MCS =28), and the number of PRBs is equal to 1 (N PRB=1), the codeword is disabled. These combinations were selected by taking into account the power limitations in the uplink. If the smallest MCS is used, it means that the channel conditions are not particularly good. With only one PRB, higher power can be applied to ensure successful transmission. However, as the number of PRBs increases, the power is spread and the probability of correct reception decreases. Therefore, when multi-layer transmission is applied, the smallest MCS index is unlikely to be used with a large number of PRBs. On the other hand, with the largest MCS index that defines the MCS, the channel quality is likely to be extremely high. Therefore, it is unlikely that only one PRB will be configured in such a high channel quality case.

[0069] Codeword nulling is primarily useful when increased coverage or robust retransmissions are desired. The UE can employ beamforming for single-codeword transmissions to increase overall coverage. Beamforming for single-codeword transmissions can also improve the SINR and therefore achieve higher uplink throughput compared to non-beamformed single-antenna port transmissions.

[0070] Furthermore, if only one codeword in a previous multi-codeword transmission needs to be retransmitted, it may be advantageous to nullify the second codeword in order to reduce interference between the codewords.

[0071] However, when applying a multi-subframe grant, these existing solutions may no longer be adequate. In particular, using only MCS values ​​equal to 0 may limit the coverage of the corresponding PUSCH transmission, while using only MCS equal to 28 may limit the throughput of the PUSCH transmission indicated by the multi-subframe (MSF) grant.

[0072] Considering that only one redundancy version is currently considered for each subframe (see Figure 6), using the redundancy version index as a condition may not be appropriate either. Furthermore, the redundancy version is common to both codewords in that subframe. Furthermore, using the number of allocated PRBs as a condition may not be appropriate either, since the resource block allocation is common to all subframes in both codewords. In addition, the minimum resource allocation for transmission granted on unlicensed carriers is currently 10 PRBs.

[0073] To overcome these problems, the present disclosure provides efficient signaling for disabling codewords with multi-subframe DCI in a multi-layer setting.

[0074] [Disabled by MCS level] In uplink LAA (unlicensed bandwidth), the minimum resource allocation is 10 PRBs. In general, the minimum resource allocation can be a set multiple of the smallest allocable unit in the system (PRB in LTE). Therefore, the enabling / disabling of one or more codewords can be indicated by a specific MCS field value in combination with a condition on the number of PRBs to be allocated. Such exemplary conditions for disabling are as follows: - A minimum MCS index (e.g., MCS=0, the MCS that indicates the most robust modulation and coding rate) and a number of PRBs to be allocated that is greater than a predefined or preconfigured minimum number of allocable PRBs (e.g., in the case of LAA, allocating a number of PRBs greater than 10). - The maximum MCS index (e.g., MCS=28, the MCS that exhibits the lowest robust modulation and coding rate) and the number of PRBs to be allocated equal to the predefined or preconfigured minimum number of allocatable PRBs (e.g., allocate 10 PRBs in the case of LAA).

[0075] For example, in LAA using single-subframe allocation (DCI Format 4A), the above nullification conditions can be adopted to nullify codewords. In DCI Format 4A, the minimum allocation is also 10 PRBs. These conditions can be adapted to multi-subframe allocation (DCI Format 4B), such that the combination of the smallest MCS index and allocating more PRBs than the predefined or pre-configured minimum allocable unit dictates that one codeword is disabled in each subframe scheduled by that DCI, and / or the combination of the largest MCS index and allocating PRBs of the predefined or pre-configured minimum allocable unit dictates that one codeword is disabled in each subframe scheduled by that DCI.

[0076] According to one embodiment, one or more of the MCS levels conventionally assigned to indicate redundancy versions other than 0 are used to signal that a codeword is disabled. For example, in LTE, the MCS levels used to indicate redundancy versions other than 0 are I MCS =29,30,31.

[0077] However, it should be noted that the present disclosure is not limited to LTE / LTE-A systems or future developments thereof. In this embodiment, the disablement of a codeword is signaled by reusing a field for signaling the modulation and coding scheme, which typically has some values ​​used for purposes other than indicating the modulation and coding scheme, and reinterpreting those values ​​for another purpose.

[0078] Exemplary control information in this embodiment includes a resource grant for multiple subframes and multiple codewords in each subframe, and a modulation and coding scheme (MCS) indicator common to the granted subframes and specific to each of the multiple codewords. The MCS indicator can take one of multiple values, including a value indicating one of the multiple MCSs and at least one value indicating no MCS. An MCS indicator for at least one of the multiple codewords with a value indicating no MCS signals disabling of the codeword.

[0079] For example, in the case of two transmission layers, the control information includes two MCS fields (MCS1, MCS2) for two respective codewords. The MCS table can be maintained the same as in the current LTE standard (see FIG. 5), and the control information can correspond to dedicated control information (DCI) having a format used for multi-subframe grants (such as DCI format 4B described above). If one of the codewords is disabled in all granted subframes, the corresponding MCS field is set to one of the redundancy version values ​​29, 30, or 31. For example, if the MCS1 indicator has a value in the range of 0 to 28, while the MCS2 indicator has a value in the range of 29 to 31, the first codeword CW0 is transmitted and the second codeword CW1 is disabled. Conversely, if the MCS1 indicator has a value in the range of 29 to 31, while the MCS2 indicator has a value in the range of 0 to 28, the first codeword CW0 is disabled and the second codeword CW1 is transmitted.

[0080] However, other configurations are possible. For example, there may be one specific value of the MCS indicator that does not indicate an MCS, which disables a codeword. For example, only the value 31 in the above example can be used to disable the corresponding first or second codeword. The remaining values, such as 29 and 30, can be used for other purposes (such as signaling the redundancy version or any other parameter). It is advantageous to choose the value 29 (i.e., the value associated with the least frequently used redundancy version (RV1) in retransmissions) because the remaining values ​​30 and 31 can still be used to indicate redundancy version 2 and redundancy version 3, respectively, as originally intended in the communication system.

[0081] One advantage of the signaling mentioned above is that it supports single-layer beamforming in multi-subframe grants. Also, by reusing only some signaling points of the MCS that are part of the control information, no extra signaling bits are required to disable codewords. This provides an efficient way to disable codewords while still allowing the most important link adaptation.

[0082] However, the present disclosure is not limited by the above example in which codeword disabling is indicated only by a specific value of the MCS indicator. For example, to support subframe-based codeword disabling, a different redundancy version (RV) field can be used for each subframe in addition to the MCS level. The redundancy version field can be included in the control information, for example, as shown in Figure 6 described above, where the redundancy version field in DCI format 4B is common to both codewords but separate (individual) for each subframe and has a length of 1 bit.

[0083] In particular, the value of a specific MCS indicator (field) and the value of a subframe-specific RV field can work together to indicate the codewords to be enabled / disabled and the redundancy version to be applied.

[0084] For example, if MCS1 has a value in the range 0-28 and MCS2 has a value of 29, then if a first RV state (of two states that can be distinguished by one bit, e.g., bit value 0) is indicated, then codeword 1 is disabled. Codeword 0 employs MCS1 and RV2, i.e., retransmissions are performed assuming that the previous transmission was made using RV0. On the other hand, if a second RV state (e.g., bit value 1) is indicated, then codeword 1 is not disabled. Both codewords CW0 and CW1 are transmitted using MCS1 and RV2, i.e., retransmissions are performed assuming that the previous transmission was made using RV0.

[0085] If MCS1 has a value in the range 0-28 and MCS2 has a value of 30, then if a first RV state is indicated, codeword 0 is disabled. Codeword 1 (CW1) uses MCS1 and RV0 (as either an initial transmission or a retransmission depending on the value of the new data indicator (NDI)). In contrast, if a second RV state is indicated, codeword 1 is disabled, while codeword 0 uses MCS1 and RV0 (either a retransmission or a new data transmission, also depending on the NDI value).

[0086] Furthermore, if MCS1 has a value in the range 0-28 and MCS2 has the value 31, then if a first RV state is indicated, codeword 0 is disabled and codeword 1 employs MCS1 and RV2, i.e., the retransmission is performed assuming that the previous transmission employed a redundancy version equal to 0 (RV0). On the other hand, if a second RV state is indicated, codeword 1 is disabled, while codeword 0 uses MCS1 and RV2.

[0087] It should be noted that the above example does not limit the present disclosure. The above example merely describes how the disabling or enabling of codewords can be signaled on a subframe-by-subframe basis by interpreting a combination of the value of the MCS indicator and the value of the redundancy version field without including an additional field in the control information. Generally, in the case of two codewords, one MCS indicator (of the two MCS indicators corresponding to each of the two codewords) indicates the MCS of the enabled codeword. The other MCS indicator takes a value that does not indicate the MCS, but indicates, together with the value of the redundancy version field, which of the two codewords is disabled or that neither codeword is disabled and which redundancy version is applied to the enabled codeword.

[0088] Further embodiments are possible, where MCS1 takes values ​​between 29 and 31 and MCS2 takes values ​​between 0 and 28. For example, such a combination can signal that further redundancy version values ​​are to be applied.

[0089] In the above example, one advantage is that the MCS table currently defined in LTE can be reused. The MCS indicator therefore remains 5 bits long, representing 32 possible MCS values. In legacy uplink grants, these values ​​are used to indicate the MCS (values ​​0-28) and non-zero redundancy versions (values ​​29-31). In uplink multi-subframe grants, these values ​​can be used to indicate the MCS (values ​​0-28) and codeword enable / disable (values ​​29-31). Note, however, that these do not limit the present disclosure. In general, there may be more than two layers and therefore more than two codewords. The MCS can therefore indicate which codewords are disabled in all subframes or on a subframe-by-subframe basis (possibly using a combination of several MCS indicator values ​​and RV field values, as shown above for two codewords).

[0090] Furthermore, in the above example, we reused the legacy MCS table by adopting all MCS values ​​(0-28) for the purpose of signaling MCS. Only the special values ​​29-31, which are used in the legacy system to signal redundancy versions other than 0, were reinterpreted for the purpose of indicating codeword disablement. However, the present disclosure is not limited by such MCS value mapping. For example, some additional values ​​of the MCS indicator can be used to indicate codeword enablement / disablement.

[0091] It should be noted that this embodiment (using one or more MCS field levels that do not indicate an MCS to signal that a codeword is disabled) is generally not limited to multiple subframe allocations. For example, this embodiment (and any of the above-mentioned examples, except for the subframe-by-subframe solution, which is not applicable to single-subframe grants) can be employed in LAA using single-subframe allocations (DCI format 4A). In this embodiment, it is advantageous for the control information to also include precoding indication information that is common to multiple subframes (to which the grant conveyed by the control information applies). This precoding indication information can be a field in the control information that corresponds to a field in legacy DCI format 4.

[0092] [TPMI decision] For multi-subframe scheduling that supports multi-layer transmission, it is advantageous to include a precoding information field as described above. For single-subframe scheduling, the precoding information is currently signaled in a precoding information field that indicates the transmit precoding matrix index (TPMI) together with the number of transmission layers.

[0093] The precoding information field in DCI format 4 for use with two antenna ports has 3 bits and can signal 8 combinations of TPMI and number of layers, which are assigned to 8 different values. The precoding information field in DCI format 4 for use with four antenna ports has 6 bits, and therefore 64 different values ​​of TPMI and number of layers are possible. This is currently specified in Table 5.3.3.1.8-1 of 3GPP TS 36.2.1 (freely available on the 3GPP website and incorporated herein by reference).

[0094] Figure 7 shows the values ​​of the precoding information field and the corresponding meanings of these values ​​for two antenna ports (Figure 7A) and four antenna ports (Figure 7B). These tables correspond to Tables 5.3.3.1.8-2 and 5.3.3.1.8-3 in Non-Patent Document 4, respectively. Specifically, Figure 7A shows two tables (one for the first two columns and the other for the next two columns), which are for one enabled codeword and two enabled codewords, respectively. The first and third columns show the values ​​of the precoding information bit field included in the DCI. The second and fourth columns specify the corresponding associated combinations of the number of layers and TPMI. When one codeword is enabled, six different values ​​of TPMI can be selected, corresponding to indexes 0 to 5 in the precoding information field. Indexes 6 and 7 are reserved. When both codewords are enabled, currently only one TPMI corresponding to index 0 is supported, while indexes 1 to 7 are reserved.

[0095] In Figure 7B, when one codeword is enabled, entries 0 to 39 indicate the combination of the number of layers (which is 1 or 2) and the TPMI (which can take values ​​0 to 23). Values ​​40 to 63 in the precoding information field are reserved. In contrast, when both codewords are enabled, values ​​0 to 28 in the precoding information field indicate the combination of the number of layers (which can take values ​​2 to 4) and the TPMI (which can take values ​​0 to 15). Values ​​29 to 63 are reserved.

[0096] The TPMI for two antenna ports indicates which codebook index is used in Table 5.3.3A.2-1 of Non-Patent Document 1, and the TPMI for four antenna ports indicates which codebook index is used in Tables 5.3.3A.2-2, 5.3.3A.2-3, 5.3.3A.2-4, and 5.3.3A.2-5 of Non-Patent Document 1. A codebook index is associated with a specific precoding matrix.

[0097] In order to keep the overhead cost of the signaling information as small as possible while at the same time maintaining the new DCI (4B) similar to the legacy DCI (4), it is advantageous to keep the same length of the precoding information field. This is particularly advantageous when the channel conditions are not expected to change or when information about changing channel conditions is not available. In contrast, it may be advantageous to provide the number of layers and TPMI for individual subframes for finer control of the transmission parameters, which is particularly advantageous when different channel conditions can be expected throughout the scheduling period.

[0098] As explained above, it is possible to enable / disable one codeword per subframe, so it is desirable to signal precoding information for at least two different cases (one codeword is enabled or both codewords are enabled).

[0099] According to a first example, a second precoding information field may be provided, which indicates the number of layers and TPMI for a subframe in which only one codeword is enabled (assuming that the first precoding information field for when both codewords are enabled is also included in the DCI). The second field may indicate the number of layers and TPMI in the same manner as shown in FIG. 7. In other words, a DCI including a multi-subframe grant may indicate, on a subframe-by-subframe basis, whether one codeword or two codewords are enabled. Therefore, two precoding information fields may be provided: a first precoding information field indicating the number of layers and TPMI for when both codewords are enabled, and a second precoding information field indicating the number of layers and TPMI for when only one codeword is enabled. These two precoding information fields may be defined in the same manner as shown in FIG. 7.

[0100] However, instead, a limited number of bits can be used to dynamically select between pre-defined combinations in order to reduce the signaling data requirements, where the term "limited" means that the number of combinations is smaller than the number of combinations specified for precoding information in the case of scheduling according to DCI format 4 (e.g. in a licensed carrier).

[0101] Referring illustratively to the left portion of the table in Figure 7B, the number of selectable TPMIs for each number of transmission layers is sub-sampled to reduce the total number of choices. For example, instead of allowing all TPMI values ​​0 through 23 to be selected for a one-layer transmission, only the even TPMI values ​​0, 2, 4, ..., 22 are available (or alternatively, only the odd TPMI values ​​1, 3, 5, ..., 23 are available). Similarly, for a two-layer transmission, only the even TPMI values ​​0, 2, 4, ..., 14 are available (or alternatively, only the odd TPMI values ​​1, 3, 5, ..., 15 are available). In this way, a total of 20 values ​​are available, and the 20 values ​​can be signaled by a 5-bit field (instead of 6 bits to select all 40 values).

[0102] The subsampling does not have to be in a regular pattern (every other value, every third value, etc.), because a regular pattern would generally not fully utilize the capacity of the bit field signal. That is, as just described, subsampling by a factor of 2 requires a field size of 5 bits, but this subsampling utilizes only 20 of the 32 possible states. Utilizing all 32 states can be achieved, for example, by selecting 16 TPMI values ​​(out of the 24 defined TPMI values) for layer 1 transmission and retaining the 16 TPMI values ​​for layer 2 transmission. Such uneven subsampling is advantageous for supporting more optimized layer 2 transmission. An alternative is to retain the 24 TPMI values ​​for layer 1 transmission and select 8 TPMI values ​​(out of the 16 defined TPMI values) for layer 2 transmission. The latter can be easily achieved by subsampling the 16 values ​​by a factor of 2 (e.g., selecting only even TPMIs or only odd TPMIs). In this way, all TPMI options for layer 1 transmission are reserved, which is advantageous for achieving optimal SINR in extended coverage of the uplink signal. Similarly, if only 3 bits are to be used in the second precoding information field, for example, the total number of 40 different combinations of the number of layers and TPMIs needs to be subsampled to 8 combinations. This can be achieved by subsampling the 24 TPMIs defined for layer 1 by a factor of 3 and not including any TPMIs for layer 2.

[0103] One further advantage of including a second precoding information field applicable to subframes in which one codeword is enabled and one codeword is disabled is that the size of the first precoding information field can be reduced. Since the first precoding information field only needs to cover the case in which two codewords are enabled, in the case of four antenna ports, it only needs to represent states 0 to 28. These 29 states can be represented by 5 bits, thus saving 1 bit compared to the size of the precoding information field in DCI format 4 for four antenna ports. In the case of two antenna ports, including the first precoding information field in the DCI is even unnecessary; in other words, a size of 0 bit is sufficient for this field, since only the combination of two layers and TPMI is defined.

[0104] This method can also be extended to the case where more than two codewords per subframe are supported, in which case a first Precoding Information field applicable to subframes in which no codewords are disabled is provided, a second Precoding Information field applicable to subframes in which a first non-zero number of codewords are disabled is provided, a third Precoding Information field applicable to subframes in which a second non-zero number of codewords are disabled is provided, etc. In other words, the number of Precoding Information fields will generally be capped at, and preferably equal to, the maximum number of codewords that may be enabled in a subframe.

[0105] According to a second example, the precoding information for one codeword is semi-statically configured (e.g., by the Radio Resource Control Protocol (RRC)). In other words, the precoding information for both codewords (see the right side of Figures 7A and 7B) is included in the DCI conveying the multi-subframe grant, and the precoding information for when only one codeword is enabled is signaled by the RRC. The TPMI for two codewords primarily aims to minimize interference between the two codewords, while the TPMI for one codeword primarily aims to improve the SINR through beamforming. In many scenarios, the optimal beam direction for beamforming corresponds to the line of sight between the transmitter and receiver, which is relatively stable for terminals that do not move much. Conversely, the optimal precoder for minimizing inter-symbol interference in many scenarios attempts to eliminate correlation between channels as much as possible, which is more dependent on obstacles in the radio wave propagation environment and therefore can be expected to be more variable. For these reasons, it is most efficient for the precoding information for one enabled codeword to follow semi-static RRC signaling, while the precoding information for two enabled codewords is preferably indicated in the DCI (and can therefore be adapted relatively quickly to changing channel conditions).

[0106] Alternatively, the precoding information for two enabled codewords can be configured by semi-static signaling, and the precoding information for one enabled codeword is included in the DCI format. This method is particularly applicable when the number of layers and the number of available TPMI options are significantly greater for one codeword than for two codewords. For example, referring to FIG. 7A, there is only one valid entry for two codewords. From this perspective, it is even possible to operate without a corresponding precoding information field in the DCI. Conversely, for one codeword, there are six different options, and therefore, it can be expected that the optimal selection of the TPMI may differ even if the channel conditions change slightly.

[0107] The semi-static signaling may be conveyed by terminal-specific RRC messages when establishing a radio access bearer or at any subsequent time when reconfiguring a radio access bearer.

[0108] This example and alternative examples can be extended to the case of more than two codewords per subframe, in which case the precoding information for the first number of disabled codewords and the second number of disabled codewords is each conveyed by semi-static configuration, and the precoding information for the third number of disabled codewords is conveyed by DCI. Alternatively, the precoding information for the first number of disabled codewords and the second number of disabled codewords is each conveyed by DCI, and the precoding information for the third number of disabled codewords is conveyed by semi-static configuration.

[0109] According to a third example, candidates for precoding information for one codeword are semi-statically configured. Furthermore, a specific selection of precoding information among the semi-statically configured candidates is dynamically signaled, for example, by using several values ​​of MCS and / or RV. For example, MCS values ​​29, 30, and 31 can be used to indicate the selection of the first, second, and third candidates, respectively. The first, second, and third candidates can be configured by RRC by assigning specific combinations to these candidates, such as those defined in the table of FIG. 7.

[0110] In another example specific to the third example, MCS values ​​29, 30, and 31 may be used with a first RV value to indicate selection of the first, second, and third candidates, respectively, while MCS values ​​29, 30, and 31 may be used with a second RV value to indicate selection of the fourth, fifth, and sixth candidates, respectively. Candidates 1 through 6 may be configured by the RRC by assigning specific combinations to these candidates, such as those defined in the table of FIG. 7.

[0111] This third example can be extended to cases where more than two codewords are supported and at least one codeword is disabled. The number (and index) of disabled codewords can be determined by determining whether the corresponding MCS field contains values ​​from 0 to 28 (i.e., assigning a modulation and coding scheme) or values ​​from 29 to 31. This adds another dimension to the number of layers and the number of semi-statically preconfigured precoding options. For example, if three codewords and three corresponding MCS fields are supported, the cases where one codeword is enabled and two codewords are disabled are characterized by a first MCS field with values ​​from 0 to 28 and second and third MCS fields with values ​​from 29 to 31, respectively. Thus, the two MCS fields, each representing 29 to 31, work together to provide nine different options, which can be used to represent nine different combinations of the number of transmission layers and TPMI. The number of configurable combinations can be further increased by using an RV field in addition to this.

[0112] According to a fourth example, only one precoding information field is included in the DCI to signal precoding information for both two enabled codewords and one enabled codeword. This precoding information field is similar to the precoding information field used in DCI Format 4 for two codewords in legacy systems, i.e., for four antenna ports, it has 6 bits and 29 possible values, with the remaining values ​​being reserved. Values ​​0 to 28 represent indexes of combinations of layer number and TPMI value. Values ​​29 to 63 are reserved. In this example, the reserved values ​​are used to convey individual candidates for only one enabled codeword. Thus, in the case of two-codeword transmission with both enabled codewords, values ​​0 to 28 indicate the same combinations of TPMI and layer number as used by DCI Format 4. When only one codeword is enabled, values ​​29 to 56 indicate the combinations (TPMI and layer number) for the one enabled codeword. The combinations associated with values ​​0 to 28 may be the same as the combinations associated with values ​​29 to 56, respectively. The remaining values ​​57-63 can be used for other purposes, or alternatively, to provide a larger number of selectable combinations.

[0113] In the following, we refer to the value indicated by the precoding information field as I L,TPMI A specific example for determining the number of layers and TPMI according to this fourth example is presented. In the case of four antenna ports, for two enabled codewords, the number of layers and TPMI are determined by searching for "I" in the "Bit field mapped to index" column according to the table in FIG. 7B. L,TPMI mod 29. Therefore, I L,TPMI =0 and I L,TPMI =29 indicates that the assigned transmission uses two layers and TPMI=0. L,TPMI =17 and I L,TPMI=46 indicates that the assigned transmission uses 3 layers and TPMI=1. For a subframe with one codeword enabled and one codeword disabled, I L,TPMI ={0-28} indicates that the first combination of TPMI and layer number is used in the assigned transmission, while I L,TPMI ={29-56} indicates that the second combination of TPMI and number of layers is used in the assigned transmission. The first and second combinations (and other combinations, if applicable) are preferably selected from the set of combinations available for one disabled codeword in the case of single-subframe scheduling, e.g., from the set of combinations in the left part ("Message") of the table in Fig. 7B. This selection is preferably predefined through a fixed specification, or configurable by semi-static signaling, allowing the selection of the combination that is best suited for specific channel conditions for each terminal and at the right time.

[0114] In the specific example of two antenna ports, for two enabled codewords, the number of layers and TPMI are determined by searching for "I" in the "Bitfields mapped to index" column according to the table in FIG. 7A. L,TPMI mod 1. Therefore, I L,TPMI ={0,1,2,3,4,5,6,7} all indicate that the assigned transmission uses 2 layers and TPMI=0 (this is obviously trivial since this is a special case where only one type of layer number and TPMI is defined). For a subframe where one codeword is enabled and one codeword is disabled, I L,TPMI ={0} indicates that the first combination of TPMI and layer number is used in the assigned transmission, while I L,TPMI={2} indicates that the second combination of TPMI and layer number is used in the assigned transmission, and so on. The first combination, the second combination, and another combination (if applicable) are preferably selected from the set of combinations available for one disabled codeword in the case of single-subframe scheduling, e.g., selected from the set of combinations in the left part ("Message") of the table in FIG. 7A. This selection is preferably predefined through a fixed specification, or configurable by semi-static signaling so that the combination that is optimal for specific channel conditions can be selected for each terminal and in accordance with the timing. In this particular example, a total of six combinations are defined for one enabled codeword, and the precoding information field can represent more than six combinations (eight in this particular example), and thus can indicate all six defined combinations without needing to be semi-statically configurable.

[0115] According to a fifth example, the DCI signaling a multi-subframe allocation does not include a second precoding information field. The number of layers and precoding information when two codewords are enabled in a subframe are determined according to the precoding information field included in DCI format 4B (for multi-subframe allocation). The number of layers and precoding information when one codeword is enabled in a subframe are determined from the precoding information in the most recently signaled DCI format 4A (for single-subframe allocation). This example assumes that the channel conditions, and therefore the appropriate combination of TPMI and number of layers, do not change substantially over time (which is reasonable to assume, at least for terminals that are not very mobile).

[0116] According to the sixth example, a fixed mapping is introduced between the combination of precoding information signaled for both enabled codewords and the applicable combination for one enabled codeword. In other words, the multi-subframe DCI (Format 4B) includes one precoding information field, similar to DCI Format 4. This precoding indication information signals the combination of TPMI and layer number for two enabled codewords. Therefore, subframes in which both codewords are enabled use this signaled combination. Subframes in which only one of the two codewords is enabled apply the combination determined according to the fixed mapping of the combination signaled for both enabled codewords to the applicable combination for one enabled codeword.

[0117] In the examples above, codewords can be disabled or enabled on a subframe-by-subframe basis. Furthermore, precoding information can be signaled separately for different numbers of enabled codewords, which is advantageous. The examples above are presented in conjunction with an existing LTE system. However, it should be noted that the present disclosure is not limited to LTE, or to a maximum of two codewords, or to precoding information signaled as shown in FIG. 7 . Instead, the present invention is applicable to any system using multi-subframe allocation with MIMO with precoding that allows for the mapping of more than one codeword to one subframe. In such systems, one or more codewords can be disabled on a subframe-by-subframe basis by using a modulation and coding scheme indicator value that is not associated with a specific MCS, possibly in combination with a specific value of another signaled parameter such as the redundancy version. Correspondingly, precoding information for each such configuration (e.g., one codeword disabled, two codewords disabled, three codewords disabled, etc.) can be signaled. Such signaling can be provided, according to the examples described above, for example, by explicitly including a precoding information field for each configuration in the DCI, or by semi-statically configuring the precoding information for each such configuration, or by a combination of inclusion in the DCI and semi-static signaling, or by reusing reserved fields.

[0118] Alternatively, the precoding information field conveys information on whether one codeword is disabled or two codewords are enabled. This alternative method is applicable to multi-subframe scheduling as well as single-subframe scheduling, where the enabling or disabling of a codeword applies to all subframes scheduled by the corresponding DCI. A first set of precoding information values ​​implies that one codeword is disabled, and a second set of precoding information values ​​implies that two codewords are enabled. For example, in the case of two antenna ports, referring to FIG. 7A, the first set consists of six values ​​and corresponding interpretations shown in the two left columns, and the second set consists of one value and corresponding interpretation in the two right columns. Thus, there are a total of seven values, i.e., the 3-bit size of the precoding information field can be maintained. The values ​​indicated by the precoding information field can be expressed as I, II, III, IV ... L,TPMI When expressing, the following method can be used: 0≦I L,TPMI If ≦5: Codeword 0 is enabled and codeword 1 is disabled. The number of layers and TPMI are expressed as I L,TPMI Request according to. I L,TPMI If =6: Codeword 0 is enabled and codeword 1 is enabled. The number of layers and TPMI are expressed as I L,TPMI -6.

[0119] For example, in the case of four antenna ports, referring to FIG. 7B, the first set consists of 40 values ​​and corresponding interpretations shown in the two left columns, and the second set consists of 29 values ​​and corresponding interpretations in the two right columns. Therefore, there are 69 values ​​in total, i.e., the size of the precoding information field is 7 bits. The values ​​indicated by the precoding information field are called I L,TPMIWhen expressing, the following method can be used: 0≦I L,TPMI If ≦39: Codeword 0 is enabled and codeword 1 is disabled. The number of layers and TPMI are expressed as I L,TPMI Request according to. 40≦I L,TPMI If ≦68: Codeword 0 is enabled, and codeword 1 is enabled. The number of layers and TPMI are shown in the two right columns as I L,TPMI Calculate according to -40.

[0120] In this way, the set can be reduced (subsampled) to achieve a smaller number of bits in the precoding information field. For example, considering the above case of four antenna ports, it may be desirable to maintain the number of 6 bits in the precoding information field for commonality in the system. With 6 bits, a set size of 64 combinations is supported, i.e., compared to the full set of combinations, 69 - 64 = 5 combinations need to be removed. Such subsampling can be applied, for example, as described above in connection with the first example.

[0121] The present disclosure further provides an apparatus 810 for receiving resource grants for multiple subframes in a communication system 800. Such an apparatus can be any type of mobile station (user equipment: UE), such as a mobile phone, a smartphone, a USB adapter, a computer, a tablet, a laptop, or a wearable device (e.g., a smart watch or smart glasses). Advantageously, the communication system is an LTE or LTE-A system. However, the present invention is not limited to an LTE system. Instead, any 4G or 5G system, or even any system employing multiple antennas and corresponding signaling, such as WiFi, WiMax, etc., can be utilized.

[0122] The apparatus includes a transceiver 820 that receives a signal 855 containing control information. The transceiver may be, for example, a transceiver capable of receiving and transmitting LTE / LTE-A compatible signals. Figure 9 illustrates possible uplink transmission processes (Figure 9A) and downlink transmission processes (Figure 9B) in LTE. However, it should be noted that these are merely examples. The transceiver 820 typically includes one or more antennas and corresponding circuitry for controlling the gain of the antennas, as well as mappers for user data, control data, and reference signals to physical resources.

[0123] The control information included in the signal 855 includes resource grants for multiple subframes and multiple codewords in each subframe. The resource allocation may indicate the location of the transmission resources in the time domain and / or the frequency domain. The number of subframes for which the resource allocation is valid may also be signaled in the control information, as illustrated in FIG. 6. However, it should be noted that the present disclosure is not limited thereto, and the number of subframes may be pre-configured or pre-defined in other ways (e.g., semi-statically). The multiple codewords may be two or more codewords, some of which may be disabled.

[0124] The control information further includes a modulation and coding scheme (MCS) indicator that is common to the allocated subframes and specific to each of the allocated codewords. The MCS indicator takes one of multiple values, including a value indicating one of multiple MCSs and at least one value that does not indicate an MCS. The MCS indicator can be a field with a predefined bit length capable of representing a range of values. Some of the values ​​are associated with a specific modulation (more specifically, a modulation order if the modulation type is the same) and the size of the transport block(s) mapped to the allocated resources (determined by the applied coding). Some of the values ​​are not associated with coding or modulation. The latter values ​​can be used for other purposes or reserved. In the above UL LTE example, values ​​29 to 31 are used to signal redundancy versions.

[0125] When the control information is received by the transceiver 82 as part of the signal 855, a processing device 830, which is part of the apparatus 810, further processes the control information. In particular, the processor 830 is configured to determine that a codeword from a plurality of codewords in a plurality of subframes is to be disabled if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate MCS, and is not disabled otherwise. This does not necessarily mean that an MCS indicator that does not indicate MCS always implies disabling. In one embodiment, an MCS indicator that does not indicate MCS always implies disabling. In another embodiment, an MCS indicator that does not indicate MCS can indicate disabling only in combination with another parameter value, as will be shown later.

[0126] The processing device 830 may be one processor or multiple processors. The processing device 830 may be an integrated circuit, programmable hardware, or a combination of such devices. Such a processing device 830 may extract control information from a signal received by the transceiver 820 and further extract a specific field of the control information that conveys a setting value. As described above, in a current LTE system or an LTE-A system, the signal 855 may correspond to a downlink signal transmitted from an eNB to a terminal, the control information may correspond to DCI, the MCS indicator may correspond to an MCS field, and the precoding information may correspond to a combination of TPMI and the number of layers.

[0127] In one embodiment, the plurality of values ​​includes 32 values ​​indexed according to the PUSCH MCS table applied in LTE. Of these values, the three values ​​with the highest indexes do not indicate an MCS and can be used to indicate the deactivation of codewords for multiple subframes. In particular, the 32 values ​​can be provided by all combinations of 5 bits, such that the MCS indicator is 5 bits long (i.e., a 5-bit field is included in the DCI). Furthermore, of the 32 values, a predefined or preconfigured number of values ​​can be associated with a specific MCS (29 in LTE, i.e., values ​​0 to 28), while the remaining values ​​are not associated with a specific MCS (3 in LTE, i.e., values ​​29 to 31). The value 32 is advantageous because it allows the reuse of MCS tables already defined in LTE. However, the present invention is not limited by this example, and the number of values ​​may be larger or smaller depending on the number of bits provided for MCS signaling in the control information. An advantage of this method in the LTE example is that the number of configurable MCSs is not further reduced, but rather values ​​indicating redundancy versions are utilized. If the RV is signaled separately for each subframe as illustrated in FIG. 6, the RV value is no longer needed.

[0128] In other words, legacy terminals can use the MCS table to indicate MCS and / or RV, while terminals configured to support multi-subframe allocation can use (interpret) the same MCS table to indicate MCS and to indicate codeword disablement in the same way as legacy terminals.

[0129] Advantageously, the control information further comprises redundancy version indication information that is individual for each of the plurality of subframes and common to all codewords in the respective subframe. In this case, the processing device is configured to determine that a codeword from the plurality of codewords in the plurality of subframes is to be disabled if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS and the redundancy version indication information has a first predefined value. Otherwise, i.e., if the MCS indicator takes a value that indicates a specific MCS from a plurality of configurable MCSs and is combined with another value of the redundancy version indication information that is signaled per subframe and indicates one of the configurable redundancy versions, the codeword or codewords are not disabled. As will be apparent to those skilled in the art, in the above example specific to LTE, the length of the redundancy version indicator for a subframe in the multi-subframe DCI was 1 bit (indicating a selection between RV=0 and RV=2, which are the two most important RVs in terms of performance), but this does not limit the present disclosure. The redundancy version may be 2 bits long, indicating an RV of 0 to 3, as in the legacy DCI, or may be any other length for systems requiring more redundancy versions.

[0130] As explained above, in a subframe in which one codeword is enabled and one codeword is disabled, the processing device is advantageously configured to determine the redundancy version of the enabled codeword based on a specific value that does not indicate the MCS (used together with the redundancy version indication information to indicate the disablement of the disabled codeword). In other words, the MCS indicator and the RV indicator (both included in the control information) jointly indicate the disablement or enablement of a codeword and the RV of that codeword.

[0131] In a subframe in which two codewords are enabled and none of the codewords are disabled, the processing device may be configured to determine the MCS of the enabled codewords based on a particular value indicating the MCS, such as values ​​0-28 in the above example related to LTE, which is not used to indicate the disabling of the disabled codewords (possibly together with redundancy version indication information).

[0132] The control information may further include a precoding information field common to multiple subframes for which the control information indicates an allocation (grant). The precoding indication information field may indicate a TPMI and / or a layer number. Note that in the above example, the precoding information field indicates the combination of the TPMI and the layer number because a similar precoding information field exists in current LTE. However, the present disclosure is not limited by these examples. Instead, the precoding information field may indicate only the TPMI, and the layer number may generally be signaled by another field, or may be implicitly indicated, or signaled in another layer. Meanwhile, the precoding information may signal additional settings.

[0133] In one embodiment, the precoding information indicates a combination of a transmit precoding matrix indication (TPMI) and the number of transmission layers, which can be done in a variety of different ways.

[0134] For example, in one example, the precoding information may indicate one combination of TPMI and number of transmission layers from among multiple predefined combinations of TPMI and number of transmission layers, which may be predefined in a standard and known to both the receiver and the transmitter.

[0135] In another example, the precoding information may indicate one combination of TPMI and transmission layer number among multiple combinations of TPMI and transmission layer number in a candidate set preconfigured by semi-static signaling. In particular, an RRC message from the base station to the terminal may configure a candidate set of indices associated with each combination of TPMI and layer number. Advantageously, the number of combinations in the candidate set is smaller than all possible combinations and / or all configurable configurations. The candidate set may be selected based on, for example, channel conditions, interference, terminal capabilities, or any other parameters. In this case, the control information conveys a precoding information field with a smaller bit length, allowing signaling of only values ​​in the preconfigured candidate set. For example, if there are 32 generally possible combinations, the precoding information requires five bits to signal them. However, the candidate set may include only four candidate combinations preconfigured by RRC, in which case only two bits are required to select a combination among the candidates in the dynamically signaled precoding information.

[0136] In yet another example, the precoding information indicates one combination of TPMI and number of transmission layers from among multiple predefined combinations of TPMI and number of transmission layers that are selectable even in the case of a single-layer configuration using one codeword per subframe, or from among multiple predefined combinations of TPMI and number of transmission layers that are not selectable in the case of a single-layer configuration, in which case the value of the precoding indication information indicating each combination of TPMI and number of transmission layers that is not selectable in the case of a single-layer system is a reserved value in the precoding indication information for the single-layer configuration.

[0137] In other words, the transceiver is configured to receive radio resource control protocol configuration information including a precoding configuration, and the processing device is further configured to set precoding parameters according to the received precoding configuration.

[0138] 8 also shows an apparatus 850 for transmitting resource grants for multiple subframes in a communication system. This apparatus may be a network node or base station, or a terminal operating as an access point, or any other scheduling entity. In LTE, this apparatus may correspond to an eNB.

[0139] The apparatus 850 includes a processing device 870 configured to set a modulation and coding scheme (MCS) indicator to a value that does not indicate MCS to indicate that a codeword from a plurality of codewords in a plurality of subframes is disabled. For example, the apparatus may be a scheduling entity that selects transmission configurations for another apparatus and provides the selected configurations to the other apparatus via control information. The configurations may include, for example, physical layer parameters such as modulation and coding configurations, MIMO configurations such as the number of layers and precoding matrices, resource allocations, HARQ configurations, etc.

[0140] The apparatus 850 further comprises a transceiver 860 that transmits a signal including control information, the control information including at least a resource grant for a plurality of subframes and a plurality of codewords in each subframe, precoding instruction information common to the plurality of subframes, and an MCS indicator (taking one of a plurality of values ​​including a value indicating one of a plurality of MCSs and at least one value indicating no MCS) common to the plurality of granted subframes and individual to each of the plurality of codewords.

[0141] Processing device 870 may be one or more processors, one or more integrated circuits, programmable hardware, etc., configured or programmed to perform the tasks described above, similar to processing device 830. Note that processing device 870 may further advantageously select the control information and values ​​for each of its fields, as described above in connection with apparatus 810 and the retrieval / processing of the control information by apparatus 810.

[0142] 8, there is also provided a communication system comprising an apparatus 810 for receiving control information and an apparatus 850 for transmitting control information for controlling transmission of data over a channel by the apparatus 810. The channel may be at least partially a wireless channel. The system may be part of a communication system, which may for example be LTE, LTE-A, a further development of LTE (such as LAA), or any other system comprising a wireless link.

[0143] [Disable by dedicated field] According to one embodiment, the activation / deactivation of a codeword is explicitly indicated and is valid for each subframe of the corresponding resource allocation. The control information may include, inter alia, a dedicated codeword activation / deactivation field indicating the activation and / or deactivation of a codeword for each subframe allocated by the resource allocation. The dedicated codeword activation / deactivation field preferably consists of one bit in the control information, where a first bit state (e.g., bit value = 0) indicates that one codeword is activated and one codeword is deactivated, and a second state (e.g., bit value = 1) indicates that two codewords are activated. This activation / deactivation applies in each subframe allocated by the control information, and therefore this embodiment is applicable not only to single-subframe allocations but also to multi-subframe allocations. In other words, the activation / deactivation of a codeword is explicitly indicated in the multi-subframe DCI by including a corresponding activation / deactivation field common to all subframes in the multi-subframe DCI.

[0144] According to another embodiment, the enabling / disabling of codewords is indicated explicitly and separately for each subframe. In particular, the control information may include a dedicated codeword enabling / disabling field that indicates the enabling and / or disabling of codewords for each subframe.

[0145] In one example, a codeword enable / disable bitmap is provided, where each bit represents a subframe and the value of each bit indicates whether a codeword is enabled or disabled in the respective subframe. This can be done by a bit where a bit set to 0 indicates that one codeword is disabled and a bit set to 1 indicates that both codewords are enabled (or vice versa) (if there are only two codewords that can be set).

[0146] In other words, the codeword enable / disable field (bitmap) indicates whether each subframe uses one codeword or two codewords, assuming that there is a maximum number of codewords equal to 2. Thus, the bitmap can have a length of, for example, 2 bits, 3 bits, 4 bits, or 5 bits or more (generally 10 bits or less), depending on the configured number of subframes for which one scheduling message is provided (the number of subframes in the plurality of subframes).

[0147] It should be noted that the present disclosure is not limited to the case where there are only two configurable codewords, as in the LTE example above. A bitmap per subframe and codeword can be provided to indicate the activation / deactivation of a larger number of codewords. In the case of a larger number of codewords, it is assumed that one MCS field for each codeword is included in the DCI.

[0148] In this embodiment, a modulation and coding scheme indicator taking values ​​from 0 to 28 is advantageously applied to select the modulation and coding scheme for both two-codeword transmission (when both codewords are enabled) and one-codeword transmission (when only one codeword is enabled). In other words, if the codeword enable / disable field for a subframe indicates two-codeword transmission, an MCS with index values ​​from 0 to 28 is applied to both codewords in that subframe, and if the codeword enable / disable field for a subframe indicates one-codeword transmission, an MCS with index values ​​from 0 to 28 is applied to one codeword in that subframe.

[0149] The disabling of codewords does not necessarily have to be indicated by a bitmap. Instead, the field indicating whether codewords in a particular subframe are enabled or disabled can indicate the number and / or identity of the disabled codewords. Alternatively, this field can indicate the number and / or identity of the enabled codewords.

[0150] For example, for each subframe, the codeword enable / disable field can represent two states: (1) two codewords are enabled, or (2) one codeword is enabled and one codeword is disabled. In such an example, if only one codeword is enabled, it can be assumed that the first codeword is enabled and the second codeword is disabled. Such a field requires a total of exp(2,n) states for n subframes, which can be represented by an n-bit long field.

[0151] In another example, for each subframe, the codeword enable / disable field can represent three states: (1) two codewords are enabled, (2) codeword 0 is enabled and codeword 1 is disabled, and (3) codeword 0 is disabled and codeword 1 is enabled. Such a field requires a total of exp(3,n) states for n subframes, which can be represented by a field Ceil{log2(exp(3,n))} bits long.

[0152] In another example, for each subframe, the codeword enable / disable field can represent four states: (1) two codewords are enabled, (2) codeword 0 is enabled and codeword 1 is disabled, (3) codeword 0 is disabled and codeword 1 is enabled, and (4) codeword 0 is disabled and codeword 1 is disabled. Such a field requires a total of exp(4,n) states for n subframes, which can be represented by a 2n-bit long field.

[0153] Regarding the precoding information, the options described above can also be applied to this embodiment. In other words, the precoding information can be indicated in the control information by inserting a precoding information field in the control information. The precoding information field can be inserted separately when configuring one codeword transmission and when configuring two codeword transmission. For details on such precoding information, please refer to the above section "Determining TPMI".

[0154] However, the precoding information can be indicated in other ways. For example, one precoding information field can be included in the control information, and this precoding information field indicates the precoding information for a two-layer configuration in which both codewords are enabled. In this case, this precoding information is applied to subframes in which both codewords are enabled. Furthermore, reserved MCS entries 29 to 31 can be used to obtain the precoding configuration for one-codeword transmission, i.e., the configuration for subframes in which only one of the two codewords is enabled (one codeword is disabled).

[0155] In particular, for one codeword transmission, when MCS1 is equal to 29 to 31, there is a choice between three possible configurations (combinations of TPMI and number of layers). When MCS2 is equal to 29 to 31, there is a choice between three additional configurations. Thus, the base station can dynamically select between six precoding configurations for the case of one codeword. The six possible values ​​may also indicate a combination of TPMI and number of layers as described above. However, the present invention is not limited thereto, and the precoding information may convey only precoding matrix indication information. The number of layers may be indicated in another way.

[0156] The allocation of TPMI and layer number combinations to MCS1 and MCS2 is advantageously controlled semi-statically, i.e. MCS1 and MCS2 values ​​29-31 are assigned values ​​from a set of candidates signaled by RRC, in which case dynamic signaling in the control information conveying the grant only selects the combination from a pre-configured set of candidates.

[0157] Note that the above-described configuration of precoding information based on MCS field values ​​that do not indicate MCS is not available only when the enabling / disabling of codewords per subframe is explicitly signaled. Instead, MCS field values ​​that are not used to signal MCS (and even in legacy communications such as one-layer communications without MIMO, or in single-subframe DCI (especially DCI format 4)) can be used to indicate precoding information regardless of how the enabling / disabling of codewords is signaled. Note that, looking at the MCS table in Figure 5, MCS field values ​​29, 30, and 31 can also be defined as values ​​that are not used to signal transport block index or modulation.

[0158] According to this embodiment, an apparatus 810 for receiving a resource grant for a plurality of subframes in a communication system comprises a transceiver 820 for receiving a signal including control information. The control information includes a common resource grant for a plurality of subframes and a plurality of codewords in each subframe, and codeword indication information indicating enabling or disabling of one or more codewords in each of the plurality of subframes. The apparatus 810 further comprises a processing device 830 configured to determine, for each subframe, whether a codeword from the plurality of codewords in that subframe is enabled or disabled in accordance with the codeword indication information.

[0159] The codeword indication information may be, for example, a bitmap including an individual bit for each of a number of subframes, each individual bit indicating whether one codeword or two codewords are enabled.

[0160] However, a bitmap is only one example. Alternatively, the codeword indication information is either an identifier of the codeword to be disabled or an identifier of the codeword to be enabled. In particular, if there are more than two codewords configurable for transmission, it may be advantageous to also include the number of codewords to be disabled or the number of codewords to be enabled in the codeword indication information. In some systems, it may be advantageous to signal only the number of codewords to be disabled or the number of codewords to be enabled, and assume that the disabled codeword is the codeword with the highest index.

[0161] Furthermore, in this embodiment, advantageously, the control information further includes a modulation and coding scheme (MCS) indicator common to the plurality of granted subframes and individual to each of the plurality of codewords, wherein the MCS indicator takes one of a plurality of values ​​including a value indicative of one of the plurality of MCSs and at least one value not indicative of any MCS, while the processing device is further configured to determine the modulation and coding scheme of each enabled codeword according to the MCS indicator taking the value indicative of one of the plurality of MCSs.

[0162] The processing device may be configured to determine the precoding configuration based on an MCS indicator having a value that does not indicate one of the multiple MCSs if a codeword is enabled, or to determine which codewords are disabled based on an MCS indicator having a value that does not indicate one of the multiple MCSs or based on a redundancy version indicator for a subframe in which a codeword is enabled.

[0163] Also in this embodiment, an apparatus 850 for transmitting resource grants for a plurality of subframes in a communication system is provided corresponding to the control information receiving apparatus 810.

[0164] The apparatus 850 comprises a processing device configured to select, for each subframe, whether a codeword from a plurality of codewords in that subframe is enabled or disabled and to set codeword indication information accordingly; and a transceiver to transmit a signal comprising control information including a common resource grant for the plurality of subframes and the plurality of codewords in each subframe, and codeword indication information indicating the enabling or disabling of one or more codewords in each of the plurality of subframes.

[0165] Further features of the control information are the same as those described above in connection with the corresponding control information receiver. The control information transmitter is advantageously a scheduling device such as a base station or a network node (eNB in ​​LTE has both of these functions). The control information transmitter typically not only transmits the control information but also selects the control information parameter values ​​by which the control information receiver is configured.

[0166] FIG. 10 illustrates an exemplary method according to the present disclosure. Specifically, FIG. 10 illustrates a method for receiving resource grants for multiple subframes in a communication system. Such a method may be performed in an apparatus such as a user equipment (UE) as illustrated in the figure. The method includes receiving 1020 a signal including control information. The control information may be downlink control information (DCI). For purposes of the present invention, the manner in which the DCI is received is not important. Reception of the DCI may be by monitoring a PDCCH (including blind decoding), as in LTE, but may also be performed in a scheduled manner or in any other manner.

[0167] The DCI includes a resource grant for multiple subframes and multiple codewords in each subframe, and a modulation and coding scheme (MCS) indicator common to the multiple subframes and specific to each of the multiple codewords, where the MCS indicator takes one of multiple values, including a value indicating one of the multiple MCSs and at least one value not indicating an MCS. Correspondingly, the method may further include retrieving (1030) a resource grant (resource allocation (RA)) for the multiple subframes from the DCI and retrieving (1040) an MCS indicator for each of the multiple codewords. Then, an MCS value for a first codeword is evaluated (1050). If the MCS belongs to a value interval not assigned to any MCS (even in the legacy single-subframe allocation) (yes in step 1050), the codeword can be directly set as disabled in the scheduled transmission in step 1060. However, according to another embodiment, further parameter(s) are checked in step 1060 to determine whether the codeword is disabled. The same evaluation is performed for the second (or subsequent) codewords. The check may include evaluation of RV values ​​signaled on a subframe-by-subframe basis, which allows for further subframe-by-subframe control of activation / deactivation. In other words, step 1060 determines that if the MCS indicator for at least one of the codewords has a value that does not indicate MCS (yes in step 1050), then the codewords in the subframes are disabled, and if not (no in step 1050), then they are not disabled. In step 1070, the scheduled data transmission is performed. Specifically, the transmission across the subframes is performed on the assigned (granted) resources using the configured MCS for the enabled codewords.

[0168] The step of assessing the MCS value and corresponding further parameter(s) may include steps corresponding to the functionality of the processing device described with respect to the apparatus above.

[0169] For example, the method may further include retrieving precoding indication information common to multiple subframes from the DCI. The precoding indication information may also be common to both codewords in all subframes. Specifically, a precoding indication information field may be present that indicates the TPMI and the number of layers for both enabled codewords when both codewords are enabled, and indicates the TPMI and the number of layers for one enabled codeword when only one codeword is enabled. If codewords are enabled or disabled on a subframe-by-subframe basis, the method may include retrieving first precoding indication information for subframes in which both codewords are enabled and second precoding indication information when only one codeword is enabled. These indications may be retrieved from two separate fields in the DCI, which may have the same length or may be different. These fields may have a format similar to the current precoding information field in LTE (which signals a combination of TPMI and number of layers). However, for the purpose of conveying control information more efficiently, only one precoding information field may be extracted from the DCI, preferably having a format similar to the precoding information field in the legacy (single-subframe scheduling) configuration with four antenna ports and both codewords enabled. The precoding indication information for one codeword transmission is determined according to a first range of values ​​in this field, and the precoding information when both codewords are enabled is determined according to a second range of values ​​in this field (which is independent of the first range of values). Further alternative methods for determining the precoding indication information for a subframe for one or both codewords are described above in relation to the signal structure and corresponding devices.

[0170] FIG. 10 further illustrates a transmission method that can be performed in a scheduling entity, such as a network node, a base station, an access point, or another terminal that performs scheduling functions. The method can include generating control information (1000). This includes setting a modulation and coding scheme (MCS) indicator to a value that does not indicate MCS to indicate that a codeword from a plurality of codewords in a plurality of subframes is disabled. Then, control information including this MCS field value and additional parameters that can also be set is transmitted to the UE in a transmission signal (1010). The transmitted control information includes, inter alia, resource grants for a plurality of subframes and a plurality of codewords in each subframe, and an MCS indicator that is common to the plurality of granted subframes and specific to each of the plurality of codewords, where the MCS indicator takes one of a plurality of values, including a value indicating one of a plurality of MCSs and at least one value that does not indicate MCS. The control information can also include precoding indication information common to a plurality of subframes, as described above. In step 1090, data is received (and retrieved from resources) in accordance with the control information.

[0171] FIG. 11 illustrates another embodiment of a method according to the present disclosure. A method for receiving resource grants for multiple subframes in a communication system includes receiving a signal containing control information (1120). The control information includes a common resource grant for multiple subframes and multiple codewords in each subframe, and codeword indication information indicating the enabling or disabling of one or more codewords in each of the multiple subframes. Accordingly, the resource grant is retrieved in step 1130, and codeword indication information (CWI) is retrieved in step 1140, thereby determining, for each subframe, whether and / or which codewords from the multiple codewords in that subframe are enabled or disabled according to the codeword indication information. Data is then transmitted (1170) using the configuration received in the control information in step 1120, i.e., on the granted resources in the multiple subframes and with codewords enabled / disabled on a subframe-by-subframe basis according to the retrieved codeword indication information (CWI).

[0172] 11 , a method for transmitting resource grants for multiple subframes in a communication system includes selecting, for each subframe, whether a codeword from a plurality of codewords in that subframe is enabled or disabled, and setting codeword indication information accordingly, thereby generating control information (1100). The method further includes transmitting (1110) a signal including control information including a common resource grant for the multiple subframes and the multiple codewords in each subframe, and codeword indication information indicating the enabling or disabling of one or more codewords in each of the multiple subframes.

[0173] In the context of the embodiments and examples presented herein, the description often states that "one codeword is disabled and one codeword is enabled," etc. In general, and unless otherwise specified, it should be understood, without loss of generality, that an advantageous embodiment of one disabled codeword and one enabled codeword is to enable the first codeword and disable the second codeword (e.g., in the context of FIG. 7, the first codeword is codeword 0 and the second codeword is codeword 1).

[0174] The above description provides examples where activation / deactivation is related to codewords. Note that in LTE, a transport block is mapped to each codeword. This mapping is known to the transmitter and receiver. The mapping can generally be predefined, preconfigured, or controlled by predefined rules. However, the concepts described above can also be applied directly to the activation / deactivation of transport blocks.

[0175] In LTE / LTE-A, if only codeword 0 is enabled, there is still a choice between transport block 1 being mapped to codeword 0 and transport block 2 being mapped to codeword 0, which is particularly relevant when disabling codewords to improve retransmission of previously transmitted transport blocks. The mapping of transport blocks to codewords is specified in Table 5.3.3.1.5-2 of 3GPP TS 2.0 / 10.2, RFC 2568, RFC 2568 for the case where only one codeword (and therefore only one of the two transport blocks) is enabled: [Table 1]

[0176] In the embodiments and examples presented herein, in such a case, it is determined which transport block (1 or 2) is enabled and which transport block (2 or 1) is disabled, and the corresponding enabled transport block is mapped to codeword 0 accordingly. For example, according to the embodiment using the MCS field value to enable / disable codeword(s) described above, if the MCS1 indicator has a value in the range of 29-31, the result is that codeword 0 is disabled and codeword 1 is enabled, and furthermore, transport block 1 is disabled and transport block 2 is mapped to codeword 1. In contrast, if the MCS2 indicator has a value in the range of 29-31, the result is that codeword 0 is enabled and codeword 1 is disabled, and furthermore, transport block 2 is disabled and transport block 1 is mapped to codeword 0. As will be apparent to those skilled in the art, this LTE mapping is one option. However, other rules for mapping between transport blocks and codewords may exist. The present disclosure is applicable using any such rules.

[0177] In summary, the present disclosure provides an apparatus for receiving a resource grant for a plurality of subframes in a communication system, the apparatus comprising: a transceiver that receives a signal comprising: a resource grant for the plurality of subframes and a plurality of codewords in each subframe; precoding indication information common to the plurality of subframes; and a modulation and coding scheme (MCS) indicator that is common to the plurality of granted subframes and individual for each of the plurality of codewords, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of a plurality of MCSs and at least one value that does not indicate an MCS; and a processing device configured to determine to disable a codeword from a plurality of codewords in the plurality of subframes if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS, and to determine not to disable a codeword from a plurality of codewords in the plurality of subframes if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS, and otherwise

[0178] For example, the above multiple values ​​may include 32 indexed values, of which the three values ​​with the highest indexes do not indicate an MCS and may be used to indicate the disabling of codewords for multiple subframes.

[0179] For example, the control information further comprises redundancy version indication information that is individual for each of the plurality of subframes and common to all codewords in the respective subframes, and the processing device is configured to: determine that a codeword from the plurality of codewords in the plurality of subframes is to be disabled if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate MCS and the redundancy version indication information has a first predefined value; and determine that a codeword from the plurality of codewords in the plurality of subframes is not to be disabled otherwise.

[0180] In particular, in a subframe in which one codeword is enabled and one codeword is disabled, the processing device is advantageously configured to determine the redundancy version of the enabled codeword based on a specific value that does not indicate an MCS and that is used together with the redundancy version indication information to indicate the disablement of the disabled codeword.

[0181] Furthermore, in one example, in a subframe in which two codewords are enabled and none of the codewords are disabled, the processing device is configured to determine the MCS of the enabled codeword based on a specific value indicating the MCS, the specific value not being used together with the redundancy version indication information to indicate the disabling of the disabled codeword.

[0182] Advantageously, the precoding indication information indicates a combination of a transmit precoding matrix indication (TPMI) and the number of transmission layers, i.e. indicates a combination of a TPMI and the number of transmission layers from among a plurality of predefined combinations of TPMI and the number of transmission layers, or indicates a combination of a TPMI and the number of transmission layers from among a plurality of combinations of TPMI and the number of transmission layers in a set of candidates that are predefined by semi-static signaling, or indicates a combination of a TPMI and the number of transmission layers from among a plurality of predefined combinations of TPMI and the number of transmission layers that are also selectable in the case of a single-layer configuration using one codeword per subframe, or from among a plurality of predefined combinations of TPMI and the number of transmission layers that are not selectable in the case of a single-layer system, and the value of the precoding indication information indicating each combination of TPMI and the number of transmission layers that is not selectable in the case of a single-layer system is a reserved value in the precoding indication information for the single-layer configuration.

[0183] The present disclosure further provides an apparatus for receiving a resource grant for a plurality of subframes in a communication system, the apparatus comprising: a transceiver that receives a signal comprising control information including a common resource grant for a plurality of subframes and a plurality of codewords in each subframe and codeword indication information indicating enabling or disabling of one or more codewords in each of the plurality of subframes; and a processing device that is configured to determine, for each subframe, whether and / or which codewords from the plurality of codewords in that subframe are enabled or disabled in accordance with the codeword indication information.

[0184] For example, the codeword indication information may be a bitmap that includes an individual bit for each of a number of subframes, each individual bit indicating whether one codeword or two codewords are enabled.

[0185] Advantageously, the control information further comprises a modulation and coding scheme (MCS) indicator common to the grantee subframes and individual to each of the codewords, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of the plurality of MCSs and at least one value not indicative of any MCS, and the processing device is further configured to determine the modulation and coding scheme of each enabled codeword in accordance with the MCS indicator taking a value indicative of one of the plurality of MCSs.

[0186] For example, the processing device is further configured to determine a precoding configuration when a codeword is enabled based on an MCS indicator having a value that does not indicate one of the multiple MCSs, or to determine which codewords are disabled based on an MCS indicator having a value that does not indicate one of the multiple MCSs or based on a redundancy version indicator for a subframe in which a codeword is enabled.

[0187] Corresponding to the receiving apparatus, a transmitting apparatus is provided, particularly an apparatus for transmitting a resource grant for a plurality of subframes in a communication system, the apparatus comprising: a processing device configured to set a modulation and coding scheme (MCS) indicator to a value not indicative of MCS to indicate that a codeword from a plurality of codewords in the plurality of subframes is disabled; and a transceiver for transmitting a signal comprising: a resource grant for the plurality of subframes and a plurality of codewords in each subframe; precoding indication information common to the plurality of subframes; and an MCS indicator that is common to the plurality of granted subframes and individual for each of the plurality of codewords, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of a plurality of MCSs and at least one value not indicative of MCS.

[0188] Further provided is an apparatus for transmitting resource grants for a plurality of subframes in a communication system, the apparatus comprising: a processing device configured to select, for each subframe, whether a codeword from a plurality of codewords in that subframe is enabled or disabled and to set codeword indication information accordingly; and a transceiver configured to transmit a signal comprising control information including a common resource grant for the plurality of subframes and the plurality of codewords in each subframe, and codeword indication information indicating the enabling or disabling of one or more codewords in each of the plurality of subframes.

[0189] Advantageously, the format and content of the transmitted control information is similar to that described above in relation to the receiving device.

[0190] The present disclosure further relates to a method of receiving a resource grant for a plurality of subframes in a communication system, the method comprising: receiving a signal comprising control information including a resource grant for a plurality of subframes and a plurality of codewords in each subframe; precoding indication information common to the plurality of subframes; and a modulation and coding scheme (MCS) indicator that is common to the plurality of subframes being granted and individual for each of the plurality of codewords, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of a plurality of MCSs and at least one value that does not indicate an MCS; and determining to disable a codeword from a plurality of codewords in the plurality of subframes if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS, and determining not to disable a codeword from a plurality of codewords in the plurality of subframes if the MCS indicator for at least one of the plurality of codewords has a value that does not indicate an MCS, and otherwise determining not to disable a codeword from a plurality of codewords in the plurality of subframes.

[0191] Further provided is a method for receiving resource grants for multiple subframes in a communication system, the method comprising: receiving a signal comprising control information including a common resource grant for multiple subframes and multiple codewords in each subframe, and codeword indication information indicating enabling or disabling of one or more codewords in each of the multiple subframes; and determining, for each subframe, whether and / or which codewords from the multiple codewords in that subframe are enabled or disabled in accordance with the codeword indication information.

[0192] Also provided is a corresponding transmission method, in particular a method for transmitting resource grants for a plurality of subframes in a communication system, comprising: setting a modulation and coding scheme (MCS) indicator to a value not indicative of MCS to indicate that a codeword from a plurality of codewords in the plurality of subframes is disabled; and transmitting a signal comprising control information including the resource grants for the plurality of subframes and the plurality of codewords in each subframe, precoding indication information common to the plurality of subframes, and an MCS indicator common to the plurality of granted subframes and individual for each of the plurality of codewords, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of a plurality of MCSs and at least one value not indicative of MCS.

[0193] Further provided is a method for transmitting resource grants for a plurality of subframes in a communication system, the method comprising: selecting, for each subframe, whether a codeword from a plurality of codewords in that subframe is enabled or disabled and setting codeword indication information accordingly; and transmitting a signal comprising control information including a common resource grant for the plurality of subframes and the plurality of codewords in each subframe, and codeword indication information indicating the enabling or disabling of one or more codewords in each of the plurality of subframes.

[0194] The format and content of the control information may advantageously be the same as that described above in relation to the receiving device and exemplified in the disclosure above.

[0195] According to another embodiment, there is provided a (non-transitory) computer readable medium having stored thereon a program which, when run on a computer, performs the steps of the method described above.

[0196] Hardware and Software Implementations of the Disclosure Another exemplary embodiment relates to implementing the various embodiments described above using hardware, software, or software in conjunction with hardware. In this regard, a user terminal (mobile terminal) and an eNodeB (base station) are provided. The user terminal and the base station are configured to perform the methods described herein and include corresponding entities (receivers, transmitters, processors, etc.) appropriately involved in these methods.

[0197] It will be further recognized that various embodiments may be implemented or performed using a computing device (processor). Examples of computing devices or processors include general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices. Various embodiments may also be implemented or embodied using a combination of these devices. In particular, the functional blocks used to describe the above-described embodiments may be implemented using an LSI, which is an integrated circuit. These functional blocks may be configured on individual chips, or a single chip may contain some or all of the functional blocks. These chips may include data inputs and outputs coupled to them. LSIs are referred to as ICs, system LSIs, super LSIs, or ultra LSIs depending on the level of integration. However, the technology for implementing an integrated circuit is not limited to LSIs and can be achieved using dedicated circuits or general-purpose processors. Furthermore, an FPGA that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections or settings of circuit cells within an LSI, may be used.

[0198] Furthermore, the various embodiments may also be implemented by means of software modules, which are executed by a processor or directly in hardware. A combination of software modules and hardware implementation is also possible. The software modules may be stored on any kind of computer-readable storage medium, for example RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc. Furthermore, it should be noted that individual features of the different embodiments may also be the subject of other embodiments, individually or in any combination.

[0199] It will be appreciated by those skilled in the art that various changes and / or modifications may be made to the present disclosure as set forth in the specific embodiments without departing from the concept or scope of the invention as broadly described. The embodiments described herein are therefore to be considered in all respects as illustrative and not restrictive.

[0200] In summary, the present disclosure relates to enabling and disabling codewords in a multi-subframe grant. Specifically, codewords can be dynamically enabled / disabled on a per-subframe basis, even when other control parameters, including resource allocation, are implemented across multiple subframes. For example, a signal from a scheduling entity to a scheduled entity includes control information including a common resource grant for multiple subframes and multiple codewords in each subframe, and codeword indication information indicating the enabling or disabling of one or more codewords in each of the multiple subframes. For each subframe, whether and / or which codewords from the multiple codewords in that subframe are enabled or disabled is determined according to the codeword indication information. Alternatively, the enabling and disabling indication can be performed using a modulation and coding scheme indicator value that is not associated with a specific modulation and coding scheme.

Claims

1. 1. An integrated circuit for controlling user equipment for receiving resource grants for a plurality of subframes in a communication system, the integrated circuit comprising: the resource grant for a plurality of subframes and a plurality of codewords in each subframe; Precoding instruction information common to the plurality of subframes; a modulation and coding scheme (MCS) indicator that is common to a plurality of subframes granted and that is individual to each of the plurality of codewords in each subframe, the MCS indicator taking one of a plurality of values ​​including a value indicative of one of a plurality of MCSs and at least one value that does not indicate an MCS; a receiving circuit for receiving a signal comprising control information including: a control circuit configured to disable the first codeword or the second codeword depending on whether a different redundancy version (RV) for each subframe indicates a first RV state or a second RV state when the plurality of codewords includes a first codeword and a second codeword, and when a first MCS indicator has a value indicating one of the MCSs and a second MCS indicator has a value indicating no MCS; having Integrated circuit.

2. If the RV indicates a first RV state, the first codeword is invalidated, and if the RV indicates a second RV state, the second codeword is invalidated.

10. The integrated circuit of claim 1.

3. The precoding instruction information indicates a combination of a transmit precoding matrix instruction information (TPMI) and a number of transmission layers.

10. The integrated circuit of claim 1.

4. The combination of the TPMI and the number of transmission layers is A combination of TPMI and number of transmission layers among a plurality of predefined combinations of TPMI and number of transmission layers.

4. The integrated circuit of claim 3.

5. The combination of the TPMI and the number of transmission layers is A combination of TPMI and number of transmission layers among a plurality of combinations of TPMI and number of transmission layers in a candidate set pre-configured by semi-static signaling.

4. The integrated circuit of claim 3.

6. The combination of the TPMI and the number of transmission layers is a combination of a TPMI and a number of transmission layers among a plurality of predefined combinations of a TPMI and a number of transmission layers that are selectable even in the case of a single-layer configuration using one codeword per subframe, or among a plurality of predefined combinations of a TPMI and a number of transmission layers that are not selectable in the case of a single-layer configuration, and a value of the precoding indication information indicating each combination of a TPMI and a number of transmission layers that is not selectable in the case of a single-layer system is a reserved value in the precoding indication information for a single-layer configuration; 4. The integrated circuit of claim 3.

Images