User Equipment and Methods

Abstract

To use multi-subframe allocation while providing efficient smallest units of control information.SOLUTION: The present disclosure relates to enabling / disabling codewords in multi-subframe grants. Specifically, codewords can be enabled / disabled dynamically in units of subframes even if other control parameters including resource allocation are performed for multiple subframes. A signal from a scheduling entity to a scheduled entity comprises control information including: a common resource grant for multiple subframes and a plurality of codewords for each subframe; and codeword indication information indicating enabling / disabling codewords for each of the multiple subframes. For each subframe, it is determined whether a 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 a communication system 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 deployed on a wide scale around the world. As a first step in enhancing or evolving this technology, High-Speed ​​Downlink Packet Access (HSDPA) and 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 from users and to ensure competitiveness against new radio access technologies, 3GPP has introduced a new mobile communication system called Long Term Evolution (LTE). LTE is designed to accommodate carriers' demands for high-speed transmission of data and media, as well as high-capacity voice support, for the next decade. The ability to provide high bit rates is a key feature of LTE.

[0004] The LTE system is a packet-based, efficient 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 with 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 cyclic prefix (CP), and is compatible with various transmission bandwidth configurations. Single-Carrier Frequency Division Multiple Access (SC-FDMA)-based radio access is adopted for the uplink. Because, given the limited transmission power of the User Equipment (UE), providing a wider coverage area takes priority over improving the peak data rate. LTE Release 8 / 9 adopts a number of key packet radio access technologies (e.g., Multiple Input Multiple Output (MIMO) channel transmission technology) and achieves a highly efficient control signaling structure.

[0005] [LTE architecture] Figure 1 shows the overall architecture of LTE. E-UTRAN consists of eNodeB, which terminates E-UTRA user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) protocols towards 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 the user plane header compression and encryption functions. The eNB also provides the radio resource control (RRC) functions corresponding to the control plane. The eNB performs many functions, such as radio resource management, admission control, scheduling, enforcing uplink quality of service (QoS) through negotiation, broadcasting cell information, encrypting / decrypting user and control plane data, and compressing / decompressing downlink / uplink user plane packet headers. The Radio Resource Control (RRC) layer controls the communication between UEs and eNBs on 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 the notification of an incoming call from the network. The 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, establishment of Signalling Radio Bearers (SRBs) and radio bearers carrying user data (Data Radio Bearers (DRBs)). Multiple eNodeBs are connected to each other by the X2 interface.

[0006] The eNodeBs are also connected to the EPC (Evolved Packet Core) by the S1 interface, more specifically to the MME (Mobility Management Entity) by the S1-MME and to the Serving Gateway (SGW) by 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 acting as a mobility anchor for the user plane during handovers between eNodeBs. Furthermore, the SGW acts as an anchor for mobility between LTE and other 3GPP technologies (terminating the S4 interface and relaying traffic between 2G / 3G systems and the PDN GW). For idle user equipment, the SGW terminates the downlink data path and triggers paging when downlink data arrives for that user equipment. The SGW manages and stores the user equipment context (e.g. parameters of IP bearer services 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, it is responsible for selecting the SGW for the user equipment at initial attach and during intra-LTE handover involving Core Network (CN) node relocation. It is responsible for authenticating the user (by interacting with the HSS). Non-Access Stratum (NAS) signaling is terminated in the MME. It is also responsible for generating and assigning temporary identities to user equipment. It checks the authorization of user equipment to enter the service provider's Public Land Mobile Network (PLMN) and enforces roaming restrictions for user equipment. It 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. In addition, the MME provides the control plane function for mobility between LTE and 2G / 3G access networks and terminates 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 of the OFDM symbols is therefore composed 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 It 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 N = 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. For the normal cyclic prefix subframe structure, N RB sc =12, N DL symb = 7. For the uplink, the grid shown in Figure 2B is provided, see also in this respect Figures 6.2.2-1 and 5.2.1-1 of Non-Patent Document 1.

[0009] Considering a multi-carrier communication system, e.g. using OFDM, as used in 3GPP LTE, the smallest unit of resources 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. 7 OFDM symbols) and consecutive subcarriers in the frequency domain (e.g. 12 subcarriers of a component carrier), as illustrated in Fig. 2. Thus, in 3GPP LTE (Release 8), a physical resource block is composed 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 e.g. Section 6.2 of 3GPP LTE 2011-010621 (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" cyclic prefix (CP) is used, and 12 OFDM symbols in a subframe when the so-called "extended" CP is used. For the purpose of terminology, in the following, a time-frequency resource equivalent to the same consecutive subcarriers spread over an entire subframe is 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 frequency of the downlink resources and the carrier frequency of the uplink resources is indicated in the system information transmitted on the downlink resources.

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

[0013] [Carrier aggregation in LTE-A to support wider bandwidth] The LTE-Advanced system can support a bandwidth of 100 MHz, while the LTE system can only support 20 MHz. In carrier aggregation, two or more component carriers are aggregated in order 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 one wider channel. This channel is wide enough for 100 MHz even if these cells in LTE are in different frequency bands. A user equipment can simultaneously receive or transmit on one or several component carriers (corresponding to several serving cells) depending on the user equipment 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 downlink primary cell (PCell). In connected state, there is always one downlink PCell (DL PCell) and one uplink PCell (UL PCell) configured per user equipment. In the configured set of component carriers, the other cells are called secondary cells (SCell), and the carriers of the SCell are downlink secondary component carriers (DL SCC) and uplink secondary component carriers (UL SCC). Up to five serving cells (including PCell) can be configured for one UE.

[0015] [LTE uplink access method] In uplink transmission, user terminals need to transmit with high power efficiency to maximize coverage. Single-carrier transmission combined with FDMA with dynamic bandwidth allocation has been selected as the uplink transmission scheme for E-UTRA. Single-carrier transmission has been selected primarily due to its lower peak to average power ratio (PAPR) compared to multi-carrier signals (OFDMA), which results in a corresponding improvement in power amplifier efficiency and improved coverage (higher data rate for a given terminal peak power). In each time interval, the eNodeB assigns each user a unique time / frequency resource for transmitting user data. This ensures intra-cell orthogonality. Orthogonal multiple access in the uplink increases 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 smallest 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 the 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 the downlink data in a subframe (assuming that user allocation can vary per subframe). Note that user allocation can also be performed on a TTI (Transmission Time Interval) basis. In that case, it is possible that the TTI length is an integer multiple of a subframe. The TTI length can be constant for all users in a service area, or different for different users, or even dynamic for each user. L1 / L2 control signaling generally only needs to be transmitted once per TTI. In the following, it is assumed, without loss of generality, that the TTI is equal to one subframe.

[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. In general, several PDCCHs can be transmitted within one subframe.

[0019] It should be noted that in 3GPP LTE, assignments for uplink data transmissions (also called uplink scheduling grants or uplink resource assignments) are also transmitted on the PDCCH. Furthermore, Release 11 introduces the EPDCCH, which basically performs the same function as the PDCCH (i.e. carries Layer 1 / Layer 2 control signaling), but the details of the transmission method are different from the PDCCH. Further details can be found, inter alia, in the current version (e.g. version 13.2.0) of 3GPP LTE 2011 / 02 / 1 ...

[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 which 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 (RB)) 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 the second carrier or resources related to the second carrier) (cross-carrier scheduling). - Modulation and Coding Scheme: Determines the modulation scheme and coding rate to be adopted. - HARQ information: such as New Data Indicator (NDI) or Redundancy Version (RV), which is particularly useful when retransmitting a data packet or parts of it. - Power control command: adjusts the transmission power of the assigned uplink data or control information transmission. - Reference signal information: e.g. the applied cyclic shift or Orthogonal Cover Code (OCC) index used for transmission or reception of the reference signal to be allocated. - Uplink assignment index or downlink assignment index: Used to identify the order of assignments, especially useful in TDD systems. - Hopping information: e.g. an indication of whether and how to apply resource hopping for the purpose of increasing frequency diversity. - CSI Request: Used to trigger the transmission of Channel State Information on 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 by 3GPP LTE-(A) Release 10.

[0021] It should be noted that the above list is not exhaustive and depending on the DCI format used, not all 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, the 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 been considered to date 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 2.0, 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. This LTE specification (3GPP TS 2.0) contains a two-dimensional TBS table in section 7.1.7.2, 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. In particular, the first column represents the MCS indexes to be included in the DCI. Each MCS index 0-28 is associated with a specific combination of modulation order (2=QPSK, 4=16QAM, 6=64QAM) and 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 (e.g. redundancy version 0) transmission of the same transport block.

[0026] The redundancy version (RV) specifies the starting point in the circular (re)transmit buffer to begin the read operation. For the first transmission, which mainly sends systematic bits, RV=0 is usually chosen because this method represents a good compromise between successful decoding at high signal-to-noise ratios (SNR) and successful decoding at low SNR. The scheduler can choose different RVs for transmissions of the same packet to support both incremental redundancy (IR) combining and Chase combining. Currently, four redundancy versions are defined, each characterized by its starting position, numbered 0-3. 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 in 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). Furthermore, for further details regarding DCI formats and the specific information transmitted in DCI, the reader is referred 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 transmission of 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 transmission of 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 allocations 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 for compact signaling of resource allocation for PDSCH transmission (downlink transmission mode 6) using closed-loop precoding with rank-1 transmission. The transmitted information is the same as in Format 1A, but in addition an indicator of the precoding vector applied to the PDSCH transmission is included. - Format 1C: DCI Format 1C is used for a very compact transmission of PDSCH assignments. 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 and to broadcast system information messages. - Format 1D: DCI Format 1D is used for compact signaling of 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 indicator of the precoding vector, there is one bit to indicate if a power offset is applied to the data symbols. This feature is necessary to indicate whether the transmission power is shared between two UEs or not. In future versions of LTE, this feature can be extended to the case of power sharing between a larger number of UEs. - Format 2: DCI Format 2 is used for transmitting resource allocations for the 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 for Format 2, with the exception that no precoding information is present if the eNodeB has two transmit antenna ports, 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, it is used to transmit resource allocations for PDSCH in case of dual layer beamforming (transmission mode 8). - Format 2C: Introduced in Release 10, it is used for transmitting resource allocations for the PDSCH in case of closed-loop single-user MIMO 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 the PUSCH using closed-loop spatial multiplexing transmission in uplink transmission mode 2.

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

[0029] A search space indicates a set of CCE locations where a UE can find a PDCCH to itself. Each PDCCH carries one DCI and is identified by an RNTI (Radio Network Temporary Identifier) ​​that is implicitly coded in a CRC appended 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 common search space and UE-specific search space. The UE needs to monitor both common search space and UE-specific search space (which may overlap). The common search space carries DCI that is common to all UEs, such as system information (using SI-RNTI), paging (P-RNTI), PRACH response (RA-RNTI), or UL TPC command (TPC-PUCCH / PUSCH-RNTI). The UE-specific search space carries DCI for UE-specific assignment (using UE-allocated C-RNTI), 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 pre-processing of the data to be transmitted and time- or frequency-domain decoding of the received data, the use of additional antenna elements at either the base station (eNodeB) or the user equipment (UE) (in the downlink or uplink) opens an additional spatial dimension for signal precoding and detection. Space-time processing techniques exploit this dimension with the aim of improving the performance of the link in terms of one or more possible metrics, such as error rate, communication data rate, coverage area, and spectral efficiency (units: bps / Hz / cell). Such 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 communicating simultaneously with a common base station using the same frequency and time domain resources.

[0032] The LTE standard defines so-called "antenna ports" (see 3GPP TS 2.0, section 5.2.1). Antenna ports do not correspond to physical antennas, but are logical entities differentiated by their reference signal sequence. 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 produced 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 corresponding to one Transport Block (TB) passed from the Medium Access Control (MAC) layer to the physical layer at the transmitter and protected by a CRC. For a rank of 2 or higher, 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 fast 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 in order to demodulate 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 the 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 layers to be transmitted and the 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 bands was initiated in June 2015. The reason for extending LTE to unlicensed bands is the limited amount of licensed bands combined with the ever-growing demand for wireless broadband data. Unlicensed bands are therefore increasingly seen as a supplementary means by mobile operators to expand their service offerings. The advantage of LTE in unlicensed bands, compared to relying on other radio access technologies (RATs) such as Wi-Fi, 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 platform with access to unlicensed bands.

[0038] However, it must be taken into account that access to unlicensed spectrum can never be comparable in quality to licensed spectrum access, since it necessarily coexists with other radio access technologies (RATs) in unlicensed spectrum. Therefore, LTE operation in unlicensed spectrum will, at least initially, not be seen as a standalone operation in unlicensed spectrum, but rather as a complement to LTE in licensed 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, future standalone operation of LTE in unlicensed spectrum without relying on Licensed Assisted Access (LAA) is not excluded.

[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 includes a so-called Primary Cell (PCell) carrier and one or more Secondary Cell (SCell) carriers, as described above. 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 in PDCCH / EPDCCH and user data in PDSCH / PUSCH are transmitted on different carriers).

[0040] The basic approach envisaged in 3GPP is to operate the PCell in licensed bands while one or more SCells are operated in unlicensed bands. The advantage of this approach is that the PCell can be used to reliably transmit control messages and user data requiring high quality of service (QoS) (e.g. voice and video), while the SCells in unlicensed bands necessarily coexist with other radio access technologies (RATs), which may significantly degrade the QoS to different degrees depending on the scenario. Figure 3 shows a very basic scenario, with a licensed PCell, a licensed SCell 1 and various unlicensed SCells 2, 3, 4 (illustratively depicted as small cells). The transmitting / receiving network nodes for the unlicensed SCells 2, 3, 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 to the network are not explicitly shown in the figure.

[0041] It was agreed in 3GPP that the study and specification of LAA (Licensed Assisted Access) will focus in the first phase on unlicensed bands in 5 GHz. One of the most important issues is therefore the coexistence with Wi-Fi (IEEE 802.11) systems operating in these unlicensed bands. In order to support a fair coexistence between LTE and other technologies (such as Wi-Fi) and also to ensure fairness between different LTE operators in the same unlicensed band, the 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 considered. A comprehensive description of the regulatory requirements for operation in the 5 GHz unlicensed bands is given 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 Dynamic Frequency Selection (DFS), Transmit Power Control (TPC), Listen Before Talk (LBT), Discontinuous Transmission with limited maximum transmission time length, depending on the region and band. 3GPP's intention is to target a single international framework for LAA, which basically means that all the requirements for the different regions and the 5GHz band must be taken into account when designing the 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, but can then rely on another device associated to it. According to the European regulations on LBT (Listen Before Talk), the device must perform a Clear Channel Assessment (CCA) before occupying a radio channel. It is only allowed to start transmitting on an unlicensed channel after the channel has been detected as free, for example based on energy detection. The device must monitor the channel during CCA 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 free, the device is allowed to transmit immediately. This limits the maximum duration of a transmission with the aim of promoting 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 in that channel contribute to the energy level evaluated in the device performing CCA.

[0044] Furthermore, the total time that a device occupies a given unlicensed channel by continuous transmission without re-evaluating the channel availability (i.e. LBT / CCA) is defined as the Channel Occupancy Time (see section 4.8.3.1 of 3GPP TS 2013-2016). The Channel Occupancy Time is in the range of 1 ms to 10 ms, and the maximum Channel Occupancy 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 that channel, and the minimum idle time is at least 5% of the previous channel occupancy time. For example, a UE can perform a new CCA at the end of an Idle Period. This transmission behavior is shown diagrammatically in Figure 4.

[0045] [Multiple subframe allocation] In 3GPP RAN1, the possibility of multi-subframe scheduling in uplink LAA has been studied (see non-patent document 8). As a consequence, 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 the scheduled LAA UE receives the UL grant in subframe n, it needs to perform LBT on the scheduled unlicensed carrier to occupy the channel before starting PUSCH transmission in subframe n+4 based on FDD HARQ timing. When sending the UL grant in subframe n, the eNB cannot predict the result of LTB on the UE side, and has no choice but to send the UL grant expecting 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, which results in not only wasting resources for the UL grant but also wasting UL resources for PUSCH transmission. The LAA UL transmission should be designed to increase the channel access opportunity of LAA with less scheduling overhead.

[0047] In order to increase channel access opportunities while minimizing the signaling overhead for scheduling PUSCH in unlicensed carriers, multi-subframe scheduling is considered. In multi-subframe scheduling, a UE can transmit PUSCH in one or more subframes in a scheduled subframe with one UL grant upon successful LBT. 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

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 that utilizes 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 for receiving 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 control information comprising a modulation and coding scheme (MCS) indicator that is common to the plurality of subframes being granted and separate 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 MCS; and a processing device configured to determine that a codeword from a 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 to determine that a codeword from a plurality of codewords in the plurality of subframes is not to be disabled otherwise.

[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 comprising: a transceiver for receiving 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 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, and these benefits and / or advantages may be obtained individually by various embodiments and features of the specification and drawings, and it is not necessary for all of the embodiments and features to be provided in order to obtain one or more of such benefits and / or advantages.

[0054] In the following, exemplary embodiments are explained in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0055] [Figure 1] 1 illustrates an example architecture of a 3GPP LTE system. [Figure 2A] 1 illustrates an example downlink resource grid of a downlink slot of a subframe defined in 3GPP LTE (Release 8 / 9). [Figure 2B]1 illustrates an example uplink resource grid of uplink slots of a subframe defined in 3GPP LTE (Release 8 / 9). [Diagram 3] 1 illustrates an example scenario of licensed assisted access involving various licensed and unlicensed cells. [Figure 4] 1 illustrates a schematic diagram of transmission timing in an unlicensed band, including various periods: channel occupancy time, idle period, and fixed frame period. [Diagram 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 the case of 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 example OFDM transmitter for the downlink. [Figure 10] 1 is a flow diagram illustrating a method according to one embodiment. [Figure 11] 1 is a flow diagram illustrating a method according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 means a software or hardware module that performs a given set of functions and / or provides a given 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 a communication device or medium through which the node can communicate. Similarly, a network entity may have logical interfaces that attach the functional entity to a communication device or medium through which the network entity can communicate with another functional entity or a correspondent node.

[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 term "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 term "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 at the MAC layer, a certain 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 mentioned 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 the sake of 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". It should therefore be understood that the embodiments and examples also apply to enabled / disabled transport blocks in addition to or instead of being applied 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 in unlicensed carriers. Specifically, the left column lists the fields of the DCI. 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 case of multi-subframe grants. DCI Format 0B and DCI Format 4B are meant to accompany the currently used DCI Format 0 and DCI Format 4.

[0062] DCI format 4 is currently used for scheduling PUSCH in one UL cell for 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 word "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 a multi-subframe grant. That is, DCI format 0B is applicable to single antenna port transmission, whereas DCI format 4B is applicable to multi-antenna port transmission. As can be seen in the table of 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. Thus, the usage of some DCI fields by formats 0B and 4B may differ. In FIG. 6, when multiple codewords are present, a modulation and coding scheme can be advantageously provided for each codeword. However, providing an MCS for each subframe is considered unnecessary, since it is unlikely that the channel quality will change inherently at such a fast rate, and it is not clear that the eNB can have sufficient information about the fast-changing channel conditions to use such information when transmitting the 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 FIG. 6, some of the fields are provided for each of the multiple subframes. For example, a new data indicator is needed for each subframe because each subframe carries different data (because different TTIs are mapped to each subframe) and therefore each subframe can be retransmitted separately. Correspondingly, a redundancy version is also needed on a subframe basis. Note that the redundancy version in the legacy DCI of formats 0 and 4 is selected from a set of four predefined values. In the table of FIG. 6, the redundancy version is a separate field, with one bit per subframe. In general, one bit to distinguish between two values ​​of the redundancy version should be sufficient, since it is assumed 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 FIG. 6 is merely an example of a new DCI format for multi-subframe grants, as this table merely summarizes the current state of the discussion and is still subject to change.

[0066] All fields shown in Figure 6, except for the "Number of scheduled subframes" field, are also applicable to new DCI formats for scheduling resources on unlicensed carriers for one subframe (tentatively 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 for the subframes shown.

[0067] Regarding multi-layer transmission, previous releases of LTE offered different mechanisms to disable 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 certain 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 (in the uplink there is no MIMO in this release) by using DCI format 2 and DCI format 2A (plus format 2B, format 2C, and format 2D introduced in later LTE releases). If the MCS index is equal to 0 (I MCS =0) and the 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 that can be set, 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 0,2,3,1 of applied redundancy versions.

[0068] In Release 13, two further possible methods for disabling codewords were defined. A codeword is disabled for certain combinations of MCS index and number of physical resource blocks (PRBs) in DCI format 4. Specifically, in DCI format 4, if 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 invalidated. 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 that there is a power limit in the uplink. If the smallest MCS is used, it means that the channel conditions are not particularly good. With only one PRB, a higher power can be applied so that a successful transmission is possible. However, as the number of PRBs increases, the power is spread and the probability of correct reception is low. 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, for the largest MCS index that defines the MCS, it is likely that the channel quality is very high. Therefore, it is unlikely that only one PRB is set 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 result in 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 values ​​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 to this, 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 allocatable unit in the system (PRB in LTE). Thus, the enabling / disabling of one or more codewords can be indicated by a particular 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 exhibits 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 allocatable PRBs (e.g. allocating a number of PRBs greater than 10 in the case of LAA). - The maximum MCS index (e.g. MCS=28, the MCS exhibiting the least robust modulation and coding rate) and the number of PRBs to be allocated equal to the predefined or preconfigured minimum allocatable number of PRBs (e.g. allocate 10 PRBs in 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 preconfigured minimum allocable unit dictates that one codeword is nullified in each subframe scheduled by that DCI, and / or the combination of the largest MCS index and allocating PRBs of the predefined or preconfigured minimum allocable unit dictates that one codeword is nullified in each subframe scheduled by that DCI.

[0076] According to one embodiment, one or more of the MCS levels traditionally 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 multiple subframes granted and specific to each of the multiple codewords. The MCS indicator can take one of a plurality of values ​​including a value indicating one of the multiple MCSs and at least one value not indicating MCS. The MCS indicator for at least one of the multiple codewords having a value not indicating MCS signals disabling of the codeword.

[0079] For example, the control information in the case of two transmission layers includes two MCS fields (MCS1, MCS2) for two respective codewords. The MCS table can be kept the same as in the current LTE standard (see FIG. 5) and the control information can correspond to Dedicated Control Information (DCI) with a format used for multi-subframe grants (such as DCI format 4B mentioned 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, 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. On the other hand, 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 the MCS, which disables the 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, since 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 single layer beamforming is supported 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 needed to nullify codewords. This provides an efficient way to nullify codewords while still allowing the most important link adaptation.

[0082] However, the present disclosure is not limited by the above example where codeword disabling is indicated only by a particular value of the MCS indicator. For example, in order to support subframe-based codeword disabling, in addition to the MCS level, a different redundancy version (RV) field can be used for each subframe. 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 particular MCS indicator (field) and the value of a subframe-specific RV field may work together to indicate the codewords that are enabled / disabled and the redundancy version that is applied.

[0084] For example, if MCS1 has a value in the range 0-28 and MCS2 has value 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. the retransmission is 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. the retransmission is 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 30, then if a first RV state is indicated, codeword 0 is disabled. Codeword 1 (CW1) uses MCS1 and RV0 (either as 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 to 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 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 only describes how the disabling or enabling of codewords can be signaled on a subframe-by-subframe basis by interpreting the combination of the value of the MCS indicator and the value of the redundancy version field without including additional fields in the control information. In general, for two codewords, one MCS indicator (among 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 ​​from 29 to 31 and MCS2 takes values ​​from 0 to 28. For example, such a combination may signal that further redundancy version values ​​are applied.

[0089] In the above example, one advantage is that the MCS table currently defined in LTE can be reused. The MCS indicator thus maintains a length of 5 bits where 32 possible MCS values ​​are represented. In legacy uplink grants, these values ​​are used to indicate MCS (values ​​0-28) and non-zero redundancy versions (values ​​29-31). In uplink multi-subframe grants, these values ​​can be used to indicate MCS (values ​​0-28) and codeword activation / deactivation (values ​​29-31). However, it should be noted that these do not limit the present disclosure. In general, there may be more than two layers and thus more than two codewords. The MCS can thus indicate which codewords are disabled in all subframes or per subframe (possibly using a combination of several MCS indicator values ​​and RV field values ​​as shown above for two codewords).

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

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

[0092] [TPMI Decision] For multi-subframe scheduling supporting 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 indicating a 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 that 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 36.210 (freely available on the 3GPP website and incorporated herein by reference).

[0094] FIG. 7 shows the values ​​of the precoding information field and the corresponding meaning of these values ​​for two antenna ports (FIG. 7A) and four antenna ports (FIG. 7B). These tables correspond to tables 5.3.3.1.8-2 and 5.3.3.1.8-3 in 3GPP TS 2010-01136-11, respectively. In particular, FIG. 7A shows two tables (one for the first two columns and one for the next two columns) for one enabled codeword and two enabled codewords, respectively. In the first and third columns, the values ​​of the bit fields of the precoding information contained in the DCI are shown. In the second and fourth columns, the corresponding associated combinations of the number of layers and the TPMI are specified. If one codeword is enabled, six different values ​​of the TPMI can be selected, corresponding to the indexes 0 to 5 of the precoding information field. The indexes 6 and 7 are reserved. If both codewords are enabled, currently only one TPMI corresponding to index 0 is supported, whereas the indexes 1 to 7 are reserved.

[0095] In Figure 7B, if one codeword is enabled, entries 0 to 39 indicate the combination of the number of layers (which can be 1 or 2) and the TPMI (which can have values ​​0 to 23). Values ​​40 to 63 in the precoding information field are reserved. On the other hand, if both codewords are enabled, values ​​0 to 28 in the precoding information field indicate the combination of the number of layers (which can be 2 to 4) and the TPMI (which can have 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 3GPP TS 2011-011011, 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 3GPP TS 2011-011011. A codebook index is associated with a particular precoding matrix.

[0097] In order to keep the overhead cost of the signaling information as small as possible while at the same time keeping 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 no information about changing channel conditions is available. In contrast, it may be advantageous to provide the number of layers and TPMI of individual subframes for a 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 on a subframe basis, 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 (here it is assumed that the first precoding information field in the case where both codewords are enabled is also included in the DCI). The second field may indicate the number of layers and TPMI in a similar manner to that shown in FIG. 7. In other words, the DCI including the multi-subframe grant may indicate, subframe by subframe, whether one or two codewords are enabled. Thus, two precoding information fields may be provided, namely a first precoding information field indicating the number of layers and TPMI in the case where both codewords are enabled, and a second precoding information field indicating the number of layers and TPMI in the case where only one codeword is enabled. These two precoding information fields may be defined in a similar manner to that shown in FIG. 7.

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

[0101] With reference to the left part of the table in FIG. 7B as an example, the number of selectable TPMIs for each number of transmission layers is sub-sampled so that the total number of options is reduced. For example, instead of allowing all TPMI values ​​0 to 23 to be selected in the case of 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, in the case of 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.), since a regular pattern would generally not fully utilize the capacity of the bit field signal. That is, as just explained, subsampling by a factor of 2 requires a field size of 5 bits, but this subsampling utilizes only 20 of the possible 32 states. Utilization of all 32 states can be achieved, as an example, by selecting 16 TPMI values ​​(out of the 24 defined TPMI values) for 1-layer transmission and keeping the 16 TPMI values ​​for 2-layer transmission. Such uneven subsampling is advantageous to support a more optimized 2-layer transmission. An alternative is to keep the 24 TPMI values ​​for 1-layer transmission and select 8 TPMI values ​​(out of the 16 defined TPMI values) for 2-layer transmission. The latter can be easily achieved by subsampling the 16 values ​​by a factor of 2 (e.g., selecting only the even TPMIs or selecting only the odd TPMIs). In this way, all the options of TPMI for one-layer transmission are reserved, which is advantageous for achieving an optimal SINR in the extended coverage of the uplink signal. Similarly, if only, for example, 3 bits are to be used in the second precoding information field, the total number of 40 different combinations of the number of layers and TPMI needs to be subsampled to 8 combinations. This can be achieved by subsampling the 24 TPMIs defined for one layer by a factor of 3 and not including any TPMIs for two layers.

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

[0104] The 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 is provided that is applicable to subframes where no codewords are disabled, a second precoding information field is provided that is applicable to subframes where a first non-zero number of codewords are disabled, a third precoding information field is provided that is applicable to subframes where a second non-zero number of codewords are disabled, etc. In other words, the number of precoding information fields is typically capped at the maximum number of codewords that may be enabled in a subframe, and preferably corresponds 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 set (e.g., by the Radio Resource Control Protocol (RRC)). In other words, the precoding information for both codewords (see the right side of Fig. 7A and Fig. 7B) is included in the DCI carrying the multi-subframe grant, and the precoding information for the case where only one codeword is enabled is signaled by the RRC. The TPMI for two codewords is primarily aimed at minimizing the interference between the two codewords, and the TPMI for one codeword is primarily aimed at improving the SINR through beamforming. The optimal beam direction of beamforming coincides with the line of sight between the transmitter and the receiver in many scenarios, and the line of sight is relatively unchanged in the case of terminals that do not move much. Conversely, the optimal precoder for minimizing intersymbol interference attempts to eliminate correlation between channels as much as possible in many scenarios, which can be expected to depend more on obstacles in the radio wave propagation environment and therefore 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 the 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 set by semi-static signaling, and the precoding information for one enabled codeword is included in the DCI format. This scheme is particularly applicable when the number of layers and the number of available choices of the TPMI are significantly higher in the case of one codeword than in the case of two codewords. For example, referring to FIG. 7A, in the case of two codewords, there is only one valid entry. From this point of view, it is even possible to operate without a corresponding precoding information field in the DCI. Conversely, in the case of one codeword, there are six different entries as choices, and therefore it can be predicted that the optimal choice of the TPMI may be different even if the channel conditions change slightly.

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

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

[0109] According to a third example, candidates of precoding information for one codeword are semi-statically configured. Furthermore, a specific selection of precoding information among the semi-statically pre-configured candidates is dynamically signaled, for example by using some values ​​of MCS and / or RV. For example, MCS value 29, MCS value 30, and MCS value 31 can be used to indicate the selection of the first candidate, the second candidate, and the third candidate, respectively. The first candidate, the second candidate, and the third candidate can be configured by RRC by assigning a specific combination to these candidates, such as the combinations 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 a first, second, and third candidate, respectively, while MCS values ​​29, 30, and 31 may be used with a second RV value to indicate selection of a fourth, fifth, and sixth candidate, respectively. The first through sixth candidates 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 the case where more than two codewords are supported and at least one codeword is disabled. The number of disabled codewords (and index) can be determined from knowledge of whether the corresponding MCS field contains values ​​from 0 to 28 (i.e. assigning a modulation and coding scheme) or from 29 to 31. This opens up a further dimension in terms of the number of layers and the number of semi-statically pre-configured candidates for precoding. For example, in the case where 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 taking values ​​from 0 to 28 and a second and a third MCS field taking values ​​from 29 to 31, respectively. Thus, the two MCS fields, each indicating 29 to 31, together provide nine different options, which can be used to represent nine different combinations of the number of transmission layers and the TPMI. The number of configurable combinations can be further increased by using the 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 in the case of two codewords in legacy systems, i.e. for four antenna ports, it has 6 bits and 29 possible values, the remaining values ​​are reserved. Values ​​0 to 28 represent the index of the combination of layer number and TPMI value. Values ​​29 to 63 are reserved. In this example, the reserved values ​​are used to convey the 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 combination of TPMI and layer number as used by DCI format 4. In the case where only one codeword is enabled, values ​​29 to 56 indicate the combination (TPMI and layer number) for one enabled codeword. The combinations associated with values ​​0 to 28 may be the same as the respective combinations associated with values ​​29 to 56, respectively. The remaining values ​​57-63 may be used for other purposes, or alternatively, may be used to provide a larger number of selectable combinations.

[0113] In the following, the value indicated by the precoding information field is denoted by 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 L,TPMI mod 29. Therefore, I L,TPMI =0 and I L,TPMI =29 indicates that the assigned transmission uses 2 layers and TPMI=0. L,TPMI =17 and I L,TPMIFor a subframe with one codeword enabled and one codeword disabled, I = 46 indicates that 3 layers and TPMI = 1 are used in the assigned transmission. 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 further 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 given specification or configurable by semi-static signaling so that the combination that is optimal for the particular channel conditions can be selected for each terminal and in accordance with the timing.

[0114] In a specific example of the case of two antenna ports, for two enabled codewords, the number of layers and the TPMI are determined by searching for "I" in the "Bit Field Mapped to Index" column according to the table of FIG. 7A. L,TPMI mod 1. Therefore, I L,TPMI = {0,1,2,3,4,5,6,7} all indicate that 2 layers and TPMI = 0 are used in the assigned transmission (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 number of layers is used in the assigned transmission, and so on. The first combination, the second combination, and the other combination (if applicable) are preferably selected from the set of combinations available for one disabled codeword in the case of single subframe scheduling, for example 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 the specific channel conditions can be selected per 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 (eight in this particular example) combinations, and thus can indicate all six combinations defined without needing to be semi-statically configurable.

[0115] According to a fifth example, the DCI conveying 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). In this example, it is assumed that the channel conditions, and thus the appropriate combination of TPMI and number of layers, do not change substantially over time (this can be safely assumed at least for terminals that are not very mobile).

[0116] According to the sixth example, a certain 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. Thus, the subframes in which both codewords are enabled utilize this signaled combination. The subframes in which only one of the two codewords is enabled apply the combination obtained according to the certain mapping of the combination signaled for both enabled codewords to the applicable combination for one enabled codeword.

[0117] In the examples so far, codewords can be disabled or enabled on a subframe basis. Moreover, precoding information is signaled separately for different numbers of enabled codewords, which is advantageous. The examples so far have been 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 a multi-subframe allocation with MIMO with precoding that allows the mapping of more than one codeword to one subframe. In such a system, one or more codewords can be disabled on a subframe basis by using a modulation and coding scheme indicator value that is not associated with a particular MCS, possibly in combination with a particular value of another signaled parameter such as the redundancy version. Correspondingly, precoding information for each such configuration (one codeword disabled, two codewords disabled, three codewords disabled, etc.) can be signaled. Such signaling can be provided, 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, according to the examples described above.

[0118] Alternatively, the information of whether one codeword is disabled or two codewords are enabled is conveyed by the precoding information field. This alternative method is applicable to single subframe scheduling as well as multi-subframe scheduling, where the enabling or disabling of a codeword is applied to all subframes scheduled by the corresponding DCI. A first set of precoding information values ​​implicitly indicates that one codeword is disabled, and a second set of precoding information values ​​implicitly indicates 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 interpretations in the two right columns. Thus, there are seven values ​​in total, i.e., the size of the precoding information field of 3 bits can be maintained. The values ​​indicated by the precoding information field can be expressed as I, I, and I, and the second set can be expressed as 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 7 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. Thus, there are 69 values ​​in total, i.e., the size of the precoding information field is 7 bits. Let the value indicated by the precoding information field be 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 expressed 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., 69-64=5 combinations need to be removed compared to the full set of combinations. Such subsampling can be applied, for example, as described above in relation to the first example.

[0121] Furthermore, the present disclosure provides an apparatus 810 for receiving resource grants for multiple subframes in a communication system 800. Such an apparatus can be any kind of mobile station (User Equipment: UE), such as a mobile phone, a smartphone, a USB adapter, a computer, a tablet, a laptop, a wearable device (e.g., a smart watch or smart glasses), etc. The communication system is advantageously an LTE system or an LTE-A system. However, the present invention is not limited to an LTE system. Instead, any 4G or 5G system, or even any system such as WiFi, WiMax, etc., that employs multiple antennas and corresponding signaling, 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 a possible uplink transmission process (Figure 9A) and a possible downlink transmission process (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, and mappers of 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 resources for transmission 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 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 a number of values, including a value indicating one of the MCSs and at least one value that does not indicate any MCS. The MCS indicator can be a field with a predefined bit length capable of representing a set of values. Some of the values ​​are associated with a particular respective modulation (more specifically, the modulation order in case the modulation type is the same) and with the size of the transport block(s) that is mapped to the allocated resources (depending on the coding applied). Some of the values ​​are not associated with coding or modulation. The latter values ​​can be used for another purpose 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 the plurality of codewords in the plurality of subframes is disabled if the MCS indicator for at least one of the plurality of codewords has a value not indicating MCS, and is not disabled otherwise. This does not necessarily mean that an MCS indicator not indicating MCS always means disabled. In an embodiment, an MCS indicator not indicating MCS always means disabled. In another embodiment, an MCS indicator not indicating MCS can only indicate disabled 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, or 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 may further extract a specific field of the control information carrying a configuration value. As explained above, the signal 855 may correspond to a downlink signal transmitted from an eNB to a terminal in a current LTE system or an LTE-A system, the control information may correspond to a DCI, the MCS indicator may correspond to an MCS field, and the precoding information may correspond to a combination of a TPMI and a number of layers.

[0127] In one embodiment, the plurality of values ​​includes 32 values ​​indexed according to the PUSCH MCS table applied in LTE, among which the three values ​​with the highest indexes do not indicate an MCS and can be used to indicate the deactivation of codewords for several subframes. In particular, the 32 values ​​can be given 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, among the 32 values, a predefined or preconfigured number of values ​​can be associated with a specific respective 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, since it allows the reuse of the MCS table already defined in LTE. However, the invention is not limited by this example, and the number of values ​​can be larger or smaller depending on the number of bits provided for the signaling of the MCS in the control information. As an advantage of this method in the LTE example, the number of configurable MCSs is not further reduced, but rather a value indicating a redundancy version is utilized. If the RV is signaled separately for each subframe as illustrated in FIG. 6, the RV value is no longer necessary.

[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, which 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 disabled if the MCS indicator for at least one of the plurality of codewords has a value not indicating an MCS and the redundancy version indication information has a first predefined value. Otherwise, i.e. if the MCS indicator takes a value indicating a certain MCS among the plurality of configurable MCSs and is combined with another value of the redundancy version indication information signaled per subframe and indicating one of the configurable redundancy versions, the codeword or codewords are not disabled. As will be clear 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 legacy DCI, or may be any other length for systems requiring more redundancy versions.

[0130] As explained above, in a subframe where 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 to 28 in the above example relating to LTE, and such a value 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 the subframes for which the control information indicates an allocation (grant). The precoding indication information field may indicate the TPMI and / or the number of layers. Note that in the above example, the precoding information field indicated this combination of TPMI and the number of layers 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 number of layers may generally be signaled by another field, or may be implicitly indicated, or may be signaled in another layer. Meanwhile, the precoding information may signal further configurations.

[0133] In one embodiment, the precoding information indicates a combination of a transmit precoding matrix indication (TPMI) and the number of transmission layers. This 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 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 set of candidates preconfigured by semi-static signaling. In particular, an RRC message from the base station to the terminal may configure a set of candidates of indices associated with each combination of TPMI and layer number. Advantageously, the number of combinations in the set of candidates is smaller than all possible combinations and / or all configurable configurations. The set of candidates may be selected, for example, based on 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 that allows signaling of only values ​​in the set of preconfigured candidates. For example, if there are 32 combinations generally possible, the precoding information requires 5 bits to signal them. However, the set of candidates may include only four candidate combinations preconfigured by RRC, in which case only 2 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 out of multiple predefined combinations of TPMI and number of transmission layers that are also selectable in the case of a single-layer configuration using one codeword per subframe, or out of 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 the respective 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 of 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] Also shown in Fig. 8 is 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 not indicating 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 a transmission configuration for another apparatus and provides the selected configuration to the other apparatus via control information. The configuration may include, for example, physical layer parameters such as modulation and coding configuration, MIMO configuration such as number of layers and precoding matrix, resource allocation, HARQ configuration, 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 for each subframe, precoding indication 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 separate for each of the plurality of codewords.

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

[0142] Further, a communication system is also provided as shown in Fig. 8, 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 partly a wireless channel. The system may be part of a communication system, which may for example be LTE, LTE-A, further developments of LTE (such as LAA) or any other system comprising wireless links.

[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 the 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, so 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 indicating 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, which can be done by a bit where the bit is set to 0 to indicate that one codeword is disabled and set to 1 to indicate 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 or two codewords, assuming there is a maximum number of codewords equal to 2. The bitmap can therefore have a length of, for example, 2, 3, 4, or 5 or more bits (typically 10 or less), depending on the configured number of subframes (in a plurality of subframes) for which one scheduling message is provided.

[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 enabling / disabling of a larger number of codewords. For a larger number of codewords, it is assumed that one MCS field is included in the DCI for each codeword.

[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 the two-codeword transmission (when both codewords are enabled) and one-codeword transmission (when only one codeword is enabled). In other words, if a two-codeword transmission is indicated by the codeword enable / disable field for a subframe, an MCS with index values ​​from 0 to 28 is applied to both codewords in that subframe, and if a one-codeword transmission is indicated by the codeword enable / disable field for a subframe, 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, a field indicating whether codewords in a particular subframe are enabled or disabled can indicate the number and / or identity of the disabled codewords. Alternatively, the 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 a field that is n bits long.

[0151] In another example, for each subframe, a 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 would require a total of exp(3,n) states for n subframes, which can be represented by a field that is Ceil{log2(exp(3,n))} bits long.

[0152] In another example, for each subframe, a 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 would require a total of exp(4,n) states for n subframes, which can be represented by a field 2n bits long.

[0153] Concerning 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 for the case of setting one codeword transmission and the case of setting 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, which indicates the precoding information for a two-layer configuration where both codewords are enabled. In this case, this precoding information applies to subframes where 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 where 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 selection between three possible configurations (combinations of TPMI and number of layers). When MCS2 is equal to 29 to 31, there is a selection between three further configurations. Thus, the base station can dynamically select between six precoding configurations for the one codeword case. The six possible values ​​can also indicate a combination of TPMI and number of layers as explained above. However, the invention is not limited thereto, and the precoding information may convey only precoding matrix indication information. The number of layers can be indicated in another way.

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

[0157] It should be noted that the above-described configuration of precoding information based on MCS field values ​​that do not indicate MCS is not available only in cases where the enabling / disabling of codewords per subframe is explicitly signaled. Instead, MCS field values ​​that are not used for signaling MCS (or 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. It should be noted that, looking at the MCS table in FIG. 5, MCS field values ​​29, 30, and 31 can also be defined as values ​​that are not used for signaling 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 according to 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, the 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 that can be configured for transmission, it may be advantageous to also include the number of the codewords to be disabled or the number of the codewords to be enabled in the codeword indication information. In some systems, it may be advantageous to signal only the number of the codewords to be disabled or the number of the codewords to be enabled and assume that the codeword to be disabled is the codeword with the highest index.

[0161] Furthermore, in this embodiment, it is advantageous that the control information further comprises a Modulation and Coding Scheme (MCS) indicator common to the grant 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 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 in accordance with the MCS indicator taking a value indicative of one of the MCSs.

[0162] The processing device may be configured to determine the precoding configuration based on an MCS indicator having a value not indicating 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 not indicating 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, corresponding to the control information receiving apparatus 810, an apparatus 850 for transmitting resource grants for a number of subframes in a communication system is provided.

[0164] The apparatus 850 comprises a processing device configured to select, for each subframe, whether a codeword from the 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 enabling or disabling of one or more codewords in each of the plurality of subframes.

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

[0166] FIG. 10 illustrates an exemplary method according to the present disclosure. In particular, 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 the purposes of the present invention, the manner in which the DCI is received is not important. Reception of the DCI may be by monitoring the 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 a number of subframes and a number of codewords for each subframe, and a Modulation and Coding Scheme (MCS) indicator common to the number of subframes granted and individual for each of the number of codewords, the MCS indicator taking one of a number of values ​​including a value indicating one of the number of MCSs and at least one value not indicating an MCS. Correspondingly, the method may further include a step of retrieving a resource grant (resource allocation (RA)) for the number of subframes from the DCI (1030) and a step of retrieving an MCS indicator for each of the number of codewords (1040). Then, an MCS value for the first codeword is evaluated (1050). If the MCS belongs to an interval of values ​​that is not assigned to any MCS (even in the legacy single subframe allocation) (yes in step 1050), in step 1060, the codeword may be directly set as disabled in the scheduled transmission. However, according to another embodiment, further parameter(s) are checked in step 1060 in order to decide whether the codeword is disabled or not. The same evaluation is performed for the second (or subsequent) codeword. The check may include evaluation of the RV value signaled on a subframe-by-subframe basis, which allows the activation / deactivation to be controlled on a further subframe-by-subframe basis. In other words, step 1060 is a step of determining that the codewords in the subframes are disabled if the MCS indicator for at least one of the codewords has a value not indicating MCS (yes in step 1050) and are not disabled otherwise (no in step 1050). In step 1070, the scheduled data transmission is performed. In particular, the transmission over the subframes is performed in the assigned (granted) resources using the configured MCS for the enabled codeword.

[0168] The step of evaluating the MCS value and the 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 of all subframes. Specifically, there may be a precoding indication information field indicating the TPMI and number of layers for both enabled codewords if both codewords are enabled, and indicating the TPMI and number of layers for one enabled codeword if only one codeword is enabled. If the codewords are enabled or disabled on a subframe basis, the method may include retrieving a first precoding indication information for the subframes where both codewords are enabled and a second precoding indication information if only one codeword is enabled. These indication information 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 (signaling a combination of TPMI and number of layers). However, for the purpose of conveying the control information more efficiently, preferably only one precoding information field may be taken from the DCI, 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 are mutually independent of the first range of values). Further alternative methods for determining the precoding indication information for a subframe in the case of one or both codewords are described above in relation to the signal structure and the corresponding devices.

[0170] Fig. 10 further illustrates a transmission method that may be performed in a scheduling entity, such as a network node, a base station, an access point, or another terminal performing a scheduling function. The method may include a step of generating control information (1000). This step includes a step of setting a modulation and coding scheme (MCS) indicator to a value not indicating MCS, in order to indicate that a codeword from a plurality of codewords in a plurality of subframes is nullified. Then, control information including such MCS field value and further parameters that may also be set is transmitted to the UE in a transmission signal (1010). The transmitted control information includes, in particular, a resource grant for a plurality of subframes and a plurality of codewords in each subframe, and an MCS indicator that is common to the plurality of subframes granted and individual to each of the plurality of codewords, the MCS indicator taking one of a plurality of values ​​including a value indicating one of a plurality of MCSs and at least one value not indicating MCS. The control information may also include precoding indication information common to a plurality of subframes, as explained above. In step 1090, data is received (and retrieved from resources) according to the control information.

[0171] FIG. 11 illustrates another embodiment of a method according to the present disclosure. The method of receiving resource grants for a plurality of subframes in a communication system includes receiving a signal including control information (1120). 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 activation or deactivation of one or more codewords in each of the plurality of subframes. Thus, the resource grant is retrieved in step 1130, and the codeword indication information (CWI) is retrieved in step 1140, whereby for each subframe, it is determined whether and / or which codewords from the plurality of codewords in that subframe are enabled or disabled according to the codeword indication information. Then, data is transmitted (1170) using the configuration received in the control information in step 1120, i.e., in the granted resources in the plurality of subframes and with the codewords enabled / disabled on a subframe-by-subframe basis according to the retrieved codeword indication information (CWI).

[0172] 11, a method of transmitting resource grants for a plurality of 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 a signal (1110) including 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 enabling or disabling of one or more codewords in each of the plurality of 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 stated, it should be understood that without loss of generality, 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. It should be noted 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 above concepts can also be directly applied to the activation / deactivation of transport blocks.

[0175] In LTE / LTE-A, when only codeword 0 is enabled, there is still a choice whether transport block 1 or transport block 2 is mapped to codeword 0, which is especially relevant when disabling a codeword to improve retransmission of a previously transmitted transport block. The mapping of transport blocks to codewords is specified in table 5.3.3.1.5-2 of 3GPP TS 2013-01-13344 (corresponding to 3GPP TS 2013-01-13344) for the case when only one codeword (and therefore only one of the two transport blocks) is enabled: [Table 1]

[0176] In such a case, the embodiments and examples presented herein determine which transport block (1 or 2) is enabled and which transport block is disabled (2 or 1), and the corresponding enabled transport block is mapped to codeword 0 accordingly. For example, according to the embodiment using the MCS field value described above to enable / disable codeword(s), 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. On the other hand, 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 clear to those skilled in the art, this LTE mapping is an option. However, there may be other rules for mapping between transport blocks and codewords. 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 a plurality of subframes and a plurality of codewords in each subframe; precoding indication information common to the plurality of subframes; and control information comprising 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 not indicative of MCS; and a processing device configured to determine that a codeword from a 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 not indicative of MCS, and to determine not to be disabled otherwise.

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

[0179] For example, the control information further comprises redundancy version indication information, individual for each of the plurality of subframes and common to all codewords in the respective subframe, and the processing device is configured to determine that a codeword from the plurality of codewords in the plurality of subframes is 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 to determine that a codeword from the plurality of codewords in the plurality of subframes is not 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 is not indicative of the 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 particular value indicative of the MCS, where the particular value is not used together with the redundancy version indication information to indicate the disablement 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 the TPMI and the number of transmission layers among a plurality of predefined combinations of the TPMI and the number of transmission layers, or indicates a combination of the TPMI and the number of transmission layers among a plurality of combinations of the TPMI and the number of transmission layers in a set of candidates predefined by semi-static signaling, or indicates a combination of the TPMI and the number of transmission layers among a plurality of predefined combinations of the 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 among a plurality of predefined combinations of the 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 the respective combination of the 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 of 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 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 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 an 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 not indicating one of the multiple MCSs, or to determine which codewords are disabled based on an MCS indicator having a value not indicating 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, in particular an apparatus for transmitting resource grants 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 resource grants for a plurality of subframes and a plurality of codewords in each subframe, control information including precoding indication information common to the plurality of subframes, and an MCS indicator common to the plurality of subframes 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 not indicative of MCS.

[0188] Further provided is an apparatus for transmitting a resource grant 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 of each subframe, and codeword indication information indicating 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: 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 control information including 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 not indicative of 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 not indicative of MCS, and determining not to disable otherwise.

[0191] Further provided is a method for receiving a resource grant for a plurality of subframes in a communication system, the method comprising: receiving 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 determining 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.

[0192] Further provided is a corresponding transmission method, in particular a method of transmitting resource grants for a plurality of subframes in a communication system, comprising the steps of: 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 the resource grants for the plurality of subframes and a plurality of codewords in each subframe, and control information including precoding indication information common to the plurality of subframes, and an MCS indicator common to the plurality of subframes 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 the 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 of each subframe, and codeword indication information indicating 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, a (non-transitory) computer readable medium is provided having stored thereon a program which, when executed on a computer, performs the steps of the method described above.

[0196] [Hardware and Software Implementation 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 is further recognized that the various embodiments may be implemented or performed using a computing device (processor). The computing device or processor may be, for example, a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device. The various embodiments may also be implemented or embodied by a combination of these devices. In particular, each of the functional blocks used to describe each of the above embodiments may be implemented by an LSI, which is an integrated circuit. These functional blocks may be composed of individual chips, or may be composed of one chip to include some or all of the functional blocks. These chips may include data inputs and outputs coupled thereto. Depending on the degree of integration, the LSI may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI. However, the technology for implementing an integrated circuit is not limited to an LSI, and may be achieved by using a dedicated circuit or a general-purpose processor. Furthermore, an FPGA that can be programmed after LSI manufacturing, or a reconfigurable processor that allows reconfiguration of 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. Also, a combination of software modules and hardware implementation is 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 is to be noted that individual features of the different embodiments may be the subject of another embodiment, 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, and 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 of codewords in a multi-subframe grant. In particular, it allows dynamic and subframe-by-subframe enabling / disabling of codewords even if other control parameters, including resource allocation, are performed for multiple subframes. For example, a signal from a scheduling entity to a scheduled entity comprises 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. For each subframe, it is determined whether and / or which codewords from the multiple codewords in that subframe are enabled or disabled according to the codeword indication information. Alternatively, the indication of enabling and disabling can be done by using a modulation and coding scheme indicator value that is not associated with a particular modulation and coding scheme.

Claims

1. 1. A user equipment for receiving resource grants for a plurality of subframes in a communication system, the user equipment comprising: the resource grant for a number of subframes and a number 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 the grant subframes and is separate for each of the codewords of each subframe, the MCS indicator taking one of a number of values ​​including a value indicative of one of a number of MCSs and at least one value that does not indicate an MCS; a receiver for receiving a signal comprising control information including: a control unit, wherein when the plurality of codewords includes a first codeword and a second codeword, and a first MCS indicator has a value indicating one of the MCSs and a second MCS indicator has a value indicating no MCS, the first codeword or the second codeword is invalidated depending on whether a different redundancy version (RV) for each subframe indicates a first RV state or a second RV state; having User equipment.

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. The user equipment of claim 1 .

3. The precoding indication information indicates a combination of a transmission precoding matrix indication information (TPMI) and a number of transmission layers. The user equipment of claim 1 .

4. The combination of the TPMI and the number of transmission layers is A combination of TPMI and transmission layer number among a plurality of predefined combinations of TPMI and transmission layer number; The user equipment of claim 3.

5. The combination of the TPMI and the number of transmission layers is A combination of TPMI and transmission layer number among a plurality of combinations of TPMI and transmission layer number in a candidate set pre-configured by semi-static signaling. The user equipment 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 of a single-layer configuration. The user equipment of claim 3.

7. 1. A method performed by a user equipment for receiving resource grants for a plurality of subframes in a communication system, the method comprising: the resource grant for a number of subframes and a number 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 the grant subframes and is separate for each of the codewords of each subframe, the MCS indicator taking one of a number of values ​​including a value indicative of one of a number of MCSs and at least one value that does not indicate an MCS; receiving a signal comprising control information including: and when the plurality of codewords includes a first codeword and a second codeword, and a first MCS indicator has a value indicating one of the MCSs and a second MCS indicator has a value indicating no MCS, the first codeword or the second codeword is disabled depending on whether a different redundancy version (RV) for each subframe indicates a first RV state or a second RV state. method.

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