Integrated circuit

Abstract

To provide an integrated circuit and a communication system including a base station and a user device transmitting / receiving data using multiple antennas.SOLUTION: An integrated circuit for controlling processing in a base station comprises: circuitry 280 which transmits, to a user device, a parameter defining a rule for assigning, to ports, respective resources for carrying reference signals, and control information indicating one combination to be applied to data reception / transmission among a set of layer-to-port mapping combinations based on a mapping. The combinations are continuously indexed including both combinations using one symbol and combinations using two or more symbols. Among the combinations included in the set of layer-to-port mapping combinations, the combinations for two or more layers using two or more symbols include a combination having consecutive port numbers of which a port is duplicated in another combination for the same number of layers.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to the transmission and reception of data and / or reference signals in resources of a communication system. [Background technology]

[0002] Currently, the 3rd Generation Partnership Project (3GPP) is working on the next release (Release 15) of technical specifications for the next generation of cellular technology, also known as the fifth generation (5G). At 3GPP's Technical Specification Group (TSG) Radio Access network (RAN) meeting #71 (March 2016, Gothenburg), the first study item for 5G, "Study on New Radio Access Technology", involving RAN1, RAN2, RAN3, and RAN4, was approved and is expected to become a work item in Release 15 that will define the first standards for 5G.

[0003] One objective of 5G NR (New Radio) is to provide a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios defined in 3GPP Announcement No. 10-21511 (available at the 3GPP website (www.3gpp.org) and incorporated herein by reference in its entirety) and includes at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communication (mMTC). For example, deployment scenarios for eMBB may include indoor hotspots, dense urban areas, suburban, urban, and high-speed. Deployment scenarios for URLLC may include industrial control systems, mobile health management (remote monitoring, diagnosis, and treatment), real-time control of vehicles, and wide-area monitoring and control systems for smart grids. mMTC may include scenarios using a large number of devices with low-latency data transmission, such as smart wearables and sensor networks.

[0004] Another objective is forward compatibility: backward compatibility with Long Term Evolution (LTE) is not required, which facilitates the design of entirely new systems and / or the introduction of new features.

[0005] As summarized in one of the technical reports of the NR (New Radio) study items (Non-Patent Document 2), the basic signal waveform of the physical layer is based on Orthogonal Frequency Division Multiplexing (OFDM). In both the downlink and uplink, waveforms based on OFDM using cyclic prefix (CP-OFDM) are supported. At least in the uplink of eMBB up to 40 GHz, waveforms based on Discrete Fourier Transformation (DFT) spread OFDM (DFT-S-OFDM) are also supported as an adjunct to the CP-OFDM waveform.

[0006] One of the design goals in NR is to seek waveforms for downlink, uplink, and sidelink as common as possible. It is considered that in some cases of uplink transmission, it may not be necessary to introduce DFT spreading. The term "downlink" means communication from a higher-level node to a lower-level node (e.g., from a base station to a relay node, from a base station to a UE, from a relay node to a UE, etc.). The term "uplink" means communication from a lower-level node to a higher-level node (e.g., from a UE to a relay node, from a UE to a base station, from a relay node to a base station, etc.). The term "sidelink" means communication between nodes at the same level (e.g., between two UEs, between two relay nodes, or between two base stations).

[0007] The term "spatial layer (or layer)" refers to one of several different streams generated by spatial multiplexing. A layer can be described as a mapping of symbols to transmit antenna ports. Each layer is identified by a precoding vector of size equal to the number of transmit antenna ports and can be associated with a radiation pattern. The rank of a transmission is the number of layers transmitted. A codeword is an independently coded data block corresponding to one transport block (TB) passed from the transmitter's medium access control (MAC) layer to the physical layer and protected by a cyclic redundancy check (CRC). In general, a layer is assigned per transmission time interval (TTI), which corresponds to a subframe in LTE. However, in NR, different TTIs can be adopted depending on URLLC or eMBB. In particular, in NR, a TTI can be a slot, a minislot, or a subframe. For layers, ranks, and codewords, see also Section 11.2.2.2 of 3GPP TS 2013-01-13344 (incorporated herein by reference).

[0008] From an antenna port (or ports) at the base station, a reference signal pattern (RS) is transmitted. A port can be used for transmission as one physical transmit antenna or as a combination of multiple physical antenna elements. In either case, the signal transmitted from each antenna port is not designed to be further resolved by the UE's receiver. The transmitted reference signal pattern (RS) corresponding to a given antenna port defines the antenna port from the UE's perspective and allows the UE to derive a channel estimate for all data transmitted on that antenna port, regardless of whether the antenna port corresponds to one radio channel from one physical antenna or a composite channel from multiple physical antenna elements that together include the antenna port. For ports, see also Section 8.2 of Non-Patent Document 3, which is incorporated herein by reference.

[0009] In LTE, data transmission and reception at UEs is scheduled by the eNB using Physical Downlink Control Channels (PDCCHs), which carry messages known as Downlink Control Information (DCI), including resource allocations and other control information intended for a UE or a group of UEs. Typically, several PDCCHs can be transmitted within a subframe.

[0010] The required content of the control channel message depends on the system deployment and the UE configuration. For example, if the infrastructure does not support MIMO or the UE is configured in a transmission mode without MIMO, there is no need to signal parameters that are only required for MIMO transmission. Therefore, in order to minimize the signaling overhead, it is desirable to have several different message formats available, each containing the minimum payload required for a particular scenario. On the other hand, it is desirable not to specify too many formats to avoid overcomplicating the implementation and testing. Below, a set of formats of DCI messages specified in LTE is listed.

[0011] Please refer to the above-listed technical standards or to Section 9.3.5 of IEEE 802.11b, which is 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 very compact transmission of PDSCH assignments. When Format 1C is used, PDSCH transmissions are constrained to use QPSK modulation. This format is used, for example, to signal paging messages and 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 information transmitted is the same as in format 2, with the exception that there is no precoding information 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.

[0012] 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 blindly decoding and checking the CRC. The search spaces can be common and UE-specific search spaces. The UE needs to monitor both the common and UE-specific search spaces (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 commands (TPC-PUCCH / PUSCH-RNTI). The UE-specific search space carries DCI for UE-specific assignment (using the C-RNTI assigned to the UE), semi-persistent scheduling (SPS C-RNTI), or initial assignment (temporary C-RNTI).

[0013] Thus, the DCI specifies the resources on which the UE is to receive or transmit data (including transmission and reception configuration). [Prior art documents] [Non-patent literature]

[0014] [Non-Patent Document 1] 3GPP TSG RAN TR 38.913 v14.1.0, “Study on Scenarios and Requirements for Next Generation Access Technologies”, Dec. 2016 [Non-Patent Document 2] 3GPP TSG TR 38.801 v2.0.0, “Study on New Radio Access Technology; Radio Access Architecture and Interfaces”, March 2017 [Non-Patent Document 3] S. Sesia, I. Toufik and M, Baker, LTE: The UMTS Long Term Evolution, Second Edition [Non-Patent Document 4] LTE - The UMTS Long Term Evolution - From Theory to Practice, Edited by Stefanie Sesia, Issam Toufik, Matthew Baker [Non-Patent Document 5] 3GPP TSG RAN Meeting #75, RP-171485 by NTT DoCoMo, “Revised WID on New Radio Access Technology”, June 5-8, 2017 [Non-Patent Document 6] RAN1 Chairman Notes: RAN1 NR Ad-Hoc#2 [Non-Patent Document 7] 3GPP TSG RAN WG1 Meeting NR Ad-Hoc#2, R1-1711784 Agenda item: 5.1.2.4.3, MediaTek et al., “WF on DMRS Design”, Qingdao, China, 27 - 30 June 27 - 30, 2017 [Non-Patent Document 8] 3GPP TSG RAN WG1 Meeting NR Ad-Hoc#2 R1-1711771, Agenda Item:5.1.2.4.3, LG Electronics, ZTE, “WF on signaling DMRS configuration”, Qingdao, China, 27 - 30 June 27 - 30, 2017 [Non-Patent Document 9] 3GPP TS 36.212, V14.3.0 Summary of the Invention

[0015] A non-limiting, exemplary embodiment facilitates flexible mapping of layers to ports and flexible configuration of 1-symbol or 2-symbol DMRS in multiple different front-loaded DMRS configurations while maintaining reasonable signaling overhead.

[0016] In one general aspect, the techniques disclosed herein provide a user equipment in a communications system for transmitting data to and / or receiving data from a base station using multiple antennas, the user equipment comprising circuitry that, in operation, receives parameters defining rules for allocating respective resources to ports for carrying reference signals, generates a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station, and receives control information from the base station indicating one combination of the set of layer-to-port mapping combinations to be applied for transmitting and / or receiving data.

[0017] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof.

[0018] 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 through the various embodiments and features of the specification and drawings, although it is not necessary for all of these features to be present in order to obtain one or more of such benefits and / or advantages. [Brief description of the drawings]

[0019] [Figure 1] 1A to 1D are schematic diagrams of configuration types of forward mapped demodulation reference signals (DMRS). [Diagram 2] FIG. 2 is a block diagram showing the structure of a transmitting device and a receiving device. [Diagram 3] FIG. 3 is a block diagram showing a framework for DMRS port indexing, mapping of layers to ports, and indicating 1-symbol or 2-symbol DMRS. [Figure 4] 4A and 4B are diagrams of example port numbering for an example one-symbol DMRS configuration type. [Diagram 5] 5A and 5B are diagrams of example port numbering for an example two-symbol DMRS configuration type. [Figure 6] FIG. 6 is a block diagram showing the circuitry of the user equipment. [Figure 7] FIG. 7 is a diagram showing a downlink demodulation reference signal (DMRS) using eight orthogonal ports. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In the 3rd Generation Partnership Project New Radio (3GPP NR), reference signals are being redesigned to meet a wide range of requirements and use cases. Demodulation Reference Signals (DMRSs) used for channel estimation purposes are also being designed to have a uniform structure in both uplink and downlink using Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) waveforms. This disclosure relates to port mapping of forward-placed DMRS (at the beginning of a data channel) and related signaling aspects. It has already been agreed that two configurations of forward-placed DMRS (with different multiplexing schemes of orthogonal DMRS ports) are supported, and that each configuration has the flexibility to use 1-symbol DMRS or 2-symbol DMRS. In current LTE, there is a fixed configuration with one type of multiplexing scheme of orthogonal DMRS ports, which allows a rather inflexible mapping of layers to ports. However, in NR, it is expected to have a flexible mapping of layers to ports to take advantage of multiple different multiplexing schemes of orthogonal DMRS ports. This disclosure provides a framework on how to flexibly set port indexing, generate a mapping of layers to ports, and indicate the 1-symbol or 2-symbol DMRS in each configuration together with the index of the table.

[0021] This disclosure relates to NR technology. For ongoing work items on NR access technology, see 3GPP TS 2013-01-1321 (http: / / www.rfc2013-01-1321). More specifically, this disclosure addresses aspects of forward-located DMRS in both downlink and uplink using CP-OFDM waveforms. The chairman notes from RAN1 NR#2 (3GPP TS 2013-01-1321 (incorporated herein by reference)) document all the latest agreements related to DMRS, and this disclosure addresses some of the aspects that have not yet been considered or are open to further consideration. This disclosure provides a framework for flexible mapping of layers to DMRS ports and signaling of 1-symbol or 2-symbol DMRS in forward-located DMRS configurations, respectively.

[0022] As mentioned above, in 3GPP NR, the demodulation reference signal (DMRS) is redesigned in both the downlink and uplink.

[0023] According to the latest agreement, two configurations of forward placed DMRS are supported in the downlink and uplink using CP-OFDM waveforms, which are shown in Figures 1A-1D. The forward placed reference signal is assigned to the first data symbol adjacent to the signaling section of the TTI (the signaling section consists of, for example, two symbols) when one-symbol DMRS is used, and to the first two data symbols when two-symbol DMRS is used. In particular, the following relevant agreements related to NR DMRS are proposed in 3GPP TS 2011-01-01 14:23 Page 2 of 11 (incorporated herein by reference) and are updated and agreed upon in the Chair's Memo (available at the 3GPP website (www.3gpp.org)) (incorporated herein by reference):

[0024] The assumptions made in RAN1#89 regarding DM-RS are updated and agreed upon for the CP-OFDM case as follows: UE is configured by higher layers to use DMRS patterns from forward-located DMRS configuration type 1 or DMRS patterns from forward-located DMRS configuration type 2 in downlink / uplink.

[0025] Each of Figures 1A-1D shows an exemplary grid corresponding to a slot of 14 symbols and 12 subcarriers. The first two symbols on the left side of each figure correspond to the signaling section of the slot. In the signaling section, the Physical Downlink Control Channel (PDCCH) is signaled. In LTE, a subframe always contains two slots. However, in a typical communication system, a subframe may correspond to one slot or may contain more than two slots. Furthermore, the present disclosure is not limited to slots having 14 symbols and 12 subcarriers.

[0026] 1A and 1B show a first forward-located DMRS configuration corresponding to configuration type 1. This configuration is intended to support up to eight orthogonal ports for Single-User Multiple Input Multiple Output (SU-MIMO) or Multi-User Multiple Input Multiple Output (MU-MIMO). This first configuration supports up to four orthogonal ports when one-symbol DMRS is used as shown in FIG. 1A. Specifically, two combs and two cyclic shifts (CS) can be combined to form up to four component sets, and each resulting component set can be assigned to up to four ports, respectively. If a two-symbol DMRS is used as shown in Figure 1B, the two combs and two cyclic shifts can be further combined with two time division Orthogonal Cover Codes (TD-OCC), specifically Walsh-Hadamard TD-OCC ({1,1} and {1,-1}), to support up to eight orthogonal ports. However, in the case of a two-symbol DMRS, it should also be possible to schedule up to four ports without using both {1,1} and {1,-1}.

[0027] A second forward-distributed DMRS configuration corresponding to configuration type 2 is shown in FIG. 1C and FIG. 1D. This configuration provides support for up to 12 orthogonal ports for SU-MIMO or MU-MIMO. In particular, six component sets are formed by two (Walsh-Hadamard) Frequency Division Orthogonal Cover Codes (FD-OCCs) respectively applied across adjacent REs in the frequency domain. As can be seen from FIG. 1C and FIG. 1D, for 12 subcarriers, adjacent RE pairs are grouped into three Frequency Division Multiplexing (FDM) groups. Thus, six component sets are formed from two FD-OCCs (both {1,1} and {1,-1}) respectively applied to the three FDM groups. For the one-symbol DMRS case (FIG. 1C), each of the six resulting component sets can be assigned to up to six orthogonal ports. In the case of two-symbol DMRS, these six component sets can be further combined with two TD-OCCs, resulting in support of up to 12 orthogonal ports (FIG. 1D).

[0028] As described above with reference to Figures 1A-1D, the comb, cyclic shift, FD-OCC, FDM, and TD-OCC constitute the resource components of the reference signal (particularly, forward placed DMRS). These resource components are combined according to a first forward placed DMRS configuration or a second forward placed DMRS configuration, and the resulting component sets are assigned to orthogonal ports, respectively. However, the use of 2-symbol DMRS should also be possible for the low rank case. Only a part of the component set supported by a particular configuration in the 1-symbol DMRS or 2-symbol DMRS case needs to be used for port assignment. In particular, it should also be possible to schedule up to 6 ports in the 2-symbol case without using both {1,1} and {1,-1}.

[0029] From a user equipment (UE) perspective, DMRS ports that are multiplexed by frequency domain code division multiplexing (CDM) are quasi co-located.

[0030] Whether the forward-located DMRS configuration type for the UE can be different for uplink and downlink remains to be further explored. Furthermore, if there are significant complexity / performance issues with the above agreement, reduced options may be considered.

[0031] Furthermore, the following agreements have also been made in relation to the use of 2-symbol DMRS for low rank (see 3GPP TS 803.1102, 2011, incorporated herein by reference): When the number of DMRS ports assigned to a UE is equal to or smaller than N (N is 4 for configuration 1 and 6 for configuration 2), the number of forward positioned DMRS symbols can be 1 or 2. The details of the decision whether 1-symbol or 2-symbol DMRS is used remains to be further explored.

[0032] [Current LTE DMRS configuration] The above-mentioned DMRS configuration in NR is different from LTE, where there is primarily one configuration in the downlink shown in Figure 7 (using code division multiplexing in frequency and time with Walsh-Hadamard orthogonal cover codes) to support up to a total of eight orthogonal ports / layers. Further details regarding the configuration in Figure 7 and the DMRS configuration in LTE are provided in Section 29.1.1 of 3GPP TS 2013-01016, which is incorporated herein by reference.

[0033] The following Table 1 shows a table of layer to port mapping in current LTE (taken from Non-Patent Document 9 (Table 5.3.3.1.5C-2)). [Table 1]

[0034] Current LTE supports up to eight orthogonal DMRS ports in the downlink, which mainly use one type of multiplexing scheme (i.e., OCC in time / frequency). Therefore, any combination of ports can be used to map layers without affecting the performance in a given scenario. Furthermore, for a given number of layers, the resource usage (DMRS overhead) is the same for any combination of ports.

[0035] Additionally, current LTE provides limited support for MU-MIMO and supports fixed DMRS configurations, so no additional signaling is required for dynamic configuration.

[0036] Moreover, as can be seen from Table 1, the combinations allowed for layer to port mapping are very limited. In current LTE, a bitmap of length 4 is defined to signal the layer to port mapping for a given user, i.e. a minimum number of port combinations are supported in the layer to port mapping. In particular, for up to 2 layers, the indexing of ports for mapping is consecutive and non-overlapping. For 3-8 layers, the indexing is consecutive and non-overlapping, starting from index 0 as a fixed starting point. The mapping is limited to one combination of ports.

[0037] [DMRS requirements for NR] In NR, such support is not sufficient due to the challenges explained in the next paragraph. As per our knowledge, mainly because the current agreements are quite recent, there is no solution available other than specifically addressing the issues related to DMRS port mapping and related signaling in NR.

[0038] In NR, DMRS configurations are required to support a wide range of scenarios, including uplink, downlink, various carrier frequencies, and low latency, among others. The mapping of a user's layers to orthogonal DMRS ports is expected to be flexible for the following reasons: First, different ports may correspond to different types of multiplexing schemes whose operating performance may vary in different scenarios. Second, if the mapping of layers to ports is done in different ways, the resource usage (DMRS overhead) at a given number of layers may be different. Third, improved support for MU-MIMO is expected compared to the current support for MU-MIMO in LTE (Long Term Evolution). It is expected to flexibly configure 1-symbol DMRS or 2-symbol DMRS in each forward-placed DMRS configuration.

[0039] To support flexible mapping of layers to ports in various scenarios, more port combinations need to be allowed, resulting in increased signaling overhead. Furthermore, selecting either 1-symbol DMRS or 2-symbol DMRS in a given forward placed DMRS configuration type further increases the signaling overhead.

[0040] Based on these requirements, there is a need to support flexible mapping of layers to ports and flexible configuration of 1-symbol DMRS or 2+symbol DMRS in multiple different forward-located DMRS configurations while allowing for reasonable signaling overhead.

[0041] [Description of the embodiment] The present disclosure facilitates supporting flexible mapping of layers to ports and flexible configuration of one-symbol DMRS or more than one-symbol DMRS in multiple different forward-placed DMRS configurations while allowing for modest signaling overhead.

[0042] In an exemplary embodiment, as shown in FIG. 2, the present disclosure provides a user device 210 in a communication system, which transmits data to and / or receives data from a base station 260 using multiple antennas. The user device may correspond to a user equipment (UE) as it is commonly called in LTE and NR. The transmission and / or reception is typically performed using a radio channel. The user device includes a circuit 230 configured to receive parameters used to allocate resources for reference signals to ports, generate a set of layer-to-port mapping combinations, and receive control information from the base station 260 indicating one of the mapping combinations to be applied to the transmission and / or reception of data.

[0043] In particular, in operation, the circuit 230 receives parameters defining rules for allocating respective resources to ports for carrying reference signals. The resources allocated to the ports typically include at least two resource components. For example, these resource components correspond to comb, cyclic shift, FD-OCC, and FDM according to the respective configurations shown in Figures 1A-1D.

[0044] In operation, the circuitry 230 of the user equipment 210 generates a set of layer-to-port mapping combinations based on mappings known to the user equipment 210 and the base station 260. In this case, the layer-to-port mapping combinations specify, for each TTI, how the layers used to transmit or receive data by a particular user terminal, such as the user equipment 210, are mapped to the ports available in a given port configuration.

[0045] Furthermore, in operation, the circuitry 230 of the user equipment 210 receives control information from the base station 260 indicating one particular combination of layer-to-port mappings to be applied for data transmission and / or reception per TTI among a set of layer-to-port mapping combinations. That is, the indicated combination of layer-to-port mappings defines the ports to which the layers used by the user equipment 210 for data transmission and / or reception are mapped. In this case, the TTI may be, for example, a slot, a minislot, or a subframe.

[0046] Control information indicating one combination of layer-to-port mapping can be transmitted, for example, in a DCI in the PDCCH and can be part of a scheduling configuration that informs the terminal to apply that particular combination of layer-to-port mapping for data transmission and / or reception. The DCI can generally serve to schedule uplink or downlink data transmission (although generally both are also possible). Upon receiving the DCI, the UE configures layers and ports according to the received combination of layer-to-port mapping and receives or transmits data in the scheduled resources accordingly.

[0047] 2, the user equipment 210 includes a transceiver 220 (i.e., a transmitter for transmitting and a receiver for receiving radio waves over a wireless channel) that, in operation, applies an indicated combination of layer-to-port mappings as dictated by control information received from a base station to transmit and / or receive data.

[0048] The structure of the circuit 230 of the user equipment 210 is shown in Fig. 6. The circuit 230 of the user equipment comprises a signaling information receiving unit 232 and a mapping generating unit 231. The signaling information receiving unit 232 is configured to receive parameters defining rules for allocating respective resources for carrying reference signals to ports. The mapping generating unit 231 is configured to generate a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station. The signaling information receiving unit 232 is further configured to receive control information from the base station 260 indicating one of the set of layer-to-port mapping combinations to be applied for data transmission and / or reception. It should be noted that the transceiver 220 of the user equipment 210 receives radio waves transmitted by the base station 260 through a radio channel. The circuit 230 of the user equipment receives already demodulated data and / or control data from lower layers.

[0049] Corresponding to the user equipment 210, the present disclosure further provides a base station 260 for receiving data from and / or transmitting data to the user equipment in a communication system. The base station can be, for example, an eNodeB (eNB) or a similar entity in NR (currently referred to as gNB). Furthermore, the present disclosure is also applicable to a relay node (either a relay node treated as a base station as described herein or a relay node treated as a user equipment as described herein). The base station 260 (or more specifically, a transceiver 270 included in the base station 260) comprises multiple antennas, which in operation transmit or receive data. Furthermore, the base station 260 comprises a circuit 280, which in operation transmits parameters via the transceiver 270, defining a rule for allocating respective resources for carrying reference signals to ports. Furthermore, the circuit 280 of the base station 260 in operation generates a set of combinations of mappings of layers to ports based on mappings known to the user equipment and the base station. Thus, the base station can perform scheduling of the UE, i.e., assign resources to the UE for transmission or reception and provide the UE with corresponding configurations to be applied to transmission and reception parameters (such as modulation, coding, layer and port configurations as described above with respect to the DCI). The base station can perform scheduling for one or more UEs. In addition, the circuit 280 of the base station 260, in operation, transmits control information via the transceiver 270 indicating one combination of a set of layer-to-port mapping combinations to be applied by the user equipment 210 for data reception and / or transmission. The control information can be similar to DCI. After transmitting the control information for scheduling the transmission of data to the UE in the downlink, the base station transmits data in the downlink in the assigned resources using the port and layer combination.After transmitting control information scheduling the UE's data transmission on the uplink, the base station receives data from the UE on the uplink using a combination of layer-to-port mapping on the allocated resources.

[0050] As shown in Fig. 2, the base station 260 includes a transceiver 270 (i.e., a transmitter for transmitting radio waves over a wireless channel and a receiver for receiving radio waves over a wireless channel). In operation, the transceiver 270 performs reception of data transmitted by the user equipment 210 (applying an indicated combination of layer-to-port mappings as dictated by control information received from the base station) and / or transmission of data. The transceiver 270 includes multiple antennas of the base station.

[0051] For example, the circuit 280 of the base station 260 further configures parameters defining rules for allocating respective resources for carrying reference signals to ports, for example, the base station 260 uses the circuit 280 to configure parameters defining rules for port allocation and transmits the parameters to multiple user devices.

[0052] Furthermore, the circuit 280 of, for example, the base station 260 can further configure the control information applied to the user equipment 210 or the plurality of user equipments according to the layer number of each of the user equipment 210 or the plurality of user equipments. Thus, the base station, for example, sends the respective control information to each user equipment.

[0053] The rules for allocating the respective resources for the reference signals to the ports (port allocation rules) further define, for example, the port indexing (specifically the port indexing / numbering sequence), i.e. for each port (and thus for a particular set of resource components allocated to a given port), the port indexing sequence determines the port number (index). If such a port indexing sequence is defined, the ports can be indicated by their indexes in the mapping on which the combined mapping of layers to ports is based.

[0054] In particular, if the port allocation rules define the indexing of ports, the mapping may specify, for example: 1) The layers in each combination of layer-to-port mappings are mapped to consecutively indexed ports ("consecutive mapping"), i.e., there are no gaps between the port indexes in each combination of layer-to-port mappings. 2) Each layer of the first configuration that has a higher rank than the second configuration is mapped to a port with a lower index (where rank is the number of layers in the configuration) than each port to which any layer of the second configuration is mapped ("higher rank priority"). That is, a user terminal with a higher rank (i.e., having more layers (e.g., at least two layers) mapped to a port) is mapped "first" (i.e., to a port with a lower port number than another user terminal with a lower rank (e.g., only one layer)).

[0055] When the flexibility in layer-to-port mapping is increased, the total number of available layer-to-port mapping combinations is reduced by the above mapping principles 1) and 2). Thus, when the layer-to-port mapping combinations are indexed, the number of indexes of the layer-to-port mapping combinations is reduced, and fewer bits are required in the control information to indicate and signal each index corresponding to the layer-to-port mapping combination.

[0056] An example of the application of principles 1) and 2) of the mapping of layers to ports is shown in Table 2. In each row, the index indicates the combination of mapping of layers to ports (i.e., the number of layers for a given user equipment and the ports (port index / number) to which these layers can be mapped. Mapping combinations that are excluded through principles 1) and 2) are crossed out. Table 2 shows four orthogonal ports corresponding to, for example, a 1-symbol DMRS of DMRS configuration 1 proposed for NR. [Table 2]

[0057] For example, mapping principles 1) and 2) are combined. In Table 2, mapping configurations that are not available because of consecutive mappings (principle 1)) are marked with an asterisk (*). Configurations that are not available because principle 1) plus principle 2) ("higher rank precedence") apply are marked with a hash sign (#) (principle 1) and principle 2)).

[0058] However, as another example, each of principles 1) and 2) above for mapping layers to ports can be applied alone.

[0059] Moreover, the application of principles 1) and 2) is not limited to the 1-symbol DMRS configuration 1 as shown in Table 2. Principles 1 and 2) can be similarly applied to other DMRS configurations with a larger number of ports, in which case the reduction effect is even more significant, because the larger the total number of ports, the more available combinations of mapping layers to ports are subject to elimination via either principles 1 and 2). At the same time, sufficient flexibility can be provided due to the remaining available ports and the flexibility provided by the availability of DMRS configurations type 1 and type 2.

[0060] The reference signal is, for example, a forward-located reference signal (particularly, a forward-located DMRS). Therefore, before demodulating data, a channel quality estimation based on the DMRS can be performed, and thus a low latency of data demodulation can be achieved. However, the present disclosure is not limited to the forward-located reference signal. The DMRS can also be located in any symbol of a data frame.

[0061] The resource carrying the reference signal is located in one or more symbols in the time domain. For example, the reference signal can correspond to a one-symbol DMRS or a two-symbol DMRS according to the agreement made on NR. In the case of a two-symbol DMRS, the TD-OCC constitutes one of the resources carrying the reference signal. However, the present disclosure is not limited to a one-symbol reference signal or a two-symbol reference signal, and may use three or more symbols for allocating the reference signal at the beginning (front placement) or other positions of the data section.

[0062] The mapping known to the user equipment 210 and base station 260, for example, implicitly includes indexing of the layer-to-port mapping combinations. In the example of Table 2, the resulting index of the layer-to-port mapping combinations corresponds to the number in the "Index" column of the table. In the example of Table 2, there are 15 indexed combinations of layer-to-port mappings, all of which correspond to a one-symbol DMRS.

[0063] However, in another example, the layer to port mapping combinations are indexed consecutively, including both combinations using one symbol in the time domain and combinations using two or more symbols. That is, a common index is formed through both combinations using one symbol and combinations using two symbols. For example, the first (smaller) index indicates a one-symbol combination (e.g., index 1-15), followed by an index of a two-symbol configuration (e.g., index 16-63), followed by a three-symbol combination (if available), and so on. With such consecutive indexes, including both mapping combinations using one symbol reference signal and mapping combinations using two or more symbols reference signal, indicating a particular mapping configuration implicitly indicates whether there is a one-symbol reference signal, a two-symbol reference signal, or any other number of symbols reference signal.

[0064] The resources allocated to the port include, for example, two resource components according to a first resource component configuration or a second resource component configuration. The first resource component configuration includes a comb and a cyclic shift as resource components. The comb defines a subcarrier distinction, and subcarriers with every other subcarrier index are grouped into different combs. Thus, the first comb consists of subcarriers with odd subcarrier indexes, and the second comb consists of subcarriers with even subcarrier indexes. The second resource component configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC). In particular, the first resource component configuration and the second resource component configuration correspond to the above-mentioned configuration type 1 and configuration type 2, respectively. In operation, the base station 260 configures whether the first resource component configuration or the second resource component configuration is used, and transmits an indicator (i.e., signaling information) to the user equipment 210 indicating whether the first resource component configuration or the second resource component configuration is used. In operation, the circuitry 230 of the user equipment 210 receives this indicator via the user equipment transceiver 220. The indicator of the resource component configuration is transmitted / received via a Radio Resource Control (RRC) protocol that covers multiple functional areas such as system information, measurement configuration and reporting.

[0065] More generally, parameters defining the rules for allocating the ports to their respective resources for carrying reference signals are transmitted by the base station, for example via the RRC protocol, and received by the transmitter.

[0066] The resources assigned to the ports include, for example, either a cyclic shift or a frequency division orthogonal cover code. The circuit 280 of the base station 260 configures, for example, an assignment of a first cyclic shift or a frequency division orthogonal cover code to be applied to a first port and an assignment of a second cyclic shift or a frequency division orthogonal cover code to be applied to a second port, the second cyclic shift or the frequency division orthogonal cover code being different from the first cyclic shift or the frequency division orthogonal cover code. In operation, a first antenna of the multiple antennas receives or transmits data using the first port, and in operation, a second antenna of the multiple antennas receives or transmits data using the second port. The reference signal can be a one-symbol reference signal or a reference signal of two or more symbols, and in the case of a reference signal of two or more symbols, the resources assigned to the ports further include, for example, a TD-OCC.

[0067] According to an example of the present disclosure, the base station 260 determines one or more carrier frequencies to be assigned for transmission and / or reception by the user equipment 210 and transmits an indicator indicating which carrier frequencies are assigned. The user equipment 210 receives the indicator. The circuitry 230 of the user equipment 210 sets whether each port is mapped to one symbol or whether the ports are mapped to one or two symbols according to the assigned carrier frequencies for transmission and / or reception.

[0068] Therefore, two variations are disclosed regarding whether 1-symbol DMRS is used for each port or whether both 1-symbol DMRS and / or 2-symbol DMRS are available. In variation 1, no constraints on the multiplexing scheme are specified at all frequencies. Thus, ports are mapped to 1 or 2 symbols. In contrast, in variation 2, 2-symbol DMRS (and therefore TD-OCC) is not allowed for carrier frequencies above a certain threshold (e.g. 6 GHz).

[0069] For example, the base station 260 transmits, and the user equipment 210 receives, a carrier indicator field (CIF) that specifies the carrier frequencies allocated for transmission / reception. In operation, the circuit 230 of the user equipment 210 thus sets, based on the frequency (or frequency interval) signaled via the CIF, whether each port is mapped to one symbol according to Variation 2 above, or whether the ports are mapped to one or two symbols according to Variation 2.

[0070] The present disclosure further provides a method for transmitting data by a user device 210 to a base station 260 and / or receiving data from a base station 260 by the user device 210 in a communication system using multiple antennas, the method including receiving parameters defining rules for allocating respective resources for carrying reference signals to ports, generating a set of layer-to-port mapping combinations based on mappings known to the user device and the base station, and receiving control information from the base station indicating one combination of the set of layer-to-port mapping combinations to be applied for transmitting and / or receiving data.

[0071] The present disclosure further provides a method for receiving data from a user device 210 by a base station 260 and / or transmitting data to a user device 210 by a base station 260 using multiple antennas, the method including the steps of: transmitting parameters defining rules for allocating respective resources for carrying reference signals to ports; generating a set of layer-to-port mapping combinations based on mappings known to the user device and the base station; and transmitting control information to the user device indicating one combination of the set of layer-to-port mapping combinations to be applied for receiving and / or transmitting data.

[0072] In a non-limiting and exemplary embodiment of the present disclosure, a framework is proposed that obtains input parameters from system level information, RRC signaling, and / or PDCCH signaling, and utilizes these parameters to generate forward placed DMRS port indexing sequence, layer to port mapping, and indication information of 1-symbol forward placed DMRS or 2-symbol forward placed DMRS in a given configuration type based on predefined rules / principles. 1. Definition and signaling of a new parameter (DMRS port indexing type) 2. Principles for generating flexible combinations of layer-to-port mappings 3. Signaling to indicate 1-symbol-forward-aligned or 2-symbol-forward-aligned DMRS

[0073] 3 shows an example framework for DMRS port indexing, layer to port mapping, and indication of 1-symbol or 2-symbol DMRS in forward placed DMRS configurations, respectively. The following steps are shown in FIG. 1. Values ​​of the following parameters or more are indicated for both sides of the transmitter / receiver 220, 270 (i.e. for transmission and / or reception of data by the user equipment 210 and / or base station 260): a) The carrier frequency constitutes the system information that is known to the transmitter or receiver. b) The forward positioned DMRS configuration type is signaled to the transmitter / receiver via RRC. c) The indexing type of the DMRS port is signaled to the transmitter / receiver via RRC or PDCCH by a new parameter. When the new parameter according to c) is configured via RRC, it allows the number of combinations of layer to port mappings to be doubled without increasing the control signaling overhead. 2. Based on the above parameters, a port indexing sequence is defined and the orthogonal DMRS ports are numbered accordingly. 3. Following this, a layer-to-port mapping table is generated, which lists a set of layer-to-port mapping combinations based on (one or more) predefined rules. These rules imply, among other things, mapping principle 1) and principle 2). This can provide increased flexibility compared to the prior art while keeping overhead reasonable, especially in the case of a large number of orthogonal ports (e.g., when the resources to which the ports are assigned include 2-symbol DMRS). Furthermore, orthogonal mapping for MU-MIMO can be achieved. 4. Based on the size of the table, the size of the bitmap for storing the combinations is defined. 5. Next, in any given scenario, indicate the layer-to-port indexing to the user using PDCCH signaling.

[0074] As shown in FIG. 3, one aspect of the present disclosure deals with the indexing sequence of DMRS ports. In current LTE, DMRS ports are assigned fixed numbers regardless of the scenario. For example, as shown in Section 29.1.1 of 3GPP TS 2011-010366, in the LTE downlink, ports with port numbers p7 to p14 are assigned to orthogonal DMRS ports. However, according to the present disclosure, in NR, the assignment of port numbers should be flexible because the multiplexing schemes are different on different ports. The ability to flexibly assign port indexes adds another dimension to the challenge of layer-to-port mapping combinations. In fact, the layer-to-port mapping table is transparent to this flexibility regarding DMRS port indexing. This has the benefit of doubling the number of layer-to-port mapping combinations without increasing the control signaling overhead when configured by RRC.

[0075] Following this, it is disclosed to define a rule(s) to reduce considerably the number of layer to port combinations while still maintaining sufficient flexibility. Either a single rule or a set of rules to reduce the number of combinations can be defined. The general principle can be applied alone or combined with stricter rules to further reduce the number of combinations. In LTE, two separate tables are defined depending on the number of codewords for a given user. The proposed general principle is thus adapted to be usable in a compatible manner with possibly having separate tables for one or more codewords.

[0076] In the following, it is described how the signaling to indicate the presence of 1-symbol DMRS or 2-symbol DMRS in a given forward placed DMRS configuration is handled. A complete example of the proposed mechanism is given below. In this example, the mechanism is applied to the configuration type 2 DMRS configuration shown in Figures 1C and 1D. However, in accordance with the present disclosure, the mechanism can be applied to configuration type 1 settings as well.

[0077] 1. First, the RRC signals, for example, the following parameter values: Carrier frequency: 4GHz Forward DMRS configuration type: 2

[0078] Based on these parameters, two DMRS port indexing types (ie, port numbering types) for 1-symbol DMRS and 2-symbol DMRS respectively for forward placed DMRS configuration type 2 are shown below. 1-symbol DMRS port indexing type 1 (FDM->FD-OCC) as shown in Figure 4A. This numbering type is suitable for two or three port cases to exploit larger diversity in the frequency domain. Indexing type 2 (FD-OCC->FDM) for 1-symbol DMRS ports as shown in Figure 4B. This numbering type is suitable for two-port, three-port or four-port cases to leave resources for data multiplexing. Indexing type 1 (FDM->FD-OCC+TD-OCC) for 2-symbol DMRS ports as shown in Figure 5A. This numbering type is suitable for two or three port cases to exploit larger diversity in the frequency domain. Indexing type 2 (FD-OCC+TD-OCC->FDM) for 2-symbol DMRS ports as shown in Fig. 5B. This numbering type is suitable for 4-port or 8-port cases to exploit larger diversity in the frequency domain.

[0079] In Figures 4A, 4B, 5A and 5B, the respective FDM groups are shown according to their respective representations in Figures 1C and 1D.

[0080] 2. Secondly, select DMRS port indexing type 1, which is configured by, for example, RRC or PDCCH. For indexing type 1, the port indexing sequence is generated according to the order FDM→FD-OCC (1 symbol DMRS) or FDM→FD-OCC+TD-OCC (2 symbol DMRS). For example, "FDM→FD-OCC" means that first the port index (P1-P3) increases in value over all FDM groups for ports with the same FD-OCC (e.g., {1,1}), and then the port index (P4-P6) increases in value again over FDM groups in the same order for ports with the other FD-OCC ({1,-1}). Similarly, for FD-OCC→FDM, first the index increases in value over, for example, {1,1} ports with all FDM groups, and then increases in value over all {1,-1} ports while maintaining the same order of FDM groups. This disclosure is not limited to any particular ordering of FDM groups or FD-OCCs, for example the ordering of FD-OCCs could instead be {1,-1} first and {1,1} second.

[0081] 3. Next, generate tables containing the mapping of layers to ports. Based on the principle "higher ranks are mapped to consecutive DMRS ports first, followed by lower ranks successively" (i.e., a combination of the above principles 1) and 2) for mapping layers to ports), the following tables are generated for both 1-symbol DMRS (Table 3) and 2-symbol DMRS (Table 4), respectively. In these tables, "State" indicates the index of the mapping configuration of layers to ports (corresponding to the "Index" column in Table 2). [Table 3] [Table 4] TIFF2025000846000006.tif32147

[0082] As can be seen from Tables 3 and 4, the 1-symbol DMRS has 15 states that can be indicated by a 4-bit field, and the 2-symbol DMRS has 48 states that can be indicated by a 6-bit field (some states are reserved). Furthermore, if the states of both the 1-symbol DMRS and the 2-symbol DMRS are combined (i.e., indexed consecutively by increasing indices across both the 1-symbol and 2-symbol mapping configurations), the total number is 63, which can still be indicated by a 6-bit field. By generating an indexing column that combines the combination of the layer mapping to the port of the 1-symbol in Table 3 and the layer mapping to the port of the 2-symbol in Table 4, and selecting an index from the combined indexing column, it is implicitly indicated whether the 1-symbol DMRS or the 2-symbol DMRS is used. Therefore, no additional bits are needed to explicitly signal the presence of the 1-symbol DMRS or the 2-symbol DMRS. Instead, one bitmap is used to signal the layer-to-port correspondence that applies to data transmission for both 1-symbol and 2-symbol DMRS of a given combination, thus providing an implicit way to indicate whether 1-symbol or 2-symbol DMRS is present without requiring an additional bit (e.g., a flag indicating 1-symbol DMRS / 2-symbol DMRS).

[0083] In the following, as an example case using the above parameters, consider the case where there are three users / user devices: User 1 has four layers, User 2 has six layers, and User 3 has two layers. Accordingly, User 2 is mapped to P1-P6, User 1 (i.e., User 1's layers) is mapped to P7-P10, and User 3 is mapped to P11-P12, and the following bitmaps are sent to each user respectively (states are combined using one bitmap): User 1: Index(15+34)49->110001 User 2: Index(15+41)55->110111 User 3: Index(15+22)37->100101

[0084] The following provides non-limiting examples of allocation of resources to ports according to configuration type and carrier frequency.

[0085] For centimeter / mm-wave frequency bands (i.e. frequency bands higher than 6 GHz) and forward-located DMRS configuration type 1, depending on the port order signaling, "Comb->CS" or "CS->Comb" is selected when TD-OCC is not allowed, and "Comb->TD-OCC->CS" or "TD-OCC->CS->Comb" is selected when allowed, with higher ranks mapped to consecutive DMRS ports first, followed by lower ranks consecutively, and a single bitmap is used for signaling.

[0086] For cm / mm-wave frequency bands and forward-located DMRS configuration type 2, depending on the port order signaling, when TD-OCC is not allowed, "FDM->FD-OCC->ScID" or "FD-OCC->ScID->FDM" is selected, otherwise "FDM->FD-OCC->TD-OCC" or "FD-OCC->TD-OCC->FDM" is selected, higher ranks are mapped to consecutive DMRS ports first, followed by lower ranks consecutively, and a single bitmap is used for signaling.

[0087] For frequencies below the centimeter / mm-wave frequency bands and forward-located DMRS configuration type 1, depending on the port order signaling, "Comb->TD-OCC->CS" or "TD-OCC->CS->Comb" is selected, with higher ranks mapped to consecutive DMRS ports first, followed by lower ranks mapped consecutively, and a single bitmap is used for signaling.

[0088] For frequencies below the centimeter / mm-wave frequency bands and forward-placed DMRS configuration type 2, depending on the port order signaling, "FDM->FD-OCC->TD-OCC" or "FD-OCC->TD-OCC->FDM" is selected, with higher ranks mapped to consecutive DMRS ports first, followed by lower ranks mapped consecutively, and a single bitmap is used for signaling.

[0089] The DMRS port indexing types are also shown in Tables 5 and 6. Further options are possible, but not necessary. [Table 5] [Table 6]

[0090] In one general aspect, the disclosure provides a user equipment for transmitting data to and / or receiving data from a base station in a communication system using multiple antennas, the user equipment comprising circuitry that, when operative to receive parameters defining rules for allocating respective resources for carrying reference signals to ports, generate a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station, and receive control information from the base station indicating one combination of the set of layer-to-port mapping combinations to be applied for transmitting and / or receiving data.

[0091] This facilitates flexible mapping of layers to ports and flexible configuration of 1-symbol or 2-symbol DMRS in various forward-located DMRS configurations while maintaining a reasonable signaling overhead.

[0092] For example, the rule further defines an indexing sequence of ports, and the mapping specifies that each combination of layers is mapped to ports that are indexed consecutively.

[0093] For example, the mapping may further indicate that each layer of the first configuration having a higher rank than the second configuration is mapped to a port having a lower index than each port to which any layer of the second configuration is mapped, where the rank is the number of layers of the configuration.

[0094] These rules facilitate maintaining a reasonable number of layer-to-port mapping combinations while at the same time providing flexible combinations of layer-to-port mappings.

[0095] In some embodiments, the resource carrying the reference signal is located on one or more symbols in the time domain.

[0096] The mapping, for example, implicitly includes indexing combinations of mappings of layers to ports, where these combinations are indexed consecutively, including both combinations using one symbol in the time domain and combinations using two or more symbols.

[0097] This provides a way to implicitly signal whether a combination using one reference signal or a combination using two or more reference signals is used.

[0098] In some exemplary embodiments, the resources assigned to the port include two resource components, a first resource component configuration includes a comb and a cyclic shift of the reference signal, the comb being composed of either subcarriers with odd subcarrier indices or subcarriers with even subcarrier indices, and a second resource component configuration includes frequency division multiplexing and a frequency division orthogonal cover code (OCC), and the user equipment circuitry further receives an indicator from the base station in operation indicating whether the first or second resource component configuration is used.

[0099] For example, parameters defining the rules for allocating ports to respective resources for carrying reference signals are received via a Radio Resource Control (RRC) protocol.

[0100] This facilitates increasing the number of combinations of layer-to-port mappings without increasing signaling overhead.

[0101] In some embodiments, the processing circuitry of the user equipment, in operation, configures whether each port is mapped to one symbol, or whether the ports are mapped to one or two symbols, according to the carrier frequency assigned for transmission and / or reception.

[0102] For example, in operation, the user equipment circuitry further receives a carrier indicator field (CIF) that specifies the carrier frequency.

[0103] In some embodiments, the reference signal is a forward-located demodulation reference signal.

[0104] In some embodiments, the user equipment further comprises a transceiver that, in operation, applies the indicated combination of layer to port mappings to transmit and / or receive data.

[0105] The present invention further provides a base station for receiving data from and / or transmitting data to a user device in a communication system, the base station comprising: a plurality of antennas for transmitting or receiving data in operation; and a circuit for transmitting parameters in operation defining rules for allocating respective resources for carrying reference signals to ports, generating a set of layer-to-port mapping combinations based on mappings known to the user device and the base station, and transmitting control information to the user device indicating one combination of the set of layer-to-port mapping combinations to be applied to data reception and / or transmission.

[0106] In some embodiments, parameters defining the rules for allocating ports to their respective resources for carrying reference signals are transmitted via a Radio Resource Control (RRC) protocol.

[0107] Moreover, in some embodiments, the base station circuitry further configures, during operation, parameters that define rules for allocating respective resources to ports for carrying reference signals.

[0108] For example, the resources assigned to the ports include either a cyclic shift or a frequency division orthogonal cover code, and the circuit further configures, in operation, an assignment of a first cyclic shift or frequency division orthogonal cover code to be applied to a first port and an assignment of a second cyclic shift or frequency division orthogonal cover code to be applied to a second port, the second cyclic shift or frequency division orthogonal cover code being different from the first cyclic shift or frequency division orthogonal cover code, and a first antenna of the multiple antennas, in operation, receives or transmits data using the first port, and a second antenna of the multiple antennas, in operation, receives or transmits data using the second port.

[0109] According to another general aspect, a method for transmitting data by a user equipment to a base station and / or receiving data from a base station using multiple antennas in a communication system is disclosed, the method including the method steps of receiving parameters defining rules for allocating respective resources for carrying reference signals to ports, generating a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station, and receiving control information from the base station indicating one combination of the set of layer-to-port mapping combinations to be applied for transmitting and / or receiving data.

[0110] The present invention further discloses a method for receiving data from a user equipment by a base station and / or transmitting data to a user equipment by a base station using multiple antennas, the method including the steps of: transmitting parameters defining rules for allocating respective resources for carrying reference signals to ports; generating a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station; and transmitting control information to the user equipment indicating one combination of the set of layer-to-port mapping combinations to be applied for receiving and / or transmitting data.

[0111] In summary, the present disclosure discloses a user equipment, a base station, a method for transmitting / receiving data by the user equipment, and a method for receiving / transmitting data by the base station, the user equipment comprising a circuit that, in operation, receives parameters defining rules for allocating respective resources for carrying reference signals to ports, generates a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station, and receives control information from the base station indicating one combination of the set of layer-to-port mapping combinations to be applied for transmitting and / or receiving data.

Claims

1. An integrated circuit for controlling processing of a base station, the processing comprising: transmitting parameters defining rules for allocating ports to respective resources for carrying reference signals; transmitting to the user equipment control information indicating a combination of a set of layer-to-port mapping combinations based on mappings known to the user equipment and the base station to be applied for data reception and / or transmission; Including, the resource carrying the reference signal is located on one or more symbols in the time domain; The mapping implicitly includes indexing the combinations of mappings of layers to ports, the combinations being indexed consecutively, including both combinations using one symbol in the time domain and combinations using two or more symbols; Among the combinations included in the set of combinations of mapping of layers to ports, when the number of layers using the two or more symbols is two or more, the combination includes a combination in which port numbers are consecutive and a port overlaps with another combination included in the set for the same number of layers. Integrated circuits.

2. The integrated circuit of claim 1 , wherein the parameters defining rules for allocating ports to respective resources for carrying reference signals are transmitted via a Radio Resource Control (RRC) protocol.

3. The integrated circuit of claim 1 , wherein the processing further comprises setting the parameters that define the rules for allocating respective resources to ports for carrying reference signals.

4. The resources assigned to the ports include either a cyclic shift or a frequency division orthogonal cover code, and the process comprises: an assignment of a first cyclic shift or frequency division orthogonal cover code to be applied to a first port; assigning a second cyclic shift or frequency division orthogonal cover code to be applied to a second port, the second cyclic shift or frequency division orthogonal cover code being different from the first cyclic shift or frequency division orthogonal cover code; Further setting receiving or transmitting the data using the first port; receiving or transmitting the data using the second port; 10. The integrated circuit of claim 1 , comprising:

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