Signaling aspects for indicating cooperatively scheduled dmrs ports in mu-mimo

Abstract

To provide a base station and a method for transmitting and receiving data and / or reference signals on resources.SOLUTION: In a communication system, a base station 260 transmits parameters defining a configuration for allocating each resource for carrying a reference signal to a port. Control information indicates cooperative scheduling information, and each resource includes two resource element configurations. The base station further transmits to a mobile terminal 210 an indicator indicating whether a first resource element configuration or a second resource element configuration is used.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The 3rd Generation Partnership Project (3GPP) is currently working towards the publication (Release 15) of technical specifications for next-generation cellular technology, also known as the fifth generation (5G). At the 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) Meeting No. 71 (Gutenberg, March 2016), the first 5G study item, "Study on New Radio Access Technology," which includes RAN1, RAN2, RAN3, and RAN4, was approved and is expected to become a Release 15 work item that will define the first 5G standard.

[0003] One objective of 5G NR is to provide a single technology framework that addresses all usage scenarios, requirements, and deployment scenarios defined in 3GPP TS 2013-01-01001 (available at www.3gpp.org), including at least enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), and massive machine-based communications (mMTC).

[0004] For example, eMBB deployment scenarios may include indoor hotspots, dense urban, rural, urban macro and high speed; URLLC deployment scenarios may include industrial control systems, mobile health management (remote monitoring, diagnosis and treatment), real-time control of vehicles, wide area surveillance, and smart grid control systems; and mMTC may include scenarios using a large number of devices for non-time critical data transfer such as smart wearables and sensor networks.

[0005] Another objective is to achieve backward compatibility: backward compatibility with Long Term Evolution (LTE) is not required, which makes it easier to introduce completely new system designs and / or new features.

[0006] As summarized in one of the technical reports for the NR work item (Non-Patent Document 2), the basic physical layer signal waveform will be based on Orthogonal Frequency Division Multiplexing (OFDM). Waveforms based on OFDM with Cyclic Prefix (CP-OFDM) are supported for both the downlink and uplink. Waveforms based on Discrete Fourier Transform (DFT) Spread OFDM (DFT-S-OFDM), which are complementary to CP-OFDM up to 40 GHz at least for the eMBB uplink, are also supported.

[0007] One of the design goals of NR is to seek waveforms that are as common as possible for the downlink, uplink, and sidelink. It has been considered that introducing DFT spreading may not be necessary in uplink transmissions in some cases. The term "downlink" refers to communication from a higher node to a lower node (e.g., from a base station to a relay node or UE, or from a relay node to a UE, etc.). The term "uplink" refers to communication from a lower node to a higher node (e.g., from a UE to a relay node or base station, or from a relay node to a base station, etc.). The term "sidelink" refers to communication between nodes at the same level (e.g., between two UEs, or between two relay nodes, or between two base stations).

[0008] The term spatial layer (or layer) refers to one of the different streams generated by spatial multiplexing. A layer can be described as a mapping of symbols to transmit antenna ports. Each layer is identified by a precoding vector of size equal to the number of transmit antenna ports and can be associated with one radiation pattern. The transmission rank refers to the number of layers transmitted. A codeword is a separately coded data block that corresponds to a single transport block (TB) sent from the transmitter's medium access control (MAC) layer to the physical layer and protected by a cyclic redundancy check (CRC).

[0009] Generally, one layer is assigned per transmission time interval (TTI) corresponding to a subframe in LTE. However, in 3GPP NR, there may be different TTIs depending on URLLC or eMBB. In particular, in NR, the TTI may be a slot, a minislot, or a subframe. For information on layers, ranks, and codewords, see also Non-Patent Document 3.

[0010] Traditionally, a reference signal pattern (RS) is transmitted from an antenna port (or ports) of a base station. A port can transmit as a single 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 receiver. That is, the transmit RS corresponding to a given antenna port defines the antenna port from the UE's perspective and enables the UE to obtain a channel estimate for all data transmitted on that antenna port, regardless of whether the channel estimate represents a single radio channel from one physical antenna or a composite channel from multiple physical antenna elements that together comprise that antenna port. For more information on ports, see also Non-Patent Document 4.

[0011] In LTE, UE data transmission and reception is scheduled by the eNB using a Physical Downlink Control Channel (PDCCH), which carries messages containing resource allocations and other control information for a UE or group of UEs, called Downlink Control Information (DCI). Typically, several PDCCHs can be transmitted in a subframe.

[0012] The required content of the control channel messages depends on the system deployment and UE configuration. For example, if the infrastructure does not support MIMO or if the UE is configured in a transmission mode that does not include MIMO, there is no need to signal parameters required only for MIMO transmission. Therefore, to minimize 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, to avoid overly complex implementation and testing, it is desirable not to specify too many formats. The set of DCI message formats specified in LTE is listed below.

[0013] Please refer to the above mentioned technical standard or Non-Patent Document 5.

[0014] - Format 0 DCI format 0 is used for transmitting resource grants for PUSCH and uses single antenna port transmission in uplink transmission mode 1 or 2.

[0015] - Format 1 DCI format 1 is used for transmitting resource allocations for single codeword PDSCH transmissions (downlink transmission modes 1, 2 and 7).

[0016] - Format 1ADCI format 1A is used for compact signaling of resource allocation for single codeword PDSCH transmissions as well as for assigning dedicated preamble signatures to mobile terminals for contention-free random access (for all transmission modes).

[0017] - Format 1B DCI Format 1B is used for compact signaling of resource allocation for PDSCH transmissions using closed-loop precoding with rank-1 transmission (downlink transmission mode 6). The transmitted information is the same as in Format 1A, but an indicator of the precoding vector applied to the PDSCH transmission is added.

[0018] - Format 1C DCI Format 1C is used for very compact transmission of PDSCH allocations. When Format 1C is used, PDSCH transmissions are forced to use QPSK modulation. Format 1C is used, for example, to signal paging messages and broadcast system information messages.

[0019] - Format 1D DCI Format 1D is used for compact signaling of resource allocation for PDSCH transmissions using multi-user MIMO. The transmitted information is the same as in Format 1B, but instead of one of the bits for the precoding vector indicator there is a single bit indicating whether a power offset has been applied to the data symbols. This functionality is needed to indicate whether the transmit power is shared between two UEs. Future versions of LTE may extend this functionality to the case of power sharing between multiple UEs.

[0020] - Format 2 DCI format 2 is used to transmit resource allocations for PDSCH for closed-loop MIMO operation (transmission mode 4).

[0021] - Format 2A DCI format 2A is used to transmit resource allocations for PDSCH for open-loop MIMO operation. The transmitted information is the same as format 2, except that if the eNodeB has two transmit antenna ports, there is no precoding information, and two bits are used for four antenna ports to indicate the transmission rank (transmission mode 3).

[0022] - Format 2B : Introduced in Release 9 and used to transmit resource allocation for PDSCH for dual-layer beamforming (transmission mode 8).

[0023] - Format 2C : Introduced in Release 10 and used to transmit resource allocations for the PDSCH for closed-loop single-user or multi-user MIMO operation with up to 8 layers (transmission mode 9).

[0024] - Format 2D :Introduced in Release 11, it is used for up to 8 layer transmission and is primarily used for COMP (Cooperative Multipoint) (transmission mode 10).

[0025] - Format 3 and 3A DCI formats 3 and 3A are used for transmitting 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.

[0026] - Format 4 DCI format 4 is used for scheduling of the PUSCH and uses closed-loop spatial multiplexing transmission in uplink transmission mode 2.

[0027] A search space indicates the set of CCE locations where a UE can find its PDCCH. Each PDCCH carries one DCI and is identified by a Radio Network Temporary Identifier (RNTI) implicitly coded in the CRC attachment of the DCI. The UE monitors the CCEs in the configured search space by blind decoding and CRC checking. The search spaces can be a common search space and a UE-specific search space. The UE must monitor both the common search space and the UE-specific search space, which may overlap. The common search space carries DCI that is common to all UEs, such as system information (using SI-RNTI), paging (P-RNTI), PRACH response (RA-RNTI), or UL TPC commands (TPC-PUCCH / PUSCH-RNTI). The UE-specific search space can carry DCI for UE-specific assignments using the UE's assigned C-RNTI, semi-persistent scheduling (SPS C-RNTI), or initial assignment (temporary C-RNTI).

[0028] The DCI thus specifies the resources on which the UE receives or transmits data, including the transmission and reception configuration. [Prior art documents] [Non-patent literature]

[0029] [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] section 11.2.2.2 of S. Sesia, I. Toufik and M, Baker, LTE: The UMTS Long Term Evolution, Second Edition [Non-patent document 4] section 8.2 of S. Sesia, I. Toufik and M, Baker, LTE: The UMTS Long Term Evolution, Second Edition [Non-Patent Document 5] LTE - The UMTS Long Term Evolution - From Theory to Practice, Edited by Stefanie Sesia, Issam Toufik, Matthew Baker, Chapter 9.3.5 [Non-patent document 6] 3GPP TSG RAN Meeting #75, RP-171485 by NTT DoCoMo, “Revised WID on New Radio Access[] Technology”, June 5-8, 2017 [Non-Patent Document 7] RAN1 NR#3 (RAN1 Chairman Notes: RAN1 NR Ad-Hoc#3) [Non-patent document 8] section 29.1.1 of S. Sesia, I. Toufik and M, Baker, LTE: The UMTS Long Term Evolution, Second Edition [Non-Patent Document 9] 3GPP TS 36.212, V14.3.0 (Table 5.3.3.1.5C-2) Summary of the Invention

[0030] In one non-limiting and exemplary embodiment, in a mobile communication system where data is transmitted and / or received within layers using multiple antennas, signaling of coordinated scheduling information (non-transparent MU-MIMO) is facilitated for each code division multiplexing (CDM) group. More specifically, the present disclosure proposes a set of layer and port mapping combinations that are combined with the coordinated scheduling information to facilitate a more efficient and effective signaling mechanism.

[0031] A main aspect of the present disclosure is a base station, a circuit, the circuit comprising: transmitting parameters defining a configuration for allocating resources to ports for carrying reference signals, the resources being grouped into a plurality of code division multiplexing (CDM) groups; transmitting control information indicating one of a set of layer / port mapping combinations to be applied to place reference signals on ports of at least one CDM group for data transmission and / or reception; the control information indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among a plurality of CDM groups for the same data transmission and / or reception; a transceiver that controls transmission and / or reception of data within a layer based on the coordinated scheduling information; Equipped with each of the resources assigned to the port includes two resource element configurations; the first resource element configuration includes a comb and a cyclic shift of a reference signal, the comb being composed of subcarriers having either odd subcarrier indices or even subcarriers having even subcarrier indices; the second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC); the circuitry further transmits to a mobile terminal an indicator indicating whether the first resource element configuration or the second resource element configuration is being used. It is a base station.

[0032] Another aspect of the present disclosure is a communication system including a mobile terminal and a base station, The mobile terminal a circuit, the circuit comprising: receiving parameters defining a configuration for allocating resources to ports for carrying reference signals, the resources being grouped into a plurality of code division multiplexing (CDM) groups; receiving control information indicating one of a set of layer / port mapping combinations to be applied to place reference signals on ports of at least one CDM group for data transmission and / or reception; the control information indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among a plurality of CDM groups for the same data transmission and / or reception; a transceiver configured to transmit and / or receive data within a layer using multiple antennas based on the coordinated scheduling information; Equipped with each of the resources assigned to the port includes two resource element configurations; the first resource element configuration includes a comb and a cyclic shift of a reference signal, the comb being composed of subcarriers having either odd subcarrier indices or even subcarriers having even subcarrier indices; the second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC); the circuit further receives an indicator from a base station indicating whether the first resource element configuration or the second resource element configuration is being used; The base station a base station circuit, the base station circuit comprising: transmitting parameters defining a configuration that allocates resources to each port for carrying the reference signal; transmitting control information indicating one of a set of layer / port mapping combinations; a base station transceiver for transmitting and / or receiving data within a layer using multiple antennas based on the coordinated scheduling information; Equipped with The base station circuitry further transmits the indicator to the mobile terminal.

[0033] In one embodiment, the techniques disclosed herein feature a mobile terminal including: circuitry for receiving parameters defining a configuration for allocating resources, grouped into a plurality of code division multiplexing (CDM) groups, to ports for carrying reference signals; and receiving control information indicating one of a set of layer / port mapping combinations to be applied for placing reference signals on ports of at least one CDM group for transmission and / or reception of data, the control information indicating coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among a plurality of CDM groups for the same data transmission and / or reception; and a transceiver for transmitting and / or receiving data within a layer using a plurality of antennas based on the coordinated scheduling information.

[0034] It should be noted that the general or specific embodiments may be realized as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof.

[0035] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. These benefits and / or advantages may be obtained individually by various embodiments and features of the specification and drawings, but not all of these embodiments and features are necessary to obtain one or more of such benefits and / or advantages. [Brief explanation of the drawings]

[0036] [Figure 1-1] 1A and 1B are schematic diagrams of front loaded demodulation reference signal (DMRS) configuration types. [Figure 1-2] 1C and 1D are schematic diagrams of forward demodulation reference signal (DMRS) configuration types. [Figure 2] FIG. 2 is a block diagram showing the configuration of a mobile terminal and a base station. [Figure 3] 10 illustrates an example set of layer / port mapping combinations combined with coordinated scheduling information for each CDM group for DMRS configuration type 1 and 1-symbol DMRS configuration. [Figure 4] 10 illustrates an example set of layer / port mapping combinations combined with coordinated scheduling information for each CDM group for DMRS configuration type 1 and 2-symbol DMRS configurations. [Figure 5] 10 illustrates an example set of layer / port mapping combinations combined with coordinated scheduling information for each CDM group for DMRS configuration type 2 and for a 1-symbol DMRS. [Figure 6A]10 illustrates an example set of layer / port mapping combinations combined with coordinated scheduling information for each CDM group for DMRS configuration type 2 and for a two-symbol DMRS. [Figure 6B] 10 illustrates an example set of layer / port mapping combinations combined with coordinated scheduling information for each CDM group for DMRS configuration type 2 and for a two-symbol DMRS. DETAILED DESCRIPTION OF THE INVENTION

[0037] In the 3rd Generation Partnership Project New Radio (3GPP NR), reference signals have been redesigned to suit a wide range of requirements and use cases. Demodulation Reference Signals (DMRSs) used for channel estimation purposes are also designed to have a uniform structure in both the uplink and downlink using a cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) waveform. This disclosure relates to signaling aspects for supporting non-transparent multi-user multiple-input multiple-output (MU-MIMO). Two configurations of forward DMRS (with different multiplexing schemes for orthogonal DMRS ports) will be supported, with the flexibility to use one-symbol or two-symbol DMRS for each configuration.

[0038] Currently, LTE has a fixed configuration with a single category of multiplexing scheme for orthogonal DMRS ports, and no support for non-transparent MU-MIMO.

[0039] However, in 3GPP NR, the situation is more complicated due to the potential for increased interference from co-scheduled DMRS ports to other UEs. In addition, rate matching is required due to frequency division multiplexing (FDM) between different DMRS ports. This is why NR is expected to support UE-non-transparent MU-MIMO. This disclosure provides a framework for indicating at least some information about co-scheduled DMRS ports in the same and / or different CDM groups in MU-MIMO by adding a new field to the DMRS layer-to-port mapping table.

[0040] This disclosure relates to NR technology. NR access technology is described in Non-Patent Document 6. More specifically, NR access technology addresses forward DMRS aspects in both downlink and uplink using CP-OFDM waveforms. In Non-Patent Document 7, DMRS is incorporated, which provides a framework for signaling at least some information related to coordinately scheduled DMRS ports by using a DMRS layer-to-port mapping table.

[0041] As mentioned above, in 3GPP NR, the demodulation reference signals (DMRS) are redesigned for both the downlink and uplink.

[0042] Two configurations, shown in FIGS. 1A-1D, are supported for forward DMRS on the downlink and uplink using CP-OFDM waveforms.

[0043] As shown, the forward reference signal is allocated to the resource of the first data symbol adjacent to the resource of the signaling section of the TTI (e.g., a signaling section consisting of two symbols) when 1-symbol DMRS is used, and to the resource of the first two data symbols when 2-symbol DMRS is used.

[0044] 1A and 1B show example resource grids corresponding to a slot of 14 symbols and 12 subcarriers, respectively. The first two symbols on the left side of each diagram correspond to the signaling section of the slot. The Physical Downlink Control Channel (PDCCH) is signaled in the signaling section. In LTE, this example resource grid would correspond to one of two slots of a subframe. However, this is not a limitation of the present disclosure, as a subframe may correspond to a (single) slot or may include three or more slots, and a slot may have more or fewer than 14 symbols and more or fewer than 12 subcarriers.

[0045] A first forward DMRS configuration, corresponding to configuration type 1, is shown in FIGS. 1A and 1B. This configuration aims to support up to eight orthogonal DMRS ports for single-user multiple-input multiple-output (SU-MIMO) or multi-user multiple-input multiple-output (MU-MIMO). The first configuration supports up to four orthogonal DMRS ports when one-symbol DMRS is used, as shown in FIG. 1A. In particular, two combs and two cyclic shifts (CSs) can be combined to form up to four component sets, and each resulting component set can be assigned to up to four DMRS ports. These component sets are also referred to as CDM groups in the context of this disclosure.

[0046] As shown in Figure 1B, when two-symbol DMRS is used, two combs and two cyclic shifts can be 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 DMRS ports. However, in the case of two-symbol DMRS, it should also be possible to schedule up to four DMRS ports without using {1,1} and {1,-1}.

[0047] The second forward DMRS configuration, corresponding to configuration type 2, is shown in Figures 1C and 1D. This configuration enables support for up to 12 orthogonal ports for SU-MIMO or MU-MIMO. In particular, two (Walsh-Hadamard) frequency-division orthogonal cover codes (FD-OCCs), each applied across adjacent resource elements (REs) in the frequency domain, generate six component sets, or CDM groups.

[0048] As can be seen from Figures 1C and 1D, for 12 subcarriers, adjacent RE pairs are grouped into three frequency division multiplexing (FDM) groups. Therefore, six component sets are obtained from two FD-OCCs (both {1,1} and {1,-1}) applied to the three FDM groups, respectively. In the case of 1-symbol DMRS (Figure 1C), each of the six resulting component sets can be assigned to up to six orthogonal DMRS ports. In the case of 2-symbol DMRS, these six component sets can be further combined with two TD-OCCs to obtain the ability to support up to 12 orthogonal DMRS ports (Figure 1D).

[0049] As described above with reference to FIGS. 1A to 1D, the comb, cyclic shift, FD-OCC, FDMs, and TD-OCC constitute resource elements for reference signals, particularly for forward DMRS.

[0050] These resource elements are combined according to the first or second forward DMRS configuration, and the resulting component sets or CDM groups are each assigned to orthogonal DMRS ports. However, the use of two-symbol DMRS should also be possible at lower ranks. Not all component sets or CDM groups supported by a particular configuration for one-symbol or two-symbol DMRS need to be used for port allocation. In particular, even in the two-symbol case, it should be possible to schedule six DMRS ports without using both {1,1} and {1,-1}.

[0051] From the perspective of a user equipment (UE), DMRS ports multiplexed by frequency domain code division multiplexing (CDM) are roughly co-located.

[0052] Whether the UE's forward DMRS configuration type can be different between UL and DL is still open to further discussion. Furthermore, if the above agreement involves significant complexity / performance issues, down-selection can still be discussed.

[0053] LTE DMRS configuration

[0054] The DMRS configuration in 3GPP NR described above differs from LTE, which primarily has a single downlink configuration that supports up to a total of eight orthogonal ports / layers using frequency and time code division multiplexing with Walsh-Hadamard orthogonal cover codes. The configuration and further details on the DMRS configuration in LTE can be found in Non-Patent Document 8.

[0055] A table of current LTE layer and port mappings, taken from Non-Patent Document 9, is shown in Table 1 below.

[0056] [Table 1]

[0057] LTE supports up to eight orthogonal DMRS ports for the downlink and primarily uses a single category of multiplexing scheme (OCC for time / frequency). Therefore, any port combination can be used to map layers without affecting the operation of a given scenario. Furthermore, for a given number of layers, resource (DMRS overhead) usage is the same for any port combination.

[0058] Furthermore, LTE provides limited support for MU-MIMO, and a fixed DMRS configuration is supported, therefore no additional signaling is required for dynamic configuration.

[0059] As can be seen from Table 1, LTE has a very limited number of possible layer-to-port mapping combinations. A bitmap of length 4 is defined to indicate the layer-to-port mapping for a given user. A minimum number of port combinations is supported resulting in layer-to-port mapping with the following restrictions: For up to two layers, the port indexing for the mapping is contiguous and non-overlapping. For three to eight layers, the indexing is contiguous, non-overlapping, and starts with index 0 as a fixed starting point. The mapping is limited to one port combination.

[0060] The latest release of LTE supports only transparent MU-MIMO (and not non-transparent MU-MIMO), but this has not always been the case.

[0061] In LTE Rel-8, when MU-MIMO was first introduced to support transmission to up to two UEs, non-transparent MU-MIMO was introduced by dedicating one bit to the power offset field. Nevertheless, support for non-transparent MU-MIMO for more than two UEs was never agreed upon, especially not in more recent LTE releases. It was determined that the disadvantages of increased signaling overhead did not outweigh the resulting benefits.

[0062] DMRS requirements for NR

[0063] The layer and port mapping restrictions of LTE are no longer tenable in 3GPP NR, especially with the demand for non-transparent MU-MIMO to benefit from the advantages of new system designs in 3GPP NR.

[0064] For example, in order to bring support for non-transparent MU-MIMO into 3GPP NR, the decision made for LTE to not incorporate a dedicated bit field could be reconsidered, but again, currently there is a dedicated bit field for MU-MIMO, so support is not needed.

[0065] Description of the embodiment

[0066] The present disclosure facilitates signaling of coordinated scheduling information (non-transparent MU-MIMO) for each code division multiplexing (CDM) group in a mobile communication system where data is transmitted and / or received within a layer using multiple antennas. More specifically, the present disclosure proposes a set of layer-to-port mapping combination information that is combined with the coordinated scheduling information to facilitate a more efficient and effective signaling mechanism.

[0067] 2, the present disclosure presents a mobile terminal 210 that transmits and / or receives data to and from a base station 260 that uses multiple antennas in a mobile communication system. The mobile terminal 210 and the base station 260 are configured to transmit and / or receive data over a wireless channel 250.

[0068] The mobile terminal 210 may correspond to what is commonly referred to in LTE and NR as user equipment (UE), and the base station 260 may correspond to what is commonly referred to in LTE and NR as an evolved NodeB (eNodeB or eNB) or next generation NodeB (gNode or BgNB).

[0069] More specifically, the mobile terminal 210 is configured to transmit and / or receive data in layers to and from the base station 260. As discussed above, the term layer (or spatial layer) refers to one of various streams that are generated by spatial multiplexing and then exchanged between the mobile terminal 210 and the base station 260 over separate antenna ports.

[0070] For coherent demodulation of transmitted and (subsequently) received data, reference signals are also exchanged between mobile terminal 210 and base station 260. As discussed above, the transmission and / or reception of reference signals is performed with reference to a layer-to-port mapping, which specifies, for each layer, one DMRS port to be used to transmit / receive the reference signal.

[0071] In particular, the layer-to-port mapping varies depending on the configuration of base station 260 and mobile terminal 210, i.e., the configuration specified by the DMRS configuration type (e.g., DMRS configuration type 1 or 2) and the number of symbols to be used for the DMRS (e.g., 1-symbol or 2-symbol DMRS). As discussed above, this configuration not only determines the resources for carrying the DMRS, but also the maximum number of DMRS ports that can be scheduled by base station 260.

[0072] In other words, the mobile terminal 210 and the base station 260 revert to different layer-to-port mappings depending on which of multiple configurations is selected for communication in the mobile communication system. The DMRS port configurations are specified so that the base station 260 and the mobile terminal can use the layer-to-port mappings to transmit and / or receive data.

[0073] To this end, the mobile terminal 210 comprises circuitry, e.g., a transceiver 220 and a processor 230, which, in operation, receives parameters defining a configuration for allocating respective (time-frequency) resources carrying reference signals to DMRS ports. In other words, the configuration allocates each of the reference signals of one or more DMRS ports to a particular resource, sometimes represented as a (resource) element set.

[0074] The resources or (resource) element sets are grouped into multiple code division multiplexing (CDM) groups. In particular, the code division multiplexing (CDM) groups specify for each DMRS port a resource or (resource) element set for carrying reference signals, such that each resource or (resource) element set allows a maximum number of orthogonal reference signals, e.g., two or four, to be carried on each DMRS port of the same CDM group.

[0075] Referring to the example shown in Figure 1A, the resources of two combs (comb1, comb2), each with two cyclic shifts (resulting in two different sets of DMRS ports), define separate CDM groups (CDM group 0, CDM group 1). In the example shown in Figure 1B, the resources of two combs (comb1, comb2), each with two cyclic shifts and two TD-OCCs (resulting in four different sets of DMRS ports), define separate CDM groups (CDM group 0, CDM group 1).

[0076] Further, in the example shown in Figure 1C, the resources of three FDM groups (FDM1, FDM2, FDM3), each having two FD-OCCs (resulting in two different sets of DMRS ports), define separate CDM groups (CDM group 0, CDM group 1, CDM group 2). Finally, in the example shown in Figure 1D, the resources of three FDM groups (FDM1, FDM2, FDM3), each having two FD-OCCs and two TD-OCCs (resulting in four different sets of DMRS ports), define separate CDM groups (CDM group 0, CDM group 1, CDM group 2).

[0077] As already mentioned above, the (time-frequency) resources for carrying reference signals are grouped into multiple code division multiplexing (CDM) groups. In particular, in the context of the present disclosure, a CDM group refers to a set of DMRS ports that use the same resources and are orthogonal to each other by using orthogonal cover codes (OCD) or time and / or frequency code division multiplexing (CDM).

[0078] In the context of this disclosure, a CDM group is referred to from the perspective of a mobile terminal 210. At the mobile terminal 210, a CDM group refers to a set of resources or (resource) elements of DMRS ports that are roughly co-located.

[0079] Again, for the exemplary embodiment, the circuitry of mobile terminal 210, e.g., transceiver 220 and processor 230, in operation receives control information indicating one of a set of layer and port mapping combinations to be applied to place reference signals on DMRS ports of at least one CDM group for transmission and / or reception of data.

[0080] Next, mobile station 210 determines a DMRS port using the indicated one of the set of layer-port mapping combinations and determines, for this DMRS port, the respective resources for data transmission and / or reception based on the resource or (resource) element set configuration. In other words, only in combination, the configuration and the indicated layer-port mapping enable data transmission and / or reception.

[0081] However, the configuration parameters and the control information are not both received simultaneously by the mobile terminal 210. Rather, the base station 260 may signal the configuration parameters infrequently, for example, via a radio resource control (RRC) protocol, while the control information may be signaled via a physical downlink control channel (PDCCH) together with scheduling information in downlink control information (DCI).

[0082] Furthermore, for the exemplary embodiment, the received control information, however, is not limited to only indicating one of a set of layer-to-port mapping configurations to mobile terminal 210. Rather, the received control information also indicates coordinated scheduling information to mobile terminal 210 for each of the CDM groups.

[0083] This coordinated scheduling information can then be utilized for transmission and / or reception of the same data, i.e., to improve interference cancellation and / or rate matching for transmission and / or reception of data of the same TTI.

[0084] Signaling cooperative scheduling information for each CDM group provides a favorable trade-off with respect to non-transparent MU-MIMO signaling. In particular, signaling cooperative scheduling for each CDM group offers the advantage of minimizing signaling overhead for improved interference cancellation and / or rate matching adaptation to increase data transmission capacity.

[0085] In the following, a distinction is made between the indication of coordinated scheduling information to CDM groups for which mobile terminal 210 is scheduled to perform reference signal transmission and / or reception (hereinafter referred to as a first set of CDM groups) and other CDM groups (hereinafter referred to as a second set of CDM groups) that are not scheduled for mobile terminal 210. However, this distinction becomes even clearer when the advantages gained by the coordinated scheduling information are considered.

[0086] As noted above, mobile terminal 210 can use cooperative scheduling indications for improved interference cancellation.

[0087] In each CDM group, the base station coordinates scheduling among different mobile terminals to assign reference signals to DMRS ports of the same resource (in the same CDM group). Although the DMRS ports are said to be orthogonal to each other within a CDM group, there may be interference between the reference signals, which may result in degradation of the reception quality of the reference signals. This interference therefore reduces the ability to coherently demodulate data transmission and / or reception.

[0088] Here, the additional coordinated scheduling information based on the CDM group allows the mobile station to know the coordinated scheduling of the CDM group, i.e., the resources, that also carry its own reference signal, i.e., this additional coordinated scheduling information allows the mobile station to perform interference cancellation on the reference signal, thereby improving the coherent demodulation capability.

[0089] It should be noted, however, that the improvement in interference cancellation is related to the coordinated scheduling information in the CDM groups in which the mobile terminal 210 is scheduled to transmit and / or receive reference signals (the first set of CDM groups).

[0090] Additionally, mobile terminal 210 can use cooperative scheduling indications for improved rate matching.

[0091] In each CDM group, the base station can schedule different mobile terminals to assign reference signals to DMRS ports of different resources (e.g., different CDM groups). Although scheduling DMRS ports of different CDM groups is optimal for the interference characteristics of the CDM groups, this scheduling prevents mobile terminals from reusing different resources (from contexts) for transmitting and / or receiving data.

[0092] In other words, the information about the (actual) allocation of reference signals to separate resources (of separate CDM groups) puts the mobile terminal in a position where it can decide to allocate symbols carrying data transmission and / or reception to this (additional) separate resource (of separate CDM groups). This obviously increases the data transmission capacity in each TTI and therefore requires adapted rate matching to take advantage of this increased data transmission capacity.

[0093] Now, with the additional coordinated scheduling information based on CDM groups, the mobile station is aware of the coordinated scheduling of other CDM groups, i.e., resources, that do not carry its own reference signal, i.e., this additional coordinated scheduling information allows the mobile terminal to then determine whether it can reuse these resources from different CDM groups for data transmission and / or reception, which requires adapted rate matching in response to the increased data transmission capacity.

[0094] It should be noted that the improved rate matching for transmission and / or reception of data in the same TTI is however only relevant for coordinated scheduling information in separate CDM groups in which the mobile terminal is not scheduled to perform transmission and / or reception of reference signals (second set of CDM groups).

[0095] In summary, the benefits of improved interference cancellation and rate matching adaptation to increase data transmission capacity, both of which are linked to the existence of coordinated scheduling information for each CDM group, may depend on whether coordinated scheduling is indicated for CDM groups in which mobile terminals are scheduled to perform reference signal transmission (first set of CDM groups) or not (second set of CDM groups).

[0096] Therefore, it has now become clear that the present disclosure has already demonstrated that indicating coordinated scheduling information provides advantageous effects, even if the coordinated scheduling information is only signaled for a subset of multiple CDM groups rather than all of them.

[0097] In the context of the present disclosure, coordinated scheduling information is signaled for each CDM group, which should be understood as indicating to a mobile terminal that the base station is coordinately scheduling another mobile terminal on a DMRS port of each resource of the CDM group for reference signal transmission and / or reception.

[0098] Depending on the CDM group to which the coordinated scheduling information is provided, it may be advantageous to interpret the coordinated scheduling information differently.

[0099] For the second set of CDM groups, the coordinated scheduling information allows the mobile terminal to adapt its rate matching to benefit from increased data transmission capacity. Notably, to do this, the mobile terminal only needs to know whether there is (or is not) at least one other mobile terminal assigned to a DMRS port in another CDM group.

[0100] If one of the second set of CDM groups has at least one assigned DMRS port, the transmission and / or reception of the respective reference signal is deemed to be more important than adapting rate matching and benefiting from the increased data transmission capacity. Otherwise, the mobile terminal may adapt rate matching to take advantage of the increased data transmission capacity.

[0101] Therefore, for the second set of CDM groups, the coordinated scheduling information can thus be interpreted as indicating "at least one" different mobile terminal being scheduled per CDM group.

[0102] For the first set of CDM groups, the coordinated scheduling information allows mobile terminals to benefit from improved interference cancellation. However, improved interference cancellation is only needed when there are more than a given number (represented as number X in FIGS. 3-6), e.g., more than one (e.g., two or three) mobile terminals assigned separate DMRS ports of the same CDM group in the first set.

[0103] Alternatively, if there are fewer than a given number of mobile terminals, e.g., one or none, assigned separate DMRS ports of the same CDM group in the first set, then it can be reasonably expected that the existing mechanisms will work sufficiently to establish orthogonal DMRS ports.

[0104] For example, in a 3GPP NR deployment scenario, interference cancellation is improved by utilizing a blind interference detection mechanism at the receiver of the reference signal, whereby improved reception performance of the reference signal is achieved even without any prior knowledge of the interference at the receiver (only coordinated scheduling information indicates that there is interference from a given number of mobile terminals, e.g., two or three).

[0105] However, blind interference detection mechanisms are computationally complex, costly in terms of power consumption, and introduce non-negligible processing delays into the signaling flow, so they are only advantageous if a lot of interference is (actually) exhibited. To this end, the number of cooperative scheduling interferences exhibited in the first set of CDM groups (represented as number X in Figures 3-6) is different from the number of cooperative scheduling interferences exhibited in the second set of CDM groups.

[0106] In other words, the interpretation of the coordinated scheduling information may depend on the CDM group, and thus on the set of CDM groups for which the coordinated scheduling information is received. If the coordinated scheduling information is received for a CDM group of a first set for which its own reference signal is carried, the coordinated scheduling information may indicate the presence of a given number of coordinated scheduled mobile terminals per CDM group compared to the CDM groups of a second set, in which case the coordinated scheduling information may indicate the presence of any coordinated scheduled mobile terminals per CDM group.

[0107] Similar to the above, the present disclosure also presents a base station 260 for transmitting and / or receiving data to and from a mobile terminal 210 using multiple antennas in a mobile communication system, where again, the base station 260 and the mobile terminal 210 are configured to transmit and / or receive data over a wireless channel 250.

[0108] The base station 260 comprises circuitry, e.g., a transceiver 270 and a processor 280, which, in operation, transmits, to the mobile terminal 210, parameters defining a configuration that allocates resources grouped into multiple code division multiplexing (CDM) groups to ports for carrying reference signals, and transmits, to the mobile terminal 210, control information indicating one of a set of layer and port mapping combinations to be applied for placing reference signals on ports of at least one CDM group for transmitting and / or receiving data.

[0109] Additionally, the control information also indicates coordinated scheduling information for at least one CDM group and / or at least one other CDM group of the plurality of CDM groups for the same data transmission and / or reception.

[0110] Reference is now made to the manner in which control information is conveyed between base station 260 and mobile station 210. To this end, reference is made to Figures 3-6 as exemplary implementations of signaling mechanisms.

[0111] As already discussed above, the control information (column 1 in each figure) is configured to not only indicate to the mobile terminal 210 one of a set of layer and port mapping configurations (columns 2 and 3 in each figure), but also to indicate to the mobile terminal 210 coordinated scheduling information (columns 4 and 5 or columns 4-6 in each figure) for each CDM group.

[0112] In this respect, a mobile terminal 210 receiving the control information, for example in binary form, refers to the corresponding indexed row (in column 1 of each figure) and thus obtains the layer-to-port mapping indicated by the base station and also the coordinated scheduling information for each of the CDM groups. As can be seen, it is proposed to provide separate rows with the same port-to-layer mapping in the control information in order to reflect all possible permutations of the coordinated scheduling information.

[0113] 3 shows an example set of layer-to-port mapping combinations (columns 2 and 3) combined with coordinated scheduling information for each CDM group (columns 4 and 5) for DMRS configuration type 1 and 1-symbol DMRS configuration. Thus, this example is based on allocating DMRS ports to the resources shown in FIG. 1A, and a total of two DMRS ports can be scheduled in each of the two CDM groups.

[0114] Similarly, Figure 4 shows an example set of layer and port mapping combinations (columns 2 and 3) combined with coordinated scheduling information for each CDM group (columns 4 and 5) for DMRS configuration type 1 and a two-symbol DMRS configuration. Thus, this example is based on allocating DMRS ports to the resources shown in Figure 1B, and a total of four DMRS ports can be allocated to each of the two CDM groups.

[0115] 5 further illustrates an exemplary set of layer-to-port mapping combinations (columns 2 and 3) combined with coordinated scheduling information (columns 4-6) for each CDM group for DMRS configuration type 2 and one-symbol DMRS. Thus, this example is based on allocating DMRS ports to the resources shown in FIG. 1C, and a total of two DMRS ports can be allocated to each of the three CDM groups.

[0116] 6A and 6B further illustrate an exemplary set of layer-to-port mapping combinations (columns 2 and 3) combined with coordinated scheduling information (columns 4-6) for each CDM group for DMRS configuration type 2 and a two-symbol DMRS. Thus, this example is based on allocating DMRS ports to the resources shown in FIG. 1D, and a total of four DMRS ports can be scheduled for each of the three CDM groups.

[0117] For all the exemplary embodiments of FIGS. 3-6, it is assumed that the CDM groups and DMRS ports are indexed as follows:

[0118] 1. The CDM groups are consecutively indexed and the DMRS ports of the CDM groups are consecutively indexed, ie, the index of the DMRS ports increases with the index of the CDM groups.

[0119] In other words, when considering a (single) CDM group, the indices of the DMRS ports of this CDM group are consecutively distributed, which can already be inferred from the fact that each DMRS port of a CDM group is consecutively indexed, regardless of the specific CDM group.

[0120] Now considering another CDM group, the indices of the DMRS ports are distributed within the CDM group such that any one of the DMRS ports in a particular CDM group with a lower index has a lower index than any one of the DMRS ports in another particular CDM group with the next higher index.

[0121] Having specified consecutive indexing of CDM groups and DMRS ports, it is also assumed for the exemplary embodiments of Figures 3-6 that the base station assigns DMRS ports to mobile stations consecutively and incrementally (i.e., sequentially) across multiple CDM groups.

[0122] 2. The mobile terminal is assigned DMRS ports from among all the CDM groups with consecutive indices starting from the DMRS port with the lowest index.

[0123] For the sake of discussion, assume that base station 260 assigns the DMRS port with the lowest index (DMRS Port 0, or P0) to mobile terminal 210. In this case, if base station 260 ever wants to assign another DMRS port to the same mobile terminal 210, the base station must proceed to assign the DMRS port with the next higher consecutive index (DMRS Port 1, or P1). Thus, it is not possible for a single mobile terminal to be assigned two DMRS ports that do not have consecutive indexes.

[0124] Reducing the total number of rows that can be indexed as control information reduces the total amount of signaling overhead in control signals. In particular, the inventors have recognized that signaling of control information can be most efficient and effective when the following rules are observed:

[0125] 3. The maximum number of DMRS ports that can be scheduled per mobile terminal in MU-MIMO is limited to a given number, e.g., a number smaller than the maximum number of DMRS ports specified by the configuration for allocating respective resources to ports.

[0126] On the other hand, by reducing the maximum number of DMRS ports per mobile terminal in MU-MIMO, the total number of permutations reflected in the control information indicating the layer-port mapping and cooperative scheduling for each CDM group is drastically reduced.

[0127] On the other hand, if the control information allows indicating an abnormal number of DMRS ports (greater than the maximum number of DMRS ports in MU-MIMO) in terms of layer-port mapping, the mobile terminal can assume that it is operating in SU-MIMO for data transmission and / or reception.

[0128] In the latter case, the mere fact that SU-MIMO is configured does not require additional indication of cooperative scheduling information for any of the CDM groups. Consistent with this, the control information then indicates, for example, that there is no cooperative scheduling.

[0129] For example, this is shown in FIG. 3 for the control information corresponding to index 11 (control information="1011") and the control information corresponding to index 12 (control information="1100"). The figure shows three DMRS ports (ports P0-P2) or four DMRS ports (ports P0-P4), even though the maximum number of DMRS ports per mobile terminal in MU-MIMO is two. Therefore, it can be seen that the mobile terminal is transmitting and / or receiving data in SU-MIMO. That is, there is no coordinated scheduling, and therefore the coordinated scheduling information is "0" for CDM group 0 and "0" for CDM group 1.

[0130] 4. The maximum number of DMRS ports that can be scheduled per mobile terminal in SU-MIMO is limited to a given number, e.g., a number smaller than the maximum number of DMRS ports specified by the configuration for allocating respective resources to ports.

[0131] By reducing the maximum number of DMRS ports per mobile terminal in SU-MIMO, the total number of permutations reflected in the control information indicating layer-port mapping and cooperative scheduling for each CDM group is further reduced.

[0132] For example, this is shown in Figure 5, where despite the availability of a total of eight DMRS ports (ports P0 to P7), the control information index ends with the number 22 (control information = "10110"), which is associated with "only" four ports (ports P0 to P3) operating in SU-MIMO.

[0133] Note that in Figures 4 and 6A / B, there is no SU-MIMO operation mode that can be configured, because the maximum number of ports per mobile terminal in MU-MIMO and SU-MIMO is equal, thereby giving priority to MU-MIMO in indicating cooperative scheduling information.

[0134] 5. A mobile terminal that has been assigned all DMRS ports of a (single) CDM group does not expect coordinated scheduling within the same CDM group.

[0135] This also reduces the number of permutations reflected in the control information indicating layer-to-port mapping and cooperative scheduling for each CDM group.

[0136] For example, this is shown in Figure 3, where for the control information corresponding to index 8 (control information "1000") and the control information corresponding to index 9 (control information "1001"), a total of two DMRS ports (ports P0-P1) of CDM group 0 are assigned to the mobile terminal itself, so that nothing other than the coordinated scheduling information "0" is indicated for this CDM group 0.

[0137] 6. A mobile terminal that is not assigned the lowest indexed DMRS port of a (single) CDM group will expect cooperative scheduling within the same CDM group and within CDM groups with lower indices.

[0138] This signaling of coordinated scheduling information to the CDM group takes advantage of the fact that DMRS ports are allocated consecutively and incrementally (as discussed in number 2 above).

[0139] For the sake of discussion, assume that base station 260 assigns to mobile terminal 210 a DMRS port with an intermediate index (DMRS port 1, i.e., P1) rather than the DMRS port with the lowest index (DMRS port 0, i.e., P0). In this case, because base station 260 is requested to assign DMRS ports starting from the lowest index, mobile terminal 210 can infer that the cooperatively scheduled (other) mobile terminal is in the same CDM group to which the assigned DMRS port with index 1 belongs. Therefore, it is natural that the cooperative scheduling information indicated by control information in MU-MIMO is always "1" within the same CDM group.

[0140] For example, as shown in Figure 3, for the control information corresponding to index 3 (control information="0011") and corresponding to index 4 (control information="0100"), the indicated cooperative scheduling information is always "1" within CDM group 0. Therefore, this rule also reduces the total number of permutations.

[0141] This original signaling of coordinated scheduling information applies not only to the CDM group to which the assigned DMRS port belongs, but also to CDM groups with lower indices.

[0142] For the sake of discussion, assume that base station 260 assigns to mobile terminal 210 a DMRS port with an intermediate index (DMRS port 3, i.e., P3) rather than the DMRS port with the lowest index (DMRS port 0, i.e., P0). In this case, because base station 260 is requested to assign DMRS ports starting with the lowest index, mobile terminal 210 can infer that the cooperatively scheduled (other) mobile terminal is in the same CDM group 1 to which the assigned DMRS port with index 3 belongs, and is also in CDM group 0. Therefore, the cooperative scheduling information indicated for CDM group 0 and CDM group 1 by control information in MU-MIMO is always "1".

[0143] For example, as shown in Figure 3, for the control information corresponding to index 7 (control information="0111"), the indicated cooperative scheduling information is always "1" in CDM group 0 and CDM group 1. Therefore, this rule also reduces the total number of permutations.

[0144] The present disclosure can be realized by software, hardware, or software in combination with hardware. Each functional block used in the description of each embodiment above can be partially or entirely realized by an LSI such as an integrated circuit, and each process described in each embodiment can be partially or entirely controlled by the same LSI or a combination of multiple LSIs. The LSI can be formed individually as a chip, or a single chip can be formed to include some or all of the functional blocks. The LSI can include a data input / output unit coupled thereto. In this specification, the LSI may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the level of integration.

[0145] However, the technique for implementing an integrated circuit is not limited to LSI, and may be realized using dedicated circuits, general-purpose processors, or special-purpose processors. In addition, FPGAs (field-programmable gate arrays), which can be programmed after LSI fabrication, or reconfigurable processors, which can reconfigure the connections and settings of circuits located within LSI, may also be used. The present disclosure may be realized as digital or analog processing. If future circuit technology replaces LSI as a result of advances in semiconductor technology or other derivative technologies, functional blocks may also be integrated using that future integrated circuit technology. Bioengineering may also be applied.

[0146] According to a first aspect, a mobile terminal is proposed for transmitting and / or receiving data in layers to and from a base station using multiple antennas in a mobile communication system, the mobile terminal comprising: circuitry that, in operation, receives from the base station parameters defining a configuration for allocating resources grouped into multiple code division multiplexing (CDM) groups to ports for carrying reference signals; and receives from the base station control information indicating one of a set of layer and port mapping combinations to be applied for placing reference signals on ports of at least one CDM group for data transmission and / or reception, the control information additionally indicating coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among the multiple CDM groups for the same data transmission and / or reception.

[0147] According to a second aspect which can be combined with the first aspect, the control information indicates coordinated scheduling information for all or a subset of a plurality of CDM groups.

[0148] According to a third aspect which can be combined with the first or second aspect, the coordinated scheduling information indicates that the base station is coordinately scheduling different mobile terminals in the at least one and / or another CDM group.

[0149] According to a fourth aspect which may be combined with the first or second aspect, the coordinated scheduling information indicates that the base station is coordinately scheduling at least some different mobile terminals in the at least one and / or another CDM group.

[0150] According to a fifth aspect which can be combined with the first to fourth aspects, the coordinated scheduling information is binary information indicating whether or not coordinated scheduling is performed in each of the plurality of CDM groups.

[0151] According to a sixth aspect which can be combined with the first to fifth aspects, the plurality of CDM groups are assigned consecutive indexes, and each port of the plurality of CDM groups is assigned consecutive indexes such that the index of the port increases with the index of the plurality of CDM groups.

[0152] According to a seventh aspect which can be combined with the first to sixth aspects, the coordinated scheduling information indicates coordinated scheduling for only CDM groups among the plurality of CDM groups which have an index equal to or greater than the index of at least one of the CDM groups.

[0153] According to an eighth aspect which can be combined with the first to seventh aspects, resources allocated to ports of a CDM group having an index smaller than the minimum index of the port indicated in the control information for arranging the reference signal are known to be coordinated and scheduled by the base station.

[0154] According to a ninth aspect which can be combined with the first to eighth aspects, the mapping means assigning an index to the combination of layer and port mapping and the coordinated scheduling information.

[0155] According to a tenth aspect which can be combined with the first to ninth aspects, the resources allocated to the port include two resource element configurations, a first resource element configuration includes a comb and a cyclic shift of a reference signal, the comb being configured with either subcarriers having odd subcarrier indices or subcarriers having even subcarrier indices, and a second resource element configuration includes frequency division multiplexing and a frequency division orthogonal cover code (OCC), and in operation, the circuit further receives from a base station an indicator indicating whether the first resource element configuration or the second resource element configuration is being used.

[0156] According to an eleventh aspect which can be combined with the first to tenth aspects, the parameters defining a configuration for allocating resources for carrying reference signals to ports are received via a Radio Resource Control (RRC) protocol.

[0157] According to a twelfth aspect which can be combined with the first to eleventh aspects, the control information indicating one of a set of layer and port mapping combinations and indicating the coordinated scheduling information is received via a physical downlink control channel (PDCCH).

[0158] According to a thirteenth aspect which can be combined with any of the first to twelfth aspects, the reference signal is a forward demodulation reference signal.

[0159] According to a 14th aspect which can be combined with the 1st to 13th aspects, the mobile terminal further comprises a transceiver which applies the indicated layer and port mapping combination to transmit and / or receive data during operation.

[0160] According to a 15th aspect which can be combined with the 1st to 14th aspects, the mobile terminal further comprises a processor which, during operation, performs interference compensation for the received reference signal and / or rate matching for the data transmission and / or reception.

[0161] According to a sixteenth aspect, a method is proposed, executed by a mobile terminal, for transmitting and / or receiving data in layers between a base station using a plurality of antennas in a mobile communication system, the method comprising: receiving from the base station parameters defining a configuration for allocating each resource grouped into a plurality of code division multiplexing (CDM) groups to a port for carrying a reference signal; and receiving from the base station control information indicating one of a set of layer and port mapping combinations to be applied for placing the reference signal on a port of at least one CDM group for transmitting and / or receiving data, wherein the control information additionally indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among a plurality of CDM groups for the same data transmission and / or reception.

[0162] According to a seventeenth aspect which may be combined with the sixteenth aspect, the control information indicates coordinated scheduling information for all or a subset of the plurality of CDM groups.

[0163] According to an 18th aspect which may be combined with the 16th or 17th aspect, the coordinated scheduling information indicates that the base station is coordinately scheduling different mobile terminals in the at least one and / or another CDM group.

[0164] According to a 19th aspect which may be combined with the 16th or 17th aspect, the coordinated scheduling information indicates that the base station is coordinately scheduling at least some different mobile terminals in the at least one and / or another CDM group.

[0165] According to a twentieth aspect which can be combined with the sixteenth to nineteenth aspects, the coordinated scheduling information is binary information indicating whether or not coordinated scheduling is performed in each of the plurality of CDM groups.

[0166] According to a 21st aspect which can be combined with the 16th to 20th aspects, the plurality of CDM groups are assigned consecutive indexes, and each port of the plurality of CDM groups is assigned consecutive indexes such that the index of the port increases with the index of the plurality of CDM groups.

[0167] According to a 22nd aspect which can be combined with the 16th to 21st aspects, the coordinated scheduling information indicates coordinated scheduling for only CDM groups among the plurality of CDM groups which have an index equal to or greater than the index of at least one of the CDM groups.

[0168] According to a 23rd aspect which can be combined with the 16th to 22nd aspects, it is known that resources allocated to ports of a CDM group having an index smaller than the minimum index of the port indicated in the control information for arranging the reference signal are originally coordinated and scheduled by a base station.

[0169] According to a 24th aspect which can be combined with any of the 16th to 23rd aspects, the mapping means assigning an index to the combination of layer and port mapping and the coordinated scheduling information.

[0170] According to a 25th aspect which can be combined with the 16th to 24th aspects, the resources allocated to the port include two resource element configurations, a first resource element configuration including a comb and a cyclic shift of a reference signal, the comb being configured with either subcarriers having odd subcarrier indices or subcarriers having even subcarrier indices, and a second resource element configuration including frequency division multiplexing and a frequency division orthogonal cover code (OCC), and the method includes a further step of receiving, during operation, from a base station an indicator indicating whether the first resource element configuration or the second resource element configuration is being used.

[0171] According to a 26th aspect which can be combined with the 16th to 25th aspects, parameters defining a configuration for allocating respective resources to ports for carrying reference signals are received via a Radio Resource Control (RRC) protocol.

[0172] According to a 27th aspect which can be combined with the 16th to 26th aspects, the control information indicating one of a set of layer and port mapping combinations and indicating the coordinated scheduling information is received via a physical downlink control channel (PDCCH).

[0173] According to a 28th aspect which can be combined with any of the 16th to 27th aspects, the reference signal is a forward demodulation reference signal.

[0174] According to a 29th aspect which may be combined with the 16th to 28th aspects, the method includes a further step of applying the indicated layer and port mapping combination to transmit and / or receive the data.

[0175] According to a 30th aspect which can be combined with the 16th to 29th aspects, the method comprises a further step of performing interference compensation on the received reference signal and / or rate matching for the data transmission and / or reception.

[0176] According to a 31st aspect, a base station is proposed for transmitting and / or receiving data in layers to and from a mobile terminal (210) using multiple antennas in a mobile communication system, the base station comprising: circuits (270, 280) that, when operated, transmit to the mobile terminal parameters defining a configuration for allocating each resource grouped into multiple code division multiplexing (CDM) groups to a port for carrying a reference signal, and transmit to the mobile terminal control information indicating one of a set of layer and port mapping combinations to be applied for placing the reference signal on a port of at least one CDM group for transmitting and / or receiving data, the control information additionally indicating coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among multiple CDM groups for the same data transmission and / or reception.

[0177] According to a 32nd aspect, there is proposed a method, performed by a base station, for transmitting and / or receiving data in layers to and from a mobile terminal using multiple antennas in a mobile communication system, the method comprising: transmitting to the mobile terminal parameters defining a configuration for allocating each resource grouped into multiple code division multiplexing (CDM) groups to a port for carrying a reference signal; and transmitting to the mobile terminal control information indicating one of a set of layer and port mapping combinations to be applied for placing the reference signal on a port of at least one CDM group for transmitting and / or receiving data, wherein the control information additionally indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among multiple CDM groups for the same data transmission and / or reception.

Claims

1. A base station, a circuit, the circuit comprising: transmitting parameters defining a configuration for allocating resources to ports for carrying reference signals, the resources being grouped into a plurality of code division multiplexing (CDM) groups; transmitting control information indicating one of a set of layer / port mapping combinations to be applied to place reference signals on ports of at least one CDM group for data transmission and / or reception; the control information indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among a plurality of CDM groups for the same data transmission and / or reception; a transceiver that controls transmission and / or reception of data within a layer based on the coordinated scheduling information; Equipped with each of the resources assigned to the port includes two resource element configurations; the first resource element configuration includes a comb and a cyclic shift of a reference signal, the comb being composed of subcarriers having either odd subcarrier indices or even subcarriers; the second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC); the circuitry further transmits to a mobile terminal an indicator indicating whether the first resource element configuration or the second resource element configuration is being used. Base station.

2. the control information indicates coordinated scheduling information for all or a subset of the plurality of CDM groups. The base station of claim 1 .

3. The coordinated scheduling information is indicating that the base station is cooperatively scheduling different mobile terminals in the at least one and / or another CDM group; indicating that the base station is cooperatively scheduling at least some different mobile terminals in the at least one and / or another CDM group; and Binary information indicating whether or not cooperative scheduling is performed in each of the plurality of CDM groups. At least one of the following: The base station of claim 1 .

4. the plurality of CDM groups are consecutively indexed, and the ports of the plurality of CDM groups are consecutively indexed such that the port index increases with the index of the plurality of CDM groups. The base station of claim 1 .

5. the coordinated scheduling information indicates coordinated scheduling for a CDM group having an index equal to or greater than an index of the at least one CDM group among the plurality of CDM groups; The base station of claim 1 .

6. The resources allocated to the ports of the CDM group having an index smaller than the minimum index of the ports indicated in the control information for arranging the reference signals are coordinated and scheduled by the base station. The base station of claim 1 .

7. The mapping means indexing the layer / port mapping combination and the coordinated scheduling information. The base station of claim 1 .

8. The parameters defining the configuration for allocating resources to ports for carrying reference signals are transmitted via a Radio Resource Control (RRC) protocol; and / or the control information indicating one of a set of layer / port mapping combinations and indicating the coordinated scheduling information is transmitted via a physical downlink control channel (PDCCH). The base station of claim 1 .

9. The reference signal is a forward demodulation reference signal. The base station of claim 1 .

10. the transceiver unit applies the indicated layer / port mapping combination to transmit and / or receive data; and / or performing interference compensation for the transmitted reference signal and / or rate matching for the data transmission and / or reception; The base station of claim 1 .

11. 1. A method performed by a base station, comprising: transmitting parameters to the mobile terminal defining a configuration for allocating resources to ports for carrying reference signals, the resources being grouped into a plurality of code division multiplexing (CDM) groups; transmitting control information indicating one of a set of layer / port mapping combinations to be applied to place reference signals on ports of at least one CDM group for data transmission and / or reception; the control information indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group among a plurality of CDM groups for the same data transmission and / or reception; controlling transmission and / or reception of data within a layer based on the coordinated scheduling information; Including, each of the resources assigned to the port includes two resource element configurations; the first resource element configuration includes a comb and a cyclic shift of a reference signal, the comb being composed of subcarriers having either odd subcarrier indices or even subcarriers; the second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC); and transmitting to the mobile terminal an indicator indicating whether the first resource element configuration or the second resource element configuration is being used. method.

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