Signaling Modes for Indicating DMRS Ports Scheduled Coherently in MU-MIMO

Abstract

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

Description

Technical Field

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

Background Art

[0002] Currently, the 3rd Generation Partnership Project (3GPP) is working towards the public release (Release 15) of the technical specifications of next-generation cellular technology, also known as 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", including RAN1, RAN2, RAN3, and RAN4, was approved and is expected to become the Release 15 work item that defines the first 5G standard.

[0003] One objective of 5G NR is to provide a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios defined in Non-Patent Document 1 (available at www.3gpp.org), including at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC).

[0004] For example, the eMBB deployment scenario can include indoor hotspots, dense urban areas, rural areas, urban macro, and high speed. The URLLC deployment scenario can include industrial control systems, mobile health management (remote monitoring, diagnosis, and treatment), real-time vehicle control, wide-area monitoring, and smart grid control systems. mMTC can include scenarios that use 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 a completely new system design and / or new features.

[0006] As summarized in one of the technical reports on NR work items (Non-Patent Document 2), the basic physical layer signal waveform will be based on orthogonal frequency division multiplexing (OFDM). For both the downlink and uplink, waveforms based on OFDM with a cyclic prefix (CP-OFDM) are supported. Waveforms based on discrete Fourier transform (DFT)-spread OFDM (DFT-S-OFDM), which is 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. Introducing DFT spread has been considered unnecessary in some cases for uplink transmission. 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, between two relay nodes, or between two base stations).

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

[0009] Generally, one layer is allocated for each transmission time (TTI) interval corresponding to an LTE subframe. However, in 3GPP NR, different TTIs may exist depending on URLLC or eMBB. In particular, in NR, the TTI can be a slot, a mini-slot, or a subframe. Refer also to Non-Patent Document 3 for layers, ranks, and codewords.

[0010] Conventionally, a reference signal pattern (RS) has been transmitted from the antenna ports (or ports) of the base station. A port can transmit as a single physical transmission 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 decomposed by the UE receiver. That is, the transmitted RS corresponding to a given antenna port defines the antenna port from the perspective of the UE and enables the UE to obtain the channel estimation values of all the data transmitted at that antenna port, regardless of whether the channel estimation value represents a single radio channel from a single physical antenna or a composite channel from multiple physical antenna elements including that antenna port. Refer also to Non-Patent Document 4 for ports.

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

[0012] The required content of the control channel message is determined by the system configuration 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 notify the parameters that are only required for MIMO transmission. Therefore, in order to minimize the signaling overhead, it is desirable to be able to utilize several different message formats, each containing the minimum payload required for a specific scenario. On the other hand, in order to prevent the implementation and testing from becoming overly complex, it is desirable that the number of specified formats is not too large. The set of DCI message formats specified in LTE is listed below.

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

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

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

[0016] - Format 1A: DCI format 1A is used (for all transmission modes) for compact signaling of resource allocation for single codeword PDSCH transmission and for allocating dedicated preamble signatures to the mobile terminal for contention-free random access.

[0017] - Format 1B : DCI format 1B is used for compact signaling of resource allocation for PDSCH transmission using closed-loop precoding with rank 1 transmission (downlink transmission mode 6). The information transmitted 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 allocation. When format 1C is used, PDSCH transmission is forced to use QPSK modulation. Format 1C is used, for example, to notify call messages and broadcast system information messages.

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

[0020] - Format 2 : DCI format 2 is used for transmission of resource allocation for PDSCH for closed-loop MIMO operation (transmission mode 4).

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

[0022] - Format 2B : Introduced in Release 9, it is used for the transmission of resource allocation for PDSCH for dual-layer beamforming (transmission mode 8).

[0023] - Format 2C : Introduced in Release 10, it is used for the transmission of resource allocation for PDSCH for closed-loop single-user or multi-user MIMO operation using up to 8 layers (transmission mode 9).

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

[0025] - Format 3 and 3A : DCI formats 3 and 3A are used for the transmission of power control commands for PUCCH and PUSCH using 2-bit or 1-bit power adjustment respectively. These DCI formats include individual power control commands for groups of UEs.

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

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

[0028] The DCI thus specifies the resources for the UE to receive or transmit data including the transmission and reception configuration.

Prior Art Documents

Non-Patent Documents

[0029]

Non-Patent Document 1

Non-Patent Document 2

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

[0031] A main aspect of the present disclosure is a mobile terminal, receiving parameters that define a configuration for allocating each resource for carrying a reference signal to a port, wherein each of the resources is grouped into a plurality of code division multiplexing (CDM) groups, receiving control information indicating one of a set of combinations of layer / port mappings that is applied to place a reference signal at a port of at least one CDM group for transmission and / or reception of data, wherein the control information indicates cooperative scheduling information for the 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, comprising circuitry, wherein each of the resources allocated to the port includes two resource element configurations, a first resource element configuration includes a comb and a cyclic shift of a reference signal, the comb being composed of either subcarriers having an odd subcarrier index or subcarriers having an even subcarrier index, a second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC), wherein the circuitry further receives an indicator from a base station indicating whether the first resource element configuration is being used or the second resource element configuration is being used. It is a mobile terminal.

[0032] Another aspect of the present disclosure is a communication system including a mobile terminal and a base station, wherein the mobile terminal a circuit, and the circuit receives parameters defining a configuration for allocating each resource for carrying a reference signal to a port, and each of the resources is grouped into a plurality of code division multiplexing (CDM) groups, receives control information indicating one of a set of combinations of layer / port mappings applied to place a reference signal on a port of at least one CDM group for data transmission and / or reception, the control information indicates cooperative 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 uses a plurality of antennas to transmit and / or receive data within a layer based on the cooperative scheduling information, and each of the resources allocated to the port includes two resource element configurations, the first resource element configuration includes a comb and a cyclic shift of the reference signal, and the comb is composed of either subcarriers having an odd subcarrier index or subcarriers having an even subcarrier index, the second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC), the circuit further receives an indicator from the 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, and the base station circuit Transmit parameters that define a configuration for allocating each resource for carrying the reference signal to a port, Transmit control information indicating one of a set of combinations of the layer / port mappings, A base station transceiver that uses a plurality of antennas to transmit and / or receive data within a layer based on the coordinated scheduling information, Comprising, The base station circuit further transmits the indicator to the mobile terminal. A communication system.

[0033] In one embodiment, the techniques disclosed herein are for a mobile terminal that receives parameters that define a configuration for allocating each resource, grouped into a plurality of code division multiplexing (CDM) groups, for carrying a reference signal to a port, and receives control information indicating one of a set of combinations of layer / port mappings that is applied to arrange the reference signal on a port of at least one CDM group for data transmission and / or reception, wherein the control information indicates coordinated scheduling information for the 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, a circuit comprising a transceiver that uses a plurality of antennas to transmit and / or receive data within a layer based on the coordinated scheduling information. A mobile terminal characterized by comprising.

[0034] Note that general or specific embodiments can be implemented as a system, method, integrated circuit, computer program, 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 individually obtained by the various embodiments and features of the specification and drawings, but not all embodiments and features are necessary to obtain one or more of such benefits and / or advantages.

Brief Description of the Drawings

[0036]

Figure 1-1

Figure 1-2

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

[0037] In the 3rd Generation Partnership Project New Radio (3GPP NR), reference signals have been redesigned to meet a wide range of requirements and use cases. The Demodulation Reference Signal (DMRS) used for channel estimation is also designed to have a uniform structure in both the uplink and downlink using the Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) waveform. The present disclosure relates to signaling schemes for supporting non-transparent multi-user multiple input multiple output (MU-MIMO). Two configurations of the front DMRS (with different multiplexing schemes for orthogonal DMRS ports) will be supported, and there is adaptability to use 1-symbol or 2-symbol DMRS for each configuration.

[0038] In current LTE, there is 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 complex due to the potential increase in 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. For this reason, it is expected that NR will support UE non-transparent MU-MIMO. In the present disclosure, by adding a new field to the DMRS layer and port mapping table, a framework is provided for indicating at least some information about co-scheduled DMRS ports within the same and / or different CDM groups in MU-MIMO.

[0040] This disclosure relates to NR technology. For NR access technology, refer to Non-Patent Document 6. More specifically, NR access technology addresses the aspects of front-loaded DMRS for both downlink and uplink using the CP-OFDM waveform. In Non-Patent Document 7, DMRS is incorporated, and thereby a framework for signaling at least some information related to coordinated-scheduled DMRS ports is obtained by using a mapping table of DMRS layers and ports.

[0041] As described above, in 3GPP NR, the Demodulation Reference Signal (DMRS) has been redesigned for both downlink and uplink.

[0042] Two configurations shown in FIGS. 1A to 1D are supported for front-loaded DMRS in downlink and uplink using the CP-OFDM waveform.

[0043] As shown in the figure, the front-loaded 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 is allocated to the resources of the first two data symbols when 2-symbol DMRS is used.

[0044] Figures 1A and 1B each show an exemplary resource grid corresponding to a slot consisting 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. The physical downlink control channel (PDCCH) is known in the signaling section. In LTE, this exemplary resource grid will correspond to one of the two slots of a subframe. However, this does not limit the present disclosure. The reason is that a subframe may correspond to a (single) slot, or may include three or more slots, and the number of symbols in a slot may be more or less than 14, and the number of subcarriers may be more or less than 12.

[0045] A first forward DMRS configuration corresponding to configuration type 1 is shown in FIGS. 1A and 1B. This configuration is intended 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). In the first configuration, as shown in FIG. 1A, when 1-symbol DMRS is used, up to four orthogonal DMRS ports are supported. In particular, two comb and two cyclic shifts (CS) can be combined to form up to four component sets, and each of the resulting component sets can be assigned to up to four DMRS ports. These component sets are also represented as CDM groups in the context of the present disclosure.

[0046] As shown in Figure 1B, when 2-symbol DMRS is used, two complex numbers and two cyclic shifts can be combined with two time-division orthogonal cover codes (TD-OCCs), especially Walsh-Hadamard TD-OCCs ({1,1} and {1,-1}), and up to 8 orthogonal DMRS ports can be supported. However, in the case of 2-symbol DMRS, it should also be possible to schedule up to 4 DMRS ports without using {1,1} and {1,-1}.

[0047] A second front DMRS configuration corresponding to configuration type 2 is shown in Figures 1C and 1D. This configuration enables the support of up to 12 orthogonal ports for SU-MIMO or MU-MIMO. In particular, two (Walsh-Hadamard) frequency-division orthogonal cover codes (FD-OCCs) applied respectively across adjacent resource elements (REs) in the frequency domain generate 6 component sets, i.e., CDM groups.

[0048] As can be seen from Figures 1C and 1D, for 12 subcarriers, pairs of adjacent REs are grouped into 3 frequency-division multiplexing (FDM) groups. Thus, the 6 component sets are obtained from two FD-OCCs ({1,1} and {1,-1} both) applied to the 3 FDM groups respectively. In the case of 1-symbol DMRS (Figure 1C), each of the resulting 6 component sets can be assigned to up to 6 orthogonal DMRS ports. In the case of 2-symbol DMRS, these 6 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 Figures 1A - 1D, complex numbers, cyclic shifts, FD-OCCs, FDMs, and TD-OCCs constitute resource elements for reference signals, especially for front DMRS.

[0050] These resource elements are combined according to the first or second front DMRS configuration, and the resulting set of components or CDM group is assigned to an orthogonal DMRS port, respectively. However, the use of 2-symbol DMRS should enable lower ranks. In the case of 1-symbol or 2-symbol DMRS, not all of the sets of components or CDM groups supported by a particular configuration need to be used for port assignment. In particular, even in the case of 2 symbols, it should be possible to schedule 6 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 placed approximately in the same location.

[0052] There is still room for further study as to whether the UE front DMRS configuration types may be different in UL and DL. Further, a downselection may still be discussed if the above agreement involves significant complexity / performance issues.

[0053] LTE DMRS Configuration

[0054] The above DMRS configuration in 3GPP NR is different from that in LTE. In LTE, there is mainly a single downlink configuration that supports up to 8 orthogonal ports / layers using frequency and time code division multiplexing that uses Walsh-Hadamard orthogonal cover codes. The configuration and further details regarding the DMRS configuration in LTE can be found in Non-Patent Document 8.

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

[0056]

Table 1

[0057] In LTE, up to eight orthogonal DMRS ports are supported for the downlink, mainly using a single category of multiplexing scheme (time / frequency OCC). 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, the use of resources (DMRS overhead) is the same for any port combination.

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

[0059] As can be seen from Table 1, in LTE, the possible combinations in the mapping between layers and ports are very limited. A 4-bit bitmap is defined to inform a given user of the mapping between layers and ports. The minimum number of port combinations is supported for the layer-port mapping results under the following restrictions. For up to two layers, the port indexing of the mapping is continuous and there is no overlap. For three to eight layers, the indexing is continuous and there is no overlap, starting from index 0 as the fixed starting point. The mapping is limited to one port combination.

[0060] In the latest release of LTE, only transparent MU-MIMO (and not non-transparent MU-MIMO) is supported. However, this is not always 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 making one bit a dedicated power offset field. Nevertheless, support for non-transparent MU-MIMO for three or more UEs has never been agreed upon, and in particular, has not been agreed upon in more recent LTE releases. It was determined that the disadvantages of the increased signaling overhead would not outweigh the resulting benefits.

[0062] DMRS Requirements for NR

[0063] The limitations on the layer and port mapping of LTE can no longer be tolerated in 3GPP NR. In particular, there is a need for non-transparent MU-MIMO to benefit from the advantages of the new system design in 3GPP NR.

[0064] For example, the decision made for LTE that does not incorporate a dedicated bit field can be reconsidered in order to incorporate support for non-transparent MU-MIMO into 3GPP NR. However, currently, since there is a dedicated bit field for MU-MIMO, support is not necessary.

[0065] Description of Embodiments

[0066] The present disclosure promotes the signaling of cooperative scheduling information (non-transparent MU-MIMO) for each of the code division multiplexing (CDM) groups 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 combined information on layer and port mapping that is combined with cooperative scheduling information to promote a more efficient and effective signaling mechanism.

[0067] In the exemplary embodiment shown in FIG. 2, the present disclosure presents a mobile terminal 210 that transmits and / or receives data with a base station 260 that uses a plurality of antennas in a mobile communication system. The mobile terminal 210 and the base station 260 are configured to transmit and / or receive data via a radio channel 250.

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

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

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

[0071] In particular, the layer-port mapping varies according to the configurations of the base station 260 and the mobile terminal 210, i.e., according to 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 determines the maximum number of DMRS ports that can be scheduled by the base station 260.

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

[0073] For this purpose, the mobile terminal 210 comprises circuits such as, for example, the transceiver 220 and the processor 230, which, during operation, receive parameters that define a configuration for allocating each of the (time-frequency) resources carrying the reference signals to the DMRS ports. In other words, in this configuration, each of the reference signals of one or more DMRS ports is allocated to a specific resource, which may also be represented as a set of (resource) elements.

[0074] The resources or sets of (resource) elements are grouped into a plurality of code division multiplexing (CDM) groups. In particular, the code division multiplexing (CDM) groups specify, for each of the DMRS ports, the resources or sets of (resource) elements for carrying the reference signals such that each resource or set of (resource) elements can carry a maximum number of, for example, two or four orthogonal reference signals on each of the DMRS ports of the same CDM group.

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

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

[0077] As already described above, the (time-frequency) resources for carrying reference signals are grouped into a plurality of 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 an orthogonal cover code (OCD) or time and / or frequency code division multiplexing (CDM).

[0078] In the context of the present disclosure, CDM groups are referred to from the perspective of the mobile terminal 210. In the mobile terminal 210, a CDM group refers to a resource or set of (resource) elements of DMRS ports that are approximately located in the same place.

[0079] For an exemplary embodiment, the circuitry of the mobile terminal 210, such as the transceiver 220 and the processor 230, is applied during operation to receive control information indicating one of a set of combinations of layer and port mappings for placing a reference signal on at least one DMRS port of a CDM group for data transmission and / or reception.

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

[0081] However, the configuration parameters and the control information are not received simultaneously by the mobile terminal 210. Rather, the base station 260 can inform the configuration parameters only rarely, for example, by means of the radio resource control (RRC) protocol, whereas the control information can be informed via the physical downlink control channel (PDCCH) together with the scheduling information in the downlink control information (DCI).

[0082] Furthermore, for an exemplary embodiment, the received control information is not limited to merely indicating to the mobile terminal 210 one of a set of layer and port mapping configurations. Rather, the received control information further indicates cooperative scheduling information for each CDM group to the mobile terminal 210.

[0083] This cooperative scheduling information can then be used for the transmission and / or reception of the same data, i.e., for improving interference cancellation and / or rate matching for the transmission and / or reception of data in the same TTI.

[0084] When cooperative scheduling information is shown for each CDM group, a favorable trade-off for non-transparent MU-MIMO signaling is achieved. In particular, by showing cooperative scheduling for each CDM group, there is an advantage of minimizing signaling overhead with respect to improving interference cancellation and / or adapting rate matching to increase data transmission capacity.

[0085] In the following, a distinction is made between the indication of cooperative scheduling information to a CDM group (hereinafter represented as the first set of CDM groups) in which the mobile terminal 210 is scheduled to transmit and / or receive a reference signal and other CDM groups (represented as the second set of CDM groups) that are not scheduled for the mobile terminal 210. However, this distinction becomes clearer when considering the advantages obtained by the cooperative scheduling information.

[0086] As described above, the mobile terminal 210 can use the cooperative scheduling indication to improve interference cancellation.

[0087] In each CDM group, the base station cooperatively schedules different mobile terminals to allocate reference signals to the DMRS ports of the same resource (in the same CDM group). Although the DMRS ports are said to be orthogonal to each other within the CDM group, there may be a leakage phenomenon between the reference signals, and as a result, the reception quality of the reference signals may deteriorate. Therefore, due to this interference, the coherent demodulation ability of data transmission and / or reception will decrease.

[0088] Here, based on the additional cooperative scheduling information of the CDM group, the mobile station knows the cooperative scheduling of the CDM group, that is, the resource, which still carries its own reference signal. That is, with this additional cooperative scheduling information, the mobile station can perform interference cancellation on the reference signal, thereby improving the coherent demodulation ability.

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

[0090] Furthermore, the mobile terminal 210 can use the cooperative scheduling indication for improving the rate matching.

[0091] In each CDM group, the base station can schedule different mobile terminals to allocate reference signals to the DMRS ports of different resources (for example, of different CDM groups). The scheduling of the DMRS ports of different CDM groups is optimal for the interference characteristics of the CDM group, but this scheduling prevents the mobile terminal from reusing different resources (from the context) for data transmission and / or reception.

[0092] In other words, the mobile terminal is placed at a position where it can determine to allocate symbols for data transmission and / or reception to this (additional) different resource (of different CDM groups) based on the information about the (actual) allocation of the reference signal to different resources (of different CDM groups). This increases the data transmission capacity in each TTI, and therefore, it goes without saying that an adapted rate matching is required to utilize the increased data transmission capacity.

[0093] Here, based on the additional cooperative scheduling information of the CDM group, the mobile station knows the cooperative scheduling of another CDM group, that is, a resource, which does not carry its "own" reference signal. That is, based on this additional cooperative scheduling information, the mobile terminal can then determine whether it can reuse these resources from different CDM groups for data transmission and / or reception, but this reuse requires rate matching adapted according to the increase in data transmission capacity.

[0094] It should be noted that the improved rate matching for data transmission and / or reception in the same TTI is only related to the cooperative scheduling information in a separate CDM group (the second set of CDM groups) in which the mobile terminal is not scheduled to transmit and / or receive the reference signal.

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

[0096] Therefore, it has already become clear that, according to the present disclosure, indicating the cooperative scheduling information has already brought advantageous effects even if the cooperative scheduling information is only known for a subset rather than all of the plurality of CDM groups.

[0097] In the context of the present disclosure, the coordinated scheduling information is known for each CDM group. This coordinated scheduling information is to be understood as indicating to the mobile terminal that the base station is coordinately scheduling another mobile terminal to the DMRS ports of the respective resources of the CDM group for transmission and / or reception of reference signals.

[0098] For some CDM groups to which the coordinated scheduling information is provided, it may be advantageous to interpret the coordinated scheduling information separately.

[0099] Regarding the second set of CDM groups, the coordinated scheduling information enables the mobile terminal to adapt rate matching so as to benefit from an increase in data transmission capacity. Notably, all that is required of the mobile terminal to do so is to know whether (or not) there is at least one other mobile terminal assigned to the DMRS ports of another CDM group.

[0100] If there is at least one assigned DMRS port in one of the second set of CDM groups, then the transmission and / or reception of each reference signal is considered to be more important than the adaptation of rate matching and the benefit from the increase in data transmission capacity. Otherwise, the mobile terminal can adapt rate matching to utilize the increase in its data transmission capacity.

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

[0102] Regarding the first set of the CDM group, with the cooperative scheduling information, the mobile terminal can benefit from improved interference cancellation. However, the improvement of interference cancellation is only necessary when there are more mobile terminals, for example, more than one (e.g., two or three), than a given number (represented as number X in FIGS. 3 to 6) of different DMRS ports of the same CDM group in the first set.

[0103] Instead, when there are fewer mobile terminals, for example, one or none, to which different DMRS ports of the same CDM group in the first set are assigned, it can be fully expected that the existing mechanism is operating sufficiently to establish orthogonal DMRS ports.

[0104] For example, in the 3GPP NR deployment scenario, interference cancellation is improved by using a blind interference detection mechanism at the reference signal receiver. Thereby, even without any prior knowledge about the interference at the receiver (only the cooperative scheduling information indicates that there is interference from a given number of, for example, two or three mobile terminals), the improvement of the reception characteristics of the reference signal is achieved.

[0105] However, the blind interference detection mechanism is computationally complex, costly in terms of power consumption, and introduces a non-negligible processing delay into the signaling flow, so it is only beneficial when (actually) a large amount of interference is indicated. For this purpose, the number of cooperative scheduling interferences shown in the first set of the CDM group (represented as number X in FIGS. 3 to 6) is different from the number of cooperative scheduling interferences shown in the second set of the CDM group.

[0106] In other words, the interpretation of the cooperative scheduling information can be determined by the CDM group, and thus by the set of CDM groups to which the cooperative scheduling information is received. When the cooperative scheduling information is received for the CDM groups in the first set that carry their "own" reference signals, the cooperative scheduling information can indicate the presence of a given number of mobile terminals that are cooperatively scheduled for each CDM group compared to the second set of CMD groups. In this case, the cooperative scheduling information can indicate the presence of any mobile terminal that is cooperatively scheduled for each CDM group.

[0107] Similarly, the present disclosure also presents a base station 260 for transmitting and / or receiving data to and from a mobile terminal 210 that uses a plurality of antennas in a mobile communication system. Here too, the base station 260 and the mobile terminal 210 are configured to transmit and / or receive data via a radio channel 250.

[0108] The base station 260 includes a circuit such as a transceiver 270 and a processor 280, which, during operation, transmits parameters that define a configuration for assigning each resource grouped into a plurality of code division multiplexing (CDM) groups for carrying reference signals to ports towards the mobile terminal 210, and transmits control information indicating one of a set of combinations of layer and port mappings that is applied to place a reference signal at a port of at least one CDM group for data transmission and / or reception towards the mobile terminal 210.

[0109] In addition, here the control information also indicates cooperative scheduling information for 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.

[0110] Here, refer to the form in which control information is transmitted between the base station 260 and the mobile station 210. For this purpose, refer to FIGS. 3 to 6 as exemplary embodiments of the signaling mechanism.

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

[0112] In this regard, for example, a mobile terminal 210 that has received control information in binary format refers to the corresponding indexed row (in column 1 of each figure), and thus obtains the layer and port mapping indicated by the base station, as well as the cooperative scheduling information for each of the CDM groups. As can be seen from the figure, it has been proposed to give separate (multiple) rows with the same port and layer mapping in the control information in order to reflect all possible permutations of the cooperative scheduling information.

[0113] More specifically, FIG. 3 shows an exemplary set of combinations of layer and port mappings (columns 2 and 3) combined with cooperative scheduling information (columns 4 and 5) for each CDM group for DMRS configuration type 1 and 1-symbol DMRS configuration. Therefore, 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 for each of the two CDM groups.

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

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

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

[0117] For all of 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 assigned consecutive indexes, and the DMRS ports of the CDM groups are (also) assigned consecutive indexes, that is, thereby the indexes of the DMRS ports will increase together with the indexes of the multiple CDM groups.

[0119] In other words, considering a (single) CDM group, the indexes of the DMRS ports of this CDM group are distributed consecutively. This can already be inferred from the fact that each DMRS port of the CDM group is assigned a consecutive index regardless of the specific CDM group.

[0120] Considering another CDM group here, the indexes of the DMRS ports are distributed within the CDM group such that any one of the DMRS ports of a specific CDM group with a smaller index has a smaller index than any one of the DMRS ports of another specific CDM group with the next larger index.

[0121] Since the consecutive indexing of the CDM groups and the DMRS ports is defined, for the exemplary embodiments of FIGS. 3 to 6, it is also assumed that the base station is continuously and incrementally (i.e., sequentially) assigning the DMRS ports to the mobile station for all of the multiple CDM groups.

[0122] 2. The mobile terminal is assigned a DMRS port from among all of the multiple CDM groups having consecutive indexes starting from the DMRS port with the smallest index.

[0123] For the sake of discussion, assume that the base station 260 assigns to the mobile terminal 210 a DMRS port with the minimum index (DMRS port 0, i.e., P0). In this case, if the base station 260 wants to assign another DMRS port to the same mobile terminal 210, the base station must proceed to assign a DMRS port with the next larger consecutive index (DMRS port 1, i.e., P1). Therefore, it is not possible for one 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 signaling overhead in the control signal. 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. In MU-MIMO, the maximum number of DMRS ports that can be scheduled per mobile terminal is limited to a number smaller than a given number, for example, the maximum number of DMRS ports defined by a configuration for allocating respective resources to the 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, which indicates the mapping of layers and ports and the coordinated scheduling for each CDM group, decreases drastically.

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

[0128] In the latter case, from the mere fact that SU-MIMO is configured, there is no need to add and indicate 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 at all.

[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"). In the figure, although the maximum number of DMRS ports for each mobile terminal in MU-MIMO is 2, three DMRS ports (ports P0 to P2) or four DMRS ports (ports P0 to P4) are shown. Therefore, it can be seen that at the mobile terminal, data transmission and / or reception is being performed in SU-MIMO. That is, there is no cooperative scheduling, and thus the cooperative scheduling information becomes "0" in CDM group 0 and "0" in CDM group 1.

[0130] 4. In SU-MIMO, the maximum number of DMRS ports that can be scheduled for each mobile terminal is limited to a number smaller than a given number, for example, the maximum number of DMRS ports defined by a configuration for allocating respective resources to the ports.

[0131] By reducing the maximum number of DMRS ports for each mobile terminal in SU-MIMO, the total number of permutations reflected in the control information, which indicates cooperative scheduling for each of the layer and port mappings as well as the CDM groups, is further reduced.

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

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

[0134] 5. In a mobile terminal to which all DMRS ports of a (single) CDM group are assigned, no coordinated scheduling within the same CDM group is expected.

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

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

[0137] 6. A mobile terminal to which a DMRS port with the smallest index of a (single) CDM group is not assigned expects coordinated scheduling within the same CDM group and within CDM groups with smaller indices.

[0138] The signaling of this coordinated scheduling information to the CDM group utilizes the fact that the DMRS ports are assigned continuously and incrementally (as discussed in item 2 above).

[0139] For the sake of discussion, assume that the base station 260 allocates to the mobile terminal 210 a DMRS port with an intermediate index (DMRS port 1, i.e., P1), rather than the DMRS port with the minimum index (DMRS port 0, i.e., P0). In this case, since the base station 260 is required to allocate a DMRS port starting from the minimum index, the mobile terminal 210 can infer that a (different) co-scheduled mobile terminal is within the same CDM group to which the allocated DMRS port with index 1 belongs. Therefore, it is inherent that the co-scheduling information indicated by the control information in MU-MIMO is always "1" within the same CDM group.

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

[0141] This inherent signaling of the co-scheduling information applies not only to the CDM group to which the allocated DMRS port belongs, but also to CDM groups with smaller indices.

[0142] For discussion purposes, assume that the base station 260 assigns to the mobile terminal 210 a DMRS port with an intermediate index (DMRS port 3, i.e., P3) instead of the DMRS port with the minimum index (DMRS port 0, i.e., P0). In this case, since the base station 260 is required to assign DMRS ports starting from the minimum index, the mobile terminal 210 can infer that a coordinated-scheduled (another) 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, in MU-MIMO, the coordinated-scheduling information indicated for CDM group 0 and CDM group 1 by the control information is always "1".

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

[0144] The present disclosure can be implemented by software, hardware, or software combined with hardware. Each functional block used in the description of each of the above embodiments 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 a plurality of LSIs. The LSI can be formed individually as a chip, or one chip can be formed to include part or all of the functional blocks. The LSI can include a data input / output section coupled thereto. In this specification, the LSI may sometimes be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the difference in integration level.

[0145] However, the technique for implementing the integrated circuit is not limited to LSI, and may be realized using an application-specific circuit, a general-purpose processor, or a special-purpose processor. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI, or a reconfigurable processor that can reconfigure the connection and setting of the circuits arranged inside the LSI may also be used. The present disclosure can be realized as digital processing or analog processing. When future circuit technology replaces LSI as a result of the progress of semiconductor technology or other derivative technologies, the functional blocks can also be integrated using that future integrated circuit technology. Biotechnology can also be applied.

[0146] According to a first aspect, there is proposed a mobile terminal for transmitting and / or receiving data to / from a base station using a plurality of antennas within a layer in a mobile communication system, the mobile terminal receiving, during operation, from the base station parameters defining a configuration that assigns each resource grouped into a plurality of code division multiplexing (CDM) groups for carrying a reference signal to a port, and receiving from the base station control information indicating one of a set of combinations of layer and port mappings, which is applied to arrange the reference signal in at least one port 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 of the plurality of 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 the 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 within the at least one and / or another CDM group.

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

[0150] According to a fifth aspect that can be combined with the first to fourth aspects, the cooperative scheduling information is binary information indicating the presence or absence of cooperative scheduling in each of the plurality of CDM groups.

[0151] According to a sixth aspect that 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 a consecutive index such that the index of the port increases together with the index of the plurality of CDM groups.

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

[0153] According to an eighth aspect that can be combined with the first to seventh aspects, resources assigned to ports of CDM groups having an index smaller than the minimum index of the ports indicated by the control information for arranging the reference signal are known to be originally cooperatively scheduled by the base station.

[0154] According to a ninth aspect that can be combined with the first to eighth aspects, the mapping means indexing the combination of the layer and port mapping and the cooperative scheduling information.

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

[0156] According to an eleventh aspect that can be combined with the first to tenth aspects, the parameter that defines the configuration for allocating each resource for carrying a reference signal to a port is received via a radio resource control (RRC) protocol.

[0157] According to a twelfth aspect that can be combined with the first to eleventh aspects, the control information that indicates one of the sets of combinations of layer and port mappings and indicates the cooperative scheduling information is received via a physical downlink control channel (PDCCH).

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

[0159] According to a fourteenth aspect that can be combined with the first to thirteenth aspects, the mobile terminal further includes a transceiver that applies the indicated combination of layer and port mappings to perform data transmission and / or reception during operation.

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

[0161] According to a 16th aspect, a method performed by a mobile terminal for transmitting and / or receiving data in a layer to / from a base station using a plurality of antennas in a mobile communication system is proposed. The method includes receiving, from a base station, parameters defining a configuration that assigns each resource grouped into a plurality of code division multiplexing (CDM) groups for carrying a reference signal to a port, and receiving, from the base station, control information indicating one of a set of combinations of layer and port mappings applied to arrange the reference signal at a port of at least one CDM group for data transmission and / or reception, 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 the plurality of CDM groups for the same data transmission and / or reception.

[0162] According to a 17th aspect that can be combined with the 16th 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 that can be combined with the 16th or 17th aspect, the coordinated scheduling information indicates that the base station is coordinately scheduling different mobile terminals within the at least one and / or another CDM group.

[0164] According to a 19th aspect that can 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 within the at least one and / or another CDM group.

[0165] According to a 20th aspect that can be combined with the 16th to 19th aspects, the cooperative scheduling information is binary information indicating the presence or absence of cooperative scheduling in each of the plurality of CDM groups.

[0166] According to a 21st aspect that 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 a consecutive index such that the index of the port increases together with the index of the plurality of CDM groups.

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

[0168] According to a 23rd aspect that can be combined with the 16th to 22nd aspects, resources assigned 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 originally cooperatively scheduled by the base station.

[0169] According to a 24th aspect that can be combined with the 16th to 23rd aspects, the mapping means indexing the combination of the layer and port mapping and the cooperative scheduling information.

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

[0171] According to a 26th aspect that can be combined with the 16th to 25th aspects, parameters defining a configuration for allocating each resource for carrying a reference signal to a port are received via a radio resource control (RRC) protocol.

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

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

[0174] According to a 29th aspect that can be combined with the 16th to 28th aspects, the method further includes applying the indicated combination of layer and port mappings to perform the data transmission and / or reception.

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

[0176] According to a 31st aspect, a base station for transmitting and / or receiving data in a layer to and from a mobile terminal (210) using a plurality of antennas in a mobile communication system is proposed. The base station, during operation, transmits to the mobile terminal parameters defining a configuration that assigns each resource grouped into a plurality of code division multiplexing (CDM) groups for carrying a reference signal to a port, and transmits to the mobile terminal control information indicating one of a set of combinations of layer and port mappings that is applied to arrange the reference signal at a port of at least one CDM group for data transmission and / or reception. The control information additionally indicates cooperative scheduling information for the at least one CDM group and / or at least one other CDM group among the plurality of CDM groups for the same data transmission and / or reception.

[0177] According to a 32nd aspect, a method performed by a base station for transmitting and / or receiving data in a layer to and from a mobile terminal using a plurality of antennas in a mobile communication system is proposed. The method includes transmitting to the mobile terminal parameters defining a configuration that assigns each resource grouped into a plurality of code division multiplexing (CDM) groups for carrying a reference signal to a port, and transmitting to the mobile terminal control information indicating one of a set of combinations of layer and port mappings applied to arrange the reference signal at ports of at least one CDM group for data transmission and / or reception. The control information additionally indicates cooperative scheduling information for the at least one CDM group and / or at least one other CDM group among the plurality of CDM groups for the same data transmission and / or reception.

Claims

1. A mobile terminal, receiving parameters defining a configuration for allocating resources to a port for carrying reference signals, the resources being grouped into a number of code division multiplexing (CDM) groups; 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 data transmission and / or reception; the control information indicating coordinated scheduling information for the at least one CDM group and / or at least one other CDM group of a plurality of CDM groups for the same data transmission and / or reception. A circuit is provided. 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. Mobile terminal.

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

3. The coordinated scheduling information includes: 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: A mobile terminal according to claim 1 or 2.

4. the plurality of CDM groups are consecutively indexed, and the ports of each of the plurality of CDM groups are consecutively indexed such that the port index increases with the index of the plurality of CDM groups. A mobile terminal according to any one of claims 1 to 3.

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. A mobile terminal according to any one of claims 1 to 4.

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 configuring the reference signal are coordinated and scheduled by the base station. A mobile terminal according to any one of claims 1 to 5.

7. The mapping means indexing the layer / port mapping combination and the coordinated scheduling information. A mobile terminal according to any one of claims 1 to 6.

8. The parameters defining a configuration for allocating resources to ports for carrying reference signals are received 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 received via a physical downlink control channel (PDCCH); A mobile terminal according to any one of claims 1 to 7.

9. The reference signal is a forward demodulation reference signal. A mobile terminal according to any one of claims 1 to 8.

10. a transceiver that applies the indicated layer / port mapping combination to transmit and / or receive the data; and / or a processor for performing interference compensation for the received reference signal and / or rate matching for the data transmission and / or reception. A mobile terminal according to any one of claims 1 to 9.

11. 1. A method performed by a mobile terminal, comprising: receiving parameters defining a configuration for allocating resources to a port for carrying reference signals, the resources being grouped into a number of code division multiplexing (CDM) groups; 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 data transmission and / or reception; the control information additionally indicates coordinated scheduling information for the at least one CDM group and / or at least one other CDM group of a plurality of CDM groups for transmission and / or reception of the same data. 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 having even subcarrier indices; The second resource element configuration includes frequency division multiplexing and frequency division orthogonal cover code (OCC); and further receiving an indicator from a base station indicating whether the first resource element configuration or the second resource element configuration is being used. method.

12. The control information indicates coordinated scheduling information for all or a subset of the plurality of CDM groups. The method of claim 11.

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