Apparatus, method and computer program

Abstract

Embodiments of the present disclosure relate to apparatuses, methods, and computer programs. An apparatus is provided, comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: providing at least one reference signal to a user equipment, the at least one reference signal being associated with v layers, where v>1; receiving, from the user equipment, information related to grouping the v layers into g groups and an indication of a group quality associated with each of the g groups; and performing link adaptation based on the group quality and the information related to grouping the v layers into the g groups.

Description

Technical Field

[0001] Various embodiments of this disclosure generally relate to methods, apparatus, and computer programs, and particularly, but not exclusively, to flexible channel quality indicator (CQI) reporting with layer packet signaling. Background Technology

[0002] A communication system can be viewed as a facility that enables communication sessions between two or more communication devices or provides communication devices with access to a network. Mobile or wireless communication networks are an example of communication networks. Communication devices may be served by application servers.

[0003] Mobile or wireless communication networks can operate according to multiple standards, such as those provided by 3GPP (3rd Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of mobile or wireless communication networks operating according to 3GPP standards are often referred to as 4G (fourth generation) networks, 5G (fifth generation) networks, 5G Advanced networks, and 6G networks. Summary of the Invention

[0004] Some embodiments of this disclosure will be described with respect to certain aspects. These aspects are not intended to indicate key or essential features of the various exemplary embodiments of this disclosure, nor are they intended to limit its scope. Other features, aspects, and elements will be apparent to those skilled in the art in light of this disclosure. For example, it should be understood that additional aspects may be provided by any combination of any two or more of the aspects described herein.

[0005] In a first aspect, a method is provided, comprising receiving from a network at least one reference signal associated with v layers, wherein v > 1; determining channel quality for each of the v layers based on the received at least one reference signal; grouping the v layers into g groups based on the determined channel quality, wherein 2 ≤ g ≤ v - 1, wherein grouping the v layers into g groups comprises: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining layers in each of the g groups based on the sorting order of the v layers; determining group quality associated with each of the g groups; and providing the network with an indication of the group quality associated with each of the g groups, and information related to grouping the v layers into g groups.

[0006] This method may include providing information related to grouping v layers into g groups in the Media Access Control (MAC) control element (CE).

[0007] Information related to grouping v layers into g groups may include an indication of the sorting order.

[0008] Channel quality can include the signal-to-interference-noise ratio (SINR) or the channel quality indicator (CQI).

[0009] The method may include sorting the v layers into ascending or descending order based on the determined channel quality of the v layers.

[0010] The group quality associated with each of the g groups may include at least one of the following: the average value of the channel information for each layer in the layer of the group, the channel information with the highest value in the group, or the channel information with the lowest value in the group.

[0011] In a second aspect, a method is provided, comprising: providing a user equipment with at least one reference signal associated with v layers, wherein v > 1; receiving from the user equipment information relating to grouping the v layers into g groups and an indication of group quality associated with each of the g groups; and performing link adaptation based on the group quality and the information relating to grouping the v layers into g groups.

[0012] Performing link adaptation may include: determining a mapping between each of the v layers and one of the g groups, based at least on information related to grouping the v layers into g groups; determining modulation and coding scheme table entries based on the group quality associated with one of the g groups; and determining the number of layers to be transmitted and the modulation and coding scheme for each layer to be transmitted, based on the determined mapping and modulation and coding scheme table entries.

[0013] The method may include receiving information related to grouping v layers into g groups in the Media Access Control (MAC) control element (CE).

[0014] A method can be provided in the second aspect.

[0015] In a third aspect, an apparatus is provided, comprising components for performing the method according to the first or second aspect.

[0016] In a fourth aspect, an apparatus is provided, comprising at least one processor and at least one memory storing instructions, the instructions causing the apparatus to perform at least the method according to the first or second aspect when executed by the at least one processor.

[0017] In a fifth aspect, a non-transitory computer-readable medium comprising instructions, wherein when executed by at least one processor of the device, the device performs the method according to the first or second aspect.

[0018] In a sixth aspect, a computer program including instructions is provided that, when executed by a device, causes the device to perform at least the method according to the first or second aspect.

[0019] Some embodiments of the present invention are defined in the dependent claims.

[0020] Many different aspects have been described above. As previously stated, it should be understood that additional aspects may be provided by combination of any two or more of the above-described aspects (or otherwise in this disclosure).

[0021] Various other aspects are also described in the following detailed description and claims. Attached Figure Description

[0022] Some embodiments will be described by way of non-limiting and illustrative example only with reference to the accompanying drawings, wherein: Figure 1 An example of a communication network to which the examples disclosed herein can be applied is shown; Figure 2 A schematic diagram of CSI acquisition and CSI reporting is shown; Figure 3 A graph showing the calculation and dependencies of CSI parameters is provided. Figure 4 Examples of CQI and MCS tables used for PDSCH are shown; Figure 5 A graph showing the BLER performance in the presence of layer imbalance is presented; Figure 6 A diagram illustrating an example of a SINR imbalance scenario after equalization is shown. Figure 7 A flowchart of a method according to an example embodiment is shown; Figure 8 A flowchart of a method according to an example embodiment is shown; Figure 9 An example signaling flow between the UE and the gNB is shown; Figure 10 An example signaling flow between the UE and the gNB is shown; Figure 11 A flowchart of a method according to an example embodiment is shown; Figure 12 A flowchart of a method according to an example embodiment is shown; Figure 13 An example signaling flow between the UE and the gNB is shown; Figure 14 A diagram showing the possible partitions (groups) of a sorted LQI with stars and bars for (v, g)=(4, 2) is provided. Figure 15 A flowchart of an example embodiment is shown; Figure 16A flowchart of a method according to an example embodiment is shown; Figure 17 A flowchart of a method according to an example embodiment is shown; Figure 18 An example signaling flow between the UE and the gNB is shown; Figure 19 An example of layer grouping with v=4 is shown; Figure 20 A flowchart of an example embodiment is shown; Figure 21 An example of the device is shown. Detailed Implementation

[0023] The following embodiments are provided by way of non-limiting and illustrative example. Although the specification may refer to "a," "an," or "some" embodiments in several places in the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, such a feature, structure, or characteristic may be applied in conjunction with other embodiments (whether explicitly described or not).

[0024] It should be understood that although this document may use terms such as "first," "second," etc., to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0025] For the purposes of this disclosure, the phrases “at least one of A or B,” “at least one of A and B,” and “A and / or B” mean (A), (B), or (A and B). For the purposes of this disclosure, the phrases “A, B, and / or C” mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

[0026] As used herein, unless otherwise indicated (e.g., using “otherwise” or “or in the alternative”), the term “or” means non-exclusive “or”.

[0027] As used herein, unless explicitly stated otherwise, performing a feature, step, or function in response to A does not indicate that the feature, step, or function is performed immediately after A occurs, because one or more intervening features, steps, or functions may be performed (at least in part) between the occurrence of the feature, step, or function and A. Similarly, performing a feature, step, or function based on A does not indicate that the feature, step, or function is performed solely based on A, because the feature, step, or function may also be based on one or more other features, steps, or functions besides A.

[0028] The embodiments described herein can be implemented in communication networks such as any of the following radio access technologies (RATs): WiMAX, GSM (2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunications System based on Basic Wideband Code Division Multiple Access (W-CDMA) (UMTS, 3G), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), LTE Advanced and Enhanced LTE (eLTE), 5G (also known as NR), or any future RAT such as 6G. Furthermore, communication within the communication network can utilize any suitable wireless communication technology, including but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), and / or Discrete Fourier Transform Extended OFDM (DFT-s-OFDM).

[0029] As used herein, the term "network device" or "network node" refers to a node in a communications network through which user equipment can access the network and / or be configured to control radio communications and manage radio resources within a cell. A network node or network device may be referred to as a base station (BS), access point (AP), or access node. Depending on the technology applied, a network device may be, for example, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NR NB (also known as a gNB), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a repeater, an Integrated Access and Backhaul (IAB) node, a low-power node, a non-terrestrial network (NTN), or non-terrestrial network equipment such as satellite network equipment, low Earth orbit (LEO) satellites, and geostationary orbit (GEO) satellites or spacecraft network equipment.

[0030] Furthermore, in a split radio access network (RAN) connection, network equipment can refer to a centralized unit (CU) and / or a distributed unit (DU) of a base station. The interface between the CU and the DU can be referred to as the F1 interface in NR. In a split RAN architecture, node operations can be performed at least partially in a central / centralized unit (CU, e.g., a server, host, or node) that is operatively coupled to a DU (e.g., a radio head / node). A CU can control one or more DUs, at least acting as a transmit / receive (Tx / Rx) node. In some embodiments, a DU may include, for example, a Radio Link Control (RLC), a Media Access Control (MAC) layer, and a Physical (PHY) layer, while a CU may include layers above the RLC layer, such as a Packet Data Convergence Protocol (PDCP) layer, Radio Resource Control (RRC), and Internet Protocol (IP) layer. Other functional splitting is also possible. In practice, any processing task can be performed in a CU or a DU, and the boundaries of responsibility transfer between the CU and the DU can depend on the implementation applied.

[0031] The term "terminal device" refers to any terminal device that can be configured to perform wireless communication. For example, a terminal device can be referred to as a communication device, user equipment (UE), subscriber station (SS), or mobile station (MS). Terminal devices can include mobile phones, cellular phones, smartphones, Voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices (such as digital cameras), gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, USB dongles, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, and so on.

[0032] As used herein, the term "resource" can refer to radio resources in the time domain, frequency domain, spatial domain, and / or code domain. Some examples of resources may include, for example, physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency regions, subcarriers, beams, etc. The terms "transmit" and / or "receive" can refer to wirelessly transmitting and / or receiving on radio resources via a radio propagation channel.

[0033] Figure 1An example of a communication network to which the examples disclosed herein can be applied is shown. The communication network, or cellular communication network, may include a network node 110 configured to provide one or more cells (such as cell 100) and a network node 112 configured to provide one or more other cells (such as cell 102). Each cell may be, for example, a macrocell, microcell, femtocell, or picocell. A cell may define the coverage area or service area of ​​a corresponding access node.

[0034] Network nodes (110, 112) can be configured to provide radio access to a communication network to user equipment (UE) 120 (one or more UEs). Radio access may include downlink (DL) communication from network nodes (110, 112) to UE 120 and uplink (UL) communication from UE 120 to network nodes (110, 112). Examples of uplink channels may include a Physical Uplink Control Channel (PUCCH) for transmitting control information and a Physical Uplink Shared Channel (PUSCH) for transmitting data to the network. Examples of downlink channels may include a Physical Downlink Control Channel (PDCCH) for transmitting control information and a Physical Downlink Shared Channel (PDSCH) for transmitting data to the user equipment.

[0035] The system can have multiple UEs (120, 122). Each of the multiple UEs can be served by the same or different network nodes (110, 112). UEs can be configured with dual connectivity (DC), where a UE (e.g., UE 120) can connect to multiple network nodes (110, 112). UEs (120, 122) can communicate with each other when device-to-device (D2D) communication interfaces are established between them via so-called sidelinks (SL). For example, such D2D communication can be referred to as machine-to-machine, peer-to-peer (P2P) communication, or vehicle-to-vehicle (V2V) communication.

[0036] In a communication network with multiple network nodes, these nodes can connect to each other via interfaces. For example, the LTE specification refers to this interface as the X2 interface. The interface between an LTE node and a 5G node, or between two 5G nodes, can be called the Xn interface.

[0037] Network nodes 110 and 112 can also connect to the core network 116 of the communication network via another interface. The LTE specification designates the core network as the Evolved Packet Core (EPC), and the core network can include multiple entities (e.g., Mobility Management Entity (MME) and gateway nodes). The MME can handle the mobility of terminal devices in a tracking area covering multiple cells, as well as the signaling connections between the terminal devices and the core network. The gateway node can handle data routing within the core network and data routing to / from the terminal devices. The 5G specification designates the core network as the 5G Core (5GC). The 5GC can, for example, include Access and Mobility Management Functions (AMF) and User Plane Functions / Gateway (UPF) and other functions. The AMF can handle the termination of Non-Access Stratum (NAS) signaling, NAS encryption and integrity protection, registration management, connection management, mobility management, access authentication and authorization, and security context management. UPF nodes can, for example, support packet routing and forwarding, packet inspection, and Quality of Service (QoS) processing.

[0038] Currently, 3GPP specifications support up to eight layers in downlink (DL) multiple-input multiple-output (MIMO) communication. However, 5G devices may only support up to four layers in DL MIMO communication. The expected performance improvements in 5G compared to LTE may not be realized.

[0039] LTE supports the use of two codewords from layers 2 to 8. That is, for layer 4, LTE supports two codewords. The current 5G NR standard restricts PDSCH transmission to using only one codeword for a maximum of four layers, and two codewords only for layers 5 to 8. This is shown in Table 1 (taken from TS 38.211), where... It is the number of modulation symbols in the codeword, and It is the number of modulation symbols in each layer. Within four layers, only one codeword is supported, where all information bits are equally distributed across all layers.

[0040]

[0041] Table 1 In propagation environments where significant SINR imbalance occurs between MIMO layers, mapping a single codeword to up to four layers can negatively impact throughput performance. This imbalance can arise from the placement and directivity of the radio channel or UE antenna, resulting in varying gains for the gNodeB antenna. In the uplink, this imbalance can be further exacerbated by users partially obstructing the antenna when holding or changing the phone's orientation. Field measurements have recorded inter-layer SINR imbalances of 10 to 28 dB after equalization for four-layer transmission.

[0042] To adapt to real-time channel conditions, link adaptation can be employed, where the gNodeB dynamically adjusts DL transmission based on Channel State Information (CSI) measured and reported by the UE, such as... Figure 2 As shown. UE Channel State Information (CSI) feedback for 6G networks can be defined in 3GPP Release 21.

[0043] In such Figure 2 In the example shown, in step 1, the gNodeB transmits DL reference signals (RS), such as NZP CSI-RS (Non-Zero Power Channel State Information RS), for the UE to measure the radio channel and signal-to-interference-plus-noise ratio (SINR). In step 2, the UE uses these signals to obtain CSI parameters (RI, PMI, CQI), which are reported back to the gNodeB in step 3 as recommendations from the UE regarding the number of layers to be transmitted, precoder, and modulation and coding scheme (MCS) to maximize link capacity. In step 4, the gNodeB can use this information to adapt the PDSCH transmission configuration, ensuring that the connection is maintained despite transient changes in link conditions. Then, the gNodeB initiates PDSCH transmission in step 5.

[0044] In NR, the gNodeB can request reports from the UE regarding different combinations of CSI parameters (also known as CSI reporting quantities). This request is transmitted to the UE via higher-layer RRC signaling (e.g., CSI-ReportingConfig), one of the most common reporting quantities being "cri-RI-LI-PMI-CQI". Using this quantity, the UE is expected to report on CRI (CSI Resource Indicator), RI (Rank Indicator), LI (Layer Indicator), PMI (Precoding Matrix Indicator), and finally CQI (Channel Quality Indicator). While there are dependencies between these parameters, the specific implementation chosen can vary for each UE vendor.

[0045] Figure 3 An example of CSI parameter calculation and dependency for the reporting volume “cri-RI-LI-PMI-CQI” is shown. For instance, if multiple NZP CSI-RS resources exist, the UE will typically select the best resource for CRI based on the received signal strength of all resources. The UE will then obtain the channel estimate and SINR level for that NZP CSI-RS resource to select the optimal tier that maximizes link capacity. The number of layers is given by RI. Based on The UE will select the optimal precoder matrix, which is indicated by the PMI. ,in This is the total number of CSI-RS antenna ports, and The layer number is indicated by RI. For a combination of CRI, RI, and PMI, the UE calculates the SINR level for each MIMO layer and selects a CQI value to maximize the capacity of the entire layer against the target block error rate (BLER) (such as 0.1). This information is used to select the column (i.e., layer) of the strongest layer belonging to the codeword in the precoding matrix, indicated by LI (layer indicator).

[0046] For CQI calculation, the SINR level can be mapped, for example, to a CQI index value in a table, which is associated with the modulation scheme, code rate, and efficiency. In one example defined in TS 38.214, each CQI table has 16 different CQI indices, and there are 4 different CQI tables to support different scenarios of channel conditions and system configurations. Figure 4 Examples of CQI and MCS tables for PDSCH, as defined in TS 38.214, are shown, supporting up to 64 QAM modulation and providing a balance between data rate and robustness. Other available tables can support up to 256 QAM or even 1024 QAM modulation for applications with higher data rate targets at very high SINR conditions.

[0047] The gNB's MCS selection is based on an MCS table, similar to the CQI selection process. Each CQI table has a corresponding MCS table, and the gNodeB can use CQI indices to select the appropriate MCS value for a codeword. In the example, there are four MCS tables with 32 MCS indices, where the first 27 to 29 MCS indices represent different combinations of modulation order, target code rate, and spectral efficiency, such as... Figure 4 As seen in the image. The remaining MCS entries 28 / 30 to 32 (in...) Figure 4 (The numbers shown are reserved) are used to indicate the applicable modulation order for PDSCH retransmission, without any associated code rate or spectral efficiency.

[0048] If channel conditions are favorable, the gNB will select a higher CQI index, based on feedback from the UE. This may lead the gNodeB to select a higher MCS index for the codeword used in PDSCH MIMO transmission. Conversely, if channel conditions deteriorate and the SINR level decreases, the reported CQI index will be lower, and the gNodeB will select a lower MCS index for that codeword. However, due to other factors such as traffic load, service requirements, or any other aspect requiring optimization in the network, the gNodeB is free to select an MCS index different from the one suggested by the UE.

[0049] Because 5G NR has opted for a single codeword design for transmission across up to four layers, link adaptation performance becomes susceptible to the SINR of the weakest link in scenarios with SINR imbalance. If only one codeword is mapped to up to four layers, the MCS selection during link adaptation will be identical for all those layers. In layer-imbalanced scenarios, throughput performance may be limited by the equalized SINR of the weakest layer because the higher SINR of the strongest layer cannot be fully utilized when selecting a common MCS.

[0050] This is Figure 5 As shown, for a 2×2 MIMO scene in additive white Gaussian noise (AWGN), there is an artificial imbalance between the two layers. The middle curve shows the block error rate (BLER), where half the bits are transmitted through a high-quality channel with Eb / No+У, while the odd number of bits are transmitted through a low-quality channel with Eb / No-У. The right and left curves show the performance when all bits are transmitted through the low-quality channel and the high-quality channel, respectively. The ratio between these two channels indicates the imbalance.

[0051] In the presence of layer imbalance, the performance of low-density parity-check (LDPC) codes (middle curve) is significantly closer to the performance when all bits are transmitted through a low-quality channel (right curve), rather than the performance when all bits are transmitted through a high-quality channel (left curve). This illustrates that in layer imbalance scenarios, system performance is limited by the weakest layer. Even if some MIMO layers can provide better performance, they will transmit with a common and lower MCS, which is determined based on the measured SINR of all layers reported to the gNodeB via a single CQI feedback.

[0052] Performance can benefit from mapping more than one MCS or modulation order across the first four layers to help address layer imbalance. One way to achieve this is to associate each layer with its own codeword (e.g., a multi-codeword setup). This allows codewords in layers with lower SINR to choose a lower MCS, while codewords in unaffected layers can still utilize a higher MCS for better performance (e.g., realizing the throughput potential of MIMO transmissions). This would mean that in 6G systems, with variable modulation orders between layers and potentially different MCS for each layer, the UE would need to report an indicator of the equalized SINR for each layer, referred to hereinafter as the Layer Quality Indicator (LQI).

[0053] However, having such a multi-codeword setup may be impractical due to the increased overhead of DCI and CSI, which could become up to four times that of the current NR.

[0054] As is currently done in traditional NR, using a single quality layer indicator for up to four layers incurs minimal overhead, but makes system performance vulnerable in MIMO layer imbalance scenarios. Conversely, while providing layer quality information to the gNodeB for each layer could be an effective solution to layer imbalance, the resulting increased overhead makes it impractical. Nevertheless, MIMO SINR layer imbalance has proven to be a significant issue in 5G, and if resolved, it has the potential to significantly improve performance in 6G.

[0055] Figure 6 Examples of equalized SINR for three layers are shown in three scenarios, A, B, and C. In scenario A, the layers exhibit similar SINR levels and can be characterized by a single MCS / modulation order because layer imbalance is not significant. However, in scenarios B and C, if only one CQI is reported for all three layers, it will follow the SINR of the lower layers and therefore cannot properly utilize the higher quality of layer 1. Using a single MCS / modulation order can lead to lower-than-expected system performance. In other words, the SINR levels of the MIMO layers in scenarios B and C are sufficiently differentiated to guarantee reporting more than one CQI index value. While optimal accuracy would come from having a single CQI (baseline) for each layer, in both scenarios, having two of the three layers with closer SINR values, which can be represented by the same Layer Quality Indicator (LQI), has a smaller impact on performance.

[0056] The following method proposes that the UE group MIMO layers with similar equalized SINR levels and report the representative quality (e.g., LQI) of the group.

[0057] For example, assuming that the number of groups must be less than the number of layers to be grouped, the UE uses its available CSI information to dynamically determine how many layer groups to form and how to distribute the layers by each group.

[0058] This allows for a trade-off between the accuracy of quality recovery at each layer on the gNodeB side and the overhead required to report that information, resulting in a more flexible signaling framework, as shown in Table 2, that adapts to the current environment to maximize system performance.

[0059]

[0060] Table 2 Figure 7 This is a flowchart of a method according to an example embodiment. The method can be performed at a device. The device can be a user equipment or be included in or incorporated within a user equipment.

[0061] At 701, the method includes providing an instruction from the user equipment to the network, indicating that the user equipment is capable of grouping v layers into layer groups based on the channel quality for each layer and reporting information related to the grouping, where v > 1 and where the channel quality is determined at the user equipment based on a reference signal received from the network.

[0062] At 702, the method includes: in response, receiving a configuration of channel state information reports from the network, the configuration including an indication of the quality of reports per layer group, wherein the configuration of the channel information reports includes packet parameter information.

[0063] Figure 8 This is a flowchart of a method according to an example embodiment. The method can be performed at a device.

[0064] At 801, the method includes: receiving an indication from a user equipment that the user equipment is capable of grouping v layers into layer groups based on channel quality for each layer and reporting information related to the grouping, wherein v > 1 and wherein the channel quality is determined at the user equipment based on a reference signal received from the network.

[0065] At 802, the method includes: in response, providing the user equipment with a configuration for channel state information reporting, the configuration including an indication of group quality for reporting per layer group, wherein the configuration for channel information reporting includes group parameter information.

[0066] The channel quality for each layer can be referred to as LQI. Channel quality can include the signal-to-interference-to-noise ratio (SINR), such as equalized SINR or Channel Quality Indicator (CQI).

[0067] The group quality associated with each group can be referred to as the Layer Group Quality Indicator (LGQI). The group quality for each layer group, that is, the group quality associated with each group, can include at least one of the following: the average channel quality for each layer in the layer of the group, the channel quality with the highest value in the group, or the channel quality with the lowest value in the group.

[0068] The channel state information report can be configured to be received in a radio resource control message.

[0069] Indicators that allow a user equipment (UE) to group v layers into g layer groups based on the channel quality for each layer and to report the groups can include a Layer Grouping Capability Indicator (LGCI). The LGCI can indicate whether the UE can group layers and report CQI for each layer group.

[0070] Information related to grouping v layers into groups can be provided to the network in the Media Access Control (MAC) control element (CE). Further examples of information related to grouping v layers into layer groups are provided in the context of combining... Figures 11 to 20 The method described is given in the text.

[0071] Figure 9 It shows the reference Figure 7 and Figure 8 The described method includes example signaling stream signals between the UE and gNB.

[0072] In step 1, the UE establishes an RRC connection with the gNodeB.

[0073] In step 2, gNodeB sends a capability report request (or UE capability query) to the UE.

[0074] In step 3, in response to a UE capability query, the UE sends an RRC message reporting its capabilities, such as supported bandwidth, subcarrier spacing, modulation scheme, MIMO layer, etc. This existing message also includes a Layer Grouping Capability Indicator (LGCI) to indicate whether the UE can group layers and report CQI per layer group. This is an example of providing an indication from the user equipment to the network that the user equipment can group v layers into layer groups based on the channel quality for each layer and report the groups.

[0075] In step 4, using the higher-layer parameter CSI-ResourceConfig, gNodeB notifies the UE of the resource configuration for DL ​​CSI signaling (ZP CSI-RS, NZP CSI-RS, IM CSI-RS) and subsequent channel measurements.

[0076] In step 5, using the higher-layer parameter CSI-ReportConfig, the gNodeB will also notify the UE of the settings selected for CSI reporting, such as which CSI parameters to report, codebook configuration, frequency granularity for CQI and PMI, measurement limitations, etc. The gNB also requests the reporting quantity cri-RI-PMI-LGQI, which includes quality information for each layer group.

[0077] In step 6, gNodeB transmits the DL reference signal (RS) to the UE.

[0078] In step 7, the UE receives these signals and uses them for CSI acquisition. The UE decodes the RS and measures the equalized SINR for each layer. The UE can use this information to determine the number of groups g and / or how to group the v MIMO layers to calculate the Layer Quality per Group (LGQI). This grouping information may include the LGI. See below for reference. Figures 11 to 20 Further details are provided regarding the LGI example. Specifically, the UE groups the v layers into groups based on the channel quality determined at the UE. In step 8, the UE reports the LGQI and the remaining CSI parameters configured to be reported.

[0079] Packet-related information (such as LGI) can be transmitted at a lower frequency, for example, via dedicated MAC CE messages used for layer packets.

[0080] At step 9, the gNodeB uses LGI and LGQI to determine how to adapt the transmission by selecting the number of layer groups (codewords / modulation order per codeword), the number of layers, the optimal precoder for each layer group, and the optimal MCS / modulation order. This can be predefined, for example, via an optimized table. Further examples related to step 9 are combined below. Figures 11 to 14 as well as Figures 16 to 19 Please provide an explanation.

[0081] In step 10, the gNodeB informs the UE of decisions such as the number of layers to be transmitted, layer-to-codeword mapping, and MCS via the DCI carried by the PDCCH, so that the UE can correctly decode the received signal.

[0082] In step 11, the gNodeB uses the transmission parameters determined in step 9 to transmit PDSCH data to the UE.

[0083] Grouping parameter information can include the maximum value of g. For example, gNodeB can inform the UE of the maximum number of groups it can support, maxNbrGroup. This way, if the network load is too high, gNodeB can choose a smaller number, and the UE will be aware of the limitation. Choose to save resources used for data transfer, such as Figure 10 As shown in step 5, it corresponds to Figure 9 Example signaling flow.

[0084] In the example, the UE is not solely composed of... Instead of limiting, consider the requirements of gNodeB. For example, if maxNbrGroups is specified as 2 but... Then the maximum number of allowed groups will be 2 instead of 3. Conversely, if maxNbrGroups is 3 but If so, only one group can be formed. In other words:

[0085] In the example, the UEs will be based on their post-equalization SINR levels, as indicated by the RI. Each MIMO layer is organized into Within each group, the layers in the group will share similar SINR levels and therefore can be described by the same quality indicator without significant performance loss.

[0086] Once the UE has determined the MIMO layer groups, it reports the number of groups and related packet information to the gNodeB in the form of a Layer Group Indicator (LGI) field. This signaling exchange will let the gNodeB know which layers the UE recommends sharing the same MCS / modulation order.

[0087] All layers in the group will share the same Layer Group Quality Indicator (LGQI) value, and It carries the quality information of each group.

[0088] Different methods can be used to determine how many tier groups to form, as well as the tier grouping procedures and reports. Assuming the UE creates g non-empty tier groups, where each group can have a different size (number of tiers), two schemes are proposed for the grouping criteria. While the number of groups and the grouping criteria can be UE vendor-specific implementations, these two approaches can involve different CSI reporting schemes, which will be presented in more detail below.

[0089] The first approach can be referred to as sorted layer grouping and reporting. For example, grouping v layers into g groups may include: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining the layers in each of the g groups based on the sorting order of the v layers. In this example, the information associated with grouping the v layers into g groups may include an indication of the sorting order.

[0090] The second method can be referred to as unordered layer grouping and reporting. For example, grouping v layers into groups may include assigning the first layer to a first group, determining whether the channel quality of subsequent layers in the v layers is within the quality range of the channel quality of the first layer, and if so, assigning the subsequent layers in the v layers to the first group; otherwise, assigning the subsequent layers in the v layers to a second group. Grouping parameter information may include an indication of the quality range.

[0091] In the first method, layers are sorted in ascending or descending order based on a Layer Quality Indicator (LQI), which can be either the SINR after equalization for each layer or the CQI for each layer, and then partitioned. Layer group.

[0092] Figure 11 A flowchart illustrating a method according to an example is shown. This method can be performed at a device. The device can be a UE or include or be included in a UE.

[0093] At 1101, the method includes receiving at least one reference signal from the network, the at least one reference signal being associated with v layers, where v>1.

[0094] At 1102, the method includes determining the channel quality for each of the v layers based on at least one received reference signal.

[0095] At 1103, based on the determined channel quality, v layers are grouped into g groups, where 2 ≤ g ≤ v-1, wherein grouping v layers into g groups includes: sorting v layers into a sorting order based on the determined channel quality of v layers, and determining the layers in each of the g groups based on the sorting order of v layers.

[0096] At 1104, the method includes determining the group quality associated with each of the g groups.

[0097] At 1105, the method includes providing the network with an indication of the quality of the group associated with each of the g groups, as well as information related to grouping the v layers into the g groups.

[0098] Figure 12 A flowchart illustrating a method according to an example is shown. This method can be performed at a device. The device may include a radio access node, such as a gNB or RAN in a 6G network.

[0099] At 1201, the method includes providing at least one reference signal to a user equipment, the at least one reference signal being associated with v layers, where v>1.

[0100] At 1202, the method includes receiving from the user equipment information related to grouping v layers into g groups and an indication of the group quality associated with each of the g groups.

[0101] At 1203, the method includes performing link adaptation based on group quality and information related to grouping v layers into g groups.

[0102] The channel quality of each layer can also be referred to as LQI. Channel quality can be the signal-to-interference-to-noise ratio (SINR) (e.g., equalized SINR) or the channel quality indicator (CQI).

[0103] Figure 13 The use of reference is shown Figure 11 and 12 The described method is for example signaling flows fed back at each layer.

[0104] Steps 1 to 6 are as per the reference. Figure 9 As stated above.

[0105] For reference Figure 11 The described method may include sorting the v layers in ascending or descending order based on the determined channel quality. Figure 13At step 7.2.0, the UE obtains the LQI for each layer and sorts the layers in ascending (increasing) or descending (decreasing) order. This is an example of receiving at least one reference signal from the network associated with v layers, where v ≥ 1, and determining the channel quality for each of the v layers based on at least one received reference signal.

[0106] In step 7.2.1, the UE is determined. Regarding the number of groups formed. The decision reflects a trade-off between the average variance of LQI per group and the number of groups. For example, if the number of groups equals the number of strata, the average variance of LQI per group will be zero because each group will have only one LQI, but the number of groups will be maximized, thus increasing reporting overhead. On the other hand, if the number of groups is only 1, the average variance of LQI per group will be maximized because there is only one group. Therefore, in one example, the maximum number of groups is between 1 and... Between (obtained during CSI acquisition in step 7.1) ), and select To minimize the average variance of LQI for each group.

[0107] In step 7.2.2, the UE determines the layer groups. This is an example of grouping v layers into g groups, where 2 ≤ g ≤ v⁻¹. In this example, grouping v layers into g groups includes: sorting the v layers according to their determined channel quality, and determining the layers within each of the g groups based on their sorting order. These layers can be sorted in ascending or descending order.

[0108] Grouping can be achieved using stars and bars, a combinatorial mathematical theorem that allows objects (stars) to be divided using separators (bars). In this case, the stars are the sorted SINR values ​​for each layer, while the bars are used to create layer groups, such as... Figure 14 As shown, for = (4,2) and has an increasing order.

[0109] In the example, assuming there are v MIMO layers, the UE has already decided... There are 3 groups, each containing at least one layer, and the LQIs are ordered in ascending or descending order. The number of possible layer groupings (LGs) following the "star and bar" theorem is given by the following formula:

[0110] for Figure 14The example in the table shows 4 layers and 2 groups, with a total of 3 grouping options. The number of possible grouping combinations for each (v, g) pair is shown in Table 3, which illustrates the number of layer-to-group mapping combinations using Method 1 for each (v, g) pair. For example, for... = There will only be two possibilities. And for one of them... In any given situation, there is only one possible grouping. If multiple possible grouping options exist, the UE can choose the grouping option that minimizes the average variance of the LQI per group.

[0111]

[0112] Table 3 and The group quality (e.g., LGQI) associated with each group can include at least one of the following: the average value of the channel information for each layer in the group, the channel information with the highest value in the group, or the channel information with the lowest value in the group.

[0113] For example, in Figure 13 In step 7.2.3, once groups are formed, an LQI is assigned to each group to be reported back to gNodeB. The LQI can be, for example, the average LQI across the layers of the group, or the LQI of the strongest or weakest layer.

[0114] Information related to grouping v layers into g groups can be provided to the network in the Media Access Control (MAC) control element (CE).

[0115] For example, in Figure 13 In step 8, the UE transmits information related to grouping v layers into g groups (or layer grouping information) to the gNodeB via dedicated MAC CE signaling, and transmits an indication of the group quality associated with each of the g groups (or per-layer group quality information) via regular CSI reports.

[0116] Layer grouping information is used to inform gNodeB how to sort the layers (e.g., in...). Figure 13 In step 7.2.0), how many groups were formed? (For example, in) Figure 13 In step 7.2.1), how many layers to group into and how the layers are distributed within the groups (e.g., in...). Figure 13 (In step 7.2.2).

[0117] Layer grouping information may include a Layer Grouping Indicator (LGI). The LGI indicates how layers are distributed across groups. The LGI can be an index based on the definition in Table 3, indicating to the UE for a specific... The chosen layer distribution is combined. Several methods exist to encode LG table entries to minimize the required number of bits. For example, due to... The gNodeB has already been informed through the CSI report, therefore it will take a maximum of [time / percentage]. LGI is encoded using 3 bits. Assuming LQI is always quantized using 4 bits, gNodeB can also infer it from LGQI. Therefore, LGI overhead can be further reduced to 2 bits.

[0118] Layer grouping information may include a Layer Ordering Indicator (LSI). The LSI indicates how layers are ordered. The LGI informs the gNodeB of the number of groups and the number of layers per group, but does not specify a particular layer-to-group mapping. Therefore, the UE indicates how to order layers via the LSI.

[0119] For a maximum of 4 layers, there will be 4! possible sorted sequences, where the sorting can be identified using unique sequence pairs: one for ascending and the other for descending. This potential ambiguity (ascending or descending) can be eliminated by gNodeB when examining its LQI sequence. Therefore, LSI requires a total of log2(4! / 2) = 4 bits.

[0120] Layer grouping information (such as LGI and LSI) can be transmitted less frequently than CSI reports. For example, LGI and LSI MACCE messages will always be sent along with CSI report messages, but MAC CE transmissions will only be triggered at the UE when the layer order and / or optimal grouping changes. Otherwise, the gNodeB should continue to assume that the layer grouping is the same as the last reported one. Field measurements indicate that changes in layer order and imbalance occur more slowly than the periodicity of CSI reports, typically configured between 4 and 640 slots (0.5 ms to 80 ms at a 30 kHz subcarrier spacing), therefore layer grouping information does not need to be reported as frequently as CSI information.

[0121] Indications for the group quality associated with g groups (e.g., LQI values ​​for each tier group) can be provided in a parameter called the Tier Group Quality Indicator (LGQI). For example, each group has its own LQI, and a quantized version of the group's representative LQI will occupy 4 bits, as in a traditional 5G NR CQI report. The LGQI field will contain this information for all groups and will be sent periodically along with other CSI reporting parameters (CRI, RI, PMI), totaling 4 bits. ×4 bits.

[0122] In summary, the UE provides three parameters to the gNB: LGI, LSI, and LGQI. Table 4 shows example formats of these parameters that can be transmitted to the gNodeB via signaling, and the overhead required to transmit them for the available v-1 grouping options in a v=4 scenario. If all 4 layers are in a single group (g=1), the LGQI will consist of a single 4-bit LQI (as in legacy 5G NR) and 3 bits of LGI information on the MAC CE. The LSI field in the MAC CE message will be omitted because the gNodeB does not need to know the ordering within a single group.

[0123]

[0124] Table 4 Performing link adaptation may include: determining a mapping between each of the v layers and one of the g groups, based at least on information related to grouping the v layers into g groups; determining modulation and coding scheme table entries based on the group quality associated with one of the g groups; and determining the number of layers to be transmitted and the modulation and coding scheme for each layer to be transmitted, based on the determined mapping and modulation and coding scheme table entries.

[0125] For example, when gNodeB is in Figure 13 When the latest CSI report is received in step 8, it begins decoding its contents in step 9 to select the optimal MCS / modulation order for each layer. Figure 15 A flowchart showing how step 9 will occur on the gNodeB side is shown, focusing specifically on the MCS selection process under this new proposal.

[0126] In the example, during link adaptation, the gNodeB will periodically receive CSI reports containing information such as CRI, RI, PMI, and LGQI. This CSI report may be accompanied by LGI and LSI MAC CEs, sent whenever new information about the packet to be reported is available. If a new MAC CE message and a new CSI report are received, the gNodeB will collect and store the new LGI and LSI information. Otherwise, if no new MAC CE message arrives with a new CSI report, the gNodeB should assume the same packet information as the last reported packet. The gNodeB will recover v from RI and g from LGQI, which is found in the received CSI report (assuming each group's LQI has a fixed bit length of 4 bits). This information, along with the LGI and LSI, is used to recover layer-to-group mapping information. Figure 15Step 9.1 in [the document]. This is an example where, based on information relevant to grouping the v layers into g groups, the mapping between each of the v layers and one of the g groups is determined. Once known, gNodeB maps each LQI carried in the LGQI field to each layer group ([the document continues with steps 9.1]). Figure 15 Step 9.2 in the table), and mapping each LQI to an entry in the MCS table ( Figure 15 (Step 9.3 in the document). This is an example of determining modulation and decoding scheme table entries based on the group quality associated with one of the g groups.

[0127] The gNodeB uses this information to determine how many groups (codewords or modulation order per codeword) to form in the next PDSCH transmission, how many layers to transmit, the layer-to-group mapping, and the MCS / modulation order per group (step 9.4). Here is an example where, based on the determined mapping and modulation coding scheme table entries, the number of layers to transmit and the modulation coding scheme for each layer to be transmitted are determined.

[0128] Figure 16 A flowchart illustrating a method according to an example is shown. This method can be performed at a device. The device can be a UE or include or be included in a UE.

[0129] At 1601, the method includes receiving at least one reference signal from the network, the at least one reference signal being associated with v layers, where v>1.

[0130] At 1602, the method includes determining the channel quality for each of the v layers based on at least one received reference signal.

[0131] At 1603, the method includes grouping v layers into groups based on determined channel quality, wherein grouping v layers into groups includes assigning a first layer to a first group, determining whether the channel quality of subsequent layers in the v layers is within the quality range of the determined channel quality of the first layer in the first group, and if so, assigning subsequent layers in the v layers to the first group, and if not, assigning subsequent layers in the v layers to a second group, wherein the first layer in the v layers and the subsequent layers in the v layers are determined according to a layer sequence.

[0132] At 1604, the method includes determining the group quality associated with each group in the group.

[0133] At 1605, the method includes providing the network with an indication of the quality of the group associated with each group in the group, as well as information related to grouping v layers into groups.

[0134] Figure 17A flowchart illustrating a method according to an example is shown. This method can be performed at a device. The device can be, include, or be included in an access node of a network, such as a gNB or a 6G network access node.

[0135] At 1701, at least one reference signal is provided to the user equipment, the at least one reference signal being associated with v layers, where v>1.

[0136] At 1702, the method includes receiving from the user equipment information related to grouping v layers into groups and an indication of the group quality associated with each group in the group.

[0137] At 1703, the method includes performing link adaptation based on group quality and information related to grouping v layers into groups.

[0138] The second group can be the group whose range is closest to the LQI value of one of the subsequent layers in the v layers, or it can be an empty group if no such group exists. These groups can be called bins.

[0139] The layer sequence can include the order of the spatial components of the precoding matrix.

[0140] Channel quality for each layer can also be referred to as LQI. Channel quality can be the signal-to-interference-to-noise ratio (SINR) (e.g., equalized SINR) or the channel quality indicator (CQI).

[0141] Figure 18 The signaling flow according to an example embodiment is shown.

[0142] Steps 1 to 6 are as per the reference. Figure 9 As stated above.

[0143] In step 7.1, the number of groups is calculated through a layer grouping process. Assume there are... Each layer, such as the index of each PMI, is defined. A grouping rule is proposed, where: i. Start with v-1 empty separation bins.

[0144] ii. The LQI of layer 1 is always placed in the first bin (group 1). This is an example of assigning the first layer to the first group.

[0145] iii. The LQI of each layer in subsequent layers will be assigned to the respective bins in the same order as the PMI index, based on the agreed LQI range: If the LQI of a new layer falls within the LQI range of an already assigned layer, it should be placed in the same bin. Here's an example where the channel quality of a subsequent layer out of v layers is determined to be within the quality range of the determined channel quality of the first layer in the first group, and that subsequent layer is assigned to the first group.

[0146] If a new LQI does not fall within the range of any assigned layer, it should be placed in the next empty bin. If no more empty bins are available, the layer must be assigned to the bin with the range closest to the LQI value. Here is an example where it is determined that the channel quality of a subsequent layer out of v layers is outside the range of the determined channel quality of the first layer in the first group, and that subsequent layer is assigned to the second group.

[0147] iv. At the end of the process, k empty bins (if any) are discarded, and thus the number of groups is given by the following formula:

[0148] This process is in Figure 19 China targeted one of them The scenario is shown. Because only one of the three boxes... Each bin remains empty, therefore the number of layers created is Group 1 (sub-box 1) has layer 1 and layer 2, and group 2 (sub-box 2) has layer 3 and layer 4.

[0149] After applying the grouping rules, the resulting layer-to-group mapping is identified (reported later in step 8) by matching it against a set of predefined layer-to-group mapping options. These options correspond to specific... The minimum number of unique set partitions for each pair, assuming no empty groups and that the number of groups does not exceed the number of levels, is shown in Table 5. For optimality, these numbers cannot be further reduced without introducing ambiguity in the level-to-group mapping; this table has been constructed according to the following rules: The first column elements are... Give All diagonal elements Depend on (This will be removed later because it will force g) <v)。

[0150] The elements of the triangle are given inductively as follows:

[0151]

[0152] Table 5 Information related to grouping v layers into g groups can be provided to the network in the Media Access Control (MAC) control element (CE).

[0153] For example, in Figure 18 In step 8, the UE transmits information related to grouping v layers into groups (or layer grouping information) to the gNodeB via dedicated MAC CE signaling, and transmits group quality indications (or per-layer group quality information) associated with each group via regular CSI reports.

[0154] Indications of group quality associated with g groups (e.g., LQI values ​​for each tier group) can be provided in a parameter called the Tier Group Quality Indicator (LGQI). For example, each group has its own LQI, and a quantized version of the group's representative LQI will occupy 4 bits, as in a traditional 5G NR CQI report. The LGQI field will contain this information for all groups and will be sent periodically along with other CSI reporting parameters (CRI, RI, PMI), totaling 4 bits. ×4 bits. The group quality (e.g., LGQI) associated with each group may include at least one of the following: the average value of the channel information for each layer in the layers of the group, the channel information with the highest value in the group, or the channel information with the lowest value in the group.

[0155] The information relating to grouping the v layers into groups can be called layer grouping information. Layer grouping information can indicate to gNodeB how many groups have been formed. (exist Figure 18 In step 7.2.1), how many layers need to be grouped and how the layers are distributed within the groups (in... Figure 18 (In step 7.2.2).

[0156] Layer grouping information may include a Layer Grouping Indicator (LGI). The LGI can be based on an index defined in Table 5. The LGI can instruct the UE to target specific... Combine the selected layer distribution.

[0157] Layer grouping information (such as LGI and LSI) can be transmitted less frequently than CSI reports. For example, MAC CE messages for LGI and LSI will always be sent along with CSI report messages, but the transmission of MAC CE is only triggered when the UE has a layer ordering and / or the optimal grouping changes. Otherwise, the gNodeB should continue to assume that the layer grouping is the same as the previously reported one. and The RI and LGQI can be obtained from the CSI report, respectively. The LGI encoding requires at most [number missing]. 3 bits.

[0158] In summary, this example provides two parameters, LGI and LGQI. Table 6 shows example formats for signaling these new parameters to the gNodeB, and... In the available scenarios Each group option transmits the overhead required for it. Note that if In this case, the MAC CE message will not be triggered, because there is no need to report any layer-to-group mapping information.

[0159]

[0160] Table 6 In step 9, when the gNodeB receives the latest CSI report, it begins decoding its contents to select the optimal MCS / modulation order for each layer. Figure 20 An example flowchart is shown showing how step 9 will occur on the gNodeB side, focusing specifically on the MCS selection process under this new proposal.

[0161] In the example, during link adaptation, the gNodeB will periodically receive CSI reports containing information such as CRI, RI, PMI, and LGQI. This CSI report may be accompanied by an LGI MAC CE and is sent whenever new information about the packet to be reported (and the number of groups exceeds one). If a new MAC CE message is received along with a new CSI report, the gNodeB will collect the new LGI information and store it. Otherwise, if no new MAC CE message arrives with a new CSI report, the gNodeB should assume the same packet information as the last reported packet. The gNodeB will recover v from RI and g from LGQI, which was found in the received CSI report (assuming each group's LQI has a fixed bit length of 4 bits). If no new MAC CE message is received, and the LQI now occupies only 4 bits in the latest CSI report, the UE should update its packet information to reflect this. This information, along with LGI, is used to recover layer-to-group mapping information. Figure 20 Step 9.1 in [the document]. This is an example where, based on at least information related to grouping v layers into groups, the mapping between each of the v layers and a group within the group is determined. Once known, gNodeB maps each LQI carried in the LGQI field to each layer group ([the document continues with steps 9.1]). Figure 20 Step 9.2 in the table), and mapping each LQI to an entry in the MCS table ( Figure 20 (Step 9.3 in the table). This is an example of determining modulation and decoding scheme table entries based on the group quality associated with a group in the group.

[0162] The gNodeB uses this information to determine how many groups (codewords or modulation order per codeword) to transmit in the next PDSCH transmission, how many layers to send, the layer-to-group mapping, and the MCS / modulation order per group. Figure 20 (Step 9.4 in the table). This is an example of determining the number of layers to be transmitted and the modulation and codec scheme for each layer to be transmitted based on the determined mapping and modulation and codec scheme table entries.

[0163] gNB can use groups in different ways.

[0164] For example, a multi-codeword setting where each group corresponds to a codeword (layers with the same codeword share the same modulation and coding rates, and the same MCS) or a single codeword setting where all groups share the same coding rate, but each layer group can have its own modulation order, which would require changing the MCS table in 3GPP.

[0165] The described method enables quality reporting per layer to improve performance in SINR layer imbalance scenarios while maintaining manageable signaling overhead.

[0166] The approach described above can provide a new CSI feedback signaling framework for 6G, which allows the UE to dynamically group layers based on the SINR imbalance after layer equalization, and instead assigns a quality indicator per layer group, thereby providing a trade-off between performance improvements and signaling overhead.

[0167] Figure 21 A block diagram of apparatus 10 is shown by way of example. Apparatus 10 includes, for example, at least one processor 12 and at least one memory 14 storing instructions 15, which, when executed by the at least one processor, cause apparatus 10 to perform at least one or more methods (or portions thereof) and any of the embodiments (or corresponding portions thereof) disclosed herein. In the example, at least one memory and instructions (e.g., computer program code, software) are configured, together with at least one processor, to cause apparatus 10 to perform one or more methods (or portions thereof) and any of the embodiments (or corresponding portions thereof) disclosed herein.

[0168] The processor 12 may include, or be configured as, one or more circuit systems configured to perform phases of the methods according to the embodiments described herein.

[0169] As used herein, the term "circuit system" may refer to one or more of the following: (a) a hardware circuit implementation only (such as an implementation in analog and / or digital circuits only) and (b) a combination of hardware circuits and software, such as (if applicable): (i) a combination of (multiple) analog and / or digital hardware circuits with software / firmware and (ii) any portion of (multiple) hardware processors having software (including (multiple) digital signal processors), software, and (multiple) memories, which work together to enable a device (such as a user equipment) to perform various functions and (c) (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or portions of (multiple) microprocessors, which require software (e.g., firmware) to operate, but may be absent when the software is not required to operate. The definition of circuit system applies to all uses of the term herein, including any claim. As yet another example, as used herein, the term circuit system also covers an implementation of hardware circuits or processors only (or multiple processors) or a portion of hardware circuits or processors and their accompanying software and / or firmware. The term "circuit system" also covers, for example (and if applicable to certain claim elements), baseband integrated circuits or processor integrated circuits for mobile devices or similar integrated circuits in servers, cellular network devices or other computing or networking devices.

[0170] The memory 14 can be implemented using any suitable data storage technology. The memory may include a database for storing data. The memory 14 may be, for example, at least partially external to the device 10, but accessible to the device 10.

[0171] Instruction 15 may be included in a computer-readable medium or a non-transitory computer-readable medium. As used herein, the term non-transitory refers to a limitation on the medium itself (i.e., tangible, not signaling), rather than a limitation on the persistence of data storage (e.g., random access memory RAM versus read-only memory ROM).

[0172] For example, device 10 is a terminal device, such as a UE. As another example, the device is included in such a terminal device, for example, as a chipset configured to control the terminal device. Device 10 can be caused or configured to perform at least... Figure 7 , 11 Methods 16 and / or any one or more embodiments described herein, or including methods for performing at least Figure 7 , 11 The methods of 16 and / or components of any one or more embodiments described herein.

[0173] For example, device 10 can be a network node, such as a base station. As another example, the device is included in a node, such as a chipset configured as a control node. Device 10 can be made or configured to perform at least... Figure 8 , 12 Methods of 17 and / or any one or more embodiments described herein, or including methods for performing at least Figure 8 , 12 The methods of 17 and / or components of any one or more embodiments described herein.

[0174] Device 10 includes a radio interface 16. The radio interface 16 can provide communication capabilities to device 10. The radio interface 16 may include a receiver configured to receive information according to at least one cellular or non-cellular standard. The radio interface 16 may include a transmitter configured to transmit information according to at least one cellular or non-cellular standard. The receiver may include more than one receiver. The transmitter may include more than one transmitter. The radio interface 16 may include a transceiver configured to receive and transmit information according to at least one cellular or non-cellular standard. The transceiver may include more than one transceiver.

[0175] Device 10 may include a user interface 18, which includes at least one of, for example, a keypad, microphone, touch display, monitor, speaker, etc. User interface 18 can be used to control the device by a user. User interface 18 may be external to device 10. For example, device 10 may be connected to another device, such as a computer, via a wireless or wired connection, and device 10 may be controlled by a user via the computer.

[0176] In embodiments, at least some of the processes described herein may be performed by an apparatus comprising components for performing at least some of the described processes. Components for performing the method steps disclosed herein may include software and / or hardware components of apparatus 10. For example, at least one processor 12, memory 14, and computer program code form components for performing one or more methods (or portions thereof) disclosed herein, and any embodiments (or corresponding portions thereof). As used herein, the term “component” is interpreted in the singular (i.e., referring to a single element) or the plural (i.e., referring to a combination of single elements). Thus, the term “component for [performing A, B, C]” is interpreted to encompass an apparatus in which only one component for performing A, B, and C is present, or an apparatus in which multiple components are present respectively for performing A, B, and C, or an apparatus in which partial or completely overlapping components for performing A, B, and C are present. Furthermore, the terms "component for performing A, component for performing B, component for performing C" should be interpreted as covering an apparatus in which only one component for performing A, B, and C exists, or an apparatus in which components for performing A, B, and C exist respectively, or an apparatus in which some or all overlapping components for performing A, B, and C exist.

[0177] Although this disclosure has been described above with reference to non-limiting and illustrative examples based on the accompanying drawings, it is clear that the scope of this disclosure is not limited thereto, but can be modified in many different ways. As technology advances, those skilled in the art will understand that this disclosure can also be implemented and / or modified in various ways. Furthermore, it will be clear to those skilled in the art that the embodiments described herein can, but are not necessarily, combined with other embodiments described herein in various ways.

[0178] Furthermore, various implementations of this disclosure can be described with reference to the following entries, and their features can be combined in any reasonable manner.

[0179] Item 1. An apparatus comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to at least: receive at least one reference signal from a network, the at least one reference signal being associated with v layers, wherein v > 1; determine channel quality for each of the v layers based on the received at least one reference signal; group the v layers into g groups based on the determined channel quality, wherein 2 ≤ g ≤ v - 1, wherein grouping the v layers into g groups comprises: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining layers in each of the g groups based on the sorting order of the v layers; determining group quality associated with each of the g groups; and providing the network with an indication of the group quality associated with each of the g groups, and information related to grouping the v layers into g groups.

[0180] Item 2. The apparatus according to Item 1 causes the execution to provide information related to grouping v layers into g groups in the Media Access Control (MAC) control element CE.

[0181] Item 3. The apparatus according to Item 1 or 2, wherein the information relating to grouping v layers into g groups includes an indication of the sorting order.

[0182] Item 4. An apparatus according to any one of items 1 to 3, wherein channel quality includes signal-to-interference-noise ratio (SINR) or channel quality indicator (CQI).

[0183] Item 5. An apparatus according to any one of items 1 to 4, such that the v layers are sorted into ascending or descending order based on the determined channel quality of the v layers.

[0184] Item 6. An apparatus according to any one of items 1 to 5, wherein the group quality associated with each of the g groups includes at least one of the following: the average channel quality of each layer in the layer of the group, the channel quality with the highest value in the group, or the channel quality with the lowest value in the group.

[0185] Item 7. An apparatus comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to at least: provide at least one reference signal to a user equipment, the at least one reference signal being associated with v layers, wherein v > 1; receive from the user equipment information relating to grouping the v layers into g groups and an indication of group quality associated with each of the g groups; and perform link adaptation based on the group quality and the information relating to grouping the v layers into g groups.

[0186] Item 8. The apparatus according to Item 7, wherein performing link adaptation includes: determining a mapping between each of the v layers and one of the g groups based at least on information relating to grouping the v layers into g groups; determining a modulation and coding scheme table entry based on the group quality associated with one of the g groups; and determining the number of layers to be transmitted and the modulation and coding scheme for each layer to be transmitted based on the determined mapping and modulation and coding scheme table entry.

[0187] Item 9. The apparatus according to Item 7 or Item 8 causes the execution to receive information relating to grouping v layers into g groups in the Media Access Control (MAC) control element CE.

[0188] Item 10. A method comprising: receiving from a network at least one reference signal, the at least one reference signal being associated with v layers, wherein v > 1; determining channel quality for each of the v layers based on the received at least one reference signal; grouping the v layers into g groups based on the determined channel quality, wherein 2 ≤ g ≤ v - 1, wherein grouping the v layers into g groups comprises: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining layers in each of the g groups based on the sorting order of the v layers; determining group quality associated with each of the g groups; and providing to the network an indication of the group quality associated with each of the g groups, and information relating to grouping the v layers into g groups.

[0189] Item 11. A method comprising: providing a user equipment with at least one reference signal, the at least one reference signal being associated with v layers, wherein v > 1; receiving from the user equipment information relating to grouping the v layers into g groups and an indication of group quality associated with each of the g groups; and performing link adaptation based on the group quality and the information relating to grouping the v layers into g groups.

[0190] Item 12. An apparatus comprising: receiving from a network at least one reference signal, the at least one reference signal being associated with v layers, wherein v > 1; determining channel quality for each of the v layers based on the received at least one reference signal; grouping the v layers into g groups based on the determined channel quality, wherein 2 ≤ g ≤ v - 1, wherein grouping the v layers into g groups comprises: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining layers in each of the g groups based on the sorting order of the v layers; determining group quality associated with each of the g groups; and providing to the network an indication of the group quality associated with each of the g groups, and information relating to grouping the v layers into g groups.

[0191] Item 13. An apparatus comprising: providing at least one reference signal to a user equipment, the at least one reference signal being associated with v layers, wherein v > 1; receiving from the user equipment information relating to grouping the v layers into g groups and an indication of group quality associated with each of the g groups; and performing link adaptation based on the group quality and the information relating to grouping the v layers into g groups.

[0192] Item 14. A computer program comprising instructions that, when executed by a means, cause the means to: receive from a network at least one reference signal, the at least one reference signal being associated with v layers, wherein v > 1; determine channel quality for each of the v layers based on the received at least one reference signal; group the v layers into g groups based on the determined channel quality, wherein 2 ≤ g ≤ v - 1, wherein grouping the v layers into g groups comprises: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining layers in each of the g groups based on the sorting order of the v layers; determining group quality associated with each of the g groups; and providing the network with an indication of the group quality associated with each of the g groups, and information relating to grouping the v layers into g groups.

[0193] Item 15. A computer program comprising instructions that, when executed by a device, cause the device to: provide at least one reference signal to a user equipment, the at least one reference signal being associated with v layers, wherein v > 1; receive from the user equipment information relating to grouping the v layers into g groups and an indication of group quality associated with each of the g groups; and perform link adaptation based on the group quality and the information relating to grouping the v layers into g groups.

Claims

1. An apparatus for communication, comprising at least one processor and at least one memory storing instructions, the instructions causing the apparatus to perform at least the following when executed by the at least one processor: Receive at least one reference signal from the network, the at least one reference signal being associated with v layers, where v > 1; Based on the received at least one reference signal, determine the channel quality for each of the v layers; Based on the determined channel quality, the v layers are grouped into g groups, where 2 ≤ g ≤ v-1, wherein grouping the v layers into g groups includes: The v layers are sorted into a sorting order based on the determined channel quality of the v layers, and the layers in each of the g groups are determined based on the sorting order of the v layers; Determine the group quality associated with each of the g groups; as well as Provide the network with an indication of the quality of the group associated with each of the g groups, as well as information related to grouping the v layers into the g groups.

2. The apparatus of claim 1, wherein the information relating to grouping the v layers into g groups is provided in the Media Access Control (MAC) control element CE.

3. The apparatus of claim 1 or 2, wherein the information relating to grouping the v layers into g groups includes an indication of the sorting order.

4. The apparatus according to claim 1 or 2, wherein channel quality includes signal-to-interference-noise ratio (SINR) or channel quality indicator (CQI).

5. The apparatus according to claim 1 or 2, wherein the process of sorting the v layers into ascending or descending order is performed based on the determined channel quality of the v layers.

6. The apparatus of claim 1 or 2, wherein the group quality associated with each of the g groups includes at least one of the following: the average channel quality for each layer of the group, the channel quality having the highest value in the group, or the channel quality having the lowest value in the group.

7. An apparatus for communication, comprising at least one processor and at least one memory storing instructions, the instructions causing the apparatus to perform at least the following when executed by the at least one processor: Provide at least one reference signal to the user equipment, the at least one reference signal being associated with v layers, where v>1; Receive from the user equipment information related to grouping the v layers into g groups and an indication of the group quality associated with each of the g groups; and Link adaptation is performed based on the group quality and the information related to grouping the v layers into g groups.

8. The apparatus of claim 7, wherein the execution link adaptation comprises: Based at least on the information relating to grouping the v layers into g groups, determine the mapping between each of the v layers and one of the g groups; Based on the group quality associated with one of the g groups, determine the modulation and coding scheme table entries; as well as Based on the determined mapping and the modulation and coding scheme table entries, the number of layers to be transmitted and the modulation and coding scheme for each layer to be transmitted are determined.

9. The apparatus of claim 7 or claim 8, wherein the receiving of the information relating to grouping the v layers into g groups is performed in the Media Access Control (MAC) control element CE.

10. A method for communication, comprising: Receive at least one reference signal from the network, the at least one reference signal being associated with v layers, where v > 1; Based on the received at least one reference signal, determine the channel quality for each of the v layers; Based on the determined channel quality, the v layers are grouped into g groups, where 2≤g≤v-1, wherein grouping the v layers into g groups includes: sorting the v layers into a sorting order based on the determined channel quality of the v layers, and determining the layers in each of the g groups based on the sorting order of the v layers; Determine the group quality associated with each of the g groups; and Provide the network with an indication of the quality of the group associated with each of the g groups, as well as information related to grouping the v layers into the g groups.

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