Patent Application
20240340669
The present disclosure relates to a wireless communication system, and in more detail, relates to a method and an apparatus of transmitting and receiving channel state information in a wireless communication system.
A mobile communication system has been developed to provide a voice service while guaranteeing mobility of users. However, a mobile communication system has extended even to a data service as well as a voice service, and currently, an explosive traffic increase has caused shortage of resources and users have demanded a faster service, so a more advanced mobile communication system has been required.
The requirements of a next-generation mobile communication system at large should be able to support accommodation of explosive data traffic, a remarkable increase in a transmission rate per user, accommodation of the significantly increased number of connected devices, very low End-to-End latency and high energy efficiency. To this end, a variety of technologies such as Dual Connectivity, Massive Multiple Input Multiple Output (Massive MIMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), Super wideband Support, Device Networking, etc. have been researched.
A technical object of the present disclosure is to provide a method and an apparatus for transmitting and receiving channel state information.
In addition, an additional technical object of the present disclosure is to provide a method and an apparatus for transmitting/receiving channel state information for channel state information reference signals (CSI-RSs) transmitted from multiple transmission reception points (TRPs).
The technical objects to be achieved by the present disclosure are not limited to the above-described technical objects, and other technical objects which are not described herein will be clearly understood by those skilled in the pertinent art from the following description.
A method of transmitting channel state information (CSI) in a wireless communication system according to an aspect of the present disclosure may include: receiving, from a base station, first configuration information related to CSI reporting and second configuration information related to a CSI resource, wherein the second configuration information includes information on one or more CSI resource sets associated with the first configuration information; receiving, from the base station, a CSI-reference signal (CSI-RS) on a plurality of CSI resources of the one or more CSI resource sets based on the second configuration information; receiving, from the base station, downlink control information (DCI) triggering to report CSI; and transmitting, to the base station, the CSI based on the DCI and the first configuration information. All or part of the plurality of CSI-RS resources may be configure with one or more resource pairs, and based on being configured to report a concatenated channel for each of the one or more resource pairs being by the first configuration information, for the CSI, at least one of i) a minimum time (Z) from reception of the DCI to transmission of the CSI, ii) a minimum time (Z′) from reception of the CSI-RS to transmission of the CSI may be determined to be a value greater than CSI without a concatenated channel.
A method of receiving channel state information (CSI) according to an additional aspect of the present disclosure may include: transmitting, to a user equipment (UE), first configuration information related to CSI reporting and second configuration information related to a CSI resource, wherein the second configuration information includes information on one or more CSI resource sets associated with the first configuration information; transmitting, to the UE, a CSI-reference signal (CSI-RS) on a plurality of CSI resources of the one or more CSI resource sets based on the second configuration information; transmitting, to the UE, downlink control information (DCI) triggering to report CSI; and receiving, from the UE, the CSI based on the DCI and the first configuration information. All or part of the plurality of CSI-RS resources may be configure with one or more resource pairs, and based on being configured to report a concatenated channel for each of the one or more resource pairs being by the first configuration information, for the CSI, at least one of i) a minimum time (Z) from reception of the DCI to transmission of the CSI, ii) a minimum time (Z′) from reception of the CSI-RS to transmission of the CSI may be determined to be a value greater than CSI without a concatenated channel.
According to an embodiment of the present disclosure, optimum channel state information for performing transmission of multiple TRPs (transmission reception point) may be acquired/reported.
In addition, according to an embodiment of the present disclosure, as optimum channel state information for performing transmission of multiple TRPs (transmission reception point) is acquired/reported, more suitable link adaptation may be performed.
In addition, according to an embodiment of the present disclosure, when a coherent joint transmission (CJT) scheme for multiple TRPs is used, the efficiency of a UE can be increased by reducing the implementation complexity of the UE by reducing the CJT channel state information (CSI) calculation time.
Effects achievable by the present disclosure are not limited to the above-described effects, and other effects which are not described herein may be clearly understood by those skilled in the pertinent art from the following description.
Accompanying drawings included as part of detailed description for understanding the present disclosure provide embodiments of the present disclosure and describe technical features of the present disclosure with detailed description.
Hereinafter, embodiments according to the present disclosure will be described in detail by referring to accompanying drawings. Detailed description to be disclosed with accompanying drawings is to describe exemplary embodiments of the present disclosure and is not to represent the only embodiment that the present disclosure may be implemented. The following detailed description includes specific details to provide complete understanding of the present disclosure. However, those skilled in the pertinent art knows that the present disclosure may be implemented without such specific details.
In some cases, known structures and devices may be omitted or may be shown in a form of a block diagram based on a core function of each structure and device in order to prevent a concept of the present disclosure from being ambiguous.
In the present disclosure, when an element is referred to as being “connected”, “combined” or “linked” to another element, it may include an indirect connection relation that yet another element presents therebetween as well as a direct connection relation. In addition, in the present disclosure, a term, “include” or “have”, specifies the presence of a mentioned feature, step, operation, component and/or element, but it does not exclude the presence or addition of one or more other features, stages, operations, components, elements and/or their groups.
In the present disclosure, a term such as “first”, “second”, etc. is used only to distinguish one element from other element and is not used to limit elements, and unless otherwise specified, it does not limit an order or importance, etc. between elements. Accordingly, within a scope of the present disclosure, a first element in an embodiment may be referred to as a second element in another embodiment and likewise, a second element in an embodiment may be referred to as a first element in another embodiment.
A term used in the present disclosure is to describe a specific embodiment, and is not to limit a claim. As used in a described and attached claim of an embodiment, a singular form is intended to include a plural form, unless the context clearly indicates otherwise. A term used in the present disclosure, “and/or”, may refer to one of related enumerated items or it means that it refers to and includes any and all possible combinations of two or more of them. In addition, “/” between words in the present disclosure has the same meaning as “and/or”, unless otherwise described.
The present disclosure describes a wireless communication network or a wireless communication system, and an operation performed in a wireless communication network may be performed in a process in which a device (e.g., a base station) controlling a corresponding wireless communication network controls a network and transmits or receives a signal, or may be performed in a process in which a terminal associated to a corresponding wireless network transmits or receives a signal with a network or between terminals.
In the present disclosure, transmitting or receiving a channel includes a meaning of transmitting or receiving information or a signal through a corresponding channel. For example, transmitting a control channel means that control information or a control signal is transmitted through a control channel. Similarly, transmitting a data channel means that data information or a data signal is transmitted through a data channel.
Hereinafter, a downlink (DL) means a communication from a base station to a terminal and an uplink (UL) means a communication from a terminal to a base station. In a downlink, a transmitter may be part of a base station and a receiver may be part of a terminal. In an uplink, a transmitter may be part of a terminal and a receiver may be part of a base station. A base station may be expressed as a first communication device and a terminal may be expressed as a second communication device. A base station (BS) may be substituted with a term such as a fixed station, a Node B, an eNB (evolved-NodeB), a gNB (Next Generation NodeB), a BTS (base transceiver system), an Access Point (AP), a Network (5G network), an AI (Artificial Intelligence) system/module, an RSU (road side unit), a robot, a drone (UAV: Unmanned Aerial Vehicle), an AR (Augmented Reality) device, a VR (Virtual Reality) device, etc. In addition, a terminal may be fixed or mobile, and may be substituted with a term such as a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), an MTC (Machine-Type Communication) device, an M2M (Machine-to-Machine) device, a D2D (Device-to-Device) device, a vehicle, an RSU (road side unit), a robot, an AI (Artificial Intelligence) module, a drone (UAV: Unmanned Aerial Vehicle), an AR (Augmented Reality) device, a VR (Virtual Reality) device, etc.
The following description may be used for a variety of radio access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. CDMA may be implemented by a wireless technology such as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA may be implemented by a radio technology such as GSM (Global System for Mobile communications)/GPRS (General Packet Radio Service)/EDGE (Enhanced Data Rates for GSM Evolution). OFDMA may be implemented by a radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (Evolved UTRA), etc. UTRA is a part of a UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of an E-UMTS (Evolved UMTS) using E-UTRA and LTE-A (Advanced)/LTE-A pro is an advanced version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an advanced version of 3GPP LTE/LTE-A/LTE-A pro.
To clarify description, it is described based on a 3GPP communication system (e.g., LTE-A, NR), but a technical idea of the present disclosure is not limited thereto. LTE means a technology after 3GPP TS (Technical Specification) 36.xxx Release 8. In detail, an LTE technology in or after 3GPP TS 36.xxx Release 10 is referred to as LTE-A and an LTE technology in or after 3GPP TS 36.xxx Release 13 is referred to as LTE-A pro. 3GPP NR means a technology in or after TS 38.xxx Release 15. LTE/NR may be referred to as a 3GPP system. “xxx” means a detailed number for a standard document. LTE/NR may be commonly referred to as a 3GPP system. For a background art, a term, an abbreviation, etc. used to describe the present disclosure, matters described in a standard document disclosed before the present disclosure may be referred to. For example, the following document may be referred to.
For 3GPP LTE, TS 36.211 (physical channels and modulation), TS 36.212 (multiplexing and channel coding), TS 36.213 (physical layer procedures), TS 36.300 (overall description), TS 36.331 (radio resource control) may be referred to.
For 3GPP NR, TS 38.211 (physical channels and modulation), TS 38.212 (multiplexing and channel coding), TS 38.213 (physical layer procedures for control), TS 38.214 (physical layer procedures for data), TS 38.300 (NR and NG-RAN (New Generation-Radio Access Network) overall description), TS 38.331 (radio resource control protocol specification) may be referred to.
Abbreviations of terms which may be used in the present disclosure is defined as follows.
As more communication devices have required a higher capacity, a need for an improved mobile broadband communication compared to the existing radio access technology (RAT) has emerged. In addition, massive MTC (Machine Type Communications) providing a variety of services anytime and anywhere by connecting a plurality of devices and things is also one of main issues which will be considered in a next-generation communication. Furthermore, a communication system design considering a service/a terminal sensitive to reliability and latency is also discussed. As such, introduction of a next-generation RAT considering eMBB (enhanced mobile broadband communication), mMTC (massive MTC), URLLC (Ultra-Reliable and Low Latency Communication), etc. is discussed and, for convenience, a corresponding technology is referred to as NR in the present disclosure. NR is an expression which represents an example of a 5G RAT.
A new RAT system including NR uses an OFDM transmission method or a transmission method similar to it. A new RAT system may follow OFDM parameters different from OFDM parameters of LTE. Alternatively, a new RAT system follows a numerology of the existing LTE/LTE-A as it is, but may support a wider system bandwidth (e.g., 100 MHz). Alternatively, one cell may support a plurality of numerologies. In other words, terminals which operate in accordance with different numerologies may coexist in one cell.
A numerology corresponds to one subcarrier spacing in a frequency domain. As a reference subcarrier spacing is scaled by an integer N, a different numerology may be defined.
In reference to
A NR system may support a plurality of numerologies. Here, a numerology may be defined by a subcarrier spacing and a cyclic prefix (CP) overhead. Here, a plurality of subcarrier spacings may be derived by scaling a basic (reference) subcarrier spacing by an integer N (or, μ). In addition, although it is assumed that a very low subcarrier spacing is not used in a very high carrier frequency, a used numerology may be selected independently from a frequency band. In addition, a variety of frame structures according to a plurality of numerologies may be supported in a NR system.
Hereinafter, an OFDM numerology and frame structure which may be considered in a NR system will be described. A plurality of OFDM numerologies supported in a NR system may be defined as in the following Table 1.
NR supports a plurality of numerologies (or subcarrier spacings (SCS)) for supporting a variety of 5G services. For example, when a SCS is 15 kHz, a wide area in traditional cellular bands is supported, and when a SCS is 30 kHz/60 kHz, dense-urban, lower latency and a wider carrier bandwidth are supported, and when a SCS is 60 kHz or higher, a bandwidth wider than 24.25 GHz is supported to overcome a phase noise.
An NR frequency band is defined as a frequency range in two types (FR1, FR2). FR1, FR2 may be configured as in the following Table 2. In addition, FR2 may mean a millimeter wave (mmW).
Regarding a frame structure in an NR system, a size of a variety of fields in a time domain is expresses as a multiple of a time unit of Tc=1/(Δfmax·Nf). Here, Δfmax is 480·103 Hz and Nf is 4096. Downlink and uplink transmission is configured (organized) with a radio frame having a duration of Tf=1/(ΔfmaxNf/100)·Tc=10 ms. Here, a radio frame is configured with 10 subframes having a duration of Tsf=(ΔfmaxNf/1000)·Tc=1 ms, respectively. In this case, there may be one set of frames for an uplink and one set of frames for a downlink. In addition, transmission in an uplink frame No. i from a terminal should start earlier by TTA=(NTA+NTA,offset) Tc than a corresponding downlink frame in a corresponding terminal starts. For a subcarrier spacing configuration μ, slots are numbered in an increasing order of nsμ ∈{0, . . . , Nslotsubframe,μ−1} in a subframe and are numbered in an increasing order of ns,fμ∈{0, . . . , Nslotframe,μ−1} in a radio frame. One slot is configured with Nsymbslot consecutive OFDM symbols and Nsymbslot is determined according to CP. A start of a slot nsμ in a subframe is temporally arranged with a start of an OFDM symbol nsμNsymbslot in the same subframe. All terminals may not perform transmission and reception at the same time, which means that all OFDM symbols of a downlink slot or an uplink slot may not be used.
Table 3 represents the number of OFDM symbols per slot (Nsymbslot), the number of slots per radio frame (Nslotframe,μ) and the number of slots per subframe (Nslotsubframe,μ) in a normal CP and Table 4 represents the number of OFDM symbols per slot, the number of slots per radio frame and the number of slots per subframe in an extended CP.
Regarding a physical resource in a NR system, an antenna port, a resource grid, a resource element, a resource block, a carrier part, etc. may be considered. Hereinafter, the physical resources which may be considered in an NR system will be described in detail.
First, in relation to an antenna port, an antenna port is defined so that a channel where a symbol in an antenna port is carried can be inferred from a channel where other symbol in the same antenna port is carried. When a large-scale property of a channel where a symbol in one antenna port is carried may be inferred from a channel where a symbol in other antenna port is carried, it may be said that 2 antenna ports are in a QC/QCL (quasi co-located or quasi co-location) relationship. In this case, the large-scale property includes at least one of delay spread, doppler spread, frequency shift, average received power, received timing.
In reference to
Point A plays a role as a common reference point of a resource block grid and is obtained as follows.
Common resource blocks are numbered from 0 to the top in a frequency domain for a subcarrier spacing configuration μ. The center of subcarrier 0 of common resource block 0 for a subcarrier spacing configuration μ is identical to ‘point A’. A relationship between a common resource block number nCRBμ and a resource element (k,l) for a subcarrier spacing configuration μ in a frequency domain is given as in the following Equation 1.
In Equation 1, k is defined relatively to point A so that k=0 corresponds to a subcarrier centering in point A. Physical resource blocks are numbered from 0 to NBWP,isize,μ−1 in a bandwidth part (BWP) and i is a number of a BWP. A relationship between a physical resource block nPRB and a common resource block nCRB in BWP i is given by the following Equation 2.
NBWP,istart,μ is a common resource block that a BWP starts relatively to common resource block 0.
In reference to
A carrier includes a plurality of subcarriers in a frequency domain. An RB (Resource Block) is defined as a plurality of (e.g., 12) consecutive subcarriers in a frequency domain. A BWP (Bandwidth Part) is defined as a plurality of consecutive (physical) resource blocks in a frequency domain and may correspond to one numerology (e.g., an SCS, a CP length, etc.). A carrier may include a maximum N (e.g., 5) BWPs. A data communication may be performed through an activated BWP and only one BWP may be activated for one terminal. In a resource grid, each element is referred to as a resource element (RE) and one complex symbol may be mapped.
In an NR system, up to 400 MHz may be supported per component carrier (CC). If a terminal operating in such a wideband CC always operates turning on a radio frequency (FR) chip for the whole CC, terminal battery consumption may increase. Alternatively, when several application cases operating in one wideband CC (e.g., eMBB, URLLC, Mmtc, V2X, etc.) are considered, a different numerology (e.g., a subcarrier spacing, etc.) may be supported per frequency band in a corresponding CC. Alternatively, each terminal may have a different capability for the maximum bandwidth. By considering it, a base station may indicate a terminal to operate only in a partial bandwidth, not in a full bandwidth of a wideband CC, and a corresponding partial bandwidth is defined as a bandwidth part (BWP) for convenience. A BWP may be configured with consecutive RBs on a frequency axis and may correspond to one numerology (e.g., a subcarrier spacing, a CP length, a slot/a mini-slot duration).
Meanwhile, a base station may configure a plurality of BWPs even in one CC configured to a terminal. For example, a BWP occupying a relatively small frequency domain may be configured in a PDCCH monitoring slot, and a PDSCH indicated by a PDCCH may be scheduled in a greater BWP. Alternatively, when UEs are congested in a specific BWP, some terminals may be configured with other BWP for load balancing. Alternatively, considering frequency domain inter-cell interference cancellation between neighboring cells, etc., some middle spectrums of a full bandwidth may be excluded and BWPs on both edges may be configured in the same slot. In other words, a base station may configure at least one DL/UL BWP to a terminal associated with a wideband CC. A base station may activate at least one DL/UL BWP of configured DL/UL BWP(s) at a specific time (by L1 signaling or MAC CE (Control Element) or RRC signaling, etc.). In addition, a base station may indicate switching to other configured DL/UL BWP (by L1 signaling or MAC CE or RRC signaling, etc.). Alternatively, based on a timer, when a timer value is expired, it may be switched to a determined DL/UL BWP. Here, an activated DL/UL BWP is defined as an active DL/UL BWP. But, a configuration on a DL/UL BWP may not be received when a terminal performs an initial access procedure or before a RRC connection is set up, so a DL/UL BWP which is assumed by a terminal under these situations is defined as an initial active DL/UL BWP.
In a wireless communication system, a terminal receives information through a downlink from a base station and transmits information through an uplink to a base station. Information transmitted and received by a base station and a terminal includes data and a variety of control information and a variety of physical channels exist according to a type/a usage of information transmitted and received by them.
When a terminal is turned on or newly enters a cell, it performs an initial cell search including synchronization with a base station or the like (S601). For the initial cell search, a terminal may synchronize with a base station by receiving a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from a base station and obtain information such as a cell identifier (ID), etc. After that, a terminal may obtain broadcasting information in a cell by receiving a physical broadcast channel (PBCH) from a base station. Meanwhile, a terminal may check out a downlink channel state by receiving a downlink reference signal (DL RS) at an initial cell search stage.
A terminal which completed an initial cell search may obtain more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) according to information carried in the PDCCH (S602).
Meanwhile, when a terminal accesses to a base station for the first time or does not have a radio resource for signal transmission, it may perform a random access (RACH) procedure to a base station (S603 to S606). For the random access procedure, a terminal may transmit a specific sequence as a preamble through a physical random access channel (PRACH) (S603 and S605) and may receive a response message for a preamble through a PDCCH and a corresponding PDSCH (S604 and S606). A contention based RACH may additionally perform a contention resolution procedure.
A terminal which performed the above-described procedure subsequently may perform PDCCH/PDSCH reception (S607) and PUSCH (Physical Uplink Shared
Channel)/PUCCH (physical uplink control channel) transmission (S608) as a general uplink/downlink signal transmission procedure. In particular, a terminal receives downlink control information (DCI) through a PDCCH. Here, DCI includes control information such as resource allocation information for a terminal and a format varies depending on its purpose of use.
Meanwhile, control information which is transmitted by a terminal to a base station through an uplink or is received by a terminal from a base station includes a downlink/uplink ACK/NACK (Acknowledgement/Non-Acknowledgement) signal, a CQI (Channel Quality Indicator), a PMI (Precoding Matrix Indicator), a RI (Rank Indicator), etc. For a 3GPP LTE system, a terminal may transmit control information of the above-described CQI/PMI/RI, etc. through a PUSCH and/or a PUCCH.
Table 5 represents an example of a DCI format in an NR system.
In reference to Table 5, DCI formats 0_0, 0_1 and 0_2 may include resource information (e.g., UL/SUL (Supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), information related to a transport block (TB) (e.g., MCS (Modulation Coding and Scheme), a NDI (New Data Indicator), a RV (Redundancy Version), etc.), information related to a HARQ (Hybrid-Automatic Repeat and request) (e.g., a process number, a DAI (Downlink Assignment Index), PDSCH-HARQ feedback timing, etc.), information related to multiple antennas (e.g., DMRS sequence initialization information, an antenna port, a CSI request, etc.), power control information (e.g., PUSCH power control, etc.) related to scheduling of a PUSCH and control information included in each DCI format may be pre-defined.
DCI format 0_0 is used for scheduling of a PUSCH in one cell. Information included in DCI format 0_0 is CRC (cyclic redundancy check) scrambled by a C-RNTI (Cell Radio Network Temporary Identifier) or a CS-RNTI (Configured Scheduling RNTI) or a MCS-C-RNTI (Modulation Coding Scheme Cell RNTI) and transmitted.
DCI format 0_1 is used to indicate scheduling of one or more PUSCHs or configure grant (CG) downlink feedback information to a terminal in one cell. Information included in DCI format 0_1 is CRC scrambled by a C-RNTI or a CS-RNTI or a SP-CSI-RNTI (Semi-Persistent CSI RNTI) or a MCS-C-RNTI and transmitted.
DCI format 0_2 is used for scheduling of a PUSCH in one cell. Information included in DCI format 0_2 is CRC scrambled by a C-RNTI or a CS-RNTI or a SP-CSI-RNTI or a MCS-C-RNTI and transmitted.
Next, DCI formats 1_0, 1_1 and 1_2 may include resource information (e.g., frequency resource allocation, time resource allocation, VRB (virtual resource block)-PRB (physical resource block) mapping, etc.), information related to a transport block (TB) (e.g., MCS, NDI, RV, etc.), information related to a HARQ (e.g., a process number, DAI, PDSCH-HARQ feedback timing, etc.), information related to multiple antennas (e.g., an antenna port, a TCI (transmission configuration indicator), a SRS (sounding reference signal) request, etc.), information related to a PUCCH (e.g., PUCCH power control, a PUCCH resource indicator, etc.) related to scheduling of a PDSCH and control information included in each DCI format may be pre-defined.
DCI format 1_0 is used for scheduling of a PDSCH in one DL cell. Information included in DCI format 1_0 is CRC scrambled by a C-RNTI or a CS-RNTI or a MCS-C-RNTI and transmitted.
DCI format 1_1 is used for scheduling of a PDSCH in one cell. Information included in DCI format 1_1 is CRC scrambled by a C-RNTI or a CS-RNTI or a MCS-C-RNTI and transmitted.
DCI format 1_2 is used for scheduling of a PDSCH in one cell. Information included in DCI format 1_2 is CRC scrambled by a C-RNTI or a CS-RNTI or a MCS-C-RNTI and transmitted.
In an NR (New Radio) system, a CSI-RS (channel state information-reference signal) is used for time and/or frequency tracking, CSI computation, L1 (layer 1)-RSRP (reference signal received power) computation and mobility. Here, CSI computation is related to CSI acquisition and L1-RSRP computation is related to beam management (BM).
CSI (channel state information) collectively refers to information which may represent quality of a radio channel (or also referred to as a link) formed between a terminal and an antenna port.
To perform one of the usages of a CSI-RS, a terminal (e.g., user equipment, UE) receives configuration information related to CSI from a base station (e.g., general Node B, gNB) through RRC (radio resource control) signaling.
The configuration information related to CSI may include at least one of information related to a CSI-IM (interference management) resource, information related to CSI measurement configuration, information related to CSI resource configuration, information related to a CSI-RS resource or information related to CSI report configuration.
i) Information related to a CSI-IM resource may include CSI-IM resource information, CSI-IM resource set information, etc. A CSI-IM resource set is identified by a CSI-IM resource set ID (identifier) and one resource set includes at least one CSI-IM resource. Each CSI-IM resource is identified by a CSI-IM resource ID.
ii) Information related to CSI resource configuration may be expressed as CSI-ResourceConfig IE. Information related to a CSI resource configuration defines a group which includes at least one of an NZP (non zero power) CSI-RS resource set, a CSI-IM resource set or a CSI-SSB resource set. In other words, the information related to a CSI resource configuration may include a CSI-RS resource set list and the CSI-RS resource set list may include at least one of a NZP CSI-RS resource set list, a CSI-IM resource set list or a CSI-SSB resource set list. A CSI-RS resource set is identified by a CSI-RS resource set ID and one resource set includes at least one CSI-RS resource. Each CSI-RS resource is identified by a CSI-RS resource ID.
Parameters representing a usage of a CSI-RS (e.g., a ‘repetition’ parameter related to BM, a ‘trs-Info’ parameter related to tracking) may be configured per NZP CSI-RS resource set.
iii) Information related to a CSI report configuration includes a report configuration type (reportConfigType) parameter representing a time domain behavior and a report quantity (reportQuantity) parameter representing CSI-related quantity for a report. The time domain behavior may be periodic, aperiodic or semi-persistent.
A terminal measures CSI based on the configuration information related to CSI.
The CSI measurement may include (1) a process in which a terminal receives a CSI-RS and (2) a process in which CSI is computed through a received CSI-RS and detailed description thereon is described after.
For a CSI-RS, RE (resource element) mapping of a CSI-RS resource in a time and frequency domain is configured by higher layer parameter CSI-RS-ResourceMapping.
A terminal reports the measured CSI to a base station.
In this case, when quantity of CSI-ReportConfig is configured as ‘none (or No report)’, the terminal may omit the report. But, although the quantity is configured as ‘none (or No report)’, the terminal may perform a report to a base station. When the quantity is configured as ‘none’, an aperiodic TRS is triggered or repetition is configured. In this case, only when repetition is configured as ‘ON’, a report of the terminal may be omitted.
An NR system supports more flexible and dynamic CSI measurement and reporting. Here, the CSI measurement may include a procedure of receiving a CSI-RS and acquiring CSI by computing a received CSI-RS.
As a time domain behavior of CSI measurement and reporting, aperiodic/semi-persistent/periodic CM (channel measurement) and IM (interference measurement) are supported. 4-port NZP CSI-RS RE pattern is used for CSI-IM configuration.
CSI-IM based IMR of NR has a design similar to CSI-IM of LTE and is configured independently from ZP CSI-RS resources for PDSCH rate matching. In addition, each port emulates an interference layer having (a desirable channel and) a precoded NZP CSI-RS in NZP CSI-RS-based IMR. As it is about intra-cell interference measurement for a multi-user case, MU interference is mainly targeted.
A base station transmits a precoded NZP CSI-RS to a terminal in each port of configured NZP CSI-RS based IMR.
A terminal assumes a channel/interference layer and measures interference for each port in a resource set.
When there is no PMI and RI feedback for a channel, a plurality of resources are configured in a set and a base station or a network indicates a subset of NZP CSI-RS resources through DCI for channel/interference measurement.
A resource setting and a resource setting configuration are described in more detail.
Each CSI resource setting ‘CSI-ResourceConfig’ includes a configuration for a S≥1 CSI resource set (given by a higher layer parameter csi-RS-ResourceSetList). A CSI resource setting corresponds to CSI-RS-resourcesetlist. Here, S represents the number of configured CSI-RS resource sets. Here, a configuration for a S≥1 CSI resource set includes each CSI resource set including CSI-RS resources (configured with a NZP CSI-RS or CSI-IM) and a SS/PBCH block (SSB) resource used for L1-RSRP computation.
Each CSI resource setting is positioned at a DL BWP (bandwidth part) identified by a higher layer parameter bwp-id. In addition, all CSI resource settings linked to a CSI reporting setting have the same DL BWP.
A time domain behavior of a CSI-RS resource in a CSI resource setting included in a CSI-ResourceConfig IE may be indicated by a higher layer parameter resourceType and may be configured to be aperiodic, periodic or semi-persistent. For a periodic and semi-persistent CSI resource setting, the number(S) of configured CSI-RS resource sets is limited to ‘1’. For a periodic and semi-persistent CSI resource setting, configured periodicity and a slot offset are given by a numerology of an associated DL BWP as given by bwp-id.
When UE is configured with a plurality of CSI-ResourceConfigs including the same NZP CSI-RS resource ID, the same time domain behavior is configured for CSI-ResourceConfig.
When UE is configured with a plurality of CSI-ResourceConfigs including the same CSI-IM resource ID, the same time domain behavior is configured for CSI-ResourceConfig.
One or more CSI resource settings for channel measurement (CM) and interference measurement (IM) are configured through higher layer signaling as follows.
In other words, a CMR (channel measurement resource) may be a NZP CSI-RS for CSI acquisition and an IMR (Interference measurement resource) may be a NZP CSI-RS for CSI-IM and IM.
In this case, CSI-IM (or a ZP CSI-RS for IM) is mainly used for inter-cell interference measurement.
In addition, an NZP CSI-RS for IM is mainly used for intra-cell interference measurement from multi-users.
UE may assume that CSI-RS resource(s) for channel measurement and CSI-IM/NZP CSI-RS resource(s) for interference measurement configured for one CSI reporting are ‘QCL-TypeD’ per resource.
As described, a resource setting may mean a resource set list.
For aperiodic CSI, each trigger state configured by using a higher layer parameter CSI-AperiodicTriggerState is associated with one or a plurality of CSI-ReportConfigs that each CSI-ReportConfig is linked to a periodic, semi-persistent or aperiodic resource setting.
One reporting setting may be connected to up to 3 resource settings.
When one resource setting is configured, a resource setting (given by a higher layer parameter resourcesForChannelMeasurement) is about channel measurement for L1-RSRP computation.
When two resource settings are configured, a first resource setting (given by a higher layer parameter resourcesForChannelMeasurement) is for channel measurement and a second resource setting (given by csi-IM-ResourcesForInterference or nzp-CSI-RS-ResourcesForInterference) is for interference measurement performed in CSI-IM or a NZP CSI-RS.
When three resource settings are configured, a first resource setting (given by resourcesForChannelMeasurement) is for channel measurement, a second resource setting (given by csi-IM-ResourcesForInterference) is for CSI-IM based interference measurement and a third resource setting (given by nzp-CSI-RS-ResourcesForInterference) is for NZP CSI-RS based interference measurement.
For semi-persistent or periodic CSI, each CSI-ReportConfig is linked to a periodic or semi-persistent resource setting.
When one resource setting (given by resourcesForChannelMeasurement) is configured, the resource setting is about channel measurement for L1-RSRP computation.
When two resource settings are configured, a first resource setting (given by resourcesForChannelMeasurement) is for channel measurement and a second resourece setting (given by a higher layer parameter csi-IM-ResourcesForInterference) is used for interference measurement performed in CSI-IM.
When interference measurement is performed in CSI-IM, each CSI-RS resource for channel measurement is associated with a CSI-IM resource per resource in an order of CSI-RS resources and CSI-IM resources in a corresponding resource set. The number of CSI-RS resources for channel measurement is the same as the number of CSI-IM resources.
In addition, when interference measurement is performed in an NZP CSI-RS, UE does not expect to be configured with one or more NZP CSI-RS resources in an associated resource set in a resource setting for channel measurement.
A terminal configured with a higher layer parameter nzp-CSI-RS-ResourcesForInterference does not expect that 18 or more NZP CSI-RS ports will be configured in a NZP CSI-RS resource set.
For CSI measurement, a terminal assumes the followings.
Each NZP CSI-RS port configured for interference measurement corresponds to an interference transmission layer.
All interference transmission layers of an NZP CSI-RS port for interference measurement consider EPRE (energy per resource element) ratio.
A different interference signal in RE(s) of an NZP CSI-RS resource for channel measurement, an NZP CSI-RS resource for interference measurement or a CSI-IM resource for interference measurement
For a CSI report, a time and frequency resource which may be used by UE are controlled by a base station.
CSI (channel state information) may include at least one of a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), a SS/PBCH block resource indicator (SSBRI), a layer indicator (LI), a rank indicator (RI) or L1-RSRP.
For CQI, PMI, CRI, SSBRI, LI, RI, L1-RSRP, a terminal is configured by a higher layer with N≥1 CSI-ReportConfig reporting setting, M≥1 CSI-ResourceConfig resource setting and a list of one or two trigger states (provided by aperiodicTriggerStateList and semiPersistentOnPUSCH-TriggerStateList). Each trigger state in the aperiodicTriggerStateList includes a associated CSI-ReportConfigs list which indicates a channel and optional resource set IDs for interference. In semiPersistentOnPUSCH-TriggerStateList, one associated CSI-ReportConfig is included in each trigger state.
In addition, a time domain behavior of CSI reporting supports periodic, semi-persistent, aperiodic.
i) Periodic CSI reporting is performed in a short PUCCH, a long PUCCH. Periodicity and a slot offset of periodic CSI reporting may be configured by RRC and refers to a CSI-ReportConfig IE.
ii) SP (semi-periodic) CSI reporting is performed in a short PUCCH, a long PUCCH, or a PUSCH.
For SP CSI in a short/long PUCCH, periodicity and a slot offset are configured by RRC and a CSI report is activated/deactivated by separate MAC CE/DCI.
For SP CSI in a PUSCH, periodicity of SP CSI reporting is configured by RRC, but a slot offset is not configured by RRC and SP CSI reporting is activated/deactivated by DCI (format 0_1). For SP CSI reporting in a PUSCH, a separated RNTI (SP-CSI C-RNTI) is used.
An initial CSI report timing follows a PUSCH time domain allocation value indicated by DCI and a subsequent CSI report timing follows a periodicity configured by RRC.
DCI format 0_1 may include a CSI request field and activate/deactivate a specific configured SP-CSI trigger state. SP CSI reporting has activation/deactivation equal or similar to a mechanism having data transmission in a SPS PUSCH.
iii) Aperiodic CSI reporting is performed in a PUSCH and is triggered by DCI. In this case, information related to trigger of aperiodic CSI reporting may be delivered/indicated/configured through MAC-CE.
For AP CSI having an AP CSI-RS, AP CSI-RS timing is configured by RRC and timing for AP CSI reporting is dynamically controlled by DCI.
In NR, a method of dividing and reporting CSI in a plurality of reporting instances applied to a PUCCH based CSI report in LTE (e.g., transmitted in an order of RI, WB PMI/CQI, SB PMI/CQI) is not applied. Instead, in NR, there is a limit that a specific CSI report is not configured in a short/long PUCCH and a CSI omission rule is defined. In addition, regarding AP CSI reporting timing, a PUSCH symbol/slot location is dynamically indicated by DCI. In addition, candidate slot offsets are configured by RRC. For CSI reporting, a slot offset (Y) is configured per reporting setting. For UL-SCH, a slot offset K2 is separately configured.
2 CSI latency classes (low latency class, high latency class) are defined with regard to CSI computation complexity. Low latency CSI is WB CSI which includes up to 4 ports Type-I codebooks or up to 4 ports non-PMI feedback CSI. High latency CSI refers to CSI other than low latency CSI. For a normal terminal, (Z, Z′) is defined in a unit of OFDM symbols. Here, Z represents the minimum CSI processing time until a CSI report is performed after receiving aperiodic CSI triggering DCI. In addition, Z′ refers to the minimum CSI processing time until a CSI report is performed after receiving a CSI-RS for a channel/interference.
Additionally, a terminal reports the number of CSI which may be calculated at the same time.
An antenna port is defined so that a channel where a symbol in an antenna port is transmitted can be inferred from a channel where other symbol in the same antenna port is transmitted. When a property of a channel where a symbol in one antenna port is carried may be inferred from a channel where a symbol in other antenna port is carried, it may be said that 2 antenna ports are in a QC/QCL (quasi co-located or quasi co-location) relationship.
Here, the channel property includes at least one of delay spread, doppler spread, frequency/doppler shift, average received power, received timing/average delay, or a spatial RX parameter. Here, a spatial Rx parameter means a spatial (Rx) channel property parameter such as an angle of arrival.
A terminal may be configured at list of up to M TCI-State configurations in a higher layer parameter PDSCH-Config to decode a PDSCH according to a detected PDCCH having intended DCI for a corresponding terminal and a given serving cell. The M depends on UE capability.
Each TCI-State includes a parameter for configuring a quasi co-location relationship between ports of one or two DL reference signals and a DM-RS (demodulation reference signal) of a PDSCH.
A quasi co-location relationship is configured by a higher layer parameter qcl-Type1 for a first DL RS and qcl-Type2 for a second DL RS (if configured). For two DL RSs, a QCL type is not the same regardless of whether a reference is a same DL RS or a different DL RS.
A QCL type corresponding to each DL RS is given by a higher layer parameter qcl-Type of QCL-Info and may take one of the following values.
For example, when a target antenna port is a specific NZP CSI-RS, it may be indicated/configured that a corresponding NZP CSI-RS antenna port is quasi-colocated with a specific TRS with regard to QCL-Type A and is quasi-colocated with a specific SSB with regard to QCL-Type D. A terminal received such indication/configuration may receive a corresponding NZP CSI-RS by using a doppler, delay value measured in a QCL-TypeA TRS and apply a Rx beam used for receiving QCL-TypeD SSB to reception of a corresponding NZP CSI-RS.
UE may receive an activation command by MAC CE signaling used to map up to 8 TCI states to a codepoint of a DCI field ‘Transmission Configuration Indication’.
A coordinated multi point (CoMP) scheme refers to a scheme in which a plurality of base stations effectively control interference by exchanging (e.g., using an X2 interface) or utilizing channel information (e.g., RI/CQI/PMI/LI (layer indicator), etc.) fed back by a terminal and cooperatively transmitting to a terminal. According to a scheme used, a COMP may be classified into joint transmission (JT), coordinated Scheduling (CS), coordinated Beamforming (CB), dynamic Point Selection (DPS), dynamic Point Blocking (DPB), etc.
M-TRP transmission schemes that M TRPs transmit data to one terminal may be largely classified into i) eMBB M-TRP transmission, a scheme for improving a transfer rate, and ii) URLLC M-TRP transmission, a scheme for increasing a reception success rate and reducing latency.
In addition, with regard to DCI transmission, M-TRP transmission schemes may be classified into i) M-TRP transmission based on M-DCI (multiple DCI) that each TRP transmits different DCIs and ii) M-TRP transmission based on S-DCI (single DCI) that one TRP transmits DCI. For example, for S-DCI based M-TRP transmission, all scheduling information on data transmitted by M TRPs should be delivered to a terminal through one DCI, it may be used in an environment of an ideal BackHaul (ideal BH) where dynamic cooperation between two TRPs is possible.
For TDM based URLLC M-TRP transmission, scheme 3/4 is under discussion for standardization. Specifically, scheme 4 means a scheme in which one TRP transmits a transport block (TB) in one slot and it has an effect to improve a probability of data reception through the same TB received from multiple TRPs in multiple slots. Meanwhile, scheme 3 means a scheme in which one TRP transmits a TB through consecutive number of OFDM symbols (i.e., a symbol group) and TRPs may be configured to transmit the same TB through a different symbol group in one slot.
In addition, UE may recognize PUSCH (or PUCCH) scheduled by DCI received in different control resource sets (CORESETs) (or CORESETs belonging to different CORESET groups) as PUSCH (or PUCCH) transmitted to different TRPs or may recognize PDSCH (or PDCCH) from different TRPs. In addition, the below-described method for UL transmission (e.g., PUSCH/PUCCH) transmitted to different TRPs may be applied equivalently to UL transmission (e.g., PUSCH/PUCCH) transmitted to different panels belonging to the same TRP.
In addition, MTRP-URLLC may mean that a M TRPs transmit the same transport block (TB) by using different layer/time/frequency. A UE configured with a MTRP-URLLC transmission scheme receives an indication on multiple TCI state(s) through DCI and may assume that data received by using a QCL RS of each TCI state are the same TB. On the other hand, MTRP-eMBB may mean that M TRPs transmit different TBs by using different layer/time/frequency. A UE configured with a MTRP-eMBB transmission scheme receives an indication on multiple TCI state(s) through DCI and may assume that data received by using a QCL RS of each TCI state are different TBs. In this regard, as UE separately classifies and uses a RNTI configured for MTRP-URLLC and a RNTI configured for MTRP-eMBB, it may decide/determine whether the corresponding M-TRP transmission is URLLC transmission or eMBB transmission. In other words, when CRC masking of DCI received by UE is performed by using a RNTI configured for MTRP-URLLC, it may correspond to URLLC transmission, and when CRC masking of DCI is performed by using a RNTI configured for MTRP-eMBB, it may correspond to eMBB transmission.
Hereinafter, a CORESET group ID described/mentioned in the present disclosure may mean an index/identification information (e.g., an ID, etc.) for distinguishing a CORESET for each TRP/panel. In addition, a CORESET group may be a group/union of CORESET distinguished by an index/identification information (e.g., an ID)/the CORESET group ID, etc. for distinguishing a CORESET for each TRP/panel. In an example, a CORESET group ID may be specific index information defined in a CORESET configuration. In this case, a CORESET group may be configured/indicated/defined by an index defined in a CORESET configuration for each CORESET. Additionally/alternatively, a CORESET group ID may mean an index/identification information/an indicator, etc. for distinguishment/identification between CORESETs configured/associated with each TRP/panel. Hereinafter, a CORESET group ID described/mentioned in the present disclosure may be expressed by being substituted with a specific index/specific identification information/a specific indicator for distinguishment/identification between CORESETs configured/associated with each TRP/panel. The CORESET group ID, i.e., a specific index/specific identification information/a specific indicator for distinguishment/identification between CORESETs configured/associated with each TRP/panel may be configured/indicated to a terminal through higher layer signaling (e.g., RRC signaling)/L2 signaling (e.g., MAC-CE)/L1 signaling (e.g., DCI), etc. In an example, it may be configured/indicated so that PDCCH detection will be performed per each TRP/panel in a unit of a corresponding CORESET group (i.e., per TRP/panel belonging to the same CORESET group). Additionally/alternatively, it may be configured/indicated so that uplink control information (e.g., CSI, HARQ-A/N (ACK/NACK), SR (scheduling request)) and/or uplink physical channel resources (e.g., PUCCH/PRACH/SRS resources) are separated and managed/controlled per each TRP/panel in a unit of a corresponding CORESET group (i.e., per TRP/panel belonging to the same CORESET group). Additionally/alternatively, HARQ A/N (process/retransmission) for PDSCH/PUSCH, etc. scheduled per each TRP/panel may be managed per corresponding CORESET group (i.e., per TRP/panel belonging to the same CORESET group).
For example, a higher layer parameter, ControlResourceSet information element (IE), is used to configure a time/frequency control resource set (CORESET). In an example, the control resource set (CORESET) may be related to detection and reception of downlink control information. The ControlResourceSet IE may include a CORESET-related ID (e.g., controlResourceSetID)/an index of a CORESET pool for a CORESET (e.g., CORESETPoolIndex)/a time/frequency resource configuration of a CORESET/TCI information related to a CORESET, etc. In an example, an index of a CORESET pool (e.g., CORESETPoolIndex) may be configured as 0 or 1. In the description, a CORESET group may correspond to a CORESET pool and a CORESET group ID may correspond to a CORESET pool index (e.g., CORESETPoolIndex).
NCJT (Non-coherent joint transmission) is a scheme in which a plurality of transmission points (TP) transmit data to one terminal by using the same time frequency resource, TPs transmit data by using a different DMRS (Demodulation Multiplexing Reference Signal) between TPs through a different layer (i.e., through a different DMRS port).
A TP delivers data scheduling information through DCI to a terminal receiving NCJT. Here, a scheme in which each TP participating in NCJT delivers scheduling information on data transmitted by itself through DCI is referred to as ‘multi DCI based NCJT’. As each of N TPs participating in NCJT transmission transmits DL grant DCI and a PDSCH to UE, UE receives N DCI and N PDSCHs from N TPs. Meanwhile, a scheme in which one representative TP delivers scheduling information on data transmitted by itself and data transmitted by a different TP (i.e., a TP participating in NCJT) through one DCI is referred to as ‘single DCI based NCJT’. Here, N TPs transmit one PDSCH, but each TP transmits only some layers of multiple layers included in one PDSCH. For example, when 4-layer data is transmitted, TP 1 may transmit 2 layers and TP 2 may transmit 2 remaining layers to UE.
Hereinafter, partially overlapped NCJT will be described.
In addition, NCJT may be classified into fully overlapped NCJT that time frequency resources transmitted by each TP are fully overlapped and partially overlapped NCJT that only some time frequency resources are overlapped. In other words, for partially overlapped NCJT, data of both of TP 1 and TP 2 are transmitted in some time frequency resources and data of only one TP of TP 1 or TP 2 is transmitted in remaining time frequency resources.
Hereinafter, a method for improving reliability in Multi-TRP will be described.
As a transmission and reception method for improving reliability using transmission in a plurality of TRPs, the following two methods may be considered.
In reference to
In reference to
According to methods illustrated in
In addition, the above-described contents related to multiple TRPs are described based on an SDM (spatial division multiplexing) method using different layers, but it may be naturally extended and applied to a FDM (frequency division multiplexing) method based on a different frequency domain resource (e.g., RB/PRB (set), etc.) and/or a TDM (time division multiplexing) method based on a different time domain resource (e.g., a slot, a symbol, a sub-symbol, etc.). CSI computation time
When a CSI request field on DCI triggers a CSI report(s) on a PUSCH, a UE shall provide a valid CSI report for the n-th triggered report,
If the PUSCH indicated by the DCI is overlapping with another PUCCH of PUSCH, then the CSI report(s) are multiplexed following the procedure define in the standard when applicable, otherwise the CSI report(s) are transmitted on the PUSCH indicated by the DCI.
When the CSI request field on a DCI triggers a CSI report(s) on PUSCH, if the first uplink symbol to carry the corresponding CSI report(s) including the effect of the timing advance, starts earlier than at symbol Zref, the UE may ignore the scheduling DCI if no HARQ-ACK or transport block is multiplexed on the PUSCH.
When the CSI request field on a DCI triggers a CSI report(s) on PUSCH, if the first uplink symbol to carry the n-th CSI report including the effect of the timing advance, starts earlier than at symbol Z′ref (n), the UE may ignore the scheduling DCI if the number of triggered reports is one and no HARQ-ACK or transport block is multiplexed on the PUSCH. Otherwise, the UE is not required to update the CSI for the n-th triggered CSI report.
Z, Z′ and μ are defined as:
Z=maxm=0, . . . ,M−1 (Z (m)) and Z′=maxm=0, . . . ,M−1 (Z′(m)), where M is the number of updated CSI report(s), (Z (m),Z′(m)) corresponds to the m-th updated CSI report and is defined as:
Table 6 illustrates CSI computation delay requirement 1.
Table 7 illustrates CSI computation delay requirement 2.
In this disclosure, ‘/’ may mean including (and) all of the content separated by / or including (or) only part of the separated content.
Non-coherent joint transmission (NCJT) channel measurement resource (CMR) refers to an NZP-CSI-RS resource for paired channel measurement for calculation/derivation/reporting of NCJT CSI (i.e. multi-TRP (M-TRP) CSI). In other words, it means an NZP-CSI-RS resource for paired channel measurement for calculation/derivation/reporting of NCJT CSI (i.e. M-TRP (multi-TRP) CSI) based on the NCJT measurement hypothesis.
In addition, in the present disclosure, a single TRP (STRP) CMR refers to an NZP-CSI-RS resource for channel measurement for calculation/derivation/reporting of STRP CSI. In other words, STRP CMR refers to an NZP-CSI-RS resource for channel measurement for calculation/derivation/reporting of STRP CSI based on the STRP measurement hypothesis.
This will be described with reference to the drawings below.
N (N is a natural number) CMR pair(s) and two CMR groups may be configured for each NZP-CSI-RS resource set for channel measurement. That is, an NZP-CSI-RS resource set for one channel measurement may include two resource groups for NZP-CSI-RS resources, and NZP-CSI-RS resources included in an NZP-CSI-RS resource set may be grouped into two groups (i.e., group 1 and group 2 in
Additionally, two NZP-CSI-RS resources belonging to different resource groups may be paired (pair 1, pair 2 in
In addition, among NZP-CSI-RS resources belonging to each group, resources for which a pair is not configured may be referred to as an STRP CMR in the present disclosure. In
Each resource pair configured in an NZP-CSI-RS resource set may correspond to a CRI for one MTRP, and each NZP-CSI-RS resource that does not belong to a resource pair may correspond to a CRI for one STRP. Therefore, when reporting CSI for a channel with MTRP (hereinafter referred to as MTRP CSI), a UE may report any one resource pair (i.e., CRI) among the configured resource pairs to a base station. Additionally, when reporting CSI for a channel with STRP (hereinafter referred to as STRP CSI), a UE may report any resource (i.e., CRI) that does not belong to the resource pair to a base station.
Hereinafter, before describing the methods proposed in this disclosure, M-TRP-related operations will be described.
In the NR Rel-17 standard, enhancements to the SFN transmission method in which M-TRP transmits the same data together in the same time/frequency resource region with the same layer and the same DMRS port are in progress. For example, in layer 1 M-TRP SFN transmission, TRP 1 and TRP 2 transmit the same data to a UE using the same DMRS port and the same time/frequency resources. Here, as the DL QCL beam information for a DMRS is configured for each TRP, both QCL beam information (i.e. QCL reference RS configured in TCI state) for TRP 1 and QCL beam information for TRP 2 can be configured for the DMRS port. Since the same data transmitted by two TRPs is received through one DMRS port, the channel estimated through the DMRS port corresponds to a composite channel combining a DL channel of TRP 1 and a DL channel of TRP 2. Here, the composite channel appears randomly as a constructive sum or a destructive sum because the channel phases of each TRP are not aligned with each other. From this perspective, SFN transmission can be said to be a type of M-TRP NCJT, and since MTRP transmits a common layer, it is referred to as common layer NCJT.
M-TRP NCJT was introduced in NR Rel-16. Two TRPs transmit different data using different layers/different DMRS ports. For example, DMRS ports belonging to different CDM groups are grouped, and DMRS port(s) belonging to the first CDM group are received using the first QCL beam information (i.e., the configured first TCI state), and DMRS port(s) belonging to the second CDM group are received using the second QCL beam information (i.e., the configured second TCI state). Since the layers/DMRS ports transmitted by the two TRPs are separated from each other, and data is not transmitted/received through a composite channel, there is no need to align the channel phases of the two TRPs. Therefore, this is referred to as non-coherent JT, and since independent layers are transmitted for each TRP, it is referred to as independent layer NCJT.
Similar to M-TRP SFN, in M-TRP CJT, the same data in the same time/frequency resource area with the same layer and the same DMRS port is transmitted. However, unlike M-TRP SFN, in M-TRP CJT, the channel phases of each TRP are aligned with each other, so ideally, the two channels are constructively summed to create a composite channel, as a result, a higher signal-to-noise ratio (SNR) gain is obtained through beamforming than SFN. To ensure that the channel phases of each TRP are aligned with each other, a UE can feed back the phase difference between the two TRP channels by adding it to the existing CSI. Additionally, when data is transmitted in multi-layers, a case in which CJT transmission is performed in some layers but only a single TRP is transmitted in some layers may be supported. For example, when transmitting a rank 2 PDSCH, TRPs 1 and 2 perform CJT in the first layer and both TRPs transmit the same data, but only TRP 1 can transmit data in the second layer.
Regarding the C-JT (Coherent joint transmission) scheme, which is expected to be discussed after NR Rel-18, if the C-JT scheme is introduced, it may be necessary to introduce a new CSI computation time other than the CSI computation time defined in the current standard.
Accordingly, this disclosure proposes a method for defining a CSI computation time of the CJT scheme.
The following method can be defined as an example of a method of configuring a resource for channel measurement (CM) for C-JT CSI calculation.
The following method can be defined as an example of a C-JT transmission method.
In the present disclosure, for convenience of explanation, it is assumed that two TRPs (e.g., TRP1/TRP2) are operating. However, this is for convenience of explanation, and this assumption does not limit the technical scope of the proposed method of the present disclosure.
The description of the TRP in the present disclosure is for convenience of explanation, and the TRP can also be interpreted as a term such as panel/beam.
In the present disclosure, L1 (layer 1) signaling may refer to DCI-based dynamic signaling between a base station and a UE, and L2 (layer 2) signaling may refer to higher layer signaling based on an RRC/MAC control element (CE: control element) between a base station and a UE.
Hereinafter, the present disclosure proposes a method for defining a CSI computation time for CJT.
Embodiment 1: Multiple QCL reference RSs may be configured in a single CMR.
For example, grouping CSI-RS ports of a single CMR into a CSI-RS port group, and a different QCL reference RS (i.e., a QCL reference RS configured in a TCI state) may be configured/mapped for each CSI-RS port group. And/or, a codebook of an enhanced PMI for C-JT may be configured/mapped for each CSI-RS port group.
As above, when multiple QCL reference RSs are configured in a single CMR (e.g., different QCL reference RS configurations and/or individual PMI codebook configurations for each CSI-RS port group of a single CMR), a UE may assume that a CSI report configuration including (or linked/associated) the corresponding CMR configuration corresponds to C-JT CSI.
In other words, a base station may not explicitly configure/indicate a UE to report C-JT CSI, and when a CMR for C-JT is configured separately and CSI is reported for the CMR for the C-JT, the CSI report may be implicitly configured/indicated to a UE as a C-JT CSI report.
When calculating CSI for the C-JT CSI reporting, a UE may be configured/defined to apply Z, Z′ values greater than or equal to Z, Z′ (e.g., (Z1, Z1′), (Z2, Z2′), (Z3, Z3′)), which is the CSI computation time defined in the current standard described above.
For example, when reporting C-JT CSI, as CSI processing time to calculate CSI computation time, Z, Z′ values greater than the Z and Z′ (maximum value among them) defined in Tables 6 and 7 may be defined/determined. Alternatively, only one of Z and Z′ may be defined/determined to be larger than Z and Z′ (maximum value among them) defined in Tables 6 and 7.
For a normal UE, (Z, Z′) is defined in units of OFDM symbols. Here, Z represents the minimum CSI processing time from receiving an aperiodic CSI (triggering DCI) to performing a CSI report. Additionally, Z′ represents the minimum CSI processing time from receiving a CSI-RS for channel/interference to performing a CSI report.
C-JT CSI reporting may mean CSI reporting for a concatenated channel from M-TRP. For example, assuming that a CMR configured for C-JT is a single CMR, a UE can calculate a RI/PMI/CQI. That is, a UE can calculate a PMI and an RI using a codebook for all CSI-RS ports and can calculate an achievable CQI when the PMI/RI is applied to data transmission.
Alternatively, C-JT CSI may mean reporting multiple PMIs/RIs/CQIs for each channel from the M-TRP and reporting cophase between two PMIs. That is, a UE can calculate a PMI and an RI using a codebook for the corresponding CSI-RS port for each CSI-RS port group, and can calculate an achievable CQI when the PMI/RI is applied to data transmission. In addition, the UE can additionally calculate a cophase between the two PMIs.
Additionally, when calculating CSI for C-JT CSI reporting, it may be defined/configured to exclude a fast CSI feedback condition.
Here, the fast CSI feedback condition may mean the following condition:
In other words, when interpreting CSI under the above conditions, the C-JT CSI can be interpreted to exclude.
In order to calculate C-JT CSI, higher complexity and computational amount may be required compared to CSI calculation for a single TRP. Therefore, in this case, implementation complexity may increase in order to implement a UE to calculate C-JT CSI within the same CSI computation time as a single TRP CSI and it may have the disadvantage of reducing the efficiency of the UE, such as increasing battery consumption, and increasing the cost of implementation. On the other hand, when defining a CSI computation time for C-JT CSI calculation according to this proposed method, the CSI computation time can be relaxed to reduce the implementation complexity of a UE, thereby increasing the efficiency of the UE.
Embodiment 2: For C-JT CSI calculation, a CMR pair may be configured based on a plurality of CMRs.
For example, a CMR pair for C-JT CSI may be configured/defined separately from a CMR pair for NCJT (see
When calculating C-JR CSI based on a CMR pair, the fast CSI feedback condition can be relaxed.
The fast CSI feedback condition may mean the following condition.
Here, ‘relaxing’ the fast CSI feedback condition may mean that the content defined as a ‘single resource’ in the fast CSI feedback condition can be interpreted as being excluded from the condition. In other words, it can be defined so that the fast CSI feedback can be performed even when a CMR pair is configured based on two CMRs. For example, in the conditions above, ‘single resource’ can be replaced with ‘single resource or single resource pair’.
Additionally/or, when a CMR pair is configured to a UE based on a plurality of CMRs and a CMR within the CMR pair is configured not to be used for S-TRP CSI calculation (e.g. if sharedCMR is not configured), it can be defined to operate according to the condition proposed above (i.e., relaxed fast CSI feedback condition). In other words, if CMRs in the CMR pair are configured to be used for S-TRP CSI calculation, the proposed condition (i.e., relaxed fast CSI feedback condition) may not be applied.
In addition, in calculating CSI for C-JT CSI reporting based on a CMR pair, a UE can be configured/defined to apply Z, Z′ values greater than or equal to the CSI computation time Z, Z′ (e.g. (Z1, ZV′), (Z2, Z2′), (Z3, Z3′)) defined in the current standard described above.
For example, when a UE reports C-JT CSI, as a CSI processing time for calculating a CSI computation time, Z, Z′ values larger than Z, Z′ (maximum value among them) defined in Table 6 and Table 7 may be defined/determined. Alternatively, for a UE, it may be defined/determined that only one of Z and Z′ is larger than Z and Z′ (the maximum value among them) previously defined in Tables 6 and 7.
Previously, in Embodiment 1, if a CMR used to report CSI was a C-JR CMR, a UE could implicitly consider that corresponding CSI is C-JR CSI. However, as in Embodiment 2, the following method can be applied to a UE to recognize whether a CSI report for a CMR pair is C-JR CSI.
For example, a parameter for requesting the generation of a concatenated channel may be defined in CSI reporting configuration, etc. And/or, a value of a CQI quantity parameter to request reporting of a plurality of PMIs/RIs/CQIs and cophase information between two PMIs may be defined.
Here, as an example of the generation of a concatenated channel, a UE can assume that two n port CSI-RS and m port CSI-RS configured as one CMR pair are one (n+m) port CSI-RS and calculate RI/PMI/CQI assuming the corresponding (n+m) port CSIRS as one CMR. In other words, the PMI and RI can be calculated using a codebook for (n+m) port, and the achievable CQI can be calculated when the calculated PMI/RI is applied to data transmission.
In addition, a UE may calculates PMIs and RIs for two n port CSI-RS and m port CSI-RS configured as one CMR pair, respectively, using a codebook for the corresponding CSI-RS port, and when the PMIs/RIs are applied to data transmission, the achievable CQIs can be calculated respectively. In addition, a UE can additionally calculate the cophase between the two PMIs.
The fast CSI feedback defined in the current standard has the disadvantage that its use is limited because it is defined to be applicable only to specific cases. On the other hand, if the fast CSI feedback condition is relaxed according to this proposed method, it can have the advantage of improving the scheduling ability of a base station by enabling fast reporting of C-JT CSI.
Embodiment 3: In performing C-JT CSI calculation, compared to ZDLJT and Z′DLJT, which are CSI computation times when different layer JTs are configured/indicated, when common layer JT is configured/indicated, ZCLJT1, Z′CLJT1, which is the CSI computation time for common layer JP-based C-JR CSI 1, can be defined as ZDLJT, Z′DLJT or less (i.e., ZDLJT≥ZCLJT1, Z′DLJT≥Z′CLJT1). And/or, ZCLJT2, Z′CLJT2, the CSI computation time for common layer JT-based C-JT CSI 2, can be defined as more than ZDLJT, Z′DLJT (i.e., ZDLJT≤ZCLJT2, Z′DLJT≤Z′CLJT2).
In the above embodiment, ZDLJT and Z′DLJT can be interpreted as the CSI computation time introduced for Rel-17 NCJT CSI calculation. If CSI computation time is not separately introduced for Rel-17 NCJT CSI calculation, the CSI computation time defined in the current standard can be followed (see Table 6 and Table 7 above).
In the case of common layer JT, the CSI calculation complexity of a UE may vary depending on how the CSI calculation is performed. When applying the present proposed method, by defining an appropriate CSI computation time according to a CSI calculation method of common layer JT, it has the advantage of providing a CSI computation time that can respond to the implementation complexity of a UE and improving the efficiency of a UE.
Here, UE/Network may be an example and may be applied by being substituted with a variety of devices as described in
In the following description, a network may be one base station including a plurality of TRPs or may be one cell including a plurality of TRPs. In an example, ideal/non-ideal backhaul may be configured between TRP 1 and TRP 2 included in a network. In addition, the following description is described based on a plurality of TRPs, but it may be also equivalently extended and applied to transmission through a plurality of panels. In addition, in the present disclosure, an operation in which a terminal receives a signal from TRP1/TRP2 may be interpreted/explained (or may be an operation) as an operation in which a terminal receives a signal from a network (via/using TRP1/2), and an operation in which a terminal transmits a signal to TRP1/TRP2 may be interpreted/explained (or may be an operation) as an operation in which a terminal transmits a signal to a network (via/using TRP1/TRP2), and vice versa.
In addition, as described above, a “TRP” may be applied by being substituted with a panel, an antenna array, a cell (e.g., macro cell/small cell/pico cell, etc.), TP (transmission point), base station (base station, gNB, etc.), etc. As described above, a TRP may be classified according to information (e.g., index, identifier (ID)) on the CORESET group (or CORESET pool). As an example, when one terminal is configured to perform transmission/reception with a plurality of TRPs (or cells), this may mean that a plurality of CORESET groups (or CORESET pools) are configured for one terminal. The configuration of such a CORESET group (or CORESET pool) may be performed through higher layer signaling (e.g., RRC signaling, etc.). In addition, a base station may mean a generic term for an object that transmits and receives data with a terminal. For example, the base station may include one or more TPs (Transmission Points), one or more TRPs (Transmission and Reception Points), etc. In addition, a TP and/or a TRP may include a panel of a base station, a transmission and reception unit, etc.
Referring to
Referring to
The configuration information related to CSI may include information for configuring an operation based on the previously proposed method (e.g., any one of Embodiment 1, Embodiment 2, Embodiment 3, and detailed examples thereof, or a combination of one or more (detailed) examples).
The configuration information related to the CSI may include at least one of information related to CSI-IM (interference management) resource, information related to CSI measurement configuration, information related to CSI resource configuration, information related to CSI-RS resource or information related to CSI report configuration.
In particular, here, the configuration information related to the CSI may include CSI reporting-related configuration information (i.e., CSI reporting setting) (e.g., RRC IE ‘CSI-ReportConfig’) (hereinafter, first configuration information) and CSI resource-related configuration information (i.e., CSI resource setting) (e.g., RRC IE ‘CSI-ResourceConfig’) (hereinafter, second configuration information). Additionally, the second configuration information may be included in the first configuration information.
Here, as described above, a plurality of CSI-RS resources for CSI calculation/measurement may be configured to a UE according to the second configuration information, and all or part of a plurality of CSI-RS resources may be configured as one or more resource pairs (i.e., CMR pairs). Here, one or more resource pairs may be configured to be used to derive CSI based on a single pair.
Additionally, the second configuration information may be associated/related to specific first configuration information, and according to the reportQuantity in the first configuration information, CSI reporting (e.g., CRI, PMI, RI, CQI, LI, etc.) for a plurality of CSI-RS resources can be configured for a UE based on the associated/related second configuration information.
For example, it may be configured to report a concatenated channel for each of the one or more resource pairs based on the first configuration information. And/or, it can be configured to report two PMIs, two RIs, two CQIs and cophase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs according to the first configuration information.
A network transmits a reference signal (e.g., CSI-RS, etc.) in a plurality of CSI-RS resources to a UE based on configuration information related to CSI (e.g., second configuration information) (S902). That is, a UE receives a reference signal (e.g., CSI-RS, etc.) in a plurality of CSI-RS resources based on configuration information related to CSI (e.g., second configuration information) from a network.
Here, a reference signal may be transmitted from a first TRP to a UE on some CSI-RS resources among the plurality of CSI-RS resources, and the reference signal may be transmitted from a second TRP to the UE on the remaining CSI-RS resources.
A network transmits downlink control information (DCI) that triggers a UE to report CSI (S903). That is, a UE receives downlink control information (DCI) from a network that triggers it to report CSI.
Here, DCI may be transmitted through a downlink control channel (e.g., PDCCH, etc.) and may schedule a downlink data channel (e.g., PDSCH)/uplink data channel (e.g., PUSCH) in addition to triggering of CSI reporting.
When configuration information related to a plurality of CSI reports is configured for a UE, CSI report-related configuration of one of them may be indicated by DCI, and a UE may calculate CSI (e.g., CRI, RI, PMI, CQI, LI, etc.) using a reference signal (e.g., CSI-RS, etc.) received from the resource(s) configured by CSI resource-related configuration associated/related to the indicated CSI report-related configuration.
For example, when configured to report a concatenated channel for each of the one or more resource pairs by the first configuration information, for the CSI, at least one of i) a minimum time (Z) from reception of the DCI to transmission of the CSI and ii) a minimum time (Z′) from reception of the CSI-RS to transmission of the CSI may be determined to be a value greater than CSI without a concatenated channel.
As another example, based on being configured to report two PMIs, two RIs, two CQIs and co-phase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs by the first configuration information, for the CSI, at least one of the Z and the Z′ may be determined to be a value greater than CSI without the concatenated channel. In other words, a CSI calculation delay time for CSI reporting for a UE can be guaranteed according to the Z and/or Z′ values determined as above.
As another example, based on the CSI corresponding to up to 4 CSI-RS ports in a single resource pair without CRI reporting, Z, Z′ for CSI without a concatenated channel may be applicable to the CSI. As described above, if the following fast CSI feedback conditions are satisfied, (Z1,Z′1) in Table 6 (i.e., Z, Z′ for the CSI without the concatenated channel) can be used for the corresponding CSI.
Additionally, the above operation (i.e., when the fast CSI feedback condition is satisfied, Z and Z′ for CSI without a concatenated channel are applied) may be limited to be applied only when CSI is configured not to be calculated based on a single CSI-RS resource among CSI-RS resources included in the one or more resource pairs.
A UE transmits CSI to a network based on DCI and configuration information related to CSI (e.g., first configuration information) (S904). That is, a network receives CSI from a UE based on DCI and configuration information related to CSI.
Here, as described above, when the first configuration information is configured to report a concatenated channel for each of the one or more resource pairs, the CSI may include information on the calculated/measured concatenated channel for each of one or more CSI resource pairs. In addition, when it is configured to report two PMIs, two RIs, two CQIs, and cophase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs according to the first configuration information, the CSI may include two PMIs, two RIs, two CQIs, and cophase information between the two PMIs.
Referring to
The configuration information related to CSI may include information for configuring an operation based on the previously proposed method (e.g., any one of Embodiment 1, Embodiment 2, Embodiment 3, and detailed examples thereof, or a combination of one or more (detailed) examples).
The configuration information related to the CSI may include at least one of information related to CSI-IM (interference management) resource, information related to CSI measurement configuration, information related to CSI resource configuration, information related to CSI-RS resource or information related to CSI report configuration.
In particular, here, the configuration information related to the CSI may include CSI reporting-related configuration information (i.e., CSI reporting setting) (e.g., RRC IE ‘CSI-ReportConfig’) (hereinafter, first configuration information) and CSI resource-related configuration information (i.e., CSI resource setting) (e.g., RRC IE ‘CSI-ResourceConfig’) (hereinafter, second configuration information). Additionally, the second configuration information may be included in the first configuration information.
Here, as described above, a plurality of CSI-RS resources for CSI calculation/measurement may be configured to a UE according to the second configuration information, and all or part of a plurality of CSI-RS resources may be configured as one or more resource pairs (i.e., CMR pairs). Here, one or more resource pairs may be configured to be used to derive CSI based on a single pair.
Additionally, the second configuration information may be associated/related to specific first configuration information, and according to the reportQuantity in the first configuration information, CSI reporting (e.g., CRI, PMI, RI, CQI, LI, etc.) for a plurality of CSI-RS resources can be configured for a UE based on the associated/related second configuration information.
For example, it may be configured to report a concatenated channel for each of the one or more resource pairs based on the first configuration information. And/or, it can be configured to report two PMIs, two RIs, two CQIs and cophase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs according to the first configuration information.
A UE receives a reference signal (e.g., CSI-RS, etc.) in a plurality of CSI-RS resources based on configuration information related to CSI (e.g., second configuration information) from a base station (S1002).
Here, a reference signal may be transmitted from a first TRP to a UE on some CSI-RS resources among the plurality of CSI-RS resources, and the reference signal may be transmitted from a second TRP to the UE on the remaining CSI-RS resources. That is, when one base station is configured to include a first TRP and a second TRP, a UE can receive a CSI-RS in a plurality of CSI-RS resources from a base station. On the other hand, when one base station corresponds to a first TRP and another base station corresponds to a second TRP, a UE may receive a reference signal on some CSI-RS resources from a first base station (i.e., corresponding to a first TRP) and receive a reference signal on the remaining CSI-RS resources from a second base station (i.e., corresponding to a second TRP).
A UE receives downlink control information (DCI) from a base station that triggers it to report CSI (S1002).
Here, DCI may be transmitted through a downlink control channel (e.g., PDCCH, etc.) and may schedule a downlink data channel (e.g., PDSCH)/uplink data channel (e.g., PUSCH) in addition to triggering of CSI reporting.
When configuration information related to a plurality of CSI reports is configured for a UE, CSI report-related configuration of one of them may be indicated by DCI, and a UE may calculate CSI (e.g., CRI, RI, PMI, CQI, LI, etc.) using a reference signal (e.g., CSI-RS, etc.) received from the resource(s) configured by CSI resource-related configuration associated/related to the indicated CSI report-related configuration.
For example, when configured to report a concatenated channel for each of the one or more resource pairs by the first configuration information, for the CSI, at least one of i) a minimum time (Z) from reception of the DCI to transmission of the CSI and ii) a minimum time (Z′) from reception of the CSI-RS to transmission of the CSI may be determined to be a value greater than CSI without a concatenated channel.
As another example, based on being configured to report two PMIs, two RIs, two CQIs and co-phase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs by the first configuration information, for the CSI, at least one of the Z and the Z′ may be determined to be a value greater than CSI without the concatenated channel. In other words, a CSI calculation delay time for CSI reporting for a UE can be guaranteed according to the Z and/or Z′ values determined as above.
As another example, based on the CSI corresponding to up to 4 CSI-RS ports in a single resource pair without CRI reporting, Z, Z′ for CSI without a concatenated channel may be applicable to the CSI. As described above, if the following fast CSI feedback conditions are satisfied, (Z1,Z′1) in Table 6 (i.e., Z, Z′ for the CSI without the concatenated channel) can be used for the corresponding CSI.
Additionally, the above operation (i.e., when the fast CSI feedback condition is satisfied, Z and Z′ for CSI without a concatenated channel are applied) may be limited to be applied only when CSI is configured not to be calculated based on a single CSI-RS resource among CSI-RS resources included in the one or more resource pairs.
A UE transmits CSI to a network based on DCI and configuration information related to CSI (e.g., first configuration information) (S1003).
Here, as described above, when the first configuration information is configured to report a concatenated channel for each of the one or more resource pairs, the CSI may include information on the calculated/measured concatenated channel for each of one or more CSI resource pairs. In addition, when it is configured to report two PMIs, two RIs, two CQIs, and cophase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs according to the first configuration information, the CSI may include two PMIs, two RIs, two CQIs, and cophase information between the two PMIs.
Referring to
The configuration information related to CSI may include information for configuring an operation based on the previously proposed method (e.g., any one of Embodiment 1, Embodiment 2, Embodiment 3, and detailed examples thereof, or a combination of one or more (detailed) examples).
The configuration information related to the CSI may include at least one of information related to CSI-IM (interference management) resource, information related to CSI measurement configuration, information related to CSI resource configuration, information related to CSI-RS resource or information related to CSI report configuration.
In particular, here, the configuration information related to the CSI may include CSI reporting-related configuration information (i.e., CSI reporting setting) (e.g., RRC IE ‘CSI-ReportConfig’) (hereinafter, first configuration information) and CSI resource-related configuration information (i.e., CSI resource setting) (e.g., RRC IE ‘CSI-ResourceConfig’) (hereinafter, second configuration information). Additionally, the second configuration information may be included in the first configuration information.
Here, as described above, a plurality of CSI-RS resources for CSI calculation/measurement may be configured to a UE according to the second configuration information, and all or part of a plurality of CSI-RS resources may be configured as one or more resource pairs (i.e., CMR pairs). Here, one or more resource pairs may be configured to be used to derive CSI based on a single pair.
Additionally, the second configuration information may be associated/related to specific first configuration information, and according to the reportQuantity in the first configuration information, CSI reporting (e.g., CRI, PMI, RI, CQI, LI, etc.) for a plurality of CSI-RS resources can be configured for a UE based on the associated/related second configuration information.
For example, it may be configured to report a concatenated channel for each of the one or more resource pairs based on the first configuration information. And/or, it can be configured to report two PMIs, two RIs, two CQIs and cophase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs according to the first configuration information.
A base station transmits a reference signal (e.g., CSI-RS, etc.) to a UE in a plurality of CSI-RS resources based on configuration information related to CSI (e.g., second configuration information) (S1102).
Here, a reference signal may be transmitted from a first TRP to a UE on some CSI-RS resources among the plurality of CSI-RS resources, and the reference signal may be transmitted from a second TRP to the UE on the remaining CSI-RS resources. That is, when one base station is configured to include a first TRP and a second TRP, a base station can transmit a CSI-RS in a plurality of CSI-RS resources to a UE. On the other hand, when one base station corresponds to a first TRP and another base station corresponds to a second TRP, the base station (i.e., corresponding to a first TRP) may transmit a reference signal on some CSI-RS resources to a UE.
A base station transmits downlink control information (DCI) that triggers a UE to report CSI (S1102).
Here, DCI may be transmitted through a downlink control channel (e.g., PDCCH, etc.) and may schedule a downlink data channel (e.g., PDSCH)/uplink data channel (e.g., PUSCH) in addition to triggering of CSI reporting.
When configuration information related to a plurality of CSI reports is configured for a UE, CSI report-related configuration of one of them may be indicated by DCI, and a UE may calculate CSI (e.g., CRI, RI, PMI, CQI, LI, etc.) using a reference signal (e.g., CSI-RS, etc.) received from the resource(s) configured by CSI resource-related configuration associated/related to the indicated CSI report-related configuration.
For example, when configured to report a concatenated channel for each of the one or more resource pairs by the first configuration information, for the CSI, at least one of i) a minimum time (Z) from reception of the DCI to transmission of the CSI and ii) a minimum time (Z′) from reception of the CSI-RS to transmission of the CSI may be determined to be a value greater than CSI without a concatenated channel.
As another example, based on being configured to report two PMIs, two RIs, two CQIs and co-phase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs by the first configuration information, for the CSI, at least one of the Z and the Z′ may be determined to be a value greater than CSI without the concatenated channel. In other words, a CSI calculation delay time for CSI reporting for a UE can be guaranteed according to the Z and/or Z′ values determined as above.
As another example, based on the CSI corresponding to up to 4 CSI-RS ports in a single resource pair without CRI reporting, Z, Z′ for CSI without a concatenated channel may be applicable to the CSI. As described above, if the following fast CSI feedback conditions are satisfied, (Z1,Z′1) in Table 6 (i.e., Z, Z′ for the CSI without the concatenated channel) can be used for the corresponding CSI.
Additionally, the above operation (i.e., when the fast CSI feedback condition is satisfied, Z and Z′ for CSI without a concatenated channel are applied) may be limited to be applied only when CSI is configured not to be calculated based on a single CSI-RS resource among CSI-RS resources included in the one or more resource pairs.
A CSI calculation delay time for CSI reporting for a UE may be guaranteed according to the Z and/or Z′ values determined as above. A base station can determine whether a CSI report transmitted from a UE is valid based on the Z and/or Z′ values determined as above.
A base station receives CSI from a UE based on DCI and configuration information related to CSI (e.g., first configuration information) (S1103).
Here, as described above, when the first configuration information is configured to report a concatenated channel for each of the one or more resource pairs, the CSI may include information on the calculated/measured concatenated channel for each of one or more CSI resource pairs. In addition, when it is configured to report two PMIs, two RIs, two CQIs, and cophase information between the two PMIs for two CSI-RS resources included in each of the one or more resource pairs according to the first configuration information, the CSI may include two PMIs, two RIs, two CQIs, and cophase information between the two PMIs.
In reference to
A first wireless device 100 may include one or more processors 102 and one or more memories 104 and may additionally include one or more transceivers 106 and/or one or more antennas 108. A processor 102 may control a memory 104 and/or a transceiver 106 and may be configured to implement description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. For example, a processor 102 may transmit a wireless signal including first information/signal through a transceiver 106 after generating first information/signal by processing information in a memory 104. In addition, a processor 102 may receive a wireless signal including second information/signal through a transceiver 106 and then store information obtained by signal processing of second information/signal in a memory 104. A memory 104 may be connected to a processor 102 and may store a variety of information related to an operation of a processor 102. For example, a memory 104 may store a software code including commands for performing all or part of processes controlled by a processor 102 or for performing description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. Here, a processor 102 and a memory 104 may be part of a communication modem/circuit/chip designed to implement a wireless communication technology (e.g., LTE, NR). A transceiver 106 may be connected to a processor 102 and may transmit and/or receive a wireless signal through one or more antennas 108. A transceiver 106 may include a transmitter and/or a receiver. A transceiver 106 may be used together with a RF (Radio Frequency) unit. In the present disclosure, a wireless device may mean a communication modem/circuit/chip.
A second wireless device 200 may include one or more processors 202 and one or more memories 204 and may additionally include one or more transceivers 206 and/or one or more antennas 208. A processor 202 may control a memory 204 and/or a transceiver 206 and may be configured to implement description, functions, procedures, proposals, methods and/or operation flows charts disclosed in the present disclosure. For example, a processor 202 may generate third information/signal by processing information in a memory 204, and then transmit a wireless signal including third information/signal through a transceiver 206. In addition, a processor 202 may receive a wireless signal including fourth information/signal through a transceiver 206, and then store information obtained by signal processing of fourth information/signal in a memory 204. A memory 204 may be connected to a processor 202 and may store a variety of information related to an operation of a processor 202. For example, a memory 204 may store a software code including commands for performing all or part of processes controlled by a processor 202 or for performing description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. Here, a processor 202 and a memory 204 may be part of a communication modem/circuit/chip designed to implement a wireless communication technology (e.g., LTE, NR). A transceiver 206 may be connected to a processor 202 and may transmit and/or receive a wireless signal through one or more antennas 208. A transceiver 206 may include a transmitter and/or a receiver. A transceiver 206 may be used together with a RF unit. In the present disclosure, a wireless device may mean a communication modem/circuit/chip.
Hereinafter, a hardware element of a wireless device 100, 200 will be described in more detail. It is not limited thereto, but one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., a functional layer such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors 102, 202 may generate one or more PDUs (Protocol Data Unit) and/or one or more SDUs (Service Data Unit) according to description, functions, procedures, proposals, methods and/or operation flow charts included in the present disclosure. One or more processors 102, 202 may generate a message, control information, data or information according to description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure. One or more processors 102, 202 may generate a signal (e.g., a baseband signal) including a PDU, a SDU, a message, control information, data or information according to functions, procedures, proposals and/or methods disclosed in the present disclosure to provide it to one or more transceivers 106, 206. One or more processors 102, 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 and obtain a PDU, a SDU, a message, control information, data or information according to description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure.
One or more processors 102, 202 may be referred to as a controller, a micro controller, a micro processor or a micro computer. One or more processors 102, 202 may be implemented by a hardware, a firmware, a software, or their combination. In an example, one or more ASICs (Application Specific Integrated Circuit), one or more DSPs (Digital Signal Processor), one or more DSPDs (Digital Signal Processing Device), one or more PLDs (Programmable Logic Device) or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102, 202. Description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure may be implemented by using a firmware or a software and a firmware or a software may be implemented to include a module, a procedure, a function, etc. A firmware or a software configured to perform description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure may be included in one or more processors 102, 202 or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. Description, functions, procedures, proposals, methods and/or operation flow charts disclosed in the present disclosure may be implemented by using a firmware or a software in a form of a code, a command and/or a set of commands.
One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, a signal, a message, information, a program, a code, an instruction and/or a command in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, a flash memory, a hard drive, a register, a cash memory, a computer readable storage medium and/or their combination. One or more memories 104, 204 may be positioned inside and/or outside one or more processors 102, 202. In addition, one or more memories 104, 204 may be connected to one or more processors 102, 202 through a variety of technologies such as a wire or wireless connection.
One or more transceivers 106, 206 may transmit user data, control information, a wireless signal/channel, etc. mentioned in methods and/or operation flow charts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receiver user data, control information, a wireless signal/channel, etc. mentioned in description, functions, procedures, proposals, methods and/or operation flow charts, etc. disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive a wireless signal. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information or a wireless signal to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information or a wireless signal from one or more other devices. In addition, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208 and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, a wireless signal/channel, etc. mentioned in description, functions, procedures, proposals, methods and/or operation flow charts, etc. disclosed in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., an antenna port). One or more transceivers 106, 206 may convert a received wireless signal/channel, etc. into a baseband signal from a RF band signal to process received user data, control information, wireless signal/channel, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, a wireless signal/channel, etc. which are processed by using one or more processors 102, 202 from a baseband signal to a RF band signal. Therefor, one or more transceivers 106, 206 may include an (analogue) oscillator and/or a filter.
Embodiments described above are that elements and features of the present disclosure are combined in a predetermined form. Each element or feature should be considered to be optional unless otherwise explicitly mentioned. Each element or feature may be implemented in a form that it is not combined with other element or feature. In addition, an embodiment of the present disclosure may include combining a part of elements and/or features. An order of operations described in embodiments of the present disclosure may be changed. Some elements or features of one embodiment may be included in other embodiment or may be substituted with a corresponding element or a feature of other embodiment. It is clear that an embodiment may include combining claims without an explicit dependency relationship in claims or may be included as a new claim by amendment after application.
It is clear to a person skilled in the pertinent art that the present disclosure may be implemented in other specific form in a scope not going beyond an essential feature of the present disclosure. Accordingly, the above-described detailed description should not be restrictively construed in every aspect and should be considered to be illustrative. A scope of the present disclosure should be determined by reasonable construction of an attached claim and all changes within an equivalent scope of the present disclosure are included in a scope of the present disclosure.
A scope of the present disclosure includes software or machine-executable commands (e.g., an operating system, an application, a firmware, a program, etc.) which execute an operation according to a method of various embodiments in a device or a computer and a non-transitory computer-readable medium that such a software or a command, etc. are stored and are executable in a device or a computer. A command which may be used to program a processing system performing a feature described in the present disclosure may be stored in a storage medium or a computer-readable storage medium and a feature described in the present disclosure may be implemented by using a computer program product including such a storage medium. A storage medium may include a high-speed random-access memory such as DRAM, SRAM, DDR RAM or other random-access solid state memory device, but it is not limited thereto, and it may include a nonvolatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices or other nonvolatile solid state storage devices. A memory optionally includes one or more storage devices positioned remotely from processor(s). A memory or alternatively, nonvolatile memory device(s) in a memory include a non-transitory computer-readable storage medium. A feature described in the present disclosure may be stored in any one of machine-readable mediums to control a hardware of a processing system and may be integrated into a software and/or a firmware which allows a processing system to interact with other mechanism utilizing a result from an embodiment of the present disclosure. Such a software or a firmware may include an application code, a device driver, an operating system and an execution environment/container, but it is not limited thereto.
Here, a wireless communication technology implemented in a wireless device 100, 200 of the present disclosure may include Narrowband Internet of Things for a low-power communication as well as LTE, NR and 6G. Here, for example, an NB-IoT technology may be an example of a LPWAN (Low Power Wide Area Network) technology, may be implemented in a standard of LTE Cat NB1 and/or LTE Cat NB2, etc. and is not limited to the above-described name. Additionally or alternatively, a wireless communication technology implemented in a wireless device 100, 200 of the present disclosure may perform a communication based on a LTE-M technology. Here, in an example, a LTE-M technology may be an example of a LPWAN technology and may be referred to a variety of names such as an eMTC (enhanced Machine Type Communication), etc. For example, an LTE-M technology may be implemented in at least any one of various standards including 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) LTE M and so on and it is not limited to the above-described name. Additionally or alternatively, a wireless communication technology implemented in a wireless device 100, 200 of the present disclosure may include at least any one of a ZigBee, a Bluetooth and a low power wide area network (LPWAN) considering a low-power communication and it is not limited to the above-described name. In an example, a ZigBee technology may generate PAN (personal area networks) related to a small/low-power digital communication based on a variety of standards such as IEEE 802.15.4, etc. and may be referred to as a variety of names.
A method proposed by the present disclosure is mainly described based on an example applied to 3GPP LTE/LTE-A, 5G system, but may be applied to various wireless communication systems other than the 3GPP LTE/LTE-A, 5G system.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0103205 | Aug 2021 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/010269 | 7/14/2022 | WO |
