CN116584055A - Apparatus and method for inter-cell interference control in a wireless communication system - Google Patents
Apparatus and method for inter-cell interference control in a wireless communication system Download PDFInfo
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Abstract
The present disclosure relates to a 5G communication system and an internet of things communication technology supporting higher data rates after fusing 4G systems and a system thereof. Based on 5G communication technology and IoT-related technology, the present disclosure may be applied to smart services (e.g., smart homes, smart buildings, smart cities, smart or networked automobiles, healthcare, digital education, retail, security and safety-related services, etc.). In addition, the present disclosure relates to a method and apparatus for performing communication in a wireless communication system including a plurality of cells.
Description
Technical Field
The present disclosure relates generally to methods and apparatus for performing communication in a wireless communication system including a plurality of cells.
Background
In order to meet the increasing demand for wireless data services since the deployment of fourth generation (4G) communication systems, efforts have been made to develop improved fifth generation (5G) or pre-5G communication systems. Thus, a 5G or pre-5G communication system is also referred to as a "beyond 4G network" communication system or a "Long Term Evolution (LTE) after" system. A 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band (e.g., 60 gigahertz (GHz) band) in order to achieve a higher data rate. In order to reduce propagation loss of radio waves and increase transmission distance, beamforming, massive Multiple Input Multiple Output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, massive antenna techniques are discussed in 5G communication systems.
Further, in 5G communication systems, development of system network improvement is underway based on advanced small cells, cloud Radio Access Networks (RANs), ultra dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and receiving-end interference cancellation. Hybrid Frequency Shift Keying (FSK) and Quadrature Amplitude Modulation (QAM) (FQAM), sliding Window Superposition Coding (SWSC), as Advanced Code Modulation (ACM), and Filter Bank Multicarrier (FBMC), non-orthogonal multiple access (NOMA), and Sparse Code Multiple Access (SCMA), as advanced access technologies, have also been developed in 5G systems.
The internet is now evolving towards the internet of things (IoT) where distributed entities, such as things, exchange and process information without human intervention. Through a connection with a cloud server, internet of everything (IoE) combining IoT technology and big data processing technology has emerged. As IoT implementations require technical elements such as "sensing technology," "wireless communication and network infrastructure," "wired communication and network infrastructure," "service interface technology," and "security technology," sensor networks, machine-to-machine (M2M) communications, and Machine Type Communications (MTC) have recently been studied. Such IoT environments may provide intelligent internet technology services in which new value is created for human life by collecting and analyzing data generated between the interconnects. With the convergence and integration between existing Information Technology (IT) and various industrial applications, ioT may be applied in a variety of fields including smart homes, smart buildings, smart cities, smart cars or networking cars, smart grids, healthcare, smart appliances, and advanced medical services.
Various attempts have been made to apply 5G communication systems to IoT networks. For example, techniques such as sensor networks, MTC, and M2M communication may be implemented by beamforming, MIMO, and array antennas. The application of cloud Radio Access Networks (RANs) as the big data processing technology described above may also be considered as an example of the fusion of 5G technology with IoT technology.
For coexistence between LTE and New Radio (NR) (LTE-NR coexistence), NR provides NR User Equipments (UEs) with the functionality to configure a pattern of cell-specific reference signals (CRSs) for LTE. In a single Transmit and Receive Point (TRP) configured UE, only one CRS pattern may be configured per LTE carrier. Thus, if neighboring LTE cell(s) use a different CRS pattern than the UE's serving cell (LTE-NR co-existence cell) in a multi-cell environment, the UE may experience considerable interference from neighboring LTE cell(s). Regarding the above-described problems, interference to UEs may be reduced by proper scheduling of the base station, but there is a limit in that scheduling may be performed on a Resource Block (RB) by Resource Block (RB) basis and CRSs may be mapped on a Resource Element (RE) by Resource Element (RE) basis.
Disclosure of Invention
Technical problem
One aspect of the present disclosure is to provide a method and apparatus for efficiently providing a service.
Problem solution
The present invention aims to solve the above problems and disadvantages and to provide at least the advantages described below.
According to one aspect of the present disclosure, a method performed by a terminal in a communication system is provided. The method includes receiving configuration information associated with a CRS pattern of a cell from a base station via higher layer signaling; determining REs of the CRS based on the configuration information; determining whether a Physical Downlink Shared Channel (PDSCH) is received on REs of the CRS; PDSCH is received from the base station based on the determination, wherein PDSCH is received by performing interference cancellation in a case where PDSCH is received on REs of CRS.
According to another aspect of the present disclosure, a terminal in a communication system is provided. The terminal includes a transceiver; and a controller configured to: receiving configuration information associated with a CRS pattern of a cell from a base station via higher layer signaling; determining REs of the CRS based on the configuration information; determining whether the PDSCH is received on REs of the CRS, receiving the PDSCH from the base station based on the determination, wherein the PDSCH is received by performing interference cancellation in a case where the PDSCH is received on REs of the CRS.
According to another aspect of the present disclosure, a method performed by a base station in a communication system is provided. The method includes transmitting configuration information associated with a CRS pattern of a cell to a terminal via higher layer signaling; determining REs of the CRS based on the configuration information; determining whether to transmit PDSCH on REs of CRS; and transmitting a PDSCH to the terminal based on the determination.
According to another aspect of the present disclosure, a base station in a communication system is provided. The base station includes a transceiver; and a controller configured to: transmitting configuration information associated with a CRS pattern of a cell to a terminal via higher layer signaling; determining REs of the CRS based on the configuration information; determining whether to transmit PDSCH on REs of CRS; and transmitting a PDSCH to the terminal based on the determination.
Advantageous effects of the invention
According to the disclosed embodiments, services can be efficiently provided in a wireless communication system in which NR and LTE networks coexist.
Drawings
The foregoing and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following description, taken in conjunction with the accompanying drawings, in which:
fig. 1 is a diagram showing a basic structure of a time-frequency domain, which is a radio resource domain for transmitting data or control channels in a 5G system, according to an embodiment;
fig. 2 is a diagram showing an example of a slot structure considered in a 5G system according to an embodiment;
fig. 3 is a diagram illustrating an example of configuring a bandwidth part (BWP) in a 5G communication system according to an embodiment;
fig. 4 is a diagram illustrating an example of a control resource set (CORESET) over which a downlink control channel is transmitted in a 5G wireless communication system according to an embodiment;
Fig. 5 is a diagram showing an example of a basic unit constituting time and frequency resources of a downlink control channel that can be used in 5G according to an embodiment;
fig. 6 is a diagram illustrating a method of a base station and a UE to transmit and receive data considering a downlink data channel and rate matching resources according to an embodiment;
fig. 7A is a diagram for illustrating an example of an operation of a base station in a wireless communication system according to an embodiment;
fig. 7B is a diagram for illustrating an example of an operation of a UE in a wireless communication system according to an embodiment;
fig. 8 is a diagram showing an example of an operation of a UE in a wireless communication system according to an embodiment;
fig. 9A is a diagram for illustrating an example of an operation of a base station in a wireless communication system according to an embodiment;
fig. 9B is a diagram for illustrating an example of an operation of a UE in a wireless communication system according to an embodiment;
fig. 10A is a diagram for illustrating an example of an operation of a UE in a wireless communication system according to an embodiment;
fig. 10B is a diagram for illustrating an example of an operation of a UE in a wireless communication system according to an embodiment;
fig. 11 is a diagram for illustrating an example of an operation of a UE in a wireless communication system according to an embodiment;
fig. 12 is a block diagram of a UE according to an embodiment; and
Fig. 13 is a block diagram of a base station according to an embodiment.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
According to the disclosed embodiments, services can be efficiently provided in a wireless communication system in which NR and LTE networks coexist.
In describing embodiments of the present disclosure, descriptions related to technical contents well known in the art and not directly related to the present disclosure will be omitted. Unnecessary descriptions are omitted so as to prevent obscuring the main idea of the present disclosure and to more clearly convey the main idea.
For the same reason, in the drawings, some elements may be exaggerated, omitted, or schematically shown. Furthermore, the size of each element does not fully reflect the actual size. In the drawings, identical or corresponding elements have identical reference numerals.
The advantages and features of the present disclosure and the manner in which they are accomplished will become apparent by reference to the embodiments that are described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but may be implemented in various forms. The following examples are provided solely for the purpose of fully disclosing the present disclosure and informing those skilled in the art the scope of the present disclosure and are limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements. Further, in describing the present disclosure, a detailed description of known functions or configurations incorporated herein will be omitted when it may be determined that the description may make the subject matter of the present disclosure unnecessarily unclear. The terms to be described below are terms defined in consideration of functions in the present disclosure, and may be different according to users, intention of users, or custom. Accordingly, the definition of the terms should be based on the contents of the entire specification.
In the following description, a base station is an entity that allocates resources to a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS, a radio access unit, a base station controller, and a Node on a network. A terminal may include a UE, a Mobile Station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, "downlink" refers to a radio link through which a base station transmits signals to a terminal, and "uplink" refers to a radio link through which a terminal transmits signals to a base station. Furthermore, although the following description may be directed to an LTE or LTE-advanced (LTE-a) system by way of example, embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types as the embodiments of the present disclosure. Examples of other communication systems may include 5G mobile communication technology (5G NR) developed outside LTE-a, and in the following description, "5G" may be a concept covering existing LTE, LTE-a, and other similar services. Further, based on the determination by those skilled in the art, the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure.
Here, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer-usable or computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.
Furthermore, each block of the flowchart illustrations may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.
As used herein, a "unit" refers to a software element or a hardware element, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), that performs a predetermined function. However, the "unit" does not always have a meaning limited to software or hardware. The "unit" may be configured to be stored in an addressable storage medium or to execute one or more processors. Thus, a "unit" includes, for example, a software element, an object-oriented software element, a class or task element, a process, a function, an attribute, a procedure, a subroutine, a program code segment, a driver, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by the "unit" may be combined into a smaller number of elements or divided into a larger number of elements. Furthermore, the elements and "units" may be implemented to replicate one or more Central Processing Units (CPUs) within a device or secure multimedia card. Further, a "unit" may include one or more processors.
Wireless communication systems have evolved from providing initial voice-oriented services to broadband wireless communication systems providing high speed and high quality packet data services, such as High Speed Packet Access (HSPA) in the third generation partnership project (3 GPP), LTE or evolved universal terrestrial radio access (E-UTRA), LTE-A, LTE-pro, high Rate Packet Data (HRPD) in 3GPP2, ultra Mobile Broadband (UMB), and communication standards such as 802.16E of the Institute of Electrical and Electronics Engineers (IEEE).
In an LTE system, which is a representative example of a broadband wireless communication system, in a downlink, an Orthogonal Frequency Division Multiplexing (OFDM) scheme is employed, and in an uplink, a single carrier frequency division multiple access (SC-FDMA) scheme is employed. The uplink refers to a radio link in which a UE (or MS) transmits data or control signals to a base station (or eNode B), and the downlink refers to a radio link in which a base station transmits data or control signals to a UE. The above-described multiple access method allows distinguishing the data or control information of each user so as not to overlap with each other by allocating and operating time-frequency resources to which the data or control information of each user is to be transmitted, thereby establishing orthogonality.
A 5G communication system, which is a communication system after LTE, must support services that simultaneously satisfy various demands, so that various demands from users and service providers can be freely reflected. Services considered by 5G communication systems include enhanced mobile broadband (emmbb), mass machine type communication (emtc), and Ultra Reliable Low Latency Communication (URLLC).
The emmbb is intended to provide a higher data transmission rate than the data transmission rate supported by the existing LTE, LTE-a or LTE-Pro. For example, in a 5G communication system, from the perspective of one base station, an eMBB should be able to provide a peak data rate of 20 gigabits per second (Gbps) in the downlink and 10Gbps in the uplink. Furthermore, the 5G communication system must provide both the peak data rate of the UE and the increased user perceived data rate. To meet such requirements, various transmission/reception techniques are demanded to be improved, including more advanced multi-antenna (multiple input multiple output (MIMO)) transmission techniques. Further, in the LTE system, a transmission bandwidth of up to 20 megahertz (MHz) is used in a 2 gigahertz (GHz) band to transmit signals, and the 5G communication system can satisfy a data transmission rate required for the 5G communication system by using a frequency bandwidth wider than 20MHz in a band of 3 to 6GHz or more.
Meanwhile, mctc is considering supporting application services such as IoT in 5G communication systems. In order to effectively provide IoT, mctc requires access support for large-scale UEs within a cell, improved UE coverage, increased battery life, and reduced UE cost. Because IoT is attached to various sensors and various devices to provide communication functionality, ioT must be able to support many UEs within a cell (e.g., 1,000,000 UEs per square kilometer (km) 2 )). In addition, because of the support of mMTCIs likely to be in a shadow area where the cell cannot cover, such as a basement of a building, a wider coverage may be required due to the nature of the service compared to other services provided by the 5G communication system. UEs supporting mctc must be low cost UEs and may require very long battery life, such as 10 to 15 years, because it is difficult to replace the battery of the UE frequently.
Finally, URLLC is a cellular-based wireless communication service that is used for specific purposes (mission critical). For example, services for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare or emergency alerts may be considered. Thus, the communication provided by URLLC must provide very low latency and very high reliability. For example, a service supporting URLLC must meet a null delay of less than 0.5 milliseconds (ms) while must meet 10 -5 Or lower packet error rate requirements. Thus, for services supporting URLLC, 5G communication systems must provide smaller Transmission Time Intervals (TTIs) than other services, while wide resources must be allocated in the frequency band to ensure the reliability of the communication link.
Three services of a 5G communication system, namely, emmbb, URLLC, and mctc, can be multiplexed and transmitted in one system. In this case, different transmission/reception techniques and transmission/reception parameters may be used between services to satisfy different requirements of each service. The 5G is not limited to the above three services.
Hereinafter, a frame structure of the 5G system will be described in more detail with reference to the accompanying drawings.
Fig. 1 is a diagram illustrating a basic structure of a time-frequency domain, which is a radio resource domain transmitting data or control information in a 5G communication system, according to an embodiment.
Referring to fig. 1, the horizontal and vertical axes represent time and frequency domains, respectively. The basic unit of resources in the time and frequency domains is an RE 101, and the RE 101 may be defined as one OFDM symbol 102 on the time axis and may be defined as one subcarrier 103 on the frequency axis. In the frequency domain of the power supply,(e.g., 12) consecutive REs may configure one RB 104.
Fig. 2 is a diagram illustrating a slot structure considered in a 5G communication system according to an embodiment.
Fig. 2 shows an example of the structure of a frame 200, a subframe 201, and a slot 202.
Referring to fig. 2, one frame 200 may be defined as 10ms. One subframe 201 may be defined as 1ms, in which case one frame 200 may be composed of a total of 10 subframes 201. Slots 202 and 203 may be defined as 14 OFDM symbols (i.e., the number of symbols per slot =14). One subframe 201 may include one or more slots 202 and 203, and the number of slots 202 and 203 of each subframe 201 may vary according to a set value μ of a subcarrier spacing, where μ=0 at reference numeral 204 and μ=1 at reference numeral 205. One subframe 201 may include one slot 202 when μ=0 204, and one subframe 201 may include two slots 203 when μ=1 205. That is, the number of slots per subframe +.>Can be varied and accordingly the number of time slots per frame +.>May vary. Setting a value μ +_ according to each subcarrier spacing>And->May be defined in table 1 below.
TABLE 1
Next, a BWP configuration in the 5G communication system will be described in detail with reference to fig. 3.
Fig. 3 is a diagram illustrating an example of configuring BWP of the 5G communication system according to an embodiment.
Fig. 3 shows an example in which the UE bandwidth 300 is configured as two BWP, bwp#1 301 and bwp#2 302. The base station may configure one or more BWP for the UE and may configure information as shown in table 2 below for each BWP.
TABLE 2
Not limited to the above example, various parameters related to BWP may be configured in the UE in addition to the above configuration information. The above information may be transmitted by the base station to the UE through higher layer signaling, e.g., radio Resource Control (RRC) signaling. At least one BWP of the one or more configured BWP may be activated. Whether or not the configured BWP is activated may be semi-statically transmitted from the base station to the UE through RRC signaling, or may be dynamically transmitted through Downlink Control Information (DCI). Prior to RRC connection, the UE may receive a configuration of an initial BWP for initial connection from the base station through a Master Information Block (MIB). More specifically, in the initial access step, the UE may receive configuration information of CORESET through which a Physical Downlink Control Channel (PDCCH) for receiving system information (e.g., remaining system information (RMSI) or system information block (SIB 1)) required for initial access may be transmitted. The UE may also receive the search space through the MIB. The CORESET and search space of the MIB configuration may be considered ID 0. The base station may notify the UE of configuration information, such as frequency allocation information, time allocation information, and parameter sets of CORESET #0, through the MIB. In addition, the base station may notify the UE of configuration information about the monitoring period and timing of CORESET #0, i.e., configuration information about search space #0, through the MIB. The UE may consider the frequency domain configured as CORESET #0 obtained from the MIB as an initial BWP for initial access. In this case, the ID of the initial BWP may be regarded as 0.
The configuration of 5G supported BWP may be used for various purposes.
When the bandwidth supported by the UE is smaller than the system bandwidth, the UE may be supported through a BWP configuration. For example, the base station may configure the frequency location of BWP (configuration information 2) for the UE so that the UE may transmit and receive data at a specific frequency location within the system bandwidth.
Furthermore, to support different parameter sets, the base station may configure the UE with a plurality of BWP. For example, to support the transmission and reception of data to any UE using a 15 kilohertz (kHz) subcarrier spacing and a 30 kHz subcarrier spacing, two BWPs may be configured to be 15 kHz and 30 kHz subcarrier spacing, respectively. Different BWPs may be Frequency Division Multiplexed (FDM), and when data is transmitted/received with a specific subcarrier spacing, BWPs configured for the corresponding subcarrier spacing may be activated.
Further, in order to reduce power consumption of the UE, the base station may configure the UE with BWP having different bandwidths. For example, when a UE supports a very large bandwidth (e.g., a bandwidth of 100 MHz) and always transmits and receives data using the corresponding bandwidth, a large amount of power may be consumed. In particular, without traffic, monitoring the downlink control channel over an unnecessarily large bandwidth of 100MHz is very inefficient in terms of power consumption for the UE. In order to reduce power consumption of the UE, the base station may configure the UE with a relatively small BWP, e.g., a 20MHz BWP. In the absence of traffic, the UE may monitor in BWP of 20MHz, and when generating data, the UE may transmit/receive data using BWP of 100MHz according to an instruction of the base station.
In the method of configuring BWP, the UE before RRC connection may receive configuration information of the initial BWP through the MIB in an initial access step. More specifically, the UE may receive a configuration of CORESET for a downlink control channel (PBCH) through which DCI of a scheduling SIB may be transmitted from MIB of the Physical Broadcast Channel (PBCH). The bandwidth of CORESET configured through MIB may be regarded as initial BWP, and through the configured initial BWP, the UE may receive PDSCH through which SIB is transmitted. In addition to the purpose of receiving SIBs, the initial BWP may be used for Other System Information (OSI), paging, and random access.
Next, a Synchronization Signal (SS)/PBCH block in 5G will be described.
The SS/PBCH block may refer to a physical layer channel block composed of a primary SS (PSS), a Secondary SS (SSs), and a PBCH. Specifically, PSS, SSS, PBCH and SS/PBCH may be defined as follows:
-PSS: serving as a reference for downlink time/frequency synchronization and providing some information about the cell ID.
SSS: used as a reference for downlink time/frequency synchronization and provides the remaining cell ID information not provided by the PSS. In addition, SSS may be used as a reference signal for demodulating PBCH.
-PBCH: basic system information required for transmitting and receiving a data channel and a control channel of a UE is provided. The basic system information may include search space related control information indicating radio resource mapping information of the control channel, and scheduling control information on a separate data channel for transmitting the system information.
-SS/PBCH block: the SS/PBCH block consists of a combination of PSS, SSs and PBCH. One or more SS/PBCH blocks may be transmitted within 5ms, and each transmitted SS/PBCH block may be distinguished by an index.
The UE may detect PSS and SSS in an initial access phase and may decode PBCH. The UE may obtain MIB from the PBCH and may receive CORESET #0 (which may correspond to CORESET with CORESET index 0) thus configured. The UE may perform monitoring on CORESET #0 assuming that the selected SS/PBCH block and a demodulation reference signal (DMRS) transmitted from CORESET #0 are quasi co-located (QCL). The UE may receive system information transmitted from CORESET #0 as DCI. The UE may obtain Random Access Channel (RACH) related configuration information required for initial access from the received system information. In view of the selected SS/PBCH index, the UE may transmit a Physical RACH (PRACH) to the base station, and the base station receiving the PRACH may obtain information about the SS/PBCH block index selected by the UE. The base station may examine which block the UE selects from each SS/PBCH block and may recognize the fact that CORESET #0 associated with the selected block is monitored.
Next, DCI in the 5G communication system will be described in detail.
In the 5G communication system, scheduling information for uplink data (or Physical Uplink Shared Channel (PUSCH)) or downlink data (or PDSCH) may be transmitted from a base station to a UE through DCI. For PUSCH or PDSCH, the UE may monitor DCI formats for fallback and DCI formats for non-fallback. The DCI format for fallback may include a fixed field predefined between the base station and the UE, and the DCI format for non-fallback may include a configurable field.
After the channel coding and modulation procedure, DCI may be transmitted through the PDCCH. A Cyclic Redundancy Check (CRC) is attached to the DCI message payload, and the CRC may be scrambled with a Radio Network Temporary ID (RNTI) corresponding to an identity of the UE. Different RNTIs are used depending on the purpose of the DCI message (e.g., UE-specific data transmission, power control commands, or random access response). That is, the RNTI is not explicitly transmitted, but is included in the CRC calculation process and transmitted. When receiving a DCI message transmitted through a PDCCH, the UE recognizes the CRC using the allocated RNTI, and if the CRC recognition result is correct, the UE may recognize that the message has been transmitted to the UE.
For example, DCI scheduling PDSCH for System Information (SI) may be scrambled with SI-RNTI. DCI scheduling PDSCH for a Random Access Response (RAR) message may be scrambled with RA-RNTI. DCI scheduling a PDSCH for a paging message may be scrambled with a P-RNTI. The DCI informing of the Slot Format Indicator (SFI) may be scrambled with the SFI-RNTI. The DCI informing of Transmit Power Control (TPC) may be scrambled with a TPC-RNTI. The DCI for scheduling the UE-specific PDSCH or PUSCH may be scrambled with a cell-RNTI (C-RNTI).
DCI format 0_0 may be used as a backoff DCI for scheduling PUSCH, and in this case, CRC may be scrambled with C-RNTI. The DCI format 0_0 with CRC scrambled with the C-RNTI may include information as shown in table 3 below, for example.
TABLE 3
DCI format 0_1 may be used as non-fallback DCI for scheduling PUSCH, and in this case, CRC may be scrambled with C-RNTI. The DCI format 0_1 with CRC scrambled with the C-RNTI may include information as shown in table 4 below, for example.
TABLE 4
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The DCI format 1_0 may be used as a fallback DCI for scheduling a PDSCH, and in this case, the CRC may be scrambled with the C-RNTI. The DCI format 1_0 with CRC scrambled with the C-RNTI may include information as shown in table 5 below, for example.
TABLE 5
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DCI format 1_1 may be used as non-fallback DCI for scheduling PDSCH, and in this case, CRC may be scrambled with C-RNTI. The DCI format 1_1 with CRC scrambled with the C-RNTI may include information as shown in table 6 below.
TABLE 6
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Hereinafter, a method of allocating time domain resources for a data channel in a 5G communication system will be described.
The base station may configure the UE with a table of time domain resource allocation information for a downlink data channel (e.g., PDSCH) and an uplink data channel (e.g., PUSCH) through higher layer signaling (e.g., RRC signaling). The base station may configure a table consisting of maximum maxNrofDL-allocations=16 entries for PDSCH, and may configure a table consisting of maximum maxNrofDL-allocations=16 entries for PUSCH. The time domain resource allocation information may include, for example, PDCCH to PDSCH slot timing (corresponding to a time interval in units of slots between a time when the PDCCH is received and a time when the PDSCH scheduled by the received PDCCH is transmitted, denoted by K0) or PDCCH to PUSCH slot timing (corresponding to a time interval in units of slots between a time when the PDCCH is received and a time when the PUSCH scheduled by the received PDCCH is transmitted, denoted by K2), information on a position and a length of a starting symbol in which the PDSCH or PUSCH is scheduled in a slot, and a mapping type of the PDSCH or PUSCH. For example, the information shown in the following table 7 may be notified from the base station to the UE, and the information shown in the following table 8 may be notified from the UE to the base station.
TABLE 7
TABLE 8
The base station may inform the UE of one of the entries in the table of time domain resource allocation information (e.g., the base station is indicated with a "time domain resource allocation" field in the DCI) through L1 signaling (e.g., DCI). The UE may obtain time domain resource allocation information of PDSCH or PUSCH based on DCI received from the base station.
Hereinafter, a method of allocating frequency domain resources for a data channel in a 5G communication system will be described.
In 5G, resource allocation type 0 and resource allocation type 1 are supported as a method of indicating frequency domain resource allocation information of a downlink data channel (e.g., PDSCH) and an uplink data channel (e.g., PUSCH).
Resource allocation type 0
The RB allocation information may be notified from the base station to the UE in the form of a bitmap of RB groups (RBGs). In this case, the RBG may be composed of a set of consecutive VRBs, and the Size P of the RBG may be determined based on a value configured by a higher layer parameter (RBG-Size) and a Size value of BWP defined in table 9 below.
TABLE 9
| BWP size | Configuration 1 | Configuration 2 |
| 1-36 | 2 | 4 |
| 37-72 | 4 | 8 |
| 73-144 | 8 | 16 |
| 145-275 | 16 | 16 |
Nominal RBG size P
The size is as followsIs the total number (N) of RBGs of BWP i RBG ) The following can be defined based on equation (1):
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wherein the first RBG is of the size ofIf it isThe last RBG is of the size of Otherwise P, and all other RBGs are P in size.
N RBG Each bit of the bit-sized bitmap may correspond to each RBG. The RBGs may be indexed in order of increasing frequency starting from the lowest frequency location of the BWP. For N in BWP RBG RBGs rbg#0 to rbg# (N RBG -1) mapping from Most Significant Bits (MSBs) to Least Significant Bits (LSBs) of the RBG bitmap. When the specific bit value in the bitmap is 1, the UE may determine that the RBG corresponding to the bit value is allocated, and when the specific bit value in the bitmap is 0, the UE may determine that the RBG corresponding to the bit value is not allocated.
Resource allocation type 1
RB allocation information may be notified from the base station to the UE as information on the start position and length of the continuously allocated VRBs. In this case, interleaving or non-interleaving may be additionally applied to the consecutively allocated VRBs. The resource allocation field of resource allocation type 1 may be composed of a Resource Indication Value (RIV), which may be composed of a start point (RB) of the VRB start ) And the length (L) of the continuously allocated RBs RBs ) Composition is prepared. More specifically, the size isRIV of BWP of (B-WP)The following can be defined:
if it isThen
Otherwise
Wherein L is RBs 1 and will not exceed
Hereinafter, a downlink control channel in a 5G communication system will be described in more detail with reference to the accompanying drawings.
Fig. 4 is a diagram illustrating an example of CORESET in which a downlink control channel is transmitted in a 5G wireless communication system, according to an embodiment.
Referring to fig. 4, the ue BWP 410 is configured on the frequency axis, and two control sets, CORESET #1 401 and CORESET #2 402, are configured in one slot 420 on the time axis. CORESET 401 and 402 may be configured to specific frequency resources 403 within the entire UE BWP 410 on the frequency domain. One or more OFDM symbols may be configured in the time domain and this may be defined as a CORESET duration 404. Referring to the example shown in fig. 4, CORESET #1 401 may be configured to a CORESET length of 2 symbols, and CORESET #2 402 may be configured to a CORESET length of 1 symbol.
CORESET in 5G above may be configured to the UE by the base station through higher layer signaling (e.g., system information, MIB, or RRC signaling). Configuring CORESET for UE refers to providing information such as CORESET ID, CORESET frequency location, and CORESET symbol length. For example, table 10 below shows information provided for configuring CORESET.
TABLE 10
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In table 10, TCI-statepdcch (transmission configuration indication (TCI) status) configuration information may include information about one or more SS/PBCH block indexes in QCL relation to DMRS transmitted in a corresponding CORESET or CSI-RS index.
Fig. 5 is a diagram showing an example of a basic unit constituting time and frequency resources of a downlink control channel that can be used in 5G according to an embodiment.
Referring to fig. 5, a basic unit of time and frequency resources constituting a control channel may be referred to as a Resource Element Group (REG) 503, and the REG 503 may be defined as 1 OFDM symbol 501 on a time axis and 1 Physical Resource Block (PRB) 502, i.e., 12 subcarriers, on a frequency axis. The base station may configure the downlink control channel allocation unit by concatenating REGs 503.
As shown in fig. 5, a basic unit to which a downlink control channel is allocated in a 5G communication system is referred to as a Control Channel Element (CCE) 504, and one CCE 504 may be composed of a plurality of REGs 503. Describing the REGs 503 shown in fig. 5, the REGs 503 may be composed of 12 REs, and if 1 CCE 504 is composed of 6 REGs 503, 1 CCE 504 may be composed of 72 REs. When configuring downlink CORESET, the corresponding region may be composed of a plurality of CCEs 504, and a specific downlink control channel is mapped to one or more CCEs 504 and transmitted according to an Aggregation Level (AL) in the control region. The plurality of CCEs 504 in CORESET may be allocated according to a logical mapping method.
The basic unit of the downlink control channel (i.e., REG 503 shown in fig. 5) may include REs to which DCI is mapped and regions to which DMRS, which is an RS for decoding the REs, are mapped. As shown in fig. 5, 3 DMRSs 505 may be transmitted within one REG 503. The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on AL, and link adaptation of the downlink control channel may be achieved using a different number of CCEs. For example, when al=l, one downlink control channel may be transmitted through L CCEs. The UE may need to detect the signal without calculating the information on the downlink control channel and for blind decoding a search space indicating the set of CCEs may be defined. Because the search space may be a set of downlink control channel candidates including CCEs that the UE should attempt to decode at a given aggregation level, and there are several aggregation levels making up one bundle with 1, 2, 4, 8, or 16 CCEs, the UE may have multiple search spaces. A set of search spaces may be defined as a set of search spaces at the aggregate level of all configurations.
The search space may be classified into a common search space and a UE-specific search space. A UE of a certain group or all UEs may check a common search space of the PDCCH to receive cell common control information such as system information or dynamic scheduling of paging messages. By checking the common search space of the PDCCH, the UE may receive PDSCH scheduling allocation information for transmitting SIBs including operator information of the cell. In the case of a common search space, the common search space may be defined as a set of committed CCEs, since a certain group of UEs or all UEs must receive the PDCCH. The scheduling allocation information of the UE-specific PDSCH or PUSCH may be received by checking a UE-specific search space of the PDCCH. The UE-specific search space may be defined UE-specifically as a function of the identity of the UE and various system parameters.
In 5G, parameters of the search space for PDCCH may be configured from the base station to the UE through higher layer signaling (e.g., SIB, MIB and RRC signaling). The base station may configure the UE with the number of PDCCH candidates at each aggregation level L, a monitoring period of a search space, a monitoring occasion of a search space in symbol units in a slot, a search space type (common search space or UE-specific search space), a combination of DCI format and RNTI to be monitored in a corresponding search space, or a CORESET index of a search space for monitoring the UE. The parameters of the search space for the PDCCH may include information as shown in table 11 below.
TABLE 11
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Based on the configuration information, the base station may configure one or more search space sets for the UE. The base station may configure search space set 1 and search space set 2 for the UE. In search space set 1, the UE may be configured to monitor DCI format a scrambled with the X-RNTI in the common search space, and in search space set 2, the UE may be configured to monitor DCI format B scrambled with the Y-RNTI in the UE-specific search space. Depending on the configuration information, one or more sets of search spaces may exist in a common search space or a UE-specific search space. For example, search space set #1 and search space set #2 may be configured as a common search space, and search space set #3 and search space set #4 may be configured as UE-specific search spaces.
In the common search space, the following DCI format and RNTI combinations may be monitored. Not limited to the following examples.
-DCI format 0_0/1_0 with CRC scrambled by C-RNTI, configuration Scheduling (CS) -RNTI, SP-CSI-RNTI, random Access (RA) -RNTI, temporary Cell (TC) -RNTI, paging (P) -RNTI, system Information (SI) -RNTI
DCI format 2_0 with CRC scrambled by SFI-RNTI
DCI format 2_1 with CRC scrambled by Interrupt (INT) -RNTI
DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI
DCI format 2_3 with CRC scrambled by RNTI TPC-SRS
In the UE-specific search space, the following DCI format and RNTI combinations may be monitored. Not limited to the following examples.
DCI Format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI
DCI format 1_0/1_1, RNTI with CRC designation scrambled by C-RNTI, CS-RNTI, TC-RNTI may follow the following definition and use.
C-RNTI: UE-specific PDSCH scheduling purposes
TC-RNTI: UE-specific PDSCH scheduling purposes
CS-RNTI: semi-statically configured UE-specific PDSCH scheduling purposes
RA-RNTI: PDSCH scheduling purposes at random access phase
P-RNTI: PDSCH scheduling purposes for transmitting pages
SI-RNTI: PDSCH scheduling purpose for transmitting system information
RNTI inter frames: for indicating whether PDSCH is punctured or not
TPC-PUSCH-RNTI: power control commands for indicating PUSCH
TPC-PUCCH-RNTI: power control commands for indicating PUCCH
TPC-SRS-RNTI: power control commands for indicating SRS
The DCI formats specified above may follow the definitions shown in table 12 below.
TABLE 12
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In 5G, the search space for aggregation level L in CORESET p and set of search spaces s may be represented by equation (2), as follows.
Wherein:
-L: aggregation level
-n CI : carrier cableGuiding device
-N CCE,p : controlling the total number of CCEs present in resource p
-n μ s,f : time slot index
-M (L) p,s,max : number of PDCCH candidates for aggregation level L
-m snCI ＝0,...,M (L) p,s,max -1: PDCCH candidate index of aggregation level L
-i＝0,...,L-1
-Y p，-1 ＝n RNTI ≠0，A 0 ＝39827，A 1 ＝39829，A 2 =39839, d=6553'; and is also provided with
-n RNTI : terminal identification
In the case of a common search space, Y_ (p, n μ s,f ) The value may correspond to 0.
In the case of a UE-specific search space, y_ (p, n μ s,f ) The value may correspond to a value that varies depending on the identity of the UE (C-RNTI or ID configured by the base station for the UE) and the time index.
In 5G, since multiple search space sets may be configured with different parameters (e.g., parameters in table 10), the set of search space sets monitored by the UE at each point in time may vary. For example, if search space set #1 is configured as an X slot period and search space set #2 is configured as a Y slot period, and X and Y are different, the UE may monitor both search space set #1 and search space set #2 in a specific slot and may monitor one of search space set #1 and search space set #2 in another specific slot.
When multiple sets of search spaces are configured to a UE, the following conditions may be considered in a method for determining a set of search spaces to be monitored by the UE.
[ condition 1: limiting the maximum number of PDCCH candidates
The number of PDCCH candidates that can be monitored per slot does not exceed M μ 。M μ May be defined as being configured with a subcarrier spacing of 15 + -2 μ The maximum number of PDCCH candidates per slot in a kHz cell, and may be defined in table 13 below.
TABLE 13
| μ | Maximum number of PDCCH candidates per slot and per serving cell (M μ ) |
| 0 | 44 |
| 1 | 36 |
| 2 | 22 |
| 3 | 20 |
[ condition 2: limiting the maximum number of CCEs ]
The number of CCEs constituting the entire search space (the total search space means the entire CCE set corresponding to the joint region of the plurality of search space sets) per slot does not exceed C μ 。C μ May be defined as being configured with a subcarrier spacing of 15 + -2 μ The maximum number of CCEs per slot in a kHz cell and may be defined in table 14 below.
TABLE 14
| μ | Maximum number of CCEs per slot and per serving cell (C μ ) |
| 0 | 56 |
| 1 | 56 |
| 2 | 48 |
| 3 | 32 |
For convenience of explanation, a case where the conditions 1 and 2 are simultaneously satisfied at a specific point in time is defined as "condition a". Therefore, the condition a being not satisfied may mean that at least one of the above-described conditions 1 and 2 is not satisfied.
Depending on the configuration of the search space set of base stations, condition a may not be satisfied at a particular point in time. If the condition a is not satisfied at a specific point of time, the UE may select and monitor only some search space sets configured to satisfy the condition a at the corresponding point of time, and the base station may transmit the PDCCH to the selected search space sets.
As a method of selecting some search spaces from the entire set of search spaces, the following method may be followed.
When condition a of the PDCCH is not satisfied at a specific time point (slot),
the UE (or the base station) may preferentially select a search space set in which a search space type is configured as a common search space from among search space sets existing at corresponding times, instead of a search space set configured as a UE-specific search space.
When all the sets of search spaces configured as a common search space are selected (i.e., if condition a is satisfied even after all the sets of search spaces configured as a common search space are selected), the UE (or the base station) may select the sets of search spaces configured as UE-specific search spaces. In this case, when there are a plurality of search space sets configured as UE-specific search spaces, a search space set having a low search space set index may have a higher priority. The UE (or base station) may select a set of UE-specific search spaces within the range that satisfies condition a in view of the priority.
In 5G, CORESET can be defined by N in the frequency domain RB CORESET Consist of RBs and can be composed of N in the time axis symb CORESET E {1,2,3} symbols. One CCE may consist of 6 REGs, and the REGs may be defined as 1 RB for 1 OFDM symbol. In one CORESET, REGs may be indexed in a time-first order, starting with REG index 0 (lowest RB) of the first OFDM symbol of CORESET.
In 5G, an interleaving method and a non-interleaving method are supported as transmission methods of PDCCHs. The base station may send the UE with an interlace or non-interlace of each CORESET through higher layer signaling configuration. Interleaving may be performed in units of REG bundles. A REG bundle may be defined as a set of one or more REGs. Based on whether the interleaving transmission configured from the base station is performed or the non-interleaving transmission, the UE may determine a CCE-to-REG mapping method in the corresponding CORESET in the following manner, as shown in table 15 below.
TABLE 15
Hereinafter, the rate matching operation and the puncturing operation will be described in detail.
When the time and frequency resource a transmitting an arbitrary symbol sequence a overlaps with the arbitrary time and frequency resource B, the rate matching or puncturing operation may be regarded as a transmission/reception operation of the channel a in consideration of the resource C in the region where the resource a and the resource B overlap. The specific operation may follow the following.
Rate matching operation
The base station may map and transmit channel a only for a remaining resource region except for resource C, which corresponds to a region overlapping with resource B, among all the resources a to be transmitted to the UE for the symbol sequence a. For example, when the symbol sequence a is composed of { symbol #1, symbol #2, symbol #3, and symbol #4}, resource a is { resource #1, resource #2, resource #3, and resource #4}, and resource B is { resource #3, and resource #5}, the base station may sequentially map the symbol sequence a to { resource #1, resource #2, and resource #4}, and { resource #1, resource #2, and resource #4} are the remaining resources of resource a except { resource #3} corresponding to resource C, and may transmit the symbol sequence a. As a result, the base station can map the symbol sequences { symbol #1, symbol #2, and symbol #3} to { resource #1, resource #2, and resource #4} and transmit them, respectively.
The UE may determine resources a and B according to scheduling information for the symbol sequence a from the base station, and through this, the UE may determine resource C, which is an area where the resources a and B overlap. The UE may receive the symbol sequence a assuming that the symbol sequence a is sequentially mapped to the remaining areas except for the resource C among all the resources a and transmitted. For example, when the symbol sequence a is composed of { symbol #1, symbol #2, symbol #3, and symbol #4}, resource a is { resource #1, resource #2, resource #3, and resource #4}, and resource B is { resource #3, and resource #5}, the UE may assume that the symbol sequence a is sequentially mapped to { resource #1, resource #2, resource #4} (which are the remaining resources of resource a except { resource #3} corresponding to resource C) for reception. As a result, the UE may assume that the symbol sequence { symbol #1, symbol #2, symbol #3} is mapped to { resource #1, resource #2, resource #4} and transmitted, and may perform a subsequent series of reception operations.
Perforating operation
When there is a resource C corresponding to an area overlapping with the resource B among all the resources a for transmitting the symbol sequence a to the UE, the base station may map the symbol sequence a to the entire resource a, but may not perform transmission in a resource area corresponding to the resource C, and may perform transmission only in the remaining resource areas except the resource C among the resources a. For example, when the symbol sequence a is composed of { symbol #1, symbol #2, symbol #3, and symbol #4}, the resource a is { resource #1, resource #2, resource #3, and resource #4}, and the resource B is { resource #3, and resource #5}, the base station may map the symbol sequence a { symbol #1, symbol #2, symbol #3, symbol #4} to the resource a { resource #1, resource #2, resource #3, resource #4}, respectively, may transmit only the symbol sequences { symbol #1, symbol #2, symbol #4}, of { resource #1, resource #2, resource #4} corresponding to { resource #3} of { resource C, except { resource #3} of the resource a, and may not transmit { symbol #3} mapped to { resource #3} corresponding to the resource C. As a result, the base station can map the symbol sequences { symbol #1, symbol #2, and symbol #4} to { resource #1, resource #2, and resource #4} and transmit the symbol sequences { symbol #1, symbol #2, and symbol #4}, respectively.
The UE may determine resources a and B according to scheduling information for the symbol sequence a from the base station, and by this, may determine resource C, which is an area where the resources a and B overlap. The UE may assume that symbol sequence a is mapped and transmitted in the remaining region except for resource C in all resources a to receive symbol sequence a. For example, when the symbol sequence a is composed of { symbol #1, symbol #2, symbol #3, and symbol #4}, the resource a is { resource #1, resource #2, resource #3, and resource #4}, and the resource B is { resource #3, and resource #5}, the UE may assume that the symbol sequences a { symbol #1, symbol #2, symbol #3, and symbol #4} are each mapped to the resource a { resource #1, resource #2, resource #3, and resource #4}, but { symbol #3} mapped to { resource #3} corresponding to the resource C is not transmitted, and may receive under the assumption that the symbol sequences { symbol #1, symbol #2, and symbol #4} corresponding to { resource #1, resource #2, and resource #4} are mapped and transmitted in the resource a, wherein { resource #1, resource #2, resource #4} are the remaining resources other than { resource #3 }. As a result, the UE may assume that the symbol sequence { symbol #1, symbol #2, symbol #3} is mapped to { resource #1, resource #2, resource #4} and transmitted, and may perform a subsequent series of reception operations.
Hereinafter, a method of configuring rate matching resources for rate matching purposes in a 5G communication system will be described. Rate matching refers to adjusting the size of a signal in consideration of the amount of resources capable of transmitting the signal. For example, the rate matching of the data channels may be sized accordingly without mapping and transmitting the data channels for a particular time and frequency resource region.
Fig. 6 is a diagram illustrating a method in which a base station and a UE transmit and receive data in consideration of a downlink data channel and rate matching resources according to an embodiment.
Referring to fig. 6, PDSCH 601 and rate matching resources 602 are shown. The base station may configure the rate matching resources 602 for the UE through higher layer signaling (e.g., RRC signaling). The rate matching resource 602 configuration information may include time domain resource allocation information 603, frequency domain resource allocation information 604, and period information 605. The bitmap corresponding to the frequency domain resource allocation information 604 may be referred to as a "first bitmap", the bitmap corresponding to the time domain resource allocation information 603 may be referred to as a "second bitmap", and the bitmap corresponding to the period information 605 may be referred to as a "third bitmap". When all or part of the time and frequency resources of the scheduled data channel 601 overlap with the set rate matching resources 602, the base station may rate match and transmit the data channel 601 in the rate matching resources 602 portion, and the UE may perform reception and decoding after assuming that the data channel 601 is rate matched in the rate matching resources 602 portion.
The base station may dynamically inform the UE through the DCI whether to rate match the data channel in the configured rate matching resource section through additional configuration (corresponding to the "rate matching indicator" in the DCI format described above). Specifically, the base station may select some configured rate matching resources and group them into rate matching resource groups, and may indicate whether the UE rate-matches the data channel of each rate matching resource group through DCI using a bitmap method. For example, when four rate matching resources (rmr#1, rmr#2, rmr#3, and rmr#4) are configured, the base station may configure rmg#1= { rmr#1, rmr#2} and rmg#2= { rmr#3, rmr#4} as a rate matching group, and may indicate to the UE whether rates match in rmg#1 and rmg#2, respectively, using a 2-bit bitmap in the DCI field. For example, "1" may be indicated when rate matching is to be performed, and "0" may be indicated when rate matching is not to be performed.
The 5G supports granularity of "RB symbol level" and "RE level" as a method of configuring the above-described rate matching resources for the UE. More specifically, the following configuration method may be followed.
RB symbol level
For each BWP configured through higher layer signaling, the UE may receive up to four ratevachpatterns, and one ratevachpattern may include the following.
As reserved resources in BWP, resources in which time and frequency resource areas corresponding to the reserved resources are configured as a combination of RB-level bitmap and symbol-level bitmap on the frequency axis may be included. The reserved resources may span one or two time slots. A time domain pattern (periodic and pattern) may be additionally configured in which time and frequency domains composed of each RB-level and symbol-level bitmap pair are repeated.
The resource regions may include time and frequency domain resource regions configured as CORESET in BWP, and resource regions corresponding to time domain modes configured as search space configurations, wherein in the time domain modes the resource regions are repeated.
RE level
The UE may receive the following configured through higher layer signaling.
As configuration information (LTE-CRS-to-matching around) for REs corresponding to the LTE CRS pattern, a port number (nrofCRS-Ports) and LTE-CRS-vshift(s) value (v-shift) of the LTE CRS, center subcarrier location information (carrier freqdl) of the LTE carrier from a reference frequency point (e.g., reference point a), bandwidth size (carrier bandwidth dl) information of the LTE carrier, and subframe configuration information (MBSFN-subframe configuration list) corresponding to a multicast-broadcast single frequency network (MBSFN-subframe). The UE may determine the location of the CRS in the NR slots corresponding to the LTE subframes based on the above information.
Configuration information of a set of resources corresponding to one or more ZP CSI-RS in BWP may be included.
Next, the rate matching procedure of the LTE CRS described above will be described in detail. For coexistence of LTE and NR (LTE-NR coexistence), NR provides NR UEs with the function of configuring CRS patterns of LTE. More specifically, the CRS pattern may be provided by RRC signaling including at least one parameter of a ServingCellConfig Information Element (IE) or ServingCellConfigCommon IE. Examples of such parameters may include lte-CRS-ToMatchAround, lte-CRS-Pattern List1-r16, lte-CRS-Pattern List2-r16, and CRS-RateMatch-PercoresETPoolIndex-r16.
Rel-15 NR provides the functionality in which one CRS pattern may be configured for each serving cell by the lte-CRS-to-matcharound parameter. In Rel-16 NR, the above functionality has been extended to be able to configure multiple CRS patterns per serving cell. More specifically, one CRS pattern per LTE carrier may be configured in a single TRP (transmission and reception point) configured UE, one CRS pattern per LTE carrier may be configured in a plurality of TRP configured UEs, and two CRS patterns per LTE carrier may be configured. For example, in a single TRP configured UE, each serving cell may configure up to three CRS patterns through the lte-CRS-Pattern List1-r16 parameters. Additionally or alternatively, CRS may be configured for each TRP in a UE configured with multiple TRPs. That is, CRS pattern for TRP1 may be configured by the lte-CRS-Pattern List1-r16 parameters, and CRS pattern for TRP2 may be configured by the lte-CRS-Pattern List2-r16 parameters. On the other hand, when two TRPs are configured as described above, whether the CRS patterns of both TRP1 and TRP2 are applied to a specific PDSCH or the CRS pattern of only one TRP is determined by the CRS-RateMatch-percoresetpoinlindex-r 16 parameter, and if the CRS-RateMatch-percoresetpoinlindex-r 16 parameter is configured to be enabled, only one TRP CRS pattern is applied, and in other cases, two TRP CRS patterns are applied.
Table 16 below shows ServingCellConfig IE including CRS patterns, and table 17 below shows ratematchpattern lte-CRS IEs including at least one parameter of CRS patterns.
TABLE 16
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TABLE 17
As described above, in a single TRP configured UE, only one CRS pattern may be configured per LTE carrier. Thus, in a multi-cell environment, when neighboring LTE cell(s) use a different CRS pattern than the UE's serving cell (LTE-NR co-existence cell), the UE may receive significant interference from the neighboring LTE cell(s). In the above-described problems, interference to the UE may be reduced by proper scheduling of the base station, but scheduling is performed in units of RBs and CRSs are mapped in units of REs, so there is a limit. Hereinafter, the present disclosure proposes a method for minimizing interference from neighboring LTE cell(s) in a multi-cell environment as described above.
"embodiment 1" may refer to an embodiment in which multiple CRS pattern information is configured for neighboring LTE cell(s).
The NR base station may configure CRS pattern information of neighboring LTE cell(s) for the NR UE.
In addition to CRS pattern information of a serving cell (LTE-NR co-existence cell), the NR base station may also configure CRS pattern information of neighboring LTE cell(s) for the NR UE.
The CRS pattern information configured by the NR base station for the NR UE may include CRS pattern information of a serving cell (LTE-NR co-existence cell) and neighboring LTE cell(s).
The CRS pattern information may include an indicator as to whether the corresponding CRS pattern is for a serving cell or a neighboring LTE cell. Alternatively, an indicator may be included that indicates whether the corresponding CRS pattern is for rate matching or interference cancellation.
Configuration information may be sent from the NR base station to the NR UE through higher layer signaling (e.g., RRC signaling).
The NR base station may receive CRS pattern related information (e.g., LTE cell ID, number of CRS transmission ports, v) for each LTE serving cell of the neighboring base station(s) from the neighboring base station(s) shift And/or transmit power). The NR base station may select at least one LTE serving cell of the LTE serving cell(s), and may generate CRS pattern information(s) to be configured in the UE based on CRS pattern-related information of the selected LTE serving cell(s). In selecting at least one LTE serving cell of the LTE serving cell(s), the LTE serving cell(s) having a large transmission power may be preferentially selected. The NR base station may transmit the generated information to the NR UE to configure CRS patterns of LTE cell(s) adjacent to the NR UE.
The NR base station may receive information (e.g., LTE cell ID, number of CRS transmission ports, v) about neighboring LTE serving cell(s) of a UE present in the same frequency band as the serving cell configured in the UE from the UE (e.g., UE supporting both LTE and NR) shift And/or received power). The NR base station may select at least one LTE serving cell of the LTE serving cell(s), and may generate CRS pattern information to be configured in the UE based on CRS pattern-related information of the selected LTE serving cell(s). Procedure in selecting at least one LTE serving cell of LTE serving cell(s)The LTE serving cell(s) with the large received power may be preferentially selected. The NR base station may transmit the generated information to the UE to configure CRS patterns of LTE cell(s) adjacent to the UE.
The NR UE may receive at least one CRS pattern information of a serving cell (LTE-NR co-existence cell) and neighboring LTE cell(s), and may demap PDSCH through rate matching based on the at least one received CRS pattern information, which is a method in which PDSCH is not mapped to specific REs to which CRS(s) are mapped based on CRS pattern information.
The NR UE may receive at least one CRS pattern information of a serving cell (LTE-NR coexisting cell) and neighboring LTE cell(s), and may demap PDSCH through interference cancellation based on the at least one received CRS pattern information, which is a method of mapping PDSCH to specific REs to which CRS(s) are mapped based on the CRS pattern information.
The NR UE may receive at least one CRS pattern information of a serving cell (LTE-NR coexisting cell) and neighboring LTE cell(s), and may demap the received PDSCH in such a manner that rate matching is performed based on the CRS pattern information of the serving cell (LTE-NR coexisting cell), and may demap the received PDSCH in such a manner that interference cancellation is performed based on the CRS pattern information of the neighboring LTE cell(s).
The NR base station may generate CRS pattern information of a serving cell (LTE-NR coexisting cell) and neighboring LTE cell(s) through higher layer signaling (e.g., RRC signaling) and transmit it to the UE, may determine REs to which CRS(s) may be mapped through the CRS pattern information, may determine whether PDSCH is mapped to RE(s), and may map and transmit PDSCH to the UE according to the determination.
Among the RE(s), the NR base station may determine whether the PDSCH is mapped in a rate matching method for the RE(s) to which the CRS used in the LTE carrier of the serving cell (LTE-NR coexisting cell) is mapped, and in an interference cancellation method for the RE(s) to which the CRS used in the neighboring LTE cell(s) is mapped.
According to the disclosure, among RE(s), an NR base station may determine whether PDSCH is mapped in a rate matching method for RE(s) to which CRS used in a serving cell (LTE-NR coexisting cell) is mapped, and RE(s) to which CRS used in a neighboring LTE cell(s) is mapped are used for interference cancellation and may not involve PDSCH mapping. In other words, PDSCH is not mapped to the RE(s) to which CRS used in an LTE carrier of a serving cell (LTE-NR coexisting cell) is mapped, and PDSCH may be mapped to CRS used in neighboring LTE cell(s).
Fig. 7A is a diagram for illustrating the operation of the NR base station according to the embodiment.
Referring to fig. 7A, the NR base station obtains CRS pattern-related information of neighbor serving cell(s) in step 711, generates configuration information based on the obtained information in step 712, and transmits the generated configuration information to the UE in step 713. In step 714, the nr base station performs RE mapping of PDSCH to the UE based on the configuration information and transmits PDSCH in step 715.
Fig. 7B is a diagram for illustrating an operation of the NR UE according to the embodiment.
Referring to fig. 7B, in step 721, the nr UE receives CRS pattern-related configuration information from the base station. Subsequently, the ue receives a PDSCH transmitted from the base station in step 722, and selectively performs an interference cancellation operation based on the received CRS pattern configuration information in step 723. For example, interference cancellation operations may be performed on specific RE(s).
"embodiment 2" may refer to an embodiment that includes an interference cancellation method.
The information about one neighboring LTE cell in CRS pattern information about neighboring LTE cell(s) transmitted by the NR base station to the NR UE of embodiment 1 may include at least a part of the list shown in table 18 below.
TABLE 18
The information about one neighboring LTE cell among CRS pattern information about neighboring LTE cell(s) transmitted by the NR base station to the NR UE of embodiment 1 may Including at least a portion of the list shown in table 19 below. NR UE can obtain v by performing a "mod 6" calculation on the cell ID values of neighboring LTE cells shift (v-Shift) value.
TABLE 19
The information about one neighboring LTE cell in CRS pattern information about neighboring LTE cell(s) transmitted by the NR base station to the NR UE of embodiment 1 may include at least a part of a list shown in table 20 below. The NR UE may assume that the cell ID of the neighboring LTE cell(s) is the same as the cell ID of the NR cell and that the cyclic prefix of the neighboring LTE cell is a normal CP.
TABLE 20
Assuming that the "LTE radio frame boundary" and the "NR radio frame boundary" of the serving cell (LTE-NR coexisting cell) are aligned, the NR UE can determine the "slot index in the LTE radio frame and the OFDM symbol index in the slot". Alternatively, if not aligned, the base station may signal an offset (e.g., a value per NR slot or a value per LTE slot) to the UE, and the UE may determine "slot index in LTE radio frame and OFDM symbol index in slot" based on the signaling. Alternatively, the base station may signal whether or not aligned and, when not aligned, may additionally signal an offset (e.g., a value in NR slots or a value in LTE slots). Alternatively, if the offset is not signaled, the NR UE may operate assuming that the "LTE radio frame boundary" and the "NR radio frame boundary" of the serving cell (LTE-NR coexisting cell) are aligned.
The information about one neighboring LTE cell in CRS pattern information about neighboring LTE cell(s) transmitted by the NR base station to the NR UE of embodiment 1 may include at least a part of the list in table 21.
TABLE 21
As described above, a UE receiving information about neighboring LTE cell(s) may generate sequence(s) of CRS of neighboring LTE cell(s) based on the received information, and may obtain mapping information about time-frequency resources of CRS. At this time, the sequence of CRS may be generated as follows. In this case, m may be an index of RBs to which CRS is mapped.
Reference signal sequenceDefined by equation (3) below.
Wherein n is s Is the slot number within the radio frame and l is the OFDM symbol number within the slot. The pseudo-random sequence c (i) is defined in section 7.2. The pseudo-random sequence generator will be used at the beginning of each OFDM symbolInitialization in which
Based on the CRS sequences obtained in the above-described manner and the time-frequency resource mapping information of the neighboring LTE cell(s), the channel between the neighboring LTE cell(s) and the UE can be estimated from the received CRS signal of the neighboring LTE cell(s). Because the received CRS signal may be mixed with the PDSCH transmission signal of the NR cell due to interference at this time, a process of processing interference through a Successive Interference Cancellation (SIC) process may be required. The SIC process may be configured as follows, or may be otherwise configured.
The reception signal y of the UE may be described as shown in the following equation (4):
y＝h NR-UE x PDSCH +h LTE-UE x CRS +n
... Equation (4)
Wherein:
h NR-UE is a channel between the NR cell and the UE, and is a value obtained in advance by the UE through the PDSCHDM-RS or the like.
x PDSCH Is data transmitted in the NR cell and is a value unknown to the UE;
h LTE-UE is the channel between the neighboring LTE cell and the UE and is a value unknown to the UE;
x CRS is a CRS signal of an adjacent LTE cell, and is a value obtained in advance by the UE; and
n is the noise signal.
At x CRS Is greater than x PDSCH Under the assumption of the received power of (2), the UE may perform the following three (3) steps.
Step 1.H LTE-UE Channel estimation: at this time because of the assumption of hN R-UE x PDSCH Is interference, so that the signal to be estimated, i.e. the SINR of the channel value, isIf this value is not too low, the UE may obtain h LTE-UE Values.
Step 2. H can be subtracted from the received signal y LTE-UE x CRS . The residual signal is
Step 3.X PDSCH And (3) signal decoding: at this time, the SNR of the signal to be decoded isIf this value is not too low, the UE may decode successfully.
Fig. 8 is a diagram for illustrating an operation of an NR UE according to an embodiment.
Referring to fig. 8, in step 801, nr UE receives CRS pattern-related configuration information from a base station. Then, in step 802, the NR UE receives the PDSCH. In step 803, the NR UE generates sequence(s) of CRS(s) based on the CRS pattern-related configuration information obtained in step 801, and determines RE(s) to which CRS(s) are mapped. Further, in step 804, the NR UE performs decoding through the SIC procedure.
"embodiment 3" may refer to an embodiment describing interference cancellation/rate matching operation classification.
Classification by capabilities of the UE will now be described.
UE capability information for interference cancellation as in the first and second embodiments may be defined. The NR UE may receive the UE capability requirement message from the NR base station and respond to the NR base station with a message including UE capability information for interference cancellation. Based on the "UE capability information for interference cancellation" to which the UE responds, the NR base station can configure the UE capable of interference cancellation to perform interference cancellation, and can configure the UE incapable of interference cancellation to perform rate matching.
Fig. 9A is a diagram showing the operation of the NR base station according to the embodiment.
Referring to fig. 9A, the NR base station transmits a UE capability requirement message to the NR UE in step 911 and receives a UE capability message for interference cancellation capability from the UE in step 912. In step 913, the NR base station configures the operation of the UE (interference cancellation and rate matching) based on the UE capability message. Further, the NR base station may generate CRS pattern information of the neighboring serving cell(s) and configure the CRS pattern information in the UE.
Fig. 9B is a diagram for illustrating an operation of the NR UE according to the embodiment.
Referring to fig. 9B, the NR receives a UE capability requirement message from the NR base station in step 921 and transmits a UE capability message for interference cancellation capability to the base station in step 922. Further, in step 923, the nr UE receives operation (interference cancellation, rate matching) configuration information of the UE from the base station and may operate according to the configuration information. Further, the NR UE may receive CRS pattern configuration information of the neighboring serving cell(s) from the base station.
The NR UE may operate in a conventional manner before receiving the information configuration(s) of the neighboring LTE cell(s) of the first and second embodiments. That is, it may be assumed that the NR PDSCH is mapped to REs for transmitting CRSs in neighboring LTE cell(s) to perform operations. The NR UE may receive the information configuration(s) of the neighboring LTE cell(s) of the first and second embodiments. According to this configuration, the NR UE can identify REs transmitting CRSs in the neighboring LTE cell(s) based on the information configuration(s) of the neighboring LTE cell(s), and the NR PDSCH is not mapped to the identified RE(s), and can perform a rate matching operation. The NR UE may receive the "UE capability requirement" message from the NR base station and may respond to the NR base station with UE capability information including interference cancellation for the first and second embodiments. Thereafter, the UE may operate according to the UE capability information. That is, a UE reporting that interference cancellation is not possible may later identify RE(s) for transmitting CRS in neighboring LTE cell(s) based on information configuration of the neighboring LTE cell(s), may assume that NR PDSCH is not mapped to the identified RE(s), and may perform a rate matching operation. On the other hand, a UE reporting that interference cancellation is possible may later identify RE(s) for transmitting CRS in neighboring LTE cell(s) based on information configuration of the neighboring LTE cell(s), may assume that NR PDSCH is mapped to the identified RE(s), and may perform interference cancellation operation according to the first and second embodiments. The table 22 shown below is an example of the UE operation, and the above description is shown.
TABLE 22
The NR UE may operate in a conventional manner before receiving the information configuration(s) of the neighboring LTE cell(s) of the first and second embodiments. That is, it may be assumed that the NR PDSCH is mapped to RE(s) for transmitting CRS in neighboring LTE cell(s) to perform operations. The NR UE may receive the information configuration(s) of the neighboring LTE cell(s) of the first and second embodiments. According to this configuration, the NR UE may identify RE(s) transmitting CRS in the neighboring LTE cell(s) based on information configuration information(s) of the neighboring LTE cell(s), and may assume that the NR PDSCH is not mapped to the identified RE(s), and may perform a rate matching operation. The NR UE may receive the "UE capability requirement" message from the NR base station and may respond to the NR base station with UE capability information including interference cancellation for the first and second embodiments. The NR base station may receive UE capability information for interference cancellation from the UE and may transmit configuration information for subsequent operations (i.e., whether to perform a rate matching operation or an interference cancellation operation) to the UE. The configuration information may be transmitted to the UE through higher layer signaling (RRC), MAC CE, or DCI. Thereafter, the UE may operate according to configuration information of the base station. Table 23 shown below is an example of UE operation, and shows the above description.
TABLE 23
Differences between the indication interference cancellation mode and the rate matching mode will now be described.
The CRS pattern information configured by the NR base station for the NR UE may include CRS pattern information of a serving cell (LTE-NR co-existence cell) and neighboring LTE cell(s). The base station may transmit control signals for at least some operations (e.g., rate matching, interference cancellation, and legacy behavior) corresponding to each CRS pattern information to the UE. The control signal may be transmitted to the UE through higher layer signaling (RRC), MAC CE, or DCI. The UE may perform operations according to a combination of at least one or more control signals.
For RRC-based configuration, the NR UE may receive CRS pattern information and operation indication (interference cancellation indication) information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). The NR UE receiving this information may perform an interference cancellation operation on RE(s) to which CRSs of neighboring LTE cell a are mapped based on the reception control information.
The NR UE may receive CRS pattern information and operation indication (rate matching indication) information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). The NR UE receiving this information may perform a rate matching operation on RE(s) to which CRSs of neighboring LTE cell a are mapped based on the reception control information.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). At this time, the UE may assume that the base station implicitly indicates interference cancellation and may perform interference cancellation operations on RE(s) to which CRSs of neighboring LTE cell a are mapped based on the reception control information.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). At this time, the UE may assume that the base station implicitly indicates interference cancellation and may perform a rate matching operation on RE(s) to which CRSs of neighboring LTE cell a are mapped based on the reception control information.
Unlike the rategypatternlte-CRS IE of table 2, CRS pattern information of neighboring LTE cells or a list of CRS pattern information of neighboring LTE cells may be indicated to the UE by a separate IE that includes at least some of the lists (such as the lists provided by tables 18-21).
Fig. 10A is a diagram for illustrating an operation of an NR UE according to an embodiment.
Referring to fig. 10A, in step 1011, the NR UE receives CRS pattern information of neighbor cell(s) from a base station through an RRC message. The operation indication (interference cancellation or rate matching) information may be additionally included in the RRC configuration message. Alternatively, the operation indication (interference cancellation or rate matching) information may be included in a separate RRC configuration message. Additionally, operations in the case of receiving CRS pattern information of neighboring cell(s) may be implicitly provided. Further, the operation in the case of receiving CRS pattern information of the neighboring cell(s) may be implicitly provided according to the capability of the UE. In step 1012, the ue performs interference cancellation or rate matching operations according to the received RRC configuration information.
The configuration based on rrc+l1/L2 will now be described.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). Additionally, the NR UE may receive operation indication (interference cancellation indication) information from the NR base station through, for example, MAC CE or DCI. The NR UE receiving this information may perform an interference cancellation operation on RE(s) to which CRSs of neighboring LTE cell a are mapped based on the reception control information. The UE may operate under the assumption of rate matching before receiving the operation instruction (interference cancellation instruction) information. The operation indication information may be newly defined in the MAC CE or in the DCI format. When the operation indication (interference cancellation indication) information is defined in the DCI format, the size of the field containing the operation indication (interference cancellation indication) information may be based on the number of CRS pattern information of neighboring LTE cells configured through higher layer signaling. That is, when information of two neighboring cells is received, it may be 2 bits, and when information of three neighboring cells is received, it may be 3 bits. Thus, the base station may instruct the UE to independently process each of the RE(s) to which the CRS of the neighboring LTE cell is mapped.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). Additionally, the NR UE may receive operation indication (rate matching indication) information from the NR base station through, for example, MAC CE or DCI. The NR UE receiving this information may perform a rate matching operation on RE(s) to which CRSs of neighboring LTE cell a are mapped based on the reception control information. The UE may operate under the assumption of rate matching before receiving the operation instruction (rate matching instruction) information. The operation indication information may be newly defined in the MAC CE or in the DCI format. When the operation indication (rate matching indication) information is newly defined in the DCI format, the size of the field containing the operation indication (rate matching indication) information may be based on the number of CRS pattern information of neighboring LTE cells configured through higher layer signaling. That is, when information of two neighboring cells is received, it may be 2 bits, and when information of three neighboring cells is received, it may be 3 bits. Thus, the base station may instruct the UE to independently process each of the RE(s) to which the CRS of the neighboring LTE cell is mapped.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). Additionally, the NR UE may receive operation indication (interference cancellation and rate matching) information (1 bit) from the NR base station through, for example, MAC CE or DCI. The NR UE receiving this information may perform an interference cancellation or rate matching operation on the RE(s) to which the CRS of the neighboring LTE cell a is mapped based on the reception control information. The UE may operate under the assumption of rate matching before receiving the operation instruction (rate matching instruction) information. The operation indication information may be newly defined in the MAC CE or in the DCI format. When the operation indication (interference cancellation and rate matching) information is defined in the DCI format, the size of the field containing the operation indication (interference cancellation and rate matching) information may be based on the number of CRS pattern information of neighboring LTE cells configured through higher layer signaling. That is, when information of two neighboring cells is received, it may be 2 bits, and when information of three neighboring cells is received, it may be 3 bits. Thus, the base station may instruct the UE to independently process each of the RE(s) to which the CRS of the neighboring LTE cell is mapped.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). Additionally, the NR UE may receive operation indication (interference cancellation and rate matching) information from the NR base station through DCI. The operation indication information may be indicated by a value of at least some of the field(s) already existing in the DCI format. For example, the values of the modulation and coding scheme fields in the DCI format may be used. Assuming that the value of this field ranges from 0 to 31, when a value lower than a specific value is indicated to the UE through the DCI format, the UE may understand it as an indication of interference cancellation and operate, and when a value higher than or equal to the specific value is indicated to the UE through the DCI format, the UE may understand it as an indication of rate matching and operate. In contrast, when a value lower than a specific value is indicated to the UE through the DCI format, the UE may understand it as an indication of rate matching and operate, and when a value higher than or equal to the specific value is indicated to the UE through the DCI format, the UE may understand it as an indication of interference cancellation and operate. At this point, the NR UE may process all configured REs to which CRSs of all neighboring LTE cells are mapped in the same manner (i.e., all interference cancellation or all rate matching). The specific value may be predefined by an NR standard document (i.e., pre-stored in the UE) or transmitted to the UE through control information (e.g., RRC settings) configured for the UE by the NR base station.
The NR UE may receive CRS pattern information of neighboring LTE cell a from the NR base station through higher layer signaling (e.g., RRC signaling). Additionally, the NR UE may receive operation indication (interference cancellation and rate matching) information from the NR base station through DCI. The operation indication information may be indicated by a value of at least some of the field(s) already existing in the DCI format.
For example, the value of the DMRS sequence initialization field in the DCI format may be used. When 0 is indicated as a field value, the UE may understand and operate to configure a PDSCH DMRS sequence initialization value corresponding to the field value and also indicate rate matching for CRS. Meanwhile, when 1 is indicated as a field value, the UE may understand and operate to configure a PDSCH DMRS sequence initialization value corresponding to the field value, and also indicate interference control for CRS (or vice versa). At this point, the NR UE may process all configured REs to which CRSs of all neighboring LTE cells are mapped in the same manner (i.e., all interference cancellation or all rate matching). The mapping between DMRS sequence initialization field values and rate matching or interference control operations for CRS may be predefined by NR standard documents (i.e., pre-stored in the UE) or transmitted to the UE through control information (e.g., RRC settings) configured for the UE by the NR base station.
Fig. 10B is a diagram for illustrating an operation of the NR UE according to the embodiment.
Referring to fig. 10B, in step 1021, the NR UE receives CRS pattern information of neighbor cell(s) from the base station through an RRC message. In step 1022, the nr UE receives DCI from the base station and performs an interference cancellation or rate matching operation according to operation indication information included in the DCI. The operation indication information may also be received through the MAC CE instead of the DCI.
A number of TRP "scenarios will now be described.
An NR UE receiving data from a plurality of TRPs may determine whether to perform interference cancellation or rate matching for each TRP according to the type of TRP. For example, if each TRP of the plurality of TRPs is directed to a base station of an LTE-NR co-existence cell, CRS rate matching may be required because the interference signal strength received from the TRP closest to the UE is very large compared to the NR signal strength. On the other hand, CRS interference cancellation operations may be appropriate because the ratio of NR signal strength to CRS signal strength from the remaining TRPs may be relatively small. Or vice versa, it may be appropriate to perform CRS interference cancellation from the closest TRP and CRS rate matching operations from the remaining TRPs. Thus, NR UEs may remove CRS from a particular TRP by performing an interference cancellation operation, and CRS from another TRP may perform a rate matching operation.
At this time, the TRP performing CRS interference cancellation and CRS rate matching operations may be predefined (i.e., pre-stored in the UE) by the NR standard document, or may be delivered to the UE by control information (e.g., RRC settings) configured for the UE by the NR base station. The TRP defined above or configured by control information may be represented as an index value configured for each CORESET, e.g., coresetpoinolindex value, physical Cell ID (PCID), and/or SSB index. The CRS rate matching operation may be applied to CORESET configured with coresetpoolndex=0, and the CRS interference cancellation operation may be applied to CORESET configured with coresetpoolndex=1.
Fig. 11 is a diagram for illustrating an operation of an NR UE according to an embodiment.
Referring to fig. 11, in step 1101, the nr UE receives configuration information of each TRP from the base station. Then, in step 1102, the ue receives PDSCH from the plurality of TRPs. In step 1103, the UE performs an interference cancellation or rate matching operation on each TRP of each PDSCH received based on the configuration information received from the base station.
Operation in MBSFN will now be described.
The NR UE may receive the MBSFN-subframe configlist from the NR base station through the ratematchpattern LTE-CRS IE of table 2, and may identify a slot corresponding to (overlapping) an MBSFN subframe in LTE among slots of a serving cell (LTE-NR coexisting cell). In the identified time slots, the interference cancellation according to the above-described embodiments may not be performed. In the identified time slot(s), a rate matching operation may be performed. Alternatively, rate matching may be performed only on CRS RE(s) present in MBSFN subframes.
The NR UE may receive "MBSFN-subframe configlist" of neighboring LTE cell(s) from the NR base station and may identify a slot corresponding to (overlapping) MBSFN subframes in LTE among slots of a serving cell (LTE-NR coexisting cell). In the identified time slots, interference cancellation may not be performed. In the identified time slot(s), a rate matching operation may be performed. Alternatively, rate matching may be performed only on CRS RE(s) present in MBSFN subframes.
"embodiment 4" may refer to an embodiment in which NR PDSCH mapping is performed only at CRS RE(s) of some slots.
Mapping of PDSCH to CRS RE(s) of LTE of NR in the above embodiments may be applied to some of the NR slots. The NR PDSCH may not be mapped to CRS RE(s) of LTE included in the remaining slots other than the slots of some applications.
The NR base station may deliver information (e.g., at least one of a plurality of defined slot patterns and/or a list of slots) to the NR UE regarding the slots of the mapping of the NR PDSCH to the LTE CRS RE(s). Based on this information, the UE may perform an interference cancellation operation according to the above-described embodiments in the slots where the NR PDSCH is mapped to LTE CRS RE(s), and perform a rate matching operation in the remaining slots. Further, in the remaining slots, the NR UE may receive LTE CRS(s) and use LTE CRS(s) to estimate H of equation (2) LTE-UE Information.
The LTE base station may deliver information (e.g., at least one of a plurality of defined slot patterns and/or a list of slots) to the NR UE regarding the slots of the mapping of the NR PDSCH to the LTE CRS RE(s). Based on this information, the UE may discard CRS RE(s) received in the slot where the mapping of NR PDSCH to LTE CRS RE(s) is applied, without being used for channel estimation.
"embodiment 5" may refer to embodiments that incorporate some or all of the foregoing embodiments.
To perform the above-described embodiments of the present disclosure, the transceivers, memories, and processors of the UE and the base station, respectively, are shown in fig. 12 and 13. In the above-described embodiments, a method for configuring CRS pattern information for neighboring LTE cell(s), a method for configuring operation (interference cancellation or rate matching), a method for indicating operation, and a method for exchanging UE capability information are shown. For this, the transceivers, memories and processors of the base station and UE, respectively, must operate in accordance with the above-described embodiments.
Fig. 12 shows a structure of a UE according to an embodiment.
Referring to fig. 12, the ue includes a transceiver 1201, a memory 1202, and a processor 1203. However, components of the UE are not limited to the above examples. For example, the UE may include more or fewer components than those described above. Further, the transceiver 1201, the memory 1202, and the processor 1203 may be implemented in the form of a single chip.
Transceiver 1201 may transmit signals to/receive signals from a base station. The signals may include control information and data. To this end, the transceiver 1201 may include a Radio Frequency (RF) transmitter for up-converting and amplifying the frequency of a transmission signal, and an RF receiver for low noise amplifying and down-converting a reception signal. Further, the transceiver 1201 may receive signals through a wireless channel, output signals to the processor 1203, and transmit signals output from the processor 1203 through a wireless channel.
The memory 1202 may store programs and data required for UE operation. Further, the memory 1202 may store control information or data included in signals transmitted and received by the UE. The memory 1202 may be configured as a storage medium such as a read-only memory (ROM), a random-access memory (RAM), a hard disk, a Compact Disk (CD) -ROM, and a Digital Versatile Disk (DVD), or a combination of storage media. Further, the memory 1202 may be composed of a plurality of memories, and may store a program for removing and decoding interference from a certain or more REs in the PDSCH of the UE.
The processor 1203 may control a series of processes by which the UE may operate in accordance with the above described embodiments. For example, the processor 1203 may control decoding and removing interference from some or more res in PDSCH.
In particular, the processor 1203 may receive CRS pattern configuration related information of neighboring LTE cell(s) from the base station, and may control each configuration of the UE having an interference cancellation operation or a rate matching operation in a certain one or more REs in the PDSCH received from the base station based on the CSR pattern configuration related information of neighboring LTE cell(s) from the base station.
In particular, the processor 1203 may receive CRS pattern configuration related information of neighboring LTE cell(s) from the base station, and may control each configuration of UEs having interference cancellation operation or rate matching operation in a certain or more REs in PDSCH received from the base station based on the CSR pattern configuration related information of neighboring LTE cell(s) and operation instruction information delivered through higher layer signaling or lower layer signaling (DCI or MAC CE) from the base station.
Further, the processor 1203 may include a plurality of processors, and by executing programs stored in the memory 1202, a method of removing and decoding interference from a certain or more REs in the PDSCH may be performed.
Fig. 13 shows a structure of a base station according to an embodiment.
Referring to fig. 13, the base station includes a transceiver 1301, a memory 1302, and a processor 1303. However, components of the UE are not limited to the above examples. For example, a base station may include more or fewer components than those described above. Further, the transceiver 1301, the memory 1302, and the processor 1303 may be implemented in the form of a single chip.
The transceiver 1301 may transmit/receive signals to/from a UE. The signals may include control information and data. To this end, the transceiver 1301 may include an RF transmitter for up-converting and amplifying the frequency of a transmission signal, and an RF receiver for low noise amplifying and down-converting a reception signal. Further, the transceiver 1301 may receive a signal through a wireless channel, output the signal to the processor 1303, and transmit the signal output from the processor 1303 through the wireless channel.
The memory 1302 may store programs and data required for operation of the base station. Further, the memory 1302 may store control information or data included in signals transmitted and received by the base station. The memory 1302 may be configured as a storage medium (such as ROM, RAM, hard disk, CD-ROM, and DVD) or a combination of storage media. Further, the memory 1302 may be composed of a plurality of memories. The memory 1302 may store a program for generating CRS pattern configuration-related information of neighboring LTE cell(s) of a base station and transmitting the information to a UE. Alternatively, the memory 1302 may store a program for generating CRS pattern configuration-related information of neighboring LTE cell(s) of the base station and transmitting the information to the UE. Additionally, the memory 1302 may store a program for generating and transmitting a downlink control channel or MAC CE containing information indicative of an interference cancellation operation or a rate matching operation. The memory 1302 may additionally store data mapping determination programs for specific RE(s) in the PDSCH.
The processor 1303 may control a series of processes by which the base station may operate according to the above-described embodiments of the present disclosure. For example, the processor 1303 may control each configuration of the base station to generate and transmit CRS pattern configuration information of neighboring LTE cell(s), generate and transmit information indicating an interference cancellation operation or a rate matching operation, and determine a data mapping to specific RE(s) in the PDSCH based on the configuration information and the operation indication information.
Further, the processor 1303 may include a plurality of processors, and by executing programs stored in the memory 1302, a method of generating and transmitting CRS pattern configuration-related information of neighboring LTE cell(s), a method of indicating an interference cancellation operation or a rate matching operation, and a method of mapping symbols to specific RE(s) in the PDSCH based on the configuration information and the operation indication information may be performed.
The methods described in the claims or specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.
When the methods are implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within the electronic device. The at least one program may include instructions that cause an electronic device to perform a method according to various embodiments of the present disclosure defined by the appended claims and/or disclosed herein.
Programs (software modules or software) may be stored in non-volatile memory (including RAM and flash memory, ROM, electrically Erasable Programmable ROM (EEPROM), magnetic disk storage, CD-ROM, DVD, other types of optical storage devices, or magnetic cassettes). Alternatively, any combination of some or all of the non-volatile memory may form the memory in which the program is stored. Further, a plurality of such memories may be included in the electronic device.
Further, the program may be stored in an attachable storage device that may access the electronic device through a communication network, such as the internet, an intranet, a Local Area Network (LAN), a wide area network (WLAN), a Storage Area Network (SAN), or a combination thereof. Such a storage device may access the electronic device through an external port. In addition, a separate storage device on the communication network may access the portable electronic device.
In the above detailed embodiments of the present disclosure, elements included in the present disclosure are expressed in singular or plural according to the presented detailed embodiments. However, for convenience of description, the singular or plural forms are appropriately selected as the presented case, and the present disclosure is not limited to the elements expressed in the singular or plural. Accordingly, an element expressed in a plurality of numbers may include a single element, or an element expressed in a singular may include a plurality of elements.
The embodiments of the present disclosure described and illustrated in the specification and drawings are merely specific examples presented to easily explain the technical content of the present disclosure and to aid understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is apparent to those skilled in the art that other modifications based on the technical ideas of the present disclosure can be implemented. Further, the respective embodiments described above may be used in combination as required. Further, the embodiments of the present disclosure may be applied to other communication systems, and other modifications based on the technical ideas of the embodiments may also be implemented. For example, embodiments may be applied to LTE, 5G, and NR systems.
While the present disclosure has been particularly shown and described with reference to certain embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims and their equivalents.
Claims (14)
1. A method performed by a terminal in a communication system, the method comprising:
receiving configuration information associated with a cell-specific reference signal, CRS, pattern of a cell from a base station via higher layer signaling;
Identifying resource elements, REs, of CRS based on the configuration information;
determining whether a physical downlink shared channel, PDSCH, is received on REs of the CRS;
the PDSCH is received from the base station based on the determination,
wherein the PDSCH is received by performing interference cancellation in a case where the PDSCH is received on REs of the CRS.
2. The method of claim 1, wherein the PDSCH is received by performing rate matching if the PDSCH is not received on REs of CRS.
3. The method of claim 1, wherein receiving the PDSCH further comprises:
generating a CRS sequence based on the configuration information;
estimating a channel with the cell based on the CRS sequence and a received signal; and
the PDSCH is received from the base station on REs of the CRS by cancelling the CRS from the received signal based on the CRS sequence and a channel with the cell.
4. The method of claim 1, wherein determining whether the PDSCH is received on REs of the CRS is based on at least one of:
capability information sent to the base station; or alternatively
And receiving configuration from the base station according to the capability information.
5. The method of claim 1, wherein determining whether the PDSCH is received on REs of the CRS is based on at least one of radio resource control, RRC, signaling, medium access control, MAC, control element, CE, or downlink control information, DCI.
6. The method of claim 1, wherein determining whether the PDSCH is received on REs of the CRS is based on at least one of:
transmitting and receiving points TRP transmitting the PDSCH;
multimedia broadcast single frequency network MBSFN subframe configuration; or alternatively
A configuration defining whether the PDSCH is transmitted on REs of the CRS in a slot.
7. A terminal in a communication system, the terminal comprising:
a transceiver; and
a controller configured to:
receiving configuration information associated with a cell-specific reference signal, CRS, pattern of a cell from a base station via higher layer signaling;
identifying resource elements, REs, of CRS based on the configuration information;
determining whether a physical downlink shared channel, PDSCH, is received on REs of the CRS;
the PDSCH is received from the base station based on the determination,
wherein the PDSCH is received by performing interference cancellation in a case where the PDSCH is received on REs of the CRS.
8. The terminal of claim 7, wherein the PDSCH is received by performing rate matching if the PDSCH is not received on REs of the CRS.
9. The terminal of claim 7, wherein receiving PDSCH further comprises:
generating a CRS sequence based on the configuration information;
estimating a channel with the cell based on the CRS sequence and a received signal; and
PDSCH is received from the base station on REs of the CRS by cancelling CRS from the received signal based on the CRS sequence and a channel with the cell.
10. The terminal of claim 7, wherein determining whether the PDSCH is received on REs of the CRS is based on at least one of:
capability information sent to the base station; or alternatively
And receiving configuration from the base station according to the capability information.
11. The terminal of claim 7, wherein determining whether the PDSCH is received on REs of the CRS is based on at least one of radio resource control, RRC, signaling, medium access control, MAC, control element, CE, or downlink control information, DCI.
12. The terminal of claim 7, wherein determining whether the PDSCH is received on REs of CRS is based on at least one of:
Transmitting and receiving points TRP transmitting the PDSCH;
multimedia broadcast single frequency network MBSFN subframe configuration; or alternatively
A configuration defining whether PDSCH is transmitted on REs of the CRS in a slot.
13. A method performed by a base station in a communication system, the method comprising:
transmitting configuration information associated with a cell-specific reference signal, CRS, pattern of a cell to a terminal via higher layer signaling;
identifying resource elements, REs, of CRS based on the configuration information;
determining whether to transmit a physical downlink shared channel, PDSCH, on REs of the CRS; and
and transmitting the PDSCH to the terminal based on the determination.
14. A base station in a communication system, the base station comprising:
a transceiver; and
a controller configured to:
transmitting configuration information associated with a cell-specific reference signal, CRS, pattern of a cell to a terminal via higher layer signaling;
identifying resource elements, REs, of CRS based on the configuration information;
determining whether to transmit a physical downlink shared channel, PDSCH, on REs of the CRS; and
and transmitting the PDSCH to the terminal based on the determination.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2020-0169857 | 2020-12-07 | ||
| KR10-2020-0182446 | 2020-12-23 | ||
| KR1020200182446A KR20220080654A (en) | 2020-12-07 | 2020-12-23 | Apparatus and method for inter-cell interference management in wireless communication systems |
| PCT/KR2021/018422 WO2022124750A1 (en) | 2020-12-07 | 2021-12-07 | Apparatus and method for inter-cell interference control for wireless communication system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116584055A true CN116584055A (en) | 2023-08-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180081789.6A Pending CN116584055A (en) | 2020-12-07 | 2021-12-07 | Apparatus and method for inter-cell interference control in a wireless communication system |
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| Country | Link |
|---|---|
| CN (1) | CN116584055A (en) |
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2021
- 2021-12-07 CN CN202180081789.6A patent/CN116584055A/en active Pending
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