CN118202579A

CN118202579A - Base station performing link adaptation of coordinated multipoint system and operation thereof

Info

Publication number: CN118202579A
Application number: CN202280073280.1A
Authority: CN
Inventors: 李德熙; 李明焕
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2021-11-01
Filing date: 2022-11-01
Publication date: 2024-06-14

Abstract

A method for operating a first Base Station (BS) performing wireless communication with a User Equipment (UE) may include: receiving a message from a second base station, the message including at least one piece of information associated with operation of coordinated multipoint (CoMP) operations for user terminals connected to the first base station; if the received message includes information informing of the start of the operation of CoMP operation, the CoMP operation is operated at a point of time indicated based on at least a part of at least one piece of information included in the received message; raising the MCS level for a first period of time; if the MCS level reaches a preset first level based on the rise during the first period, maintaining operation of the CoMP operation for a second period; ending the CoMP operation at a point in time indicated based on at least a portion of at least one piece of information included in the received message if the received information includes information informing of the end of the operation of the CoMP operation; and decreasing the MCS level for a third time period.

Description

Base station performing link adaptation of coordinated multipoint system and operation thereof

Technical Field

Various example embodiments relate to a Base Station (BS) for performing link adaptation in a coordinated multipoint (CoMP) system and/or a method of operating the BS.

Background

As Long Term Evolution (LTE), fifth generation (5G), and sixth generation (6G) evolves, interference and noise increasingly affect channels. Link adaptation is a technique to adaptively overcome channel problems based on radio link conditions. Because propagation conditions between a Base Station (BS) and a roaming or cell edge wireless terminal change continuously over time, link adaptation is required to transmit data without errors by applying appropriate parameters according to the state of the wireless link.

The link adaptation algorithm provides a data rate suitable for a channel environment by dynamically adjusting a Modulation and Coding Scheme (MCS) level and/or a rate-related parameter according to the wireless channel environment. Parameters are defined for link adaptation operations. In the fourth generation (4G) LTE/5G new wireless (NR), a link adaptation algorithm based on hybrid automatic repeat request (HARQ) Acknowledgement (ACK)/Negative ACK (NACK) feedback and a link adaptation algorithm based on Channel State Information (CSI) feedback are generally applied. These algorithmic approaches may be used continuously in HARQ-based communication systems.

In link adaptation, the network transceiver may select a set of modulation schemes and coding schemes defined based on instantaneous estimates of the quality of the downlink channel to each wireless terminal (e.g., user Equipment (UE)). The channel information is typically reported by the UE and may include a signal to interference and noise ratio (SINR) measured or estimated by the UE.

Since LTE release 8/9, active research has been conducted on broadband wireless communication systems. In a broadband wireless communication system, a modulation scheme for transmitting data and a coding rate of an error correction code are determined to be suitable for a channel environment before transmitting the data. The MCS level for Downlink (DL) transmission or Uplink (UL) transmission may be implemented in various ways according to methods in a broadband wireless communication system, generally in the following manner.

In the case of DL, upon receiving CSI and a response signal for DL data (i.e., an ACK/NACK signal from the UE), the BS determines a channel state of the UE based on the CSI and ACK/NACK signals. The BS detects an MCS level corresponding to the determined channel state with reference to an MCS decision table including MCS level information for each predetermined channel state. The BS then transmits DL data to the UE using the detected MCS level.

In the case of UL, the BS typically receives UL channel state (sounding reference signal (SRS)) information from the UE and measures SRS-based SINR according to average thermal interference (IoT) of a Physical Uplink Shared Channel (PUSCH) for each cell. Then, the BS receives a response signal to the DL data, i.e., an ACK/NACK signal, and determines a channel state of the UE based on CSI (SINR based on SRS) and the ACK/NACK signal. In addition, the BS detects an MCS level corresponding to the determined channel state with reference to an MCS decision table including MCS level information for each predetermined channel state. The BS may then transmit DL data to the UE using the detected MCS level.

In coordinated multipoint (CoMP) standards, coMP transmission/reception or multi-cell multiple-input multiple-output (MIMO) has been introduced, wherein neighboring or adjacent cells cooperate taking into account the instantaneous channel and traffic conditions of UEs at the cell edge. CoMP types include Joint Transmission (JT), coordinated Scheduling (CS), coordinated Beamforming (CB), beam nulling, minimum Mean Square Error (MMSE), and Dynamic Point Selection (DPS) for DL CoMP, and Joint Reception (JR), CS, and CB for UL CoMP. According to DL CS/CB CoMP, when a plurality of BSs communicate with UEs through antenna beamforming, each UE may select antenna beamforming of each BS to increase the capacity of cell-edge UEs. Each UE selects antenna beamforming for each BS such that signals from the serving BS are maximized or increased and interference signals from neighboring or neighbor BSs are minimized or reduced. The CS/CB CoMP cooperative BS transmits data only to its UEs, and not to UEs of neighboring cooperative cells. CoMP techniques may have problems in that the amount of information that needs to be transmitted to the backhaul for BS cooperation is large, and scheduling for resource allocation and CoMP signal processing calculation is complex. However, coMP has attracted attention as a cell co-scheduling technique with reduced implementation complexity in view of its benefits of improved cell edge and cell average capacity, as compared to inter-cell interference coordination (ICIC) techniques.

Disclosure of Invention

Technical problem

The Base Station (BS) determines a Modulation and Coding Scheme (MCS) level based on only interference information measured on a cell basis, uplink (UL) pilot strength information received from the UE, and Acknowledgement (ACK) information regardless of a channel environment of the User Equipment (UE). Whether or not coordinated multipoint (CoMP) operation is performed within the CoMP measurement set, the BS increases or decreases the MCS level with respect to the number of hybrid automatic repeat request (HARQ) feedback receptions. However, when the rate of rise (or rise rate) of the MCS level is relatively low, it is likely that a relatively low MCS level is used even when the CoMP function is being performed. When the MCS level is low for data transmission, the data rate may be low regardless of a high signal to interference and noise ratio (SINR) of a wireless channel between the UE and the BS. Further, when SINR of the wireless channel is low, even if the MCS level is raised in data transmission, the data rate may be low and the data transmission may fail. Thus, since the MCS level does not rise at a relatively high speed (or rate) regardless of whether the CoMP function is running, the data rate is likely to rise at a relatively low speed (or rate).

The BS and the operation method thereof according to various example embodiments may raise the MCS level at a relatively high speed (or rate) based on the identification of when to perform the CoMP function. Thus, an appropriate MCS level suitable for the SINR case of the wireless channel can be used, and the data rate can also be increased.

Technical proposal

Certain example embodiments may rapidly raise or lower a Modulation and Coding Scheme (MCS) level in consideration of performing coordinated multipoint (CoMP) operations and link adaptation algorithms for a cell edge User Equipment (UE) to which CoMP techniques are applied.

According to various example embodiments, a method of operating a first BS for performing wireless communication with a UE may include: receiving a message from a second BS connected to the first BS, the message including at least one piece of information associated with whether to perform CoMP operation for a UE connected to the first BS; when the received message includes information indicating the start of the CoMP operation, performing the CoMP operation, raising an MCS level during a first period, and maintaining the performed CoMP operation during a second period after the MCS level reaches a specified first level based on the raising during the first period, at a timing indicated based on at least a portion of at least one piece of information included in the received message; and terminating the CoMP operation at a timing indicated based on at least a portion of at least one piece of information included in the received message and reducing the MCS level during the third period when the received message includes information indicating termination of the CoMP operation.

According to various example embodiments, a first BS for performing wireless communication with a UE includes: a transceiver; and at least one processor including processing circuitry. The at least one processor may be configured to: receiving, by the transceiver, a message from a second BS connected to the first BS, the message including at least one piece of information associated with whether to perform CoMP operations for a UE connected to the first BS; when the received message includes information indicating the start of the CoMP operation, performing the CoMP operation, raising an MCS level during a first period, and maintaining the performed CoMP operation during a second period after the MCS level reaches a specified first level based on the raising during the first period, at a timing indicated based on at least a portion of at least one piece of information included in the received message; and terminating the CoMP operation at a timing indicated based on at least a portion of at least one piece of information included in the received message and reducing the MCS level during the third period when the received message includes information indicating termination of the CoMP operation.

Advantageous effects

According to various example embodiments, a method and/or apparatus for adaptively and rapidly increasing/decreasing a Modulation and Coding Scheme (MCS) level according to a real-time channel state may be provided in a Base Station (BS) for performing coordinated multipoint (CoMP) operation in a wireless communication system. As the MCS level is rapidly increased and then maintained to converge to a certain level during the CoMP operation is maintained, the CoMP operation may be optimally applied to maximize or increase diversity gain. Further, cyclic Redundancy Check (CRC) failure probability can be reduced by rapidly lowering the MCS level, and throughput loss caused by hybrid automatic repeat request (HARQ) retransmission can be minimized or reduced.

According to various example embodiments, an optimal MCS level may be reached in a short time in consideration of a signal to interference and noise ratio (SINR) increment according to whether CoMP operation is performed.

Drawings

The foregoing and other aspects, features, and advantages of certain example embodiments of the disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

fig. 1a is a block diagram illustrating a Radio Access Network (RAN) and a Core Network (CN) according to various example embodiments.

Fig. 1B is a block diagram illustrating a hardware configuration of a next generation node B (gNB) according to various example embodiments.

Fig. 1c is a diagram showing a basic structure of a time-frequency region as a radio resource region for carrying data or control channels in a fifth generation (5G) system.

Fig. 1d is a diagram illustrating a slot structure considered in a 5G system.

Fig. 1e is a diagram illustrating an exemplary bandwidth part (BWP) configuration in a 5G system.

Fig. 2 is a diagram illustrating coordinated multipoint (CoMP) operation for User Equipment (UE) at the cell edge, according to various example embodiments.

Fig. 3 is a diagram illustrating Modulation and Coding Scheme (MCS) levels according to an increase in signal to interference and noise ratio (SINR) according to various example embodiments.

Fig. 4a is a diagram showing a variation trend of execution of CoMP-based operation according to SINR and MCS levels of a comparative example for comparison with various example embodiments.

Fig. 4b is a diagram showing an increase in MCS level according to hybrid automatic repeat request (HARQ) Acknowledgement (ACK) retransmission according to a comparative example.

Fig. 4c is a graph showing a trend of variation in SINR and MCS level based on execution of CoMP operation according to the comparative example.

Fig. 5a is a diagram illustrating a trend of variation in SINR and MCS level based on execution of CoMP operation according to an example embodiment.

Fig. 5b is an enlarged view illustrating a rising period of the MCS level of fig. 5 a.

Fig. 5c is a flowchart illustrating an operation of adjusting an MCS level according to whether CoMP operation is applied together with link adaptation algorithm operation.

Fig. 6a is a diagram illustrating the operation of a serving gNB and a helping gNB according to an example embodiment.

Fig. 6b is a flowchart illustrating operation from the perspective of a service gNB according to an example embodiment.

Fig. 7a is a diagram illustrating an increase in MCS level according to the HARQ ACK reception times according to an example embodiment.

Fig. 7b is a diagram illustrating a case where an MCS level is increased by 1 or more according to an example embodiment.

Fig. 7c is a flowchart illustrating an operation of rapidly increasing an MCS level according to an example embodiment.

Detailed Description

In addition to the voice-centric services of the initial development phase, wireless communication systems have evolved towards broadband wireless communication systems that provide high-speed and high-quality packet data services. A Long Term Evolution (LTE) system, which is a representative example of a broadband wireless communication system, employs Orthogonal Frequency Division Multiplexing (OFDM) for Downlink (DL) and single carrier frequency division multiple access (SC-FDMA) for Uplink (UL). UL refers to a radio link over which a User Equipment (UE) or a Mobile Station (MS) transmits data or control signals to an evolved node B (eNode B) or a Base Station (BS). DL refers to a radio link over which a BS transmits data or control signals to a UE. In the multiple access scheme as described above, time-frequency resources used to carry data or control information for each user are allocated and operated without overlapping each other (i.e., in orthogonality) to distinguish the data or control information.

A fifth generation (5G) communication system, which is a next generation communication system after LTE and currently provides communication services, can support services that satisfy various requirements of users and service providers. Services considered for 5G communication systems include enhanced mobile broadband (eMBB), large-scale machine type communication (mMTC), ultra-reliable low-latency communication (URLLC), and so forth.

EMBB aims to provide higher data rates than supported by legacy LTE, LTE-advanced (LTE-a) or LTE-Pro. For example, eMBB should be able to provide a peak data rate of 20Gbps on DL and a peak data rate of 10Gbps on UL from the perspective of one BS in a 5G communication system. In addition, the 5G communication system should provide the UE with an increased user perceived data rate while providing a peak data rate. To meet these requirements, various improved transmission and reception techniques including advanced Multiple Input Multiple Output (MIMO) techniques are necessary. Signals are transmitted in a transmission bandwidth up to 20MHz in a 2GHz band used in LTE, however, in order to satisfy a required data transmission rate in a 5G communication system, a frequency bandwidth wider than 20MHz is used in a band of 3 to 6GHz or higher.

Further, mMTC is considered in order to support application services such as internet of things (IoT) in a 5G communication system. In order to efficiently provide IoT, mctc requires large-scale UE access support within a cell, improved UE coverage, increased battery life, and reduced UE cost. Since IoT provides communication functionality by attaching to various sensors and devices, ioT should be able to support a large number of UEs (e.g., 1000000 UEs/km 2) within a cell. Because the mMTC-capable UE is most likely located in a shadow area not covered by a cell (such as a basement of a building), it may require a wide coverage range compared to other services provided by the 5G communication system in view of the nature of the services. mMTC UE should be inexpensive and require very long battery life, such as 10 to 15 years, due to the difficulty of frequent battery replacement.

Finally URLLC is a cellular-based wireless communication service for specific (mission critical) purposes. For example, services for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote health care, emergency alerts, etc. may be considered. Therefore URLLC communications should provide very low latency and very high reliability. For example, a service supporting URLLC should meet an air interface delay of less than 0.5 ms and require a packet error rate of 10 ^-5 or less. Thus, a 5G system should provide a smaller Transmission Time Interval (TTI) for services supporting URLLC than for other services, and may require a design that allocates wide resources in the frequency band to ensure reliability of the communication link.

Three 5G services, namely, eMBB, URLLC, and mMTC, can be multiplexed and transmitted in one system. In this case, in order to meet different requirements of each service, different transmission/reception techniques and transmission/reception parameters may be used between the services. The 5G is not limited to the above three services.

For ease of description, some terms and names defined in the third generation partnership project (3 GPP) standard (5G, new wireless (NR), LTE or standards of similar systems) may be used. However, the present disclosure is not limited by these terms and names, and may be equally applicable to systems conforming to other standards. Further, for convenience of description, terms for identifying an access node, terms for referring to network entities, terms for referring to messages, terms for referring to interfaces between network entities, terms for referring to various types of identification information, and the like, as used in the following description, are given by way of example. Thus, terms as used in the present disclosure do not limit the present disclosure, and may be replaced with other terms referring to objects having equivalent technical meanings.

In describing embodiments, descriptions of technical contents that are well known in the technical field of the present disclosure and are not directly related to the present disclosure will be avoided so as not to obscure the subject matter of the present disclosure.

For the same reason, in the drawings, some components are exaggerated, omitted, or schematically shown. In addition, the size of each component does not fully reflect the actual size. Like reference numerals designate identical or corresponding components throughout each of the several views.

The advantages and features of the present disclosure and methods of accomplishing the same will become apparent from the reference to the following detailed description of embodiments taken in conjunction with the accompanying drawings. However, the present disclosure may be implemented in various ways, not limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope thereof to those skilled in the art, and the present disclosure will only be defined by the appended claims. Like reference numerals refer to like elements throughout the specification. Detailed descriptions of generally known functions or constructions will be avoided in order to avoid obscuring the subject matter of the present disclosure. Although terms used in the present disclosure are defined in consideration of functions in the present disclosure, they may be changed according to intention or habit of a user or an operator. Accordingly, these definitions should be made not only by the actual terms used, but also by the inherent meaning of each term.

The BS, which is an entity responsible for allocating resources to the UE, may be at least one of gNode B, gNB, eNode B, eNB, node B, various radio access units including satellites, a Base Station Controller (BSC), or a network node. Further, the BS may be a network entity including at least one of an integrated access and backhaul donor (IAB donor), which is a gNB providing network access to the UE(s) through a network of backhaul and access links, or an IAB node, which is a Radio Access Network (RAN) node supporting NR access link(s) to the UE(s) and NR backhaul links to the IAB donor or any other IAB node in a 5G new wireless (NR) system. The UE may connect wirelessly through the IAB nodes and transmit and receive data to and from the IAB donor connected to the at least one IAB node via the backhaul link.

The UE may comprise an MS, a cellular phone, a smart phone, a computer or a multimedia system capable of performing communication functions. DL refers to a radio link on which a BS transmits signals to a UE, and UL refers to a radio link on which a UE transmits signals to a BS. Although the following description may be given in the context of an LTE or LTE-a system, as an example, embodiments may be applicable to other communication systems having similar technical contexts or channel types. For example, the communication system may include 5G mobile communication technology developed after LTE-a, and in the following description, 5G may conceptually cover legacy LTE, LTE-a, and other similar services. Furthermore, as will be appreciated by those skilled in the art, the present disclosure is also applicable to other communication systems without departing too much from the scope of the present disclosure.

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 loaded onto 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(s) and/or block diagram 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(s) and/or block diagram 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 operations 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 operations for implementing the functions/acts specified in the flowchart block(s) and/or block diagram block or blocks.

Furthermore, various block diagrams may illustrate portions of modules, segments, or code that include one or more executable instructions for performing particular logical function(s). Further, it should be noted that the functions of the blocks may be performed in a different order in several modified examples. For example, two consecutive blocks may be performed substantially simultaneously or they may be performed in reverse order according to their functions.

The term "unit" as used herein means, but is not limited to, a software component or a hardware component that performs certain tasks, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). The unit may advantageously be configured to reside on the addressable storage medium and configured to run on one or more processors. Thus, by way of example, a unit may include components (such as software components, object-oriented software components, class components, and task components), processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functionality provided for in the components and "units" may be combined into fewer components and "units" or further separated into additional components and "units". In addition, the components and "units" may be implemented such that they run on one or more Central Processing Units (CPUs) in a device or secure multimedia card. Further, in an embodiment, a "unit" may include at least one processor. Each "cell" herein may include circuitry.

A description will be given below of a basic structure of a 5G system using a millimeter wave (mmW) frequency band with reference to fig. 1a to 1e to assist in understanding the present disclosure.

Fig. 1a is a block diagram illustrating a Radio Access Network (RAN) and a Core Network (CN) in accordance with various embodiments.

According to various embodiments, RAN 150 may include at least one Distributed Unit (DU) 151, at least one central unit-control plane (CU-CP) 152, or at least one central unit-user plane (CU-UP) 153. Although RAN 150 is shown as being connected to at least one remote unit (or Radio Unit) (RU) 161, this is exemplary, and at least one RU 161 may be connected to RAN 150 or included in RAN 150. RAN 150 may be an open RAN (O-RAN). In this case, the DU 151 may be an open DU (O-DU), the CU-CP 152 may be an open CU-CP (O-CU-CP), the CU-UP 153 may be an open CU-UP (O-CU-UP), and the RU 161 may be an open RU (O-RU).

According to various embodiments, RU 161 may perform communications with UE 160. RU 161 may be a logical node that provides low physical layer (PHY) functionality and Radio Frequency (RF) processing. The DU 151 may be a logical node providing functions of a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a higher PHY layer, and is connected to, for example, the RU 161. CUs 152 and 153 may be logical nodes that provide the functions of Radio Resource Control (RRC), service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP). CU-CP 152 may be a logical node that provides the functionality of the control plane portion of RRC and PDCP. CU-UP 153 may be a logical node that provides the functionality of the user plane parts of the SDAP and PDCP.

According to various embodiments, a core network (e.g., a 5G core (5 GC) 154 may include at least one of an access and mobility management function (AMF) 155, a User Plane Function (UPF) 156, or a Session Management Function (SMF) 157. AMF 155 may provide functions of access and mobility management on a UE basis.

According to various embodiments, the gNB 101 of the 5G NR may include RU 161. The gNB 101 of fig. 1a has been described as being O-RAN based, the type of implementation is not limited, and it will be understood by those skilled in the art that the gNB 101 may be implemented in the form of a virtual RAN (V-RAN) or cloud RAN (C-RAN) based gNB or in the form of a legacy BS.

Fig. 1b is a block diagram illustrating a hardware configuration of a gNB in accordance with various embodiments.

According to various embodiments, the gNB 101 (or an electronic device configured to run the functionality of the gNB 101) may include at least one of a processor 120 (including processing circuitry), a storage device 130, or a communication module 190 including communication circuitry.

According to various embodiments, the processor 120 may control at least one other component (e.g., a hardware component or a software component) connected to the processor 120 of the gNB 101 (or an electronic device configured to perform the functions of the gNB 101), for example, by running software (e.g., a program), and perform various data processes or operations. According to an embodiment, as at least some of these data processes or operations, the processor 120 may store commands or data received from another component in the storage device 130, process the commands or data stored in the storage device 130, and store the resulting data in the storage device 130. According to an embodiment, the processor 120 may include at least some of a CPU, an application processor, a Neural Processing Unit (NPU), or a communication processor. However, the type of processor 120 is not limited. The NPU may include hardware structures dedicated to handling artificial intelligence models. The artificial intelligence model may include, but is not limited to, machine learning (e.g., reinforcement learning, supervised learning, unsupervised learning, or semi-supervised learning). The artificial intelligence model may include a plurality of artificial neural network layers. The artificial neural network may be one or a combination of one or more of the following, but is not limited to: deep Neural Network (DNN), convolutional Neural Network (CNN), recurrent Neural Network (RNN), constrained boltzmann machine (RBM), deep Belief Network (DBN), bi-directional recurrent deep neural network (BRDNN), deep Q network. In addition to or in lieu of hardware structures, the artificial intelligence model may include software structures. Those skilled in the art will appreciate that any device may be used as the storage device 130 so long as it is capable of storing data like a magnetic disk, such as a Hard Disk Drive (HDD). Each "processor" herein includes processing circuitry.

According to various embodiments, storage device 130 may store various data used by at least one component (e.g., processor 120 or communication module 190) of the gNB 101 (or an electronic device configured to run the functionality of the gNB 101). The data may include, for example, software, input data or output data for instructions associated with the software.

According to various embodiments, the communication module 190 may support establishing a direct (e.g., wired) communication channel or a wireless communication channel, and supporting communication between the gNB 101 (or an electronic device configured to operate the functionality of the gNB 101) and an external electronic device (e.g., an E2 node) over the established communication channel. For example, the type of the communication module 190 is not limited as long as it can support the E2 interface. When the gNB 101 and the RAN 150 are implemented as a single device, the communication module 190 with communication circuitry may be an interface for both entities.

Fig. 1c is a diagram showing a basic structure of a time-frequency region, which is a radio resource region carrying data or control channels in a 5G system.

In fig. 1c, the horizontal axis represents time, and the vertical axis represents frequency. In the time and frequency domains, the basic unit of resource is a Resource Element (RE) 110, which can be defined as one OFDM symbol 102 on the time axis times one subcarrier 103 on the frequency axis. In the frequency domain of the power supply,(E.g., 12) consecutive REs may form one Resource Block (RB) 104. In the case of the figure 1c of the drawings,The number of OFDM symbols per subframe 111 is configured μ for subcarrier spacing (SPS), and for a more detailed description of the resource structure in a 5G system, please refer to TS 38.211 section 4.

Fig. 1d is a diagram illustrating a slot structure considered in a 5G system.

In fig. 1d, an exemplary structure of frame 116, subframe 111, and slots 112 and 113 is shown. One frame 116 may be defined as 10ms. One subframe 111 may be defined as 1ms, and thus, one frame 116 may include a total of 10 subframes 111. One slot 112 or 113 may be defined as 14 OFDM symbols (e.g., number of symbols per slot)). One subframe 111 may include one or more slots 112 or 113, and the number of slots per subframe may be different according to SCS (subcarrier spacing) configuration values μ 114 or 115. In the example of fig. 1d, the case of μ=0 114 and the case of μ=1 115 are shown as SCS configuration values. When μ=0 114, one subframe 111 may include one slot 112, and when μ=1 115, one subframe 111 may include two slots 113. That is, the number of slots per subframe/>Can be varied according to SCS configuration value μ, and accordingly, the number of slots per frame/>May vary.

In fig. 1e, an example is shown in which the UE bandwidth 123 is configured to include two BWP (i.e., bwp#1 121 and bwp#2 122). The gNB may configure one or more BWPs for the UE. For each BWP, "locationAndBandwidth" indicates a location and bandwidth of the BWP in the frequency domain, "subcarrierSpacing" indicates SCS to be used in the BWP, and "cyclicPrefix" may configure information indicating whether or not an extended Cyclic Prefix (CP) is used in the BWP.

The 5G supported BWP configuration may be used for various purposes.

According to some embodiments, this may be supported by a BWP configuration when the bandwidth supported by the UE is smaller than the system bandwidth. For example, the gNB may configure the frequency location of BWP for the UE such that the UE may send and receive data at a particular frequency location within the system bandwidth.

According to embodiments, the gNB may configure multiple BWPs for the UE in order to support different parameter sets. For example, in order to support data transmission and reception for a UE using both an SCS of 15kHz and an SCS of 30kHz, the gNB may configure the SCS to be two BWPs of 15kHz and 30kHz, respectively. Different BWPs may be multiplexed in Frequency Division Multiplexing (FDM), and when data is transmitted/received in a specific SCS, BWPs configured with the specific SCS may be activated.

According to an embodiment, in order to reduce the power consumption of the UE, the gNB may also configure the UE with BWP with different bandwidths. For example, when a UE supports a very large bandwidth (e.g., 100 MHz) and always uses the bandwidth to transmit and receive data, the UE may have very large power consumption. In particular, unnecessary listening to the DL control channel with a large bandwidth of 100MHz in the absence of traffic may be very inefficient in terms of power consumption. In order to reduce the power consumption of the UE, the gNB may configure the UE with BWP having a relatively small bandwidth, e.g., 20MHz BWP. In the absence of traffic, the UE may perform a listening operation in 20-MHz BWP, however when data is generated, the UE may transmit/receive data in 100-MHz BWP according to an instruction from the gNB.

Fig. 2 is a diagram illustrating CoMP operations for a UE at a cell edge in accordance with various embodiments. Each embodiment herein may be used in combination with any other embodiment described herein.

According to various embodiments, the types of CoMP techniques applicable when the cell(s) transmit data to the UE may be classified according to the degree of coordination between cells and traffic load. For example, in Coordinated Scheduling (CS) and Coordinated Beamforming (CB) for DL CoMP, one transmission cell may be selected from among the cooperating cells to minimize or reduce interference signals for cell-edge UEs and to communicate with the UEs. For example, interference information may be transmitted on a cell basis in inter-cell interference coordination (ICIC), whereas channel information may be transmitted on a user basis in CS CoMP. For example, cell a 201 and cell B202 cooperate to avoid interference by allocating different frequency resources to UE A1 203 and UE B1 204 located at the cell edge.

Referring to fig. 2, when performing CB CoMP operation, different spatial resources (beam pattern 1 and beam pattern 2) may be allocated to UE a1203 and UE B1 204 by using an antenna technique, and the same frequency resource f3 may be allocated to UE A1203 and UE B1 204. For example, when a main beam is allocated to a UE to be served and a null beam is allocated to a neighbor cell UE, interference may be reduced. Therefore, even though UE A1203 and UE B1 204 use the same frequency resource f3, they can receive data from only their serving cells (cell a 201 and cell B202), respectively.

According to various embodiments, CB CoMP operations may be used with CS CoMP operations. For example, when CS CoMP operation and CB CoMP operation are used together, cell a 201 and cell B202 may cooperate to allocate different frequency resources f3 and f2 and different spatial resources (beam pattern 1 and beam pattern 2) to UE A1 203 and UE B1 204. Thus, UE A1 203 and UE B1 204 may receive data only from their serving cells (cell a 201 and cell B202), respectively. Thus, with CoMP operation, the serving UE located at the cell edge can avoid interfering with the signal of the other party and can improve the reception quality of the signal.

According to various embodiments, serving gNB 205 and assisting gNB 206 may be connected to each other (directly or indirectly) via a backhaul, such as at least an Xn interface, e.g., UEs located within at least serving cell 201 may be referred to as serving UE 203, and serving UE 203 may refer to a UE for which CoMP operations are to be performed by assisting gNB 206 (hereinafter, target CoMP UE). The assisting gNB 206 may refer to a gNB that performs CoMP for the serving UE 203. Serving gNB 205 and/or helping gNB 206 may be, but is not limited to, for example, gNB 101.

Fig. 3 is a diagram illustrating an MCS level that increases according to SINR in accordance with various embodiments.

According to various embodiments, coMP operations for which link adaptation algorithms are considered may be performed on a slot basis, like DL or UL scheduling units in a 5G NR system, but are not limited to. For example, in the case of 30khz SCS103, one slot may be 0.5ms, and the duration of each slot may be flexible for each SCS according to various parameter sets. In CoMP operation, there is no set rule or specification to determine a UE for which CoMP operation is to be performed in each slot. In CoMP operations that consider the generic link adaptation algorithm, the serving UE (e.g., target CoMP UE) for which the CoMP operations are performed during a predetermined duration in each slot may be the same or changed. For example, when a serving UE changes, the serving UE may be determined from the scheduling metrics. For example, the scheduling metric may be a Round Robin (RR) method that selects on a round robin basis or a Proportional Fair (PF) method that selects based on the ratio of instantaneous throughput to average throughput.

According to various embodiments, a low MCS level for data transmission may result in a low data rate even when the SINR of the wireless channel between the UE and the gNB is high. In addition, when SINR of a wireless channel is low, even an increase in MCS level for data transmission may cause a low data rate and failure of data transmission. Thus, applying an appropriate MCS level according to the SINR case of the wireless channel can increase the data rate according to the channel environment.

According to various embodiments, a maximum or large number of allowed retransmissions may affect the determination of the MCS level when applying hybrid automatic repeat request (HARQ). In the case of having a high SINR, a predetermined number or more of HARQ Acknowledgement (ACK) feedback receptions are necessary to raise the MCS level according to the link adaptation algorithm. However, when SINR increases rapidly, it may be difficult to rapidly increase the MCS level by waiting for a predetermined number or more of HARQ ACK feedback receptions.

Referring to fig. 3, SINR or MCS levels (on the X-axis) over time are shown. For example, SINR rises faster in the case of SINR 1 than in the case of SINR 2. For example, when the MCS level is raised according to a predetermined number of HARQ ACK feedback receptions, the MCS level may be raised at the same rate regardless of the cases of SINR 1 and SINR 2. In other words, since an increase in the MCS level requires a predetermined number of HARQ ACK receptions, the MCS level increases at the same rate. Thus, when the MCS level can be rapidly increased in the case of high SINR, the packet loss rate and delay can be reduced.

Fig. 4a is a diagram showing a variation trend according to execution of CoMP operation according to SINR 402 and MCS level 403 of a comparative example for comparison with various embodiments. Fig. 4b is a diagram showing an increase in MCS level according to HARQ ACK retransmission according to the comparative example. Fig. 4c is a diagram showing a variation trend of SINR and MCS level 403 according to the CoMP operation according to the comparative example. At least some of the operations performed by the gNB according to the comparative example may also be performed by the gNB according to various embodiments.

According to various embodiments, SINR 402a in the case where CoMP operation is applied may be greater than SINR 402b in the case where CoMP operation is not applied. Referring to fig. 4a, a solid line 401 may indicate a case where CoMP operation is performed and a case where CoMP operation is not performed. For example, when the solid line 401 is high, this may indicate that CoMP operations are performed. In this case, a relatively high SINR 402a may be obtained. For example, when the solid line 401 is low, this may indicate that CoMP operations are not performed. In this case, a relatively low SINR 402b may be obtained. For example, while CoMP operations are shown as being performed during approximately 50% of the time period, this is illustrative and not limiting of the present disclosure. The transition of the solid line 401 from low to high may indicate an increase in SINR as CoMP operations are performed. Referring to a solid line 401 indicating SINR according to execution of CoMP operation in fig. 4c, a period of time during execution of CoMP operation may be shorter than in the example of fig. 4 a. In the example of fig. 4a, the CoMP operation is performed during a sufficient period of time so that the MCS level 403 may be raised to a certain level, whereas in the example of fig. 4c, the CoMP operation is performed during a relatively short period of time as compared to the example of fig. 4a, and thus the MCS level 403 may be raised only up to a lower level than in fig. 4a and then lowered. In other words, even if SINR increases due to CoMP operation, if a time sufficient to raise an MCS level is not guaranteed by the link adaptation algorithm, an increase in throughput of data transmission may be smaller than that of SINR.

Referring to fig. 4b, the mcs level is shown to be raised according to a predetermined number of HARQ ACK feedback 421 receptions. For example, according to HARQ operation in a conventional wireless communication system, after one data packet is transmitted, an ACK indicating successful reception or a NACK indicating reception failure may be received from a data packet receiver. In general, for an MCS level selected in consideration of channel characteristics, a channel state may be determined based on the number of times of reception of an ACK response indicating data feedback to identify whether the channel state between the UE and the gNB is good.

Referring to fig. 4b, the gNB 411 may raise the MCS level when a predetermined number (n) of HARQ ACK feedback 421 is received from the UE 412 (402). For example, when the gNB 411 transmits a first DL data packet to the UE 412, the UE 412 may transmit a first ACK indicating receipt of the first data packet. Then, when the gNB 411 transmits the nth DL data packet to the UE 412 and the UE 412 transmits the nth ACK (421) to the gNB 411, the gNB 411 may raise the MCS level by a predetermined level (e.g., every +1), thereby determining that the channel quality with the UE 412 is good (402).

In general, when CoMP operation is performed according to the link adaptation algorithm, increasing the MCS level by the link adaptation algorithm requires time taken to receive n HARQ feedback even when the SINR increases rapidly as described above. For example, since raising the MCS level 403 requires a time taken to receive n HARQ ACKs, when CoMP is applied for a short time and the SINR increment (the difference between SINR 402a and SINR 402 b) is large depending on whether CoMP operation is performed, it may be difficult to sufficiently raise the MCS level unless a period is guaranteed, in which the MCS level may be raised as much as the SINR increment.

According to various embodiments, the SINR of the target CoMP UE may fluctuate when the target CoMP UE changes in each slot or each short period. Referring to fig. 4c, when there are a plurality of target CoMP UEs from the perspective of the gNB performing the CoMP operation, the gNB may perform the CoMP operation for the plurality of UEs in the time domain. In this case, at least one UE of the plurality of UEs may be determined as a target CoMP UE, and the determination may be made based on the CSI feedback period for DL and the SRS transmission period for UL.

Fig. 5a is a diagram showing a variation trend of SINR and MCS levels when CoMP operation is performed according to an embodiment. Fig. 5b is an enlarged view illustrating a rising period of the MCS level of fig. 5 a. Fig. 5c is a flowchart illustrating an operation of adjusting an MCS level according to whether CoMP operation is applied together with link adaptation algorithm operation.

Referring to fig. 5a, a solid line 500 may indicate whether CoMP operation is applied, and a dotted line 510 may indicate a trend of variation of MCS level. In addition, a rising period 501, a holding period 502, and a falling period 503 of the MCS level are shown.

According to various embodiments, the MCS level may be raised and maintained by a link adaptation algorithm when CoMP operations are being performed. Referring to fig. 5a, sinr may rise to a relatively high value 402a at an on timing of CoMP operation (CoMP on notification) (indicated by a message notifying the start of CoMP operation), and may rise to a certain level faster than in the comparative example during a rising period 501 from the on timing (CoMP on notification). Thereafter, the MCS level may be maintained while CoMP operations are being performed (e.g., during the hold period 502). In comparison with the cases of fig. 4a and 4c, during the rising period 501 of the MCS level in fig. 5a, the rising inclination angle of the MCS level may be large and the MCS level may be raised at a high rate.

The gNB 101 according to various embodiments may raise the MCS level relatively quickly in a link adaptation algorithm based on a reduction in the number of HARQ feedback required to raise the MCS level and/or an increase in the MCS level increment in general, which will be described later. Although the MCS level is not sufficiently raised or sufficiently maintained with respect to the SINR delta in the case of fig. 4a and 4c, it may be noted in fig. 5a that the MCS level is maintained even after reaching a certain level.

According to various embodiments, the on-timing of CoMP operations may be configured in consideration of SINR delta (e.g., the difference between 402a and 402b in fig. 4a, 4c, and 5 a) depending on whether CoMP operations are performed.

According to various embodiments, since it is not necessary to maintain the MCS level high when CoMP operation is not performed, the gNB 101 can rapidly decrease the MCS level according to the off timing of CoMP operation. The MCS level reduction rate during the illustrated MCS decrease period 503 may be higher than the MCS level reduction rates illustrated in fig. 4a, 4b and 4c, which should not be construed as limiting. When the MCS level is rapidly reduced during a period in which CoMP operation is not performed, an unnecessary data transmission loss rate and CRC failure probability may be reduced, and throughput loss caused by HARQ retransmission may be minimized or reduced.

According to various embodiments, a serving gNB (hereinafter, referred to as a first gNB) may rapidly raise an MCS level according to an application time of CoMP operation. For example, the first gNB may receive a notification indicating an on/off timing of the CoMP operation from a helping gNB (hereinafter, referred to as a second gNB) that is connected to the first gNB through a backhaul and performs a cooperative operation with the first gNB. For example, upon receiving a notification of the start of a CoMP operation (CoMP on notification), the first gNB may recognize that the CoMP operation is performed at the indicated timing and maintained during a certain period until before receiving a notification for terminating the CoMP operation (CoMP off notification). In other words, the second gNB may send a notification to terminate CoMP operations after a certain duration. For example, the link adaptation algorithm may provide MCS level rise and hold periods based on CoMP on notification and CoMP off notification. Accordingly, when the rising period 501 and the holding period 502 of the MCS level coincide with the period in which the CoMP operation is applied, the throughput gain of the data transmission can be maximized or improved.

According to various embodiments, the first gNB may adjust the MCS level even before less than a predetermined number of HARQ feedback is received from the UE by preliminarily reflecting an increment or decrement of SINR based on whether CoMP operations are performed in the link adaptation algorithm.

Referring to fig. 5c, in operation 511, the first gNB may receive a CoMP activation notification message. In operation 512, the first gNB may identify whether to start CoMP operations at a timing indicated by information included in the received message. When CoMP operation starts (512-yes), the first gNB may receive HARQ feedback k times according to SINR increments based on execution of the CoMP operation in operation 513. In operation 515, the first gNB may raise the MCS level by a predetermined level (e.g., by 1) based on k HARQ feedback receptions. The HARQ feedback of the elevated MCS level is ACK and the HARQ feedback of the lowered MCS level is NACK. When CoMP operation does not start (512-no), the first gNB may receive HARQ feedback n times in operation 514. Based on the n HARQ feedback receptions, the first gNB may raise the MCS level by a predetermined level (e.g., by 1) in operation 515. Here, n may be a natural number greater than k, and may be, but is not limited to, a value set for a case where CoMP operation is not performed. As described above, as the MCS level increases based on k HARQ feedback receptions, the MCS level may increase at a higher rate than based on n HARQ feedback receptions. Thereafter, the MCS level may be raised. In operation 516, the first gNB may maintain the MCS level during a predetermined period. Even if the MCS level converges to a certain level, the MCS level may be lowered (not shown) when NACK is received as HARQ feedback. In operation 517, the first gNB may receive a CoMP shut down notification. The first gNB may terminate CoMP operations based on receipt of the CoMP shut down notification. The first gNB may maintain CoMP operations prior to termination. When CoMP operation is terminated, the first gNB may reduce the MCS level based on only a small amount of HARQ feedback reception in consideration of SINR reduction.

According to various embodiments, the duration of CoMP operations may be manually set according to the preferences of the serving operator. For example, when SINR changes rapidly depending on whether CoMP operation is performed, the time taken for the link adaptation algorithm to converge the MCS level to a predetermined level by increasing (or decreasing) the MCS level may be determined by various factors such as a moving speed of the UE, a target area, frequency Division Duplex (FDD)/Time Division Duplex (TDD), a slot pattern, characteristics of an application service, and the like, and may vary depending on situations.

According to various embodiments, it may be necessary to manually set a holding period of an MCS level in consideration of characteristics of an operating system and a region in which CoMP operations are performed. For example, convergence to an appropriate MCS level depending on whether CoMP operation is performed may indicate such a case: by meeting the target block error rate (BLER), DL data transmission becomes possible. For reference, maximum or high throughput may be achieved when the target BLER for eMBB services is set to about 10% to 15%. For example, the gNB (e.g., helping the gNB) may identify the movement speed of the UE and manually set the target BLER. For example, when the moving speed of the UE is high, the MCS level may be set low in a rapidly changing channel environment. For example, the required BLER in a particular region may be set based on a database, and/or a higher BLER in TDD where the HARQ feedback reception rate is slower than in FDD. In addition, since the data transmission amount and frequency are different depending on the service of the application, the target BLER can be set in consideration of the service time required for each service of the application. As the target BLER index is set higher, the tilt angle of the MCS level may increase. The rate of rise of the MCS level may be adjusted according to the setting of the target BLER.

According to various embodiments, a relatively low value of less than 1% may be expected in a period 501 in which the MCS level increases sharply, while a relatively high BLER may be expected in a period 503 in which the MCS level decreases rapidly (see, e.g., fig. 5 a). For example, the rising period 501 and the holding period 502 of the MCS level may be configured to meet or maximize a quality of service (QoS) of the target CoMP UE. For example, for a UE that uses non-guaranteed bit rate (non-GPR) services, the service time may be determined as the smaller between the ratio of the data volume to the average throughput and the reporting period of the measurement report. Further, it may be considered that the service time required by the application or CoMP operation duration may be manually adjusted by the service operator.

According to an embodiment, conventionally, the criterion for selecting the target CoMP UE is based on information related to channel quality of DL and UL signals, and thus may be determined by CSI transmission period and SRS transmission period. In contrast, the MCS level rise and hold period may be considered in consideration of the link adaptation algorithm. As used herein, "based on" encompasses at least based on.

Fig. 6a is a diagram illustrating the operation of a serving gNB and a helping gNB according to an embodiment. Fig. 6b is a flowchart illustrating operation from the perspective of the service gNB according to an embodiment.

Referring to fig. 6a, assist gNB 620 may notify serving gNB 610 over at least a wired backhaul connection such as an Xn interface of CoMP operational status (e.g., on and/or off of CoMP operations). In operation 601, the serving gNB 610 may receive a CoMP state notification message indicating a CoMP operating state. For example, the CoMP status notification message may include the status (on or off) of the System Frame Number (SFN)/slot based CoMP operation for the first gNB, and optionally scheduling related information such as: the position of a Physical Resource Block (PRB) in which CoMP operation is performed, the number of nulling layers in the case of beam nulling, and CSI-related information depending on whether SINR increment and/or decrement of CoMP operation is applied can be derived therefrom. In operation 602, serving gNB 610 may send a response (e.g., coMP status notification acknowledgement) to helping gNB 620 indicating receipt of the message. For example, when serving gNB 610 has successfully received the CoMP status notification message, serving gNB 610 may send a CoMP status notification acknowledgement, otherwise serving gNB 610 may send a NACK. For example, serving gNB 610 may raise the MCS level at 603.

According to an embodiment, serving gNB 610 serving the target CoMP UE may identify an on timing and/or an off timing of the CoMP operation from a message indicating on/off of the CoMP operation between serving gNB 610 performing the CoMP operation and helping gNB 620. For example, serving gNB 610 may determine MCS level increments and/or decrements based on the identified on and/or off timings of CoMP operations.

Referring to fig. 6b, in operation 611, a first (e.g., serving) gNB 610 may receive a message from a second gNB 620 that includes at least one piece of information related to whether to perform CoMP operations for UEs connected to the first gNB 610. In operation 612, the first gNB 610 may perform CoMP operations at a timing indicated based on at least a portion of the at least one piece of information included in the received message. In operation 613, the first gNB 610 may raise the MCS level during a first period (e.g., 501 of fig. 5) from the timing of performing the CoMP operation. In operation 614, the first gNB 610 may maintain the MCS level during a second period (e.g., 502 of fig. 5) after the MCS level reaches the specified first level.

Fig. 7a is a diagram illustrating an increase in MCS level according to the HARQ ACK reception times according to an embodiment. Fig. 7b is a diagram illustrating a case where the MCS level is increased by 1 or more according to an embodiment. Fig. 7c is a flowchart illustrating an operation of rapidly increasing an MCS level according to an embodiment.

In general, the link adaptation algorithm includes weight-related parameters that raise or lower the MCS level according to HARQ ACK/NACK reception. The MCS level may be raised or lowered by increasing the weight. The weight may be used to determine the number of HARQ feedback receptions that will then raise the MCS level or the number of NACK receptions that will then lower the MCS level. For example, the weights may include parameters related to increasing or decreasing MCS levels.

Referring to fig. 7a, it can be noted that the tilt angle in the case where the MCS level is raised by 1 every k times ACK reception 702 is larger than the tilt angle in the case where the MCS level is raised by 1 every n times ACK reception 701, where k is an integer smaller than n.

According to various embodiments, the MCS level may be rapidly increased by reducing the number of HARQ feedback receptions. Further, when a condition for raising the MCS level (for example, the HARQ feedback reception number) is satisfied, the MCS level may be raised by 1 or more, thereby rapidly raising the MCS level to a convergence value. For example, the convergence MCS level may be predicted based on the maximum/minimum value of the MCS level reached when CoMP operation is applied or not applied in the past. Or the converged MCS level may be derived by referring to a change in a Channel Quality Indication (CQI) value in a periodic/aperiodic CSI report transmitted by the UE.

According to various embodiments, the first gNB 610 may adjust the MCS level by preliminarily reflecting SINR increments depending on whether CoMP operations are performed in the link adaptation algorithm. For example, with respect to a method of preliminarily reflecting SINR increments in a link adaptation algorithm, referring to fig. 7b, the first gNB, which knows the on-timing of CoMP operation, may raise the MCS level by 3 as indicated by reference numeral 704 instead of by 1 as indicated by reference numeral 703 whenever the HARQ ACK reception times reach a threshold.

According to various embodiments, when SINR increments can be predicted depending on whether CoMP operations are performed, MCS level increments mapped to SINR increments can be identified. For example, the manufacturer or service provider may determine the MCS level mapped to the SINR delta from the SINR-to-MCS mapping table.

Referring to fig. 7c, operations of the first gNB to raise the MCS level more quickly are shown. The first gNB may transmit DL data in operation 711 and receive ACK feedback or NACK feedback for DL data reception from the UE in operation 712. For example, upon receiving a NACK (712-NACK) from the UE, the first gNB may repeat operation 711 to retransmit the DL data. For example, upon receiving an ACK (712-ACK) from the UE, the first gNB identifies whether k ACKs have been received (k is an integer less than the HARQ feedback reception number n, which will typically be raised later by the MCS level, indicating a threshold for raising the MCS level) in operation 713. When the number of ACK receptions is n or k (yes in 713), the first gNB may raise the MCS level by 1 in operation 714. For example, when the first gNB knows the MCS level convergence value in advance, the first gNB may raise the MCS level by 1 or more to quickly reach the convergence value (715-no). In operation 716, the first gNB may maintain the MCS level that has reached the convergence value until the CoMP operation is terminated. Even if the MCS level converges to a certain level, the MCS level may be lowered (not shown) when NACK is received as HARQ feedback.

According to various embodiments, a method of operating a first BS for performing wireless communication with a UE includes: receiving a message from a second BS connected to the first BS, the message including at least one piece of information associated with whether to perform CoMP operations for UEs connected (directly or indirectly) to the first BS; when the received message includes information indicating the start of the CoMP operation, performing the CoMP operation at a timing indicated based on at least a portion of at least one piece of information included in the received message, raising an MCS level during a first period, and maintaining the performed CoMP operation during a second period after the MCS level reaches a specified first level based on the raising during the first period; and terminating the CoMP operation at a timing indicated based on at least a portion of at least one piece of information included in the received message and reducing the MCS level during the third period when the received message includes information indicating termination of the CoMP operation.

According to various embodiments, the method comprises: the MCS level is raised by 1 or more when the HARQ ACK reception number reaches the threshold, or lowered by 1 or more when the HARQ NACK reception number reaches the threshold.

According to various embodiments, the second period is determined based on a minimum or low value between a service time according to the data amount per average throughput of the UE and the period of the measurement report.

According to various embodiments, at least one of the first period, the second period, or the third period can be set to any duration by the service operator.

According to various embodiments, the first BS and the second BS are connected to each other (directly or indirectly) via at least a backhaul, and the received message includes information indicating whether to perform CoMP operations on a slot basis for the SFN, and includes at least one of: the location of PRBs in which CoMP operation is performed, the number of zeroing layers, or information related to SINR delta according to the start of CoMP operation.

According to various embodiments, the method further comprises: an ACK is sent to the second BS in response to the received message.

According to various embodiments, the method comprises: an SINR delta based on (e.g., according to) the start of CoMP operation is identified based on at least a portion of at least one piece of information included in the received message and the MCS level is raised by 1 or more based on the SINR delta, or an SINR decrement based on (e.g., according to) the termination of CoMP operation is identified based on at least a portion of at least one piece of information included in the received message and the MCS level is lowered by 1 or more based on the SINR decrement.

According to various embodiments, the increase in MCS level during the first period is adjusted by adjusting a parameter related to the number of HARQ ACK/NACK receptions from the UE.

According to various embodiments, after the MCS level converges to the first level, the MCS level is maintained at the first level during the second period.

According to various embodiments, the first level is determined based on at least one of: based on (e.g., according to) the SINR delta of the start of CoMP operation, the maximum MCS level value or high MCS level value reached in the previous CoMP operation, or the CQI value in the CSI report of the UE.

According to various embodiments, a first BS for performing wireless communication with a UE includes: a transceiver; and at least one processor including processing circuitry. The at least one processor is configured to: receiving, by the transceiver, a message from a second BS connected (directly or indirectly) to the first BS, the message including at least one piece of information associated with whether CoMP operations are performed for a UE connected to the first BS; when the received message includes information indicating the start of the CoMP operation, performing the CoMP operation at a timing indicated based on at least a portion of at least one piece of information to be included in the received message, raising an MCS level during a first period, and maintaining the performed CoMP operation during a second period after the MCS level reaches a specified first level based on the raising during the first period; and terminating the CoMP operation at a timing indicated based on at least a portion of at least one piece of information to be included in the received message, and lowering the MCS level during the third period, when the received message includes information indicating termination of the CoMP operation.

According to various embodiments, the at least one processor is configured to: the MCS level is raised by 1 or more when the HARQ ACK reception number reaches the threshold, or lowered by 1 or more when the HARQ NACK reception number reaches the threshold.

According to various embodiments, the at least one processor is further configured to: an ACK is sent by the transceiver to the second BS in response to the received message.

According to various embodiments, the at least one processor is configured to: an SINR delta based on (e.g., according to) the start of CoMP operation is identified based on at least a portion of at least one piece of information to be included in the received message and the MCS level is raised by 1 or more based on the SINR delta, or an SINR decrement based on (e.g., according to) the end of CoMP operation is identified based on at least a portion of at least one piece of information to be included in the received message and the MCS level is lowered by 1 or more based on the SINR decrement.

According to various embodiments, the at least one processor is configured to: the increase is adjusted by adjusting a parameter related to the number of HARQ ACK/NACK receptions from the UE.

According to various embodiments, the at least one processor is configured to: the first level is determined based on at least one of: based on the SINR delta at the beginning of CoMP operation, the maximum MCS level value or high MCS level value reached in the previous CoMP operation, or the CAI value in the CSI report of the UE.

It should be understood that the various embodiments of the disclosure and the terminology used therein are not intended to limit the technical features set forth herein to the particular embodiments, but rather include various modifications, equivalents or alternatives to the respective embodiments. For the description of the drawings, like reference numerals may be used to refer to like or related elements. It will be understood that a noun in the singular corresponding to a term may include one or more things unless the context clearly indicates otherwise. As used herein, each of the phrases such as "a or B", "at least one of a and B", "at least one of a or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B or C" may include any or all possible combinations of the items listed with the corresponding one of the plurality of phrases. As used herein, terms such as "1 st" and "2 nd" or "first" and "second" may be used to simply distinguish one element from another element and not to limit the element in other respects (e.g., importance or order). It will be understood that if the terms "operatively" or "communicatively" are used or the terms "operatively" or "communicatively" are not used, then if an element (e.g., a first element) is referred to as being "coupled to," "connected to," or "connected to" another element (e.g., a second element), it is intended that the element can be directly (e.g., wired) connected to the other element, wirelessly connected to the other element, or connected to the other element via at least one third element.

As used in connection with various embodiments of the present disclosure, the term "module" may include an element implemented in hardware, software, or firmware, and may be used interchangeably with other terms (e.g., "logic," "logic block," "portion," or "circuitry"). A module may be a single integrated component adapted to perform one or more functions or a minimal unit or portion of the single integrated component. For example, according to an embodiment, a module may be implemented in the form of an Application Specific Integrated Circuit (ASIC).

The various embodiments set forth herein may be implemented as software (e.g., a program) comprising one or more instructions stored in a storage medium (e.g., internal memory or external memory) readable by a machine (e.g., the gNB 101). For example, under control of a processor, a processor (e.g., processor 120) of the machine (e.g., gNB 101) may invoke and execute at least one instruction of the one or more instructions stored in the storage medium with or without the use of one or more other components. This enables the machine to operate to perform at least one function in accordance with the at least one instruction invoked. The one or more instructions may include code generated by a compiler or code capable of being executed by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Wherein the term "non-transitory" merely means that the storage medium is a tangible device and does not include a signal (e.g., electromagnetic waves), but the term does not distinguish between data being semi-permanently stored in the storage medium and data being temporarily stored in the storage medium.

According to embodiments, methods according to various embodiments of the present disclosure may be included and provided in a computer program product. The computer program product may be used as a product for conducting transactions between sellers and buyers. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disk read only memory (CD-ROM)), or may be distributed (e.g., downloaded or uploaded) online via an application Store (e.g., play Store ^TM), or may be distributed (e.g., downloaded or uploaded) directly between two user devices (e.g., smart phones). At least some of the computer program product may be temporarily generated if published online, or at least some of the computer program product may be stored at least temporarily in a machine readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a forwarding server.

According to various embodiments, each of the above-described components (e.g., a module or a program) may include a single entity or multiple entities, and some of the multiple entities may be separately provided in different components. According to various embodiments, one or more of the above components may be omitted, or one or more other components may be added. Alternatively or additionally, multiple components (e.g., modules or programs) may be integrated into a single component. In this case, according to various embodiments, the integrated component may still perform the one or more functions of each of the plurality of components in the same or similar manner as the corresponding one of the plurality of components performed the one or more functions prior to integration. According to various embodiments, operations performed by a module, a program, or another component may be performed sequentially, in parallel, repeatedly, or in a heuristic manner, or one or more of the operations may be performed in a different order or omitted, or one or more other operations may be added.

Claims

1. A method of operating a first base station, BS, for performing wireless communication with a user equipment, UE, the method comprising:

Receiving a message from a second BS connected to the first BS, the message including at least one piece of information associated with whether to perform coordinated multipoint CoMP operation for a UE connected to the first BS;

When the received message includes information about the start of the CoMP operation, performing the CoMP operation at a timing indicated based on at least a portion of the at least one piece of information included in the received message, raising a modulation and coding scheme MCS level during a first period, and maintaining the CoMP operation performed during a second period after the MCS level reaches a specified first level based on the raising during the first period; and

Based on the received message including information regarding termination of the CoMP operation, terminating the CoMP operation at a timing based on at least a portion of the at least one piece of information included in the received message, and reducing the MCS level during a third period.

2. The method of claim 1, the method further comprising: the MCS level is raised by 1 or more when the number of hybrid automatic repeat request HARQ acknowledgement ACK receptions reaches a threshold and/or lowered by 1 or more when the number of HARQ negative ACK receptions reaches a threshold, i.e. NACK.

3. The method of claim 1, wherein the second period is determined based on a minimum and/or low value between a service time according to a data amount per average throughput of the UE and a period of measurement reporting.

4. The method of claim 1, wherein at least one of the first period, the second period, or the third period is settable by a service operator.

5. The method of claim 1, wherein the first BS and the second BS are connected to each other via at least a backhaul, and the received message includes information indicating whether to perform the CoMP operation on a slot basis for a system frame number SFN, and includes at least one of: the location of physical resource blocks PRBs in which the CoMP operation is performed, the number of zeroing layers, or information related to a signal to interference and noise ratio SINR delta according to the start of the CoMP operation.

6. The method of claim 1, the method further comprising: and sending an ACK to the second BS in response to the received message.

7. The method of claim 1, the method further comprising: an SINR delta based on a start of the CoMP operation is identified based on the at least a portion of the at least one piece of information included in the received message and the MCS level is raised by at least 1 based on the SINR delta, and/or an SINR decrement based on a termination of the CoMP operation is identified based on the at least a portion of the at least one piece of information included in the received message and the MCS level is lowered by at least 1 based on the SINR decrement.

8. The method of claim 1, wherein the increase in the MCS level during the first period is adjusted by adjusting at least one parameter related to a number of HARQ ACK/NACK receptions from the UE.

9. The method of claim 1, wherein the MCS level is maintained at the first level during the second period after the MCS level converges to the first level.

10. The method of claim 1, wherein the first level is determined based on at least one of: based on the SINR delta at the beginning of the CoMP operation, the maximum MCS level value and/or the high MCS level value reached in the previous CoMP operation, or the channel quality indication CQI value in the channel state information CSI report of the UE.

11. A first base station, BS, for performing wireless communication with a user equipment, UE, the first BS comprising:

a transceiver; and

At least one of the processors is configured to perform,

Wherein the at least one processor is configured to:

Receiving, by the transceiver, a message from a second BS connected to the first BS, the message including at least one piece of information associated with whether to perform coordinated multipoint CoMP operations for UEs connected to the first BS;

based on the received message including information indicating the start of the CoMP operation, controlling to perform the CoMP operation at a timing indicated based on at least a portion of the at least one piece of information included in the received message, raising a modulation and/or coding scheme MCS level during a first period, and maintaining the performed CoMP operation during a second period after the MCS level reaches a specified first level based on the raising during the first period; and

Based on the received message including information indicating termination of the CoMP operation, control is performed to terminate the CoMP operation at a timing based on at least a portion of the at least one piece of information included in the received message, and reduce the MCS level during a third period.

12. The first BS of claim 11, wherein the at least one processor is further configured to: the MCS level is raised by at least 1 based on the number of hybrid automatic repeat request HARQ acknowledgement, ACK, receptions reaching a threshold and/or is controlled to be lowered by at least 1 based on the number of HARQ negative ACK receptions reaching a threshold, i.e. NACK.

13. The first BS of claim 11, wherein the second period is determined based on a minimum and/or low value between a service time according to a data amount per average throughput of the UE and a period of measurement reporting.

14. The first BS of claim 11, wherein at least one of the first period, the second period, or the third period is settable by a service operator to any duration.

15. The first BS of claim 11, wherein the first BS is configured to: is connected to the second BS via at least a backhaul, and the received message will include information indicating whether to perform the CoMP operation on a slot basis for a system frame number SFN, and at least one of: the location of physical resource blocks PRBs in which the CoMP operation is performed, the number of zeroing layers, or information related to a signal to interference and noise ratio SINR delta according to the start of the CoMP operation.