TR2022014234A1 - A RETRANSMISSION METHOD BASED ON RATE DIVISION MULTI ACCESS NETWORKS - Google Patents

Abstract

The invention relates to a computer-implemented method for retransmission of wireless networks, especially in 5G and B5G networks, that uses rate division as a multi-access approach to provide multi-user service, and to a system configured to perform said method.

Description

DESCRIPTION A RETRANSMISSION BASED ON RATE-DIVISION MULTIPLE ACCESS NETWORKS METHOD Technical Field The invention introduces speed splitting as a multi-access approach to provide multi-user service. computer for retransmission of wireless networks, especially in 5G and B5G networks, using A method implemented by and configured to perform that method It's about the system. Prior Art Multiple access techniques allow many users to access information such as time, frequency or area on wireless networks. Allows simultaneous orthogonal and non-orthogonal connection to some resources These are approaches that give. Recently, non-orthogonal multiple access (NOMA) and rate division Non-orthogonal approaches such as multiple access (RSMA) are widely used among researchers. It has potential interest for several reasons.

The first of these reasons is to serve multiple users at the same time, such as spectral and energy. To ensure that various efficiencies are achieved. At the same time, multi-user enterprise An interference management mechanism should be implemented to prevent the problem.

The second of these reasons is to serve multiple users simultaneously, system capacity This means an increase in the number of users who can use the resources. is coming.

Finally, effective multiple access allows these resources to be used in a variety of ways, such as energy, bandwidth, time, and space. fundamental to any communication system that plays an active role in achieving their efficiency. It provides effective resource management as its components.

NOMA is one of the most promising radio access techniques in next-generation wireless communications.

NOMA is the current effective standard orthogonal multiple access (OMA) technique. Compared to division multiple access (OFDMA), improved spectrum efficiency, higher a set of desired potential, such as reduced latency and massive connectivity with reliability offers benefits. OFDMA, orthogonal Frequency Division Multiplexing (OFDM), digital It is a multi-user version of modulation technology. Subcarriers to individual users Multiple access is provided in OFDMA by assigning subsets. This is from multiple users It allows simultaneous low data rate transmission.

The basic idea of NOMA is to create orthogonal data using the same sources in terms of time, frequency and field. is to provide service to more than one non-user. NOMA techniques, code space NOMA and power The field can be divided into two main categories: NOMA. Overlay on Transmitter The power field NOMA, based on its coding (SC) and Sequential Interference Cancellation (SIC) at the receivers, It has been considered as a promising multi-access scheme for future mobile networks.

Since the NOMA principle allows multiple users to overlap the same resource, It leads to interference towards such systems. As a result, especially for ultra-dense networks existing resource management and interference mitigation techniques for this new technology needs to be reconsidered due to the inclusion of additional interference.

NOMA has several known disadvantages.

The first of these advantages is that when the number of users belongs to the receiver complexity (i.e. SIC The number of layers) increases and the SIC error propagation increases. Also, K-user 8180 (single input single output) user with the strongest channel for BC (broadcast channel), K-l of all other co-programmed users before accessing its intended message. K-1 SIC layers are needed to decode and remove interference in messages. hears.

One practical approach to address this issue is to group users into smaller groups. by clustering, applying SC-SIC in each group, and dividing user groups through OMA. planning to limit the number of SIC layers in each user. However, this type This approach may cause performance loss and increase latency. Moreover, NOMA has several limitations in multi-antenna networks, for example, multi-antenna NOMA, SIC, It may suffer from a DoF loss due to inefficient use, and multi-antenna NOMA transmitter and can impose significant computational loads on receivers. The initiative's code transmitter as well as the multiple SIC layers required at each user to decode also the interconnection of precoders, user grouping, and decoding orders. As they are combined, they require a joint optimization. Multi-antenna NOMA, user It may be sensitive to distribution. Typically, user channels are available in each user group. is nearly aligned and relatively orthogonal across different user groups. Best suited for overload scenarios. Intergroup interference is the same as in SDMA. Multiple antenna NOMA is vulnerable to CSIT inaccuracies because it is managed in such a way that It may happen.

Space division multiple access (SDMA) is an unprecedented technology for wireless communications. Exploding demand and scarcity of spectrum resources mean multiple antennas at all access points multiple-input multiple-output (MIMO) communications in modern wireless networks by placing motivated its adoption. MIMO is one of the most important and important features for current wireless networks. It has become one of the indispensable technologies and almost all high-speed wireless standards (e.g., 5G New Radio-NR, 4G Long Term Evolution-LTE, It constitutes. SDMA properly handles spatial sources and multi-antenna processing. By using it, it can serve more than one user on the same time-frequency resource and Therefore, it increases SEa. MIMO naturally involves multiple antenna broadcast channels (BC) and multiple It depends on the information-theoretic literature on the access channel (MAC). However, SDMA has only a few Suitable for installed systems and having sufficient transmission antenna SDMA network is a prerequisite for successful enterprise management based on the use of It has some disadvantages such as performance drops significantly when installed. Extreme A common method to handle uploaded settings is to separate users into different groups, is to schedule user groups via OMA and use SDMA in each user group. However, this reduces QoS and increases latency. Second SDMA is sensitive to user distribution (including angles and strengths of user channels), This thus places a more stringent requirement on the programmer. SDMA, programmer users with nearly orthogonal channels and relatively similar channel requires matching it with its powers. Lastly, SDMA is susceptible to CSIT spoofing.

Unlike its good performance in the perfect CSIT setting, SDMA performs poorly when the CSIT is imperfect. cannot achieve maximum DoFs. In fact, its performance is significant in the presence of defective CSIT. is decreasing significantly. This is because SDMA is perfectly designed for CSIT. is to be. A person motivated by perfect CSIT under conditions of imperfect CSIT The application of the frame eliminates residual noise caused by imprecise interference reduction in the transmitter. causes multi-user interference (via imperfect linear precoding).

RSMA, downlink for multiple access frames for multiple antenna systems is a general and strong candidate and includes both SDMA and NOMA as special cases.

RSMA decodes part of the interference and decodes the rest of the interference as noise. It relies on speed division that is linearly pre-coded with the SIC to operate. End At times, RSMA is used in a wide range of network loads (underloaded and overloaded regimes) and in user deployments (diversity of channel directions and channel strengths and channel with attributes of state information) outperforms both SDMA and NOMA has been shown to show. As a result, RSMA combines the two extremes of SDMA and NOMA. It bridges and unites. To partially decode the initiative, users The various messages are divided into common and private parts in the rate partition (RS). common parts are coded and decoded jointly by many users, while private parts It is decoded only by the relevant users. RSMA, a wide range of users SDMA and NOMA in the presence of perfect and imperfect CSI in their distribution and Transmitter (CSIT), from is more spectrally efficient. On the other hand, in enterprise management strategies, large One need is to implement RSMA, or an efficient network compatible beyond 5G (B5G) networks. is to introduce a multiple access approach. Complete decoding of the interference and removal of the interference from noise It is between processing as.

One of the biggest reasons to use RSMA in 5G/6G networks is that multi-user interference Overcoming the flaw in CSIT, where one of the main sources is the flaw in CSIT is the ability. CSIT defects and interference are now easily detected by the precoders in the transmitter. Enterprise management becomes even more difficult in the presence of imperfect CSIT, as it implies that it cannot be managed. is blocked, for example, interference is eliminated because the channel is not known correctly It cannot be removed. Unfortunately, obtaining the correct CSIT involves many inevitable distortions. It is difficult due to its source. This flaw introduces additional multi-user interference and MIMO has become the primary performance bottleneck in their networks. However, such severe multi-user interference both SDMA and multi-antenna NOMA (with multiple user groups) It is considered as noise by the Dealing with this practical limitation of flawed CSIT The classical approach to release is SDMA, which is designed under the assumption of perfect CSIT, and where the precoders for NOMA are tuned to account for imperfect CSIT. necessitated an innovation in the field.

The retransmission technique is an effective way to improve system performance and Packet retransmission is often requested when the packet is found to be faulty.

This scheme, called automatic retransmission request (ARQ), uses extremely low packet It aims to provide an error rate. ARQ's efficiency is reduced by previous (re)transmissions. can be increased by reusing data instead of throwing it away. As Hybrid ARQ (HARQ) This technique, called Tracking Coupling (CC) and Incremental Redundancy (IR), includes. HARQ, LTE system for reliable data transmission with Multiple Input Multiple Output (MIMO) is supported. MIMO combined with HARQ potentially leads to higher reliability A higher throughput package can provide data services.

HARQ retransmissions on the MAC respond more quickly to channel conditions and It increases performance for latency-sensitive applications. HARQ can be adapted. Retransmissions, different encoding rates and backup bits can use. The receiver does not discard erroneous packets, but stores them in its buffer. It stores. All versions are used to improve decoding. HARQ, It does not discard faulty packets. They are stored in the buffer and reused for later retrieval. are combined with the sent packages. Hybrid ARQ with Soft Joining It is said. With Increasing Redundancy, retransmitted packets are associated with the same bits of information, but Each packet carries a different subset of information and parity bits. 8 output paths HARQ process 4 processes run with a delay on both the user side and the base station. HARQ The process length is the same as one subframe (1 ms). User sends data to base station When sent, the base station decodes the data and checks the CRC. Base The station then informs the user after 4 subframes whether an acknowledgment (ACK) or no acknowledgment exists. (NACK) is sent. Depending on the base station response, the user will send new data or will retransmit data. Soft Merging is a method where bad packets are not discarded but are It is an error correction technique where data is stored in the buffer. The basic idea is that 2 or more questions taken with insufficient information The more packets can be combined such that the total signal can be decoded.

Two types of HARQ, follow-joining, also known as type 1 HARQ, and type 2 HARQ, also known as known as increased redundancy. In follow merging, the merging approach data contains error detection bits. and uses forward error correction bits (FEC). FEC on each message before it is sent bits are added. If the channel quality is good, errors are detected and is being corrected. However, if the channel quality is bad, all errors cannot be corrected and the receiver requests retransmission (such as ARQ). FEC is a huge overhead adds. In case of increased redundancy, the merging approach uses data, error detection bits and FEC It uses bits. However, each retransmission produces a different subset of data, a different error. detection subset and a different FEC subset are sent. For example, in the first transmission, A subset of information is sent. Retransmissions, a different data set, error detection and It is done with FEC.

Error control coding or channel coding is very important in modern digital communication systems. It plays a role. A simplified block diagram of a digital communication system is shown in Figure 1. is shown.

Channel coding allows extra bits for future error correction or error detection at the receiver. Negative reduction of noise and interference in the communication channel by including redundancy Information is carried out on data in a way to mitigate its effects. Demodulator's transmitted capacity to restore signals, noise, interference, Doppler shift, multipath fading and etc. are hindered by different channel factors. These factors are demodulation It causes errors and prevents reliable communication. Therefore, a channel The purpose of the encoder is to combat these errors caused by unfavorable channel conditions. is to facilitate a way to do it. Today's error-correcting codes generally have two main They can be classified into categories: (i) block codes and (ii) convolution codes. Both HARQ It can be used by.

More recently, the transmitter has a linear pre-coded rate division (RS) adopted and called rate division multiple access (RSMA) in which receivers use SIC. A general multiple access framework is proposed as shown in Figures 2 and 3. RSMA, initiative widely used area division multiple access (SDMA) and A technique for bridging non-orthogonal multiple access (NOMA) that decodes interference It is seen as [6]. In RSMA, the transmitted signal is divided into a common and private signal, where the common signal is first decoded by all receivers and received using SIC must be subtracted from the signal, then each receiver will filter out unwanted specific signals as noise. It decodes the intended specific signal. The RS idea was first developed by Carleial. In this study, a two-user interference channel model was proposed. Figure 2, users data is divided into two parts, namely public and private, CP 1 and CP 2, respectively. based on transmitter structure where it represents the common part of the data for user 1 and user 2 It represents the RSMA approach. PP 1 and PP 2 refer to user lae and user 2, respectively. It represents the specific part of the data for CP 1 is the common parts of both users. It is a combination. XC is the public stream for both users. XPl and XP2, respectively, user lae and are streams specific to user 2.

ClerckX et al. introduced a rate splitting strategy and RSMA's reliability, spectral and energy benefits in terms of efficiency and reduction of channel state information (CSI) feedback. emphasized. Joudeh and ClerckX between multi-channel multicast groups with RSMA He researched the problem of maximum-minimum justice by communicating BF. Better spectral and energy To achieve efficiency, Mao et al. rate division, non-orthogonal, unicast and multicast He researched multicast strategies. More recently, Yin and ClerckX have used RSMA a lot. applied to a beamed satellite system and BF to ensure maximum-minimum fairness. examined its design. However, due to the uncertainty of wireless channel conditions, error correction The mechanism is not studied and is being investigated for RSMA networks.

Brief Description and Purposes of the Invention The main purpose of the present invention is to prevent errors in rate division multiple access based on retransmission method. propagation, propagation delay, errors due to interference and noise, and especially is to solve the problems of defective channel status information.

The mentioned problems are solved in this invention by using the hybrid automatic repeat request (HARQ) protocol. It is solved by proposing an adaptive/intelligent/awareness retransmission approach. HARQ, Obtaining an effective retransmission scheme for recovering messages with missing packets medium access control (MAC) - layer acknowledgment (ACK) - negative acknowledgment (NACK) feedback It combines the mechanism with channel coding.

The first NACK in response to the second NACK and the common packet in response to the private part are intelligently A convenient HARQ approach to RSMA networks by retransmitting as And the buyer is a In case of the third NACK, the base station will send all data in response.

By proposing this type of protocol, it reduces the retransmission delay in the system, improves reliability and overcomes imperfect channel state information (CSI). It reduces the number of transmission attempts to 3.

The main contributions of the present application to the prior art are as follows; A unique retransmission in which data of several users is mixed and combined approach is introduced.

Minimizing the number of retransmissions up to 3 and reducing the retransmission delay in the system is trying to reduce it. This RSMA approach is called the IR approach used in HARQ. It will provide higher flexibility to divide the data that can be considered.

Increasing the reliability level at the receiver and overcoming defective CSP. More then, greater flexibility in the transmitter and simplifying the receiver structure, because it has in It uses conjunctions to combine things based on what we are. Also, MAC It is compatible with various approaches such as link adaptation and scheduling at the layer 2.

The user equipment has one antenna and will have multiple copies at the receiver. This, this copies Virtual merging (VC) between them will provide a gain in diversity. This By doing so, VC will be made based on the proposed approach. What is the reliability of the system? We can apply any optimization method depending on what we need/want, this flexibility to use several methods of defragmentation based on system requirements It provides.

Finally, users with less acceptable errors are encouraged to increase retransmission. channel gain as well as diversity gain to improve system performance to obtain. However, on the other hand, users who do not want to buy more independent copies can buy They can be used to increase the diversity on the side.

Description of the Forms of the Invention Necessary figures and related explanations for a better understanding of the subject of the invention is given below.

Figure 1. Block diagram of a typical digital communication.

Figure 2. Transmitter model of RSMA in MIMO networks.

Figure 3. Receiver model of RSMA in first-user MIMO networks.

Figure 4. System model of the RSMA network.

Figure 5. Retransmission process of the present invention.

Figure 6. Flow chart for the present invention.

Reference Numbers Reference is made to the parts and components given in the figures for a better understanding of the subject of the invention. is available.

B.S. Base station UE. User equipment PD. private data CD. common data Detailed Description of the Invention The invention introduces speed splitting as a multi-access approach to provide multi-user service. computer for retransmission of wireless networks, especially in 5G and B5G networks, using A method implemented by and configured to perform that method It's about the system.

The system model is preferably designed to serve several users on the network, as shown in Figure 4. At least one base station (BS) that implements the MIMO (multiple input multiple output) approach Contains. Base station (BS) is used to serve multiple users on the network. It uses RSMA. It is also assumed that the user has an antenna. Your mistake is a occurs in the user equipment (UE) and the user equipment (UE) receives information from the base station. (BS) in case it requests retransmission. Defective channel estimation and user in the system Low SNR at the desired receiver due to mobility or pilot contamination The mentioned error occurs due to (signal noise ratio).

Looking at Figure 4; data from the base station (BS) to a user equipment over a network (UE) is sent. The user equipment is a device that can receive data transmitted from the base station (BS). It is a device with a communication unit. Communication unit compatible with wireless and/or wired communications It may happen.

In the present invention, the data is transferred to a common data (CD) (also publicly available) in accordance with the RSMA protocol. It is intended to be divided into two parts: known) and special data (PD). Data, a separator divided by unit (not shown). The disconnector unit is a device or a circuit It has the ability to split electronic data. Private data (PD) is available to all users who have access to the library with this data. can be read, but only by the user who originally wrote the data. can be changed. All users who can access a shared data (CD), data and the library It can be accessed for reading and updating.

Referring to Figures 5 or 6; Firstly, data is transmitted over the network to user equipment (UE). is sent. User equipment (UE), smart device (e.g. mobile phone, tablet) or It can be a computer. The data is examined to determine the level of reliability and The predetermined value is compared with the reliability level.

This determination is made by error correction code (ECC), more specifically forward error correction (FEC). is being carried out. In FEC, the base station (BS) sends the message using an error correction code. It codes unnecessarily. Redundancy means that the receiver cannot occur anywhere in the message. It detects a limited number of errors that may occur and usually detects these errors without retransmitting them. Allows correction. FEC sends a reverse message to the recipient to request retransmission of the data. without the need for a channel, but at the expense of a fixed, higher forward channel bandwidth Provides the ability to correct errors.

If the data is not reliable according to the above steps, the system will specifically perform a check unit (not shown) constitutes a negative confirmation. Negative confirmation to base station is the response to be sent. This negative confirmation means that the common data (CD) or private data (PD) wants it to be forwarded. In the preferred embodiment of the present invention, from the first determination The controller then issues a negative acknowledgment requesting retransmission of the common data (CD). is sending.

The controller is an integral part of the network or user equipment (UE). can be provided. The control unit can determine the reliability level of the data and can compare the level of reliability with a predetermined value and determine the reliability of the data. If the level is lower than the predetermined value, the data will be retransmitted. is a device or circuit capable of producing a negative confirmation of; negative confirmation here, base is the response to make the station send its private data or public data.

After the first negative confirmation is received, this confirmation is sent to the base station (BS) and It sends the common data (CD) of the data packet in response to this base station.

Common data is examined to determine the level of reliability and the value is previously determined. The determined value is compared with the reliability level. This determination is error correcting code (ECC), more specifically forward error correction (FEC). data, second If it is not reliable according to the determination step, the system, especially a control unit It constitutes another negative confirmation. In the preferred embodiment of the present invention, The second acknowledgment is a negative acknowledgment that requests retransmission of private data (PD).

In response to the second negative acknowledgment, the base station (BS) sends private data (PD) and this The specific data is examined to determine the level of reliability and the value is previously The determined value is compared with the reliability level. This determination is error correcting code (ECC), more specifically forward error correction (FEC).

If, based on the examination, the desired level of reliability is not yet achieved, the control The third negative approval is created by the unit. The third negative confirmation is that all data It is the confirmation that requests retransmission.

In the present invention, any point control unit can be used where the desired level of reliability is achieved. where this confirmation is based on the combination of common data (CD) and private data (PD). It is a response/command to merge. More precisely, data or common data After determining the reliability level of (CD) or private data (PD), the desired reliability If the level is achieved, approval is created.

The joining step is performed by a combining unit (not shown).

A combining unit is a device or circuit that can combine divided electronic data.

In the preferred embodiment of the invention, the user equipment (UE) has an antenna. Again By transmitting, multiple copies of the same data are available at the receiver. This means the channel is not static. In this case, it provides a diversity gain as well as a channel gain. As a result, this Virtual merge (VC) will be performed between the copies. Also, as in traditional schemas It is not necessary to use a specific join type at the receiver, such as Here, the optimum at the receiver defragmentation may be based on system requirements, MMSE, selective defragmentation or system It may be a new design based on what the needs are.

Claims (13)

STEMS 1. Network usage is a computer-implemented retransmission method for rate division multiple access, Sending a data packet to a network by a base station, Determining the reliability level of the data, Sending a negative acknowledgment for retransmission of the data if the reliability level of the data is lower than the predetermined value, Dividing the data into a private data (PD) and a common data (CD), Sending the common data by a base station (BS) in response to a negative confirmation, Determining the reliability level of the received common data (CD), The reliability level of the data being lower than the predetermined value. It is characterized by sending a negative acknowledgment for the retransmission of data, sending private data (PD) by a base station in response to a negative acknowledgment, determining the reliability level of the received private data (PD). . It is a method according to claim 1, characterized in that it further includes the step of transmitting all data to the network by the base station in case the reliability level of the private data data is lower than the predetermined value. . It is a method according to claim 1, characterized in that it further includes the step of merging private data (PD) and common data (CD) in case the reliability level of the data is higher than the predetermined value. . It is a method according to claim 3, characterized in that it includes the step of sending a separate confirmation to the network by the base station to combine the private data (PD) and common data (CD) if the reliability level of the data is higher than the predetermined value. . It is a method according to claim 1 and is characterized by determining the error and reliability level of the data with the error correction code. It is a method according to claim 1 and is characterized by determining the error and reliability level of the data by forward error correction. It is a system that uses rate division multiple access for retransmission of data in the network. A base station (BS) and a user equipment (UE) configured to transmit data to and receive data from each other. It divides the data into a private data (PD) and a common data (CD). A splitter unit configured to split private data (PD) and common data (CD) A combiner unit configured to combine private data (PD) and common data (CD) To determine the confidence level of the data and compare the confidence level of the data with a predetermined value, and if the confidence level of the data is lower than the predetermined value, the data is re A system according to claim 7, characterized in that the control unit is configured to generate a negative acknowledgment which is a response to enable a base station for transmission to send private data or public data, wherein the control unit is configured to cause the base station (BS) to send all data. It is characterized by being structured to generate negative confirmation, which is a response to . A system according to claim 7, characterized in that the control unit is configured to generate a response response to combine the private data (PD) and the common data (CD) if the confidence level of the data is higher than the predetermined value. A system according to claim 7, characterized in that the control unit is configured to determine the error and reliability level of the data with the error correction code. 11. A system according to claim 7, characterized in that the control unit is configured to determine the error and reliability level of the data by means of forward error correction. 12. A system according to claim 7, characterized in that the disconnector is integrated with the control unit. 13. A system according to claim 7, characterized in that the combiner is integrated with the control unit.