KR102650862B1 - How to transmit a signal, how to receive a signal, transmitter and receiver - Google Patents

Abstract

The present application provides a signal transmission method, which includes transmitting, by a transmitter, link grouping setting information, wherein the link grouping setting information is included in each group after dividing the link into at least two groups. The step of transmitting, information of a link; layering, by the transmitter, the data flow to be transmitted according to the grouping of links; performing, by a transmitter, spatial modulation on the layered data flow; performing, by a transmitter, multi-carrier modulation on the spatially modulated signal; and transmitting, by the transmitter, the multi-carrier modulated signal. The present application further provides a signal receiving method, transmitter, and receiver. This application utilizes the features of the spatial modulation system to provide different levels of protection for different data flows, so that users in different channel conditions can obtain different quality of service.

Description

How to transmit a signal, how to receive a signal, transmitter and receiver

This application relates to the field of wireless communication technology, and in particular to methods of transmitting signals, methods of receiving signals, transmitters and receivers.

The rapid development of the information and communication industry, especially the increasing demand for mobile Internet and IoT (Internet of Things), brings unprecedented challenges to future mobile communication technology. According to ITU-R M. (IMT.BEYOND 2020.TRAFFIC) published by the International Telecommunication Union (ITU), by 2020, mobile service traffic will increase almost 1,000 times compared to 2010 (4G era), and user device connections The number will also exceed 17 billion, and the large number of IoT devices will gradually expand into mobile communication networks, and the number of connected devices can be expected to grow even more. In response to these unprecedented challenges, the telecommunications industry and academia have begun extensive research on fifth generation mobile communications technology (5G) to prepare for 2020. Currently, at ITU-R M. [IMT.VISION] from ITU, the framework and overall goals of future 5G were discussed, where 5G's demand outlook, application scenarios and various important performance indicators were explained in detail. In terms of the new demands of 5G, ITU-R M. [IMT.FUTURE TECHNOLOGY TRENDS] from ITU provides information related to 5G technology trends, which include significant improvements in system throughput, consistency of user experience, IoT, and latency. , is intended to address critical issues such as energy efficiency, cost, network flexibility, and scalability to support new services and flexible spectrum utilization.

Multiple-input multiple-output (MIMO) technology is an important technology for improving system spectral efficiency. As MIMO technology can effectively improve the system data rate and improve system link stability, it is widely used in the fields of broadcast audio and video, as well as 3rd Generation Partnership Project (3GPP), European Digital Video Broadcasting (DVB), and IEEE802. 16 It has also been widely used in civil communication systems such as the Long Term Evolution (LTE) system corresponding to E-UTRA (Evolved Universal Terrestrial Radio Access), which was formalized by WiMAX (Worldwide Interoperability for Microwave Access). By forming a communication link between different antennas on the transmitting and receiving sides, MIMO technology can provide spatial diversity gain and spatial multiplexing gain to the system. By transmitting the same data on different links, MIMO technology can improve the reliability of data transmission and achieve diversity gain; By transmitting different data on different links, MIMO technology can improve system spectral efficiency without increasing transmission bandwidth, thereby improving transmission data rate. By using channel state information on the transmitting side, MIMO technology can further improve the spectral efficiency of the entire system by serving multiple users with the same time-frequency resources along with precoding. Currently, MIMO technology is a core technology and can well support 4G Mobile Broadband (MBB) service requirements. In 5G, existing MIMO technologies will find it difficult to meet significantly improved data rates as the demands on spectral efficiency, energy efficiency, and data rates will further improve. Therefore, evolved MIMO technology, i.e. massive MIMO technology, has gained widespread attention from academia and industry. By deploying antennas far more than the number of users on the transmitting side, massive MIMO technology can achieve more array processing gain (finer beams) while also gaining more spatial degrees of freedom, and with simple linear operation, it can connect users to each other. They are fully distinguishable, and thus spectral efficiency and energy efficiency can be further improved. However, in real application scenarios, several problems have arisen not only with MIMO technology but also with large-scale MIMO technology. For example, 1. Whether MIMO technology is effective or reliable depends on whether accurate channel state information can be obtained at the transmitting side. If the channel state information at the transmitting side is not sufficiently accurate, a significant reduction in system gain will result. Current MIMO technology relies on channel estimation based on reference signals and feedback. However, as the number of antennas increases, the overhead associated with reference signals and feedback will severely reduce system spectral efficiency. 2. The requirements for synchronization between antennas are strict. 3. Inter-channel interference needs to be handled at the receiving end. 4. Although multi-user MIMO can improve the overall spectral efficiency of a cell, it does not help improve single-user spectral efficiency.

As a branch of MIMO technology, Spatial Modulation (SM) has become widely popular in academia in recent years. SM technology uses a portion of the information bits to select the transmitting antenna, with only one antenna for each transmission. By using the antenna index as an additional carrier for transmitting information, a three-dimensional constellation is constructed based on the normal two-dimensional constellation, resulting in higher spectral efficiency than a single antenna system. Meanwhile, SM technology further solves some problems of conventional MIMO technology. For example, since each transmission uses only a single antenna, SM technology eliminates the need to perform complex inter-antenna synchronization and cancellation of inter-link interference at the receiving end, simplifying the process at the receiving end; SM technology can improve single-user spectral efficiency and is therefore more suitable for some scenarios where there is a need to improve single-user data rates; SM technology does not require precoding on the transmitting side, so there is no need for feedback on the receiving side; The transmitting side only needs one RF link, greatly reducing the overhead on the transmitting side. SM technology based on multiple carriers loses the advantages of a single RF link, but the allocation of time-frequency two-dimensional resources provides a higher degree of freedom for the system and also better robustness to frequency-selective fading caused by multipath. has

The benefits of SM technology are becoming widespread in communications research. The characteristic of not requiring channel feedback and having no requirements on the number of antennas at the receiving end makes it particularly suitable for broadcasting data or transmitting data in open loop mode. In order to expand the application of spatial modulation technology in 5G and utilize the advantages of spatial modulation technology, it is necessary to deeply explore its characteristics and improve its methods in different application scenarios.

The technical problem to be solved by the present invention is that cellular systems cannot provide differentiated services to users under different channel conditions during transmission of broadcast data. To this end, the present application provides a signal transmission method, a reception method, a transmitter and a receiver, which take advantage of the features of the spatial modulation system to provide different levels of protection for different data flows, so that users in different channel conditions can achieve different levels of quality. Make sure you can receive services.

The present invention provides a method for transmitting a signal, the method comprising:

Transmitting, by a transmitter, link grouping setting information, wherein the link grouping setting information is information on links included in each group after dividing links into at least two groups;

layering, by the transmitter, the data flow to be transmitted according to the grouping of links;

performing, by a transmitter, spatial modulation on the layered data flow;

performing, by a transmitter, multi-carrier modulation on the spatially modulated signal; and

and transmitting, by a transmitter, a multi-carrier modulated signal.

Preferably, the step of dividing the links into at least two groups comprises: dividing all available links into at least two groups, wherein the created groups are groups of a first layer; further dividing each of the first layer groups into at least two groups, wherein the created group is a second layer group; and by this analogy, performing division until each group contains only one link or the setting requirements of the link grouping are met.

Preferably, layering, by the transmitter, the data flow to be transmitted according to the grouping of links comprises: transmitting basic data using the grouping of the first layer, and different from the first layer based on the previous layer. Transmitting auxiliary data using each group of the hierarchy; The auxiliary data includes at least one of extended data based on basic data, redundant information of data of the previous layer, and a combination of the extended data and redundant information.

Preferably, the criterion for dividing links into groups is to assign links with a correlation index greater than a set threshold to one group.

Preferably, the method further comprises estimating, by the transmitter, a correlation index between links according to information from the receiver, thereby dynamically adjusting the number of links and the grouping of links; The information from the receiver includes channel state information fed back from the receiver and/or a sounding reference signal transmitted by the receiver via an uplink channel to the transmitter.

Preferably, the method further includes assigning users with the same link grouping setting information to one group, and performing a broadcast service on the same time-frequency resource for users in the same group.

Preferably, the method further comprises, after preprocessing the spatially modulated signal, performing multi-carrier modulation and transmission.

Preferably, the preprocessing step includes performing power adjustment on the link and/or phase adjustment on the link.

Advantageously, performing power adjustment on a link comprises: adjusting the average transmit power of each of the groups in the first layer such that each of the groups has a different average transmit power, while keeping the transmit power constant; adjusting the average transmit power of each of the groups in the second layer such that each of the groups in the second layer can have a different average transmit power, while keeping the average transmit power of each of the groups in the first layer constant. ; and by this analogy, performing the adjustment until the adjustment of each average transmit power of the group of the lowest layer is completed.

Preferably, the criterion for adjusting the average transmission power of the group in each layer is that the power adjustment amount of the layer is not more than the power adjustment amount of the previous layer.

Preferably, the step of performing phase adjustment on links comprises randomly selecting a rotation phase for each link of a group of the lowest layer, wherein the intervals of each rotation phase of links belonging to different groups do not intersect. and selecting adjacent rotational phase intervals for each link of a group belonging to the same group in the previous layer.

Preferably, it includes using constellation point symbols of spatial modulation to transmit data or other auxiliary or redundant information at the lowest layer.

Preferably, the method further comprises the step of transmitting, by the transmitter, a reference signal according to the grouping of links.

Preferably, the step of transmitting, by the transmitter, the reference signal according to the grouping of links comprises: allowing, by the transmitter, the same time-frequency resources for links belonging to the same group to estimate the equivalent channel coefficient of the corresponding group; and transmitting the same reference signal sequence using.

Preferably, when multi-carrier modulation and transmission are performed after preprocessing the spatially modulated signal, the method further includes performing the preprocessing on the reference signal before transmitting the reference signal.

Preferably, the method further comprises dividing the layered data in each of the layers into blocks, and adding an independent cyclic redundancy check (CRC) code for the data of each layer in each block of data. Includes.

Preferably, the transmitter transmits the link number information and link grouping setting information in at least one of a physical broadcast channel, a physical downlink control channel, and a physical downlink shared channel.

Preferably, the transmitter transmits on a physical broadcast channel, a physical downlink control channel, or a physical downlink shared channel to which an additional field is added, and the additional field indicates link number information and link grouping setting information.

Preferably, the transmitter transmits link number information using a CRC check mask of a physical broadcast channel, each of the transmission modes of the physical broadcast channel corresponds to at least two CRC check masks, and each CRC check mask is Corresponds to one type of information about the number of links; The transmission modes of the physical broadcast channel include single antenna port transmission mode, dual antenna port transmission diversity mode and four antenna port transmission diversity mode;

The transmitter transmits through a physical broadcast channel, a physical downlink control channel, or a physical downlink shared channel to which an additional field is added, and the additional field indicates link grouping configuration information.

The present application further provides a transmitter, the transmitter comprising:

A setting module that transmits link grouping setting information, wherein the link grouping setting information is information about links included in each group after dividing links into at least two groups;

a data layering module that layers data flows to be transmitted according to groupings of links;

a spatial modulation module that performs spatial modulation on the layered data flow;

a multi-carrier modulation module that performs multi-carrier modulation on a spatially modulated signal; and

It includes a transmission module that transmits a multi-carrier modulated signal.

The present application also provides a method of receiving signals. The method is:

Receiving, by a receiver, link grouping setting information;

Obtaining, by a receiver, information on the grouping and links of links included in each group according to the link grouping setting information; and

and performing, by the receiver, layered detection on the received data according to the grouping of links.

Preferably, performing layered detection on data received according to grouping of links, by the receiver, comprises:

Detecting, by the receiver, data transmitted from all layers according to channel state information of each link, and determining the number of layers to be maintained according to setting criteria; The setting criteria includes comparing an estimated signal-to-noise ratio of detected data from each layer with a preset signal-to-noise ratio threshold, and, if higher than the signal-to-noise ratio threshold, retaining data in the corresponding layer. and performing subsequent processing, otherwise not performing subsequent processing; or the setting criteria includes determining, by the transmitter, independently for each layer of data, whether to retain the data of the corresponding layer for each receiver depending on whether a CRC check added by the transmitter passes. .

Preferably, the method includes detecting data of each layer layer by layer according to the channel state information of each group, and adjusting the estimated signal-to-noise ratio of the data detected from each layer to a preset signal-to-noise ratio threshold and Comparing, if higher than the signal-to-noise ratio threshold, performing subsequent detection of data of the next layer, otherwise terminating detection.

Preferably, the method further comprises receiving, by the receiver, a reference signal according to a grouping of links, and performing channel estimation.

The present application further provides a receiver, the receiver comprising:

a configuration information receiving module that receives link grouping configuration information;

a grouping acknowledgment module that acquires grouping and link information of links included in each group according to the link grouping setting information;

It includes a detection module that performs layered detection on the received data according to the grouping of links.

The present disclosure also provides a signal transmission method based on multi-carrier spatial modulation. These methods are:

A transmitting device determining a preprocessing fundamental matrix and expanding the preprocessing fundamental matrix to obtain an expanded preprocessing matrix;

A transmitting device preprocessing a first reference signal with a preprocessing basic matrix and transmitting the preprocessed first reference signal to a receiving device; and

A transmitting device performs symbol mapping and spatial modulation on a bit stream to be transmitted, preprocesses symbols obtained after spatial modulation with an extended preprocessing matrix, and transmits the preprocessed symbols to a receiving device after multi-carrier modulation. .

In one embodiment, determining the preprocessing fundamental matrix includes calculating the preprocessing fundamental matrix according to channel state information, using a predefined preprocessing fundamental matrix, or using a predefined code according to feedback from the receiving device. It includes at least one step of selecting a preprocessing basis matrix from the book.

In one embodiment, calculating the preprocessing fundamental matrix according to the channel state information includes calculating the preprocessing fundamental matrix according to the channel coefficient matrix using a precoding algorithm; The precoding algorithm includes at least one of a matched filter algorithm, a zero-forcing algorithm, and a least mean square error precoding algorithm.

In one embodiment, the channel coefficient matrix includes equivalent frequency-domain channel coefficients consisting of multi-carrier modulation, an actual physical channel between a transmitting device and a receiving device, and multi-carrier demodulation.

In one embodiment, extending the preprocessing basis matrix to obtain an expanded preprocessing matrix includes:

performing a linear combination of the columns of the preprocessing base matrix to obtain the columns of the expanded preprocessing matrix;

performing a phase rotation on the columns of the preprocessing basic matrix to obtain columns of the extended preprocessing matrix, wherein the rotated phases of different elements of each column are the same or different; and

It includes any one or any combination of the steps of multiplying the columns of the preprocessing base matrix by a power allocation factor to obtain the columns of the expanded preprocessing matrix.

In one embodiment, the number of rows of the preprocessing fundamental matrix is equal to the number of transmit antennas, and the number of columns of the preprocessing fundamental matrix is the number of channel state information fed back by the receiving device and the number of available reference signals or used to transmit the reference signal. It is decided by the transmitting device according to the amount of resources available.

In one embodiment, the number of rows of the extended preprocessing matrix is equal to the number of rows of the preprocessing elementary matrix, and the number of columns of the extended preprocessing matrix is greater than or equal to the number of columns of the preprocessing elementary matrix.

In one embodiment, the method includes:

It further includes the step of the transmitting device determining the number of columns of the extended preprocessing matrix according to information fed back by the receiving device.

In one embodiment, the method includes:

It further includes preprocessing the second reference signal by the transmitting device with an extended preprocessing matrix, and transmitting the preprocessed second reference signal to the receiving device.

In one embodiment, the first reference signal is used to estimate the basic equivalent channel and the second reference signal is used to correct the estimate of the extended equivalent channel.

In one embodiment, the basic equivalent channel consists of a preprocessing fundamental matrix, multi-carrier modulation, actual physical channel, and multi-carrier demodulation.

In one embodiment, the method includes:

It further includes the step of adjusting the insertion density of the second reference signal by the transmitting device according to the channel state information fed back by the receiving device, wherein the adjusting step includes selecting the transmitting device not to insert the second signal, preprocessing It includes at least one of selecting to insert at a density lower than the number of columns of the matrix, or selecting to insert at a density equal to the number of columns of the preprocessing matrix.

The present disclosure also provides a transmission device comprising a first preprocessing basic matrix calculation module, a first preprocessing matrix expansion module, a first reference signal transmission module, and a first data transmission module, wherein:

The first pre-processing fundamental matrix calculation module is set to determine the pre-processing fundamental matrix;

The first preprocessing matrix expansion module is configured to expand the preprocessing basic matrix to obtain an expanded preprocessing matrix;

The first reference signal transmission module is configured to perform preprocessing on the first reference signal with a preprocessing basic matrix and transmit the preprocessed first reference signal to the receiving device;

The first data transmission module performs symbol mapping and spatial modulation on the bit stream to be transmitted, performs preprocessing on the symbols obtained after spatial modulation with an extended preprocessing matrix, and multicarrier modulates the preprocessed symbols to a receiving device. It is set to transmit to .

The present disclosure also provides a method of signal transmission based on multi-carrier spatial modulation in a multi-user system, the method comprising:

A transmitting device selecting a preprocessing basic matrix for each terminal according to channel state information, and expanding the preprocessing basic matrix of each terminal to obtain a corresponding expanded preprocessing matrix;

A transmitting device performs preprocessing on a reference signal with each preprocessing basic matrix, and transmits the preprocessed reference signal to the corresponding terminal, wherein the reference signal transmitted to the different terminal uses orthogonal resources. ;

A transmitting device performing symbol mapping and spatial modulation on the bit streams of each terminal, respectively, and performing preprocessing on symbols obtained after spatial modulation of each terminal with a corresponding extended preprocessing matrix; and

It includes a step where the transmitting device combines the preprocessed symbols of each terminal and transmits the combined symbol after multi-carrier modulation.

In one embodiment, the terminals are receiving devices that are simultaneously serviced and use the same time-frequency resources.

In one embodiment, the step of the transmitting device selecting a preprocessing basic matrix for each terminal according to the channel state information includes: the transmitting device calculating the preprocessing basic matrix according to the channel coefficient matrix, or the channel fed back by the terminal. It includes at least one step of selecting a preprocessing basic matrix from a predefined code book according to state information.

In one embodiment, the channel coefficient matrix includes equivalent frequency-domain channel coefficients consisting of multi-carrier modulation, actual physical channels between the transmitting device and all terminals, and multi-carrier demodulation of each terminal.

In one embodiment, combining includes adding symbols to be transmitted on the same link.

The present disclosure is also applicable to a multi-user system based on multi-carrier spatial modulation, and includes a transmission device comprising a second pre-processing basic matrix calculation module, a second pre-processing matrix expansion module, a second reference signal transmission module and a second data transmission module. provides; here,

The second preprocessing basic matrix calculation module is configured to select a preprocessing basic matrix for each terminal according to the channel state information;

the second preprocessing matrix expansion module is configured to expand the preprocessing basic matrix of each terminal to obtain a corresponding expanded preprocessing matrix;

The second reference signal transmission module is configured to perform preprocessing on the reference signal with each preprocessing basic matrix and transmit the preprocessed reference signal to the corresponding terminal, and the reference signal transmitted to the different terminal uses orthogonal resources;

The second data transmission module performs symbol mapping and spatial modulation on the bit streams of each terminal, performs preprocessing on the symbols obtained after spatial modulation with the corresponding extended preprocessing matrix, and transmits the preprocessed symbols of the terminal. By combining, the combined symbol is set to be transmitted after multi-carrier modulation.

The present disclosure also provides a method of receiving a signal based on multi-carrier spatial modulation, the method comprising:

A receiving device receiving a first reference signal and estimating a basic equivalent channel based on the first reference signal;

a receiving device extending the estimate of the basic equivalent channel using a method consistent with the method used by the transmitting device to expand the preprocessing basic matrix to obtain an estimate of the expanded equivalent channel; and

A receiving device receives data and demodulates the received data according to an estimate of the extended equivalent channel to obtain the original data.

In one embodiment, the method includes:

The method further includes receiving, by the receiving device, a second reference signal and correcting the estimate of the extended equivalent channel according to the second reference signal.

The present disclosure also provides a receiving device including a receiving module, a basic equivalent channel estimation module, an extended equivalent channel estimation module and a demodulation module; here,

The receiving module is configured to receive a first reference signal and data;

The basic equivalent channel estimation module is set to estimate the basic equivalent channel based on the first reference signal;

the extended equivalent channel estimation module is configured to expand the basic equivalent channel using a method consistent with the method used by the transmitting device to expand the preprocessing basic matrix to obtain an estimate of the expanded equivalent channel;

The demodulation module is set to demodulate data according to an estimate of the extended equivalent channel to obtain the original data.

In one embodiment, the receiving module is further configured to receive a second reference signal;

The extended equivalent channel estimation module is further configured to correct the estimate of the extended equivalent channel according to the second reference signal.

The present invention provides a method and device for using multiple antennas to provide layered services for users receiving broadcast services. By adopting the present invention, users with better channel conditions can receive more data or receive more reliable data, and users with poor channel conditions can also obtain basic service, so that the channel conditions with the poorest service quality It is possible to avoid the problems of the conventional broadcast service that is determined by the number of users, and thus to provide differentiated services to users with different channel conditions.

Meanwhile, by performing spatial modulation through preprocessing, multi-carrier modulation, equivalent channels consisting of actual physical channels and multi-carrier demodulation, link reliability can be effectively increased, and the ability of the multi-carrier spatial modulation system for fading or correlated channels. This improves.

Figure 1 is a block diagram of an existing multi-carrier spatial modulation system.
Figure 2 is a schematic diagram of an existing MBSFN system.
Figure 3 is a schematic diagram of one possible way of link grouping in the first embodiment of the present invention.
Figure 4 is a schematic diagram of bit grouping in the first embodiment of the present invention.
Figure 5 is a schematic diagram comparing the bit error rate performance of different groups when four receiving links are equipped on the receiving side in the first embodiment of the present invention.
Figure 6 is a schematic diagram comparing the bit error rate performance of different groups when two links are equipped on the receiving side in the first embodiment of the present invention.
Figure 7 is a schematic diagram comparing the bit error rate performance of different groups in the first embodiment of the present invention when two links are equipped on the receiving side and there is high correlation between the links.
Figure 8 is a schematic diagram of the data layering method in the first embodiment of the present invention.
Figure 9 is a schematic diagram of power allocation between links in a second embodiment of the present invention.
Figure 10 is a schematic diagram of the operational flow of the multi-carrier spatial modulation technique supporting layered transmission used in the third embodiment of the present invention.
Figure 11 is a schematic diagram of a method for transmitting link number information and link grouping setting information in the third embodiment of the present invention.
Figure 12 is a schematic diagram of carrying link number information by the method of a CRC mask in the third embodiment of the present invention.
Figure 13 is an exemplary diagram of grouped transmission of RS in the fourth embodiment of the present invention.
Figure 14 is a schematic diagram of resource allocation of grouped transmissions in the fourth embodiment of the present invention.
Figure 15 is a schematic diagram of grouping users in the fifth embodiment of the present invention.
Figure 16 is a schematic diagram of the process of grouping users in the fifth embodiment of the present invention.
Figure 17 is a schematic diagram of a multi-carrier spatial modulation technology process based on layered transmission in the fifth embodiment of the present invention.
Figure 18 is a schematic diagram of the configuration of one preferred transmitter of the present invention.
Figure 19 is a schematic diagram of the configuration of one preferred receiver of the present invention.
Figure 20 is a schematic diagram showing a preprocessing-based multi-carrier spatial modulation system according to the first embodiment of the present disclosure.
Figure 21 is a flowchart showing a signal processing procedure in TDD mode according to the first embodiment of the present disclosure.
Figure 22 is a diagram comparing the bit error rate performance of the conventional solution and the proposed preprocessing-based solution with a spectral efficiency of 6bps/Hz according to the second embodiment of the present disclosure.
Figure 23 is a diagram comparing the bit error rate performance of the conventional solution and the proposed preprocessing-based solution with a spectral efficiency of 4bps/Hz according to the second embodiment of the present disclosure.
Figure 24 is a schematic diagram showing a multi-user MIMO system based on preprocessed spatial modulation according to a third embodiment of the present disclosure.
Figure 25 is a flowchart showing a signal processing procedure based on a fixed preprocessing fundamental matrix according to the fourth embodiment of the present disclosure.
Figure 26 is a schematic diagram showing a comparison of bit error rate performance of different solutions with a spectral efficiency of 6bps/Hz according to the fourth embodiment of the present disclosure.
Figure 27 is a schematic diagram showing a comparison of bit error rate performance of different solutions with a spectral efficiency of 4bps/Hz according to the fourth embodiment of the present disclosure.
Figure 28 is a schematic diagram showing the generation of a preprocessing matrix with adaptive parameter selection according to a fifth embodiment of the present disclosure.
Figure 29 is a flowchart showing a reference signal insertion and channel estimation procedure according to the fifth embodiment of the present disclosure.
Figure 30 is a schematic diagram showing a comparison between a constellation with preprocessing and a constellation without preprocessing at the receiving end according to the sixth embodiment of the present disclosure.
Figure 31 is a schematic diagram showing a comparison of bit error rate performance of the conventional solution and the proposed solution when the transmitter has four antennas according to the sixth embodiment of the present disclosure.
Figure 32 is a schematic diagram showing a comparison between a constellation with preprocessing and a constellation without preprocessing at the receiving end according to the sixth embodiment of the present disclosure.
Figure 33 is a schematic diagram showing a comparison of bit error rate performance of the conventional solution and the proposed solution when the transmitter has 16 antennas according to the sixth embodiment of the present disclosure.
Figure 34 is a schematic diagram showing the structure of a transmission device according to an embodiment of the present disclosure.
Figure 35 is a schematic diagram showing another structure of a transmission device according to an embodiment of the present disclosure.
Figure 36 is a schematic diagram showing the structure of a receiving device according to an embodiment of the present disclosure.

In order to make the purpose, technical solutions and advantages of the present application clearer, reference is next made to the attached drawings, examples are illustrated, and the description of the present application is made more detailed.

Spatial modulation techniques use antenna indices to transmit data as an additional carrier for information. Compared to a single antenna system, it can achieve higher spectral efficiency with the same bandwidth. However, compared to existing multi-antenna systems, spatial modulation technology has the following advantages. 1. Since only one of multiple antennas is used for any data transmission, synchronization between antennas is no longer required at the receiving end; 2. The use of only one antenna cannot cause inter-link interference, so the receiving side does not need an equalization algorithm with higher complexity to eliminate inter-link interference; 3. The need for only a few RF channels can significantly reduce the problem of high energy consumption caused by multiple RF channels, that is, spatial modulation is a system with high energy efficiency; 4. The spatial modulation system can still work when the number of antennas at the transmitting side is greater than the number of receiving antennas. Moreover, spatial modulation makes system parameters more flexible, since the same spectral efficiency can be realized by a combination of different numbers of antennas and modulation methods. Spatial modulation systems combined with multi-carrier technologies such as Orthogonal Frequency Division Multiplexing (OFDM) perform spatial modulation on frequency domain equivalent multi-antenna channels, including multi-carrier modulation, real physical channels, and multi-carrier demodulation. do. Although you lose the advantage of having fewer RF channels, you gain greater freedom, especially on issues such as resource allocation and pilot frequency allocation, and are also more compatible with standards.

A block diagram of the multi-carrier spatial modulation technique is shown in the dashed box on the left of Figure 1, where the number of antennas at the transmitting side is set to N, and the modulation order used is Q=2 ^B , where B is mapped to a symbol. It is the number of bits. Its basic process is as follows: in the transmitted data flow, a number of log ₂ (NQ)=log ₂ (N)+B bits exist as one group, and the first log ₂ (N) bit is Determines the data flow index used, and the following B bits are mapped to one QAM symbol. Taking N = 2, B = 2 as an example, the mapping relationship from spatial modulation bits to symbols is shown in Table 1, where antenna index represents the current antenna index for the transmitted data. In the sequence of transmitted bits, the first bit is used to determine the antenna index and the next two bits are used to determine the symbol to be transmitted. After the spatially modulated symbols are obtained, Inverse Fast Fourier Transform (IFFT) is performed to obtain the data flows in which all N data flows are transmitted on the N transmit antennas.

[Table 1]

Table 1: Bit-to-symbol mapping relationships

A block diagram of the receiving side of the spatial modulation technology employing OFDM technology is shown in Figure 1 as a dotted box on the right, and M antennas are mounted on the receiving side. Upon receiving the received signal, Fast Fourier Transform (FFT) on the receiving side may be performed on the data flow of each receiving antenna to obtain a frequency domain signal. Assuming that the frequency domain equivalent channel matrix including the transmitting side IFFT, the actual physical channel, and the receiving side FFT is H∈C ^MxN , each channel model can be written as follows:

y = Hx+n

Here, H is the frequency domain equivalent channel matrix expressed as ^an M x N dimensional complex matrix, M is the number of equivalent reception links, N is the number of equivalent transmission links, C = e _i s _j ∈C ^Nx1 is the transmitted spatial modulation symbol vector, and n∈C ^Mx1 is the noise vector. Vector e _i =[0,...,0,1,0,...,0] ^T ∈C Only the i element of ^Nx1 is 1, the rest are 0, which means that only the i antenna is It is used for data transmission, and [] ^T represents the transpose of the vector. The symbol s _j is a symbol selected from a symbol set of constellation mapping, for example, Quadrature Amplitude Modulation (QAM), Pulse Amplitude Modulation (PAM), or Phase Shift Keying (PSK), depending on the transmission bit. Therefore, the received symbol can be abbreviated as:

y = h _i s _j + n

Here, h _i ∈C ^Mx1 is the ith column of matrix H.

On the receiving side, the maximum likelihood detection algorithm below is used to detect transmitted symbols:

의 추정과 수신 심볼

의 추정치를 획득한 후, 비트 대 심볼 매핑 기준에 따라 송신 비트 흐름의 추정 값이 획득될 수 있다.Transmit antenna index

Estimation and reception of symbols

After obtaining the estimate of , an estimated value of the transmission bit flow can be obtained according to the bit-to-symbol mapping criteria.

In addition to the spatial modulation systems described above in which there is only one data transmission link at a time, the Generalized Spatial Modulation (GSM) system activates a subset of all links on each transmission and uses the indices of the subsets as carriers. transmit information, but different links transmit the same data to improve system reliability; Different data can be transmitted to improve the data rate of the system. This is considered a form of spatial modulation in this disclosure.

Prior art publications [Bit Error Probability of SM-MIMO Over Generalized Fading Channels] and simulation results show that, compared to conventional open loop MIMO systems (e.g., Space Frequency Block Coding (SFBC) or V-BLAST systems), We show that a multi-carrier spatial modulation system can better navigate the receive diversity provided by the receive antennas, thereby achieving much better performance than conventional open-loop systems for users equipped with multiple receive antennas. The nature of spatial modulation systems, which do not require channel feedback, makes these techniques particularly suitable for broadcast channels, such as the Physical Multicast Channel (PMCH) that provides Multi-media Broadcast/Multicast Service (MBMS).

In existing LTE-A, MBMS service is provided in the form of MBSFN (Multimedia Broadcast Single Frequency Network), as shown in FIG. 2. In the figure, multiple base stations simultaneously transmit the same broadcast information at the same frequency and use signals from different base stations as multipath components, which achieves a higher signal-interference plus noise ratio (SINR) than a single cell system. Therefore, it is very suitable not only for moving users but also for users at the edge of the cell.

In addition to the difficulty of using the transmitter's channel state information in the broadcast channel, the characteristics of diversity of users served simultaneously make it difficult to apply the typical MIMO technology, making it difficult to apply the existing standard PMCH (physical layer multicast channel) Transmits using only a single antenna. In this case, multi-carrier spatial modulation techniques that do not require channel state information feedback can not only utilize multiple antennas on the base station side but also provide higher data rates than transmission from a single antenna. By combining MBSFN, higher reliability can be achieved than single cell multi-carrier spatial modulation. Therefore, there is a high possibility of applying spatial modulation technology to PMCH.

In current MBMS transmission, transmission modes can only be designed for the worst channel, making it difficult for users to achieve better data rates under good channel conditions, limiting the overall system performance available. In this application, by combining the characteristics of multi-carrier spatial modulation technology, different quality services will be provided to users in different channel conditions by improving user experience and improving overall system performance of broadcast channels. The basic idea of this application is to layer links using the correlation between links, so that data transmitted at different layers can obtain different protection. When the receiver detects data, it will select the detected data layer according to its channel conditions. So, users with poor channel conditions will still be able to obtain basic data, but users with good channel conditions will be able to detect more data layers and obtain higher data rates.

First Example:

This embodiment introduces a multi-carrier spatial modulation system that provides layered transmission in combination with specific system parameter settings. Assuming that the base station is equipped with 16 transmit antennas, that is, up to 16 links can be activated simultaneously. Available time-frequency resources use PRB (Physical Resource Block) specified in LTE as a unit, and one PRB consists of 12 subcarriers in 14 adjacent OFDM symbols. The number of system subcarriers is 256, and the number of available subcarriers is 120, i.e., 10 consecutive subcarriers in the frequency domain are considered. To verify the possibility of performing layered transmission using link correlation, Space Shift Keying (SSK) modulation is used in the present embodiment, i.e. one link is activated for each transmission, but each activated link does not transmit a QAM signal, but instead transmits a signal that is known to both the transmitting and receiving sides. The channel model is:

는 평탄 페이딩(flat fading) MIMO 행렬이며, 즉, 이의 요소는 평균값이 0이고, 분산(variance)이 1인 독립적인 복소 가우시안 분포를 따른다.

는 송신 측 공간 상관 행렬이며, 이는 송신 측에서 링크 사이의 상관 관계(링크 간 상관 관계)를 측정하기 위해 사용된다. 행렬 R_T의 요소는 다음과 같이 표현될 수 있다:Here, H∈C is the frequency domain equivalent channel coefficient matrix,

is a flat fading MIMO matrix, that is, its elements follow an independent complex Gaussian distribution with a mean of 0 and a variance of 1.

is the transmitting side spatial correlation matrix, which is used to measure the correlation between links (inter-link correlation) on the transmitting side. The elements of matrix R _T can be expressed as:

The element represents the correlation between the m-th link and the n-th link, d _m,n is the distance between the m-th link and the n-th link, d _min represents the minimum distance between links, and ρ represents the correlation coefficient. , ()* indicates conjugation.

Layered data transmission services are provided in the form of layering and grouping between links. A preferred link grouping criterion is the correlation between links, as shown in Figure 3. In Figure 3, all links are divided into N groups according to the correlation between the links, each labeled as group 1, group 2,... group N. Here we assume that the spatial modulation system activates only one link. After grouping, b ₁ to b _n are used to indicate activated links, and “inter-group” means any group to which the activated link represented by bits belongs; “Intra-group” means any specific location within the group to which an activated link belongs, represented by bits. In this form of grouping, links with stronger correlations (i.e., correlation indices greater than a set threshold) are placed into one group, and links belonging to different groups have relatively lower correlations. Meanwhile, the upper bits of the transmission bit group are used to indicate which group the activated link is in, while the lower bits are used to indicate the activated link within the group (that is, which link within the group is activated). The method of grouping can be nested, that is, intra-group can continue to perform grouping according to correlation, thereby achieving the purpose of multi-layered data transmission. This should be noted.

In this embodiment, SSK modulation with 16 available links can transmit 4 bits of information in each communication, and all links are grouped into 3 layers. First, for the first layer of groups, the first eight links are grouped as one group, the latter eight links are grouped as one group, and the most significant bit indicates which group the link is activated for; Next, each link group is divided into two groups according to correlation, each group contains 4 links with higher correlation as the second layer of the group, the second most significant bit is the indication ( indication); Finally, the last two least significant bits are the third layer of the group and are used to indicate which of the four links in the group is active. Figure 4 shows a schematic diagram of bit grouping in this embodiment. As shown in Figure 4, in the 4-bit information, b ₁ is a bit representing the first layer of the group, b ₂ is a bit representing the second layer of the group, and b ₃ and b ₄ are the third layer of the group It is a bit representing .

First, consider the case where the receiving side is equipped with 4 links and the channel correlation coefficient ρ = 0.1. Figure 5 shows the bit error rates that can be achieved by different groups in this case. Here, the legend 'first layer' indicates the bit error rate of the first layer of the group, i.e. the most significant bit; 'Second layer' refers to the bit error rate of the group of the second layer, i.e. the second most significant bit; 'Third layer' refers to the bit error rate of the third layer of the group, i.e. the least significant two bits; 'Average' indicates the average bit error rate. In this case, it can be seen that the first layer of the group has the best bit error performance, but the third layer of the group has the worst performance. Under the same bit error rate, the performance of the first layer of the group is about 2 dB better than the performance of the second layer of the group and about 4 dB better than the performance of the third layer of the group. Therefore, on the receiving side, for users with good channel conditions and higher signal-to-noise ratio, all three layers of data can be decoded, but for users with lower signal-to-noise ratio, only the data group with the best bit error performance Only the first layer of can be obtained.

Next, consider the case where two links are equipped on the receiving side and the channel correlation coefficient ρ = 0.3. Figure 6 shows the bit error rates that can be achieved by different groups in this case. Here, the legend 'first layer' indicates the bit error rate of the first layer of the group, i.e. the most significant bit; 'Second layer' refers to the bit error rate of the second layer of the group, i.e. the second most significant bit; 'Third layer' refers to the bit error rate of the third layer of the group, i.e. the least significant two bits; 'Average' indicates the average bit error rate. Similar to the results in Figure 5, in this case, different groups can still achieve significant performance differences, so users can choose the appropriate data rate according to their channel conditions.

Finally, consider the case where two links are equipped on the receiving side and the channel correlation coefficient ρ = 0.5. Figure 7 shows the bit error rates that can be achieved by different groups when the links have high correlation. Here, the legend 'first layer' indicates the bit error rate of the first layer of the group, i.e. the most significant bit; 'Second layer' refers to the bit error rate of the second layer of the group, i.e. the second most significant bit; 'Third layer' refers to the bit error rate of the third layer of the group, i.e. the least significant bit; 'Average' represents the total bit error rate. In this case, the performance gap between different tiers is much more obvious. For example, when the bit error rate is 10 ^-3 , the performance of the first layer of data is about 5 dB better than the performance of the second layer of data, and about 8 dB better than the performance of the third layer of data.

The simulation results from Figures 5 to 7 show that the method in which layered data is transmitted using correlation between links is more effective when the receiving side is equipped with multiple antennas or when a certain correlation exists between links. ; Differentiated services can be provided to users with different signal-to-noise ratios while ensuring that users can obtain basic services.

These results described above illustrate that the link grouping method provided by the embodiment can provide different bit error rate performance between different groups, thereby facilitating the system to transmit different data for different groups. One possible way is to transmit the most basic information about the bits of the first layer of the group, and the bits of each subsequent layer of the group carry extension information based on this layer of data. For example, the extended information may be additional service data to the basic service, and may also be data that improves time-frequency definition or voice clarity. Therefore, each time a layer of data is decoded, the data rate can be improved based on the data of the previous layer. Another possible way is to transmit the most basic information about the bits of the first layer of the group, and the bits of each subsequent layer of the group (such as a parity bit for channel encoding or a repetition of the information of the first layer of the group). Sending duplicate information. Therefore, each time a layer of data is decoded, reliability can be improved based on the data of the previous layer, thereby improving the robustness of the system. To improve both data speed and reliability, the two methods described above can be combined.

In order to make it easier for the receiving side to detect the data of each layer, the data of each layer can be divided into blocks, and CRC check codes that are independent of each other can be added. Although this may slightly reduce the data rate, it can make it easier for users to perform layered data detection. Figure 8 shows a schematic diagram of this data layering method. In the figure, the first layer of data is the base data, and the other layers of data are extensions or duplications based on the first layer of data. The example shown in the figure divides each layer of data into data block 1 and data block 2, and adds independent CRC check codes to data block 1 and data block 2, respectively.

In the channels of this embodiment, links are grouped according to the correlation between the links. Since in the channel model used, closer links have higher correlation, in this embodiment grouping can be performed directly according to the order of the links. Since the majority of systems use dual polarized antennas, the groups of different polarized antennas can be considered independent of each other, so the first tier of the group can be determined by using the polarization direction between the different antennas. Grouping according to distance between antennas with the same polarization direction is also reliable, considering that adjacent antennas tend to have higher correlation. Additionally, channel state information from user feedback can also be used to determine which links have higher correlation, and grouping of links can be performed according to this information.

The simulation presented in this embodiment does not consider the case of transmission of constellation point symbols, such as QAM symbols or PSK symbols, in a real system, but part of the information may also be carried in the constellation point symbols for transmission. Most detection algorithms with low complexity used in practice consider the need to first detect used links and then perform subsequent constellation point symbol detection after determining which links are active at the sending side. Therefore, if link detection errors occur or link detection has higher uncertainty, this will have a serious negative impact on the detection of the constellation point symbol. In this case, the constellation point symbol can be processed as data whose priority or importance has been lowered one level for transmission. Another way to transmit a constellation point symbol is to transmit a separate data flow using the constellation point symbol, and determine whether to maintain the data flow by CRC detection. Although link detection may not be accurate in some special situations, such as when there are links with stronger correlations, such as stronger direct mapping paths, it can still ensure the accuracy of the constellation point symbol. In these cases, throughput may instead be improved by sending a separate data flow using the constellation point symbol. At this point, the data flow sent with the constellation point symbol may contain some auxiliary data to the primary data. , for example, there should be duplication or redundancy of some layers of data, or some new auxiliary data information.

Second Example:

This embodiment will provide a multi-carrier spatial modulation technique that supports preprocessed layered transmission at the transmitting side. In some real systems, due to the absence of feedback or the fact that the feedback is not ideal, the link grouping settings of the base station may not guarantee to meet the requirements of all users. At this point, the difference between different groups can be increased on the base station side by preprocessing the different links, thereby increasing the likelihood of accurate detection.

Preprocessing in this embodiment includes, but is not limited to, power allocation and phase rotation. The two preprocessing methods will each be described below.

1. Power allocation.

On the premise of not changing the average transmission power, the average transmission power of each group in the first layer is adjusted so that different groups have different average transmission powers; On the premise of not changing the average transmission power of each group in the first layer, the average transmission power of each group in the second layer is adjusted so that different groups in the second layer have different average transmission powers; The above-described procedure is performed recursively according to the above-described steps, and eventually a power allocation result for each group within each layer is obtained. To ensure that the detection of the previous layer is not affected by the power adjustment of the next layer, the power adjustment amount of the previous layer needs to be specified to be strictly higher than the power adjustment amount of the next layer. An example of power allocation between links is shown in Figure 9.

Figure 9 shows a grouping setup where the number of links available to a base station is 4 and two layers are used for transmission. Each group in the first layer contains two links; Each group in the second layer contains one link. Assuming that the average transmission power is 1, the average power of the two groups in the first layer is adjusted on the premise of not changing the average transmission power. For example, as shown in Figure 9, the average power of group 1 of the first layer is adjusted to 1+p, and the average power of group 2 of the first layer is adjusted to 1-p. On the premise of not changing the average power of each group in the first layer, the power of each group in the second layer is adjusted. For example, the average power of each group in the second layer is adjusted to 1+p+p ₁ , 1+pp ₁ , 1-p+p ₁ , 1-pp ₁ . To ensure that the detection of groups in the first layer is not affected by the power allocation in the second layer, it is necessary to check that p > p ₁ .

2.Phase rotation.

Aside from power adjustment between different links, the difference between different groups can be increased through phase rotation. One possible criterion for phase rotation is to randomly select a rotation phase for the links of each group of the lowest layer, such that the randomly selected phase intervals for each group do not intersect, and adjacent phase intervals do not intersect those of the previous layer. Selected for links belonging to the same group. Since the number of groups in the lowest layer is 4, the number of links is 4 and the number of layers is 2, still using the system shown in Figure 9 as an example, a phase interval of 4 is selected as the phase rotation interval. Groups 1 and 2 of the second layer belong to the same group of the first layer (i.e., group 1 of the first layer), and groups 3 and 4 of the second layer belong to different groups of the first layer (i.e., group 1 of the first layer). Considering that it belongs to group 2), adjacent rotational phase intervals are selected for groups 1 and 2 of the second layer, and other adjacent rotational phase intervals are selected for groups 3 and 4 of the second layer. The rotational phase intervals for the four groups of the second layer are as follows.

[0,π/8],[π/8,π/4],[π/2,5π/8],[5π/8,3π/4]

Additionally, note that the two methods described above can be combined to further increase the distance between different groups, i.e., power adjustment and phase rotation can be performed simultaneously.

When transmitting a reference signal used for group channel estimation (the reference signal can be used for demodulation of each group), the reference signal passes the same preprocessing, and thus the reference signal is directly used for the estimation of the preprocessed equivalent channel coefficients. can be used Moreover, for a real system based on physical resource block scheduling, each time-frequency resource from the same physical resource block uses the same preprocessing method.

Third Example:

This embodiment will illustrate the operational flow of a multi-carrier spatial modulation technique using layered transmission supported by the present solution in a real system.

Figure 10 shows a schematic diagram of the operational flow of the multi-carrier spatial modulation technique supporting layered transmission used by this embodiment. On the base station side, the user equipment (UE) is first notified of the number of links used for data transmission and link grouping setting information; The data to be transmitted is then stratified according to information about the number of selected links and link grouping setting information; A reference signal corresponding to the selected link is transmitted, and data to be transmitted is transmitted to the UE after performing multi-carrier spatial modulation. Here, the link number information may be set in advance or included in the link grouping setting information, and therefore the link number information is optional information to be transmitted. In addition, a pattern for link grouping can be set, and the base station can specify a specific link grouping pattern to the UE so that the UE can obtain information about the links included in each group as well as the grouping of links.

On the UE side, link number information and link grouping setting information are first obtained. Then, the link channel state information is estimated by the reference signal of each link or group according to the information. Finally, detection of the data flow is performed to estimate the transmitted data.

Link number information indicates the number of links used to transmit spatially modulated signals. Since base stations often tend to be equipped with more antennas, they can support more links. However, in view of different channel conditions and served users, there is a need to select an appropriate number of links according to the specific situation. Link grouping setting information refers to the grouping of links after the number of links is selected. For a number of links of one type, only one or two link grouping settings need to be specified. For example, when the number of links used by the base station is 8, one possible link configuration is to place every 4 links in one group as the first layer, and then place every 2 links in one group as the second layer. Assigned to groups; Alternatively, every two links are assigned to one group as the first layer. Specific link grouping settings may also be determined by channel conditions and user settings. In conjunction with the link number information and link grouping setting information, the specific grouping setting used by the base station may be determined.

The following is a detailed description of the above-described process.

When the base station notifies the UE of link number information and link grouping configuration information, the information may be transmitted through a Physical Broadcast Channel (PBCH) or a Physical Downlink Control Channel (PDCCH). While transmitting on PBCH, the following two formats can be selected.

1. A new field is added to the PBCH to transmit link number information and link grouping setting information.

As shown in Figure 11, two fields, namely the link number information indication field and the link grouping setting information indication field, are each added to the reserved bits of the PBCH (as shown in the additional fields in Figure 11). .

Since the specified number of antenna ports is 1, 2 or 4 in the PBCH, the user performs detection in the form of blind detection and detection of CRC mask, and therefore only needs to be notified if the number of antenna ports is greater than 4. For example, if the base station is equipped with 128 antennas, the numbers of links that can be used by multi-carrier spatial modulation are 2, 4, 8, 16, 32, 64, and 128 (i.e., powers of 2). When notifying the number of links used, only cases where the number of links is greater than 4 are notified. One possible notification method is shown in Table 2.

[Table 2]

Table 2: One possible way to represent link count information when the link count is 128.

In Table 2, 3 bits are used to inform the UE how many links the last two cases are reserved, showing that more links can be supported in this way. Moreover, considering that the same number of links only needs to support one or two grouping settings to meet the layered transmission requirements, so the two newly added fields only need to occupy 4 bits. Considering that the number of reserved bits is 10 in PBCH, an overhead of 4 bits is therefore acceptable.

2. Link number information is transmitted using the CRC mask.

A method of informing the user of the number of antenna ports in a conventional PBCH channel is transmission mode blind detection plus CRC mask, that is, adding a mask corresponding to the number of each antenna port to the CRC check code. By adding an available CRC mask, link number information can be communicated to the user without additional fields.

Figure 12 shows a preferred method of conveying link number information using a CRC mask. Transmission modes used by PBCH include single antenna port mode, dual antenna port antenna diversity mode, and four antenna port antenna diversity mode. To ensure the reliability of PBCH transmission of information, the available CRC masks can be divided into three groups, respectively corresponding to single antenna ports, dual antenna ports and four antenna ports. In the example shown in Figure 12, CRC masks 1, 2, and 3 all correspond to a single antenna port. Therefore, by decoding one of the masks, the user can determine that the transmission mode used by the PBCH is single antenna port mode. Each CRC mask in turn represents information on the number of links used by the actual broadcast channel. For example, if the number of links used by the broadcast channel is set to 16 and the PBCH transmission uses single antenna port mode, CRC mask 3 is selected to process the CRC check bit. After the user knows by CRC check that mask 3 is used, the user can see that the PBCH transmission mode is single antenna port mode and the number of links used by the broadcast channel is 16. When using this method, the user is notified of link grouping configuration information by adding extra fields to the reserved bits.

Moreover, these two methods described above can be combined, that is, using the CRC mask to notify the number of ports while adding an extra field to the reserved bits in the PBCH, thus improving the reliability of information.

The above-described link number information and link grouping setting information can also be transmitted in the downlink control channel, that is, adding an extra field to the control channel to indicate the link number information and link grouping setting information. One possible way to represent link number information is shown in Table 2, where bit 000 indicates that the link configuration used is the same as that of the PBCH.

In addition to these two methods, link number information and link grouping setting information may also be transmitted in the Physical Downlink Shared Channel (PDSCH).

Data is stratified by base station based on one or more of the following criteria:

1. Tiering according to the priority of data, that is, data with the highest priority is assigned to the bit layer with the highest stability; The data with the second highest priority is assigned to the second highest confidence bit layer; By this analogy, data with the lowest priority is assigned to the bit layer with the lowest reliability. Here, the priority may be that of the application data, i.e. data with the highest priority requires more efficient and more reliable decoding, while data with lower priority meets the requirements for reliability. It can be alleviated. The priority can also be the priority of the multimedia data, that is, the data with high priority is the basic data, and by decoding the data with high priority, the basic multimedia service can be obtained, and that of the low priority data. With additional detections, the quality of service can be improved based on the basic service.

2. Alternatively, the bit layer with the highest reliability transmits basic information bits. After performing channel encoding on the basic information bits, redundant information bits are transmitted in the second highest reliability bit layer, and redundant bits resulting from further encoding are transmitted in the lower reliability bit layer. Accordingly, once the hierarchy of data is detected, the reliability of the received signal can be improved. Moreover, the two types of layering methods described above can be combined to simultaneously increase data rate and reliability.

For data detection, users can use the following two methods:

1.Joint detection. That is, the user performs joint detection for each data layer and obtains an estimated value of the transmitted data of each layer. Then, the received signal-to-noise ratio is estimated for each data layer, and layered data flows exceeding a certain threshold are selected for further processing (such as channel decoding and source decoding, etc.); If layered data is processed by adding a CRC per block, a CRC check can be performed for each data layer, and each layer that passes the check is maintained.

2. Detection by layer. That is, until the received signal-to-noise ratio of a certain layer cannot reach a certain threshold or the CRC check of a certain layer fails, the information transmitted on each data layer is transmitted according to the channel state information of each layer. Detected by layer.

Fourth Embodiment:

In this embodiment, a reference signal setting method using the solution provided by this application will be presented.

The reference signals can be processed according to the insertion method used in conventional communication systems, that is, the reference signals used for estimation of different link channels use resources orthogonal to each other for transmission, i.e. the transmission uses frequencies orthogonal to each other. Mutually orthogonal codes are used to distinguish between domains, time resources, or links that occur in the same time-frequency resource but are different. This method can estimate channel state information for each link. Data detection can be performed in a joint manner from each group, and data from groups whose confidence reaches beyond some threshold are selected for further processing. The channel state information of each group can also be obtained through combination, and then each data layer can be detected through layer-by-layer detection, until the signal of any layer reaches the threshold of signal-to-noise ratio. .

In this embodiment, a group scheme for transmitting reference signals will be presented. The basic idea is to simplify the design of the receiver by transmitting a group's reference signal so that each data layer can be directly detected from the group's channel state information. Figure 13 shows a simple example of a group transmitting a reference signal where the number of links on the transmitting side is 8 and the number of layers is 3. In Figure 13, the first layer of groups includes two groups, and each group includes four links. To distinguish between the two groups of the first layer, two orthogonal reference signals of length 2 are needed, as shown as RS1 and RS2 in the figure. When transmitting the reference signal of this layer, under the premise of power constraints, four links belonging to the same group transmit the same reference signal data, and four links belonging to another group transmit the reference signal orthogonal to the signal. Transmit signal data. Each group in the second layer of groups contains two links; Additionally, only two mutually orthogonal reference signals of length 2 are needed to distinguish two different groups. In particular, in Figure 13, Link 1 and Link 2 transmit the same reference signal, RS3, while Link 5 and Link 6 transmit a reference signal orthogonal to that signal, RS4, and the remaining links are not activated. The channel state information of the other two groups may be calculated by combining the channel state information of the first layer group. When transmitting the channel state information of the third layer of the group, four orthogonal reference signals with a length of 4 are used as RS5 to RS8, that is, only the channel state information of links 1, 3, 5, and 7 need to be estimated. However, the channel state information of the remaining links can be obtained in combination with the channel state information of the second layer.

The group's method of transmitting the above-described reference signal can simplify user operations without consuming additional resources, so users with poor channel conditions can decode basic data faster.

Figure 14 shows a schematic diagram of time-frequency resource allocation for groups transmitting reference signals. For the example shown in Figure 13, the conventional scheme of reference signal transmission requires eight orthogonal reference signals and therefore eight orthogonal time-frequency resources. From the above description, layer 1 requires two orthogonal reference signals and therefore two orthogonal time-frequency resources; Layer 2 requires two orthogonal reference signals and therefore two orthogonal time-frequency resources; Layer 3 requires four orthogonal reference signals and therefore four orthogonal time-frequency resources. Therefore, the time-frequency resources required by the present invention are the same as those of the conventional method, but the present invention can support better layer-by-layer detection and is more advantageous for users with poor channel conditions.

Fifth Embodiment:

In this embodiment, a solution is presented to determine link grouping settings and user group settings according to channel state information from users' feedback.

Although the multimedia broadcast/multicast service in LTE-A does not support adjusting the process at the transmitting side according to the user's feedback information, for the solution proposed by this application, the use according to the channel state information from the user's feedback Adjusting the number of links and link grouping settings can better serve users in different channel conditions. On the other hand, solutions based on feedback may also be suitable for users whose services are in open loop mode. In particular, as shown in Figure 15, according to the channel state information from the user's feedback, the base station allocates users with the same or similar link number information and link grouping setting information into one group, and the same time-frequency A broadcast service is performed on the resource.

The specific grouping process is depicted as in Figure 16. On the base station side, a downlink reference signal is transmitted to measure channel state information of the downlink physical channel. This reference signal may be similar to a cell-specific reference signal (CRS) or a channel state information reference signal (CSI-RS) in LTE/LTE-A. The reference signal plays a different role from the reference signal described in the second embodiment. The UE estimates the downlink channel based on the reference signal and feeds back the estimated channel state information to the base station. The base station estimates the correlation between links according to feedback from the UE, determines the user's link grouping settings, assigns users with the same or similar link grouping settings to one group, and A broadcast service is performed for the same time-frequency resource.

To measure the correlation between links, the base station can also estimate the correlation between downlinks by estimating the uplink channel state information according to the Sounding Reference Signal (SRS) transmitted from the UE to the base station through the uplink channel. You can. For a Time-Division Duplex (TDD) system, using the reciprocity between uplink and downlink channels, the correlation between downlinks can be obtained directly. For Frequency Division Duplex (FDD) systems, since the correlation between links is influenced and determined by the large-scale fading between channels, the correlation between downlinks is therefore also estimated by the uplink channel estimation. It can be.

Users can feed back channel state information through RI (Rank Indication) and PMI (Precoding Matrix Index) that exist in LTE. The base station estimates the correlation between downlinks based on user feedback. For the convenience of user feedback, a link grouping setting pattern codebook known to both the base station and the user can also be designed, and the user feeds back the link number information through RI and the necessary link grouping setting through the link grouping setting pattern. .

Through estimation of the correlation between user links, the base station can dynamically adjust user groups and inform users of the time-frequency resource locations where broadcast data is needed on the downlink control channel or downlink shared channel. The user reads the information of the downlink control channel or the downlink shared channel, and obtains broadcast data resource allocation information as well as information about the number of links used and link grouping setting information. Based on this information, the user obtains broadcast data from each source.

The signal processing flow of the multi-carrier spatial modulation system, including user grouping, preprocessing, and based on group transmission, is shown in Figure 17. Selecting user grouping and link settings based on feedback/uplink transmission is optional. The structure shown in FIG. 17 is not only suitable for control channel transmission but also for providing a multimedia broadcast/multicast service broadcast channel. When applying this structure to a control channel, the basic data includes some control information needed by the system, and the extension data may be some extended control data to increase the transmission data rate of the control channel or increase the reliability of the control channel. It may be a duplication or copy of the underlying data to be used; It can also be used in receivers operating in open loop mode, where receivers in this kind of mode cannot feed back channel state information efficiently. With the solution provided by the present application, the receiver can voluntarily adjust the rate at which it receives data according to changes in channel conditions, providing greater flexibility and reliability.

Corresponding to the above-described method, the present application provides a transmitter, the structural structure of which is shown in Figure 18. The transmitter is,

A setting module for transmitting link grouping setting information, wherein the link grouping setting information is information about links included in each group after dividing links into at least two groups. the settings module;

a data layering module for layering transmitted data flows according to groups of links;

a spatial modulation module for performing spatial modulation on the layered data flow;

a multi-carrier modulation module for performing multi-carrier modulation on a spatially modulated signal; and

It includes a transmission module for transmitting a multi-carrier modulated signal.

Corresponding to the above-described method, the present application also provides a receiver, the structural structure of which is shown as in Figure 19. The receiver is,

a configuration information receiving module for receiving link grouping configuration information;

a group acknowledgment module for obtaining grouping and link information of links included in each group according to the link grouping setting information; and

It includes a detection module to perform layered detection on the received data according to the grouping of links.

Example 6:

In this embodiment, a downlink physical channel training solution applicable to multi-carrier spatial modulation is described with reference to example system parameter settings. In this embodiment, the base station is equipped with N antennas, and the terminal is equipped with M antennas. These systems operate in time division duplex (TDD) mode. Accordingly, the state of the uplink channel can be used for the downlink channel according to channel correlation.

Figure 20 is a schematic diagram showing a preprocessing-based multi-carrier spatial modulation system according to the first embodiment of the present disclosure. From Figure 20, it can be seen that compared with the conventional multi-carrier spatial modulation system, the preprocessing-based spatial modulation system provided by this embodiment adds a preprocessing module between the spatial modulation and IFFT modules. The basic idea is to perform spatial modulation operations on equivalent channels consisting of preprocessing → IFFT → channel → FFT to increase link reliability, reduce pilot overhead, and support multiple simultaneous serving terminals. In this embodiment, the signal processing procedure in TDD mode is as shown in Figure 21 and is briefly described below.

First, the terminal transmits an uplink SRS (Sounding Reference Signal) to the base station. The base station estimates the system frequency domain channel according to the received SRS and obtains a channel coefficient matrix H∈C ^MxN composed of frequency domain channel coefficients.

Then, the base station calculates the preprocessing basic matrix W _b ∈ C ^NxM according to the channel coefficient matrix. Preprocessing includes MF (Matched-Filter) precoding, i.e. W _b =H ^H , ZF (Zero-Forcing) precoding, i.e. W _b =H ^H (HH ^H ) ^-1 or MMSE (Minimum Mean Square Error) precoding, etc. It may be implemented in a manner that includes, but is not limited to.

Then, the base station expands the preprocessing basic matrix to obtain the expanded preprocessing matrix W∈C ^NxN . The preprocessing base matrix can be expanded through any of the following three methods:

가 행렬 W_b의 제 m 열 벡터를 나타내는

이며이면, 행렬 W의 제 n 열 벡터 w_n은

로에 의해 나타내어질 수 있으며, 여기서,

는 w_n을 생성할 때 벡터 W_b에 대한 선형 결합 계수를 나타낸다. 선형 결합 계수는 수신 단에 의해 수신된 심볼 사이의 유클리드 거리(Euclidean distance)를 가능한 한 크게 하기 위해 선택된다(또는 등가 채널 벡터 사이의 유클리드 거리를 가능한 한 크게 한다). 하나의 간단한 조건은 선형 결합 계수가 실수이고, 반대 수가 없다는 것이다. 이러한 조건은 가능한 조건 중 하나일 뿐이다. 심볼 사이의 유클리드 거리를 가능한 한 크게 보장할 수 있는 임의의 조건이 적용 가능하다.First expansion method: Linear combination, that is, linear combination of the columns of the preprocessing basic matrix is performed to obtain the columns of the expanded preprocessing matrix. for example,

represents the mth column vector of matrix W _b

, then the nth column vector w _n of matrix W is

It can be expressed by , where:

represents the linear combination coefficient for vector W _b when generating w _n . The linear combination coefficient is selected to make the Euclidean distance between symbols received by the receiving end as large as possible (or to make the Euclidean distance between equivalent channel vectors as large as possible). One simple condition is that the linear combination coefficients are real numbers and have no inverses. This condition is only one of possible conditions. Any condition that can ensure that the Euclidean distance between symbols is as large as possible is applicable.

에 의해 나타내어질 수 있으며, 여기서 벡터

는 전처리 기본 행렬의 제 m 열을 나타내고, j는 허수 단위이고,

는 회전각을 나타낸다. 게다가, 위상 회전은 각각의 열 벡터의 요소에 상이한 회전 인수를 곱하거나, 열 벡터에 N×N 회전 행렬을 곱하는 것과 같은 다양한 방식을 통해 구현될 수 있다.Second expansion method: Phase rotation, that is, perform phase rotation on the column vector of the preprocessing basic matrix to obtain the column vector of the expanded preprocessing matrix. In particular, the nth column of the extended preprocessing matrix is

It can be represented by , where the vector

represents the mth column of the preprocessing basis matrix, j is the imaginary unit,

represents the rotation angle. Additionally, phase rotation can be implemented through a variety of ways, such as multiplying the elements of each column vector by a different rotation factor, or multiplying the column vector by an N×N rotation matrix.

에 의해 나타내어질 수 있으며, 여기서,

는 전력 할당 인수를 나타낸다.Third expansion method: power allocation, that is, each column vector of the preprocessing basic matrix is multiplied by the power allocation factor to obtain the columns of the expanded preprocessing matrix. In particular, the nth column of the extended preprocessing matrix is

It can be expressed by, where:

represents the power allocation factor.

It should be noted that the three methods described above can be used in combination. For example, a linear combination of the columns of the preprocessing basis matrix may be performed first to obtain an NxN matrix, and then phase rotation and power allocation operations may be performed on this matrix to obtain the final expanded preprocessing matrix.

이며, 행렬 W는 특정 규칙에 따라 생성된다. 따라서, 단말기가 규칙을 알고 있으면, 단말기는 채널 추정이 적은 선형 결합의 규칙에 따라 완전한 채널 행렬을 생성할 수 있다. 특히 기본 등가 채널은 다음에 의해 정의된다:Finally, when transmitting data to the terminal, the base station needs to perform downlink equivalent channel training. The equivalent channel experienced by the data transmitted by the base station is

, and matrix W is generated according to specific rules. Therefore, if the terminal knows the rule, the terminal can generate a complete channel matrix according to the rule of linear combination with less channel estimation. In particular, the basic equivalent channel is defined by:

은 다음에 의해 나타내어진다:On the other hand, the equivalent channel

is represented by:

로 수행되면, 등가 채널

의 추정이 획득될 수 있다는 것을 알 수 있다. 이것은 다운링크 등가 채널을 추정할 때, 기본 등가 채널

을 추정하기 위해서만 필요로 되고, 등가 채널

의 추정은 필요로 되지 않는다는 것을 의미한다. 따라서, 다운링크 채널 추정에 대한 오버헤드가 효과적으로 감소된다.The expansion operation corresponding to generating the preprocessing matrix is the default equivalent channel

When performed as, the equivalent channel

It can be seen that an estimate of can be obtained. When estimating the downlink equivalent channel, this is the basic equivalent channel

is only needed to estimate the equivalent channel

This means that estimation of is not necessary. Accordingly, the overhead for downlink channel estimation is effectively reduced.

In particular, when performing downlink training, the base station estimates M downlink basic equivalent channels, performs preprocessing on the downlink reference signal with the preprocessing basic matrix W _b , and transmits the preprocessed downlink reference signal to the terminal. You just need it to do it. After completing the downlink basic equivalent channel training, the base station uses matrix W to perform preprocessing on the downlink data.

During downlink equivalent channel training, the signal received by the terminal can be represented by:

Y _P = HW _b P+N;

는 기준 신호 행렬을 나타내며, M_P는 기준 신호의 길이를 나타낸다. 예를 들어, M_P=M, 행렬 P는 단위 행렬이고, 즉 기준 신호는 직교 시간-주파수 자원 상에서 송신된다. 단말기는 기준 신호 행렬 P를 알고 있기 때문에, 단말기는 기본 등가 채널

의 추정치

를 획득할 수 있다. 한편, 단말기는 전처리 기본 행렬로부터 확장된 전처리 행렬을 생성하기 위한 확장 규칙을 이미 알고 있으므로, 단말기는 전처리 기본 행렬을 확장할 때 송신단과 동일한 방식을 사용하여 확장된 등가 채널 행렬

의 추정치

를 복원할 수 있다. 데이터가 송신될 때, 단말기에 의해 수신된 신호는 다음에 의해 나타내어질 수 있다:here,

represents the reference signal matrix, and M _P represents the length of the reference signal. For example, M _P =M, the matrix P is an identity matrix, that is, the reference signal is transmitted on orthogonal time-frequency resources. Since the terminal knows the reference signal matrix P, the terminal uses the basic equivalent channel

estimate of

can be obtained. Meanwhile, since the terminal already knows the expansion rules for generating an expanded preprocessing matrix from the preprocessing basic matrix, the terminal uses the same method as the transmitting terminal when expanding the preprocessing basic matrix to obtain the expanded equivalent channel matrix.

estimate of

can be restored. When data is transmitted, the signal received by the terminal can be represented by:

에 따라 송신 신호를 추정하여, 추정된 비트 스트림을 출력한다.Here, x∈C ^Nx1 represents the transmitted signal after spatial modulation, and y∈C ^Mx1 represents the signal received by the terminal. The terminal estimates the received signal y and the extended equivalent channel matrix.

The transmission signal is estimated according to and the estimated bit stream is output.

In this solution, it can be seen that the expanded preprocessing matrix is obtained by multiplying the preprocessing base matrix and the expansion matrix, that is, the finally obtained expanded preprocessing matrix is calculated as:

W = W _b W _e

. 확장된 등가 채널과 기본 등가 채널은

을 충족한다. 따라서, 수신단이 확장 행렬 W_e을 알고 있다면, 이는 기본 등가 채널의 추정에 기초하여 확장된 등가 채널을 복원할 수 있다. 이 때, 다운링크 기준 신호의 오버헤드는 기본 등가 채널의 차원과만 관련이 있다. 시스템 스펙트럼 효율에 대한 다운링크 트레이닝의 영향은 크게 감소된다.Here, W _e ∈ C ^MxN represents an expansion matrix, and can be designed according to the three expansion methods described above in this embodiment. During channel estimation, the basic equivalent channel is expanded first;

. The extended equivalent channel and the basic equivalent channel are

meets. Therefore, if the receiving end knows the extension matrix W _e , it can restore the extended equivalent channel based on the estimation of the basic equivalent channel. At this time, the overhead of the downlink reference signal is only related to the dimensions of the basic equivalent channel. The impact of downlink training on system spectral efficiency is greatly reduced.

Below, an example is provided to explain parameter settings. Assume the system is a multi-antenna system with QPSK modulation, N=16, M=2. If conventional multi-carrier spatial modulation is used, 6 bits can be transmitted each time. At the same time, downlink training is required to estimate a total of 16 links, which places a large burden on the system spectral efficiency. However, according to the solution of this disclosure, it is only necessary to estimate two basic equivalent channels, which can greatly reduce the overhead of channel training. In this example, linear combination and phase rotation expansion methods are used to expand the preprocessing basis matrix. The preprocessing basis matrix generated by the transmitting side has dimensions of 16x2. A linear combination of the columns of the matrix is performed to obtain the expanded intermediate matrix. The linear combination coefficients are shown in Table 3.

[Table 3]

[Table 3] Linear combination coefficient

To obtain the final preprocessing matrix, a phase rotation is performed on the columns of the intermediate matrix. All elements of the same column vector use the same phase rotation factor. In this embodiment, two adjacent rows use the same phase rotation factor, for example multiples of 11.25°.

Before the data is transmitted, a reference signal matrix is transmitted after being processed by a preprocessing fundamental matrix, and then the data is transmitted after spatial modulation and processing based on the extended preprocessing matrix. The receiving end estimates the downlink basic equivalent channel according to the reference signal, expands the columns of the basic equivalent channel matrix according to Table 3 and the phase rotation processing rules, and obtains the expanded equivalent channel. Finally, the terminal obtains an extended equivalent channel matrix and an estimated bit stream according to the received signal.

It should be noted that the solution of the present disclosure forms an equivalent link between the transmitting end and the receiving end, so multiple links can be activated simultaneously based on the equivalent link to realize generalized spatial modulation.

Embodiment 7:

In this example, the effectiveness of the solutions of the present disclosure is demonstrated with reference to parameter settings in real systems and simulated results. Assuming that the system uses 256 subcarriers, the number of effective subcarriers used to transmit data is 120. Twelve consecutive subcarriers of 14 OFDM symbols form a physical resource block (PRB). It is assumed that the transmitting end knows the channel state information. According to the channel state information, the base station calculates the preprocessing fundamental matrix according to the matched filter precoding algorithm, that is,

W _b = H ^H .

Afterwards, the base station expands the preprocessing basic matrix according to the expansion method described in Embodiment 1 and performs preprocessing on the data. The EVA channel model is utilized. The moving speed of the terminal is 50 km/h.

First, a situation where the base station has 16 antennas and the terminal has 2 antennas is considered. QPSK modulation method is adopted. In this situation, the spectral efficiency is 6bps/Hz. The expansion of the preprocessing fundamental matrix is similar to Example 1, that is, linear combination and phase rotation are performed on the columns of the preprocessing fundamental matrix. The linear combination coefficients are shown in Table 3. A conventional multi-carrier spatial modulation system is selected for comparison. The system structure of a conventional multi-carrier spatial modulation system is shown in Figure 1.

Figure 22 is a schematic diagram showing a comparison of bit error rate performance of the preprocessing solution of the present disclosure and the conventional solution. The horizontal axis represents E _s /N ₀ , where E _S represents the average energy of the transmitted symbols at each time, normalized to 1 in this embodiment. N ₀ represents the noise spectral density used to evaluate the noise energy. It can be seen that with the preprocessing provided by the present disclosure at the same data rate, the bit error rate performance of the multi-carrier spatial modulation system is greatly improved. For example, around a bit error rate of 10 ^-3 using the preprocessing method provided by this disclosure, system performance is improved by about 7 dB compared to a conventional multi-carrier spatial modulation system.

From the above, it can be seen that the embodiment of the present disclosure first generates an energy concentrated link through preprocessing to optimize the signal-to-noise ratio at the receiving end. Based on these links, new virtual links are created based on methods such as power allocation, phase rotation and linear combining to provide higher spectral efficiency using the link index. Therefore, the performance comparison results provided by this embodiment can be explained in the following two aspects: 1. Since the channel state information known by the transmitting end is used, basic preprocessing focuses transmission energy, thereby improving the basic link The signal-to-noise ratio of the receiving end of the phase can be greatly increased; 2, Through preprocessing at the transmitting end, the generated new virtual link ensures that the Euclidean distance between symbols is relatively large, which further improves the bit error rate performance of the system.

는 허수 단위이며, θ=π/8은 회전각을 나타낸다.Then, a situation is considered where the base station has four transmit antennas and the terminal has one receive antenna. The QPSK modulation method is still used. At this time, the spectral efficiency is 4bps/Hz. Since the receiving end has only one antenna, the equivalent channel after conventional precoding is a single input single output channel. Linear combination preprocessing cannot be performed. Therefore, only phase rotation expansion on the preprocessing basis matrix is performed. In particular, the i (1≤i≤4) column of the extended preprocessing matrix W is w _b exp{jx(i-1)θ}, and the vector w _b ∈C ^4x1 is the preprocessing basic vector calculated according to the channel state information. represents. The calculation may be performed based on a matched filter precoding algorithm.

is an imaginary unit, and θ=π/8 represents the rotation angle.

Figure 23 compares the bit error rate performance of the conventional solution and the preprocessing solution of the present disclosure. It can be seen that the bit error rate performance of both solutions deteriorates due to the reduction of the receiving antenna of the terminal. However, the solution of the present disclosure still has excellent performance. For example, around a bit error rate of 10 ^-2 , a preprocessed multi-carrier spatial modulation system has a performance advantage of more than 5 dB.

Example 8:

In this embodiment, the support of the solution provided by this disclosure for a multi-user MIMO system is described. In this embodiment, the multi-user MIMO system based on preprocessing spatial modulation is as shown in FIG. 24.

이다. 송신 데이터에 대한 전처리를 수행할 때, 기지국은 먼저 기지국으로부터 모든 단말기로의 채널 상태 정보에 따라 주파수 도메인의 프리코딩 행렬을 계산하여 각각의 단말기에 대한 프리코딩 행렬을 획득한다. 그런 다음, 기지국은 확장된 전처리 행렬을 획득하기 위해 실시예 1의 솔루션에 따라 각각의 단말기의 프리코딩 행렬을 확장하고, 각각의 단말기의 데이터에 대한 전처리를 수행한다. 전처리 후에, 기지국은 조합 모듈에서 전처리된 데이터를 조합하며, 즉 동일한 안테나 상에 송신될 데이터를 부가한다. 그런 다음, 기지국은 조합된 데이터를 안테나를 통해 송신하기 전에 조합된 데이터에 대한 IFFT 연산을 수행한다.In Figure 24, the number of terminals serviced simultaneously is K. The base station is equipped with N antennas. The ith terminal is equipped with M _i antennas. The total number of receiving antennas is

am. When performing preprocessing on transmission data, the base station first calculates a precoding matrix in the frequency domain according to channel state information from the base station to all terminals to obtain a precoding matrix for each terminal. Then, the base station expands the precoding matrix of each terminal according to the solution of Embodiment 1 to obtain an expanded preprocessing matrix, and performs preprocessing on the data of each terminal. After preprocessing, the base station combines the preprocessed data in a combination module, i.e. adds data to be transmitted on the same antenna. The base station then performs an IFFT operation on the combined data before transmitting the combined data through the antenna.

In particular, each of the M antennas of the K terminals is viewed as a receiving end. The frequency domain channel model between the base station and the receiving end can be expressed as follows:

y = Hx+n,

는 제 i 단말기의 프리코딩 기본 행렬을 나타낸다. 행렬 W_i는 실시예 1의 솔루션에 따라 확장되어 제 i 단말기의 확장된 프리코딩 행렬 W_E,i∈C^NxN을 획득한다. 그 후, 각각의 단말기에 대해, 하나의 링크가 N개의 가상 링크로부터 선택되어 변조 차수 Q를 가진 심볼을 송신하고, 대응하는 확장된 프리코딩 행렬을 사용하여 송신 벡터에 대한 프리코딩이 수행되며, 심볼은 IFFT 후에 안테나를 통해 송신된다. log₂(NQ) 비트는 각각의 단말기로 송신될 수 있음을 알 수 있다.Here, H∈C ^MxN represents the frequency domain equivalent channel matrix. Precoding processing is performed on these matrices to eliminate interference between terminals before transmitting data. Common precoding solutions include matched filter precoding, zero forcing precoding, MME precoding, and block diagonal precoding. Taking zero forcing precoding as an example, the precoding basis matrix W _P is calculated by W _P =H ^H (HH ^H ) ^-1 = [W ₁ W ₂ ...W _K ], where:

represents the basic precoding matrix of the i-th terminal. The matrix W _i is extended according to the solution in Example 1 to obtain the extended precoding matrix W _E,i ∈C ^NxN of the ith terminal. Then, for each terminal, one link is selected from the N virtual links to transmit symbols with modulation order Q, and precoding is performed on the transmission vector using the corresponding extended precoding matrix, The symbols are transmitted through the antenna after IFFT. It can be seen that log ₂ (NQ) bits can be transmitted to each terminal.

Through precoding, interference between terminals can be effectively reduced or even eliminated. Accordingly, a multi-user system may then be equally viewed as multiple single-user systems. In this way, the processing at each terminal is similar to the processing at the receiving end in a single user system. That is, first, FFT processing is performed on each link to obtain a frequency domain received signal, and then the received signal is demodulated according to channel estimation to obtain estimated transmission data. Downlink channel estimation requires estimating a basic equivalent channel composed of a preprocessing basic matrix and a frequency domain equivalent channel of each terminal. After obtaining the estimate of the equivalent channel through channel estimation, the terminal obtains the estimate of the extended equivalent channel through the same extension operation as the transmitting terminal, and uses the estimate of the extended equivalent channel for demodulation of the received signal.

Compared with the conventional multi-user large-scale MIMO system, if the terminal is equipped with a single antenna, the solution provided by this disclosure can have more information through the link index, so that under the same modulation scheme, the solution provided by this disclosure can transmit more bits. These additional bits can be used to increase system reliability through channel coding, or can be used to transmit data to increase system throughput or data rate. Alternatively, some of these bits can be coded, while other bits are used to transmit data, so that high throughput as well as high reliability can be obtained. For a terminal equipped with multiple receive antennas, multiple antennas can provide diversity gain and increase link reliability. Terminals with multiple antennas may also be viewed as multiple single-antenna terminals to provide higher throughput and data rates.

It should be noted that the above-described multi-user architecture is applicable to TDD mode or frequency division duplex (FDD) mode. In particular, in the case of TDD mode, the base station obtains downlink channel state information based on uplink channel estimation through channel correlation. In the case of FDD mode, the base station selects a preprocessing basic matrix for each terminal device according to the channel state information fed back by the terminal and performs an expansion operation.

Transmission of reference signals in a multi-user system is similar to Embodiment 1. Reference signals of different terminals use orthogonal resources (including time, frequency or orthogonal code book resources, etc.). The reference signal is processed according to the basic precoding matrix of each terminal and transmitted to the corresponding terminal. The terminal estimates its basic equivalent channel and extends the basic equivalent channel according to an extension method consistent with the base station to obtain an estimate of the extended equivalent channel. The basic equivalent channel of each terminal is defined as an equivalent channel coefficient matrix including the precoding fundamental matrix, multi-carrier modulation, the actual physical channel from the transmitting end to the terminal, and the multi-carrier demodulation of the terminal. The estimate of the extended equivalent channel of each terminal is defined as an equivalent channel coefficient matrix including the extended precoding matrix, multi-carrier modulation, the actual physical channel from the transmitting end to the terminal and the multi-carrier demodulation of the terminal.

Example 9:

Examples 6, 7, and 8 provide application and performance comparisons of the solutions provided by this disclosure under TDD mode. A common feature of these embodiments is that the base station knows accurate channel state information, which greatly facilitates the calculation of the precoding fundamental matrix at the transmitting end. However, in FDD mode, this is difficult to implement. This embodiment provides implementation under FDD mode.

In FDD mode, it is difficult for the base station to obtain accurate channel state information, which causes many difficulties in calculating the preprocessing fundamental matrix. However, based on the principles of the solution provided by this disclosure, the preprocessing fundamental matrix may be independent of the channel state information. Calculation of the preprocessing fundamental matrix based on known channel state information can increase the terminal's received signal-to-noise ratio, but the randomly selected preprocessing fundamental matrix can also be used to generate the fundamental channel link, and the virtual link can also be used as Example 1 It can be created through a similar method. Therefore, the solution of the present disclosure is also applicable to FDD mode. Hereinafter, implementation of the present disclosure in FDD mode is described with reference to embodiments.

Figure 25 is a flowchart illustrating a signal processing procedure based on a fixed preprocessing fundamental matrix in FDD mode according to an embodiment of the present disclosure. In this embodiment, since there is no need to calculate the preprocessing fundamental matrix according to the channel state information, the calculation does not depend on feedback from the terminal to the base station. In this embodiment, the signal processing procedure based on the fixed preprocessing fundamental matrix includes the following: First, the base station selects an appropriate code word from the fixed code book set as the preprocessing fundamental matrix. The matrix may be selected randomly or may be an appropriate code word selected according to channel state information fed back by the terminal. In the second situation, during downlink channel estimation, the base station may perform preprocessing on the transmitted reference signal based on a predefined code book. The terminal selects the code word with the maximum received signal-to-noise ratio and feeds back the index of the code word. The base station takes the code word fed back by the terminal as a preprocessing basic matrix. Then, after the preprocessing basic matrix is selected, the corresponding preprocessing matrix expansion operation can be performed. Similar to Example 1, linear combination, phase rotation, and/or power allocation may be performed on the columns of the preprocessing basis matrix to obtain the expanded preprocessing matrix. Finally, preprocessing is performed on the spatial modulation symbols transmitted with the extended preprocessing matrix, and the preprocessed symbols are transmitted through each antenna after IFFT operation.

Regarding channel estimation, the base station selects a preprocessing fundamental matrix, then transmits a demodulation reference signal used to estimate the basic equivalent channel, and performs preprocessing on the reference signal with the preprocessing fundamental matrix. After obtaining an estimate of the basic equivalent channel based on the demodulation reference signal, the terminal reports to the base station the estimate of the basic equivalent channel (including linear combination of columns, phase rotation and power allocation) to obtain an estimate of the extended equivalent channel. Performs an expansion operation matching . Finally, the terminal performs spatial demodulation processing on the received signal according to the estimate of the extended equivalent channel to obtain an estimate of the transmitted bit stream.

Hereinafter, the efficiency of the solution provided by this embodiment is explained with reference to performance simulation.

First, assume that the base station has four transmitting antennas and the terminal has one receiving antenna. QPSK modulation method is used. At this time, the spectral efficiency is 4bps/Hz. Among these, three solutions are considered:

The first solution adopts a fixed preprocessing basis matrix as described in this embodiment, and the preprocessing basis vector is fixedly selected at the base station as w _b = [1j1-j] ^T , where j is the imaginary unit.

The second solution adopts a fixed preprocessing fundamental matrix as described in this embodiment, and the base station selects a code word from a preset code book as the preprocessing fundamental matrix according to the channel state information fed back by the terminal. The code book used for simulation in this embodiment is described by the following matrix:

Here, each column of the matrix represents a code word, and the code words are orthogonal. j represents the imaginary unit. Preprocessing of the two solutions described above includes phase rotation and power allocation. The phase rotation angle is a multiple of π/8, and the power allocation ratio is P1:P2:P3:P4=5:6:7:8, where P _i is the transmit power of the i link, and the average transmit power is set to 1. It becomes normalized.

A third solution is a conventional multi-carrier spatial modulation system.

Figure 26 shows a comparison of the bit error rate performance of the three solutions described above. It can be seen that when the base station does not consider channel state information, i.e. the first solution where the same preprocessing basis matrix is selected for different subcarriers, the performance is inferior or similar compared to conventional multi-carrier spatial modulation. The advantages of this solution are: Only the equivalent channel needs to be estimated before expansion, thus reducing the overhead for downlink equivalent channel estimation. The second solution, which takes channel state information into account, has clear advantages. For example, when the bit error rate is about 10 ^-2 , the third solution has an additional 5 dB gain over the existing solution. However, the second solution must perform physical channel estimation based on the code book, which incurs some overhead.

Now, another situation is considered where the base station is equipped with 16 antennas and the terminal is equipped with 1 antenna. The QPSK modulation method is still used. At this time, the spectral efficiency is 6bps/Hz. The following two solutions are considered: the first solution adopts a fixed preprocessing fundamental matrix as described in this embodiment, and the base station uses a preset code book as the preprocessing fundamental matrix according to the channel state information fed back by the terminal. Select a code word from. The codebook adopted for the simulation contains four equally spaced columns selected from a DFT matrix of dimension 16, i.e.

Each column in the above-described matrix represents a code word. A second solution is a conventional multi-carrier spatial modulation system.

Figure 27 shows a comparison of the bit error rate performance of the two solutions described above. It can be seen that compared to conventional solutions, the solution provided by the present disclosure can achieve better performance even if a small code book is adopted. Additionally, the use of a small code book can reduce the overhead of downlink channel estimation. The above shows that, even in FDD mode, the solution provided by this disclosure can achieve significant performance gains at relatively small channel estimation and feedback costs. When the receiving end is equipped with multiple antennas, the code book can be designed to take a row full rank matrix as a code word. The transmitting end selects the code word matrix as the basic preprocessing matrix according to feedback from the receiving end and obtains an extended preprocessing matrix. In this scenario, the flexibility of the expansion operation can be improved by taking the row-wide rank matrix as the preprocessing base matrix, which is advantageous for obtaining better bit error performance with large symbol distance.

Example 10:

This embodiment provides an adaptive parameter adjustment method of the method provided by the present disclosure.

For time-variant channel environments in real communication scenarios, system parameters need to be adjusted in real time according to channel state information to optimize system performance. Regarding the solution provided by this disclosure, the following are channel state information: dimension of the extended preprocessing matrix, dimension of the preprocessing fundamental matrix and selection mode, selection of phase rotation angle, selection of power allocation, and downlink at the transmitting end. It can be adjusted according to the insertion frequency of the pilot used to estimate the equivalent channel, etc. Figure 28 is a schematic diagram showing the generation of a preprocessing matrix based on adaptation parameter selection according to an embodiment of the present disclosure.

If the channel changes rapidly, channel estimation error may lead to inaccuracy in the estimation of the effective channel. In the solution provided by this disclosure, virtual links are created using phase rotation and power allocation. Therefore, channel estimation error may lead to a Euclidean distance between symbols, leading to an increase in bit error rate. The expansion of the preprocessing fundamental matrix can be adjusted, that is, the dimension of the expanded preprocessing matrix W can be an integer N _c ≥N _b , where N _c represents the number of columns of the matrix W, and N _b is the number of columns of the preprocessing fundamental matrix W. The dimension of the extended preprocessing matrix W determines the number of effective transmission links and thus the number of bits transmitted in the spatial domain; therefore, a higher dimension can increase the data rate, and a lower dimension can increase the number of virtual links. The estimation accuracy of the system can be increased by ensuring the difference between symbols and increasing the Euclidean distance between symbols at the receiving end. Adjustment of the dimension of the extended preprocessing matrix W also leads to adjustment of phase rotation and power allocation. In particular, if the channel changes quickly and the channel estimation at the receiving end is inaccurate, the estimation accuracy at the receiving end needs to be increased. Therefore, one can choose an extended preprocessing matrix with low dimensions, large phase rotation angles, and power allocation modes with large differences between power allocation factors. Conversely, if channel conditions are good, the goal may be to increase system data rate. Therefore, one can choose an extended matrix with high dimensionality, small phase rotation angle, and power allocation mode with little difference between the power allocation factors.

For FDD mode, the preprocessing fundamental matrix is selected based on channel state information. Therefore, the number of columns is not determined by the number of transmit antennas or the number of receive antennas. Preprocessing basis matrices with more columns can bring more flexibility to subsequent expansion operations and are beneficial for improving system performance. However, the overhead used for downlink equivalent channel estimation is simultaneously increased. Therefore, when the channel changes quickly or selects a high frequency/time, a preprocessing fundamental matrix with more columns can be used to increase link reliability; Otherwise, a preprocessing basis matrix with fewer columns may be selected to reduce the overhead of downlink equivalent channel estimation.

. 이러한 행렬 중에서, 전처리 기본 행렬의 행의 수 N만이 송신 안테나의 수와 일치해야 한다. N_b 및 N_c는 수신 단으로부터의 피드백에 따라 결정될 수 있다. 예를 들어, N_b는 등가 채널의 채널 가변 속도 또는 랭크와 같은 채널 상태 정보에 의해 결정될 수 있거나 이용 가능한 기준 신호에 의해 결정될 수 있다. N_c는 수신 단에 의해 피드백되는 채널 상태 정보와 수신 단에 의해 필요로 되는 데이터 속도에 의해 결정될 수 있다.The above-mentioned choice of the dimensions of the preprocessing matrix shows that W = W _b W _e , where

. Among these matrices, only the number N of rows of the preprocessing basic matrix must match the number of transmit antennas. N _b and N _c can be determined according to feedback from the receiving end. For example, N _b may be determined by channel state information, such as a channel variable rate or rank of the equivalent channel, or by an available reference signal. N _c can be determined by the channel state information fed back by the receiving end and the data rate required by the receiving end.

Moreover, when the channel changes quickly or a high frequency/time is selected, there may be a large error when only estimating the basic equivalent channel and restoring the extended equivalent channel based on the basic equivalent channel, which may lead to inaccurate channel estimation. do. At this time, it is possible to estimate the channel of some virtual links to correct the estimate of the extended equivalent channel. In this embodiment, the reference signal insertion and channel estimation procedures are as shown in FIG. 29.

In Figure 29, the reference signal is inserted twice. First, after the preprocessing fundamental matrix is generated, preprocessing is performed on reference signal 1 using the preprocessing fundamental matrix. The terminal estimates the equivalent channel according to reference signal 1. Afterwards, the terminal extends the equivalent channel using an extension rule that matches the base station to obtain an estimate of the extended equivalent channel. After obtaining the extended preprocessing matrix, the base station inserts the reference signal 2 second, performs preprocessing on the reference signal 2 using the extended preprocessing matrix, and transmits the preprocessed reference signal 2. The terminal estimates the extended virtual link channel according to the reference signal 2 and corrects the previously obtained estimate of the extended equivalent channel based on the extended virtual link channel. It should be noted that since the second inserted reference signal is only used to correct the estimate of the equivalent channel, the insertion density can be adjusted depending on the reliability of the channel. For example, if current channel conditions are good and data transmission is relatively reliable, the insertion density of the reference signal in the second may be low or insertion may not be necessary. If the channel conditions are poor and data transmission is less reliable, the insertion density of the reference signal in the second needs to be increased.

Eleventh Example:

This embodiment provides an implementation of an open loop system for a single antenna terminal provided by the solution of this disclosure. Assume that the base station already knows the channel state information and that the terminal is equipped with a single antenna. At this time, the base station needs to select a preprocessing fundamental matrix, power allocation, and phase rotation operation to increase the Euclidean distance between symbols at the receiving end. The criterion for selecting the power allocation factor and phase rotation angle is to make the minimum distance between the constellation points in the equivalent constellation at a single antenna receiving end as large as possible through power allocation and phase rotation between different links.

First, the following situation is considered: the base station is equipped with four antennas, and the QPSK modulation method is adopted. At this time, the spectral efficiency is 4bps/Hz. A matrix with 4 rows and 1 column is selected as the preprocessing base matrix. The extended preprocessing matrix is generated through power allocation and phase rotation operations. The selection of power allocation factors and phase rotation angles are shown in Table 4. It should be noted that the generation of the phase rotation angle takes into account the amplitude and phase relationship between the QPSK constellation and the 16QAM constellation.

[Table 4]

Table 4: Selection of power allocation factor and phase rotation angle when the transmitting end is equipped with four antennas

Based on the power allocation factors and phase rotation angles as shown in Table 4, a satisfactory Euclidean distance between symbols can be obtained in the constellation at the receiving end. Figure 30 shows a constellation with and without preprocessing obtained by the receiving end for specific channel realization. The left side of Figure 30 shows the original constellation at the receiving end obtained without preprocessing. Due to the influence of channel time and frequency selective fading, the Euclidean distance between some constellation points of the equivalent constellation at the receiving end is somewhat small, which deteriorates system estimation performance. The right part of Figure 30 shows the constellation at the receiving end when preprocessing is performed. The equivalent constellation at the receiving end is similar to the rotated 16QAM constellation. The average minimum Euclidean distance is increased. Accordingly, system estimation performance is improved. Figure 31 shows a comparison of the bit error rate performance of the two solutions described above. It can be seen that due to the increase in the distance between symbols, the solution including preprocessing has improved bit error rate performance.

Then, another situation is considered: the base station is equipped with 16 antennas, and the QPSK modulation scheme is still used. At this time, the spectral efficiency is 6bps/Hz. A vector with 16 rows and 1 column is randomly selected as the preprocessing base matrix. The selection of power allocation factors and phase rotation angles are shown in Table 5.

[Table 5]

Table 5: Selection of power allocation factors and phase rotation angles when the base station is equipped with 16 antennas.

Figure 32 is a schematic diagram showing an equivalent constellation with and without preprocessing at the receiving end for specific channel realization. As shown by the left constellation in Figure 32, in the case without preprocessing, due to the influence of the channel, the Euclidean distance between some points in the equivalent constellation at the receiving end is rather small, degrading the system bit error rate performance. I order it. However, as shown in the right part of Figure 32, after preprocessing, the equivalent constellation at the receiving end is similar to the rotated constellation of 16QAM, where there is a certain Euclidean distance between each pair of constellation points. is guaranteed. Therefore, the minimum Euclidean distance between symbols is greatly increased, and the bit error performance of the overall system is improved.

Figure 33 is a schematic diagram showing a comparison of the bit error rate performance of the two solutions described above when the base station is equipped with 16 antennas. As the data rate increases, the number of constellation points in the equivalent constellation at the receiving end also increases. Therefore, the system is susceptible to interference by noise. After preprocessing, the minimum Euclidean distance between constellation points is increased. Accordingly, the system has improved noise resistance and the bit error rate performance of the overall system is improved. From Figure 33, it can be seen that the bit error rate performance of the system is improved after the preprocessing method provided by the present disclosure is applied.

It should be noted that in this embodiment, a constellation similar to the QAM modulation scheme is generated at the receiving end through power allocation and phase rotation. Other types of constellations can also be created by adjusting the power allocation and phase rotation values. However, the basic criterion is to make the minimum Euclidean distance between the constellation points of the equivalent constellation at the receiving end as large as possible.

Example 12:

This embodiment applies the solution of this disclosure to reduce reference signal overhead. Assume that the base station has four transmitting antennas, the receiving end has one receiving antenna, and the base station does not know channel state information. The preprocessing basic matrix is defined as:

The rank of the preprocessing base matrix is 3, i.e. the column vectors of the matrix are not linearly correlated. The matrix is expanded through a linear combination of the columns of the matrix, that is, the first three columns of the expanded preprocessing matrix are the three columns of the preprocessing base matrix W _b , and the fourth column is w ₄ =w ₁ -w ₂ +w It is ₃ . Therefore, the extended preprocessing matrix is obtained as follows:

The extended equivalence matrix is:

There are still four Donga links. To transmit spatial modulation symbols as described in the above-described embodiments, one of the four equivalent links is activated during each transmission. Information is transmitted via the active link and the index of the transmitted symbol.

Since the column rank of the preprocessing basic matrix is 3, only three reference signals using orthogonal resources are required to complete the estimation of the basic equivalent channel. Then, through expansion of the extended matrix W _e , the extended equivalent channel can be obtained, and estimation of the transmitted signal can be implemented.

The above-described embodiment shows that the preprocessing basis matrix with the corresponding column rank can be designed according to the amount of available reference signals or the amount of resources available for transmitting the reference signal. The extended preprocessing matrix can be generated through a simple linear combination of the columns of the preprocessing base matrix. It is possible to achieve high data rates with relatively low reference signal overhead. In this way, a tradeoff between the overhead of the reference signal and the data rate can be obtained. Considering that the length of the reference signal is generally a power of 2, the occupied orthogonal resources are also a power of 2. If the required reference signal does not meet these conditions, unused reference signal resources can be used to transmit data to reduce overhead.

The above-described embodiment is taken as an example. Assume that the length of the reference signal is 4. Although the number of reference signals required is 3, four orthogonal resources are still required to transmit the reference signals. Therefore, the overhead of the reference signal does not change. At this time, orthogonal resources that are not used to transmit the reference signal can be used to transmit data, and the data can be differentiated from the reference signal by orthogonal cover code technology to reduce the overhead of the reference signal.

According to the above-described signal transmission method based on multi-carrier spatial modulation, an embodiment of the present disclosure provides a transmission device as shown in FIG. 34. The transmission device includes a first preprocessing basic matrix calculation module, a first preprocessing matrix expansion module, a first reference signal transmission module and a first data transmission module; here,

The first pre-processing fundamental matrix calculation module is set to determine the pre-processing fundamental matrix;

The first preprocessing matrix expansion module is configured to expand the preprocessing basic matrix to obtain an expanded preprocessing matrix;

The first reference signal transmission module is configured to perform preprocessing on the first reference signal with a preprocessing basic matrix and transmit the preprocessed first reference signal to the receiving device;

The first data transmission module performs symbol mapping and spatial modulation on the bit stream to be transmitted, performs preprocessing on the symbols obtained after spatial modulation with an extended preprocessing matrix, and performs multi-carrier modulation on the preprocessed symbols. and is set to transmit the symbol to the receiving device.

According to the above-described signal transmission method in a multi-user system based on multi-carrier spatial modulation, an embodiment of the present disclosure provides a transmission device as shown in FIG. 35. The transmission device includes a second preprocessing basic matrix calculation module, a second preprocessing matrix expansion module, a second reference signal transmission module and a second data transmission module; here,

The second preprocessing basic matrix calculation module is configured to select a preprocessing basic matrix for each terminal according to the channel state information;

the second preprocessing matrix expansion module is configured to expand the preprocessing basic matrix of each terminal to obtain a corresponding expanded preprocessing matrix;

The second reference signal transmission module is configured to perform preprocessing on the reference signal with a preprocessing basic matrix and transmit the preprocessed reference signal to the corresponding terminal; Reference signals transmitted to different terminals use orthogonal resources;

The second data transmission module performs symbol mapping and spatial modulation on the bit stream of each terminal, performs preprocessing on the spatial modulation symbol using the corresponding extended preprocessing matrix, and preprocesses the preprocessed symbol of each terminal. is set to combine, perform multi-carrier modulation on the combined symbol, and transmit the symbol.

According to the above-described signal transmission method based on multi-carrier spatial modulation, an embodiment of the present disclosure provides a receiving device as shown in FIG. 36. The receiving device includes a receiving module, a basic equivalent channel estimation module, an extended equivalent channel estimation module and a demodulation module; here,

The receiving module is configured to receive a first reference signal and data;

The basic equivalent channel estimation module is set to estimate the basic equivalent channel based on the first reference signal;

the extended equivalent channel estimation module is configured to expand the basic equivalent channel using a method consistent with the method used by the transmitting device to expand the preprocessing basic matrix to obtain an estimate of the expanded equivalent channel;

The demodulation module is set to demodulate data according to an estimate of the extended equivalent channel to obtain the original data.

In one embodiment, the receiving module of the receiving device further receives a second reference signal;

The extended equivalent channel estimation module further corrects the estimate of the extended equivalent channel according to the second reference signal.

Example 13:

In this embodiment, a method of combining antenna port grouping and preprocessing based on spatial modulation will be described.

Assume that multiple UEs are served within one cell. To serve multiple UEs in a broadcast manner, the methods of embodiments 1 to 5 can be applied. Preprocessing methods can be applied to improve performance. In particular, the antenna grouping is based on the effective antenna ports generated by preprocessing. The basic procedure is explained as follows.

1. The UE estimates downlink channel state information through CSI-RS or CRS and reports the corresponding channel state information to the BS by using quantified CSI or codebook-based CSI feedback. At this stage, the base station can obtain downlink CSI from multiple UEs. Another way to obtain downlink CSI is to estimate it over the uplink channel by using the channel correlation in TDD mode.

2. According to downlink CSI from multiple UEs, UEs with similar downlink channel state information are grouped as one group. For one UE group, one downlink CSI is used to calculate the preprocessing matrix. One possible way to obtain downlink CSI for one UE group is to average all downlink CSI for UEs in this UE group.

3. Based on the downlink CSI for the UE group, the preprocessing matrix is calculated based on the method proposed in Examples 1 to 5. In particular, a two-step method is used, which includes calculation of a basic preprocessing matrix based on the downlink CSI for a UE group and expansion using a predefined expansion method. In this step, an effective antenna port corresponding to an effective link is formed.

4. Based on the effective antenna ports, antenna port grouping can be performed. Considering that the preprocessing procedure can be transparent to the UE, the only thing that needs to be notified to the UE is the antenna port grouping information, and the notification method proposed in the previous embodiment can be applied.

5. Broadcast information is transmitted to multiple UEs in one group based on layered spatial modulation.

Note that the above-described layering of data transmitted in the previous embodiment can still be applied in a preprocessing based scheme. Additionally, the channel frequency selectivity as well as the channel time selectivity will determine the parameters of the preprocessing method as demonstrated in the previous examples.

If there is no UE grouping procedure or there is no downlink CSI of multiple UEs, a random fundamental matrix or a fixed fundamental matrix can be used to generate the preprocessing matrix. In this way, feedback with some performance loss is not required.

The above is only a preferred embodiment of the present application and does not limit the present application, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall fall within the scope claimed by the present application.

Claims (20)

In a method performed by a base station of a wireless communication system,
dividing a plurality of links into at least two groups;
Transmitting link grouping setting information to the terminal;
layering data flows to be transmitted according to the grouping of links;
performing spatial modulation on the layered data flow;
performing multi-carrier modulation on the spatially modulated signal; and
It includes transmitting the multi-carrier modulated signal to a terminal;
Splitting the plurality of links into at least two groups includes further performing the splitting until each group contains only one link or the setting requirements for link grouping are met,
The method wherein the link grouping setting information is information about the links included in each group. According to claim 1,
The step of layering the data flow to be transmitted according to the grouping of the links includes:
Transmitting primary data using a group of a first layer, and transmitting secondary data using each group of a layer different from the first layer based on a previous layer,
The method characterized in that the auxiliary data includes at least one of extended data based on the basic data, redundant information of data of a previous layer, and a combination of the extended data and the redundant information. According to claim 1,
The method for dividing the plurality of links into the groups is characterized in that links having a correlation index greater than a setting threshold are assigned to one group. According to claim 1,
estimating a correlation index between links according to information from the receiver; and
further comprising dynamically adjusting the number of links and the grouping of links,
and the information from the receiver includes channel state information fed back from the receiver and/or a sounding reference signal transmitted by the receiver via an uplink channel to the transmitter. According to claim 1,
allocating users having the same link grouping setting information into one group; and
The method further comprising performing a broadcast service on the same time-frequency resource for the users in the same group. In a method performed by a terminal of a wireless communication system,
Receiving link grouping setting information from a base station;
Obtaining grouping of links included in each group and information on the links according to the link grouping setting information; and performing layered detection on received data according to the grouping of links;
The step of performing layered detection on received data according to the grouping of links includes detecting data transmitted from all layers according to channel state information of each link, and the number of layers to be maintained according to setting criteria. Including the step of determining,
Wherein each group is divided until each group contains only one link or the setting requirements for link grouping are met. According to clause 6,
The setting criterion includes comparing an estimated signal-to-noise ratio of detected data from each layer with a preset signal-to-noise ratio threshold, and, if higher than the signal-to-noise ratio threshold, sending the data to the corresponding layer. maintaining and performing subsequent processing, otherwise not performing said subsequent processing; or the setting criteria comprises determining, by a transmitter, independently for each layer independently, whether to retain data of a corresponding layer for each receiver depending on whether a CRC check added by the transmitter passes. How to feature. According to clause 6,
Detecting data of each layer according to channel state information of each group; and
The method further comprising comparing the estimated signal-to-noise ratio of the data detected from each layer with a preset signal-to-noise ratio threshold. According to clause 8,
If the signal-to-noise ratio is higher than the threshold, performing subsequent detection of data of the next layer, and
Otherwise, the method further comprises terminating the detection. According to clause 6,
Receiving a reference signal according to the grouping of the links; and
The method further comprising performing channel estimation. In the base station of a wireless communication system,
Transmitter and receiver; and
It is connected to the transceiver, divides a plurality of links into at least two groups, transmits link grouping setting information to the terminal, stratifies data flows to be transmitted according to the grouping of the links, and provides information on the stratified data flows. Perform spatial modulation, perform multi-carrier modulation on the spatially modulated signal, and transmit the multi-carrier modulated signal to the terminal, and each group includes only one link or the setting requirements for link grouping are met. It includes a control unit that further performs the division until
The link grouping setting information is a base station characterized in that the link information included in each group. According to claim 11,
The control unit,
transmitting primary data using a group of a first layer, and transmitting secondary data using each group of a layer different from the first layer based on a previous layer;
The auxiliary data includes at least one of extended data based on the basic data, redundant information of data of a previous layer, and a combination of the extended data and the redundant information. According to claim 11,
A base station characterized in that the criterion for dividing the plurality of links into the groups is to allocate links with a correlation index greater than a setting threshold to one group. According to claim 11,
The control unit,
further comprising estimating a correlation index between links according to information from the receiver, and dynamically adjusting the number of links and the grouping of links;
The base station, characterized in that the information from the receiver includes channel state information fed back from the receiver and/or a sounding reference signal transmitted by the receiver to the transmitter through an uplink channel. According to claim 11,
The control unit,
Allocating users with the same link grouping setting information to one group, and performing a broadcast service on the same time-frequency resource for the users in the same group. In the terminal of a wireless communication system,
Transmitter and receiver; and
It is connected to the transceiver, receives link grouping setting information from the base station, obtains grouping of links included in each group and information on the link according to the link grouping setting information, and receives information on the link according to the grouping of the link. a control unit that performs layered detection of data, detects data transmitted from all layers according to channel state information of each link, and determines the number of layers to be maintained according to a setting standard;
A terminal, characterized in that each group is divided until each group includes only one link or the setting requirements for link grouping are met. According to claim 16,
The setting criteria compares the estimated signal-to-noise ratio of detected data from each layer with a preset signal-to-noise ratio threshold, and, if higher than the signal-to-noise ratio threshold, retains the data in the corresponding layer. and perform subsequent processing, otherwise, do not perform said subsequent processing; Or, the setting criterion is a terminal characterized in that the transmitter determines whether to maintain the data of the corresponding layer for each receiver independently for each layer depending on whether a CRC check added by the transmitter passes. . According to claim 16,
The control unit,
The terminal further comprising detecting data of each layer according to the channel state information of each group, and comparing the estimated signal-to-noise ratio of the data detected from each layer with a preset signal-to-noise ratio threshold. . According to clause 18,
The control unit,
If the signal-to-noise ratio is higher than the threshold, performing subsequent detection of data of the next layer, and otherwise terminating the detection. According to claim 16,
The control unit,
A terminal further comprising receiving a reference signal according to the grouping of the links, and performing channel estimation.

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