CN107026681B - Signal sending method, receiving method, transmitter and receiver - Google Patents

Signal sending method, receiving method, transmitter and receiver Download PDF

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CN107026681B
CN107026681B CN201610069071.6A CN201610069071A CN107026681B CN 107026681 B CN107026681 B CN 107026681B CN 201610069071 A CN201610069071 A CN 201610069071A CN 107026681 B CN107026681 B CN 107026681B
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layer
data
transmitter
grouping
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CN107026681A (en
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钱辰
喻斌
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Samsung Electronics Co Ltd
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0404Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas the mobile station comprising multiple antennas, e.g. to provide uplink diversity
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems
    • H04B7/0417Feedback systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems
    • H04B7/0426Power distribution
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0602Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
    • H04B7/0608Antenna selection according to transmission parameters
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0602Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
    • H04B7/0608Antenna selection according to transmission parameters
    • H04B7/061Antenna selection according to transmission parameters using feedback from receiving side
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0697Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using spatial multiplexing

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Transmission System (AREA)

Abstract

The application provides a signal sending method, which comprises the following steps: the transmitter transmits link grouping configuration information; the link grouping configuration information is information of links contained in each group after the link is divided into at least two groups; the transmitter carries out layering on data streams to be transmitted according to the grouping of the link; the transmitter performs spatial modulation on the layered data stream; the transmitter carries out multi-carrier modulation on the signals after the space modulation; the transmitter transmits the multicarrier modulated signal. The application also provides a signal receiving method, a transmitter and a receiver. The method and the device provide different protection degrees for different data streams by utilizing the characteristics of the spatial modulation system, so that users with different channel conditions can obtain services with different qualities.

Description

Signal sending method, receiving method, transmitter and receiver
Technical Field
The present application relates to the field of wireless communication technologies, and in particular, to a signal transmitting method, a signal receiving method, a transmitter, and a receiver.
Background
The rapid development of the information industry, particularly the growing demand from the mobile internet and internet of things (IoT), presents an unprecedented challenge to future mobile communication technologies. As can be expected from international telecommunication union ITU's report ITU-R M. [ imt. beyond 2020.TRAFFIC ], by 2020, mobile TRAFFIC will increase by nearly 1000 times in relation to 2010 (era 4G), and the number of user equipment connections will also exceed 170 billion, and will be even more dramatic as the vast number of IoT devices gradually permeates into mobile communication networks. To address this unprecedented challenge, the communications industry and academia have developed an extensive fifth generation mobile communications technology research (5G) facing the 2020. Future 5G frameworks and overall goals are currently discussed in ITU's report ITU-R M [ imt.vision ], wherein the 5G demand landscape, application scenarios and various important performance indicators are specified. For the new requirements in 5G, ITU's report ITU-R M. [ imt. user TECHNOLOGY TRENDS ] provides relevant information for 5G TECHNOLOGY TRENDS, aiming at solving significant problems of significant improvement of system throughput, consistency of user experience, scalability to support IoT, latency, energy efficiency, cost, network flexibility, support of emerging services, and flexible spectrum utilization.
Multiple-input Multiple-output (MIMO) technology is an important means to improve the spectral efficiency of a system. Since the mimo technology can effectively improve the system data rate and improve the system link stability, it has been widely applied in the broadcast audio and Video fields and in civil communication systems, such as Long Term Evolution (LTE) system corresponding to the Evolved Universal Radio Access (E-UTRA) protocol established by the third Generation Partnership Project (3rd Generation Partnership Project, 3GPP), second Generation Digital Video Broadcasting (DVB) in europe, and IEEE802.16 worldwide Interoperability for Microwave Access (WiMAX), etc. The MIMO technology can provide a spatial diversity gain and a spatial multiplexing gain to a system by establishing communication links between different antennas at a transmitting and receiving end. By transmitting the same data on different links, the MIMO technology improves the reliability of the transmitted data, thereby obtaining diversity gain; by transmitting different data in different links, the MIMO technology can improve the spectral efficiency of the system without increasing the transmission bandwidth, thereby improving the transmission data rate. Through the channel state information of the transmitting terminal, the MIMO technology can also serve a plurality of users at the same time and the same frequency through coding, and the integral frequency spectrum efficiency of the system is improved. At present, the MIMO technology, as a key technology, can well support the requirement of Mobile Broadband (MBB) service in the 4G era. In 5G, the requirements of spectrum efficiency, energy efficiency and data rate are further improved, and the existing MIMO technology is difficult to meet the requirement of great improvement of the data rate. Therefore, evolution of MIMO technology: massive MIMO has received extensive attention from both academic and industrial circles. By configuring antennas far more than the number of users at the transmitting end, the large-scale MIMO technology can obtain a larger array processing gain (thinner beam) and a larger spatial degree of freedom, and can completely distinguish users by simple linear operation, thereby further greatly improving the spectrum efficiency and the energy efficiency. However, in practical application scenarios, the MIMO technology and the massive MIMO technology also encounter some problems, such as: whether the MIMO technique is effective and reliable depends on whether the transmitting end can obtain accurate channel state information. If the channel state information of the transmitting end is not accurate enough, the system gain is reduced significantly. Current MIMO technology relies on channel estimation and feedback based on reference signals, and when the number of antennas increases, the overhead of reference signals and feedback will severely reduce the spectral efficiency of the system. 2. The requirement for synchronization between antennas is strict. 3. The receiving end needs to deal with interference between the antennas. 4. Although multi-user MIMO can improve the spectrum efficiency of the entire cell, it is not sufficient to improve the spectrum efficiency of a single user.
Spatial Modulation (SM), a branch of MIMO technology, has recently gained wide attention in academia. SM techniques use a fraction of the information bits to select the transmit antennas, using only one antenna per transmission. By taking the antenna index as an additional carrier for transmitting information, the three-dimensional constellation diagram is constructed on the basis of the traditional two-dimensional constellation diagram, so that higher frequency spectrum efficiency than a single-antenna system can be obtained. Meanwhile, the SM technology also solves some problems of the conventional MIMO technology. For example, because only a single antenna is used for each transmission, the SM technology does not require the receiving end to perform complex synchronization between antennas and elimination of interference between links, thereby simplifying the processing of the receiving end; the SM technology can increase the spectrum efficiency of a single user, so that the SM technology is more suitable for some scenes needing to improve the data rate of the single user; the SM technology does not need pre-coding at a sending end, so that a receiving end does not need to perform feedback; the transmitting end only needs one radio frequency link, and the expense of the transmitting end is greatly reduced. Although the advantage of a single radio frequency link is lost in the multi-carrier-based SM technology, the distribution of time-frequency two-dimensional resources provides a higher degree of freedom for a system, and meanwhile, the SM technology has better robustness to frequency selective fading caused by multipath.
The advantages of SM technology have made it a great deal of interest in communications research. The characteristics that channel feedback is not needed, and the number of receiving end antennas is not required make the antenna transmission method particularly suitable for transmitting broadcast data or data in an open loop mode. In order to expand the application of the spatial modulation technology in 5G and exert the advantages of the spatial modulation technology, the characteristics of the spatial modulation technology need to be continuously discovered, and the schemes of the spatial modulation technology under different application scenes are perfected.
Disclosure of Invention
The technical problem to be solved by the present invention is that differentiated services cannot be provided for users with different channel conditions in the transmission of the broadcast data of the cellular system. Therefore, the application provides a signal sending method, a signal receiving method, a transmitter and a receiver, which provide different protection degrees for different data streams by using the characteristics of a spatial modulation system, so that users with different channel conditions can obtain services with different qualities.
The invention provides a signal sending method, which comprises the following steps:
the transmitter transmits link grouping configuration information; the link grouping configuration information is information of links contained in each group after the link is divided into at least two groups;
the transmitter carries out layering on data streams to be transmitted according to the grouping of the link;
the transmitter performs spatial modulation on the layered data stream;
the transmitter carries out multi-carrier modulation on the signals after the space modulation;
the transmitter transmits the multicarrier modulated signal.
Preferably, the dividing the link into at least two groups includes: dividing all available links into at least two packets, the resulting packets being packets in a first layer; dividing each group in the first layer into at least two groups, and taking the obtained group as each group in the second layer; and so on until each packet contains only one link or the set link packet requirements are met.
Preferably, the layering, by the transmitter, the data stream to be transmitted according to the packet of the link includes:
transmitting base data with packets in a first layer, transmitting auxiliary data on a previous layer basis with packets in layers other than the first layer; wherein the assistance data comprises at least one of: based on the extension data above the basic data, the redundant information of the previous layer data, and the combination of the extension data and the redundant information.
Preferably, the criteria for grouping links are: and grouping the links with the relevance indexes larger than a set threshold value.
Preferably, the method further comprises: the transmitter estimates the correlation index between links according to the information from the receiver and dynamically adjusts the number of links and the grouping of the links according to the correlation index; the information from the receiver comprises channel state information fed back by the receiver and/or a sounding reference signal sent to the transmitter by the receiver through an uplink channel.
Preferably, the method further comprises: and dividing users with the same link grouping configuration information into a group, and performing broadcast service on the same time-frequency resource for the users in the same group.
Preferably, the method further comprises:
and after preprocessing the signal after spatial modulation, performing multi-carrier modulation and transmitting.
Preferably, the pretreatment comprises: power adjustment is performed on the link and/or phase adjustment is performed on the link.
Preferably, the power adjusting the link includes: under the condition of keeping the transmission power unchanged, adjusting the average transmission power of each group in the first layer to ensure that each group has different average transmission power; under the condition of keeping the average transmitting power of each group in the first layer unchanged, adjusting the average transmitting power of each group in the second layer to ensure that each group in the second layer has different average transmitting power; and repeating the steps until the average transmitting power of each packet of the lowest layer is adjusted.
Preferably, the criterion for adjusting the average transmission power of each layer packet is: the power adjustment amount of the latter layer is not larger than that of the former layer.
Preferably, the phase adjusting the link includes: the rotating phases are randomly selected for the links of the respective packets of the lowest layer, the intervals of the rotating phases of the respective links belonging to different packets are disjoint, and adjacent rotating phase intervals are selected for the links of the respective packets belonging to the same packet in the previous layer.
Preferably, constellation point symbols in the spatial modulation are used to transmit the lowest layer data, or other auxiliary or redundant information.
Preferably, the method further comprises: the transmitter transmits the reference signal according to the packet of the link.
Preferably, the transmitting the reference signal according to the packet of the link by the transmitter includes: the transmitter transmits the same reference signal sequence using the same time-frequency resources for the links belonging to the same group for estimation of the equivalent channel coefficients of the corresponding group.
Preferably, if the spatially modulated signal is pre-processed, then multi-carrier modulated and transmitted, before transmitting the reference signal, the method further includes: the reference signal is subjected to the preprocessing.
Preferably, the method further comprises: and partitioning the layered data of each layer, and adding an independent Cyclic Redundancy Check (CRC) code to the data of each layer in each data block.
Preferably, the transmitter transmits the link number information and the link grouping configuration information in at least one of a physical broadcast channel, a downlink physical control channel and a physical downlink shared channel.
Preferably, the transmitter transmits a physical broadcast channel, a downlink physical control channel or a physical downlink shared channel to which an additional field is added, wherein the additional field is used for indicating the link number information and the link grouping configuration information.
Preferably, the transmitter transmits the link number information using CRC check masks in the physical broadcast channels, where a transmission mode of each physical broadcast channel corresponds to at least two CRC check masks, and each CRC check mask corresponds to one link number information; the transmission mode of the physical broadcast channel comprises a single antenna port transmission mode, a double antenna port transmission diversity mode and a four antenna port transmission diversity mode;
the transmitter transmits a physical broadcast channel, a downlink physical control channel or a physical downlink shared channel to which an additional field for indicating link grouping configuration information is added.
The present application also provides a transmitter, comprising:
a configuration module for transmitting link grouping configuration information; the link grouping configuration information is information of links contained in each group after the link is divided into at least two groups;
the data layering module is used for layering the data stream to be transmitted according to the grouping of the link;
the spatial modulation module is used for carrying out spatial modulation on the layered data stream;
the multi-carrier modulation module is used for carrying out multi-carrier modulation on the signals after the spatial modulation;
and the sending module is used for sending the signal after the multi-carrier modulation.
The application also provides a signal receiving method, which comprises the following steps:
the receiver receives link grouping configuration information;
the receiver acquires the grouping of the link and the information of the link contained in each grouping according to the link grouping configuration information;
the receiver performs hierarchical detection on the received data according to the packets of the link.
Preferably, the performing, by the receiver, hierarchical detection on the received data according to the packet of the link includes:
the receiver detects the sending data of all layers according to the channel state information of each link, and determines the reserved layer number according to a set criterion; wherein the set criteria include: comparing the signal-to-noise ratio estimation of each layer of detected data with a preset signal-to-noise ratio threshold, if the signal-to-noise ratio is higher than the threshold signal-to-noise ratio, retaining the data of the corresponding layer and carrying out subsequent processing, otherwise, not carrying out subsequent processing; or, the set criteria include: the transmitter decides for each receiver whether to retain the data of the corresponding layer according to whether CRC check passed or not added by the transmitter for each layer data individually.
Preferably, the method further comprises: and the receiver detects data of each layer by layer according to the channel state information of each group, compares the signal-to-noise ratio estimation of the detected data of each layer with a preset signal-to-noise ratio threshold value, continues the detection of the data of the next layer if the signal-to-noise ratio estimation is higher than the signal-to-noise ratio threshold value, and stops the detection if the signal-to-noise ratio estimation is not higher than the signal-to-noise ratio threshold value.
Preferably, the method further comprises: the receiver receives the reference signal from the packet of the link and performs channel estimation.
The present application also provides a receiver comprising:
a configuration information receiving module for receiving link grouping configuration information;
the grouping confirmation module is used for acquiring the grouping of the link and the information of the link contained in each grouping according to the link grouping configuration information;
and the detection module is used for carrying out layered detection on the received data according to the grouping of the link.
The present invention provides a method and apparatus for providing a layered service to a user receiving a broadcast service using multiple antennas. By adopting the invention, the user with better channel condition can receive more or more reliable data, and the user with poorer channel condition can also obtain basic service, thereby avoiding the problem that the service quality in the traditional broadcast service is determined according to the user with the worst channel condition, and providing differentiated service for the users with different channel conditions.
Drawings
Fig. 1 is a block diagram of a multi-carrier spatial modulation system;
FIG. 2 is a diagram of a conventional MBSFN system;
fig. 3 is a schematic diagram of a possible link grouping manner according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a bit grouping according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating bit error rate comparison of different groups when a receiving end is equipped with four receiving links according to a first embodiment of the present invention;
fig. 6 is a schematic diagram illustrating comparison of different packet error rate performances when a receiving end is equipped with two links according to an embodiment of the present invention;
fig. 7 is a schematic diagram illustrating performance comparison of different packet error rates when a receiving end is equipped with two links and there is high correlation between the links according to an embodiment of the present invention;
FIG. 8 is a schematic diagram illustrating a data layering method according to an embodiment of the present invention;
FIG. 9 is a diagram illustrating inter-link power allocation according to a second embodiment of the present invention;
fig. 10 is a schematic operation flow chart of a third embodiment of the present invention, in which a multi-carrier spatial modulation technique supporting layered transmission is adopted;
fig. 11 is a schematic diagram illustrating a manner of transmitting link number information and link grouping configuration information according to a third embodiment of the present invention;
fig. 12 is a schematic diagram illustrating a manner of using CRC masks to carry link number information according to a third embodiment of the present invention;
fig. 13 is an exemplary diagram of an RS for packet transmission in the fourth embodiment of the present invention;
fig. 14 is a schematic resource allocation diagram of a RS for packet transmission in the fourth embodiment of the present invention;
fig. 15 is a schematic diagram of grouping users according to a fifth embodiment of the present invention;
fig. 16 is a schematic flowchart of grouping user groups according to a fifth embodiment of the present invention;
fig. 17 is a schematic flowchart of a multi-carrier spatial modulation technique based on layered transmission according to a fifth embodiment of the present invention;
FIG. 18 is a block diagram of a preferred transmitter according to the present invention;
fig. 19 is a block diagram of a preferred receiver according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below by referring to the accompanying drawings and examples.
The spatial modulation technique utilizes the antenna index of the transmission data as an additional carrier of information, and can obtain higher spectral efficiency under the same bandwidth compared with a single-antenna system. Compared with the traditional multi-antenna system, the spatial modulation technology has the following advantages: 1. because only one transmitting antenna is used in each data transmission, the receiving end does not need to carry out synchronization among the antennas; 2. only a single transmitting antenna is suitable, inter-link interference cannot be generated, and a receiving end does not need to use a high-complexity equalization algorithm to eliminate the inter-link interference; 3. only a small number of radio frequency channels are needed, the problem of high energy consumption caused by high number of radio frequency channels can be remarkably reduced, namely, the spatial modulation is a system with high energy efficiency; 4. the spatial modulation system can still work when the number of the transmitting antennas is larger than that of the receiving antennas. In addition, the same spectrum efficiency can be realized by the combination of different antenna numbers and modulation modes, so that the spatial modulation enables the parameters of the system to be more flexible. A spatial modulation system combining with multi-carrier technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and the like performs spatial modulation on a frequency domain equivalent multi-antenna channel including multi-carrier modulation, an actual physical channel and multi-carrier demodulation, and although the advantage of a small number of radio frequency channels is lost, a larger degree of freedom is obtained in the problems of resource allocation, pilot allocation and the like, and the compatibility with the standard is also better.
The block diagram of the multi-carrier spatial modulation technique is shown in the left dashed box of fig. 1, where N is the number of antennas at the transmitting end, and Q is 2 as the modulation order usedBWhere B is the number of bits mapped to one symbol. The basic processing flow is as follows: sending a data stream log2(NQ)=log2(N) + B bits into one group, top log2(N) bits determine the stream index for transmitting data, andthe B bits are mapped to one QAM symbol. Taking N-2 and B-2 as an example, the mapping relationship between spatial modulation bits and symbols is shown in table 1. In table 1, the antenna index indicates an antenna index currently used for transmitting data. In the transmitted bit sequence, the first bit is used to determine the antenna index, and the last two bits are used to determine the transmitted symbol. After the spatial modulation symbols are obtained, Inverse Fast Fourier Transform (IFFT) is performed on all N data streams to obtain data streams transmitted on N transmit antennas.
Table 1: bit-to-symbol mapping relationships
Figure BDA0000919361890000071
Figure BDA0000919361890000081
The block diagram of the receiving end of the spatial modulation technique using the OFDM technique is shown in the right dotted line box of fig. 1, and the receiving end is configured with M antennas. After receiving the received signal, the receiving end performs Fast Fourier Transform (FFT) on the data stream of each receiving antenna to obtain a frequency domain signal. Setting a frequency domain equivalent channel matrix including an originating IFFT, an actual physical channel and a receiving end FFT as H ∈ CM×NThen the corresponding channel model can be written as:
y=Hx+n
h is a frequency domain equivalent channel matrix represented by an M-by-N dimensional complex matrix, M is the number of equivalent receiving links, N is the number of equivalent transmitting links, CM×NRepresenting a matrix of MxN dimensions over a complex field, y ∈ CM×1For the received vector after FFT, x ═ eisj∈CN×1For the transmitted spatial modulation symbol vector, n ∈ CM×1Is a noise vector. Vector ei=[0,...,0,1,0,...,0]T∈CN×1Of which only the ith element is 1 and the remaining elements are 0, indicates that only the ith antenna is used for data transmission according to the transmission bit, [ 2 ]]TRepresenting the transpose of the vector. SymbolsjA symbol selected from a constellation mapping, such as Quadrature Amplitude Modulation (QAM), Pulse Amplitude Modulation (PAM), or Phase Shift Keying (PSK) symbol set, according to a transmission bit. Thus, the received symbols can be abbreviated as:
y=hisj+n
wherein h isi∈CM×1Is the ith column of matrix H.
The receiving end adopts the following maximum likelihood detection algorithm to detect the transmitted symbols:
Figure BDA0000919361890000082
deriving estimates of transmit antenna indices
Figure BDA0000919361890000083
And estimation of received symbols
Figure BDA0000919361890000084
Then, an estimated value of the transmitted bit stream can be obtained according to the mapping rule of bits to symbols.
In addition to the above-described Spatial Modulation system in which only one link transmits data at a time, a Generalized Spatial Modulation (GSM) system activates a subset of all links at a time and uses an index of the subset as a carrier for transmitting information, and different links can transmit the same data, so as to improve the reliability of the system; or transmit different data to increase the data rate of the system. This is considered herein as a form of spatial modulation.
The existing literature [ Bit Error Probability of SM-MIMO Over Generalized facing Channels ] and simulation results show that, compared with a conventional open-loop MIMO system (e.g., Space Frequency Block Code (SFBC) or V-BLAST system), a multicarrier Spatial modulation system can better exploit the receive diversity provided by a receiving antenna, and can achieve a performance obviously superior to that of the conventional open-loop system for a user equipped with multiple receiving antennas. The nature of the spatial modulation system that does not require Channel feedback makes the technique particularly well suited for Broadcast channels, such as the Physical Multicast Channel (PMCH) that provides multimedia Broadcast/Multicast Service (MBMS).
In the existing LTE-a, an MBMS service is provided in a Multimedia Broadcast Single Frequency Network (MBSFN) manner, as shown in fig. 2. In the figure, a plurality of base stations simultaneously transmit the same broadcast information at the same frequency, and a user can obtain a Signal-to-interference plus noise ratio (SINR) higher than that of a single cell system by using signals from different base stations as multipath components, so that the method is very suitable for a moving user and a cell edge user.
The characteristics of the broadcast channel that it is difficult to utilize originating channel state information and the types of users that are simultaneously served are diverse make it difficult to apply the conventional MIMO technology, so the physical layer multicast channel (PMCH) in the existing standard uses only single antenna transmission. In this case, the multicarrier spatial modulation technique that does not require channel state information feedback can provide a higher data rate than single-antenna transmission, as well as utilizing multiple antennas at the base station side. By combining MBSFN, higher reliability can be obtained than single cell multicarrier spatial modulation. There is therefore a great potential for using spatial modulation techniques for PMCH.
Currently, in MBMS transmission, a transmission mode can only be designed for a worst channel, so that it is difficult for a user with good channel conditions to obtain a better data rate, thereby limiting the overall achievable performance of the system. In the method and the device, the characteristics of the multi-carrier spatial modulation technology are combined to provide services with different qualities for users with different channel states, so that the user experience is improved, and the total system performance of the broadcast channel is improved. The basic idea of the application is to utilize the correlation between links to layer the links, so that data transmitted at different layers can obtain different protections. When the receiver detects data, the detected data layer is selected according to the self channel condition. Therefore, users with poor channel conditions can still obtain the underlying data, while users with good channel conditions can detect more data layers, thereby obtaining higher data rate.
The first embodiment is as follows:
in this embodiment, we describe a multicarrier spatial modulation system that provides layered transmission with specific system parameter settings. It is assumed that the base station is equipped with 16 transmit antennas, i.e. at most 16 links can be activated simultaneously. The available time-frequency resources are in units of Physical Resource Blocks (PRBs) specified in LTE, and one PRB is composed of 12 subcarriers on 14 adjacent OFDM symbols. The number of system subcarriers is 256, and the number of available subcarriers is 120, i.e. 10 subcarriers consecutive in the frequency domain are considered. To verify the possibility of hierarchical transmission using link correlation, in this embodiment, Space Shift Keying (SSK) modulation is used, that is, one link is activated at a time, but a QAM signal is not transmitted on the activated link at each time, and a signal known to both the transmitting and receiving ends is transmitted. The channel model is as follows:
Figure BDA0000919361890000101
wherein the content of the first and second substances,
Figure BDA0000919361890000102
is a matrix of frequency domain equivalent channel coefficients,
Figure BDA0000919361890000103
for a flat fading MIMO matrix, i.e. a complex gaussian distribution whose elements are subject to independence, with a mean of 0 and a variance of 1,
Figure BDA0000919361890000104
is an originating spatial correlation matrix used for measuring the correlation between originating links. Matrix RTThe elements in (1) can be represented as:
Figure BDA0000919361890000105
the element represents the correlation between the mth link and the nth linkProperty dm,nIs the distance between the mth link and the nth link, dminRepresents the minimum distance between links, p represents the correlation coefficient, and (). indicates the conjugate.
The layered data transmission service is provided by adopting a layered grouping mode among the links. One preferred link grouping is based on inter-link correlation, as shown in fig. 3. In fig. 3, all links are divided into N groups, which are set as group 1 and group 2 … … group N, respectively, according to the correlation between the links. Here, it is assumed that the spatial modulation system activates only one link. After grouping, use b1~bnIndicating the activated link, and the inter-group bit indicates in which group the activated link is; the intra-group refers to the bit indicating that the activated link is at a particular location within the group. In this grouping method, links with strong correlation (i.e., the correlation index is greater than a set threshold) are grouped into one group, and links belonging to different groups have low correlation. Meanwhile, the upper bits of the transmission bit group are used to indicate in which packet the active link is located, and the lower bits are used to indicate the active link within the group (i.e., which link within the group is active). It should be noted that the grouping manner can be nested, that is, the grouping can be continued according to the correlation in the group, thereby achieving the purpose of transmitting data in multiple layers.
In this embodiment, SSK modulation of 16 available links can transmit 4 bits of information per communication, and all links are grouped in three layers. Firstly, for the first layer grouping, the first 8 links are divided into a group, the last 8 links are divided into a group, and the highest bit indicates which link in the group is activated; secondly, dividing each link group into two groups according to the correlation, wherein each group comprises 4 links with strong correlation respectively and is used as a second layer group, and indicating by using a second high-order bit; finally, the two bits of the remaining lowest order bits are used to indicate which of the 4 links in the group is activated as a layer three packet. Fig. 4 is a schematic diagram of bit grouping in the present embodiment. In 4 bits of information, b is shown in FIG. 41To indicate the bits of the first layer packet, b2To indicate the bits of the second layer packet, b3And b4Is a bit indicating a layer three packet.
First, consider a case where the receiving end is equipped with four links and the channel correlation coefficient ρ is 0.1. Fig. 5 shows the bit error rates that can be obtained for different packets in this case. Wherein, the legend 'first layer' indicates the first layer packet, i.e. the bit error rate of the most significant bit; 'second layer' means a bit error rate of a second layer packet, i.e., a second highest bit; 'third layer' represents a third layer packet, i.e., the bit error rate of the least significant bit; the 'average' represents the total bit error rate. It can be seen that in this case, the first layer packets have the best error performance, while the third layer packets have the worst performance. The performance of the first layer packet is about 2dB better than the second layer packet and about 4dB better than the third layer packet for the same bit error rate. Therefore, for users with better channel conditions and higher signal-to-noise ratio at the receiving end, all three layers of data can be solved; for users with low signal-to-noise ratio, only the first layer packet data with the best error code performance can be solved.
Next, consider a case where the receiving end is equipped with two links, and the channel correlation system ρ is 0.3. Fig. 6 shows the bit error rates that can be obtained for different packets in this case. Wherein, the legend 'first layer' indicates the first layer packet, i.e. the bit error rate of the most significant bit; 'second layer' means a bit error rate of a second layer packet, i.e., a second highest bit; 'third layer' represents a third layer packet, i.e., the bit error rate of the least significant bit; the 'average' represents the total bit error rate. Similar to the result of fig. 5, under this condition, a significant performance difference can still be obtained between different packets, so that the user can select a suitable data rate according to the own channel status.
Finally, consider the case that the receiving end is equipped with two links, and the channel correlation system ρ is 0.5. Fig. 7 shows a comparison of the bit error rates obtained for different packets in the case of high correlation of the link. Wherein, the legend 'first layer' indicates the first layer packet, i.e. the bit error rate of the most significant bit; 'second layer' means a bit error rate of a second layer packet, i.e., a second highest bit; 'third layer' represents a third layer packet, i.e., the bit error rate of the least significant bit; the 'average' represents the total bit error rate. In this case, the properties between different layersThe energy difference is more obvious. E.g. a bit error rate of 10-3The first layer data performs about 5dB better than the second layer data and about 8dB better than the third layer data.
The simulation results of fig. 5 to fig. 7 show that it is more effective to configure multiple antennas at the receiving end or to provide certain correlation between links by using the manner of transmitting hierarchical data by using correlation between links, so as to provide differentiated services for users with different signal-to-noise ratios while ensuring the basic services of the users.
The above results show that the link grouping method provided by this embodiment can provide different error rate performance between different groups, and therefore, it is beneficial for the system to transmit different data on different groups. One possible way is to transmit the most basic information on bits of a first layer packet, and the bits of each layer packet thereafter carry the extension information on a layer-data basis. For example: the extension information may be additional service data on the basic service, or may be data for improving the definition of time and frequency or the definition of voice. Thus, each layer of decoded data can obtain the improvement of data rate on the basis of the previous layer of data. Another possibility is to transmit the most basic information on the bits of the first layer packet and redundant information (e.g. channel coded check bits or repetition of the first layer packet information) on the bits of each layer packet after it. Therefore, the reliability can be improved on the basis of the previous layer of data when one layer of data is solved, and the robustness of the system is improved. To achieve both data rate and reliability improvements, the two approaches can be used in combination.
In order to facilitate the detection of each layer of data at the receiving end, each layer of data can be partitioned and mutually independent CRC check codes can be added. This may reduce the data rate slightly, but may facilitate layered data detection by the user. Fig. 8 is a schematic diagram illustrating such a data layering manner. In the figure, the first layer data is basic data, and the other layer data is extension or redundancy based on the first layer data, in the example, each layer of data is divided into a data block 1 and a data block 2, and mutually independent CRC check codes are respectively added to the data block 1 and the data block 2.
In the channel of this embodiment, links are grouped according to the correlation between the links. Since the used channel model has a larger correlation between links at close distances, the grouping may be performed directly according to the ranking order of the links in this embodiment. Because most of systems adopt dual-polarized antennas, antenna groups with different polarizations can be considered to be independent, and therefore the first layer of grouping can be determined by using polarization directions among different antennas. Grouping according to the distance between antennas of the same polarization direction is also reliable, considering that there tends to be higher correlation between adjacent antennas. In addition, it is also possible to determine which links have higher correlation according to the channel state information fed back by the user, and perform inter-link grouping according to the information.
It should be noted that, although the simulation provided in this embodiment does not consider the case of transmitting constellation point symbols, such as QAM symbols or PSK symbols, a part of information may be carried on the constellation point symbols in an actual system for transmission. Considering that most of actually used low-complexity detection algorithms need to detect the used link first, and then subsequent constellation point symbol detection is carried out after the link activated by the originating terminal is determined. Therefore, if the link detection is wrong or has a large uncertainty, the detection of the constellation point symbols will be adversely affected. In this case, the constellation point symbol may be transmitted as data of a layer of lower priority or importance. Another way to transmit the constellation point symbols is to transmit a separate data stream using the constellation point symbols, and decide whether to retain the data stream by CRC detection. In some special environments, for example, in the presence of a strong direct path, which is a link with strong correlation, although link detection may be inaccurate, the accuracy of the constellation point symbol can still be ensured, and in this case, the constellation point symbol is used to transmit a single data stream, which can improve throughput. At this time, the data stream transmitted using the constellation point symbol should be some auxiliary data on the basic data, such as some layer data repetition or redundancy, or some new auxiliary data information.
Example two:
the embodiment will provide a multicarrier spatial modulation technique supporting layered transmission for preprocessing at the transmitting end. In some practical systems, due to lack of feedback or non-ideal feedback and other factors, link grouping configuration of a base station may not be guaranteed to meet requirements of all users, and at this time, differences among different groups can be improved by preprocessing different links at the base station side, so that the probability of correct detection is improved.
The pre-processing in this embodiment includes, but is not limited to, power allocation and rotational phase. Two methods of pretreatment are described separately below.
1. And (4) power distribution.
On the premise of ensuring that the average transmitting power is not changed, the average transmitting power of each group in the first layer is adjusted, so that different groups have different average transmitting powers; on the premise of ensuring that the average transmitting power of each group in the first layer is not changed, the average transmitting power of each group in the second layer is adjusted to ensure that different groups in the second layer have different average transmitting powers; and recursion is carried out according to the steps to finally obtain the power distribution result of each group in each layer. To ensure that the detection of the previous layer is not affected by the power adjustment of the next layer, it is necessary to provide that the power adjustment of the previous layer is strictly greater than the power adjustment of the next layer. Fig. 9 shows an example of inter-link power allocation.
Fig. 9 shows a packet configuration for two-layer transmission with 4 links available to the base station. Wherein the first layer contains two links per packet and the second layer contains one link per packet. Assuming that the average transmission power is 1, the average power of the two packets in the first layer is adjusted on the premise of ensuring that the average transmission power is not changed. For example, as shown in FIG. 9, the average power of the first layer packet 1 is adjusted to 1+ p and the average power of the first layer packet 2 is adjusted to 1-p. And on the premise of ensuring that the average power of each group of the first layer is not changed, adjusting the power of each group of the second layer. For example, the average power of each packet of the second layer is respectively adjusted to: 1+ p1,1+p-p1,1-p+p1,1-p-p1. To ensure that detection of first layer packets is not subject to second layer power splittingInfluence of the recipe, p needs to be ensured>p1
2. The phase is rotated.
Besides the power adjustment between different links, the discrimination between different packets can be increased by rotating the phase. One possible criterion for rotating the phase is to randomly select a rotating phase for the links of each packet of the lowest layer, the randomly selected phase intervals of each packet being disjoint, and to select adjacent phase intervals for the links of the respective packets belonging to the same packet in the previous layer. Also, taking the system with 4 links and 2 tiers as an example shown in fig. 9, four phase intervals are selected as the rotational phase intervals since the number of packets in the lowest tier is 4. Considering that the second layer packets 1, 2 belong to the same packet of the first layer (i.e. first layer packet 1) and the second layer packets 3, 4 belong to another packet of the first layer (i.e. first layer packet 2), adjacent rotating phase intervals are selected for the second layer packets 1, 2 and further adjacent rotating intervals are selected for the second layer packets 3, 4. One simple example is: the rotating phase intervals of the four groups of the second layer are respectively as follows:
[0,π/8],[π/8,π/4],[π/2,5π/8],[5π/8,3π/4]。
it should be noted that the two methods can be combined, that is, the power adjustment and the phase rotation are performed simultaneously, so as to further increase the distance between different sub-groups.
When transmitting a reference signal for packet channel estimation, which can be used for demodulation of each packet, the reference signal is subjected to the same preprocessing, and thus the reference signal can be directly used for estimation of the preprocessed equivalent channel coefficients. In addition, for an actual system based on physical resource block scheduling, each time-frequency resource of the same physical resource block uses the same preprocessing mode.
Example three:
the present embodiment will give an explanation on the operation flow of the multi-carrier spatial modulation technique supporting layered transmission in an actual system.
Fig. 10 is a flowchart illustrating an operation of the multi-carrier spatial modulation technique supporting layered transmission according to this embodiment. At the base station side, firstly informing User Equipment (UE) of link number information and link grouping configuration information used in data transmission, layering data to be transmitted according to the selected link number information and the link grouping configuration information, then transmitting a reference signal corresponding to the selected link, and transmitting the data to be transmitted to the UE after carrying out multi-carrier spatial modulation. The link number information may be preset or included in the link grouping configuration information, and therefore, the link number information is information that can be sent optionally. In addition, a mode can be set for the link grouping, and the base station can specify a specific link grouping mode to the UE, so that the UE can know the grouping of the links and the information of the links contained in each group.
At the UE side, firstly reading the link number information and the link grouping configuration information, then estimating the link channel state information through the reference signal of each link or grouping according to the information, finally detecting the data flow and obtaining the estimation of the transmitted data.
The link number information refers to the number of links used for transmitting the spatial modulation signals, and since the base station is often equipped with more antennas, more links can be supported, but according to the channel conditions and the difference of the users served, the appropriate number of links needs to be selected according to the specific situation; the link grouping configuration information refers to the grouping condition of the links after the number of the links is selected. For one link number, only one or two link grouping configurations need to be specified. For example, when the number of links used by the base station is 8, one link is configured such that every four links are divided into one group as a first layer, and every two links are divided into one group as a second layer; or every two links are grouped into a group as the first layer. The specific link packet configuration is also determined by the channel conditions, user configuration. In conjunction with the link number information and the link packet configuration information, the specific packet configuration used by the base station may be determined.
The above process is described in detail below.
When notifying the UE of the link number information and the link packet configuration information, the base station may transmit in a Physical Broadcast Channel (PBCH) or a Physical Downlink Control Channel (PDCCH). When transmitting in PBCH, the following two ways can be selected:
1. a new field is added in PBCH for transmitting link number information and link packet configuration information.
As shown in fig. 11, two fields (as shown in the extra field in fig. 11) are added in the reserved bits of PBCH, namely, a link number information indication field and a link packet configuration information indication field.
In PBCH, the number of antenna ports is 1, 2, or 4, and the user performs detection by blind detection and CRC mask detection, so that it is only necessary to notify that the number of antenna ports is greater than 4. For example, in the case where the base station is equipped with 128 antennas, the number of links that can be used for multicarrier spatial modulation is 2, 4, 8, 16, 32, 64, and 128 (i.e., powers of 2), and when notifying the number of used links, only the case where the number of links is greater than 4 may be notified, and one possible notification method is shown in table 2.
Table 2: possible link number information indication mode when the number of links is 128
Figure BDA0000919361890000151
In table 2, the UE is informed of the number of links using 3 bits, where the last two cases are reserved, which indicates that this approach can support more number of links. In addition, considering that the same link number only needs to support one or two packet configurations to meet the requirement of layered transmission, the two newly added fields only need to occupy 4 bits. Considering that the reserved number of bits in PBCH is 10, 4 bits of overhead is acceptable.
2. The link number information is transmitted through the CRC mask.
The conventional PBCH channel informs the user of the number of antenna ports by blind detection in transmission mode and CRC mask, that is, the CRC check code is added with a mask corresponding to the number of antenna ports. The user link number information can be notified without adding an extra field by adding an available CRC mask.
Fig. 12 shows a preferred way of carrying the link number information using a CRC mask. The transmission modes adopted by the PBCH include a single antenna port mode, a double antenna port antenna diversity mode and a four antenna port antenna diversity mode. In order to ensure the reliability of PBCH transmission information, available CRC masks are divided into three groups, which respectively correspond to a single-antenna port, a double-antenna port and a four-antenna port. Taking fig. 12 as an example, CRC masks 1, 2, and 3 all correspond to a single antenna port, and a user solves one of the masks to determine that the transmission mode used by the PBCH is a single antenna port mode. Each CRC mask in turn represents a type of link number information used by the actual broadcast channel. For example, if the number of configured broadcast channel use links is 16 and PBCH transmission uses the single antenna port mode, CRC mask 3 is selected to process CRC check bits. After the user knows to use the mask 3 through the CRC check, the PBCH transmission mode can be known as the single antenna port mode, and the number of the links used by the broadcast channel is known to be 16. When this method is used, the link packet configuration information still needs to add an extra field in the reserved bit to inform the user.
In addition, the two modes can be used in combination, namely, the number of the ports is informed by using the CRC mask while an extra field is added in the reserved bits of the PBCH, so that the effect of improving the information reliability is achieved.
The link number information and the link grouping configuration information may also be transmitted in a downlink control channel, that is, an additional field is added in the control channel for indicating the link number information and the link grouping configuration information. One possible way to indicate the link number information is shown in table 2, where bit 000 indicates that the link configuration used is the same as in PBCH.
In addition to the above two modes, the link number information and the link packet configuration information may also be transmitted in a Physical Downlink Shared Channel (PDSCH).
The base station layers the data according to one or more of the following criteria:
1. layering according to the data priority, namely allocating a bit layer with the highest reliability to the data with the highest priority; distributing a bit layer with the second highest reliability for the data with the second highest priority; and in analogy, the data with the lowest priority is allocated with the bit layer with the lowest reliability. The priority can be the priority of the application data, that is, the data with the highest priority needs to be decoded more efficiently and more reliably, while the requirement of the data with low priority on the reliability can be relaxed; or the priority of the multimedia data, i.e. the high priority is the basic data, the basic multimedia service can be obtained by decoding the high priority data, and further detecting the low priority data can improve the service quality on the basis of the basic service.
2. Or transmitting basic information bits on the bit layer with the highest reliability, performing channel coding on the basic information bits, transmitting redundant information bits on the bit layer with the second highest reliability, and further transmitting the redundant bits obtained after coding on the bit layer with the lower reliability. Thus, the reliability of the received signal can be improved for each layer of data detected. In addition, the two layering modes can be used jointly to improve the data rate and the reliability at the same time.
When the user performs data detection, the data detection can be performed in the following two ways:
1. and (4) joint detection. Namely, the user performs joint detection on the data of each layer, and obtains an estimated value of the data transmitted by each layer. Then estimating the received signal-to-noise ratio of each layer of data, and selecting the layered data stream above a certain threshold value for further processing (such as channel decoding, source decoding and the like); if the layered data adopts a mode of adding CRC in blocks, CRC check can be carried out on each layer of data, and each layer passing the check is reserved.
2. And (5) detecting layer by layer. That is, the information transmitted by each layer of data is detected layer by layer according to the channel state information of each layer until the received signal-to-noise ratio of a certain layer cannot reach a certain threshold, or until the CRC check of a certain layer fails.
Example four:
in this embodiment, a reference signal configuration method using the scheme provided in this application will be given.
The reference signals may be processed in an insertion manner in a conventional communication system, that is, the reference signals for channel estimation of different links are transmitted using mutually orthogonal resources, that is, on mutually orthogonal frequency domain and time resource, or transmitted on the same time-frequency resource, but different links are distinguished by using mutually orthogonal codes. This method can estimate the channel state information of each link. When data detection is performed, data of each group can be jointly detected, and data of groups with reliability reaching above a certain threshold value can be selected for further processing. The channel state information of each group can also be obtained in a combination mode, and then the data of each layer is detected and obtained in a layer-by-layer detection mode until the signal of a certain layer reaches the threshold value of the signal-to-noise ratio.
In this embodiment, a manner of transmitting reference signals in a packet manner will be given. The basic idea is to transmit the reference signal in packets such that the data of each layer can be directly detected based on the channel state information of the packets, thereby simplifying the design of the receiver. Fig. 13 shows a simple example of a packet transmission reference signal when the number of links at the transmitting end is 8 and the number of layers is 3. In fig. 13, the first layer packet includes two groups, each group including four links. To distinguish the two packets of the first layer, two orthogonal reference signals of length 2 are required, as shown by RS1 and RS 2. When the reference signal of the layer is transmitted, under the premise of ensuring the power constraint, the four links belonging to the same group transmit the same reference signal data, and the four links of the other group transmit the reference signal data orthogonal to the signal. Each packet in the second layer packet includes two links, and only two orthogonal reference signals with the length of 2 need to be transmitted to distinguish different packets. Specifically, in fig. 13, link 1 and link 2 transmit the same reference signal, RS3, while link 5 and link 6 transmit a reference signal orthogonal to the signal, RS4, and the remaining links are inactive. The channel state information of the other two packets can be calculated in combination with the channel state information of the first layer packet. In transmitting the channel state information of the third layer packet, four orthogonal reference signals with length of 4 are used, as shown in RS5 to RS8, i.e. only the channel state information of links 1, 3, 5, 7 need to be estimated, while the rest of the links are obtained in combination with the channel state information of the second layer.
The method for transmitting the reference signal in the packet mode can simplify the operation of the user under the condition of not consuming extra resources, so that the user with poor channel conditions can solve the basic data more quickly.
Fig. 14 is a schematic diagram of time-frequency resource allocation of reference signals for packet transmission. For the example shown in fig. 13, the conventional reference signal transmission method needs 8 orthogonal reference signals, and eight orthogonal time-frequency resources are needed. According to the foregoing description, layer 1 requires two orthogonal reference signals, and requires two orthogonal time-frequency resources; layer 2 requires two orthogonal reference signals and two orthogonal time frequency resources; while layer 3 requires four orthogonal reference signals and four orthogonal time-frequency resources. Therefore, the time frequency resources required by the invention are the same as the traditional mode, but the scheme of the invention can better support layer-by-layer detection and has more advantages for users with poor channel conditions.
Example five:
in this embodiment, a scheme for determining the link grouping configuration and the user grouping configuration according to the channel state information fed back by the user will be given.
Although the multimedia broadcast/multicast service in LTE-a does not support the adjustment of the processing of the transmitting end according to the information fed back by the user, for the scheme proposed in the present application, the number of used links and the link packet configuration are adjusted according to the channel state information fed back by the user, so that the service can be better provided for users with different channel conditions. Meanwhile, the feedback-based scheme can also be applied to serve users in the open-loop mode. Specifically, as shown in fig. 15, according to the channel state information fed back by the user, the base station groups users having the same or similar link number information and link grouping configuration information into a group, and performs a broadcast service on the same time-frequency resource.
The specific grouping flow is shown in fig. 16. The base station side sends a downlink reference signal for measuring the channel state information of the downlink physical channel. The Reference Signal may be a Cell-specific Reference Signal (CRS) or a channel state information Reference Signal (CSI-RS) similar to that in LTE/LTE-a. The reference signal has a different effect than the reference signal described in the second embodiment. And the UE estimates a downlink channel according to the reference signal and feeds back the estimated channel state information to the base station. The base station estimates the correlation among links according to the feedback from the UE, determines the link grouping configuration of the users, divides the users with the same or similar link grouping configuration into a group, and performs broadcast service on the same time-frequency resource for the users in the same group.
In order to measure the correlation between links, the base station may estimate the correlation between downlinks by estimating state information of an uplink channel according to a Sounding Reference Signal (SRS) transmitted from the UE to the base station through the uplink channel. For a Time-Division Duplex (TDD) system, the correlation between downlink channels can be directly obtained by using the reciprocity between uplink and downlink channels. For Frequency-Division Duplex (FDD) systems, the correlation between the downlink channels can also be estimated by uplink channel estimation, since the correlation between the links is influenced and determined by the large-scale fading between the channels.
The user can feed back channel state information through the existing Rank Indicator (RI) and Precoding Matrix Indicator (PMI) of LTE, and the base station estimates the correlation between downlinks according to the feedback of the user. In order to facilitate user feedback, a link grouping configuration pattern codebook known by both the base station and the user can be designed, and the user feeds back the link number information through rank indication and feeds back the required link grouping configuration through the link grouping configuration pattern.
By estimating the correlation of the user link, the base station can dynamically adjust the user grouping, and inform the user of the time-frequency resource position required by the broadcast data, the link number information used for hierarchical transmission and the link grouping number information in the downlink control channel or the downlink shared channel. The user reads the information in the downlink control channel or the downlink shared channel to obtain the broadcast data resource allocation information, the used link number information and the link grouping configuration information. Based on this information, the user reads the broadcast data from the corresponding resource.
The signal processing flow of the multi-carrier spatial modulation system based on packet transmission including user grouping and preprocessing is shown in fig. 17. Wherein user grouping and feedback/uplink transmission based link configuration selection are optional parts. The structure shown in fig. 17 is also applicable to transmission of a control channel in addition to a broadcast channel providing a multimedia broadcast/multicast service. When the structure is applied to a control channel, the basic data contains some control information necessary for the system, and the extended data can be some extended control data used for increasing the transmission data rate of the control channel, or redundancy or copy of the basic data used for increasing the reliability of the control channel; the method and the device can also be used for a receiver working in an open loop mode, the receiver in the mode can not effectively feed back channel state information, and by using the scheme provided by the application, the receiver can spontaneously adjust the rate of receiving data according to the change of the channel condition, thereby providing greater flexibility and reliability.
In response to the above method, the present application provides a transmitter, whose constituent structure is shown in fig. 18, including:
a configuration module for transmitting link grouping configuration information; the link grouping configuration information is information of links contained in each group after the link is divided into at least two groups;
the data layering module is used for layering the data stream to be transmitted according to the grouping of the link;
the spatial modulation module is used for carrying out spatial modulation on the layered data stream;
the multi-carrier modulation module is used for carrying out multi-carrier modulation on the signals after the spatial modulation;
and the sending module is used for sending the signal after the multi-carrier modulation.
Corresponding to the above method, the present application further provides a receiver, whose constituent structure is shown in fig. 19, including:
a configuration information receiving module for receiving link grouping configuration information;
the grouping confirmation module is used for acquiring the grouping of the link and the information of the link contained in each grouping according to the link grouping configuration information;
and the detection module is used for carrying out layered detection on the received data according to the grouping of the link.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims (44)

1. A method for signaling, the method comprising:
the transmitter transmits link grouping configuration information; the link grouping configuration information is information of links contained in each group after the link is divided into at least two groups;
the transmitter carries out layering on data streams to be transmitted according to the grouping of the link;
the transmitter performs spatial modulation on the layered data stream;
the transmitter carries out multi-carrier modulation on the signals after the space modulation;
the transmitter transmits the signal after multi-carrier modulation;
wherein the content of the first and second substances,
the transmitter layering data streams to be transmitted according to the grouping of the link comprises:
the first data is transmitted with packets in the first layer,
transmitting second data with a packet in an nth layer, n being a natural number greater than 1;
the second data includes at least one of: the data processing method comprises the following steps of expanding data based on first data, redundant information of the (n-1) th layer of data, and combination of the expanding data and the redundant information.
2. The method of claim 1, wherein: the dividing the link into at least two packets comprises: dividing all available links into at least two groups, and taking the obtained groups as each group in the first layer; dividing each group in the first layer into at least two groups, and taking the obtained group as each group in the second layer; and so on until each packet contains only one link or the set link packet requirements are met.
3. The method of claim 1, wherein:
the criteria for grouping the links are: and grouping the links with the relevance indexes larger than a set threshold value.
4. The method of claim 3, wherein:
the method further comprises the following steps: the transmitter estimates the correlation index between links according to the information from the receiver and dynamically adjusts the number of links and the grouping of the links according to the correlation index; the information from the receiver comprises channel state information fed back by the receiver and/or a sounding reference signal sent to the transmitter by the receiver through an uplink channel.
5. The method of claim 4, wherein:
the method further comprises the following steps: and dividing users with the same link grouping configuration information into a group, and performing broadcast service on the same time-frequency resource for the users in the same group.
6. The method of any one of claims 1 to 5, further comprising:
and after preprocessing the signal after spatial modulation, performing multi-carrier modulation and transmitting.
7. The method of claim 6, wherein:
the pretreatment comprises the following steps: power adjustment is performed on the link and/or phase adjustment is performed on the link.
8. The method of claim 7, wherein:
the power adjusting the link comprises: under the condition of keeping the transmission power unchanged, adjusting the average transmission power of each group in the first layer to ensure that each group has different average transmission power; under the condition of keeping the average transmitting power of each group in the first layer unchanged, adjusting the average transmitting power of each group in the second layer to ensure that each group in the second layer has different average transmitting power; and repeating the steps until the average transmitting power of each packet of the lowest layer is adjusted.
9. The method of claim 8, wherein:
the criterion for adjusting the average transmit power of each layer packet is: the power adjustment amount of the latter layer is not larger than that of the former layer.
10. The method according to any one of claims 7 to 9, wherein:
the phase adjusting the link comprises: the rotating phases are randomly selected for the links of the respective packets of the lowest layer, the intervals of the rotating phases of the respective links belonging to different packets are disjoint, and adjacent rotating phase intervals are selected for the links of the respective packets belonging to the same packet in the previous layer.
11. The method of claim 2, wherein:
the lowest layer data is transmitted using constellation point symbols in spatial modulation, or other auxiliary or redundant information is transmitted.
12. The method of claim 1, wherein:
the method further comprises the following steps: the transmitter transmits the reference signal according to the packet of the link.
13. The method of claim 12, wherein:
the transmitter transmitting the reference signal according to the packet of the link includes: the transmitter transmits the same reference signal sequence using the same time-frequency resources for the links belonging to the same group for estimation of the equivalent channel coefficients of the corresponding group.
14. The method according to claim 12 or 13, characterized in that:
if the spatial modulated signal is preprocessed, then multi-carrier modulated and transmitted, before transmitting the reference signal, the method further includes: the reference signal is subjected to the preprocessing.
15. The method of claim 1, wherein:
the method further comprises the following steps: and partitioning the layered data of each layer, and adding an independent Cyclic Redundancy Check (CRC) code to the data of each layer in each data block.
16. The method of claim 1, wherein:
the transmitter transmits the link number information and the link grouping configuration information in at least one of a physical broadcast channel, a downlink physical control channel and a physical downlink shared channel.
17. The method of claim 16, wherein:
the transmitter transmits a physical broadcast channel, a downlink physical control channel or a physical downlink shared channel added with an additional field, wherein the additional field is used for indicating the link number information and the link grouping configuration information.
18. The method of claim 16, wherein:
the transmitter transmits the link number information by using CRC check masks in the physical broadcast channels, the transmission mode of each physical broadcast channel corresponds to at least two CRC check masks, and each CRC check mask corresponds to one link number information respectively; the transmission mode of the physical broadcast channel comprises a single antenna port transmission mode, a double antenna port transmission diversity mode and a four antenna port transmission diversity mode;
the transmitter transmits a physical broadcast channel, a downlink physical control channel or a physical downlink shared channel to which an additional field for indicating link grouping configuration information is added.
19. A transmitter, comprising:
a configuration module for transmitting link grouping configuration information; the link grouping configuration information is information of links contained in each group after the link is divided into at least two groups;
the data layering module is used for layering the data stream to be transmitted according to the grouping of the link;
the spatial modulation module is used for carrying out spatial modulation on the layered data stream;
the multi-carrier modulation module is used for carrying out multi-carrier modulation on the signals after the spatial modulation;
a sending module, configured to send the multicarrier-modulated signal;
wherein the data layering module is configured to:
the first data is transmitted with packets in the first layer,
transmitting second data with a packet in an nth layer, n being a natural number greater than 1;
the second data includes at least one of: the data processing method comprises the following steps of expanding data based on first data, redundant information of the (n-1) th layer of data, and combination of the expanding data and the redundant information.
20. The transmitter of claim 19, wherein:
the dividing the link into at least two packets comprises: dividing all available links into at least two groups, and taking the obtained groups as each group in the first layer; dividing each group in the first layer into at least two groups, and taking the obtained group as each group in the second layer; and so on until each packet contains only one link or the set link packet requirements are met.
21. The transmitter of claim 19, wherein:
the criteria for grouping the links are: and grouping the links with the relevance indexes larger than a set threshold value.
22. The transmitter of claim 21, wherein:
the transmitter is further configured to: estimating a correlation index between links according to information from a receiver, and dynamically adjusting the number of links and the grouping of the links according to the correlation index; the information from the receiver comprises channel state information fed back by the receiver and/or a sounding reference signal sent to the transmitter by the receiver through an uplink channel.
23. The transmitter of claim 22, wherein:
the transmitter is further configured to: and dividing users with the same link grouping configuration information into a group, and performing broadcast service on the same time-frequency resource for the users in the same group.
24. The transmitter according to any of claims 19 to 23, characterized in that the transmitter is further configured to:
and after preprocessing the signal after spatial modulation, performing multi-carrier modulation and transmitting.
25. The transmitter of claim 24, wherein:
the pretreatment comprises the following steps: power adjustment is performed on the link and/or phase adjustment is performed on the link.
26. The transmitter of claim 25, wherein:
the power adjusting the link comprises: under the condition of keeping the transmission power unchanged, adjusting the average transmission power of each group in the first layer to ensure that each group has different average transmission power; under the condition of keeping the average transmitting power of each group in the first layer unchanged, adjusting the average transmitting power of each group in the second layer to ensure that each group in the second layer has different average transmitting power; and repeating the steps until the average transmitting power of each packet of the lowest layer is adjusted.
27. The transmitter of claim 26, wherein:
the criterion for adjusting the average transmit power of each layer packet is: the power adjustment amount of the latter layer is not larger than that of the former layer.
28. The transmitter according to any one of claims 25 to 27, wherein:
the phase adjusting the link comprises: the rotating phases are randomly selected for the links of the respective packets of the lowest layer, the intervals of the rotating phases of the respective links belonging to different packets are disjoint, and adjacent rotating phase intervals are selected for the links of the respective packets belonging to the same packet in the previous layer.
29. The transmitter of claim 20, wherein:
the lowest layer data is transmitted using constellation point symbols in spatial modulation, or other auxiliary or redundant information is transmitted.
30. The transmitter of claim 19, wherein:
the transmitter is further configured to: the reference signal is transmitted according to a packet of the link.
31. The transmitter of claim 30, wherein:
the transmitter transmitting the reference signal according to the packet of the link includes: the transmitter transmits the same reference signal sequence using the same time-frequency resources for the links belonging to the same group for estimation of the equivalent channel coefficients of the corresponding group.
32. The transmitter according to claim 30 or 31, characterized in that:
if the spatially modulated signal is pre-processed, then multi-carrier modulated and transmitted, then before transmitting the reference signal, the transmitter is further configured to: the reference signal is subjected to the preprocessing.
33. The transmitter of claim 19, wherein:
the transmitter is further configured to: and partitioning the layered data of each layer, and adding an independent Cyclic Redundancy Check (CRC) code to the data of each layer in each data block.
34. The transmitter of claim 19, wherein:
the transmitter transmits the link number information and the link grouping configuration information in at least one of a physical broadcast channel, a downlink physical control channel and a physical downlink shared channel.
35. The transmitter of claim 34, wherein:
the transmitter transmits a physical broadcast channel, a downlink physical control channel or a physical downlink shared channel added with an additional field, wherein the additional field is used for indicating the link number information and the link grouping configuration information.
36. The transmitter of claim 34, wherein:
the transmitter transmits the link number information by using CRC check masks in the physical broadcast channels, the transmission mode of each physical broadcast channel corresponds to at least two CRC check masks, and each CRC check mask corresponds to one link number information respectively; the transmission mode of the physical broadcast channel comprises a single antenna port transmission mode, a double antenna port transmission diversity mode and a four antenna port transmission diversity mode;
the transmitter transmits a physical broadcast channel, a downlink physical control channel or a physical downlink shared channel to which an additional field for indicating link grouping configuration information is added.
37. A method for receiving a signal, the method comprising:
the receiver receives link grouping configuration information;
the receiver acquires the grouping of the link and the information of the link contained in each grouping according to the link grouping configuration information;
the receiver carries out layered detection on the received data according to the grouping of the link;
wherein the content of the first and second substances,
the received data is transmitted according to the signalling method of any of claims 1 to 18.
38. The method of claim 37, wherein:
the receiver carries out layered detection on the received data according to the grouping of the link, and the layered detection comprises the following steps:
the receiver detects the sending data of all layers according to the channel state information of each link, and determines the reserved layer number according to a set criterion; wherein the set criteria include: comparing the signal-to-noise ratio estimation of each layer of detected data with a preset signal-to-noise ratio threshold, if the signal-to-noise ratio estimation is higher than the signal-to-noise ratio threshold, retaining the data of the corresponding layer and carrying out subsequent processing, otherwise, not carrying out the subsequent processing; or, the set criteria include: the transmitter decides for each receiver whether to retain the data of the corresponding layer according to whether CRC check passed or not added by the transmitter for each layer data individually.
39. The method of claim 37 or 38, wherein:
the method further comprises the following steps: and the receiver detects data of each layer by layer according to the channel state information of each group, compares the signal-to-noise ratio estimation of the detected data of each layer with a preset signal-to-noise ratio threshold value, continues the detection of the data of the next layer if the signal-to-noise ratio estimation is higher than the signal-to-noise ratio threshold value, and stops the detection if the signal-to-noise ratio estimation is not higher than the signal-to-noise ratio threshold value.
40. The method of claim 37, wherein:
the method further comprises the following steps: the receiver receives the reference signal from the packet of the link and performs channel estimation.
41. A receiver, comprising:
a configuration information receiving module for receiving link grouping configuration information;
the grouping confirmation module is used for acquiring the grouping of the link and the information of the link contained in each grouping according to the link grouping configuration information;
the detection module is used for carrying out layered detection on the received data according to the grouping of the link;
wherein the content of the first and second substances,
the received data is transmitted according to the signalling method of any of claims 1 to 18.
42. The receiver of claim 41, wherein: the detection module is used for
Detecting the sending data of all layers according to the channel state information of each link, and determining the reserved layer number according to a set criterion; wherein the set criteria include: comparing the signal-to-noise ratio estimation of each layer of detected data with a preset signal-to-noise ratio threshold, if the signal-to-noise ratio estimation is higher than the signal-to-noise ratio threshold, retaining the data of the corresponding layer and carrying out subsequent processing, otherwise, not carrying out the subsequent processing; or, the set criteria include: the transmitter decides for each receiver whether to retain the data of the corresponding layer according to whether CRC check passed or not added by the transmitter for each layer data individually.
43. A receiver as claimed in claim 41 or 42, characterised in that: the receiver is also used for detecting data of each layer by layer according to the channel state information of each group, comparing the signal-to-noise ratio estimation of the detected data of each layer with a preset signal-to-noise ratio threshold value, if the signal-to-noise ratio estimation is higher than the signal-to-noise ratio threshold value, continuing the detection of the data of the next layer, and if not, stopping the detection.
44. The receiver of claim 41, wherein: the receiver is used for receiving the reference signal according to the grouping of the link and carrying out channel estimation.
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