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Signal multiple access method and device in mobile communication

A mobile communication and signal technology, applied in the field of communication, can solve the problems of lack of sparsity, negative feedback, affecting detection performance, etc.

Active Publication Date: 2020-07-10
BEIJING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method still has high computational complexity for advanced systems, and new algorithms and structures need to be designed to reduce computational costs
[0005] In the traditional SCMA system model, each user data stream is regarded as a layer, and each layer corresponds to a SCMA codebook, which leads to a small number of data streams, the dimension of the parity check matrix is ​​very small, and it does not have a true sense of sparseness. In addition, a check matrix with a small dimension is prone to short loops, which will bring negative feedback during iterative detection and affect detection performance.

Method used

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  • Signal multiple access method and device in mobile communication
  • Signal multiple access method and device in mobile communication
  • Signal multiple access method and device in mobile communication

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0121] Embodiment 1: The parity check matrix is ​​a regular small-dimensional matrix

[0122]The scheme adopts the traditional SCMA method, and the simulation adopts figure 2 As shown in the factor diagram, there are J=6 users at the sending end, assuming that there is a near-far effect, these 6 users are divided into two groups, each group has three users, the number of subcarriers is K=4, and the overload rate is 150%. The corresponding rule The parity check matrix is ​​as in formula (8), with a row degree of 3 and a column degree of 2.

[0123]

[0124] The codebook used in the simulation is a 4-point codebook constructed according to the traditional SCMA codebook design. The two non-zero parts of each layer data stream are as follows: Figure 9 shown.

Embodiment 2

[0125] Embodiment 2: check matrix is ​​a regular low-density matrix

[0126] Aiming at the problem that the dimension of the traditional SCMA parity check matrix is ​​small, the present invention expands the dimension of the parity check matrix, the number of users is 6 for the simulation, the length of each user's coded information is 96, the code rate R=1 / 2, and QPSK modulation is adopted , then the number of symbols corresponding to each user is 96, using Representing the 96 symbol vectors of the jth user, there are 576 symbols in total before spreading, and these symbols are spread and superimposed on 384 carriers. The parity check matrix corresponding to the above process corresponds to a row degree of 3 and a column degree of 2.

Embodiment 3

[0127] Embodiment 3: The parity check matrix is ​​an irregular low-density matrix

[0128] When the near-far effect exists, the present invention considers constructing an irregular parity check matrix to realize unequal protection for remote users, thereby improving the overall performance of the system. When there is a near-far effect, the present invention still expands the dimension of the parity check matrix. The number of users used in the simulation is 6, the coded information length of each user is 96, the code rate R=1 / 2, and QPSK modulation is adopted, and each user corresponds to The number of symbols is 96, use Representing the 96 symbol vectors of the jth user, there are 576 symbols in total before spreading, and then these symbols are spread and superimposed on 384 carriers. Corresponding irregular check matrix, row degree ρ 4 =0.5, ρ 5 =0.5, the column degree is λ 2 =0.5,λ 4 =0.5, ρ i Indicates the proportion of row degree i, λ i Indicates the proportion...

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Abstract

The invention provides a multiple address access method and device for signals in mobile communication. The method comprises the following steps: A1, in a mobile communication system, obtaining a low-density sparse parity-check matrix based on J users, a business data length m and the number of subcarriers K; A2, based on the low-density sparse parity-check matrix, carrying out LDSM extension on m channel coding symbols of each user, so as to obtain m spread spectrum vectors corresponding to each user; and A3, based on the J users, superposing the m spread spectrum vectors for each user on mK carrier resources to obtain J user signals, and sending the J user signals to a receiving end. The method and device provided by the invention has the advantages that the problem that short cycles exist in the traditional SCMA parity-check matrix when the parity-check matrix lacks sparseness due to small dimensions is solved, and an LDSM parity-check matrix with an irregular distribution is designed for the near-far effect, so that the problem of equality is solved, unequal protection for edge users is achieved, and the detection performance and the network transmission quality are improved.

Description

technical field [0001] The present invention relates to the technical field of communication, and more specifically, to a method and device for multiple access of signals in mobile communication. Background technique [0002] At present, the future 5G system puts forward high requirements on user experience rate, system capacity, number of connections and delay indicators, which poses a serious challenge to the existing orthogonal multiple access technology solutions represented by OFDMA. Compared with traditional orthogonal multiple access, the non-orthogonal multiple access technology characterized by overlay transmission can effectively meet the performance index requirements of typical 5G scenarios. Spectrum efficiency, connection density, and delay are key performance indicators of 5G. Using non-orthogonal multiple access, through the superimposed transmission of multi-user information, more user connections can be supported on the same time-frequency resource, which ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/34
CPCH04B7/0456H04L1/0009H04L1/0041H04L1/0045H04L27/34
Inventor 吴湛击蒋成鑫
Owner BEIJING UNIV OF POSTS & TELECOMM
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