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Multi-user random access system based on rateless codes and coding and decoding method thereof

A random access, no rate code technology, applied in transmission systems, digital transmission systems, wireless communications, etc., can solve the problems of unreliable transmission and transmission waste.

Active Publication Date: 2010-04-14
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the estimated channel parameter is greater than the actual channel parameter, although reliable transmission can be achieved, it causes a waste of transmission, because at this time a higher bit rate channel error correction coding can be used; when the estimated channel parameter is less than the actual channel parameter When , reliable transmission cannot be achieved

Method used

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  • Multi-user random access system based on rateless codes and coding and decoding method thereof
  • Multi-user random access system based on rateless codes and coding and decoding method thereof
  • Multi-user random access system based on rateless codes and coding and decoding method thereof

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Experimental program
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Effect test

Embodiment 1

[0093] Embodiment 1: When encoding adopts LT Code, encode as follows:

[0094] Perform LT encoding on m=1024 message data packets to generate Tanner diagram of LT Code, and obtain encoding packets of LT Code continuously generated. use v k (s) represents the coding package of LT Code, wherein s is the numbering (s=1, 2, ...) of the coding package, and the subscript k is the numbering (k=1, 2, ..., K) of the user, The encoding method is: to generate LT Code encoding package v k (s), first according to the degree distribution Ω(x) (the parameters of the distribution are shown in Table 1, where Ω i Indicates the proportion of the degree i), use a random number generator to generate the degree deg for it k (s); then use a random number generator to generate a 1024-dimensional binary domain vector (i=1,2,...,1024), element The value of "0" or "1", where the number of elements "1" is deg k (s). element "1" indicates that the corresponding number is i message data packet d...

Embodiment 2

[0100] Embodiment 2: when encoding adopts Raptor Code (it is made up of the high code rate LDPC Code of outer code part and the LT Code concatenation of inner code part), encode as follows:

[0101] The first step of encoding, according to the Linear-Time PEG Encoding algorithm (see "Regular and IrregularProgressive Edge-Growth Tanner Graphs", IEEE Transactions On Information Theory, Vol.51, No.1, January 2005), for m=1024 message packets Perform LDPC encoding to generate a Tanner graph of LDPC Code, and then obtain n=1072 encoding packets of LDPC Code. use t k (l) represents the encoding package of LDPC Code, wherein l is the numbering (l=1,2,...,1072) of the encoding package, and the subscript k is the numbering (k=1,2,...,K) of the user ).

[0102] The Tanner image of the LDPC Code in the outer part of the Raptor Code is as follows image 3 As shown, there are two types of nodes in the figure, and the circles represent variable nodes, with a total of n=1072, denoted as V...

Embodiment 3

[0113] Embodiment 3: When the mapping mode is BPSK, v k Each bit in (s) is mapped to w kA symbol in (s), the mapping method is: "0→+1, 1→-1", and the coded packet w after mapping is obtained k (s).

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Abstract

The invention discloses a multi-user random access system based on rateless codes and a coding and decoding method thereof, which can adaptively adjust the respective transmission code rate by using the adaptive link adaptation characteristic of the rateless codes and the random characteristic when the rateless codes are coded under the conditions that each user transmitter needs not to know channel state information and no feedback retransmission mechanism is needed in the transmission process, and can effectively use the conflict overlapped information of multiple users to simultaneously transmit the information of the multiple users effectively and reliably and detect and separate the information of the multiple users correctly.

Description

technical field [0001] The invention relates to the field of wireless communication, in particular to a multi-user random access system based on a rateless code and a coding and decoding method thereof. Background technique [0002] In modern wireless mobile communication systems, good multi-user transmission methods must be adopted to ensure that multiple users can transmit information effectively and reliably at the same time. Although the traditional ALOHA technology can realize the transmission under the condition of multi-user single channel, it cannot use the conflicting or overlapping information of multiple users, so the efficiency is not high. The traditional CDMA (Code-Division Multiple-Access) transmission method uses different spreading sequences to distinguish information of different users, so as to complete the access transmission of multi-user information. The IDMA (Interleave-Division Multiple-Access) transmission method proposed by Li Ping (see "Interleave...

Claims

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Application Information

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IPC IPC(8): H04L1/00H04W28/04H04W74/08
Inventor 陈少磊张朝阳吴可镝陈晓明林泽
Owner ZHEJIANG UNIV
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