Method for constructing time-frequency hop sequences in cognitive radio TFH-CDMA system

A technology of TFH-CDMA and cognitive radio, which is applied in the field of time-frequency hopping sequence construction and time-frequency hopping code division multiple access communication system, which can solve the problem of small interval of anti-multiple access interference, small sequence non-collision interval, and sequence Issues such as a small number, to achieve the effect of improving spectrum utilization, anti-multiple access interference, and increasing the number

Inactive Publication Date: 2010-02-10
XIDIAN UNIV
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AI Technical Summary

Problems solved by technology

[0006] 1. The number of sequences in the sequence cluster is too small, which directly limits the number of users in the TFH-CDMA communication

Method used

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  • Method for constructing time-frequency hop sequences in cognitive radio TFH-CDMA system
  • Method for constructing time-frequency hop sequences in cognitive radio TFH-CDMA system
  • Method for constructing time-frequency hop sequences in cognitive radio TFH-CDMA system

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Experimental program
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Embodiment Construction

[0029] refer to figure 2 , the present invention constructs the cognition-based time-frequency hopping sequence clusters as follows:

[0030] Step 1: Construct a frequency hopping sequence cluster S from the current number n of frequency points in the system.

[0031] Let the current frequency points of the system be n=pq, construct a frequency hopping sequence cluster whose length is L=tn+ap, wherein p and q are positive integers, t is an integer greater than 1, and a is an integer between 0 and q, t and a are used to control the length of L,

[0032] 1.1) Construct the first frequency hopping sequence s 1 (l)

[0033] Copy the current n frequency points t times and connect them sequentially, and then add n previous ap frequency points at the end to obtain the first frequency hopping sequence s 1 (l), 0≤l

[0034] 1.2) Construct the remaining q-1 frequency hopping sequences

[0035] Will s 1 (l) Circularly shift right by p bits to get the second frequency hopping s...

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Abstract

The invention provides a method for constructing time-frequency hop sequence clusters in a cognitive radio TFH-CDMA system. The method comprises the following constructing processes: firstly, constructing q optimal hop frequency sequence clusters with the length of L according to the current available frequency point n of the system; then, constructing L direct expansion sequences with the lengthof L, forming one time-frequency hop sequence by any one pair of arbitrary hop frequency sequences and direct expansion sequences and constructing time-frequency hop sequence clusters with the numberof Lq; and constructing corresponding hop frequency sequences when increasing or reducing the number of the available frequency points of the system, and then reconstructing direct expansion sequences with the length equivalent to that of the hop frequency sequences, thereby generating novel time-frequency hop sequence clusters. The time-frequency hop sequence clusters constructed by the invention have the advantages of much number of the sequences, large impact-free interval and high utilization rate of frequency spectra and can be directly applied to a TFH-CDMA communication system based oncognition.

Description

technical field [0001] The invention belongs to the technical field of digital communication, relates to a time-frequency hopping sequence structure, and can be applied to a time-frequency hopping code division multiple access communication system based on cognitive radio. Background technique [0002] Using spread spectrum technology in the CDMA communication system can greatly improve the transmission rate and anti-interference ability of the system. At present, the CDMA system can be divided into: direct sequence spread spectrum CDMA, frequency hopping CDMA and time hopping CDMA according to different ways of spreading. However, using direct sequence spread spectrum technology or frequency hopping technology alone can no longer meet the needs of the system's capacity and transmission rate. The proposal of the time-frequency hopping CDMA system effectively solves this problem, and the system can greatly improve the information transmission rate and system capacity. At th...

Claims

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Application Information

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IPC IPC(8): H04B1/713H04B1/707H04J13/04
Inventor 马文平杨元原孙韶辉
Owner XIDIAN UNIV
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