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Mixed carrier CDMA (Code Division Multiple Access) transmission system

A technology of transmission system and mixed carrier, which is applied in the field of CDMA transmission system, can solve the problem of MC-CDMA system peak-to-average height, etc., and achieve the effects of improving system bit error performance, reducing peak-to-average ratio, and uniform signal energy distribution

Active Publication Date: 2011-06-01
HARBIN INST OF TECH
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Problems solved by technology

[0004] The present invention aims to solve the problem of high peak-to-average ratio in the existing MC-CDMA system, and to improve the system bit error performance under selective fading channels, thereby providing a mixed-carrier CDMA transmission system

Method used

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  • Mixed carrier CDMA (Code Division Multiple Access) transmission system
  • Mixed carrier CDMA (Code Division Multiple Access) transmission system
  • Mixed carrier CDMA (Code Division Multiple Access) transmission system

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specific Embodiment approach 1

[0040] Specific implementation mode 1. Combination Figure 1 to Figure 4 Describe this specific implementation mode, a mixed-carrier CDMA transmission system,

[0041] Assuming that the system has K users, a sequence of length N is used as an address code to distinguish the K users, and the sequence adopted by user i is: The i is an integer greater than or equal to 1 and less than or equal to K; K is a positive integer;

[0042] The signal transmission process of the mixed carrier CDMA transmission system in the downlink transmission process is realized by the following steps:

[0043] Step A1. For user i, use its corresponding sequence For the sequence of input data in the fractional Fourier transform domain of order α Perform sequence expansion to obtain the extended sequence of user i; use data For example, after sequence expansion, it becomes

[0044] Step A2, adding up the extended sequences of all users to obtain an added sequence with a length of N;

[0045]...

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Abstract

The invention discloses a mixed carrier CDMA (Code Division Multiple Access) transmission system, relating to the field of wireless communication, solving the problem of higher peak-to-average ratio of the traditional multi-carrier system and improving the system error-code performance under a selective fading channel. In the invention, on a sending end, sequence spreading is carried out on data of a certain order of fractional Fourier transform domain by adopting a CDMA technology, and the spread data is transformed to a time domain for transmission; and on a receiving end, according to the reversibility of weighted fractional Fourier transform, the data is transformed to the fractional Fourier transform domain again for sequence de-spreading so as to obtain output data. The mixed carrier CDMA transmission system is suitable for mixed carrier signal transmission.

Description

technical field [0001] The invention relates to the field of wireless communication, in particular to a CDMA transmission system. Background technique [0002] In the existing communication system, there are mainly two modes of single carrier and multi-carrier. Single-carrier technology appeared earlier and is relatively mature in technology. Single-carrier technology is not sensitive to carrier synchronization and timing deviation. The peak-to-average ratio of modulated and mapped signals is low. The requirements for equipment power amplifiers are low. The implementation method is simple and cost-effective. lower. The multi-carrier technology divides the high-speed data stream into several low-speed sub-data streams through serial / parallel conversion, and then modulates these low-speed data streams to the corresponding sub-carriers to form multiple low-speed data parallel transmission systems. The multi-carrier technology symbol has a longer duration, which improves the s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L1/00
Inventor 沙学军邱昕梅林王焜房宵杰
Owner HARBIN INST OF TECH
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