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OFDM sub-carrier allocation method based on generic algorithm

A genetic algorithm and orthogonal frequency division technology, applied in the field of wireless transmission, can solve the problems of poor connectivity and not fully exerting the diversity effect of the OFDM system, and achieve the effect of improving the data transmission rate, improving the speed of genetic evolution and improving the system performance.

Inactive Publication Date: 2008-03-19
SHANGHAI JIAO TONG UNIV
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  • Summary
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Problems solved by technology

Although this greedy algorithm can obtain better performance relatively simply and quickly, it only obtains a local optimal solution rather than a global optimal solution, and does not fully utilize the diversity effect of the OFDM system.
[0005] Genetic algorithms are particularly suitable for numerically solving non-deterministic global optimization problems with multiple parameters, multiple variables, and multiple regions but poor connectivity

Method used

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  • OFDM sub-carrier allocation method based on generic algorithm
  • OFDM sub-carrier allocation method based on generic algorithm
  • OFDM sub-carrier allocation method based on generic algorithm

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Experimental program
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Embodiment

[0038] This embodiment is based on the traditional Rayleigh scattering channel model, and the channel is modeled as including six independently distributed multipath frequency-selective Rayleigh channels, and the amplitude decays according to an exponential. The maximum delay spread is 5μs, the maximum Doppler frequency shift is 30Hz, the total available power of the system is assumed to be 1W, the total available bandwidth is 1MHz, the total number of subcarriers is 64, and the average channel SNR is 38dB. For the different number of users in the system, 20 different channel implementations are simulated, and each channel implementation is sampled 50 times. For different users, a rate ratio limit condition is randomly set in advance.

[0039] The parameters of the genetic algorithm are shown in Table 1.

[0040] parameters

[0041] For the above parameter settings, the experiment simulates the system capacity and proportionality conditions of the multi-user OFDM sy...

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Abstract

The invention provides an orthogonal frequency division multiplexing (OFDM) system subcarrier allocation method based on SGA in wireless transmission technology field. Firstly, the invention obtains channel status information of each user on different subcarriers, according to channel estimation; and then, transfers SGA for optimum subcarrier allocation; wherein the SGA adopts integer coding and cyclic shift scissor to improve search capability; after fitness function computation of species group with generic variation each time, continues to judge whether the algorithm should stop, according to the termination condition and obtains the subcarrier allocation proposal. Compared with prior art, the invention improves system performance greatly and the advanced SGA in the invention has faster velocity of convergence, compared with the traditional SGA.

Description

technical field [0001] The invention relates to a method in the technical field of wireless transmission, in particular to a subcarrier allocation method for an OFDM system based on a genetic algorithm. Background technique [0002] The basic principle of OFDM technology is similar to that of traditional FDM technology. However, in traditional FDM systems, the entire frequency band is divided into several non-overlapping sub-bands. Both the transmitting end and the receiving end need to use high-performance filters to filter the signal Domain extraction, this method can not improve the spectrum utilization of the system; in the OFDM system, the entire frequency band is divided into many subcarriers, and the subcarriers overlap with each other, and keep orthogonal to each other, which makes the spectrum utilization rate approximately doubled. In addition, since the different subcarriers in the OFDM system are orthogonal to each other and have strong anti-multipath ability, i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L25/03H04J11/00
Inventor 杜学松罗汉文佘锋
Owner SHANGHAI JIAO TONG UNIV
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