Double Iteration In A Single Path Fading Channel Interference Suppression Technology Research

Spread spectrum communication technology has the advantage of anti-multipleaccess interference, anti-multipath interference, and code division multiple access. It isthe key communication technology for the third generation mobile communications,satellite communications, wireless LAN and military communications. Because ofconstraints of system complexity and the spectrum resource, spread spectrum gaincannot be increased indefinitely. In the case of strong interference, we have to adopt thenecessary interference suppression technology to improve the performance of spreadspectrum system interference suppression.The existing spread spectrum communication broadband co-channel interferencesuppression technology has the following three deficiencies:(1) The existing algorithm is more for narrowband frequency interferencesuppression. when the interference signal bandwidth and spread spectrumsignal bandwidth can be compared, the interference suppression is poorperformance;(2) Because of the high complexity of the algorithm and time delay of signalprocessing, it is not conducive to the actual implementation;(3) Not effectively using interference signal priori information, it is just regardedas random signal processing only.Therefore, based on the software radio platform, this article studied and hasrealized the double iteration interference suppression technology. While it effectivelysuppresses broadband co-channel interference in spread spectrum communications, thealgorithm can reduce algorithm complexity. The contents of article include thefollowing three aspects:First, in view of broadband frequency interference in spread spectrumcommunication, the article studied a double iteration interference suppression algorithmin one kind of fading channel, and has deduced the algorithms formula of numericalthreshold of SIR. This method through comparing with the actual detective SIR and thevalue critical point chooses different iteration examination order, to promoteinterference suppression performance. The simulation result show that, for differentiteration order, the spreading factor is4, the SIR is5dB, the signal-to-noise ratiois1dB, the error rate reduces28.12%; when the signal-to-noise ratio is7dB, and theerror rate reduces50.67%.Second, the article has realized the double iterative interference suppressiontechnology in software radio platform. Based on the iterative algorithm simulation andsystem design, article designed technical proposal, such as SIR detection and doubleiteration interference suppression, while debugging modem, spread spectrum, filtering,channel estimation on software defined radio platform. Third, article tests double-iteration algorithm for performance, error rate, videotransmission, resource consumption, and so on. The test result indicated that, for thebroadband numeral frequency interference, the double iteration interference suppressiontechnology has promoted68.20%compared to the general interference suppressiontechnical performance.This article studied and has realized the double iteration interference suppressiontechnology. The research of this article enriches the iterative interference suppressionalgorithm and provides a feasible method for co-channel interference suppressiontechnology in spread spectrum communication system.