The Research On Signaling Transmission Technology Based On Transform Domain Communication

Transform Domain Communication System(TDCS)is a wireless transmission technology based on cognitive radio.It can adaptively use the unused spectrum in the spectrum range by spectrum analysis.It is also applicable in the case of interference.It greatly improves the utilization of spectrum resources in the case of limited spectrum resources.Based on the transform domain communication system and the advantages of orthogonal frequency division multiplexing(OFDM)system,this paper designs the OFDM-TDCS signaling transmission system,designs the whole system in detail,studies the synchronization technology,channel estimation algorithm,interference suppression algorithm and signaling protocol of the transform domain communication system,and carries out the system performance without interference and interference.The simulation analysis is carried out,and the implementation and performance test are carried out using the general software radio peripheral platform.This paper is divided into the following parts:Firstly,the principle of OFDM-TDCS is explained,the frame format and the parameter configuration of signal link are designed,the transceiver model is given,and the basis function is designed.The synchronization frame is designed based on the training sequence,and the time synchronization scheme and frequency offset estimation scheme are given.Secondly,the interference suppression algorithm and channel estimation denoising algorithm of OFDM-TDCS are studied.In view of the poor performance of LS channel estimation algorithm in slow fading channel,the denoising process based on continuous mean denoising is added on the basis of transform domain low-pass filtering,time average denoising and time window denoising,and the different iterations and thresholds of the algorithm are improved.The simulation results show that the system performance can be effectively improved by choosing appropriate iteration times and thresholds.At the same time,the error code performance of the system in the interference environment is simulated and analyzed.The results show that the system has strong anti-jamming ability.Then,the signaling transmission protocol of OFDM-TDCS in cognitive radio scenarios is developed.Firstly,the single-user random access algorithm is studied,and the design scheme is given from the aspects of the establishment of communication links,the maintenance of broken chains and periodic maintenance.Secondly,the carrier interception multi-access algorithm is used to avoid collision in the complex communication environment of multi-users.Finally,the conflict in backoff mechanism is proposed.The corresponding solutions are given.Finally,OFDM-TDCS is implemented using software radio platform.The transmitter and receiver links of the system are designed and explained in detail,and the anti-jamming performance of OFDM-TDCS is tested.The results show that the system has a good anti-jamming ability,which is affected by the hardware platform.The measured performance is about 2dB worse than the simulation performance.