Research On SDMA Technology For Backscatter Communications

With extraordinary advantage of highly efficient utilization of spectrum and energy over traditional wireless communication,backscatter communication has received many attention recently.In this dissertation,we mainly focus on the multiple access problem of the backscat-ter communication system.The combination of SDMA and backscatter communication is presented as a promising solution for it.Then a Bistatic backscatter communication system with hybrid SDMA protocol is proposed.Backscatter access point(BAP)is able to receive multiple signals from backscatter nodes(BNs)and RF source,and make assessment of direction and angle of arrival for these RF uplinks.To achieve desired spatial beam pattern,beamforming coefficients need to be trained beforehand.Then we evaluate the performance of the proposed system and the bidirectional communication between BAP and BNs in Matlab.The system achieves BER on the order of 10-5 for both uplink and downlink at the rate of 1Mbps.The main contribution of this paper is that we propose an SDMA-based backscatter communication system which could improve network capacity,transmission delay and BER.Additionally,the BNs' complexity and system power consumption are reduced by the new hybrid protocol.