Research On MIMO Wireless Network Scheduling Based On Interference Cancellation

Higher performance of communication technology is demanded for the rapid development of wireless communication networks.MIMO(Multiple-Input Multiple-Output)technology can transmit multiple data streams simultaneously without the bandwidth or transmission power increasing,and improve the throughput significantly.So it has attracted more and more attention.In MIMO wireless networks,the MIMO gain is closely related to the link scheduling.Link scheduling is to select the subsets which can be transmitted simultaneously in a given set of wireless links.Due to the cumulative interference effect of links,the network transmission power largely depends on the SINR(Signal to Interference plus Noise Ratio)value of the coupled links.And the link interference is the main factor limiting the performance improvement of link scheduling.Two common ways to deal with interference are interference avoidance and interference cancellation.The former one divides the links into independent channels by means of frequency division multiple access or time division multiple access to avoid interference.The latter one precodes and decodes the mixed signals to eliminate the interference using nodes.SIC(Successive Interference Cancellation)is an effective technology of multi-packet reception for interference cancellation.It decodes iteratively based on mixed signals received at the receiver.Based on the research results at the present stage,in this thesis,the single-slot link scheduling problem in MIMO wireless networks based on interference cancellation is studied with the fundamental of SINR model.This contributions of this thesis mainly includes two contents:(1)The MSIC link scheduling algorithm in MIMO wireless networks under SINR model is proposed.Firstly,the MSIC model is built based on SIC technology,and a mathematical framework is established for the cross-layer optimization of scheduling,with constraints of traffic balance and link capacity.Then,due to the global characteristic of the interference,it is considered to localize the interference and divide the interference regions.Finally,a distributed link scheduling algorithm based on MSIC to eliminate the interference between competing links is proposed.Experimental results show that the MSIC algorithm can increase the end-to-end throughput per unit about 73% on average compared with the non-SIC algorithms.(2)The DoF-SIC link scheduling algorithm in MIMO wireless networks under SINR model is proposed.Although the MSIC algorithm can improve network throughput,it satisfies the SINR threshold as a premise,that is,the decoding of weak signals is premised on the successful decoding of all strong signals.When the SINR value is less than the current threshold,considering the advantages and disadvantages of SIC and DoF IC technologies,DoF constraint is introduced on the basis of MSIC model,and a link scheduling algorithm combining DoF and SIC is proposed.On the one hand,when the threshold is satisfied,SIC is used to eliminate interference and DoFs resources are saved.On the other hand,DoF is used to eliminate the stronger interference in the SIC decoding process,in order to reach the threshold condition of SIC decoding.Based on the above ideas,firstly,signals from different senders are classified and different operations are performed on the signals in different sets.Secondly,a mathematical model is constructed to couple the DoF protocol model with the SIC physical model.Finally,the DoF-SIC link scheduling algorithm is proposed to improve the MSIC algorithm.Experimental results show that the DoF-SIC algorithm can achieve mutual benefits between DoF and SIC.