Research On The Interference Alignment Under Imperfect Channel State

Interference alignment was proposed as an effective means to mitigate interference in K-user interference channels.By aligning the interference from different transmitters into a lower dimensional subspace at each receiver,interference can achieve the optimal capacity scaling with respect to SNR.However,most existing interference alignment designs require full channel state information at transmitters.Such full channel state information requirement is quite difficult to achieve in practice due to limited CSI feedback capacity in the reverse link in practice.Therefore the research for a non-interfering channel information under alignment techniques has practical significance.For imperfect channel state information,divide the channel into delayed channel state information and a completely no channel information.And the delayed channel state information is divided into complete and partial delayed channel state information.Firstly,the completely stale transmitter channel state information is studied and the results have proved the use of these delayed channels state information can align the interference.The simulation of degrees of freedom reveals that a higher degrees of freedom is obtainable by using interference alignment technology to eliminate interference even without immediate channels state information.Secondly,the space-time interference alignment technique is concretely studied for the partial feedback delay of channel state information.This technology utilizes timely information and part of the delay feedback,and then alignments and eliminates interference.This paper proposed an interference alignment algorithm for the multi-cell with partial delayed channel state information and gained high degrees of freedom.Finay,in the case of completely non-ideal channel information status,this paper mainly focused on transmitting and receiving unknown channel state information.Several methods of blind interference alignment technology were studied to obtain the relevant principles and then the simulation results were analyzed to compare the difference among the methods.