A limited feedback-based bit allocation method for interference alignment

While distract interference alignment needs ideal channel state information (CSI), it is difficult to achieve in real communication system. But reality communication system possesses feedback link. Based on this, interference alignment (IA) with limited feedback was proposed. Channel coefficient matrices is quantified at receivers, and then the precoding matrix will be designed with the quantified channel coefficient got in feedback scheme at transmitters. Then interference alignment can be achieved when perfect channel state information is not available. Consider the rate loss of the system caused by limited feedback, and the rate loss under the method of bit average allocation for interference alignment with limited feedback isn´t minimum, a new bit allocation method is proposed. The proposed scheme can improve the rate performance due to the rate loss is reduced. The simulation results showed that when the condition of interference alignment is satisfied, the proposed method can improve the sum rate of the system compared with the traditional interference alignment with limited feedback method.