Research On Limited Feedback In Comp Systems

Coordinated multi-point (CoMP) and Limited feedback technologyare now qualified as the key technology of the fourth generation wirelesscommunication due to the advantages on improving the cellular edgeuser’s throughput and saving the feedback payload. Hence，we alwayscombine the limited feedback technology with CoMP technology, and byusing codebook quantization to save the feedback payload due to thelimited feedback and save the feedback payload in multi-cell system. Forpromising the superiority of CoMP system，efficient limited feedbackstrategy becomes one of the hot research focuses.We first consider the user feedback bits allocation in coordinatedscheduling system. In multi-cell system, we propose a joint adaptivefeedback scheme based on power allocation to reduce the inter-userinterference and inter-cell. According to the transmission channel gainand the interference channel strength，we analysis the rate loss due to thequantization error. Simulation results show that the proposed schemecompared with the traditional scheme remarkably improves the systemthroughput performance without increasing the feedback overhead..Since the practical CoMP channels may encounter server fading，packet transmission may appear to fail. If the receiver fails to decode apacket correctly，we can use Automatic Repeat Request technique toimprove the packet error by retransmitting the same packet. In this paperwe consider a limited feedback multi-cell multi-user CoMP systemequipped with ARQ，we propose an adaptive limited feedback allocationscheme based on ARQ technique. When some users need to retransmitthe packets，to maximize the sum capacity during each transmissiontime-slot, according to the transmission states of users，the availablequantization bits are dynamically allocation to different users in each cell.Simulation results show that the proposed scheme remarkably improvesthe system throughput performance when the pass-loss is very large. In this dissertation, following the standardization of the fourthgeneration wireless network, we have achieved some achievements on thelimited feedback in CoMP system，we propose a joint adaptive feedbackscheme based on power allocation, also we propose an adaptive limitedfeedback allocation scheme based on ARQ technique.