MIMO下行链路低反馈开销双阈值机会传输

Double-level threshold opportunistic transmission in MIMO downlinkwith reduced feedback

针对多用户多输入多输出(MIMO)下行链路,提出一种降低反馈开销的双阈值机会传输策略.该策略采用双阈值判断机制,其中严格阈值用于降低反馈开销,宽松阈值保证系统具有低的中断概率.在每个时隙,仅信道质量满足阈值要求的用户向基站反馈信息.基站根据所获信道信息从候选用户中选择一个进行通信.此外,各用户进行自适应通信方式,包括波束成形和空分复用,使反馈开销动态变化,有效利用发射功率,改善通信性能.理论分析和仿真结果表明,该策略能够显著降低反馈开销,获得高的吞吐量和好的中断性能.

A double-level threshold opportunistic transmission strategy in multiuser MIMO （MUMIMO） downlink with reduced feedback was proposed. With the scheme two thresholds were employed; the tight one was used for feedback load reduction, and the loose one was to guarantee low outage probability. In each time slot, only mobile station （MS） whose channel gain exceeds the threshold is eligible for feeding back information. The base station （BS） selects one user out of candidate MSs. Moreover, transmission mode adaptation, including beamforming （BF） and spatial multiplexing （SM） was implemented at each MS. Which results in various feedback cost, effective use of transmit power and communication performance enhancement. Statistical analysis and simulation resuits show that the proposed scheme can greatly reduce the feedback load and achieve high throughput as well as good outage performance.