关键词: 多用户, MIMO系统, 机会通信, 反馈, 自适应

Abstract:

We introduce a double thresholds opportunistic transmission scheme in the multiuser MIMO downlink with limited feedback. In the strategy two thresholds are employed. In each time slot the mobile station (MS) whose channel gain exceeds the primary threshold is eligible for feeding back information and becomes the candidate which could be scheduled by the base station (BS). The secondary threshold is derived from the primary one and used for MS's transmission mode selection, including beamforming (BF) and spatial multiplexing (SM). With feedback information, the BS schedules one user out of candidate MSs. Theoretical analysis in company with Monte-Carlo simulation are employed. Results show that the scheme can effectively reduce the feedback load, achieve high system capacity and good outage performance.

Key words: multiuser, MIMO systems, opportunistic transmission, feedback, adaptation