Sum-rate scheduling of decode-and-forward broadcast channel with limited-feedback

In wireless dual-hop decode-and-forward (DF) relaying networks, multiple relay stations (RS) and users construct a multiple-in-multiple-out (MIMO) broadcast channel (BC). Due to unpredictable decoding failure, scheduling the transmission for the decode-and-forward broadcast channel (DFBC) should depend on not only channel qualities but also the availability of errorless data at individual RSs. Based on the reception qualities of RSs and channel quality information (CQI), we propose a new centralized scheduling scheme to maximize the sum rate of the DFBC. An exact closed-form expression for the sum rate is derived to analyze the new scheme. Simulations demonstrate that the derived closed-form expression is able to quantify the proposed scheduling method accurately. It is also revealed that extra cooperative diversity can be exploited by employing the increased number of RSs, thereby improving sum rate.