Mobile Wireless Access via MIMO Relays

While a network with stationary nodes can provide large capacity in many current wireless systems, a network with mobile users suffers from severe performance degradation. This happens due to quick channel variation and its resulting protocol overheads that are especially large for multiuser multiple-input multiple-output (MIMO) systems. In this paper, we propose a relay-assisted multiuser MIMO downlink system to support highly mobile wireless access. Through a theoretical throughput analysis that explicitly considers the protocol overheads, we show that the MIMO relay significantly enhances the sum throughput of the system. While the introduced hardware complexity improves the throughput in low and moderate SNR regime, the throughput is improved by relay scheduling for spatial reuse in high SNR regime. We also discuss the practicality of this approach, characterizing challenging open problems in practice. Applications such as mobile video delivery can benefit from the enhanced system performance by our proposed architecture.