Near-Instantaneously Adaptive Cooperative Uplink Schemes Based on Space-Time Block Codes and V-Blast

In this paper we propose two adaptive schemes for improving the achievable bandwidth efficiency (BE) of cooperative diversity aided wireless networks. These schemes are capable of accommodating the channel signal-to-noise ratio (SNR) variation of wireless systems by near-instantaneously adapting the uplink transmission configuration. Explicitly, the first adaptive transmission scheme is constituted by a novel reconfigurable four-antenna-aided cooperative uplink space-time block coded (STBC) structure designed for communicating with a base station (BS) equipped with a single receive antenna. By contrast, the second adaptive scheme is constituted by a reconfigurable cooperative uplink vertical Bell Labs layered space time (V-BLAST)-like architecture constituted by single-antenna-aided mobiles communicating with a BS equipped with multiple receive antennas. Our results demonstrate that significant effective BE improvements can be achieved by both systems, while maintaining a target bit-error-ratio of 10^-3. Explicitly, when neglecting the Nyquist excess bandwidth, the first system is capable of attaining an effective BE varying between 0.316 bits/sec/Hz and 2.18 bits/sec/Hz, while the second has a BE varying between 2 bits/sec/Hz and 8 bits/sec/Hz.