Coverage Extension and Power Allocation in Dual-Hop Space–Time Transmission With Multiple Antennas in Each Node

Wireless dual-hop relaying is envisioned to provide better coverage as well as signal reliability for existing single-hop wireless communication systems. The simplest feature of the dual-hop relay has attracted increasing interest from research and commercial communities. Emerging transmit diversity techniques using space-time transmission with multiple antennas could further enhance the dual-hop relaying performance. In this paper, we examine the coverage of dual-hop space-time relaying and allocation of limited power to the source transmitter as well as the relay. We finally compare different coverage-extension strategies, namely, increasing Tx power, employing multiple Tx antennas to achieve transmit diversity, and adopting either a nonregenerative relay or a regenerative one to enforce signal reliability at the destination. It is numerically shown that the space-time transmission that is used in the dual-hop relaying can further extend the coverage, although its performance depends on various parameters, namely, relaying methods, location of the relay, and power allocation.