Linear Precoded Cooperative Transmission Protocol for Wireless Broadcast Channels
In Multiple-Input and Single-Output (MISO) broadcast channels, the achievable diversity gain is limited by the number of source transmitter antennas. Cooperative transmission is able to provide another dimension of diversity gain improvement. In this paper, the authors introduce a spectral efficient cooperative transmission protocol in the MISO broadcast channels using linear precoding and non-orthogonal relaying. The proposed protocol can achieve maximum diversity gain expressed as a sum of the number of source transmitter antennas and the number of available relays. The diversity and multiplexing trade-off of the proposed protocol outperforms non-cooperative scheme, even when only single relay is used. For a large number of relay candidates, the diversity and multiplexing trade-off of the proposed protocol completely surpasses the existing non-cooperative scheme.