Delay-tolerant codes for the decode-and-forward cooperation in wireless networks. (c2009)

Abstract

With the great growth of wireless devices and communication, there is a huge demand for higher data rates. To respond to this growing demand, fourth generation (4G) wireless Local Area Networks (LANs) might adopt cooperation techniques where several collocated mobile terminals can cooperate with each other in order to enhance the quality of their corresponding communication links. One popular cooperation strategy is the Decode-and-Forward (DF) strategy. After a first phase where the source node broadcasts its message to the neighboring nodes (relays), these nodes will transmit their decoded versions of this message simultaneously to the destination. To conveniently encode the interfering data streams that are transmitted simultaneously from the different relays, Space-Time (ST) coding techniques must be applied. In this work, we propose a novel ST code that is adapted to the DF strategy with two relays. This code is tolerant to the delays that might occur between the different relays and it presents the main advantage of a reduced decoding complexity. In fact, only three data streams need to be decoded jointly rather than four streams as in the case of the existing solutions. An additional advantage is that the proposed code is totally real and, consequently, it is adapted to low cost carrier-less ultra-wideband transceivers that do not necessitate tracking the phase of the incoming signal.