Coverage Enhancement Through Peer-to-Peer Relaying in Cellular Radio Networks

 We consider a TDMA cellular multihop network where relaying – via wireless terminals that have a good communication link to the base station – is used as a coverage enhancement technique. Provided that the subscriber density is not very low, relaying via wireless terminals can have a significant impact on coverage, capacity, and throughput. This is mainly due to the fact that the signals only have to travel through shorter distances and/or improved line-of-sight paths. In this work, we investigated the effects of various relaying node selection (essentially a routing issue) and relaying channel selection schemes, as well as the effects of transmit power control, on system performance (these three selection/control schemes constitute the three major radio resource management decisions in peer-to-peer relaying in cellular networks). Our results show that with some modest intelligence incorporated in the relaying node selection scheme, the system coverage can be improved significantly through two-hop relaying. Furthermore, this improvement is observed to be fairly insensitive to the relaying channel selection scheme used, which is a plus in implementation. It is also observed that, as long as the number of wireless terminals in a cell is not very low, a minimal relaying node power level is sufficient to obtain most of the coverage enhancements.