Coverage enhancement through two-hop relaying in cellular radio systems.

摘要

Relaying is found in Packet Radio and Ad-hoc networks whereby communications between mobile terminals are carried out in a distributed manner through intermediate relay nodes. When employed in a cellular network, this technique can be regarded as an Opportunity Driven Multiple Access (ODMA) scheme where relaying is turned to when communications to and from the base station for a certain mobile terminal are poor due to a lack of LOS (Line of Sight) or severe multipath fading.;There are many open challenges regarding this technology when incorporated into a cellular network, and they include: routing (or relay node/path selection) algorithms, channel allocation for relaying purposes, radio signal propagation characteristics between low height terminals, users' cooperation, and security. In this thesis, a simulation approach is taken to investigate the impact of different relay node/path selection and channel selection schemes (from among all employing channels already used in the adjacent cells) for relaying purposes on the users coverage, with and without power control. Our simulation results demonstrate that with a good relay node/path selection scheme and power control, relaying can have a significant improvement on the coverage. Furthermore, this improvement is quite insensitive to the channel selection schemes.