Abstract
Relay-based transmission can over the benefits in terms of coverage extension as well as
throughput improvement if compared to conventional direct transmission. In a relay enhanced
cellular (REC) network, where multiple mobile terminals act as relaying nodes (RNs),
multiuser diversity gain can be exploited. We propose an efficient relaying scheme, referred to
as Broadcast Reserved Opportunity Assisted Diversity (BROAD) for the REC networks.
Unlike the conventional Induced Multiuser Diversity Relaying (IMDR) scheme, our scheme
acquires channel quality information (CQI) in which the destined node (DN) sends pilots on a
reserved radio resource. The BROAD scheme can significantly decrease the signaling
overhead among the mobile RNs while achieving the same multiuser diversity as the
conventional IMDR scheme. In addition, an alternative version of the BROAD scheme,
named as A-BROAD scheme, is proposed also, in which the candidate RN(s) feed back
partial or full CQI to the base station (BS) for further scheduling purpose. The A-BROAD
scheme achieves a higher throughput than the BROAD scheme at the cost of extra signalling
overhead. The theoretical analysis given in this paper demonstrates the feasibility of the
schemes in terms of their multiuser diversity gains in a REC network.