User Multiplexing in Relay Enhanced LTE-Advanced Networks

The 3^rd Generation Partnership Project has recently started the standardization process for LTE-Advanced, as a major evolution step of UTRAN LTE Release 8. One of the key enhancing technologies being studied that may help to fulfill the challenging performance targets of LTE-Advanced networks is radio relaying. This uses relay nodes that act as surrogate base stations for mobile users whose radio links with the base stations are not experiencing good enough conditions. In the downlink, the data that is destined for the relayed users may first have to be multiplexed by the base station, sent over the wireless backhaul link towards the relay node, and de-multiplexed and forwarded to the individual users by the relay node. The reverse process also has to be undertaken in the uplink. In this paper, we present a novel multiplexing scheme which is able to adapt the addressing and bitmapping of user identification to the actual number of users being served by the relay nodes, and thus greatly reduce the multiplexing overhead.