An emerging concept for 4G+ wireless cellular networks: Terminal relaying

We identify relaying as one of the most effective and enabling components of the LTE-A standard. However, this standard suffers from a major weakness that results from the assumptions that the relaying nodes are static, their locations are known and their number is fixed. While these assumptions facilitate the design of the cellular system, they limit the scope of relay usability. As an alternative, we consider a cellular system in which the wireless terminals (WTs), in addition to transmitting their own signals, act as relays to assist other WTs. In such a system the number of relays scales with the number of WTs offering the system designer significantly more degrees of freedom. However, using WTs as relays presents a number of challenges, including: the mobility of the relaying WTs, the incidental manner in which the relays access the network, the resource blocks (RBs) to which each relay is entitled, the relaying mechanism used by each relay, and the way in which the power is allocated across frequency bands.