Terminal relaying for future wireless networks

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Since their inception, cellular systems have assumed a leading role in the wireless communications industry which lies at the forefront of industrial, social and economical progress of our society. Cellular systems have undergone categorical evolution from analogue high-power first generation (1G) systems all the way to current fourth generation (4G) systems, which have been envisioned to provide ubiquitous network coverage and reliable transfer of high data rates. The technological foundation of 4G systems is provided in the Long Term Evolution Advanced (LTE-A) standards. One of the key elements supported by these standards is the utilization of intermediate wireless communication-assisting nodes, known as relays. Under ideal conditions it has been prospected that the deployment of relays will enhance network coverage and enable wireless terminals to operate at unprecedented data rates. Despite the great expectations, practical field tests indicate that slight deviations from the LTE-A ideal conditions result in significant loss in achievable rates and service coverage. **The goal of the research directions outlined in this proposal is to mitigate the pitfalls encountered in the practical field tests of current LTE-A based cellular systems. In LTE-A the relaying nodes are assumed to be static, their locations are known and their number is fixed. These assumptions limit the scope of relay usability, and to circumvent them, we will consider cellular systems in which idle terminals act as relays to assist active and other relaying terminals. In such systems the number of relays scales with the number of wireless terminals, thereby offering a significantly higher number of design degrees of freedom, but, at the same time presenting several serious challenges including the mobility of the relaying terminals and the random manner in which they access the network. **The focus of the proposed research directions is to explore and exploit the potential advantages offered by terminal relaying schemes and to address the challenges that impede their deployment in future wireless networks. We will proceed along four distinct axes. *1- Generalization and unification of currently available relaying mechanisms to enable smooth adaptation to the time-varying conditions of wireless channels.*2- Developing efficient signalling and detection techniques for terminal relaying systems with multiple transmit and receive antennas in the absence of perfect information about the underlying wireless channels.*3- Developing distributed design techniques that enable wireless systems with terminal relays to achieve high data rates and ubiquitous coverage at low computational and operational costs.*4- Developing techniques for designing multiple communication aspects of the wireless network concurrently, thereby enabling efficient utilization of the radio resources available for communication. **From a technical perspective, the successful completion of the proposed research plan is expected to provide a foundation for terminal relaying for beyond 4G cellular networks. From a national perspective, this proposal counts among the ambitious efforts to maintain Canada's international leading role as a key player in the vital industry of telecommunications.