Multiuser Two-Way Relaying Schemes for UWB Communication

In this paper, we propose multiuser two-way relaying strategies for pairwise internode communication in a network consisting of ultrawideband transceivers with limited signal processing capability, via a central relay unit. We propose reducing the complexity associated with the design of filters at the relay by using pre/post-rake processing in conjunction with optimized filtering at the relay. Two relaying strategies relevant to multipath fading channels, namely, detect-and-forward and filter-and-forward with self-interference cancelation, are considered. For both methods, we start with a convex optimization problem formulation with closed-form solutions, then extend the design to the more general case, which is a nonconvex problem, and use an alternating optimization algorithm to solve the design problems. Furthermore, for both design schemes, widely linear design formulations are devised. The presented numerical results demonstrate the capability of the proposed design schemes in establishing a reliable communication link between nodes with limited signal processing power and in the absence of a direct link.