Power Allocation for Adaptive Asymmetric distributed MIMO Networks

Distributed MIMO network topology is one of the most promising technologies in modern communication networks. Compared to classical Single Input Single Output (SISO) links, where information is broadcasted from one sender over huge distances, the distance between two points in multi-hop networks is rather small. By means of such relay networks it becomes possible to guarantee a constant throughput while meeting a given end-to-end (e2e) outage constraint over extensive areas. In each hop several relay nodes form a virtual antenna array (VAA). By using this concept, capacity improving techniques like distributed space time codes can be implemented [Doh03]. The possibility of allocating recourses like transmit power is much more complex in distributed networks than in SISO links. The goal of power optimization in relay networks is to minimize the total transmit power while meeting a given e2e outage constraint. However, in practical scenarios, the structure of a relaying network does not have to follow certain geometrical regularities but can be arranged asymmetrically. As a consequence of that, the closed form expression of power allocation for asymmetric networks is intricate. In this paper the performance of power allocation for an adaptive asymmetric distributed relay networks is analyzed. The significant power saving compared to a non adaptive network is demonstrated by numerical calculations.