Cross-Layer Issues for Cooperative Networks

This paper deals with a cross-layer approach for cooperative diversity networks which use a combination of Amplify-and-Forward (AF) and Decode-and-Forward (DF) as a relaying strategy. Based on a well-selected ad-hoc configuration, the proposed approach combines the AF diversity concept with a simultaneous optimization of Physical, Network and Multiple Access Control layers. The considered optimization problem requires an appropriate distribution of three roles among the network nodes which are the diversity-relays (AF concept), the intermediate-router (DF and routing) and the destination (scheduling). The proposed role assignment is based on the instantaneous channel conditions between the links and jointly supports performance optimization and a long-term fairness concept. In order to minimize the required complexity, a partial and quantized channel feedback is also proposed. The proposed cross-layer solution is compared with conventional approaches by computer simulations and theoretical studies, and we show that it achieves an efficient performance-complexity trade-off.