Dynamic Subcarrier, Bit and Power Allocation in OFDMA-Based Relay Networks
Christian L. Müller, Anja Klein, Frank Wegner, Kuipers, Martin · TUbilio (Technical University of Darmstadt) · 2007
In this paper, the downlink of a cell is con- sidered in an OFDMA-based relay network. In the cell, a base station (BS) and fixed relay stations (RSs) are deployed. Multiple subscriber stations (SS) are located in the cell. A SS is served either by a direct or a two hop connection. In a direct connection, a link between BS and SS exists. In a two hop connection, a link exists between BS and RS and between RS and SS. Using instantaneous channel state information, a method for resource allocation is presented which dynamically allocates subcarriers, bits and power to the existing links. An optimization problem is formulated aiming at the minimization of the power required for the transmissions of the BS and the RSs. The optimization problem is subject to a requested data rate on each link. The constraint is considered that a RS cannot transmit and receive simultaneously in order to avoid strong intercarrier interference. The evaluation of the presented resource allocation method shows that the required power is near to the theoretical minimum value and is lower than the power required by static resource allocation methods in a defined scenario of a relay network.