Base-station and subcarrier assignment in two-cell OFDMA downlink under QoS fairness

Consider the problem of base-station and sub-carrier assignment on the downlink of a two-cell OFDMA system with adaptive modulation. The aim is to maximize a common data rate that can be offered to each user with a guaranteed maximum rate-outage probability. A target bit-error rate is also guaranteed with a maximum outage probability. The channel model takes into account the propagation path-loss in addition to log-normal shadowing and Rayleigh fading. The channel-state information available about each user corresponds to the shadowed path-loss that we define. We use the well-known frequency-reuse partitioning as an inter-cell interference mitigation technique. We suggest a simple threshold-based method for optimizing the reuse scheme. This method allows us to transform the considered optimization problem into a tractable one that we resolve numerically. Simulation results allows us to validate the proposed method and to compare the average achieved performance to that obtained with static BS-assignment and/or static frequency-reuse scheme.