On the cellular spectral efficiency of MC-CDMA systems with MMSE multiuser detector employing fractional and soft frequency reuse

In this paper, an approach to evaluate the cellular spectral efficiency of the uplink of MC-CDMA systems employing fractional frequency reuse (FFR) and soft frequency reuse (SFR) is proposed. For this, an algorithm to calculate the cell coverage radius assuming the use of adaptive modulation is proposed. Then, expressions to evaluate the mean spectral efficiency of the cellular system are derived, which are function of the cell coverage radius, the number of users and the spreading factor. The analysis proposed in this paper allows to find operating scenarios that maximize the cellular spectral efficiency at the same time that a certain quality of service based on a target bit error rate (BER) is guaranteed for MC-CDMA systems. Specifically, this analysis considers the uplink of MC-CDMA systems employing a minimum-mean-square error (MMSE) multiuser detector and an antenna array at the base stations. Additionally, the presence of own-cell and co-cell interference is assumed in the channel model.