Outage probability for uplink of cellular OFDM-FDMA system

OFDM is a potential candidate for next generation air-interfaces. The intrinsic property of OFDM ensures that it can be used in a multiuser application to produce a highly flexible and cost-efficient communication system. In particular, the FDMA technique in combination with OFDM (OFDMA) is assumed in this paper. This allows for a high degree of bit-granularity, which is desirable for packet data services. In the past, the performance of such an air-interface was primarily investigated for a single cell scenario (hot spot). In this investigation the performance of OFDMA in a cellular environment with frequency reuse of one and non-perfect frequency synchronization is investigated. In particular the effects of co-channel interference (CCI) in the uplink is analysed since primarily this link direction is affected by asynchronous transmissions. Two kinds of power control methods have been implemented in this paper in order to combat the CCI and improve the spectrum efficiency. One is constant received power control (CRPC); the other is step removal algorithm C/I balancing power control (SRAPC). The performance measure is outage. The results show that outage probability is significant (up to 55%) for a two-cell case with CRPC. The results for a multiple-cell cluster are also shown in this paper.