Frequency selection strategies for hybrid TDD/FDD-CDMA cellular networks

Hybrid TDD/FDD-CDMA is an attractive technique for third generation cellular networks, in which FDD-CDMA is used to provide wide area voice and low bit-rate data services, and TDD-CDMA with limited coverage is used to provide high bit-rate asymmetric data services. In this paper, we propose two new frequency selection strategies to select the FDD-CDMA channel (forward link f_F or reverse link f_R ) for TDD-CDMA picocell operation in a FDD-CDMA macrocellular network. One is random selection strategy (RSS) which chooses f_F or f_R in a random fashion, and the other one is distance based selection strategy (DBSS) which applies a cell partitioning structure to divide each macrocell into an inner tier and an outer tier. With two separated carrier frequencies (f_F and f_R), the inner tier of each macrocell can use one of these two frequencies, while the outer tier can use the other one. The outage performance of the hybrid TDD/FDD-CDMA network employing the above strategies is studied through computer simulations