A low complexity cell search method for IEEE 802.16e OFDMA systems

Ranging is one of the most important processes in the uplink of the IEEE 802.16e OFDMA system. A ranging process includes initial ranging, periodic ranging, handover ranging, and contention bandwidth request. Initial ranging provides network entry, uplink synchronization, and system coordination. In the initial state of the transmission process, multiple users transmit randomly selected ranging code sets and BS identifies a specific user by using the ranging code identification and uplink synchronization by using the transmission delay estimation. In this paper, we discuss the details of initial ranging and propose an algorithm to carry out a successful ranging process. Performance results and the comparison of computational complexity with the traditional method are also presented. It is observed that the proposed algorithm can offer a better trade-off between computational complexity and performance.