A Robust Ranging Scheme for OFDMA-Based Networks
Uplink synchronization in Orthogonal Frequency-Division Multiple-Access (OFDMA) systems is a challenging task. In IEEE 802.16-based networks, users that intend to establish a communication link with the base station must go through a synchronization procedure called Initial Ranging (IR). Existing IR schemes aim at estimating the timing offsets and power levels of Ranging Subscriber Stations (RSSs) without considering possible frequency misalignments between the received uplink signals and the base station local reference. In this work, the authors present a novel IR scheme for OFDMA systems where carrier frequency offsets, timing errors and power levels are estimated for all RSSs in a decoupled fashion.