In this paper we propose a serial-parallel correlator (SPC) for the purpose of PN code acquisition in a low earth orbit (LEO) satellite environment. To reduce the effect of severe Doppler in a LEO satellite channel, we combine the SPC with an FFT technique to combat the carrier frequency offset due to Doppler shift. By using the FFT technique we omit the need for an additional search over the f...

Orthogonal Frequency-Division Multiple Access (OFDMA) is a multi-user version of the Orthogonal frequency-division multiplexing (OFDM). OFDMA is used in the mobility mode of IEEE 802.16 WirelessMAN Air Interface standard, commonly referred to as WiMAX. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users [1], [2]. The performance of these systems depend o...