Performance evaluation of Mesh-based mobile WiMax PHY baseband for above the sea propagation

In this paper, the performance evaluation of the Mesh-based PHY of IEEE 802.16e standard (a.k.a Mobile WiMax) for above the sea propagation is presented. For a Mesh OFDM system, the independent bursts transmission among different communicating nodes compels the receiving nodes to perform frame locking using the preamble with size of only one OFDM symbol interval, short preamble length is used in favour to good throughput rate. One-frame locking posts extra challenge to the hardware because dynamic and accurate synchronization algorithm is necessary. However, we used pulse-per-second (PPS) signal synchronization from Global Positioning System (GPS) to bring down the pulse-per-millions (ppm) error from 30 to 0.01 once course frame synchronization is achieved. We have proposed the modified preamble structure to perform timing synchronization. Next, the pilot tones within OFDM sub-carriers coupled with the linear interpolated channel estimation algorithm bring the phase error further down to give fairly good performance for OFDM system which is catered for Doppler fading criteria of up to relative speed 120km/h created by moving ships.