Alan James Coulson, Waterloo (NZ); Chaturanga Pilane Lokuge, Tawa (NZ); Derek Bernard Richaedson, Belmot(NZ)
Industrial Research Limited, Parnell, Auckland (NZ)
The OFDM communications system for wireless networks includes at least one transmitter and at least one receiver. Each transmitter includes a signal source, a transmit modulator that arranges the data into packets and appends a pilot symbol of a repeated pseudo random binary sequence to the start of each packet, a multiplexer, an inverse fast Fourier transform, an up-sampler, a digital low pass filter, a digital to analogue converter, and an RF module. Each receiver includes an RF module, an analogue to digital converter, a digital low pass filter, a down-sampler, a frame detector to search for significant pilot symbol correlations and make initial estimates of at least one signal parameter, a digital phase locked loop to remove estimated frequency- and phase-offsets, a fast Fourier transform operator, a linear phase corrector to remove estimated sub-sample timing errors, a decision block, and a demultiplexer.