On Synchronisation Issues in Wireless Mobile Digital Communications
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
Symbol timing recovery is an important function of any digital receiver. In the wireless mobile data field the task of establishing accurate symbol timing at the receiver is complicated by the time varying channel. This time varying channel also makes the use of coherent modulation schemes significantly more difficult. This is one of the major reasons that almost all existing mobile wireless digital standards utilise some form of differential modulation and detection. This thesis takes a primarily practical approach to the investigation of timing and phase estimation problems. The main focus of the work is on the comparison of three existing all digital timing synchronisation algorithms, two of which were originally designed for the AWGN channel, and the third was designed from ML principles for the Rayleigh fading channel. In order to test these sub-systems in the wider context of receiver performance, a pilot symbol assisted (PSAM) receiver was simulated to compare the effects of the different synchronisers on receiver steady state performance. Finally, because the real time implementation aspects of software radio are of considerable interest to the author, some attempt has been made to migrate the MATLAB synchronisation simulations to a real time DSP platform, specifically the TMS320C6701 Texas Instruments floating point device.