Synchronisation Techniques

In systems with highly efficient turbo-codes, wherethe operating SNR may be as low as 1-2 dB, excellentestimation accuracy for synchronisation parametersis required. However, in such conditionsconventional non-data-aided synchronisationtechniques become difficult due to the low SNRs. Inaddition, to achieve a high efficiency, it isdesirable to recovery synchronisation from receiveddata signals without using preambles. This bookdescribes a novel concept, which is called a prioriprobability aided synchronisation. This concept fitsparticularly well with the iterative turbo decoder,but it will also be applicable with other types ofcode. The proposed synchronisation operatesiteratively and jointly with the turbo decoding,rather than separately prior to the decoding. Thisallows a successive refinement of synchronisationand provides reliable estimation and robust datadecoding against a wide range of synchronisationoffsets. It is shown that remarkableperformance approaching that of the data-aidedtechniques can be achieved using blindsynchronisation at low SNRs.