Low complexity Turbo synchronization without initial carrier synchronization

摘要

Wireless data transmission results in frequency and phase offsets of thesignal in the receiver. In addition the received symbols are corrupted bynoise. Therefore synchronization and channel coding are vital parts of eachreceiver in digital communication systems. By combining the phase andfrequency synchronization with an advanced iterative channel decoder (innerloop) like turbo codes in an iterative way (outer loop), the communicationsperformance can be increased. This principal is referred to as turbosynchronization. For turbo synchronization an initial estimate of phase andfrequency offset is required. In this paper we study the case, where theinitial carrier synchronization is omitted and an approach with trialfrequencies is chosen. We present novel techniques to minimize the number oftrial frequencies to be processed. The communications performance and effortof our method is demonstrated. Furthermore the implementation complexity ofthe whole system is shown on a Xilinx FPGA.