| ABSTRACT: As one of the leading digital trunked communication standards in the world, TETRA is considered as the most powerful commanding and dispatching digital trunked system. TETRA Release2enhanced functions of high speed data, speech codec and coverage area, and added a new channel coding scheme. TETRA is widely applied in the field of specialized dispatching communication throughout China. However, TETRA systems using in Chian are usually imported at high price from abroad by whole set. In order to promote the state-owned industrialization of TETRA system, channel coding scheme in TETRA Release2is chosen as the topic of this paper. The paper researches on access network system which measures up to TETRA standard, and is looking forward to provide valuable references on TETRA network planning and construction in the future.TETRA Release2adopted RCPC/PCCC coding schemes, which are fully compatible with the RCPC scheme using in TETRA Release1.For RCPC scheme, the paper researches on the principle and procedure of channel decoding. And through analysis of decoding algorithm, it also acquires the depth of traceback, the code rate of puncturing and other critical parameters which affect the performance of system error-correcting. Recommended values for the mentioned parameters are also raised.For the new added PCCC coding scheme in TETRA Release2, the paper researches the iterative decoding structure and SOVA decoding algorithm, and compares HR-SOVA with BR-SOVA algorithm. It provides a simulation method of the PCCC coding/decoding process, and compares and analyzes the decoding performance from the aspects of the different logic channels, frame length, punctured rate and decoding iterations. Parameter optimizations in various conditions are also proposed.At last, the paper proposes the design scheme of channel coding based on GNU Radio platform for TETRA. And the establishing methods of channel coding modules on GNU Radio platform are described in detail. |
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