Open AccessOptimization of Iterative Channel State Estimation Algorithms in SCMA System
Author(s) -
Vyacheslav P. Klimentyev,
Alexander B. Sergienko
Publication year - 2018
Publication title -
izvestiâ vysših učebnyh zavedenij rossii. radioèlektronika
Language(s) - English
Resource type - Journals
eISSN - 2658-4794
pISSN - 1993-8985
DOI - 10.32603/1993-8985-2018-21-3-23-34
Subject(s) - algorithm , spectral efficiency , channel (broadcasting) , computer science , iterative method , coding (social sciences) , mathematical optimization , mathematics , statistics , telecommunications
Optimization of iterative algorithms for channel state estimation in a sparse coding multiple-access system (SCMA) is performed to reduce computational costs of the receiver. It is shown that when a signal-to-noise ratio (SNR) does not exceed 10 dB, one iteration of the algorithm is sufficient, and an increase in the number of iterations does not lead to an increase in spectral efficiency. Simulation demonstrates a possibility of a reasonable choice of the total number of decoder iterations and their distribution between different stages of the channel estimation. For an uncoded system, iterative re-estimation of the channel is proposed, as well as ways to reduce computational costs during its calculation. In the coded system, at a low SNR the achieved spectral efficiency values are approximately similar to those with pilot-only channel estimation. The article provides recommendations for the placement of data symbols and pilot signals in re-source blocks to increase the system spectral efficiency.