Analysis of selection criteria for vector channels or orthogonal precoding matrices in communication systems with multiplexing
Mikhail G. Bakulin, Vitaly B. Kreyndelin, Andrey A. Reznev, NTC Atlas JSC · T-Comm - Телекоммуникации и Транспорт · 2025
Modern multiuser communication systems use various technologies for multiplexing symbol streams over multiple parallel channels (OFDM, MIMO). Channels with different types of multiplexing generally refer to vector channels. There is a problem of selecting the best vector channel for the user from the available set. When it is not possible to select a vector channel, the performance may be improved by using a precoding matrix that reallocates the streams across the subchannels. In this case, there is also a problem of selecting the best precoding matrix. Not always the traditional selection criteria used for scalar channels, such as, for example, maximum average SNR or maximum throughput capacity, provide the best choice in terms of data transmission quality. Several variants of known criteria for vector channel selection or orthogonal precoding are considered, and new empirical criteria are proposed. The mathematical modeling method analyzed the efficiency of using different criteria for the OFDMA communication system when selecting a set of subcarriers, as well as when selecting an orthogonal precoding matrix. Efficiency of using different criteria for an OFDMA communication system is analyzed via simulation, when selecting a set of subcarriers, as well as when selecting an orthogonal precoding matrix. The results of the analysis show that empirical criteria often give better results compared to traditional ones.