Concepts of the physical level of the fifth generation communications systems

Аннотация

The most promising technologies of signal forming and multiple access have been considered from the viewpoint of bandwidth-time resource usage. They include the full duplex technology, subcarrier forming method using a comb filter bank, the non-orthogonal multiple access method, and the sparse code multiple access method. The main existing implementation schemes of full duplex communication based on the analog and digital proper transmitter in the reception channel are described. The filtering multifrequency signal system using a bank of comb filters is considered. The spectrum of such signal is shown to have a much weaker out-of-band radiation as compared to the existing subcarrier forming techniques. The non-orthogonal multiple access method and the sparse code multiple access method are investigated, and relationships of the bit error rates as a function of the signal-to-noise ratio for communications systems based on these methods are presented. It has been shown that the multiple access methods under consideration are more effective in the bandwidth-time resource usage as compared to the existing technologies.