Cooperative transmission method based on dynamic swipt in downlink noma communication system

Abstract

The invention discloses a cooperative transmission method based on dynamic SWIPT in a downlink NOMA communication system, which divides the system transmission cycle T into two stages, the time of the first stage is (1-α)T, and the time of the second stage is αT; In the first stage, the near-end user receives the radio frequency signal of the base station, and divides the radio frequency signal into two parts. The power ratio of the first part is β, which is used for energy collection by the near-end user, and the second part is 1‑β. It is used for the near-end user to decode user information, while the far-end user receives the base station signal; in the second stage, the near-end user acts as a relay to transmit information to the far-end user, and the far-end user decodes the signal by selecting the combination technology; the time allocation coefficient α and power distribution coefficient β are determined by solving an optimization problem. The present invention dynamically adjusts the time distribution coefficient and the power distribution coefficient, balances the data rate difference between the near-end user and the far-end user in real time, and realizes the maximum total data rate of the communication system at the same time.

Description

technical field [0001] The invention belongs to the technical field of NOMA communication systems, and more specifically relates to a dynamic SWIPT-based cooperative transmission method in a downlink NOMA communication system. Background technique [0002] Non-orthogonal Multiple Access (NOMA) is a hot technology of 5G. NOMA is different from the previous multiple access technology. NOMA uses non-orthogonal power domain coding technology to distinguish users. The so-called non-orthogonal means that the data of different users can be transmitted on the same time slot and frequency. Only rely on the difference in data encoding power to distinguish users. [0003] According to the research, in the downlink NOMA communication system, the distance between the users in the cell and the base station will lead to obvious data rate differences, that is, the data rate of the near-end users (closer to the base station) is better, while the data rate of the far-end users (closer to the...

AI Technical Summary

Problems solved by technology

However, in existing studies, the time allocation coefficient in the SWIPT protocol is fixed (usually set to 0.5), and only the power allocation coefficient is optimized and analyzed. This method has a limited effect on improving the data rate of remote users, and cannot Further research is needed to fully improve the data rate fairness between two users

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