Joint power allocation, precoding, and decoding method and base station thereof

Abstract

This invention provides a joint power allocation, precoding, and decoding method and a base station thereof. They are applicable to multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) systems. The method includes: (1) decomposing the precoder for each cluster into a first precoder and a second precoder; (2) obtaining the mean-squared error (MSE) functions of the decoded signals for all user equipment devices in each cluster; (3) calculating the power allocation factors for each cluster in the case of minimizing the maximum of all the MSE functions in each cluster; and (4) obtaining the second precoder and the decoders for each cluster in the case of minimizing a sum of the MSE functions of the decoded signals for all user equipment devices in all clusters under a total power constraint according to the power allocation factors.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority benefit of Taiwan application serial no. 106108456, filed on Mar. 15, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.BACKGROUND OF THE INVENTIONField of the Invention[0002]The invention relates to a joint power allocation, precoding, and decoding method and a base station using the same that are adapted to a downlink multiple input multiple output non-orthogonal multiple access (MIMO-NOMA) system.Description of Related Art[0003]Along with the development of technology, due to obvious improvement of a non-orthogonal multiple access (NOMA) system in capacity, NOMA has become a promising candidate for the next generation of wireless communication systems.[0004]In a NOMA system, user multiplexing can be implemented in the power domain of the transmitting end, and then the receiving end adopts a successive interfer...

AI Technical Summary

Benefits of technology

[0013]In an embodiment of the invention, the step of calculating the power allocation factor αk corresponding to each of the clusters based on minimizing the maximum of the first MSE function, the second MSE function, and the third MSE function in each cluster under a condition that the second precoder is given includes calculating the power allocation factor αk corresponding to each of the clusters based on minimizing the maximum of the first MSE function and the second MSE function in each cluster; and calculating the power allocation factor αk corresponding to each of the clusters based on minimizing the maximum of the first MSE function and the third MSE function in each cluster.

[0029]According to the above description, the embodiment of the invention provides a joint power allocation, precoding, and decoding method and a base station thereof. In the invention, a first precoder capable of cancelling inter-cluster interference is first obtained through the block diagonalization precoding technique to decompose MIMO-NOMA channels of multiple clusters into a plurality of parallel single-cluster MIMO-NOMA channels. Considering the MSE performance of the MIMO-NOMA system, two optimization problems for determining power allocation factors, second precoders, and decoders are successively customized to achieve a certain level of the MSE performance. Moreover, the final optimal power allocation factors, the final optimal second precoders, and the final optimal decoders are obtained through an iterative algorithm, so as to further improve the MSE performance. Overall, the performance of the MIMO-NOMA system can be effectively improved to provide better transmission quality.

Problems solved by technology

Therefore, how to indeed take the advantage of the spatial multiplexing and diversity gains in a MIMO-NOMA system to provide better system performance becomes an important issue in related fields.

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