Single-phase feedback and scheduling algorithm for MIMO broadcast system for excelling sum-rate capacity

Abstract

This work proposes a strategic single-phase feedback and scheduling algorithm basing upon semi-orthogonal user selection with zero-forcing beam forming. Zero-forcing beam- forming is a spatial signal processing method in order to avoid hindrance among users. For a downlink system, the ZFBF algorithm allows a transmitter to send data to the desired users together. This paper uses semi-orthogonal user algorithm (SUS), with the feedback of all user channel information, along a base station device. Thus, the response overhead increases significantly with the users in order to decrease the feedback load and it fully exploits the signal-to-interference-with-noise ratio (SINR) preserving orthogonality at all the stages. Accordingly, in this way a specific section of users provide feedback to their channel information. Further, the sum-rate capacity is theoretically investigated. We found that there is an improvement of sum-rate capacity considering feedback bits fixed, with an increase in the number of users.