# Joint Fractional Time Allocation and Beamforming for Downlink Multiuser MISO Systems

## TL;DR

This paper proposes a joint fractional time allocation and beamforming approach for downlink multiuser MISO systems, enabling serving more users while preserving privacy and maximizing throughput.

## Contribution

It introduces a novel fractional time allocation scheme combined with beamforming, optimizing system throughput and user privacy in multiuser MISO systems.

## Key findings

- The proposed algorithm effectively increases the number of served users.
- Joint optimization improves system throughput significantly.
- Numerical results demonstrate the method's versatility and efficiency.

## Abstract

It is well-known that the traditional transmit beamforming at a base station (BS) to manage interference in serving multiple users is effective only when the number of users is less than the number of transmit antennas at the BS. Non-orthogonal multiple access (NOMA) can improve the throughput of users with poorer channel conditions by compromising their own privacy because other users with better channel conditions can decode the information of users in poorer channel state. NOMA still prefers that the number of users is less than the number of antennas at the BS transmitter. This paper resolves such issues by allocating separate fractional time slots for serving the users with similar channel conditions. This enables the BS to serve more users within the time unit while the privacy of each user is preserved. The fractional times and beamforming vectors are jointly optimized to maximize the system's throughput. An efficient path-following algorithm, which invokes a simple convex quadratic program at each iteration, is proposed for the solution of this challenging optimization problem. Numerical results confirm its versatility.