High Reliability Downlink MU-MIMO: New OSTBC Approach and Superposition Modulated Side Information

TL;DR

This paper introduces a novel OSTBC and superposition modulation approach to enhance the reliability of downlink MU-MIMO systems, allowing multiple users to share resources efficiently while improving error rates.

Contribution

The paper proposes a new OSTBC scheme combined with superposition modulation and side information for improved diversity and reliability in MU-MIMO systems, with detailed analysis and simulation results.

Findings

Significant reduction in block and frame error rates (BLER, FER).

Enhanced multiuser diversity through the new OSTBC approach.

Trade-off between reliability and data rate demonstrated.

Abstract

In this paper, a proposal to improve the reliability of a downlink multiuser (MU) MIMO transmission scheme is investigated with the use of a new approach in orthogonal space-time block codes (OSTBC) and network coding with a superposition modulated system and side information. With the new encoded OSTBC approach, diversity is offered where each user receives all other users' symbols, which allows the recovery of symbols in several ways. In addition, multiple users can be accommodated with the same resource, which is quite useful in a wireless system where resources are always restricted. By employing superposition modulation, the side information needed for error recovery can be transmitted over the same resource used for the normal information frame. In addition, the proposed system exploits diversity through a novel technique of sub-constellation alignment-based signal combining for efficient side information dissemination. A detailed analysis of the new OSTBC approach is carried out. It is shown that the performance of the MU-MIMO system can be improved significantly in terms of block and frame error rates (BLER, FER) considered as reliability measures. By accommodating a reasonable number of multiple users, high reliability is achieved at the expense of the rate. To compensate for the low rate, conventional OSTBC can be considered and simulation results are shown, where, as a penalty to pay, multiple orthogonal resources are required.