[Paper Review] A Multicast Approach for Constructive Interference Precoding in MISO Downlink Channel

Maha Alodeh, Symeon Chatzinotas+1 more|arXiv (Cornell University)|Jan 25, 2014

Advanced MIMO Systems Optimization6 references4 citations

TL;DR

This paper proposes a novel multicast-based precoding scheme for MISO downlink channels that exploits constructive interference by jointly leveraging data information (DI) and channel state information (CSI). Using a maximum ratio transmission (MRT)-based algorithm, it minimizes transmit power while enhancing SINR, outperforming state-of-the-art techniques through a formal duality between constructive interference and multicast channel formulations.

ABSTRACT

This paper studies the concept of jointly utilizing the data information(DI)and channel state information (CSI) in order to design symbol-level precoders for a multiple input and single output (MISO) downlink channel. In this direction, the interference among the simultaneous data streams is transformed to useful signal that can improve the signal to interference noise ratio (SINR) of the downlink transmissions. We propose a maximum ratio transmissions (MRT) based algorithm that jointly exploits DI and CSI to gain the benefits from these useful signals. In this context, a novel framework to minimize the power consumption is proposed by formalizing the duality between the constructive interference downlink channel and the multicast channels. The numerical results have shown that the proposed schemes outperform other state of the art techniques.

Motivation & Objective

• To address the problem of interference in MISO downlink systems by transforming it into constructive signal gain.
• To minimize transmit power consumption in MISO downlink by jointly utilizing data information (DI) and channel state information (CSI).
• To establish a formal duality between constructive interference channels and multicast channels for precoding design.
• To develop a practical, low-complexity precoding algorithm that improves spectral efficiency and energy efficiency.
• To outperform existing state-of-the-art precoding techniques in terms of power efficiency and SINR performance.

Proposed method

• Formalizes the duality between constructive interference downlink channels and multicast channels to enable power-efficient precoding.
• Proposes a maximum ratio transmission (MRT)-based algorithm that jointly exploits DI and CSI to align interference constructively.
• Designs a symbol-level precoder that ensures desired signals are maximized while interference is aligned to enhance SINR.
• Reformulates the power minimization problem as a multicast beamforming problem, enabling efficient solution via convex optimization.
• Employs a constructive interference constraint to ensure that interference from other streams enhances, rather than degrades, the desired signal.
• Uses a semidefinite relaxation approach to solve the non-convex optimization problem efficiently.

Experimental results

Research questions

• RQ1 Can constructive interference be systematically exploited in MISO downlink channels to improve spectral and energy efficiency?
• RQ2 How can data information (DI) and channel state information (CSI) be jointly utilized to design effective symbol-level precoders?
• RQ3 What is the mathematical duality between constructive interference channels and multicast channels in MISO systems?
• RQ4 Can power consumption be minimized while maintaining or improving SINR through constructive interference shaping?
• RQ5 How does the proposed MRT-based scheme compare to existing state-of-the-art precoding techniques in terms of performance and complexity?

Key findings

• The proposed scheme achieves significant power reduction compared to conventional interference-zero-forcing and energy-efficient precoding methods.
• Numerical results demonstrate that the proposed algorithm outperforms state-of-the-art techniques in terms of transmit power minimization.
• The duality between constructive interference and multicast channels enables a more efficient and tractable optimization framework.
• The MRT-based algorithm effectively aligns interference constructively, improving SINR without increasing transmit power.
• The scheme maintains low computational complexity while achieving superior performance in power efficiency.
• The framework is validated through simulations showing consistent gains across various channel conditions.