[Paper Review] Non-orthogonal Multiple Access for High-reliable and Low-latency V2X Communications in 5G Systems

Boya Di, Lingyang Song+2 more|arXiv (Cornell University)|May 24, 2017

Wireless Body Area Networks73 citations

TL;DR

This paper proposes a non-orthogonal multiple access (NOMA)-based two-fold scheme for 5G V2X networks, combining centralized semi-persistent scheduling with distributed power control to reduce access latency and improve reliability. The scheme models resource allocation as a multi-dimensional stable roommate matching problem and introduces a rotation matching algorithm that achieves L-rotation stable matching, outperforming orthogonal multiple access in latency and packet reception probability.

ABSTRACT

In this paper, we consider a dense vehicular communication network where each vehicle broadcasts its safety information to its neighborhood in each transmission period. Such applications require low latency and high reliability, and thus, we exploit non-orthogonal multiple access to reduce the access latency and to improve the packet reception probability. In the proposed two-fold scheme, the BS performs semi-persistent scheduling and allocates time-frequency resources in a non-orthogonal manner while the vehicles autonomously perform distributed power control with iterative signaling control. We formulate the centralized scheduling and resource allocation problem as equivalent to a multi-dimensional stable roommate matching problem, in which the users and time/frequency resources are considered as disjoint sets of objects to be matched with each other. We then develop a novel rotation matching algorithm, which converges to an $L$ -rotation stable matching after a limited number of iterations. Simulation results show that the proposed scheme outperforms the traditional orthogonal multiple access scheme in terms of the access latency and reliability.

Motivation & Objective

• Address the high reliability and low latency requirements of safety-critical V2X communications in dense vehicular networks.
• Reduce access latency and improve packet reception probability in time-constrained vehicular environments.
• Design a joint scheduling and resource allocation mechanism that supports high spectral efficiency and robustness.
• Develop a scalable and convergent algorithm for centralized resource allocation in non-orthogonal access scenarios.
• Enable distributed power control at vehicles to maintain performance under dynamic network conditions.

Proposed method

• Model the centralized scheduling and resource allocation problem as a multi-dimensional stable roommate matching problem involving vehicles and time-frequency resources.
• Propose a novel rotation matching algorithm that converges to an L-rotation stable matching in a limited number of iterations.
• Implement semi-persistent scheduling at the base station to minimize signaling overhead and reduce latency.
• Enable vehicles to perform autonomous distributed power control with iterative signaling control to maintain link quality.
• Use non-orthogonal resource allocation to allow multiple vehicles to share the same time-frequency resources, increasing spectral efficiency.
• Ensure stability and convergence of the matching process through iterative rotation-based reassignment of resources.

Experimental results

Research questions

• RQ1 How can non-orthogonal multiple access be effectively applied to reduce access latency in dense V2X networks?
• RQ2 What is the impact of a stable matching-based resource allocation framework on reliability and spectral efficiency in V2X communications?
• RQ3 Can a rotation-based matching algorithm achieve convergence to a stable solution with limited iterations in a dynamic vehicular environment?
• RQ4 How does the proposed two-fold scheme (centralized scheduling + distributed power control) compare to traditional orthogonal multiple access in terms of latency and reliability?
• RQ5 What is the performance gain of the NOMA-based scheme in terms of packet reception probability under high vehicle density?

Key findings

• The proposed NOMA-based scheme significantly reduces access latency compared to traditional orthogonal multiple access in dense vehicular networks.
• The rotation matching algorithm converges to an L-rotation stable matching within a limited number of iterations, ensuring practical deployment feasibility.
• The scheme improves the packet reception probability due to efficient non-orthogonal resource sharing and stable user-resource pairing.
• Simulation results confirm that the proposed method outperforms orthogonal multiple access in both latency and reliability metrics.
• The integration of semi-persistent scheduling and distributed power control enhances system stability and reduces signaling overhead.
• The multi-dimensional stable roommate matching formulation effectively models the complex interplay between vehicles and time-frequency resources in V2X scenarios.