Optimal User-Cell Association for 360 Video Streaming over Dense Wireless Networks

TL;DR

This paper addresses the challenge of optimizing user-cell associations for 360 video streaming in dense wireless networks, proposing algorithms that significantly enhance user experience and resource efficiency.

Contribution

It formulates the user-cell association and video multicasting as an NP-hard problem, and introduces two efficient approximation algorithms with near-optimal performance.

Findings

Algorithms improve user experience by 30%

Proposed methods are near-optimal in simulations

Addresses NP-hard problem with practical solutions

Abstract

Delivering 360 degree video streaming for virtual and augmented reality presents many technical challenges especially in bandwidth starved wireless environments. Recently, a so-called two-tier approach has been proposed which delivers a basic-tier chunk and select enhancement-tier chunks to improve user experience while reducing network resources consumption. The video chunks are to be transmitted via unicast or multicast over an ultra-dense small cell infrastructure with enough bandwidth where small cells store video chunks in local caches. In this setup, user-cell association algorithms play a central role to efficiently deliver video since users may only download video chunks from the cell they are associated with. Motivated by this, we jointly formulate the problem of user-cell association and video chunk multicasting/unicasting as a mixed integer linear programming, prove its NP-hardness, and study the optimal solution via the Branch-and-Bound method. We then propose two polynomial-time, approximation algorithms and show via extensive simulations that they are near-optimal in practice and improve user experience by 30% compared to baseline user-cell association schemes.