Optimal Bandwidth Allocation for Multicast-Cache-Aided on-Demand Streaming in Wireless Networks

TL;DR

This paper proposes an optimized hybrid multicast-unicast streaming scheme for wireless networks that balances resource consumption and service outage probability, outperforming existing methods.

Contribution

It introduces a joint optimization framework for cache placement, resource allocation, and beamforming in a hybrid multicast-unicast system for wireless streaming.

Findings

Hybrid scheme reduces resource usage compared to traditional methods.

Optimized traffic offloading improves service reliability.

Simulation confirms better resource-outage tradeoff.

Abstract

We consider a hybrid delivery scheme for streaming content, combining cache-enabled Orthogonal Multipoint Multicast (OMPMC) and on-demand Single-Point Unicast (SPUC) transmissions for heterogeneous networks. The OMPMC service transmits cached files through the whole network to interested users, and users not being satisfied by this service are assigned to the SPUC service to be individually served. The SPUC fetches the requested files from the core network and unicasts them to UEs using cellular beamforming transmissions. We optimize the delivery scheme to minimize the average resource consumption in the network. We formulate a constrained optimization problem over the cache placement and resource allocation of the OMPMC component, as well as the multi-user beamforming scheme of the SPUC component. We apply a path-following method to find the optimal traffic offloading solution. The solutions portray a contrast between the total amount of consumed resources and service outage probability. Simulation results show that the hybrid scheme provides a better tradeoff between the amount of network-wide consumed resources and the service outage probability, as compared to schemes from the literature.