Multipath streaming: fundamental limits and efficient algorithms

TL;DR

This paper analyzes the fundamental limits of multipath streaming, proposing simple, order-optimal algorithms without feedback, and provides bounds on starvation probability for various network delay models.

Contribution

It introduces fundamental limits and simple, feedback-free policies for multipath streaming, with tractable bounds applicable to diverse network scenarios.

Findings

Lower bounds on starvation probability established

Order-optimal policies without feedback proposed

Bounds tailored for different delay distributions and network types

Abstract

We investigate streaming over multiple links. A file is split into small units called chunks that may be requested on the various links according to some policy, and received after some random delay. After a start-up time called pre-buffering time, received chunks are played at a fixed speed. There is starvation if the chunk to be played has not yet arrived. We provide lower bounds (fundamental limits) on the starvation probability of any policy. We further propose simple, order-optimal policies that require no feedback. For general delay distributions, we provide tractable upper bounds for the starvation probability of the proposed policies, allowing to select the pre-buffering time appropriately. We specialize our results to: (i) links that employ CSMA or opportunistic scheduling at the packet level, (ii) links shared with a primary user (iii) links that use fair rate sharing at the flow level. We consider a generic model so that our results give insight into the design and performance of media streaming over (a) wired networks with several paths between the source and destination, (b) wireless networks featuring spectrum aggregation and (c) multi-homed wireless networks.