uStash: a Novel Mobile Content Delivery System for Improving User QoE in Public Transport

TL;DR

uStash is a new mobile content delivery system designed for public transport that improves user experience by reducing access delays and costs through collaborative caching and probabilistic modeling.

Contribution

It introduces a novel content distribution system leveraging spatial-temporal content popularity and connectivity, with analytical modeling and real-world validation.

Findings

Reduces cellular data costs by approximately 50%.

Decreases content access delay by around 60%.

Validated with real-life inter-city bus and mobile VoD datasets.

Abstract

Mobile data traffic is growing exponentially and it is even more challenging to distribute content efficiently while users are "on the move" such as in public transport.The use of mobile devices for accessing content (e.g. videos) while commuting are both expensive and unreliable, although it is becoming common practice worldwide. Leveraging on the spatial and temporal correlation of content popularity and users' diverse network connectivity, we propose a novel content distribution system, \textit{uStash}, which guarantees better QoE with regards to access delays and cost of usage. The proposed collaborative download and content stashing schemes provide the uStash provider the flexibility to control the cost of content access via cellular networks. We model the uStash system in a probabilistic framework and thereby analytically derive the optimal portions for collaborative downloading. Then, we validate the proposed models using real-life trace driven simulations. In particular, we use dataset from 22 inter-city buses running on 6 different routes and from a mobile VoD service provider to show that uStash reduces the cost of monthly cellular data by approximately 50\% and the expected delay for content access by 60\% compared to content downloaded via users' cellular network connections.