HybCAST: Rich Content Dissemination in Hybrid Cellular and 802.11 Ad Hoc Networks

Abstract

We design, implement, and evaluate a middleware system, HybCAST, that leverages a hybrid cellular and ad hoc network to disseminate rich contents from a source to all mobile devices in a predetermined region. HybCAST targets information dissemination over a range of scenarios (e.g., military operations, crisis alerting, and popular sporting events) in which high reliability and low latency are critical and existing fixed infrastructures such as wired networks, 802.11 access points are heavily loaded or partially destroyed. HybCAST implements a suite of protocols that: (i) structures the hybrid network into a hierarchy of two-level ad hoc clusters for better scalability, (ii) employ both data push and pull mechanisms for high reliability and low latency dissemination of rich content, and (iii) implement a near-optimal gateway selection algorithm to minimize the transmission redundancy. To demonstrate its practicality and efficiency, we have implemented and deployed the HybCAST middleware on several Android smartphones and an in-network Linux machine that acts as a dissemination server. The system is evaluated via real experiments using a UMTS network and extensive packet-level simulations. Our experimental results from a live network show that HybCAST achieves 100% reliability with shorter latencies and lower overall energy consumption. Simulation results confirm that HybCAST outperforms other state-of-the-art systems in the literature. For example, HybCAST exhibits a 5 times reduction in the dissemination latencies as compared to other hybrid dissemination protocols, while its energy consumption is a third of a cellular-only dissemination system. Furthermore, the simulation results demonstrate that HybCAST scales well and maintains good performance under varying numbers of mobile devices, diverse content sizes, and device mobility.

Social Media Alert and Response to Threats to Citizens

“…medium access and network layers of the ISO stack). More recent efforts aim to use middleware driven approaches to manage communication by exploiting and merging multiple networking technologies such as mesh network deployments, delay tolerant networks, and mobile adhoc networks [36,37,38,39]. The ability to create spontaneous networks where nodes have the ability to make communication decisions locally, using available knowledge of network status and taking into account information needs and tolerance parameters (timing, accuracy, reliability) is critical to enabling communication resilience.…”

Rich content sharing in mobile systems using multiple wireless networks

“…While the cellular network provides a high reliability because it covers a large area, this approach does not disseminate as fast as expected because the server has to deliver members one by one and the cellular network has low capacity. In our middleware based approach [16], we employ a WiFi ad hoc network interface to augment the cellular network for faster content distribution.…”

“…In this paper, we address the problem of efficient rich content sharing from/to mobile devices by proposing practical approaches that provide high delivery performance, reduce cellular data traffic, and release the pressure of cellular networks' heavy load on mobile users and cellular network services providers. Our approaches [13][14][15][16] all share a common technique: using complementary networks, such as WiFi, WiFi ad hoc or Bluetooth, equipped in most modern mobile devices to offload data traffic previously planned to be transmitted over cellular networks. For each proposed approach, we prove its feasibility by testing it on an Android based testbed and evaluate its performance and scalability using simulations.…”