A Markovian Model for Analyzing Opportunistic Request Routing in Wireless Cache Networks

Abstract

In this paper, we investigate the request routing delay of opportunistic routing for cache-enabled wireless networks considering uncorrelated and temporally correlated wireless channels. We model wireless channel variation at different time scales via two approaches: an abstract modeling approach where we model the variation considering Rayleigh fading and shadowing channel models and an empirical approach where the variation is modeled directly using signal strength measurements. We develop Markovian models to analyze the performance of opportunistic forwarding, leverage the wireless channel models to determine the packet transmission success probabilities and then utilize them to obtain the request routing delay. We first perform numerical experiments and simulations considering Rayleigh fading and shadowing channel models and then conduct a trace-based evaluation using signal strength measurements collected over a wireless sensor network testbed. Our experiments demonstrate the validity and effectiveness of our Markovian model in determining the request routing delay in real-world settings. Our work takes a step forward in providing network operators a tool for analyzing network performance before deploying their networks.