Opportunistic Data Collection in Sparse Wireless Sensor Networks

Opportunistic wireless sensor networks (WSNs) have recently been proposed as solutions for many remote monitoring problems. Many such problems, including environmental monitoring, involve large deployment scenarios with lower-than-average node density, as well as a long time scale and limited budgets. Traditional approaches designed for conventional situations, and thus not optimized for these scenarios, entail unnecessary complexity and larger costs. This paper discusses the issues related with the design and test of opportunistic architectures, and presents one possible solution&#8212;CHARON (Convergent Hybrid-replication Approach to Routing in Opportunistic Networks). Both algorithm-specific and comparative simulation results are presented, as well as real-world tests using a reference implementation. A comprehensive experimental setup was also used to seek a full characterization of the devised opportunistic approach including the derivation of a simple analytical model that is able to accurately predict the opportunistic message delivery performance in the used test bed.</p

Experimental and Analytical Performance Evaluation of a Real Opportunistic Wireless Sensor Network

Abstract: The use of opportunistic communications, while increasing in popularity, is still limited, due in part to some uncertainty that still exists regarding its performance in real-world conditions. This paper tries to assess the real performance of an opportunistic routing implementation in a physical setting, by comparing i

Measuring TCP over wifi: A real case

Abstract — We present a measurement study of an operative WLAN. After briefly presenting the methodology used to generate traffic and measure performance indices, we present results focusing on the performance perceived by TCP connections, to understand the mechanisms which have a major effect on performance. We investigate the impact of TCP parameters, like the maximum congestion window, the effectiveness of link layer mechanisms such as RTS/CTS, and multirate transmissions. Rather than only presenting aggregate measures, we show results relative to individual TCP connections, considering throughput as well as TCP round trip time, congestion window and segment retransmissions. I