On the Feasibility of the Link Abstraction in Wireless Mesh Networks

Outdoor community mesh networks based on IEEE 802.11 have seen tremendous growth in the recent past. The current understanding is that wireless link performance in these settings is inherently unpredictable, due to multipath delay spread. Consequently, researchers have focused on developing intelligent routing techniques to achieve the best possible performance. In this paper, we are specifically interested in mesh networks in rural locations. We first present detailed measurements to show that the PHY layer in these settings is indeed stable and predictable. There is a strong correlation between the error rate and the received signal strength. We show that interference, and not multipath fading, is the primary cause of unpredictable performance. This is in sharp contrast with current widespread knowledge from prior studies. Furthermore, we corroborate our view with a fresh analysis of data presented in these prior studies. While our initial measurements focus on 802.11b, we then use two different PRY technologies as well, operating in the 2.4-GHz ISM band: 802.11g and 802.15.4. These show similar results too. Based on our results, we argue that outdoor rural mesh networks can indeed be built with the link abstraction being valid. This has several design implications, including at the MAC and routing layers, and opens up a fresh perspective on a wide range of technical issues in this domain

Censor Networks: A Critique of “Sensor Networks” from a Systems Perspective

This writeup presents a critique of the field of “Wireless Sensor Networks (WSNs)”. Literature in this domain falls into two main, distinct categories: (1) algorithms or protocols, and (2) applicationcentric system design. A striking observation is that references across these two categories are minimal, and superficial at best. We argue that this is not accidental, and is the result of three main flaws in the former category of work. Going forward, an applicationdriven, bottom-up approach is required for meaningful articulation and subsequent solution of any networking issues in WSNs

Communication using multiple wireless interfaces”,

Abstract-With the emergence of different wireless technologies, a mobile terminal equipped with multiple interfaces can achieve a much higher bandwidth by aggregating the bandwidth offered by the individual networks. In this paper, we present a system based on Mobile IP that achieves the above objective. We will discuss in detail the architectural requirements and algorithms that are needed to support the above system