Wireless Mesh Networks/Introduction

 Wireless Mesh Networks 

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Acknowledgements — Introduction — Mesh network basics — History Highlights — Motivation — Economics — Politics — Social Impact — Regulatory — Taxonomy of Mesh Types — Design Parameters — How many radios? — Transport — Access — RF concerns — What layers does it run on? — Topology Control — Mobility Handoffs — Applications — Content — Operations — Accounting and Billing — Management — Getting Power to the Node — Survey Tools — Planning Tools — Mounting Options — Testing Tools — Meshes you can build — Conclusion — Applicable Standards — Known Deployments — Mesh Timeline — Mesh Network Vendors — Bibliography — Glossary — Index

Introduction

Wireless networks nowadays are part of our everyday life, as witnessed by several features: the number of cell (mobile) phone subscriptions reached 7.3 billion in 2014., short-range radio technologies such as WiFi and Blue-tooth are widespread as well as radio frequency IDs (RFIDs).

In a search on Google for “next generation wireless network,” top hits mostly refer to evolutions of the cellular technology collectively named 4G, including technologies such as LTE (Long-Term Evolution), LTE Advanced, etc. These technologies are essentially aimed at improving quality of service (QoS) in cellular networks, especially that which concerns data services, which are expected to play an increasing role in connected world. The improvements are mostly obtained through advancements in the physical and medium access layer of the network protocol stack, for example, through extensive use of multi antenna systems, while the overall architecture of the cellular network is mostly unchanged. Thus, forthcoming 4G networks can be considered as an evolution of the well-established cellular network concept.

On the other hand, the class of networks (ad hoc networks, mesh networks, wireless sensor networks, vehicular networks, and opportunistic networks) that we collectively call next generation wireless networks are characterized by very different features compared to cellular networks:

• Cellular networks rely heavily on a wired, very expensive communication infrastructure – the network of cellular base stations – to perform communication; on the contrary, next generation wireless networks are characterized by a lightweight – or even absent – infrastructure.
• Cellular networks are based on the use of relatively long wireless links,with typical communication ranges in the order of up to a few kilometers; on the contrary, next generation wireless networks use short-range – in the order of a few tenths of meters, or hundreds of meters at most – wireless links.
• Cellular networks rely heavily on the presence of several centralization points, where servers are used for optimizing resource allocation and coordinate radio channel access between the different users in a cell and in adjacent cells; on the contrary, in next generation wireless networks, centralization points are typically lacking, and most network functionalities must be realized in a fully distributed, self-coordinated environment.
• Cellular networks are single-hop wireless networks, since a mobile terminal directly communicates with a base station in the vicinity; on the contrary, next generation wireless networks typically make extensive use of multi-hop communications to compensate for the short radio range and increase coverage.

Header text	Cellular network	Wireless mesh network
Infrastructure	Yes	No, lightweight
Radio range	≤ 2km	≤ 300m
Centralization points	Yes	Mostly no
Type of communication	Single-hop	Multi-hop
Radio channel access	Coordinated	Mostly uncoordinated

It is then evident that the class of emerging short-range wireless networks mentioned above displays striking differences with respect to traditional cellular networks, and that the design and realization of a network of this class entails defining brand-new network architectures and networking solutions spanning the entire network protocol stack. This explains our choice of naming the emergent class of short-range, multi-hop, decentralized wireless networks “next generation wireless networks.” Unless stated otherwise, in the remainder of this Wikibook we will use the term next generation wireless network exclusively to refer to a member of the class of short-range, multi-hop,decentralized wireless networks

What it is actually ?

Wireless mesh network is a multi-hop, peer-to-peer wireless network in which mesh nodes connect with redundant interconnections and cooperate with one another to route packets inside the network.

Mesh nodes are small radio transmitters that function in the same way as a wireless router. Nodes use the common WiFi standards known as 802.11a, b and g to communicate wirelessly with other nodes.

Nodes are programmed with algorithms that tells them how to interact within the mesh network. The packets that carries informations travels across the network from point A to point B by hopping wirelessly from one mesh node to the next. The nodes automatically choose the quickest and safest path in a process known as dynamic routing. . There are two types of mesh network which are partial mesh and also full mesh. Partial mesh is mesh where not all the nodes are connected to each other meanwhile the full mesh is mesh where all the nodes are connected to each other

References

1. USENIX 2003 Annual Technical Conference, FREENIX Track — Paper "Building a Wireless Community Network in the Netherlands"
2. "The innovation journey of wifi" authors Wolter Lemstra, Vic Hayes, John Groenewegen, Technische Universiteit Delft, The Netherlands Cambridge University Press 2010 ISBN:9780521199711