In Carmesh, we are considering urban wireless mesh networks (WMNs) as one option for vehicular connectivity. This kind of network has emerged as a highly flexible, reliable and cost efficient solution for wirelessly covering large areas. It provides low-cost Internet access through multihop communications.
The WMN architecture components are gateways, mesh routers and mesh clients. The gateway serves as a bridge between the wireless network nodes and the Internet. Mesh routers form a wireless backhaul to provide multihop wireless Internet connectivity to the mesh clients. They are designed to provide two functionalities: (1) act as Access Points (APs) to provide internet connectivity to the end-users, and (2) operate as relays to forward packets in a multihop fashion from neighbor mesh routers to the Internet gateway and vice versa. Mesh clients are simply the end-users when they do not operate as relay to forward traffic from neighbouring nodes. They can be the source/destination of connections and are sometimes mobile; in carmesh they are typically vehicular.
From this description, such a network can be represented as a two-tier mesh network, consisting of a backhaul tier (mesh router to mesh router) and an access tier (mesh router to end-users). Both tiers are built on either the same or different wireless access technologies. A schematic example of this description is shown in the figure below.
While the general architecture is straightforward to comprehend, realizing WMNs that perform well is a non-trivial problem – WMN design is very challenging. Design of WMNs starts with network deployment which encompasses issues ranging from (data) traffic estimation to radio planning. In the next post, we will look at some approaches to deployment of WMNs.