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Broadband Fixed Wireless Access:
Point-to-Multipoint vs Mesh Networks

At the recent Expocom exhibition in Paris, Baptiste Essevaz-Roulet, a consultant at ATDI, read a paper comparing point-to-multipoint networks with mesh networks as part of the «Network Deployment» conference.

• Point-to-multipoint systems, like LMDS, allow connecting subscribers (CPE) to a network of base stations (BS). These systems have proven their technological reliability but face financial difficulties.
• The Mesh technologies, also described as multipoint-to-multipoint, are quite new systems. No base station is required, as all the subscribers are connected together as long as they are in direct line of sight. The interconnection relies on IP protocols. Mesh technology is commonly presented as more cost effective than LMDS, through lower cost to launch the network and more flexibility when deploying it.

Each technology implies deployment constraints that have direct consequences on the operators’ business plan, in terms of investments, time to reach the break-even, risks, and profit.

Point-to-multipoint networks require the installation of a minimum of Base Stations before the roll out of services to the first customers. Hence, the initial investments are higher, as base stations are expensive. When the network is created the incoming costs are very low: the only costs correspond to the subscriber’s connection. On the deployment point of view, a long preliminary study phase is needed to identify and negotiate the sites where the BS will be installed.

On the other hand, the cost of a Mesh CPE is higher, but no expensive BS is needed. The initial investment is lower, but the cost of the network is therefore increasing with time. The deployment phase seems to be simpler as no special site is needed, and more flexibility should be provided. However, a minimum of repeaters is mandatory to start the network. The question of spectrum efficiency, which can be highly expensive, can also be raised.

Through simulation of different types of networks, typical deployment strategies can be analyzed. Various factors must be taken into account (e.g. terrain topology, type of town targeted, subscribers’ density and arrival in time, equipment chosen) to create different scenarios and compare them in order to make decisions and eventually, choose the best solution.

ATDI with its network-planning tool ICS Telecom can simulate different types of networks with typical deployment strategies. Depending on the type of town targeted, the subscriber density and arrival in time, the equipment chosen, different scenarios can be analyzed and compared in order to make decisions and eventually, choose between LMDS and Mesh network technologies.