Performance analysis of the AODV ad hoc routing protocol in a dual radio network

Abstract

Existing ad hoc routing protocols supports multiple radio interfaces, but they are designed for radio interfaces with similar properties. In contrast, in a typical usage scenario the interfaces will have different properties. There will be a need for longer range resulting in a lower bandwidth, while some applications will have higher capacity requirements but for nodes in close proximity. A solution may be to use one interface with low bandwidth and long range for example in the UHF band, whilst the other interface has a higher bandwidth and shorter range in the VHF or SHF band. Such a solution will not be energy efficient, so it will be feasible only for vehicle-mounted radios like in tactical military or emergency service networks. With the shortest path routing, the long range interfaces tend to be selected. The traffic is therefore shifted towards the links with the lowest capacity. Firstly, we analyze and illustrate the problem for the typical reactive routing protocol, AODV. Secondly, we propose two techniques that take the underlying radio capacity into account when a new route is established. Compared to original AODV, the proposed algorithms provide higher network throughput, less routing overhead, less end-to-end delay and still provides connectivity. The applicability to this approach is one of practical interest to scenarios where nodes are typically unevenly distributed; a network where some nodes only are reachable over long range radios, while others are also reachable over short range high capacity radios.