Extended Topology Knowledge for Localization and Quality of Service with OLSR

Mobile ad-hoc networks (MANETs) are infrastructure-less networks where network topology changes very frequently and routing is not a trivial task. OLSR is a link-state routing algorithm that is optimized to reduce the communication overhead by reducing the amount of topology information that is continuously advertised. This optimization constrains OLSR to partial network topology knowledge which is the only input used along with the Minimum Hop Count (MHC) metric to construct routing paths. Therefore, OLSR suffers from a lack of knowledge, such as full topology knowledge, nodes and links status (e.g. remaining battery, link quality) and network load in order to make better routing decisions. However, OLSR allows manipulating the amount of advertised topology information. This research explores mechanisms to extend the topology knowledge with the objectives of: 1) fully understanding the possible trade-offs between achievable topology knowledge and communication overhead and, 2) providing support for localization and Quality of Service (QoS). Several TC_Redundancy [7] strategies are combined with the MPR_Coverage feature [7] of OLSR while maintaining its optimal broadcasting mechanism. NS-2 simulation results show the costs and benefits of increasing the topology knowledge to make OLSR a supportive routing protocol for localization and QoS. A possible NS-2 bug is also discussed. Statistical analysis is applied to eliminate any effect that this bug may have had