In OLSR, only selected multipoint relays (MPRs) are allowed to forward broadcast data during the flooding process, which reduces the message propagation overhead compared to the classical flooding mechanism. Since every node in a network selects its own MPRs independently, many nodes may be MPRs of other nodes, which results in many collisions in the medium access control (MAC) layer under heavy traffic conditions. In this paper, we propose an MPR candidate selection mechanism for broadcast data aggregation in mobile ad-hoc networks. The proposed MPR candidate selection scheme can reduce the number of MPR candidates and appropriately spread MPR candidates over the whole network area. The performance of the proposed MPR candidate selection mechanism is investigated via mathematical analysis and simulations. We also propose a broadcast data aggregation mechanism to achive efficient resource utilization. Performance evaluation indicates that the proposed MPR candidate selection and broadcast data aggregation mechanism is efficient under heavy broadcast traffic load conditions.

The dynamic channel selection mechanism used in existing multi-channel MAC protocols selects an idle data channel based on channel usage information from one-hop neighbor nodes. However, this method can cause multi-channel hidden node problem in multi-hop wireless networks. This letter proposes a new approach to channel selection. Nodes snoop data channels during idle times and then select an idle data channel within the carrier sensing range using both the snooping results and the channel usage information. Our simulation results verify that the proposed channel selection approach can effectively avoid the multi-channel hidden node problem and improve the networkwide performance.