In this paper, a new handover technique for OFDM-based mobile mesh networks (MMNs) is proposed to reduce the handover overhead by distinguishing an inter-cluster handover event from an intra-cluster handover event using a hierarchical design concept of a preamble. The proposed handover procedure can simplify scanning procedure and skip/simplify network entry procedure, resulting in a significant reduction of handover overhead.

Random multiple access and reservation multiple-access protocols which are currently employed in most satellite communication systems have some merits and demerits according to the type of users and traffic. A modified packet demand assignment multiple access (PDAMA) protocol with better characteristics is proposed and analyzed. Using simulation with approximate analysis, the performance of the modified PDAMA is compared with that of a modified random-access protocol as well as the original PDAMA in terms of delay and throughput. For small packet arrival rate, the performance of the proposed access protocol is shown to be similar to that of the modified random-access protocol, and better than that of the PDAMA protocol. While the packet arrival rate increases, the performance of the proposed access protocol is improved greatly compared with that of the PDAMA protocol.>