Multipurpose Ais Networking Protocol Study

The communication system based on self-organizing TDMA (hereinafter as SOTDMA) technology, enables the self-networking by pre-appointing time slots among the network members in case of no supporting network-centric station, and it is applicable to co-site and multi-access networking modes. It is the major feature that such networking has no limitation to area and is good in applicability and economical efficiency, so it is widely used in both military and commercial identification and navigation fields. SOTDMA protocol is the core for self networking, and SOTDMA consists of a set of complex time-slot preappointment algorithm and message development mechanism. It is critical and difficult to study SOTDMA protocol and apply it flexibly to develop Multi-Automatic Identification System (hereinafter as MAIS).MAIS equipment has two sets of independent networking channels, i.e., AIS channel and dedicated channel, both apply self-networking modes. The paper proposes a practical solution of AIS-channel and dedicated-channel networking protocols based on the practice for development of MAIS, and by studying SOTDMA protocol. The networking protocol is eventually implemented in software.This thesis describes the background of MAIS development and use value at first, and then gives general introduction of the composition and operating principle to MAIS equipment, to support the protocol implementation environment description. Followed is the introduction of AIS-channel networking protocol design for MAIS with details and analysis on time-slot allocation algorithm, message architecture, and net-entry process subject to SOTDMA protocol. And then design of dedicated-channel networking protocol is described on the above basis and per the major technical features and implemented functions of the dedicated channel. The focus is on reallocation of dedicated-channel time slots; adjustment of related parameters in SOTDMA protocol; change of net-entry process and message transmitted via dedicated channel, based on AIS-channel networking protocol architecture. And finally, there is analysis on dedicated-channel time-slot conflict probability by way of simulation to verify the dedicated-channel networking workably.The author is in charge of design of AIS-channel and dedicated-channel networking protocols and external interface data exchange protocol for MAIS project. It is nearly 2 years since the project approval in 2008; the MAIS is now in trial service, with various technical specifications up to design requirements. It is hopeful to be equipped to our Navy's convoy fleet to Somalia upon completion of trial period.