| Aeronautical Telecommunication Network: medium access and network control{dollar}sp1{dollar}(ATN) is a proposed global telecommunication network for the airlines integrating the various ground subnets and providing a standardized interface to any network. It involves defining several aspects of the network such as air interface (medium access protocols, logical link control), network issues (routing, fading, QOS requirements) and mobility management (access channel selections, system access, handover and roaming).; Currently, airlines use a character oriented messaging system called ACARS (Aircraft Communication and Reporting System) on the VHF channel or SATCOM (Satellite Communication). The new ATN network will be faster and more efficient than ACARS and upward compatible with it. The goal of the ATN is to achieve data transparency and bit oriented messaging, interoperability of systems and functions, better addressing, data rates and reduced life cycle costs.; The air interface is between aircraft and base station. Efficient MAC would ensure better utilization of the very limited bandwidth available. These protocols must integrate voice and data communications. We look at several studies conducted on candidates such as CSMA and DRMA. Then an improved algorithm that can increase the throughput of DRMA is evaluated. The algorithm is also compared against a modified Cellular Digital Packet Data (CDPD) protocol.; We also look into handoff mechanism for this protocol and a solution to avoid front-end clipping. Handoffs are necessary to maintain a seamless contact with the airplanes. We evaluate a scheme called Time Division Tasselation, which allows a single frequency to be used across multiple ground stations.; Due to the common medium of access, limited bandwidth and noisy channels congestion control is critical to maintain operability of the system. As a mechanism for congestion prevention, we consider logical link control. Specifically, evaluate the effect of logical link control over the channel access protocols: CSMA and DRMA.; The simulations have been carried out on OPNET and Maisie. The models and the benefits of using the simulation environments are discussed. ftn{dollar}sp1{dollar}This work was carried out under the MICRO project 94-048 at UCLA and sponsored by Teledyne Controls. Aeronautical Telecommunication Network (ATN): Design and Performance. |
