Masayoshi Moriya

Quality analysis of CSMA/CA communications in inter-vehicle communication services

Recently, inter-vehicle communication services which support safe driving have been attracting significant. CSMA/CA is a representative communication method in inter-vehicle communications. It is necessary to clarify the quality characteristics of inter-vehicle communication in order to achieve driving support. Although there are conventional models for CSMA/CA which are derived using an ideal environment, they are not consistent with behavior in actual inter-vehicle communication. This paper proposes a mathematical model that can analyze communication quality between the specific vehicles by dealing with the discrepancies between conventional theory and practice. Furthermore, we analyze communication performance between vehicles in specific accidents using the proposed model.

Low-cost gigabit PCF transceivers using commercially available logic ICs for short-range optical networks

We propose low-cost gigabit optical transceivers for broadband and short-range communication networks using plastic clad optical fiber. The transceivers can be used for broadband home and intravehicle local area networks based on optical IEEE1394, large-throughput optical interconnection, digital visual interfaces, and so on. We have fabricated a 500Mbit/s or a 1.25Gbit/s low-cost optical transceiver with a proposed simple circuit configuration. Simple assembly technologies have also been improved for mounting to reduce assembly cost. The total cost of the fabricated optical transceiver can be reduced to less than 2/3 compared with the cost of a conventional transceiver.