Keizo Sugiyama

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This paper presents novel broadcast methods for an inter-vehicle communications system for ITS. During inter-vehicle communications, it is essential that emergency information be broadcast to surrounding vehicles. Emergency information such as emergency-vehicle-approach information and traffic accident information are needed by vehicles in a particular(More)
This paper presents a prediction of the trend in radio resource availability in cognitive radio. In this paper, cognitive radio is defined as the wireless communication technology in which each node communicates via an optimal wireless system based on recognition of the radio resource availability in heterogeneous wireless communication systems. We focused(More)
This paper proposes a multihop mobile communications system using an MC-CDMA transmission technique in the forward links. In the system, it is assumed henceforth that each mobile station has a relaying function where a frequency band is used both in the 1st and 2nd hops. Then, we examined a radio resource allocation method in the forward links. In this(More)