Mobile station communication device, inter-mobile station communication system, and inter-mobile station communication method

#The embodiments discussed herein are related to a mobile station communication device, an inter-mobile station communication system, and an inter-mobile station communication method for a mobile station to perform wireless communication with another mobile station.

#The automobile society of today has many serious problems such as traffic congestion. To solve such problems, ITS (Intelligent Transport System) has been proposed, and specific systems such as VICS (Vehicle Information Communications System) and ETC (Electronic Toll Collection System) have been put into practice.

#Furthermore, in recent years, as a system relevant to ITS, an inter-vehicle communication system is attracting attention for the purpose achieving a safe automobile society. An inter-vehicle communication system is used for performing wireless communication between vehicles. An inter-vehicle communication system is different from a mobile wireless communication system in which a base station implements centralized control on mobile terminals such as mobile telephones. Specifically, in an inter-vehicle communication system, decentralized autonomous control is implemented so that the respective vehicles perform communication with each other in accordance with a certain rule. That is to say, ad hoc communication is performed. Generally, the CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) method is known as an example of a decentralized autonomous control system, and the CSMA/CA method is proposed as an inter-vehicle communication system.

#FIG. 1 is a schematic diagram of an inter-vehicle communication system according to an embodiment of an inter-mobile station communication system;

#FIG. 2 schematically illustrates a configuration of an inter-vehicle communication device installed in each vehicle, used in the inter-vehicle communication system of FIG. 1;

#FIG. 3 illustrates a configuration of a transmission resource setting unit of the inter-vehicle communication device of FIG. 2;

#A mobile station communication device, an inter-mobile station communication system, and an inter-mobile station communication method according to preferred embodiments of the present invention will be explained with reference to accompanying drawings. FIG. 1 is a schematic diagram of an inter-vehicle communication system 10 corresponding to an inter-mobile station communication system according to an embodiment of the present invention. In the following description, a vehicle equipped with a communication device for performing wireless communication with another vehicle is given as an example of a mobile station. The mobile station is not limited to a vehicle that performs wireless communication with another vehicle; the mobile station may be various communication devices that move along a road.

#Overview of Inter-Vehicle Communication System

#The inter-vehicle communication system 10 includes plural assignment areas corresponding to different positions along a road, and assigns different transmission resources to the respective assignment areas. When a vehicle is located at a particular assignment area, the inter-vehicle communication device installed in the vehicle performs transmission with the use of the transmission resource assigned to the particular assignment area. A road may be a road extending between intersections. That is to say, there may be plural assignment areas provided along a road extending between intersections. As illustrated in FIG. 1, a vehicle a located at an assignment area at a position A on a linear road uses a transmission resource Ra to perform transmission, a vehicle b located at an assignment area at a position B uses a transmission resource Rb to perform transmission, and a vehicle c receives the transmission data from the vehicle a and the vehicle b. In this case, the vehicles a and b use different transmission resources, and therefore the two sets of transmission data are received at the vehicle c without colliding into each other. That is to say, the hidden terminal problem does not occur. In FIG. 1, d indicates the distance set for transmitting and receiving data in communication performed between the receiving position and the positions A and B. This distance d is the communication distance specified for preventing vehicles from colliding into each other. Communication can be performed between the vehicles a and b and the vehicle c, which are separated by this transmission/reception distance d. As a matter of course, communication can be performed even if the distance is shorter than the transmission/reception distance d. The transmission/reception distance d is, for example, 80 m.