Abstract: A road antenna apparatus includes a road antenna 104 which is mounted on a post 103 and at an elevated position on a road R and establishes radio communication with an on-vehicle radio device 102 mounted in a vehicle 101 which is traveling over the road; and a laser-beam emitting device 111 which is mounted on the road antenna and radiates a laser beam onto a predetermined position 113 on the surface of the road. An offset in the angle at which a road antenna is mounted can be readily ascertained on the basis of a distance between a predetermined position on the surface of the road and a position 114 on the road surface onto which a laser beam is actually radiated.

Abstract: A road antenna apparatus includes a road antenna 104 which is mounted on a post 103 and at an elevated position on a road R and establishes radio communication with an on-vehicle radio device 102 mounted in a vehicle 101 which is traveling over the road; and a laser-beam emitting device 111 which is mounted on the road antenna and radiates a laser beam onto a predetermined position 113 on the surface of the road. An offset in the angle at which a road antenna is mounted can be readily ascertained on the basis of a distance between a predetermined position on the surface of the road and a position 114 on the road surface onto which a laser beam is actually radiated.

Abstract: A road antenna apparatus includes a road antenna 104 which is mounted on a post 103 and at an elevated position on a road R and establishes radio communication with an on-vehicle radio device 102 mounted in a vehicle 101 which is traveling over the road; and a laser-beam emitting device 111 which is mounted on the road antenna and radiates a laser beam onto a predetermined position 113 on the surface of the road. An offset in the angle at which a road antenna is mounted can be readily ascertained on the basis of a distance between a predetermined position on the surface of the road and a position 114 on the road surface onto which a laser beam is actually radiated.

Abstract: A microcellular communication system which broadcasts its local channel block, including the control channels allotted from a total channel block to the microcellular system, on all control channels being used by the system. A mobile unit seeking access to the microcellular system initially searches the total channel block in an effort to receive the local channel block information broadcast by the microcellular system. The mobile unit compares received local channel block information with stored total channel block information and replaces its memory content with the newly received information. Periodic searching of stored channel block information is conducted to verify that the mobile unit has the relevant channel block information for the local microcellular system.

Abstract: In a micro cellular system (MCS) which co-exists with a cellular system (CMTS) in a frequency band, fraudulent use of the MCS when it is moved from the CMTS to the location of another CMTS is prevented by providing a control unit 2 in the MCS which controls the overall operation of the MCS and a system ID receiving and judging unit which is capable of receiving all the downward control channels used in the CMTS. When the system ID receiving and judging unit receives a system ID transmitted from the CMTS which matches a system ID stored in the MTS, the control unit is allowed to start the operations of the MCS. Otherwise, the MCS is disabled. Therefore, if the MCS moves to another CMTS zone where the system ID is different, it is impossible to operate the MCS.

Abstract: A microcellular communication system which broadcasts its local channel block, comprising the control channels allotted from a total channel block to the microcellular system, on all control channels being used by the said system. A mobile unit seeking access to the microcellular system initially searches the total channel block in an effort to receive the local channel block information broadcast by the microcellular system. The mobile unit compares received local channel block information with stored total channel block information and replaces its memory content with the newly received information. Periodic searching of stored channel block information is conducted to verify that the mobile unit has the relevant channel block information for the local microcellular system.

Abstract: A portable radio telephone equipment in which both the frequency and equipment can be used in common to CMTS and MCS so that the efficiency for use both for the frequency and equipment can be improved. This equipment monitors the control channel number of CMTS through a radio transmission section and a control section for common use to CMTS and MCS and answers a call from a base station or performs transmission. On the other hand, this equipment selectively receives the control channel number of MCS and answers a call from a base station or performs transmission. Either one of these actions is automatically selected on the basis of the reception level and system ID of the control channel number. At this time, standby-state reception is performed on the judgment as to which one of CMTS and MCS is to be accessed, by automatically detecting the positional condition of the equipment in use.

Abstract: In a microcellular system operated in the same frequency band as a cellular system, an interference-free channel is automatically searched and allocated. The microcellular system which shares the frequency band with the cellular system comprises a control unit, a base station and a multi-channel selecting receiver. The multi-channel selecting receiver monitors a use status of cellular channels of the band by repetitively scanning voice channels for a scanning time period substantially longer than the duration of any single voice communication to detect idling channels and allocates them to its own system. Whenever a communication request is issued, the base station detect a channel not used by its own system from the idling channels and allocates it for communication.

Abstract: A method and system for preventing fraudulent use in a cellular system whereby upon establishment of communication with said micro cellular system, a maintenance console transmits an identifier to the control unit of said micro cellular system. The control unit compares the transmitted identifier to a stored value and controls the operation of the micro cellular system based upon said comparison. Operations of the micro cellular system are terminated if said transmitted value does not match said stored value and maintained if a match is found. The control unit additionally includes a time limit timer which is set upon activation of the control unit and is adapted to be reset upon command from the maintenance console, which command accompanies each communication for which access is maintained. Operation of the micro cellular system is terminated when said time limit expires without resetting.

Abstract: In a microcellular system operated in the same frequency band as a cellular system, an interference-free channel is automatically searched and allocated. The microcellular system which shares the frequency band with the cellular system comprises a control unit, a base station and a multi-channel selecting receiver. The multi-channel selecting receiver monitors a use status of cellular channels of the band to detect idling channels and allocates them to its own system. Whenever a communication request is issued, the base station detects a channel not used by its own system from the idling channels and allocates it for communication.