MOBILE COMMUNICATION SYSTEM

• US 3,714,574 A
• Filed: 04/25/1969
• Issued: 01/30/1973
• Est. Priority Date: 04/30/1968
• Status: Expired due to Term

• Current Assignee: Fumio Suzuki, Koichi Osada, Takesi Baba, Takuya Hokawa
• Original Assignee: Fumio Suzuki, Koichi Osada, Takesi Baba, Takuya Hokawa
• Inventors: Baba, Takesi, Hokawa, Takuya, Suzuki, Fumio, Osada, Koichi
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Orsino, Jr., Joseph A.
• Application Number:
  US04/819,376
• Time in Patent Office: 1,376 Days
• Field of Search: 325/51,53,54,56,57 343/177
• US Class Current: 455/436
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04W 36/20 for optimising the interference level

Abstract

A mobile communication system in which many base stations are disposed along the path of a moving body and are successively switched over as the moving body moves along its path, and a plurality of zones ahead and after the zone through which the moving body is passing are blocked against the radio frequency used by the moving body so as to ensure a minimum talking time. In the system, when two moving bodies during oral communication at the same radio frequency approach each other, the radio frequency used by one of the moving bodies is altered to another frequency and the number of blocked zones is varied depending on the advancing direction of the moving body so as to improve the utility of the radio frequency.

Claims

1. A mobile communication system including a fixed station, a multiplicity of fixed radio stations belonging to said fixed station and having a transmitter and a receiver for a plurality of radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for a plurality of radio frequencies, and means for switching over one of said fixed radio stations to another under control of said fixed station when a mobile station during oral communication moves into one zone from another, characterized in that, when two mobile stations under oral communication at the same radio frequency approach each other, said fixed station issues an instruction to one of the two mobile stations to alter the radio frequency employed by said mobile station and to alter also the radio frequency employed by the corresponding fixed radio station.

2. A mobile communication system including a fixed station, a multiplicity of fixed radio stations belonging to said fixed station and having a transmitter and a receiver for a plurality of radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for a plurality of radio frequencies, and means for switching over one of said fixed radio stations to another under control oF said fixed station when a mobile station under oral communication moves into one zone from another, characterized in that, when two mobile stations during oral communication at the same radio frequency approach each other, said fixed station checks for the presence of an alterable idle and available radio frequency in the zones of both the fixed radio stations through which the mobile stations are passing, and issues an instruction to the mobile station passing through the zone of either fixed radio station in which there is an idle and available radio frequency and to alter also the radio frequency employed by the said fixed radio station.

3. A mobile communication system including a fixed station, a multiplicity of fixed radio stations belonging to said fixed station and having a transmitter and a receiver for a plurality of radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for a plurality of radio frequencies, and means for switching over one of said fixed radio stations to another under control of said fixed station when a mobile station during oral communication moves into one zone from another, characterized in that, when two mobile stations under oral communication at the same radio frequency approach each other, said fixed station selects a radio frequency and sends out a signal indicating the radio frequency number under oral communication relative to the selected radio frequency thereby to instruct one of the mobile stations to alter the radio frequency employed by said mobile station.

4. A mobile communication system including a fixed station, a multiplicity of fixed radio stations belonging to said fixed station and having a transmitter and a receiver for a plurality of radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for a plurality of radio frequencies, and means for switching over one of said fixed radio stations to another under control of said fixed station when a mobile station during oral communication moves into one zone from another, characterized in that, when two mobile stations during oral communication at the same radio frequency approach each other, said fixed station selects a radio frequency and sends out a signal indicating the selected radio frequency number relative to the radio frequency employed for oral communication thereby to instruct one of the mobile stations to alter the radio frequency employed by said mobile station.

5. A mobile communication system including a fixed station, a multiplicity of fixed radio stations belonging to said fixed station and having a transmitter and a receiver for a plurality of radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for a plurality of radio frequencies, means for blocking one or more zones on each side of the zone of a fixed radio station through which zone a mobile station is moving during oral communication, and means for switching over said fixed radio station to another under control of said fixed station when said mobile station during oral communication moves from said zone into another, wherein when two mobile stations during oral communication at the same radio frequency approach each other, said fixed station issues an instruction to one of the two mobile stations to alter the radio frequency employed by said mobile station and to alter also the radio frequency employed by the corresponding fixed radio station, characterized in that said mobile station waits until there appears an idle and available radio frequency when such idle and available radio frequency does not exist in any one of the zones of the fixed radio stations through which zones the mobile stations are approaching each other, and the distance through which said mobile station moves during a maximum allowable waiting time is taken into account in blocking the zones.

6. A mobile communication system including a fixed station, a multiplicity of fixed radio stations belonging to said fixed station And having a transmitter and a receiver for a plurality of radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for a plurality of radio frequencies, means for blocking one or more zones on each side of the zone of a fixed radio station through which a mobile station is moving during oral communication, and means for switching over said fixed radio station to another under control of said fixed station when said mobile station during oral communication moves from said zone into another, wherein when two mobile stations during oral communication at the same radio frequency approach each other, said fixed station issues an instruction to one of the two mobile stations to alter the radio frequency employed by said mobile station and to alter also the radio frequency employed by the corresponding fixed radio station, characterized in that the number of blocked zones is varied depending on the direction of movement of said mobile station in blocking the zones.

7. A mobile communication system comprising a fixed station, a multiplicity of fixed radio stations associated with said fixed station, each of said fixed radio stations defining a communication zone and having a transmitter and a receiver for the same plural radio frequencies such that each communication zone utilizes the same plural radio frequencies, a multiplicity of mobile stations having a transmitter and a receiver for said plural radio frequencies, means for switching over one of said fixed radio stations to another under control of said fixed station when a mobile station during oral communication moves into one zone from another, said fixed station including means responsive to two mobile stations under oral communication at the same one of said plural radio frequencies while approaching each other for preventing communication interference between the two mobile stations, said interference preventing means including means for instructing one of the mobile stations to alter the radio frequency employed thereby to a different one of said plural radio frequencies and for altering the radio frequency employed by the fixed radio station for the one mobile station to the same different radio frequency, whereby the other mobile station continues to employ said same one radio frequency.

8. A mobile communication system as defined in claim 7, wherein said fixed station includes means for determining the presence of an alterable idle and available radio frequency in the zones of both the fixed radio stations through which the mobile stations are passing and for instructing one of the mobile stations to alter the radio frequency employed thereby in accordance with the available and idle radio frequency.

9. A mobile communication system as defined in claim 8, wherein said fixed station includes means for blocking one or more zones on each side of the zone of a fixed radio station through which a mobile station is passing during oral communication at one of said plural radio frequencies for preventing the other of said mobile stations to employ said one frequency in said blocked zones.