Mobile communication for a mobile station near or outside a service area of a base station

• US 5,850,593 A
• Filed: 07/13/1995
• Issued: 12/15/1998
• Est. Priority Date: 07/13/1994
• Status: Expired due to Term

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Uratani, Chikara
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US08/502,252
• Time in Patent Office: 1,251 Days
• Field of Search: 455/7, 455/9, 455/11.1, 455/15, 455/18, 455/33.1, 455/54.1, 455/54.2, 455/56.1, 455/67.1, 455/422, 455/517, 455/524, 455/525, 370/293, 370/315, 370/321, 370/326, 370/327
• US Class Current: 455/11.1
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a mobile communication network comprising a base station (11) having a service area (13) and a plurality of mobile stations, communication is rendered possible between the base station, with a first station (15(1)) in the service area used as a repeater station, and a second station (15(2)) which may be present near or beyond a boundary of the service area. It is presumed that the mobile stations are operable with battery saving and that such a repeater station exists in a communication area (17) of the second station put into full operation. Preferably, the mobile communication network is operable with time division multiplexing, with each frame composed of a predetermined number of time slots.

Claims

1. A communication method in a mobile communication system having a base station with a service area, a first mobile station in the service area and a second mobile station located near or beyond a boundary of the service area, comprising the steps of:

transmitting from said base station a first communication signal containing a first information signal;

when first data is received from said base station at said first mobile station, moving said first communication signal received in a first time slot into a second time slot for transmission to said second mobile station, forming a second communication signal;

receiving at said second mobile station in said second time slot the second communication signal sent from said first mobile station;

detecting at said second mobile station a first electric field intensity of said first communication signal from said base station, said second mobile station determining whether or not said first electric field intensity is sufficient to carry on communication between said base station and said second mobile station and receiving said first communication signal and said first information signal contained therein at said second mobile station from said base station when said first electric field intensity is sufficient;

determining at said second mobile station whether or not a second electric field intensity of a carrier signal from said first mobile station is sufficient to carry on communication between said second mobile station and said first mobile station; and

repeating said first communication signal at said first mobile station as said second communication signal, wherein said first mobile station changes said first information signal in said first time slot to a second information signal in said second time slot for transmitting to said second mobile station when said first electric field intensity is insufficient and said second electric field intensity is sufficient to carry on communication between said first mobile station and said second mobile stations;

transmitting from said second mobile station in a third time slot a third communication signal towards said base station, said third communication signal being received by said first mobile station; and

when said third communication signal is received from said second mobile station at said first mobile station, moving the third communication signal received in said third time slot into a fourth time slot for transmission to said base station.

2. A mobile communication network operable according to time division multiplexing, comprising:

a base station having a service area;

a first mobile station in said service area; and

a second mobile station movable in said service area and beyond a boundary of said service area;

wherein communication is possible between said base station and said second mobile station by using said first mobile station as a repeater station when said second mobile station is near or beyond said boundary;

said first mobile station being configured to receive a first communication signal sent in a first time slot from said base station and being further configured to move said first communication signal into a second time slot for transmitting said first communication signal to said second mobile station when said second mobile station is near or beyond said boundary;

said first mobile station being configured to receive a second communication signal sent in a third time slot from said second mobile present near or beyond said boundary and being configured to move said second communication signal into a fourth time slot for transmitting said second communication signal to said base station;

wherein said base station is configured to transmit said first communication signal, wherein said first communication signal contains a first information signal;

said second mobile station having a means for determining whether or not a first electric field intensity of said first communication signal is sufficient to carry on communication between said second mobile station and said base station, said means for determining means also determining whether or not a second electric field intensity of a carrier signal from said first mobile station is sufficient to carry on communication between said second mobile station and said first mobile station;

said second mobile station being configured to receive said first communication signal and said first information signal contained in said first communication signal from said base station when said first electric field intensity is sufficient to carry on communication between said second mobile station and said base station;

said first mobile station serving as said repeater station to repeat said first communication signal when said first electric field intensity is insufficient to carry on communication between said second mobile station and said base station and said second electric field intensity is sufficient to carry on communication between said second mobile station and said first mobile station, said first mobile station having a means for changing said first information signal to a second information signal for transmitting to said second mobile station.

3. A mobile communication network as claimed in claim 2, wherein each mobile station of said first and said second mobile stations comprises:

receiving means for receiving a first transmission signal as a first received signal from one of said base station and others of said mobile stations by using an information signal corresponding to said first time slot in said first transmission signal;

transmitting means for transmitting a second transmission signal in said second time slot to said one of base station and others of said mobile stations with an information signal corresponding to said second time slot is included in said second transmission signal;

level judging means for judging a reception level of said first received signal to produce a control signal in compliance with the information signal when said reception level is greater than a predetermined level; and

slot disposing means responsive to said control signal for producing the information signal corresponding to said second time slot and for disposing contents of said first received signal in said second transmission signal when said reception level is not greater than said predetermined level.

4. A mobile communication network as claimed in claim 3, wherein:

said receiving means is configured to receive said first transmission signal from said base station in response to said control signal;

said transmitting means is configured to receive said second transmission signal in response to said control signal.

5. A mobile communication network as claimed in claim 3, wherein:

said receiving means receives said first transmission signal from one of said other of mobile stations when said reception level is not greater than said predetermined level;

said level judging means producing said control signal when said predetermined level is exceeded by the reception level of the first received signal received from said one of others of mobile stations;

said transmitting means transmitting said second transmission signal to said one of others of mobile stations in response to said control signal.

6. A mobile station for use in a mobile communication network, operable according to time division multiplexing, which includes a base station having a service area and other stations movable in said service area and beyond a boundary of said service area, comprising:

a mobile station being movable in said service area and capable of direct communication with said base station and capable of serving as a repeating station for communication between said base station and at least one of said other stations when said at least one of said other stations is near said boundary or outside said service area and has a communication area covering said mobile station;

wherein said mobile station is configured to receive a first communication signal sent in a first time slot from said base station and is configured to move said first communication signal into a second time slot for transmitting to said at least one of stations; and

wherein said mobile stations are further configured to receive a second communication signal sent in a third time slot from said at least one of others of mobile stations and configured to move said second communication signal into a fourth time slot for transmitting to said base station; and

wherein said first communication signal sent from said base station contains a first information signal;

said at least one of said other stations being capable of determining whether or not a first electric field intensity of said first information signal is sufficient to carry on communication between said base station and said at least one of said other stations, and being further capable of determining whether or not a second electric field intensity is sufficient to carry on communication between said mobile station and said at least one of said other stations;

said at least one of other of mobile stations configured to receive said first communication signal by using said first information signal when said first electric field intensity is sufficient to carry on communication between said base station and said at least one of said other stations;

said mobile station serving as said repeater station to repeat said first communication signal to said at least one of said other stations when said first electric field intensity is insufficient to carry on communication between said base station and said at least one of said other stations and said second electric field intensity is sufficient to carry on communication between said mobile station and said at least one of said other stations;

said mobile station having means for changing said first information signal in said first communication signal to a second information signal in said second communication signal for transmitting said repeated information signal to said at least one of stations.

7. A mobile station as claimed in claim 6, further comprising:

receiving means for receiving a first transmission signal as a first received signal from one of said base station and said other stations by using an information signal corresponding to said first slot in said first transmission signal;

transmitting means for transmitting a second transmission signal in said second time slot to said one of base station and other stations with an information signal corresponding to said second time slot is included in said second transmission signal;

said judging means for judging a reception level of said first received signal to produce a control signal in compliance with the information signal when said reception level is greater that a predetermined level; and

slot disposing means responsive to said control signal for producing the information signal corresponding to said second time slot and for disposing contents of said first received signal in said second transmission signal when said reception level is not greater than said predetermined level.

8. A mobile station as claimed in claim 7, wherein:

said receiving means is configured to receive said first transmission signal from said base station in response to said control signal;

said transmitting means is configured to transmit said second transmission signal in response to said control signal to said base station.

9. A mobile station as claimed in claim 7, wherein:

said receiving means receives said first transmission signal from one of said other stations when said reception level is not greater than said predetermined level;

said level judging means producing said control signal when said predetermined level is exceeded by the reception level of the first received signal received from said one of other stations;

said transmitting means transmitting said second transmission signal to said one of other stations in response to said control signal.

10. A mobile communication network comprising:

a base station having a service area; and

a plurality of mobile stations including a first mobile station in said service area, and a second mobile station movable in said service area and beyond a boundary of said service area;

each of said plurality of mobile stations including;

receiving means for receiving a first transmission signal as a first received signal from one of said base station and others of said plurality of mobile stations by using an information signal contained in said first transmission signal corresponding to a first time slot in said first transmission signal;

transmitting means for transmitting a second transmission signal in a second time slot to said one of base station and others of said plurality of mobile stations with an information signal corresponding to said second time slot included in said second transmission signal;

level judging means for judging a reception level of said first received signal to produce a control signal in compliance with the information signal corresponding to said first time slot when said reception level is greater than a predetermined level; and

slot disposing means responsive to said control signal for producing the information signal corresponding to said second time slot and for disposing contents of said first received signal in said second transmission signal when said reception level is not greater than said predetermined level;

wherein communication is possible between said base station and said second mobile station by using said first mobile station as a repeater station when said second mobile station is near or beyond said boundary.

11. A mobile communication network as claimed in claim 10, wherein:

said receiving means is configured to receive said first transmission signal from said base station in response to said control signal;

said transmitting means is configured to receive said second transmission signal in response to said control signal.

12. A mobile communication network as claimed in claim 10, wherein:

said receiving means receives said first transmission signal from said one of said plurality of mobile stations when said reception level is not greater than said predetermined level;

said level judging means producing said control signal when said predetermined level is exceeded by the reception level of the first received signal received from said one of said plurality of mobile stations;

said transmitting means transmitting said second transmission signal to said one of said plurality of mobile stations in response to said control signal.

13. A mobile station for use in a mobile communication network which includes a base station having a service area and other mobile stations movable in said service area and beyond a boundary of said service area, comprising:

receiving means for receiving a first transmission signal in as a first received signal from one of said base station and said other stations by using an information signal correponding to a first time slot in said first transmission signal;

transmitting means for transmitting a second transmission signal in a second time slot to said one of base station and other mobile stations with an information signal corresponding to said second time slot included in said second transmission signal;

said judging means for judging a reception level of said first received signal to produce a control signal in compliance with the information signal corresponding to said first time slot when said reception level is greater that a predetermined level; and

slot disposing means responsive to said control signal for producing the information signal corresponding to said second time slot and for disposing contents of said first received signal in said second transmission signal when said reception level is not greater than said predetermined level;

said mobile station being movable in said service area and capable of direct communication with said base station and capable of serving as a repeating station for communication between said base station and at least one of said other mobile stations when said at least one of said other mobile stations is near said boundary or outside said service area and has a communication area covering said mobile station.

14. A mobile station as claimed in claim 13, wherein:

said receiving means is configured to receive said first transmission signal from said base station in response to said control signal;

said transmitting means is configured to transmit said second transmission signal in response to said control signal to said base station.

15. A mobile station as claimed in claim 13, wherein:

said receiving means receives said first transmission signal from one of said other mobile stations when said reception level is not greater than said predetermined level;

said level judging means producing said control signal when said predetermined level is exceeded by the reception level of the first received signal received from said one of other mobile stations;

said transmitting means transmitting said second transmission signal to said one of other mobile stations in response to said control signal.