Method and apparatus for locating which zone and sector of a mobile communication system a mobile station is in

• US 5,230,081 A
• Filed: 06/26/1991
• Issued: 07/20/1993
• Est. Priority Date: 09/19/1989
• Status: Expired due to Fees

• Current Assignee: NTT Mobile Communications Network Inc. (Nippon Telegraph and Telephone Corporation)
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Yamada, Tomoyuki, Onoe, Seizo, Utano, Takanori, Umeda, Narumi
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Pham, Chi H.
• Application Number:
  US07/689,834
• Time in Patent Office: 755 Days
• Field of Search: 455/33.1-33.4, 455/54.1, 455/54.2, 455/56.1, 455/67.1, 455/226.1, 455/226.2, 455/226.3, 455/34.1, 379/59, 379/60, 379/63
• US Class Current: 455/456.3
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A location method and system for a mobile communication system having a plurality of zones and a plurality of sectors in each zone. The location method and system locate a zone and sector in a zone where a mobile station is located. In the location system a base station associated with each zone transmits a control channel signal and transmits a sector signal for each sector in the zone. Each control signal of a zone differs from control channel signals of other zones. Each sector signal differs from other sector signal and control channel signals. A mobile station controller associated with each mobile station receives the control channel signals, determines which zone the mobile station is in as a location zone based on the received control channel signals, receives sector signals for sectors within the location zone, and determines which sector of the location zone the mobile station is in as a location sector based on the received sector signals.

Claims

1. A location system for a mobile communication system having a plurality of zones and a plurality of sectors in each zone, the location system locating a particular zone and sector in which a mobile station is located, the location system comprising:

a base station means associated with each zone for transmitting a control channel signal for its associated zone, each zone'"'"'s control channel signal being different from those of other zones, and for transmitting a sector signal for each sector in the zone, each sector signal being different from other sector signals and control channel signals; and

mobile station means associated with each mobile station for receiving control channel signals, determining which zone the mobile station is in a location zone based on the received control channel signals, receiving sector signals for sectors within the location zone, and determining which sector of the location zone the mobile station is in a location sector based on the received sector signals.

2. The location system of claim 1, wherein the base station means comprises base transmitter/receiver means for transmitting the control channel signal and a sector signals via directional antennas, each directional antenna being associated with a sector, the base transmitter/receiver means transmitting the control channel signal via the directional antennas and transmitting each sector signal via a corresponding directional antenna.

3. The location system of claim 1, wherein the mobile station means comprises:

mobile transmitter/receiver means for receiving signals including the control channel signals and sector signals;

filter means for selecting a received signal;

measuring means for measuring the receiving level of the selected received signal;

control means for controlling the filter means to select the received control channel signals, determining as the location zone a zone associated with a control channel signal having the highest receiving level, controlling the filter means to select the sector signals associated with the sectors in the location zone, and determining as the location sector a sector associated with a sector signal having the highest receiving level.

4. The location system of claim 3, wherein the mobile station means comprises:

a frequency memory means for storing frequencies of the control channel signals and frequencies of the sector signals associated with each control channel signal;

wherein

the filter means selects a received signal based on a desired frequency output by the control means; and

the control means inputs the frequencies of the control channel signals from the frequency memory means, outputs the frequencies of the control channel signals to the filter means as desired frequencies, inputs the frequencies of the sector signals associated with the sectors in the location zone from the frequency memory means, and outputs the frequencies of the sector signals associated with the sectors in the location zone to the filter means as desired frequencies.

5. The location system of claim 3, wherein

the base station means transmits identification signals indicating frequencies of the control channel signals and indicating frequencies of the sector signals associated with the sectors of each zone;

and

the filter means selects a received signal based on a desired frequency output by the control means; and

the control means controls the filter means to select the identification signals, determines the frequencies of the control channels signals from the identification signals, outputs the frequencies of the control channel signals to the filter means as desired frequencies, determines the frequencies of the sector signals associated with sectors in the location zone based on the identification signals, and outputs the frequencies of the sector signals associated with the sectors in the location zone to the filter means as desired frequencies.

6. The location system of claim 5, wherein

the mobile station means further comprises frequency memory means for storing the frequencies of the control channel signals and the frequencies of the sector signals, the stored frequencies being addressable based on a corresponding identification address;

wherein

the base station means transmits the identification signals each indicating a different identification address; and

the control means inputs the frequencies of the control channels and the sector signals associated with the sectors in the location zone from the frequency memory means using the identification addresses.

7. The location system of claim 1, wherein the mobile station means further performs the function of detecting movement of the mobile station from one sector to another within a zone.

8. The location system of claim 7, wherein the mobile station means further comprises:

mobile transmitter/receiver means for receiving signals including the control channel signals and the sector signals;

filter means for selecting a received signal;

measuring means for measuring the receiving level of the selected received signal;

control means for controlling the filter means to select the control channel signal associated with the location zone and the sector signal associated with the location sector, determining a ratio of a receiving level of the sector signal associated with the location sector to a receiving level of the control channel signal associated with the location zone, comparing the ratio to a predetermined value, and determining that the mobile station has moved to a new sector based on the comparison.

9. The location system of claim 1, wherein the mobile station means further performs the function of detecting movement of the mobile station from one zone to another.

10. The location system of claim 9, wherein the mobile station means comprises:

mobile transmitter/receiver means for receiving signals including the control channel signals and the sector signals;

filter means for selecting a received signal;

measuring means for measuring the receiving level of the selected received signal;

control means for controlling the filter means to select the control channel signal associated with the location zone and control channel signals associated with zones adjacent to the location zone, determining a ratio of a receiving level of a control channel signal associated with an adjacent zone to a receiving level of the control channel signal associated with the location zone, comparing the ratio to a predetermined value, and determining that the mobile station has moved to the adjacent zone based on the comparison.

11. The location system of claim 10, wherein the mobile station mean comprises memory means for storing which zones are adjacent to each zone and control channel signals thereof, and the control means inputs from the memory means control channel signals of zones adjacent to the location zone.

12. The location system of claim 10, wherein the base station means transmits identification signals indicating that zones are adjacent to each zone and control channel signals thereof, and the control means determines control channel signals of zones adjacent to the location zone based on the identification signals.

13. A location method for a mobile communication system having a plurality of zones and a plurality of sectors within each zone, the location method locating which zone and sector within the zone a mobile station is in, each zone associated with a base station, each base station transmitting signals including a control channel signal and sector signals, each control channel signal differing from control channel signals of other zones, and each sector signal being associated with a sector in a zone and differing rom other sector signals and control channel signals, the method comprising the steps of:

receiving signals on a mobile station'"'"'s transmitter/receiver including control channel signals and sector signals;

first measuring a receiving level of each control channel signal using a receiving level detector of the mobile station;

first determining which zone the mobile station is in as a location zone based on the receiving levels of the control channel signals using a controller of the mobile station;

second measuring a receiving level of each sector signal associated with the sectors in the location zone using the receiving level detector; and

second determining which sector of the location zone the mobile station is in as a location sector based on the receiving levels of the sector signals associated with the sectors in the location zone using the controller of the mobile station.

14. The location method of claim 13, wherein

the first measuring step includes the steps of:

first filtering the received signals to obtain each control channel signal using a filter means of the mobile station, and

first detecting the receiving level of each obtained control channel signal using the receiving level detector of the mobile station; and

the second measuring step includes the steps of;

second filtering the received signals to obtain each sector signal of sectors in the location zone using a filter means of the mobile station, and

second detecting the receiving level of each obtained sector signal associated with the sectors in the location zone using receiving level detector of the mobile station.

15. The location method of claim 13, wherein

the first determining step includes the steps of determining which control channel signal has the highest receiving level, and designating the zone associated with the control channel signal having the highest receiving level as the location zone;

and

the second determining step includes the steps of determining which sector signal of the sectors in the location zone has the highest receiving level, and designating the sector associated with the sector signal having the highest receiving level as the location sector.

16. The location method of claim 13, further comprising the steps of:

third determining a ratio of the receiving level of the sector signal associated with the location sector to the receiving level of the control channel signal associated with the location zone;

comparing the ratio to a predetermined value; and

fourth determining that the mobile station has moved to a new sector based on results of the comparison step.

17. The location method of claim 13, further comprising the steps of:

determining a ratio of the receiving level of a control channel signal associated with an adjacent zone to the receiving level of the control channel signal associated with the location zone;

comparing the ratio to a predetermined value;

determining that the mobile station has moved to a new zone based on the results of the comparison step.

18. A location method for a mobile communication system having a plurality of zones and a plurality of sectors in each zone, the location method locating which zone and sector within a zone a mobile station is in, the method comprising the steps of:

transmitting a control channel signal and sector signals for each zone from a corresponding base station, each control channel signal of a zone differing from control channel signals of other zones, and each sector signal being associated with a sector in a zone and differing from other sector signals and control channel signals;

receiving signals on a mobile station'"'"'s transmitter/receiver including control channel signals and sector signals;

first measuring a receiving level of each control channel signal using a receiving level detector of the mobile station;

first determining which zone the mobile station is in as a location zone based on the receiving levels of the control channel signals using a controller of the mobile station;

second measuring a receiving level of each sector signal associated with the sectors in the location zone using the receiving level detector; and

second determining which sector of the location zone the mobile station is in as a location sector based on the receiving levels of the sector signals associated with the sectors in the location zone using the controller of the mobile station.