Mobile communication system and method of controlling synchronization between base stations

• US 20010038622A1
• Filed: 11/30/2000
• Published: 11/08/2001
• Est. Priority Date: 11/30/1999
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kato, Kenichi
• Granted Patent: US 7,002,948 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04B 7/2684 Synchronisation of a mobile station with more than one base station
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 92/045 between access point and backbone network device

Abstract

A mobile communication system has a plurality of base stations which are located at appropriate positions within a predetermined area and conduct radio communication with a mobile communication terminal, and an exchange office which is connected with the base stations and conducts the exchange control toward an external network, and which offers a Time Division Multiplex radio communications by supplying a synchronizing signal to each of the base stations. The system further has delay time detection means for detecting an arrival delay time of the synchronizing signal to each of the base stations, computation means for computing a timing correction value which synchronizes a radio communication timing of all of the base stations for each base station on the basis of a delay time detected, and correction means for correcting the synchronizing signal supplied to the base stations according to the timing correction value.

Claims

1. A mobile communication system comprising a plurality of base stations which are located at appropriate positions within a predetermined area and conduct radio communications with a mobile communication terminal, and an exchange office which is connected with said base stations and conducts the exchange control toward an external network, said exchange office conducting a Time Division Multiplex radio communication by providing a synchronizing signal from said exchange office to each of said base stations,

said system further comprising,

delay time detection means for detecting an arrival delay time of said synchronizing signal to each of said base stations;

computation means for computing a timing correction value which synchronizes a radio communication timing of all of said base stations for each base station on the basis of a delay time detected; and

correction means for correcting said synchronizing signal supplied to said base stations according to said timing correction value.

2. A mobile communication system, according to

claim 1

, wherein:

said delay detection means comprises;

means installed in said exchange office for generating a test signal for delay time detection and sending said test signal to said base stations;

means for sending by return said test signal sent from said exchange office at said base station; and

measuring means for receiving said test signal sent by return from said base stations and for measuring a time difference between time of transmission and arrival of said test signal.

3. A mobile communication system, according to

claim 1

, wherein:

said computing means establishes a predetermined standard value and computes a difference between said standard value and a delay time of each of said base stations and said timing correction value.

4. A mobile communication system, according to

claim 2

, wherein:

said computing means establishes a predetermined standard value and computes a difference between said standard value and a delay time of each of said base stations as said timing correction value.

5. A mobile communication system, according to

claim 1

, wherein:

said system comprises switching means for selectively switching an operating conditions thereof to normal and test operating conditions, and makes said delay time detection means operate when said system is in a test operation mode.

6. A mobile communication system, according to

claim 2

, wherein:

said system comprises switching means for selectively switching an operating conditions thereof to normal and test operating conditions, and makes said delay time detection means operate when said system is in a test operation mode.

7. A mobile communication system, according to

claim 3

, wherein:

said system comprises switching means for selectively switching an operating conditions thereof to normal and test operating conditions, and makes said delay time detection means operate when said system is in a test operation mode.

8. A mobile communication system, according to

claim 4

, wherein:

said system comprises switching means for selectively switching an operating conditions thereof to normal and test operating conditions, and makes said delay time detection means operate when said system is in a test operation mode.

9. A mobile communication system according to

claim 5

, wherein:

said system executes said test operation mode when operating said system for the first time and/or terminating a maintenance operation including additional installation of said base stations.

10. A mobile communication system according to

claim 6

, wherein:

said system executes said test operation mode when operating said system for the first time and/or terminating a maintenance operation including additional installation of said base stations.

11. A mobile communication system, according to

claim 7

, wherein:

said system executes said test operation mode when operating said system for the first time and/or terminating a maintenance operation including additional installation of said base stations.

12. A mobile communication system, according to

claim 8

, wherein:

said system execute said test operation mode when operating said system for the first time and/or terminating a maintenance operation including additional installation of said base stations.

13. A method of controlling synchronization between base stations in a mobile communication system comprising a plurality of base stations which are located at appropriate positions within a predetermined area and conduct radio communications with a mobile communication terminal, and an exchange office which is connected with said base stations and conducts the exchange control toward an external network, said exchange office conducting a Time Division Multiplex radio communication by providing a synchronizing signal from said exchange office to each of said base stations,

said method comprising the steps of:

detecting an arrival delay time of said synchronizing signal to each of said base stations;

computing a timing correction value which synchronizes timing of radio communication of all the base stations on the basis of delay time detected for each of said base stations; and

correcting said synchronizing signal supplied to said base station according to said timing correction value.