Method for radiosynchronization of base stations in a simulcasting network

• US 5,404,575 A
• Filed: 05/26/1992
• Issued: 04/04/1995
• Est. Priority Date: 03/05/1992
• Status: Expired due to Fees

• Current Assignee: Tecnomen OY
• Original Assignee: Tecnomen OY
• Inventors: Lehto, Pekka
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): VO, NGUYEN THANH
• Application Number:
  US07/888,913
• Time in Patent Office: 1,043 Days
• Field of Search: 455/51.1, 455/51.2, 455/13.2, 455/53.1, 455/56.1, 455/18, 455/69, 455/67.1, 455/67.5, 455/49.1, 455/57.1, 455/33.1, 375/107, 370/100.1, 370/103, 340/825.44, 379/59, 379/60
• US Class Current: 455/502
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency

Abstract

A method for radiosynchronization of base stations in a simulcasting network which includes a plurality of base stations to be synchronized, comprising the following steps: a.) a first set of base stations transmitting respective synchronization signals; b.) a second set of base stations receiving at least one of the respective synchronization signals for the purpose of determining several estimates of synchronization error, where each of the several estimates is an estimate of synchronization error between one of the first set of transmitting base stations and one of the second set of receiving base stations; and, c.) adjusting subsequent transmissions of particular base stations to minimize synchronization errors between base stations within the first or second set to achieve simulcast transmission of all base stations in the network, wherein the adjustment is made based upon the several estimates, and wherein each of the several estimates was obtained based upon a synchronization signal which was either received or transmitted by the particular base station being adjusted.

Claims

1. A method for radiosynchronization of base stations in a simulcasting network which includes a synchronization controller and a plurality of base stations to be synchronized, said plurality of base stations comprising a first set of base stations and a second set of base stations, comprising the following steps:

a.) said first set of base stations transmitting respective synchronization signals;

b.) said second set of base stations receiving at least one of said respective synchronization signals for the purpose of determining several estimates of synchronization error, where each of said several estimates is an estimate of synchronization error between one of said first set of transmitting base stations and one of said second set of receiving base stations, and wherein a component of the estimate of synchronization error is evaluated as a difference of

1) instant of transmission of the synchronization signal according to a clock of a sending base station; and

2) instant of reception of the synchronization signal according to a clock of a receiving base station;

c.) sending said several estimates of synchronization error to said synchronization controller; and

,

d.) said synchronization controller adjusting timing of subsequent transmission of a particular base station within said first or second set of base stations to minimize synchronization errors between base stations within said first or second set to achieve simulcast transmission of all said base stations in said network, wherein said adjustment is made based upon said several estimates, and wherein each of said several estimates was obtained based upon a synchronization signal which was either received or transmitted by the particular base station being adjusted.

3. The method according to claim 1, wherein timing of subsequent transmission of said particular base station is adjusted based upon at least two of said several estimates.

4. The method of claim 1, wherein said synchronization controller defines a synchronization plan comprising:

a) selecting base stations for transmitting the synchronization signal(s); and

b) for each base station selected to transmit, determining the time for transmitting the synchronization signal.

5. The method of claim 1, wherein said several estimates of synchronization error are processed in said synchronization controller to evaluate timing adjustments needed for each base station.

2. A method for radiosynchronization of base stations in a simulcasting network which includes a synchronization controller and a plurality of base stations to be synchronized, said plurality of base stations comprising a first set of base stations and a second set of base stations, comprising the following steps:

a.) said first set of base stations transmitting respective synchronization signals;

b.) said second set of base stations receiving at least one of said respective synchronization signals for the purpose of determining several estimates of synchronization error, where each of said several estimates is an estimate of synchronization error between one of said first set of transmitting base stations and one of said second set of receiving base stations, and wherein a component of the estimate of synchronization error is evaluated as a difference of

1) instant of transmission of the synchronization signal according to a clock of a sending base station; and

2) instant of reception of the synchronization signal according to a clock of a receiving base station;

c.) sending said several estimates of synchronization error to said synchronization controller; and

,

d.) said synchronization controller adjusting timing of subsequent transmission of a particular base station within said first or second set to reduce synchronization error between all said base stations in said network, wherein said adjustment is made based upon at least two of said several estimates, and wherein each of said at least two of said several estimates was obtained based upon a synchronization signal which was either received or transmitted by the particular base station being adjusted.