Arrangement in mobile telecommunications systems for providing synchronization of transmitters of base stations

• US 5,809,426 A
• Filed: 05/12/1995
• Issued: 09/15/1998
• Est. Priority Date: 10/27/1992
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson, Unifill S.p.A.
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nilsson, Goran, Radojevic, Milan, Carlsson, Staffan
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US08/411,630
• Time in Patent Office: 1,222 Days
• Field of Search: 455/51.1, 455/51.2, 455/54.1, 455/54.2, 455/56.1, 455/18, 455/57.1, 455/33.1, 455/33.2, 455/63, 455/503, 455/502, 455/517, 455/524, 455/526, 455/439, 375/356, 375/358
• US Class Current: 455/502
• CPC Class Codes: H04B 7/2693 Centralised synchronisation, i.e. using external universal time reference, e.g. by using a global positioning system [GPS] or by distributing time reference over the wireline network
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging

Abstract

An arrangement in a mobile telecommunication system which has two or more base stations having transmitting elements which are each arranged to operate with a respective real-time clock and a time-comparing element. A central coordinating unit in the system is arranged to transmit a first time signal to an element arranged in the base station for receiving the first time signal. The first time information is then transferred together with a second time information to the time-comparing element. The second time information is set up by the real-time clock in the transmitting element. The first time information and second time information are placed in relation to one another and, in dependence on the relationship between these and existing criteria, for example delays and the like, the time-comparing element adjusts the real-time clock so that synchronization is carried out.

Claims

1. In a mobile telecommunication system including a number of base stations having transmitters and means for coordinating the base stations, an arrangement for providing for time coordination of a number of transmitters of the base stations, comprising in each base station:

a transmitting element which is arranged to operate with a respective real-time clock;

a time-comparing element;

means for receiving a first common time information transmitted from the coordinating means to the base stations, and for supplying the first common time information on to the time-comparing element together with a second time information set up from the real-time clock, the first common time information being stable over a long time period and the second time information being stable of short time period;

wherein the time-comparing element places the first common time information in relation to the second time information;

the time-comparing element adjusts the real-time clock according to at least one predetermined criterion and a relation between the first common time information and the second time information for synchronizing the respective base station with at least one other base station; and

the time-comparing element, the receiving means, and the real-time clock form a closed phase-locking system in which the receiving means processes the first common time information that is received into a format comprehensible to the time-comparing element, whereby the second time information is made stable over the long time period.

2. The arrangement of claim 1, wherein the real-time clock is set to UTC time.

3. The arrangement of claim 1, wherein the first common time information is a signal from a global positioning system.

4. The arrangement of claim 1, wherein the real-time clock produce timing information with a time delay that is respective to the base station and corresponding amount.

5. The arrangement of claim 1, wherein all base stations in the telecommunication network are synchronized.

6. The arrangement of claim 1, wherein the transmitting element operates with a buffer for storing outgoing transmit data that are clocked out to the transmitting element, and the transmitting element is responsive to a pulse-generating unit for generating the second time information set up from the real-time clock used in synchronized transmission.

7. The arrangement of claim 1, wherein a communication element is set up for transferring transmit data to the transmitting element and for transferring time information to the time-comparing element.

8. The arrangement of claim 1, wherein the telecommunication system is a digital network, preferably a paging system.