METHOD AND SYSTEM FOR SYNCHRONIZATION OF AT LEAST TWO TERMINAL COMMUNICATION SYSTEMS AND AT LEAST ONE COUNTERPART COMMUNICATION STATION WITHIN A MULTI-STANDARD WIRELESS COMMUNICATION SYSTEM

• US 20100113014A1
• Filed: 11/09/2009
• Published: 05/06/2010
• Est. Priority Date: 05/09/2007
• Status: Active Grant

• Current Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Original Assignee: ST-Ericcson SA (Telefonaktiebolaget LM Ericsson)
• Inventors: Wuensch, Christian, Neumann, Markus
• Granted Patent: US 8,457,103 B2
• Time in Patent Office: Days
• US Class Current: 455/426.100
• CPC Class Codes: H04B 7/2675 Frequency synchronisation
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A method synchronizes plural terminal communication systems and a counterpart communication station connected via a radio link within a multi-standard wireless communication system, wherein a counterpart transmission signal is transmitted from said counterpart communication station to the corresponding terminal communication system. A common reference clock signal is generated and supplied to a signal generation unit within said terminal communication system, wherein each terminal communication system comprises a conversion ratio unit having a conversion ratio. An accurate frequency datum is derived from each counterpart transmission signal in the terminal communication systems and a frequency control signal is determined from said accurate frequency datum. A synchronization between said terminal communication stations and counterpart communication station is obtained by adjusting the frequency of the common reference clock signal and/or the conversion ratio of said conversion ratio units according to the frequency control signal.

Claims

1. A method, comprising:

synchronizing a plurality of terminal communication systems and a counterpart communication station coupled via a radio link within a multi-standard wireless communication system, the synchronizing including;

transmitting a counterpart transmission signal from said counterpart communication station to a corresponding terminal communication system of the plurality of terminal communication systems;

generating a common reference clock signal;

supplying said common reference clock signal to a signal generation unit within said terminal communication systems, wherein each terminal communication system comprises a conversion ratio unit having a respective conversion ratio;

deriving an accurate frequency datum from said counterpart transmission signal;

determining a frequency control signal based on said accurate frequency datum; and

obtaining synchronization between said corresponding terminal communication system and the counterpart communication station, the obtaining including at least one of;

adapting a frequency of the common reference clock signal according to the frequency control datum; and

adapting the conversion ratio of said conversion ratio unit of the corresponding terminal communication system according to the frequency control datum.

2. A method according to claim 1, comprising:

sharing among the terminal communication systems at least one of the accurate frequency datum and the frequency control signal determined from said accurate frequency datum.

3. A method according to claim 1, comprising:

deriving a plurality of accurate frequency data, via a plurality of signal conversion units, respectively, from a plurality of counterpart transmission signals, respectively; and

deriving a plurality of frequency control signals in the terminal communication systems, respectively, from the accurate frequency data, respectively.

4. A method according to claim 3, wherein each terminal communication system includes a respective one of a plurality of signal generating units, the method comprising, for each terminal communication system, supplying said frequency control signal that was derived in the terminal communication system to the signal generation unit of the terminal communication system.

5. A method according to claim 3, comprising:

deriving a common frequency control signal from the frequency control signals; and

controlling the frequency of the common reference clock signal via said common frequency control signal.

6. A method according to claim 5, wherein deriving the common frequency control signal comprises:

prioritizing the frequency control signal provided by the terminal communication system that is most accurate; and

selecting the prioritized frequency control signal as the common reference clock signal.

7. A method according to claim 5, comprising:

detecting a discontinuous operation of one of the terminal communication systems; and

applying a buffered frequency control signal while the at least one of the terminal communication systems is inactive.

8. A method according to claim 5, wherein deriving the common frequency control signal is performed by a clock control evaluation unit, the method comprising:

selecting as the common frequency control signal whichever one of the terminal communication systems is currently active, wherein the activeness of the terminal communication systems is determined by an operation mode detector arranged within the clock control evaluation unit.

9. A method according to claim 3, comprising:

deriving, using a common clock control unit, the frequency control signal from the accurate frequency data provided by the signal conversion units; and

controlling the conversion ratio of said conversion ratio units via said frequency control signal.

10. A method according to claim 9, wherein deriving the frequency control signal comprises:

prioritizing the accurate frequency data provided by the signal conversion units; and

selecting one prioritized accurate frequency datum for deriving said frequency control signal.

11. A method according to claim 9, comprising:

detecting a discontinuous operation of at least one of the terminal communication systems; and

using a buffered frequency control signal as the frequency control signal while the at least one of the terminal communication systems is inactive.

12. A method according to claim 9, comprising:

selecting one of the accurate frequency data provided by currently active terminal communication systems of the terminal communication systems as the frequency control signal, wherein the activeness of the terminal communication systems is determined by the common clock control unit.

13. A method according to claim 1, comprising:

detecting a frequency offset datum in one of the terminal communication systems by comparing said common reference clock signal with the accurate frequency datum and

deriving said frequency control signal from the detected frequency offset datum.

14. A multi-standard wireless communication system, comprising:

a common reference clock unit configured to generate a common reference clock signal; and

a plurality of radio communication systems, each radio communication system including a terminal communication system and a counterpart communication station coupled to each other via radio link, each counterpart communication station being configured to transmit a counterpart transmission signal to the terminal communication system of the radio communication system, each terminal communication system including;

a signal generation unit including a conversion ratio unit having a corresponding conversion ratio, the signal generation being configured to receive the common reference clock signal from the common reference clock unit; and

a signal conversion unit configured to derive an accurate frequency datum from the counterpart transmission signal received by the terminal communication system;

wherein one of the terminal communication systems includes;

a clock control unit configured to determine a frequency control signal based on said accurate frequency datum, wherein the common reference clock unit is configured to adjust a frequency of the common reference clock signal according to the frequency control signal and/or said conversion ratio units are configured to adjust their respective conversing ratios according to the frequency control signal.

15. A system according to claim 14, wherein each signal generation unit is realized by a Frac-N divider phase locked loop unit.

16. A system according to claim 14, wherein said conversion ratio units each include an integer divider unit, a frac-N divider unit or a divider unit working according to a division technique.

17. A system according to claim 14, wherein said terminal communication systems are configured to share the accurate frequency datum and/or the frequency control signal among the different communication stations.

18. A system according to claim 14, wherein the clock control unit is one of a plurality of clock control units, each terminal communication system including a respective clock unit of the plurality of clock control units, wherein for each of the terminal communication systems, said clock control unit of the terminal communication system is configured to derive a respective individual frequency control signal from the accurate frequency datum derived by the signal conversion unit of the terminal communication system and supply said individual frequency control signal to the signal generation unit of the terminal communication system.

19. A system according to claim 14, wherein the clock control unit is one of a plurality of clock control units, each terminal communication system including a respective clock unit of the plurality of clock control units, wherein for each of the terminal communication systems, said clock control unit of the terminal communication system is configured to derive a respective individual frequency control signal from the accurate frequency datum derived by the signal conversion unit of the terminal communication system, the system further comprising a common clock control evaluation unit configured to derive a common frequency control signal from the individual frequency control signals and control the frequency of the common reference clock signal based on said common frequency control signal.

20. A system according to claim 14, wherein the clock control unit is configured to derive the frequency control signal from the accurate frequency data of all of the signal conversion units and control the conversion ratios of the said conversion ratio units using said frequency control signal.

21. A system according to claim 20, wherein said clock control unit comprises a multiplexer unit, an operation mode detector and a memory unit.

22. A system according to claim 21, wherein the operation mode detector is arranged between the multiplexer unit and the memory unit and is configured to determine whether the terminal communication systems are active.

23. A system according to claim 21, wherein the memory unit is an analog memory.

24. A system according to claim 20, wherein the common reference clock unit is a fixed frequency oscillator.

25. A system according to claim 24, wherein the fixed frequency oscillator is a micro-electro-mechanical system oscillator.