Synchronization scheme with adaptive reference frequency correction
View Patent ↗An apparatus and a method provide synchronization of an output signal to a synchronization information. The synchronization is accomplished by providing coupling of a correction control information that controls a signal generator, e.g. a phase locked loop arrangement or a direct digital synthesis arrangement, to its exact frequency to a frequency conversion unit that converts an uncorrected reference frequency to a correct or exact reference frequency. Thereby, the uncorrected reference frequency for the signal generator can be provided by a simple crystal oscillator without any frequency controller. The setting of the signal generator and the frequency conversion unit can be done in a predetermined sequence which enables a user equipment to synchronize its reference frequency to the synchronization information emitted by a communication network.
1. A synchronization apparatus, comprising:
a frequency converter configured to convert, based on correction control information, a reference frequency into a corrected reference frequency for processing a received synchronization signal; and
a frequency correction controller configured to generate the correction control information based on a determined synchronization error with respect to said synchronization signal.
2. An apparatus according to claim 1 , wherein said frequency correction controller is configured to determine the synchronization error based on a synchronization error between an output signal, having the corrected reference frequency, and said synchronization signal.
3. An apparatus according to claim 1 , wherein said frequency correction controller is configured to determine the synchronization error based on a synchronization error between said reference frequency and a frequency of said synchronization signal.
4. An apparatus according to claim 1 , further comprising a phase lock loop configured to receive said reference frequency and generate a conversion signal, wherein said frequency correction controller is configured to determine the synchronization error based on a synchronization error between said conversion signal and said synchronization signal.
5. An apparatus according to claim 4 , wherein said phase lock loop is configured to set an initial division ratio based on channel control information, and set a frequency correction division ratio based on said correction control information.
6. An apparatus according to claim 5 , further comprising a programming interface coupled to the frequency correction controller and configured to provide said correction control information to said frequency converter and said channel control information to said phase lock loop.
7. An apparatus according to claim 1 , wherein said frequency converter comprises:
a multiplier configured to multiply said reference frequency by a multiplication factor determined based on a frequency correction addend, which is derived from said correction control information, and an independent conversion factor; and
a divider configured to divide said multiplied reference frequency by a division factor based on said independent conversion factor.
8. An apparatus according to claim 7 , wherein said frequency correction controller is configured to set said independent conversion factor to obtain an integer value of said multiplication factor.
9. An apparatus according to claim 1 , further comprising a switch configured to selectively supply said reference frequency and an output of said frequency converter to a baseband processing unit coupled to said frequency correction controller.
10. A radio communication device comprising:
an antenna configured to receive a synchronization signal; and
a synchronization apparatus that includes:
a frequency converter configured to convert, based on correction control information, a reference frequency into a corrected reference frequency for processing the synchronization signal; and
a frequency correction controller configured to generate the correction control information based on a determined synchronization error with respect to said synchronization signal.
11. A device according to claim 10 , wherein said frequency correction controller is configured to determine the synchronization error based on a synchronization error between an output signal, having the corrected reference frequency, and said synchronization signal.
12. A device according to claim 10 , wherein said frequency correction controller is configured to determine the synchronization error based on a synchronization error between said reference frequency and a frequency of said synchronization signal.
13. A device according to claim 10 , wherein the apparatus includes a phase lock loop configured to receive said reference frequency and generate a conversion signal, wherein said frequency correction controller is configured to determine the synchronization error based on a synchronization error between said conversion signal and said synchronization signal.
14. A device according to claim 13 , wherein said phase lock loop is configured to set an initial division ratio based on channel control information, and set a frequency correction division ratio based on said correction control information.
15. A device according to claim 14 , wherein the apparatus includes a programming interface coupled to the frequency correction controller and configured to provide said correction control information to said frequency converter and said channel control information to said phase lock loop.
16. A device according to claim 15 , wherein the phase lock loop is configured to derive the initial division ratio from a ratio between a frequency of the synchronization signal and the reference frequency.
17. A device according to claim 10 , wherein said frequency converter comprises:
a multiplier configured to multiply said reference frequency by a multiplication factor determined based on a frequency correction addend, which is derived from said correction control information, and an independent conversion factor; and
a divider configured to divide said multiplied reference frequency by a division factor based on said independent conversion factor.
18. A device according to claim 17 , wherein said frequency correction controller is configured to set said independent conversion factor to obtain an integer value of said multiplication factor.
19. A device according to claim 10 , wherein the apparatus includes a switch configured to selectively supply said reference frequency and an output of said frequency converter to a baseband processing unit coupled to said frequency correction controller.