Device and method for determining the deviation of the carrier frequency of a mobile radio device from the carrier frequency of a base station

• US 20050117665A1
• Filed: 01/03/2005
• Published: 06/02/2005
• Est. Priority Date: 07/04/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Infineon Technologies AG
• Inventors: Neuhaus, Holger, Becker, Burkhard
• Granted Patent: US 8,331,492 B2
• Time in Patent Office: Days
• US Class Current: 375/316
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 2027/0087 Out-of-band signals, (e.g. pilots)
• CPC Class Codes: H04L 27/14 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A device for determination of the frequency discrepancy (105) between a mobile radio and a base station which is transmitting a sequence of symbols, having a unit (6-11) for calculation of terms, with one term being formed from two symbols in the sequence received by the mobile radio, and in which case the phase difference of the two symbols can be determined from the term, a unit (14, 15) for formation of groups from the terms, with one term being assigned to one group on the basis of features of the symbols on which it is based, and a unit (39) for calculation of the discrepancy (105) on the basis of a group.

Claims

1. A device for determination of the discrepancy between the carrier frequency of a mobile radio and the carrier frequency of at least one base station, with a sequence of complex pilot symbols which is known in the mobile radio being transmitted by radio from each base station to the mobile radio, comprising:

a first unit for calculation of terms, with one term being formed from at least two different pilot symbols in the sequence received by the mobile radio, and in which case the phase difference between the two pilot symbols can be determined from the term,

a second unit for formation of groups from the terms, with one term being assigned to one group on the basis of features of the pilot symbols on which it is based, and

a third unit for calculation of the frequency discrepancy on the basis of the terms in at least one group.

2. The device as claimed in claim 1, wherein

the first unit and the second unit are in the form of a hard-wired circuit.

3. The device as claimed in claim 1, wherein

the third unit is in the form of a digital signal processor.

4. The device as claimed in claim 1, wherein

the first unit is designed to calculate complex products, with a complex product being formed from at least two different pilot symbols in the sequence received by the mobile radio, and the argument of the complex product indicating the phase difference between the two pilot symbols.

5. The device as claimed in claim 2, wherein

the first unit has a multiplier with a first input and a second input,

the first input is preceded by a circuit branch which contains a delay element and a unit for formation of the complex-conjugate value from a complex value, and

the circuit branch is fed from the one pilot symbol, and the second input is fed from the other pilot symbol.

6. The device as claimed in claim 5, wherein

the delay time of the delay element can be set and can be predetermined.

7. The device as claimed in claim 5, wherein

the delay element is formed by a rewritable memory.

8. The device as claimed in claim 1, wherein

an accumulator for adding up a variable number of terms is arranged between the first unit and the second unit.

9. The device as claimed in claim 1, wherein

the second unit is designed such that the terms, or possibly the accumulated terms, in a group are added up.

10. The device as claimed in claim 1, comprising

a rewritable memory in which the terms in the groups, or possibly the accumulated terms in the groups, can be stored.

11. The device as claimed in claim 1, wherein

the first unit and the second unit, and possibly the accumulator, are each duplicated.

12. The device as claimed in claim 11, wherein

the two first units are preceded by a fourth unit for separation of the received pilot symbols on the basis of the associated antennas of the base station which is transmitting the pilot symbols.

13. The device as claimed in claim 1, wherein

the first unit, or, if appropriate, the fourth unit, is preceded by a rewritable memory.

14. The device as claimed in claim 1, wherein

the third unit is designed to average terms or groups of terms.

15. The device as claimed in claim 1, comprising a control unit for formation of groups, and in particular for controlling the accumulation of terms in the predetermined groups.

16. The device as claimed in claim 1, wherein

the groups are formed on the basis of the association of the pilot symbols on which the terms are based with base stations and/or with transmission paths.

17. A method for determination of the discrepancy between the carrier frequency of a mobile radio and the carrier frequency of at least one base station, with a sequence of complex pilot symbols which is known in the mobile radio being transmitted by radio from each base station to the mobile radio, comprising the steps of:

(a) calculating terms, with one term being formed from at least two different pilot symbols in the sequence received by the mobile radio, and in which case the phase difference between the at least two pilot symbols can be determined from the term,

(b) forming of groups from the terms, with one term being assigned to one group on the basis of features of the pilot symbols on which it is based, and

(c) calculating the frequency discrepancy on the basis of the terms in at least one group.

18. The method as claimed in claim 17, wherein

complex products are calculated in step (a), with a complex product being formed from at least two different pilot symbols in the sequence received by the mobile radio, and the argument of the complex product indicating the phase difference between the at least two pilot symbols.

19. The method as claimed in claim 17, wherein

the terms in a group are added up in step (b).

20. The method as claimed in claim 17, wherein

the groups are formed on the basis of the association of the pilot symbols on which the terms are based with base stations and/or with transmission paths.

21. The method as claimed in claim 17, wherein

the in each case two pilot symbols of the terms from which a group is formed are separated from one another in the sequence of the pilot symbols by a predetermined number of digits.

22. The method as claimed in claim 21, wherein

a group is formed twice, with the two groups differing in the number of digits by which the pilot symbols on which their terms are in each case based, are separated from one another.