Parameter estimate initialization using interpolation

• US 7,558,533 B2
• Filed: 11/07/2007
• Issued: 07/07/2009
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Ramesh, Rajaram, Cozzo, Carmela, Bottomley, Gregory
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US11/936,193
• Publication Number:
  US 20080063045A1
• Time in Patent Office: 608 Days
• Field of Search: 455/504, 455/506, 455/65, 455/67.16, 455/132, 455/137, 375/150, 375/142, 375/343, 375/347, 370/342
• US Class Current: 455/65
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• CPC Class Codes: H04B 2201/709727 GRAKE type RAKE receivers

Abstract

A receiver is described herein that is capable of receiving and processing a radio signal and further capable of using interpolation to initialize receiver parameters when there is a change in at least one delay associated with the received radio signal or when there is at least one new correlator position. For instance, the receiver parameters that can be initialized include: (1) channel coefficients; (2) AFC parameters; (3) tracking parameters; (4) noise statistics (noise correlations); (5) signal statistics (channel coefficient correlations); (6) data statistics (despread values or chip samples); or (7) combining weights.

Claims

1. A receiver adapted to receive and process a radio signal and initialize an initial value of a parameter, the receiver being characterized by means for:

comparing a new delay of the received signal and an old delay of a previously received signal;

if the new delay and the old delay are the same, then initializing the initial value of the parameter to be an existing value; and

if the new delay and the old delay are not the same, then interpolating information and initializing the initial value of the parameter to be the interpolated value, said act of interpolating comprising the acts of;

defining an interpolation set within which there may be one or more existing values of the parameter that could be used to initialize the initial value of the parameter;

if the interpolation set is empty, then initializing the initial value of the parameter to be zero or some other value; and

,

if the interpolation set is not empty, then interpolating the one or more existing values of the parameter and initializing the initial value of the parameter to be the interpolated value.

2. The receiver of claim 1, wherein said information used to generate the interpolated value is existing parameter estimates.

3. The receiver of claim 1, wherein said information used to generate the interpolated value is searcher information.

4. The receiver of claim 1, wherein said information used to generate the interpolated value is a combination of existing parameter estimates associated with existing delays and searcher information including at least one of a complex/delay profile (CDP) and a power/delay profile (PDP).

5. The receiver of claim 1, wherein said interpolating includes linear interpolating.

6. The receiver of claim 1, wherein said interpolating includes Wiener interpolating.

7. The receiver of claim 1, wherein said parameter is a channel coefficient.

8. The receiver of claim 1, wherein said parameter is an automatic frequency correction (AFC) parameter.

9. The receiver of claim 1, wherein said parameter is a tracking parameter.

10. receiver of claim 1, wherein said parameter is a noise statistic.

11. receiver of claim 1, wherein said parameter is a signal statistic.

12. The receiver of claim 1, wherein said parameter is a combining weight.

13. The receiver of claim 1, wherein said parameter is a data statistic.

14. The receiver of claim 13, wherein said data statistic corresponds to received sample data.

15. The receiver of claim 13, wherein said data statistic corresponds to despread data.

16. The receiver of claim 1, wherein said receiver is a RAKE receiver.

17. The receiver of claim 1, wherein said receiver is a chip equalizer.

18. The receiver of claim 1, wherein said new delay associated with the received radio signal corresponds with a new finger position when said receiver is a RAKE receiver.

19. The receiver of claim 1, wherein said new delay associated with the received radio signal corresponds with a new tap position when said receiver is a chip equalizer.

20. A wireless communication system comprising:

a transmitter adapted to transmit a radio signal; and

a receiver including;

an antenna for receiving the radio signal;

a radio frequency (RF) processor for processing the radio signal; and

a baseband processor for initializing an initial value of a parameter, characterized by means for carrying out the following steps;

comparing a new delay of the received signal and an old delay of a previously received signal;

if the new delay and the old delay are the same, then initializing the initial value of the parameter to be an existing value; and

if the new delay and the old delay are not the same, then performing the following steps;

defining an interpolation set within which there may be one or more existing values of the parameter that could be used to initialize the initial value of the parameter;

if the interpolation set is empty, then initializing the initial value of the parameter to be zero or some other value; and

if the interpolation set is not empty, then interpolating the one or more existing values of the parameter and initializing the initial value of the parameter to be the interpolated value.

21. The wireless communication system of claim 20, wherein said baseband processor includes a weight formation unit for initializing the initial value of the parameter.

22. The wireless communication system of claim 20, wherein said baseband processor is adapted to use linear interpolation to initialize the initial value of the parameter when the new delay and the old delay are not the same.

23. The wireless communication system of claim 20, wherein said baseband processor is adapted to use Wiener interpolation to initialize the initial value of the parameter when the new delay and the old delay are not the same.

24. The wireless communication system of claim 20, wherein said parameter is at least one of:

a channel coefficient;

an automatic frequency correction (AFC) parameter;

a tracking parameter;

a noise statistic;

a signal statistic;

a data statistic; and

a combining weight.

25. A method for parameter initialization in a radio signal receiver, said method comprising the steps of:

estimating a delay associated with a received radio signal; and

initializing an initial value of a parameter characterized by the steps of;

comparing a new delay of the received signal and an old delay of a previously received signal;

if the new delay and the old delay are the same, then initializing the initial value of the parameter to be an existing value; and

if the new delay and the old delay are not the same, then performing the following steps;

defining an interpolation set within which there may be one or more existing values of the parameter that could be used to initialize the initial value of the parameter;

if the interpolation set is empty, then initializing the initial value of the parameter to be zero or some other value; and

if the interpolation set is not empty, then interpolating the one or more existing values of the parameter and initializing the initial value of the parameter to be the interpolated value.

26. The method of claim 25, wherein said interpolating step is a linear interpolating step.

27. The method of claim 25, wherein said interpolating step is a Wiener interpolating step.

28. The method of claim 25, wherein said parameter is at least one of:

a channel coefficient;

an automatic frequency correction (AFC) parameter;

a tracking parameter;

a noise statistic;

a signal statistic;

a data statistic; and

a combining weight.

29. A receiver that receives and processes a radio signal and when there is a change in a delay associated with the received radio signal initializes diagonal elements of a channel covariance matrix (R_c) characterized by means for:

determining if a power/delay profile (PDP) value exist at the new delay associated with the received radio signal;

if the PDP value exist, then subtracting noise power from the PDP value and assigning the resulting subtracted value to the diagonal elements of the channel covariance matrix; and

if the PDP value does not exist, then performing the following steps;

choosing a set of previous PDP values;

interpolating the previous PDP values to obtain an interpolated PDP value;

subtracting noise power from the interpolated PDP value; and

assigning the resulting subtracted value to the diagonal elements of the channel covariance matrix.