초록 ▼

An improved approach to noise estimation permits, for example, tighter closed-loop power control in a wireless communication network with attendant improvements in transmit power efficiency and network capacity. In an exemplary embodiment, the received signal-to-noise ratio (SNR) of a data signal is

An improved approach to noise estimation permits, for example, tighter closed-loop power control in a wireless communication network with attendant improvements in transmit power efficiency and network capacity. In an exemplary embodiment, the received signal-to-noise ratio (SNR) of a data signal is estimated based on noise samples obtained from one or more other signals received in association with the data signal. In general, these associated signals are characterized by the receiver's ability to extract like valued samples from them, such that pairs of these like valued signal samples may be subtracted, thereby canceling their deterministic signal components and leaving only difference values representative of the non-deterministic noise components of the signal samples. Obtaining difference values from more than one associated signal increases the sample size of difference values used in noise estimation, thereby improving the statistical basis for noise estimation and, therefore, the accuracy of SNR estimation.

대표청구항 ▼

What is claimed is: 1. A method of estimating noise for a received signal of interest over a noise estimation interval comprising: selecting a plurality of received signals that are transmitted with the received signal of interest and from which pairs of like valued samples can be obtained, to obta

What is claimed is: 1. A method of estimating noise for a received signal of interest over a noise estimation interval comprising: selecting a plurality of received signals that are transmitted with the received signal of interest and from which pairs of like valued samples can be obtained, to obtain selected signals for use in noise estimation; obtaining a sample set of noise values over the noise estimation interval from the selected signals; and estimating a noise statistic for the received signal of interest based on the sample set of noise values; wherein the number of received signals selected is based on a desired number of noise values in the sample set of noise values. 2. The method of claim 1, wherein obtaining the sample set of noise values over the noise estimation interval from the selected signals comprises: obtaining pairs of like valued samples from each of the selected signals; and subtracting one sample of each pair from the other to obtain the sample set of noise values. 3. The method of claim 2, wherein obtaining pairs of like valued samples from each of the selected signals comprises, for at least one of the selected signals, obtaining sample pairs from repeated symbols included in the at least one of the selected signals. 4. The method of claim 2, wherein obtaining pairs of like valued samples from each of the selected signals comprises despreading at least one of the selected signals at a lower-than-actual spreading gain to derive repeated symbol values, and obtaining sample pairs from the derived repeated symbol values. 5. The method of claim 2, wherein obtaining pairs of like valued samples from each of the selected signals comprises, for at least one of the selected signals, generating duplicate sample values from actual sample values obtained from the at least one of the selected signals. 6. The method of claim 5, further comprising selecting the at least one of the selected signals one or more of the plurality of received signals having a relatively high power. 7. The method of claim 5, wherein generating duplicate sample values from actual sample values comprises: generating hard decision values from corresponding soft decision values obtained from the at least one of the selected signals; and compensating the hard decision values using channel estimation parameters associated with the at least one of the selected signals. 8. The method of claim 1, wherein selecting a plurality of received signals from which pairs of like valued samples can be obtained comprises selecting at least one received signal having a repeating symbol pattern such that pairs of like valued samples can be obtained by sampling repeated symbols. 9. The method of claim 1, wherein selecting a plurality of received signals from which pairs of like valued samples can be obtained comprises selecting at least one received signal having a first CDMA spreading gain that is a multiple of a second CDMA spreading gain associated with the received signal of interest. 10. The method of claim 9, further comprising obtaining pairs of like valued samples from the at least one selected signal by despreading the at least one selected signal using the second CDMA spreading gain. 11. The method of claim 1, wherein the received signal of interest comprises a first CDMA signal and the plurality of received signals comprise at least second and third CDMA signals transmitted with the first CDMA signal, and wherein obtaining a sample set of noise values over the noise estimation interval comprises obtaining a first number of noise values from the second CDMA signal and obtaining a second number of noise values from the third CDMA signal. 12. The method of claim 11, wherein obtaining a first number of noise values from the second CDMA signal and obtaining a second number of noise values from the third CDMA signal comprise obtaining an equal number of noise values from each of the second and third CDMA signals. 13. The method of claim 11, further comprising determining a signal-to-noise ratio (SNR) for the first CDMA signal using the noise statistic determined from the second and third CDMA signals. 14. The method of claim 13, wherein the first CDMA signal comprises a traffic channel signal, such that determining the SNR for the first CDMA signal comprises determining a traffic channel SNR. 15. The method of claim 14, wherein determining a traffic channel SNR comprises: determining a signal strength for the traffic channel signal; computing a sample variance of the noise values as the noise statistic; and calculating the traffic channel SNR based on the signal strength and the sample variance. 16. The method of claim 14, further comprising performing closed-loop power control of the traffic channel signal based on the traffic channel SNR. 17. A mobile station for use in a wireless communication network, the mobile station including one or more processors operative to: select a plurality of received signals transmitted with a received signal of interest, based on the suitability of the selected received signals for obtaining pairs of like valued samples for use in noise estimation; obtain a sample set of noise values over a noise estimation interval using pairs of like valued samples from the selected received signals; and estimate a noise statistic for the received signal of interest based on the sample set of noise values; wherein the number of received signals selected is based on a desired number of noise values in the sample set of noise values. 18. The mobile station of claim 17, wherein the mobile station selects a given one of the plurality of received signals based on the given received signal having a repeating symbol pattern such that the pairs of like valued samples can be obtained by sampling repeated symbols. 19. The mobile station of claim 17, wherein the mobile station selects a given one of the plurality of received signals based on the given one of the plurality of received signals having a first CDMA spreading gain that is at multiple of a second CDMA spreading gain associated with the received signal of interest. 20. The mobile station of claim 19, wherein the mobile station obtains the pairs of like valued samples from the given one of the plurality of received signals based on despreading the given one of the plurality of received signals using the second CDMA spreading gain. 21. The mobile station of claim 17, wherein the mobile station selects a given one of the plurality of received signals based on a relative power level of the given one of the plurality of received signals. 22. The mobile station of claim 21, wherein the mobile station obtains the pairs of like valued samples from the given one of the plurality of received signals based on generating duplicate sample values from actual sample values obtained from the given one of the plurality of received signals. 23. The mobile station of claim 22, wherein the mobile station includes a signal demodulator and generates the duplicate sample values by modifying hard decision values output by the signal demodulator using one or more channel estimation parameters associated with the given one of the plurality of received signals. 24. The mobile station of claim 17, wherein the mobile station obtains the sample set of noise values over the noise estimation interval by obtaining pairs of like valued samples from each of the plurality of received signals, and subtracting one sample of each pair from the other to obtain the sample set of noise values. 25. The mobile station of claim 17, wherein the received signal of interest comprises a first CDMA signal and the plurality of received signals comprise at least second and third CDMA signals transmitted simultaneously with the first CDMA signal, and wherein the mobile station obtains the sample set of noise values by obtaining a first number of noise values from the second CDMA signal and obtaining a second number of noise values from the third CDMA signal. 26. The mobile station of claim 25, wherein the mobile station obtains an equal number of noise values from the second and third CDMA signals over the noise estimation interval. 27. The mobile station of claim 25, wherein the mobile station determines a signal-to-noise ratio (SNR) for the first CDMA signal using the noise statistic determined from the second and third CDMA signals. 28. The mobile station of claim 27, wherein the first CDMA signal is a traffic channel signal, and at least one of the second and third CDMA signals comprises a messaging channel signal associated with the traffic channel signal, and wherein the mobile station determines the SNR as a traffic channel SNR. 29. The mobile station of claim 28, wherein the mobile station determines the traffic channel SNR based on: determining a signal strength for the traffic channel signal; computing a sample variance of the noise values as the noise statistic; and calculating the traffic channel SNR based on the signal strength and the sample variance. 30. The mobile station of claim 28, wherein the mobile station performs closed-loop power control of the traffic channel signal based on the traffic channel SNR.