Adaptive interference cancellation algorithm using speech mode dependent thresholds
View Patent ↗Adaptive interference cancellation algorithm using speech mode dependent thresholds. A method of processing radio frequency (RF) bursts dependent on a speech mode associated with data contained within the RF burst is presented. Different voice modes, full rate, half rate, and adaptive multi-channel rates each may require different signal to noise ratio (SNR) conditions in order to be successfully processed. To improve the equalization, the SNR associated with the burst is estimated. Based on the SNR or other related conditions, a decision can be made as to whether or not an interference cancellation burst process should be implemented. For example, any one or more of SNR of the signal, a measure of colored noise within the signal, an indication whether the signal being noise limited or interference limited, and a channel profile of the signal may indicate the presence of interference requiring the cancellation of such interference.
1. An apparatus, comprising:
a receiver;
a multi-branch equalizer; and
a mode selection module for:
analyzing at least one characteristic of a signal; and
based on the at least one characteristic, selectively enabling a selected at least one equalizer branch of the multi-branch equalizer for processing the signal thereby generating at least one plurality of soft decisions or disabling all equalizer branches of the multi-branch equalizer from processing the signal and enabling the receiver for processing the signal thereby generating the at least one plurality of soft decisions; and wherein:
at least one equalizer branch of the multi-branch equalizer being trained based upon a predetermined training sequence.
2. The apparatus of claim 1 , wherein:
each equalizer branch of the multi-branch equalizer including a respective plurality of finite impulse response (FIR) filters processing the signal.
3. The apparatus of claim 1 , wherein:
a first equalizer branch of the multi-branch equalizer processing the signal thereby generating a first plurality of soft decisions;
a second equalizer branch of the multi-branch equalizer, after being trained based on the first plurality of soft decisions, processing the signal thereby generating a second plurality of soft decisions.
4. The apparatus of claim 3 , further comprising:
a channel decoder for processing the first plurality of soft decisions thereby generating decoded bits;
a re-encoder for re-encoding the decoded bits thereby generating re-encoded bits; and wherein:
the re-encoded bits being used for training the second equalizer branch of the multi-branch equalizer.
5. The apparatus of claim 4 , further comprising:
a de-interleaver interposed between the multi-branch equalizer and the channel decoder; and
an interleaver interposed between the re-encoder and at least one equalizer branch of the multi-branch equalizer.
6. The apparatus of claim 1 , further comprising:
a derotation block for derotating the signal before the mode selection module analyzing at least one characteristic of the signal.
7. The apparatus of claim 1 , wherein:
the at least one characteristic being a signal to noise ratio (SNR) of the signal, a measure of colored noise within the signal, an indication whether the signal being noise limited or interference limited, or a channel profile of the signal.
8. The apparatus of claim 1 , wherein:
mode selection module:
analyzing a plurality of characteristics of the signal; and
based on the plurality of characteristics, enabling the selected at least one equalizer branch of the multi-branch equalizer for processing the signal thereby generating the at least one plurality of soft decisions; and
the plurality of characteristics of the signal including a signal to noise ratio (SNR) of the signal, a measure of colored noise within the signal, an indication whether the signal being noise limited or interference limited, and a channel profile of the signal.
9. The apparatus of claim 1 , wherein:
based on a comparison of the at least one characteristic with at least one predetermined characteristic, the mode selection module enabling the selected at least one equalizer branch of the multi-branch equalizer for processing the signal thereby generating the at least one plurality of soft decisions.
10. The apparatus of claim 1 , wherein:
the apparatus being implemented within a communication device operable within a wireless communication system.
11. An apparatus, comprising:
a receiver;
a multi-branch equalizer including a first equalizer branch and a second equalizer branch; and
a mode selection module for:
analyzing at least one characteristic of a signal; and
based on the at least one characteristic, selectively:
enabling a selected at least one equalizer branch of the multi-branch equalizer for processing the signal thereby generating at least one plurality of soft decisions; or
disabling all equalizer branches of the multi-branch equalizer from processing the signal and enabling the receiver for processing the signal thereby generating at least one additional plurality of soft decisions; and wherein:
at least one of the first equalizer branch and the second equalizer branch being trained based upon a predetermined training sequence.
12. The apparatus of claim 11 , wherein:
the first equalizer branch processing the signal thereby generating a first plurality of soft decisions;
the second equalizer branch, after being trained based on the first plurality of soft decisions, processing the signal thereby generating a second plurality of soft decisions.
13. The apparatus of claim 12 , further comprising:
a channel decoder for processing the first plurality of soft decisions thereby generating decoded bits;
a re-encoder for re-encoding the decoded bits thereby generating re-encoded bits; and wherein:
the re-encoded bits being used for training the second equalizer branch.
14. The apparatus of claim 13 , further comprising:
a de-interleaver interposed between the multi-branch equalizer and the channel decoder; and
an interleaver interposed between the re-encoder and at least one equalizer branch of the multi-branch equalizer.
15. The apparatus of claim 11 , wherein:
the at least one characteristic being a signal to noise ratio (SNR) of the signal, a measure of colored noise within the signal, an indication whether the signal being noise limited or interference limited, or a channel profile of the signal.
16. A method for operating a communication device, the method comprising:
analyzing at least one characteristic of a signal;
training at least one equalizer branch of a multi-branch equalizer based upon a predetermined training sequence; and
based on the at least one characteristic, selectively enabling a selected at least one equalizer branch of the multi-branch equalizer for processing the signal thereby generating at least one plurality of soft decisions or disabling all equalizer branches of the multi-branch equalizer from processing the signal and enabling a receiver for processing the signal thereby generating the at least one plurality of soft decisions.
17. The method of claim 16 , further comprising:
within one equalizer branch of the multi-branch equalizer that includes a plurality of finite impulse response (FIR) filters, processing the signal using the plurality of FIR filters.
18. The method of claim 16 , further comprising:
operating a first equalizer branch of the multi-branch equalizer for processing the signal thereby generating a first plurality of soft decisions;
operating a second equalizer branch of the multi-branch equalizer, after being trained based on the first plurality of soft decisions, for processing the signal thereby generating a second plurality of soft decisions.
19. The method of claim 16 , wherein:
the at least one characteristic being a signal to noise ratio (SNR) of the signal, a measure of colored noise within the signal, an indication whether the signal being noise limited or interference limited, or a channel profile of the signal.
20. The method of claim 16 , wherein:
the communication device being operable within a wireless communication system.