Techniques for managing interference in multiple channel communications system
An apparatus may include a processor circuit, and a dynamic filter adjustment component for execution on the processor. The dynamic filter adjustment component may identify in a wideband communications signal a set of one or more interferer frequencies for one or more respective interferer channels of a set of communications channels to be filtered, select a kernel filter comprising a low pass filter having a channel width corresponding to a channel of the one or more interferer channels, and generate a co-channel interference (CCI) filter to stop the one or more interferer channels by inverting the kernel filter. Other embodiments are described and claimed.
1. An apparatus, comprising:
a processor circuit; and
a dynamic filter adjustment component for execution on the processor to:
identify in a wideband communications signal a set of one or more interferer frequencies for one or more respective interferer channels of a set of communications channels to be filtered;
select a kernel filter comprising a low pass filter having a channel width corresponding to a channel of the one or more interferer channels; and
generate a co-channel interference (CCI) filter to stop the one or more interferer channels by inverting the kernel filter.
2. The apparatus of claim 1 , the dynamic filter adjustment component for execution on the processor circuit to:
generate one or more N-tap filters by frequency shifting the kernel filter to the one or more interferer frequencies;
form an interferer pass filter by summing the one or more N-tap filters;
subtract the interferer pass filter from a unitary filter I to form the CCI filter; and
apply the CCI filter to the wideband signal.
3. The apparatus of claim 1 , the dynamic filter adjustment component for execution on the processor circuit to generate the kernel filter (KF) by:
generating a high pass filter HPF in a baseband region; and
subtracting the high pass filter from a unitary filter I, wherein KF is given by I-HPF.
4. The apparatus of claim 2 , the interferer pass filter comprising an N-tap filter h(i) and being determined by:
h
(
i
)
=
∑
k
=
1
M
h
0
(
i
)
exp
(
j
2
π
(
i
-
D
)
f
k
T
)
for
i
=
0
,
1
,
2
,
…
,
N
-
1
where M is the number of interferer channels, f k is the center frequency of each interferer, D is filter group delay in samples, and T is the sampling interval.
5. The apparatus of claim 3 , the dynamic filter adjustment component for execution on the processor circuit to filter input (INPUT) of the wideband signal to produce a filtered output signal (OUTPUT) given by
[
Output
]
=
[
I
-
∑
k
=
1
M
(
I
-
HPF
)
frequency_shift
(
k
)
]
[
Input
]
where M is the number of interferer channels.
6. The apparatus of claim 1 , the dynamic filter adjustment component for execution on the processor circuit to prestore the kernel filter in memory.
7. The apparatus of claim 1 , the dynamic filter adjustment component for execution on the processor circuit to:
measure spectral location of the one or more interferer frequencies when the wideband communication signal is received; and
determine filter coefficients for the CCI filter based upon spectral location of the one or more interferer frequencies.
8. The apparatus of claim 1 , the dynamic filter adjustment component for execution on the processor circuit to measure signal-to-noise ratio (SNR) over at least a portion of a frequency range spanned by the wideband frequency range.
9. The apparatus of claim 1 , the kernel filter comprising a product kernel filter generated from two or more prestored kernel filters, the dynamic filter adjustment component for execution on the processor circuit to select the kernel filter by:
selecting two or more prestored kernel filters having a combined bandwidth equal to the channel width of the one or more interferer channels;
shifting frequency of the two or more prestored kernel filters to form two or more shifted kernel filters; and
adding the two or more shifted kernel filters.
10. The apparatus of claim 1 , comprising a cable connector to receive the wideband communications signal comprising a quadrature amplitude modulation signal and orthogonal frequency division multiplexing signal.
11. At least one non-transitory computer-readable storage medium comprising instructions that, when executed, cause a system to:
identify in a wideband communications signal a set of one or more interferer frequencies for one or more respective interferer channels of a set of communications channels to be filtered;
select a kernel filter comprising a low pass filter having a channel width corresponding to a channel of the one or more interferer channels;
generate a co-channel interference (CCI) filter to stop the one or more interferer channels by inverting the kernel filter.
12. The at least one non-transitory computer-readable storage medium of claim 11 comprising instructions that, when executed, cause the system to:
generate one or more N-tap filters by frequency shifting the kernel filter to the one or more frequency ranges;
form an interferer pass filter by summing the one or more N-tap filters;
subtract the pass filter from a unitary filter I to form the CCI filter; and
apply the CCI filter to the wideband signal;
subtract the interferer pass filter from a unitary filter I to form the CCI filter; and
apply the CCI filter to the wideband signal.
13. The at least one non-transitory computer-readable storage medium of claim 11 comprising instructions that, when executed, cause the system to generate the kernel filter (KF) by:
generating a high pass filter HPF in a baseband region; and
subtracting the high pass filter from a unitary filter I, wherein KF is given by I-HPF.
14. The at least one non-transitory computer-readable storage medium of claim 13 comprising instructions that, when executed, cause the system to generate the interferer pass filter as an N-tap filter h(i) and being determined by:
h
(
i
)
=
∑
k
=
1
M
h
0
(
i
)
exp
(
j
2
π
(
i
-
D
)
f
k
T
)
for
i
=
0
,
1
,
2
,
…
,
N
-
1
where M is the number of interferer channels, f k is the frequency of each interferer, D is filter group delay in samples, and T is the sampling interval.
15. The at least one non-transitory computer-readable storage medium of claim 13 comprising instructions that, when executed, cause the system to filter input (INPUT) of the wideband signal to produce a filtered output signal (OUTPUT) given by
[
Output
]
=
[
I
-
∑
k
=
1
M
(
I
-
HPF
)
frequency_shift
(
k
)
]
[
Input
]
where M is the number of interferer channels.
16. The at least one non-transitory computer-readable storage medium of claim 11 comprising instructions that, when executed, cause the system to prestore the kernel filter in memory.
17. The at least one non-transitory computer-readable storage medium of claim 11 comprising instructions that, when executed, cause the system to:
measure spectral location of the one or more interferer frequencies when the wideband communication signal is received; and
determine filter coefficients for the CCI filter based upon spectral location of the one or more interferer frequencies.
18. The at least one non-transitory computer-readable storage medium of claim 11 comprising instructions that, when executed, cause the system to measure signal-to-noise ratio (SNR) over at least a portion of a frequency range spanned by the wideband frequency range.
19. The at least one non-transitory computer-readable storage medium of claim 11 comprising instructions that, when executed, cause the system to select the kernel filter by:
selecting two or more prestored kernel filters having a combined bandwidth equal to the channel width of the one or more interferer channels;
shifting frequency of the two or more prestored kernel filters to form two or more shifted kernel filters; and
adding the two or more shifted kernel filters to form the kernel filter.
20. A computer implemented method, comprising:
identifying in a wideband communications signal a set of one or more interferer frequencies for one or more respective interferer channels of a set of communications channels to be filtered;
selecting a kernel filter comprising a low pass filter having a channel width corresponding to a channel of the one or more interferer channels; and
generating a co-channel interference (CCI) filter to stop the one or more interferer channels by inverting the kernel filter.
21. The computer implemented method of claim 20 , comprising:
generating one or more N-tap filters by frequency shifting the kernel filter to the one or more frequency ranges;
forming an interferer pass filter by summing the one or more N-tap filters;
subtracting the pass filter from a unitary filter I to form the CCI filter; and
applying the CCI filter to the wideband signal.
22. The computer implemented method of claim 20 , the generating the kernel filter (KF) comprising:
generating a high pass filter HPF in a baseband region; and
subtracting the high pass filter from a unitary filter I, wherein KF is given by I-HPF.
23. The computer implemented method of claim 22 , the interferer pass filter comprising an N-tap filter h(i) and being determined by:
h
(
i
)
=
∑
k
=
1
M
h
0
(
i
)
exp
(
j
2
π
(
i
-
D
)
f
k
T
)
for
i
=
0
,
1
,
2
,
…
,
N
-
1
where M is the number of interferer channels, f k is the frequency of each interferer, D is filter group delay in samples, and T is the sampling interval.
24. The computer implemented method of claim 22 , comprising filtering input (INPUT) of the wideband signal to produce a filtered output signal (OUTPUT) given by
[
Output
]
=
[
I
-
∑
k
=
1
M
(
I
-
HPF
)
frequency_shift
(
k
)
]
[
Input
]
where M is the number of interferer channels.
25. The computer implemented method of claim 20 , comprising prestoring the kernel filter in memory.
26. The computer implemented method of claim 20 , comprising:
measuring spectral location of the one or more interferer frequencies when the wideband communication signal is received; and
determining filter coefficients for the CCI filter based upon spectral location of the one or more interferer frequencies.
27. The computer implemented method of claim 20 , comprising measuring signal-to-noise ratio (SNR) over at least a portion of a frequency range spanned by the wideband frequency range.
28. The computer implemented method of claim 20 , the selecting the kernel filter comprising:
selecting two or more prestored kernel filters having a combined bandwidth equal to the channel width of the one or more interferer channels;
shifting frequency of the two or more prestored kernel filters to form two or more shifted kernel filters; and
adding the two or more shifted kernel filters to form the kernel filter.