PUCCH Format 1 signal processing with reduced complexity and robust noise estimation
A network device includes a processor, and receiver circuitry receiving a signal from a plurality of terminal devices, over a physical uplink control channel (PUCCH) format 1 (FMT1). The processor is coupled to the receiver circuitry, and performs processing on the received signal to obtain decoded data and signal-to-noise ratios (SNRs) corresponding to the plurality of terminal devices, and utilizes the decoded data and the SNRs for handling further communications with the plurality of terminal devices. In the processing, the processor obtains, from the received signal, a time domain sequence by performing a transform from a frequency domain into a time domain. The processor extracts, from the time domain sequence, noise blocks and one or more data blocks corresponding to each terminal device among the plurality of terminal devices. The processor further estimates a current noise power value based on the extracted noise blocks and a previous noise power value.
1. A network device, comprising:
receiver circuitry configured to receive a signal from a plurality of terminal devices, the signal received over a physical uplink control channel (PUCCH) format 1 (FMT1); and
a processor coupled to the receiver circuitry, and configured to:
perform processing on the received signal to obtain decoded data and signal-to-noise ratios (SNRs) corresponding to the plurality of terminal devices; and
utilize the decoded data and the SNRs for handling further communications with the plurality of terminal devices,
wherein, in the processing, the processor is configured to:
obtain, from the received signal, a time domain sequence, by performing a transform from a frequency domain into a time domain;
extract, from the time domain sequence,
noise blocks, and
one or more data blocks corresponding to each terminal device among the plurality of terminal devices; and
estimate a current noise power value based on
the extracted noise blocks, and
a previous noise power value.
2. The network device of claim 1 , wherein
the processor is configured to, using a base sequence, obtain a demodulated signal sequence from the received signal, and
perform, on the demodulated signal sequence, the transform from the frequency domain into the time domain to obtain the time domain sequence.
3. The network device of claim 1 , wherein
the transform from the frequency domain into the time domain comprises an Inverse Discrete Fourier Transform (IDFT).
4. The network device of claim 1 , wherein
the processor is configured to extract, from the time domain sequence and based on an initial cyclic shift that is unique for each terminal device among the plurality of terminal devices, the one or more data blocks corresponding to the terminal device.
5. The network device of claim 4 , wherein
the processor is further configured to extract, from the time domain sequence and based on the initial cyclic shift that is unique for each terminal device among the plurality of terminal devices, one or more demodulation reference signal (DMRS) blocks corresponding to the terminal device.
6. The network device of claim 5 , wherein
in the processing, the processor is further configured to, for each terminal device among the plurality of terminal devices,
remove orthogonal cover code (OCC) from the one or more data blocks and the one or more DMRS blocks, to correspondingly obtain OCC-removed data and OCC-removed DMRS.
7. The network device of claim 6 , wherein
in the processing, the processor is further configured to, for each terminal device among the plurality of terminal devices,
obtain decoded data, based on the OCC-removed data and OCC-removed DMRS of the terminal device.
8. The network device of claim 7 , wherein
in the processing, the processor is further configured to determine the SNR of each terminal device among the plurality of terminal devices, based on
the current noise power value, and
the OCC-removed DMRS of the terminal device.
9. The network device of claim 1 , wherein
the processor is configured to extract, from the time domain sequence, the noise blocks based on a reserved initial cyclic shift that is not used by, or allotted to, any terminal device among the plurality of terminal devices.
10. The network device of claim 1 , wherein
the processor is further configured to, for each terminal device among the plurality of terminal devices,
in response to the SNR of the terminal device being equal to or lower than a predetermined threshold, determine that the received signal includes no signal from the terminal device; and
in response to the SNR of the terminal device being higher than the predetermined threshold, send the decoded data of the terminal device to at least one higher layer in a protocol stack of the network device.
11. A non-transitory, tangible computer readable storage medium storing a computer program that, when executed by a processor, causes the processor to:
perform an Inverse Discrete Fourier Transform (IDFT) transform to obtain a time domain sequence from each received signal among a plurality of received signals, the plurality of signals correspondingly received at a plurality of antennas from a plurality of terminal devices over a physical uplink control channel (PUCCH) format 1 (FMT1);
extract noise blocks from the time domain sequence;
perform an Infinite Impulse Response (IIR) estimation to obtain a current noise power value from the extracted noise blocks; and
for each terminal device among the plurality of terminal devices,
extract, from the time domain sequence, one or more data blocks corresponding to the terminal device;
obtain decoded data of the terminal device, based on the one or more data blocks;
determine a signal-to-noise ratio (SNR) of the terminal device based on the current noise power value, and
utilize the decoded data and the SNR for handling further communications with the terminal device.
12. The storage medium of claim 11 , wherein the computer program, when executed by the processor, further causes the processor to:
obtain a demodulated signal sequence from the received signal; and
perform the IDFT on the demodulated signal sequence to obtain the time domain sequence.
13. The storage medium of claim 12 , wherein the computer program, when executed by the processor, further causes the processor to, for each terminal device among the plurality of terminal devices:
extract, from the time domain sequence, one or more demodulation reference signal (DMRS) blocks corresponding to the terminal device;
determine the SNR of the terminal device, based on the current noise power value and the DMRS blocks;
obtain the decoded data of the terminal device, based on the one or more data blocks and the one or more DMRS blocks;
in response to the SNR of the terminal device being equal to or lower than a predetermined threshold, determine that the received signals include no signal from the terminal device; and
in response to the SNR of the terminal device being higher than the predetermined threshold, send the decoded data of the terminal device to at least one higher layer in a protocol stack.
14. The storage medium of claim 11 , wherein the computer program, when executed by the processor, further causes the processor to:
perform a de-cyclic shift, using following Equation 1:
dePrbsSeq
(
ant
,
k
,
l
)
=
Y
(
ant
,
k
,
l
)
*
conj
(
r
_
u
,
v
(
n
)
)
,
(
Equation
1
)
where
dePrbsSeq(ant, k, l) represents a demodulated signal sequence obtained after the de-cyclic shift,
ant is an antenna index of a corresponding antenna receiving the received signal,
k is a frequency index,
l is a time index,
Y(ant, k, l) is the received signal,
conj is a complex conjugation operator, and
r u,v (n) is a base sequence; and
perform the IDFT on the demodulated signal sequence to obtain the time domain sequence, using following Equation 2:
idftOut
(
ant
,
:
,
l
)
=
idft
(
dePrbsSeq
(
ant
,
:
,
l
)
)
,
(
Equation
2
)
where
“:” includes all values of k from 0 to K, and K is a maximum value for k,
idftOut(ant,:,l) is the time domain sequence for the corresponding antenna at symbol l, and
idft is the IDFT.
15. The storage medium of claim 14 , wherein the computer program, when executed by the processor, further causes the processor to, for each terminal device among the plurality of terminal devices:
extract, from the time domain sequence, the one or more data blocks corresponding to the terminal device, using following Equation 3:
tapLocData
(
l
data
)
=
N
sc
RB
-
(
n
cs
(
n
s
,
l
)
+
m
0
)
,
(
Equation
3
)
tapExtractsData
(
ant
,
l
data
)
=
idftOut
(
ant
,
tapLocData
(
l
)
,
l
)
;
and
extract, from the time domain sequence, one or more demodulation reference signal (DMRS) blocks corresponding to the terminal device, using following Equation 4:
tapLocDmrs
(
l
dmrs
)
=
N
sc
RB
-
(
n
cs
(
n
s
,
l
)
+
m
0
)
,
(
Equation
4
)
tapExtractsDmrs
(
ant
,
l
dmrs
)
=
idftOut
(
ant
,
tapLocDmrs
(
l
)
,
l
)
,
where
NRB sc RB is a resource block size,
n cs (n s , l) is a cyclic shift value,
m 0 is an initial cyclic shift that is unique for the terminal device,
tapLocData(l data ) is a location of a data block in a data symbol l data in the time domain sequence,
idftOut(ant, tapLocData(l),l) is the data block at tapLocData(l data ),
tapExtractsData(ant, l data ) is the extracted data block,
tapLocDmrs(l dmrs ) is a location of a DMRS block in a DMRS symbol l dmrs in the time domain sequence,
idftOut(ant, tapLocDmrs(l),l) is the DMRS block at tapLocDmrs(l dmrs ), and
tapExtractsDmrs(ant, l dmrs ) is the extracted DMRS block.
16. The storage medium of claim 15 , wherein the computer program, when executed by the processor, further causes the processor to, for each terminal device among the plurality of terminal devices:
remove orthogonal cover code (OCC) from the one or more data blocks and the one or more DMRS blocks, to correspondingly obtain OCC-removed data and OCC-removed DMRS, using following Equation 5 and Equation 6:
deOccData
(
ant
)
=
mean
(
tapExtractsData
(
ant
,
l
data
)
*
conj
(
w
(
l
data
)
)
)
,
(
Equation
5
)
deOccDmrs
(
ant
)
=
mean
(
tapExtractsDmrs
(
ant
,
l
dmrs
)
*
conj
(
w
(
l
dmrs
)
)
)
,
(
Equation
6
)
where
w(l data ) is the OCC corresponding to the extracted data block tapExtractsData(ant, l data ),
deOccData(ant) is the OCC-removed data which is a mean of tapExtractsData(ant, l data )*conj(w(l data )) across all data symbols in the time domain sequence,
w(l dmrs ) is the OCC corresponding to the extracted DMRS block tapExtractsDmrs(ant, l dmrs ), and
deOccDmrs(ant) is the OCC-removed DMRS which is a mean of tapExtractsDmrs(ant, l dmrs )*conj(w(l dmrs )) across all DMRS symbols in the time domain sequence.
17. The storage medium of claim 16 , wherein the computer program, when executed by the processor, further causes the processor to:
extract, from the time domain sequence, the noise blocks, using Equation 3 with m 0 being a reserved initial cyclic shift that is not used by, or allotted to, any terminal device among the plurality of terminal devices;
determine an instant noise power value, using following Equation 7.1:
instNoisePwr
=
mean
(
abs
(
noiseTapExtracts
(
ant
,
l
)
)
2
)
,
(
Equation
7.1
)
where
noiseTapExtracts(ant, l) is the noise block extracted from the time domain sequence at symbol l, and
instNoisePwr is the instant noise power value, which is a mean of abs(noiseTapExtracts(ant, l)) 2 across all symbols in the time domain sequence for each antenna and also across all of the plurality of antennas;
determine the current noise power value, using following Equation 7.2:
iirAvgNoisePwr
=
(
β
*
iirAvgNoisePwr
p
)
+
(
(
1
-
β
)
*
instNoisePwr
)
,
(
Equation
7.2
)
where
iir AvgNoisePwr is the current noise power value,
iir AvgNoisePwr p is a previous noise power value, and
β is an IIR weight, where 0<β<1; and
for each terminal device among the plurality of terminal devices,
determine signal power of the terminal device, using following Equation 8:
signalPwr
=
mean
(
abs
(
deOccDmrs
(
ant
)
)
2
)
;
(
Equation
8
)
and
determine the SNR of the terminal device, using following Equation 9:
snr
dB
=
10
*
log
10
(
signalPwr
iirAvgNoisePwr
)
,
(
Equation
9
)
where
signalPwr is the signal power of the terminal device which is a mean of abs(deOccDmrs(ant)) 2 across all of the plurality of antennas, and
snr dB is the SNR of the terminal device.
18. The storage medium of claim 17 , wherein the computer program, when executed by the processor, further causes the processor to, for each terminal device among the plurality of terminal devices:
perform data equalization and data decoding, using following Equation 10 and Equation 11:
decDataSymb
(
ant
)
=
deOccData
(
ant
)
*
conj
(
deOccDmrs
(
ant
)
)
,
(
Equation
10
)
decData
=
mean
(
decDataSymb
)
,
(
Equation
11
)
where
decDataSymb(ant) is decoded data of the terminal device obtained from the received signal at the corresponding antenna, and
decData is the decoded data of the terminal device which is a mean of decDataSymb(ant) across all of the plurality of antennas.
19. The storage medium of claim 18 , wherein the computer program, when executed by the processor, further causes the processor to, for each terminal device among the plurality of terminal devices:
in response to the SNR of the terminal device being equal to or lower than a predetermined threshold, determine that the received signals include no signal from the terminal device; and
in response to the SNR of the terminal device being higher than the predetermined threshold, send the decoded data of the terminal device to at least one higher layer in a protocol stack.
20. A method performed at least in part by a processor, the method comprising:
obtaining, using a base sequence, a demodulated signal sequence from a signal received over a physical uplink control channel (PUCCH) format 1 (FMT1);
performing an Inverse Discrete Fourier Transform (IDFT) on the demodulated signal sequence to obtain a time domain sequence;
extracting noise blocks from the time domain sequence and based on a reserved initial cyclic shift that is not used by, or allotted to, any terminal device;
performing an Infinite Impulse Response (IIR) estimation to obtain a current noise power value from the extracted noise blocks;
extracting, from the time domain sequence and based on an initial cyclic shift that is unique for a terminal device, one or more data blocks and one or more demodulation reference signal (DMRS) blocks corresponding to the terminal device;
removing orthogonal cover code (OCC) from the one or more data blocks and the one or more DMRS blocks, to correspondingly obtain OCC-removed data and OCC-removed DMRS;
obtaining decoded data, based on the OCC-removed data and OCC-removed DMRS of the terminal device;
determining a signal-to-noise ratio (SNR) of the terminal device based on the current noise power value and the OCC-removed DMRS of the terminal device; and
utilizing the decoded data and the SNR for handling further communications with the terminal device.