PUCCH FORMAT 0 SIGNAL PROCESSING WITH REDUCED COMPLEXITY AND ROBUST NOISE ESTIMATION
A network device includes receiver and a processor. The receiver receives a signal from a group of terminal devices, over a physical uplink control channel (PUCCH) Format 0 (FMT0). The processor is coupled to the receiver, performs processing on the received signal to detect payloads and obtain SNRs corresponding to the terminal devices in the group, and utilizes the detected payloads and the SNRs for handling further communications with the terminal devices. In the processing, the processor obtains a time domain sequence from the received signal by performing a transform from a frequency domain into a time domain, determines a plurality of correlation power values from the time domain sequence, extracts, from the plurality of correlation power values, a maximum correlation power value corresponding to each terminal device, and determines a current noise power value for SNR based on an instant noise power value, and a previous noise power value.
1 . A network device, comprising:
receiver circuitry configured to receive a signal from a group of terminal devices, the signal received over a physical uplink control channel (PUCCH) Format 0 (FMT0); and
a processor coupled to the receiver circuitry, and configured to:
perform processing on the received signal to detect payloads and obtain signal-to-noise ratios (SNRs) corresponding to the terminal devices in the group; and
utilize the detected payloads and the SNRs for handling further communications with the terminal devices in the group,
wherein, in the processing, the processor is configured to:
obtain a time domain sequence from the received signal by performing a transform from a frequency domain into a time domain;
determine a plurality of correlation power values from the time domain sequence;
extract, from the plurality of correlation power values, a maximum correlation power value corresponding to each terminal device among the terminal devices in the group; and
determine a current noise power value for SNR determination based on
an instant noise power value, and
a previous noise power value.
2 . The network device of claim 1 , wherein
in the processing, the processor is configured to:
perform grouping of a plurality of terminal devices into a plurality of groups,
the plurality of groups includes the group of terminal devices, and
each group among the plurality of groups includes terminal devices of a same payload type among a plurality of payload types.
3 . The network device of claim 2 , wherein
the plurality of payload types includes:
Scheduling Request (SR) information and no hybrid automatic repeat request (HARQ) bits,
1 HARQ bit and no SR information,
2 HARQ bits and no SR information,
1 HARQ bit and SR information, and
2 HARQ bits and SR information.
4 . The network device of claim 1 , wherein
the transform from the frequency domain into the time domain comprises an Inverse Discrete Fourier Transform (IDFT).
5 . The network device of claim 1 , wherein
in the processing, the processor is configured to:
determine each correlation power value in the plurality of correlation power values from a corresponding block in the time domain sequence.
6 . The network device of claim 1 , wherein
in the processing and for each terminal device in the group, the processor is configured to:
extract, from the plurality of correlation power values and based on an initial cyclic shift that is unique to the terminal device, a set of correlation power values corresponding to the terminal device.
7 . The network device of claim 6 , wherein
in the processing and for each terminal device in the group, the processor is configured to:
determine a maximum in the set of correlation power values corresponding to the terminal device as the maximum correlation power value corresponding to the terminal device, and
detect the payload of the terminal device based on an index corresponding to the maximum correlation power value corresponding to the terminal device.
8 . The network device of claim 7 , wherein
in the processing, the processor is configured to:
determine the instant noise power value, based on correlation power values which have been extracted for the terminal devices in the group and which are other than the maximum correlation power values corresponding to the terminal devices in the group; and
determine the SNR of each terminal device in the group, based on the current noise power value and the maximum correlation power value corresponding to the terminal device.
9 . The network device of claim 1 , wherein
in the processing and for each terminal device in the group, the processor is configured to:
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 detected payload of the terminal device to at least one higher layer in a protocol stack of the network device.
10 . 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 group of terminal devices over a physical uplink control channel (PUCCH) Format 0 (FMT0);
determine a plurality of correlation power values from the time domain sequence;
perform an Infinite Impulse Response (IIR) estimation to obtain a current noise power value; and
for each terminal device in the group of terminal devices,
extract, from the plurality of correlation power values, a maximum correlation power value corresponding to the terminal device,
detect a payload of the terminal device based on an index corresponding to the maximum correlation power value,
determine a signal-to-noise ratio (SNR) of the terminal device based on the current noise power value, and
utilize the detected payload and the SNR for handling further communications with the terminal device.
11 . The storage medium of claim 10 , wherein the computer program, when executed by the processor, further causes the processor to:
perform grouping of a plurality of terminal devices into a plurality of groups,
the plurality of groups includes the group of terminal devices, and
each group among the plurality of groups includes terminal devices of a same payload type among a plurality of payload types.
12 . The storage medium of claim 10 , wherein the computer program, when executed by the processor, further causes the processor to:
remove a base sequence from the received signal to obtain a base-sequence-removed signal sequence, 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 the base-sequence-removed signal sequence,
ant represents an antenna index of a corresponding antenna receiving the received signal,
k represents a subcarrier index,
l represents a symbol index,
Y(ant, k, l) represents the received signal,
conj represents a complex conjugation operator, and
r u,v (n) represents the base sequence.
13 . The storage medium of claim 12 , wherein the computer program, when executed by the processor, further causes the processor to:
perform the IDFT on the base-sequence-removed 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 represents a maximum value for k,
idftOut(ant, :, l) represents the time domain sequence for the corresponding antenna at symbol l, and
idft represents the IDFT.
14 . The storage medium of claim 13 , wherein the computer program, when executed by the processor, further causes the processor to:
determine correlation power, using following Equation 3:
Corr
Power
(
ant
,
:
,
l
)
=
[
abs
(
idftOut
(
ant
,
:
,
l
)
)
]
2
,
(
Equation
3
)
and
combine the correlation power across the plurality of antennas to obtain the plurality of correlation power values, using following Equation 4:
Corr
PowerPerTone
(
:
,
l
)
=
(
1
numAnt
)
∑
antIdx
=
1
n
u
m
A
n
t
Corr
Power
(
ant
,
:
,
l
)
,
(
Equation
4
)
where
CorrPower(ant, :, l) represents the correlation power for the corresponding antenna at symbol l,
CorrPowerPerTone(:, l) represents the combined correlation power across the plurality of antennas at symbol l,
numAnt represents a number of antennas in the plurality of antennas, and
antIdx represents an antenna index.
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 in the group:
extract, from the plurality of correlation power values and based on an initial cyclic shift that is unique to the terminal device, a set of correlation power values corresponding to the terminal device, using following Equations 5-7:
tapLoc
(
m
cs
,
l
)
=
(
N
sc
RB
-
α
(
m
cs
,
l
)
)
mod
N
sc
RB
,
(
Equation
5
)
tapExtractData
(
m
cs
,
l
)
=
Corr
PowerPerTone
(
tapLoc
(
m
cs
,
l
)
,
l
)
,
(
Equation
6
)
tapExtractDataPerHypo
(
m
cs
)
=
(
1
numSym
)
∑
symIdx
=
1
numSym
tapExtractData
(
m
cs
,
l
)
,
(
Equation
7
)
where
α(m cs , l)=(m 0 +m cs +n cs (n s , l+l′)mod N sc RB ,
N sc RB represents a number of subcarriers per resource block,
m 0 represents the initial cyclic shift that is unique for the terminal device,
m cs represents hypothesis indices for the terminal device,
n cs (n s , l+l′) represents a cyclic shift value,
tapLoc(m cs , l) represents one or more locations of one or more correlation power values to be extracted at symbol l in accordance with m cs ,
tapExtractData(m cs , l) represents correlation power values extracted at symbol l in accordance with the hypothesis indices m cs ,
tapExtractDataPerHypo(m cs ) represents the set of correlation power values corresponding to the terminal device,
numSym represents a number of symbols in the PUCCH FMT0, and
symIdx represents a symbol index.
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 in the group:
determine, based on the set of correlation power values, the maximum correlation power value corresponding to the terminal device, using following Equation 8:
max
CorrelationPower
=
max
(
tapExtraDataPerHypo
(
m
cs
)
)
,
(
Equation
8
)
determine the index corresponding to the maximum correlation power value, using following Equation 9:
max
CorrelationPowerIdx
=
Idx
(
max
(
tapExtraDataPerHypo
(
m
cs
)
)
)
,
(
Equation
9
)
where
maxCorrelationPower represents the maximum correlation power value corresponding to the terminal device, and
Idx represents a function that gives the index corresponding to the maximum correlation power value.
17 . The storage medium of claim 16 , wherein the computer program, when executed by the processor, further causes the processor to:
determine an instant noise power value using following Equation 10.1:
instNoisePwr
=
(
1
numNoiseCycShifts
*
numSym
)
∑
numS
y
m
symIdx
=
1
∑
noiseTapIdx
=
1
numN
o
i
s
eCycShifts
Corr
PowerPerTone
(
noiseTapIdx
,
symIdx
)
,
(
Equation
10.1
)
and
determine the current noise power value, using following Equation 10.2:
iirAvgNoisePwr
=
(
β
*
iirAvgNoisePwr
p
)
+
(
(
1
-
β
)
*
instNoisePwr
)
,
(
Equation
10.2
)
where
instNoisePwr represents the instant noise power value,
numNoiseCycShifts represents one or more reserved cyclic shifts,
noiseTapIdx represents one or more locations of one or more correlation power values corresponding to noise to be extracted,
iirAvgNoisePwr represents the current noise power value,
iirAvgNoisePwr p represents a previous noise power value, and
β is an IIR weight, where 0<β<1.
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 in the group:
determine the SNR of the terminal device, using following Equation 11:
s
n
r
dB
=
1
0
*
log
1
0
(
max
C
o
r
r
e
l
a
t
i
o
n
P
o
w
e
r
i
i
r
A
v
g
N
o
i
s
e
P
w
r
)
,
(
Equation
11
)
where snr dB is the SNR of the terminal device.
19 . The storage medium of claim 10 , wherein the computer program, when executed by the processor, further causes the processor to, for each terminal device in the group:
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 detected payload 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:
grouping of a plurality of terminal devices into a plurality of groups each including terminal devices of a same payload type among a plurality of payload types of a physical uplink control channel (PUCCH) Format 0 (FMT0);
performing a transform from a frequency domain into a time domain to obtain a time domain sequence from each received signal among a plurality of received signals correspondingly received at a plurality of antennas from the group of terminal devices over the PUCCH FMT0;
determining correlation power from the time domain sequence corresponding to each antenna among the plurality of antennas;
combining the correlation power across the plurality of antennas, to obtain a plurality of correlation power values;
performing an Infinite Impulse Response (IIR) estimation to obtain a current noise power value; and
for each terminal device in each group among the plurality of groups,
extracting, from the plurality of correlation power values and based on an initial cyclic shift that is unique to the terminal device, a set of correlation power values corresponding to the terminal device,
determining, from the set of correlation power values, a maximum correlation power value corresponding to the terminal device,
detecting a payload of the terminal device based on an index corresponding to the maximum correlation power value,
determining a signal-to-noise ratio (SNR) of the terminal device based on the current noise power value and the maximum correlation power value corresponding to the terminal device; and
utilizing the detected payload and the SNR for handling further communications with the terminal device,
wherein the IIR estimation comprises determining an instant noise power value based on correlation power values which have been extracted for the terminal devices in the group and which are other than maximum correlation power values corresponding to the terminal devices in the group.