Reconstruction method of discrete digital signals in noisy overloaded wireless communication systems
A computer-implemented reconstruction method of discrete digital signals in noisy overloaded wireless communication systems that is characterized by a channel matrix of complex coefficients, the method including, receiving the signal from channel by a signal detector, measuring the noise power by a noise power estimator at the receiver, forwarding the detected signal and noise power estimation to a decoder that estimates the transmitted symbol, wherein the estimation of the decoder produces a symbol that could probably have been transmitted it is forwarded to a de-mapper, which outputs the bit estimates corresponding to the estimated transmit signal and the corresponding estimated symbol to a microprocessor for further processing.
1. A computer-implemented reconstruction method of discrete digital signals in noisy overloaded wireless communication systems that is characterized by a channel matrix of complex coefficients, the method including
Receiving the signal from channel by a signal detector;
Measuring the noise power by a noise power estimator at the receiver;
Forwarding the detected signal and noise power estimation to a decoder that estimates the transmitted symbol-(s),
wherein the estimation of the decoder produces a symbol that could have been transmitted and that is forwarded to a de-mapper, which outputs the bit estimates corresponding to the estimated transmit signal and the corresponding estimated symbol to a microprocessor for further processing; and
wherein the decoder uses the noise power estimation explicitly within the decoding process in such a way that it minimizes the effect of noise amplification.
2. The method of claim 1 , wherein minimizing the effect of noise amplification is done by directly considering the noise power measurement in the estimation of the transmit symbol.
3. The method of claim 1 , wherein the minimizing the effect of noise amplification according to the minimization formulation via a first function, a second function, and a third function used to estimate the transmit signal(s)
arg
min
s
∈
ℂ
N
t
y
-
Hs
2
2
+
σ
n
2
s
2
2
+
λ
∑
i
=
1
2
b
s
-
c
i
1
0
wherein:
H is a channel matrix of complex coefficients;
c i is a set of discrete symbols, which form a constellation C of symbols;
N t and N r are dimensions, respectively, of input and output signals;
H∈ N r ×N t is a measurement matrix between the input and output signals, a normalized input symbol vector consisting of elements sampled from a same constellation set ={c 1 , ⋅ ⋅ ⋅ c 2b } of cardinality 2b is described as s=[s 1 , ⋅ ⋅ ⋅ s N t ] T ∈ N t ×1 with b denoting a number of bits per symbol;
n∈ N r ×1 represents an independent and identically distributed circular symmetric complex Additive White Gaussian Noise (AWGN) vector with zero mean and covariance matrix
N
t
ρ
I
N
r
,
where ρ is a fundamental signal-to-noise-ratio (SNR);
y is a received signal vector;
s represents symbol vectors of symbols c i of the constellation ;
N t is a number of transmitter antennas or ports;
λ is a penalty parameter;
σ is a standard deviation of the effective noise at the receiver;
σ 2 is a power or noise variance;
double-vertical lines on both sides means a Frobenius norm of a vector; and
the first function, the second function, and the third function are terms, which are separated by the two “+” signs, in the minimization formulation.
4. The method of claim 3 , wherein the fractional programming algorithm is targeted to find a value of the third function that is lower than the global minimum of the first function.
5. The method of claim 3 , wherein the first function is a Euclidian distance function centered around the received signal's vector.
6. The method of claim 3 , wherein the second function is the product of the estimated noise power and transmit signal power.
7. The method of claim 3 , wherein the third function is a function based on or tightly approximating an l 0 -norm.
8. A receiver of a communication system having a processor, volatile and/or non-volatile memory, at least one interface adapted to receive a signal in a communication channel, wherein the non-volatile memory stores computer program instructions which, when executed by the microprocessor, configure the receiver to implement reconstruction of discrete digital signals in noisy overloaded wireless communication systems that is characterized by a channel matrix of complex coefficients, by performing operations including
Receiving the signal from channel by a signal detector
Measuring the noise power by a noise power estimator at the receiver
Forwarding the detected signal and noise power estimation to a decoder that estimates the transmitted symbol (s),
wherein the estimation of the decoder produces a symbol that could have been transmitted and that is forwarded to a de-mapper, which outputs the bit estimates corresponding to the estimated transmit signal and the corresponding estimated symbol to a microprocessor for further processing; and
wherein the decoder uses the noise power estimation explicitly within the decoding process in such a way that it minimizes the effect of noise amplification.
9. The receiver of claim 8 , wherein minimizing the effect of noise amplification is done by directly considering the noise power measurement in the estimation of the transmit symbol.
10. The receiver of claim 8 , wherein the minimizing the effect of noise amplification according to the minimization formulation via a first function, a second function, a third function used to estimate the transmit signal (s)
arg
min
s
∈
ℂ
N
t
y
-
Hs
2
2
+
σ
n
2
s
2
2
+
λ
∑
i
=
1
2
b
s
-
c
i
1
0
wherein:
H is a channel matrix of complex coefficients;
c i is a set of discrete symbols, which form a constellation C of symbols;
N t and N r are dimensions, respectively, of input and output signals;
H∈ N r ×N t is a measurement matrix between the input and output signals, a normalized input symbol vector consisting of elements sampled from a same constellation set ={c 1 , ⋅ ⋅ ⋅ c 2b } of cardinality 2b is described as s=[s 1 ⋅ ⋅ ⋅ s N t ] T ∈ N t ×1 with b denoting a number of bits per symbol;
n∈ N r ×1 represents an independent and identically distributed circular symmetric complex Additive White Gaussian Noise (AWGN) vector with zero mean and covariance matrix
N
t
ρ
I
N
r
,
where ρ is a fundamental signal-to-noise-ratio (SNR);
y is a received signal vector;
s represents symbol vectors of symbols c i of the constellation C;
N t is a number of transmitter antennas or ports;
λ is a penalty parameter;
σ is a standard deviation of the effective noise at the receiver;
σ 2 is a power or noise variance;
double-vertical lines on both sides means a Frobenius norm of a vector; and
the first function, the second function, and the third function are terms, which are separated by the two “+” signs, in the minimization formulation.
11. The receiver of claim 10 , wherein the fractional programming algorithm is targeted to find a value of the third function that is lower than the global minimum of the first function.
12. The receiver of claim 10 , wherein the first function is a Euclidian distance function centered around the received signal's vector.
13. The receiver of claim 10 , wherein the second function is the product of the estimated noise power and transmit signal power.
14. The receiver of claim 10 , wherein the third function is a function based on or tightly approximating an l 0 -norm.