CN101908935B - System for estimating signal-to-noise ratio of signal in multiple carrier system - Google Patents

Abstract

The invention provides a system for estimating the signal-to-noise ratio of a signal in a multiple carrier system. The invention provides the system for estimating the signal-to-noise ratio of the signal based on a blind transmit parameter signaling (TPS) or a pilot signal in the multiple carrier system. The system of the invention comprises a phase rotation device, an energy estimation device, a channel gain calculation device, a selection average device, a combination and calculation device and a dB value conversion device. By the invention, the signal-to-noise ratio of the signal can be estimated to correct a communication system to be in a better condition without checking up the contents of the TPS or the pilot signal in advance.

Description

The estimating system that is used for the Signal-to-Noise of multicarrier system

Technical field

The present invention relates to the technical field of signal transmission, espespecially a kind of estimating system of the Signal-to-Noise for multicarrier system.

Background technology

Efficient and accurate Signal-to-Noise (SNR) estimation is indispensable in communication system.Especially comprising multicarrier (Multi-carrier) system as leading take OFDM or TDS-OFDM, when it works among the multipath fading channel (Multipath fading channels), more need efficient and accurate Signal-to-Noise information to improve system effectiveness.

The people such as Xu were in IEEE 61st Vehicular Technology paper that Conference carries in 2005: in " A Novel SNR Estimation Algorithm for OFDM ", disclosed previous Signal-to-Noise estimating and measuring method, and a second order Signal-to-Noise estimating and measuring method proposed according to this, the method is according to the model of Jakes, and is applicable to fast in the multipath fading channel environment.Yet it only estimates the Signal-to-Noise on each subcarrier, but not for whole ofdm system.

The people such as Athanasios were in ICACT 7th International Conference onAdvanced Communication paper that Technology carries in 2005: in " BPSK SNR estimationalgorithm for HIPERLAN/2 transceiver in AWGN channels ", disclosed a Signal-to-Noise estimating and measuring method in high performance radio local area network (HIPERLAN).Yet it only considers AWGN (Additive white Gaussian noise, additive white Gaussian noise) channel, but not more near the multi-path channel of actual transmissions.Therefore condition and the imperfection considered of existing Signal-to-Noise (SNR) estimation technology, and still have shortcomings and necessity of being improved is arranged.

Summary of the invention

Purpose of the present invention mainly is to provide a kind of estimating system of the Signal-to-Noise for multicarrier system.It is applicable to be operated in comprising take OFDM or TDS-OFDM as main multicarrier (Multi-carrier) system among the multipath fading channel.

According to an aspect of of the present present invention, the present invention proposes a kind of estimating system of the Signal-to-Noise for multicarrier system, and does not need to detect in advance the content of blind transmission parameter signalling or index signal.It comprises phase rotating device, energy estimating apparatus, channel gain calculation element, selects equilibration device, reaches combination and calculation element.This phase rotating device will receive quadrature amplitude modulation (Quadrature Amplitude Modulation, QAM) mark signal (hereinafter to be referred as the qam symbol signal) and channel estimating signal carry out the phase rotating operation, to produce rotation mark signal and rotation channel estimating signal.This energy estimating apparatus is connected in this phase rotating device and comprises a plurality of sub-energy estimating apparatus, estimates this rotation qam symbol signal is carried out energy in each subcarrier, thereby produces signal energy signal and noise energy signal.This channel gain calculation element is connected in this phase rotating device, according to this rotation channel estimating signal, and produces sub-carrier channels gain signal and average channel gain signal.This selection equilibration device is connected to this energy estimating apparatus and this channel gain calculation element, according to criterion signal, this signal energy signal, this noise energy signal, and this sub-carrier channels gain signal, select and produce average signal power set, ensemble average noise power, and average channel gain gather.This combination and calculation element are connected in this selection equilibration device and this channel gain calculation element, gather, reach this average channel gain signal according to this criterion signal, this average signal power set, this ensemble average noise power, this average channel gain, to produce the estimating signal signal to noise ratio.

Description of drawings

Fig. 1 is the estimating system of a kind of Signal-to-Noise for multicarrier system of the present invention, and it is applicable to working in comprising take OFDM or TDS-OFDM as main multicarrier system among the multipath fading channel.

Fig. 2 is the calcspar of sub-energy estimating apparatus of the present invention.

Fig. 3 is the calcspar of another embodiment of sub-energy estimating apparatus of the present invention.

Fig. 4 is the calcspar of channel gain calculation element of the present invention.

Fig. 5 is the calcspar of this selection equilibration device of the present invention.

Fig. 6 is the calcspar of this candidate searcher of the present invention.

Fig. 7 is the calcspar of this combination of the present invention and calculation element.

Fig. 8 is the analog result schematic diagram of estimating system of the Signal-to-Noise of the blind transmission parameter signalling for digital ground multimedia broadcast of the present invention or index signal.

Fig. 9 is another analog result schematic diagram of the estimating system of the Signal-to-Noise for multicarrier system of the present invention.

Figure 10 is the schematic diagram of the various parameters of SARFT-8 multi-path channel.

The main element symbol description

Estimating system 100 phase rotating devices 110

Energy estimating apparatus 120 channel gain calculation elements 130

Select equilibration device 140 combination and calculation elements 150

DB value conversion equipment 160

Sub-energy estimating apparatus 121 deferred mounts 210

Get complex values device 215,220 multipliers 225,230

Get real number value device 235 subtracters 240

Buffer 250 adding up devices 245,255

Get complex values device 310,360 adding up devices 320,340

Multiplier 330,370 subtracters 380

Buffer 350

Buffer 410 first adding up devices 420

The first multiplier 430 first choice devices 440

The second adding up device 450

The 3rd adding up device 510 candidate searchers 520

The second choice device 530

Candidate selecting device 610 number calculation elements 620

The first calculation element 710 second calculation elements 720

The 3rd calculation element 730 the 3rd choice device 740

Embodiment

Fig. 1 is the calcspar of the estimating system 100 of a kind of Signal-to-Noise for multicarrier system of the present invention, and it is applicable to working in comprising take OFDM or TDS-OFDM as main multicarrier system among the multipath fading channel.The required functions such as synchronous and channel estimating of this estimating system are all supposed can to finish in advance, and it is not comprised in the discussion scope of the present invention.

This estimating system 100 comprises phase rotating device 110, energy estimating apparatus 120, channel gain calculation element 130, selects equilibration device 140, combination and calculation element 150, reaches dB value conversion equipment 160.

Make i represent the index (index) of code frame (frame), k represents the index of subcarrier (sub-carrier).Then this phase rotating device 110 is with the qam symbol signal { Y that receives _{I, k}And the channel estimating signal

Carry out the phase rotating operation, to produce rotation qam symbol signal

And rotation channel estimating signal

Order $H_{i,k}=\left|H_{i,k}\right|\·e^{j\∠H_{i,k}},$ And suppose perfect channel estimating so that ${\hat{H}}_{i,k}=H_{i,k},$ 110 pairs of qam symbol signals of this phase rotating device { Y then _{I, k}And the channel estimating signal Rotate respectively negative ∠ H _{I, k}Angle, and produce this rotation qam symbol signal

And this rotation channel estimating signal

This rotation qam symbol signal

Available following formula represents:

${\tilde{Y}}_{i,k}=Y_{i,k}\·e^{-j\∠H_{i,k}},$

This rotation channel estimating signal

Available following formula represents:

${\tilde{H}}_{i,k}=H_{i,k}\·e^{-j\∠H_{i,k}}=\left|H_{i,k}\right|,$

Make that n is time domain qam symbol sequence { y _{I, n}Index.{ Y then _{I, k}{ y _{I, n}Represent sequence through the frequency domain after the FFT computing.

This energy estimating apparatus 120 is connected in this phase rotating device 110 and comprises N _TPSIndividual sub-energy estimating apparatus 121 is to rotate the qam symbol signal to this

In each subcarrier, carry out the energy estimation, and produce signal energy signal S ^TAnd noise energy signal N ^T

Fig. 2 is the calcspar of sub-energy estimating apparatus 121 of the present invention, and wherein, each sub-energy estimating apparatus 121 is relevance energy estimating apparatus, and it receives this rotation qam symbol signal

Frequency domain signal

And the signal energy signal S on the generation subcarrier _kAnd noise energy signal N _kAs shown in Figure 2, this sub-energy estimating apparatus 121 comprises deferred mount 210, gets complex values device 215,220, multiplier 225,230, gets real number value device 235, subtracter 240, buffer 250, and adding up device 245,255.

This deferred mount 210 receives this frequency domain signal And kept in.This is got complex values device 215 and is connected to this deferred mount 210, and so that its temporary signal is got complex values, afterwards, this multiplier 225 will be got signal and this frequency domain signal after the complex values

Multiply each other, get real number and produce signal S through getting real number value device 235 again _{I, k}

This gets 220 pairs of these frequency domain signal of complex values device

After getting complex values, recycling multiplier 230 and this frequency domain signal

Multiply each other, and produce signal P _{I, k}, signal P _{I, k}Can be considered the gross energy on k subcarrier, and signal S _{I, k}Can be considered the signal energy on k subcarrier.So as signal P _{I, k}Utilize subtracter 240 subtraction signal S _{I, k}The rear signal N that produces _{I, k}Can be considered k the noise energy on the subcarrier.

The cumulative letter frame number N of these buffer 250 temporary wishs _s, this adding up device 245,255 is respectively to signal S _{I, k}And signal N _{I, k}Cumulative, and produce this signal energy signal S _kAnd noise energy signal N _k, this signal energy signal S _kAnd noise energy signal N _kCorrespond to k subcarrier.

This energy estimating apparatus 120 has N _TPSIndividual sub-energy estimating apparatus 121, each sub-energy estimating apparatus 121 output signal energy signal S _kAnd noise energy signal N _kSet be this signal energy signal S ^TAnd this noise energy signal N ^T

Fig. 3 is the calcspar of another embodiment of sub-energy estimating apparatus 121 of the present invention, and wherein, each sub-energy estimating apparatus 121 is time average energy estimating apparatus, and it receives this rotation qam symbol signal

Frequency domain signal And the signal energy signal S on the generation subcarrier _kAnd noise energy signal N _kAs shown in Figure 3, this sub-energy estimating apparatus 121 comprises and gets complex values device 310,360, adding up device 320,340, multiplier 330,370, subtracter 380, and buffer 350.

This is got complex values device 310 and receives this frequency domain signal

And get complex values, afterwards, this multiplier 330 will be got signal and this frequency domain signal after the complex values

Multiply each other, and produce signal P _{I, k}, signal P _{I, k}Can be considered the gross energy on k subcarrier.The cumulative letter frame number N of these buffer 350 temporary wishs _s, 340 couples of signal P of this adding up device _{I, k}Cumulative, and produce this signal P _k

340 pairs of these frequency domain signal of this adding up device

Cumulative, this is got complex values device 360 and is connected to this adding up device 340, so that these adding up device 340 output signals are got plural number.Use this multiplier 370 to be connected to this adding up device 340 and this gets complex values device 360, multiply each other with output signal and this output signal of getting complex values device 360 to this adding up device 340, and produce this signal energy signal S _kThis subtracter 380 is with this signal P _kDeduct this signal energy signal S _kAnd produce this noise energy signal N _k

This energy estimating apparatus 120 has N _TPSIndividual sub-energy estimating apparatus 121, each sub-energy estimating apparatus 121 output signal energy signal S _kAnd noise energy signal N _kSet be this signal energy signal S ^TAnd this noise energy signal N ^T

This channel gain calculation element 130 is connected in this phase rotating device 110, according to this rotation channel estimating signal

And generation sub-carrier channels gain signal P _H ^T, and average channel gain signal P _H

Fig. 4 is the calcspar of channel gain calculation element 130 of the present invention, and this channel gain calculation element 130 comprises buffer 410, the first adding up device 420, the first multiplier 430, the first choice device 440, reaches the second adding up device 450.

This buffer 410 stores the number N of figure frame _FThis first adding up device 420 is connected to this buffer 410 and this phase rotating device 110, so that this is rotated the channel estimating signal

Carry out accumulating operation, and produce cumulative rotation channel estimating signal

This first multiplier 430 is connected to this first adding up device 420, with the rotation channel estimating signal that should add up

Multiply each other, to produce k sub-carrier channels gain

This first choice device 440 is connected to this first multiplier 430, and channel gain corresponding to (TPS) or index signal (pilot) take the chooser carrier wave as transmission parameter signaling is to produce this sub-carrier channels gain signal P _H ^T

This second adding up device 450 is connected to this first multiplier 430, to all sub-carrier channels gains

Carry out accumulating operation, and produce this average channel gain signal P _H

Wherein, k sub-carrier channels gain

Available following formula represents:

$P_{H_k}={\left((1/N_F){\mathrm{\Σ}}_i^{N_F}\right|H_{i,k}\left|\right)}^2,$

This average channel gain signal P _HAvailable following formula represents:

${\stackrel{\‾}{P}}_H=(1/M){\mathrm{\Σ}}_{k=1}^M{P}_{H_k},$

This sub-carrier channels gain signal P _H ^TAvailable following formula represents:

$P_H^T\≡\left\{P_{H_k}\right|k\∈I_T\},$

Wherein, I _TFor subcarrier is the set that the index of transmission parameter signaling or index signal forms.

This selection equilibration device 140 is connected to this energy estimating apparatus 120 and this channel gain calculation element 130, according to criterion signal mu, this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal P _H ^T, select and produce the average signal power set

, the ensemble average noise power

, and average channel gain set

Fig. 5 is the calcspar that the present invention should select equilibration device 140, and this selection equilibration device 140 comprises the 3rd adding up device 510, candidate searcher 520, reaches the second choice device 530.

The 3rd adding up device 510 is connected to this energy estimating apparatus 120 and this first choice device 440, with to this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal P _H ^TCarry out accumulating operation, and produce respectively average signal power S, average noise power N, and average channel gain P.That is the 3rd adding up device 510 have three sub-adding up devices, with respectively to this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal P _H ^TCarry out accumulating operation, and produce respectively average signal power S, average noise power N, and average channel gain P.

This candidate searcher 520 is connected to this energy estimating apparatus 120 and this first choice device 440, according to the criterion signal mu with to this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal P _H ^TCarry out search and selection, and produce qualified sub-carrier indices set V _μ, and this qualified sub-carrier indices number of sets N _V

Fig. 6 is the calcspar of this candidate searcher 520 of the present invention, and this candidate searcher 520 comprises candidate selecting device 610 and number calculation element 620.

As shown in Figure 6, this average signal power set

, this ensemble average noise power

And this average channel gain set

In subscript m be 1 to N _VWhen this criterion signal mu is cumulative (accumulation, A), the qualified sub-carrier indices set V of this of these candidate searcher 520 outputs _μBe V _A={ k|k=1}.When this criterion signal mu is whole (overall, O), the qualified sub-carrier indices set V of this of these candidate searcher 520 outputs _μBe V _O={ k|k=1～N _TPS.When this criterion signal mu is k sub-carrier channels gain

During greater than threshold value (η), the qualified sub-carrier indices set V of this of these candidate searcher 520 outputs _μFor When this criterion signal mu is k subcarrier peak signal signal to noise ratio, the qualified sub-carrier indices set V of this of these candidate searcher 520 outputs _μFor when this criterion signal mu is k subcarrier maximum signal power, the qualified sub-carrier indices set V of this of these candidate searcher 520 outputs _μFor

When this criterion signal mu is k subcarrier maximum channel gain, the qualified sub-carrier indices set V of this of these candidate searcher 520 outputs _μFor $V_H=\left\{k\right|\arg \underset{k}{\mathrm{Max}}\left(P_{H_k}\right)\}.$

This number calculation element 620 is connected to this candidate selecting device 610, to calculate this qualified sub-carrier indices set V _μNumber N _μThat is, N _μ=| V _μ|.

This second choice device 530 is connected to the 3rd adding up device 510 and this candidate searcher 520, according to this criterion signal mu, this qualified sub-carrier indices set V _μAnd this qualified sub-carrier indices number of sets N _V, with by this average signal power

This average noise power

And this average channel gain

Select to produce the average signal power set The ensemble average noise power

And average channel gain set

This combination and calculation element 150 are connected in this selection equilibration device 140 and this channel gain calculation element 130, according to this criterion signal mu, this average signal power set This ensemble average noise power

This average channel gain set

And this average channel gain signal

To produce estimating signal signal to noise ratio γ _μ

Fig. 7 is the calcspar of this combination of the present invention and calculation element 150, and this combination and calculation element 150 comprise the first calculation element 710, the second calculation element 720, the 3rd calculation element 730, reach the 3rd choice device 740.

This first calculation element 710 is connected in this selection equilibration device 140 and this channel gain calculation element 130, according to this average signal power set

, this ensemble average noise power

And this average channel gain set

And produce the first estimating signal noise.The following formula of these first calculation element, 710 foundations is to produce this first estimating signal noise:

${\mathrm{\γ}}_1=\frac{{\tilde{S}}_1^{\mathrm{\μ}}}{{\tilde{N}}_1^{\mathrm{\μ}}}\·\frac{{\stackrel{\‾}{P}}_H}{{\tilde{P}}_1^{\mathrm{\μ}}}.---\left(1\right)$

This second calculation element 720 is connected in this selection equilibration device 140 and this channel gain calculation element 130, according to this average signal power set

, this ensemble average noise power

This average channel gain set

And this average channel gain signal P _H, and produce the second estimating signal noise.The following formula of these second calculation element, 720 foundations is to produce this second estimating signal noise:

${\mathrm{\γ}}_2=\frac{{\stackrel{\‾}{P}}_H\·\underset{m=1}{\overset{N_V}{\mathrm{\Σ}}}\left(\frac{{\tilde{S}}_m^{\mathrm{\μ}}}{{\tilde{P}}_m^{\mathrm{\μ}}}\right)}{\underset{m=1}{\overset{N_V}{\mathrm{\Σ}}}\left({\tilde{N}}_m^{\mathrm{\μ}}\right)}.---\left(2\right)$

The 3rd calculation element 730 is connected in this selection equilibration device 130 and this channel gain calculation element 140, according to this average signal power set

, this ensemble average noise power

This average channel gain set

And this average channel gain signal P _H, and produce the 3rd estimating signal noise.The following formula of the 3rd calculation element 730 foundations is to produce the 3rd estimating signal noise:

${\mathrm{\γ}}_3={\stackrel{\‾}{P}}_H\·\{\underset{m=1}{\overset{N_V}{\mathrm{\Π}}}\frac{{\tilde{S}}_m^{\mathrm{\μ}}}{{\tilde{N}}_m^{\mathrm{\μ}}}\·\frac{1}{{\tilde{P}}_m^{\mathrm{\μ}}}\}.---\left(3\right)$

The 3rd choice device 740 is connected to this first calculation element 710, this second calculation element 720, reaches the 3rd calculation element 730, according to this criterion signal mu, to select this first estimating signal noise, this second estimating signal noise, the 3rd estimating signal noise, to be output as this estimating signal signal to noise ratio γ _μ

This dB value conversion equipment 160 is connected in this combination and calculation element 150, with this estimating signal signal to noise ratio γ _μBe converted to the dB value.

By above stated specification as can be known, the technology of the present invention is used for multi-path channel.When the technology of the present invention is applied to awgn channel, estimating signal signal to noise ratio γ _μFor:

${\mathrm{\γ}}_{\mathrm{\μ}}={\left\{\underset{m=1}{\overset{N_V}{\mathrm{\Π}}}\frac{{\tilde{S}}_m^{\mathrm{\μ}}}{{\tilde{N}}_m^{\mathrm{\μ}}}\right\}}^{\frac{1}{N_V}}.---\left(4\right)$

Fig. 8 is of the present invention for digital ground multimedia broadcast (Digital TerrestrialMultimedia Broadcasting, DTMB) be the analog result schematic diagram of estimating system of the Signal-to-Noise of the blind transmission parameter signalling of example or index signal, it uses 36 index signals under AWGN, and uses the sub-energy estimating apparatus 121 of the relevance among Fig. 2 and criterion signal mu to be cumulative (μ=A).As shown in Figure 8, under PN945 and two kinds of patterns of PN420, when Signal-to-Noise during less than 22dB, estimating signal signal to noise ratio (dB) and the actual difference of Signal-to-Noise (dB) that measures are less than 1dB.That is the estimating signal signal to noise ratio (dB) of the technology of the present invention is very near actual value.

Fig. 9 is that another simulation of estimating system of the Signal-to-Noise of the blind transmission parameter signalling for digital ground multimedia broadcast of the present invention or index signal shows that the result is intended to, it is used for the SARFT-8 multi-path channel and is in the PN420/QPSK pattern, wherein the M1 lines use sub-energy estimating apparatus 121 formula (3) of the relevance among Fig. 2, the M2 lines use time averaging sub-energy estimating apparatus 121 formula (3) among Fig. 3, and the M3 lines use sub-energy estimating apparatus 121 formula (1) of the relevance among Fig. 2.Figure 10 is the schematic diagram of the various parameters in the SARFT-8 multi-path channel.

By above stated specification as can be known, prior art does not consider to use transmission parameter signaling or index signal to help Signal-to-Noise (SNR) estimation, only considers awgn channel, and the multi-path channel when not considering actual transmissions.And the present invention uses transmission parameter signaling or index signal helping the Signal-to-Noise estimation, and this kind mode can be than prior art estimating signal signal to noise ratio more exactly, and makes communication system can calibrate to better situation.Simultaneously, and the present invention not only considers awgn channel, the transmission situation of multi-path channel when also considering actual transmissions, the Signal-to-Noise in the time of also estimating actual transmissions more accurately than prior art.

From the above, no matter the present invention with regard to purpose, means and effect, shows that all it is different from the feature of prior art, has practical value.It should be noted that above-mentioned many embodiment only give an example for convenience of explanation, the interest field that the present invention advocates should be as the criterion so that claims scope is described certainly, but not only limits to above-described embodiment.

Claims (18)

1. estimating system that is used for the Signal-to-Noise of multicarrier system, this estimating system comprises:

The phase rotating device receives qam symbol signal { Y _{I, k}And the channel estimating signal Laggard line phase rotary manipulation is to produce rotation qam symbol signal

And rotation channel estimating signal

The energy estimating apparatus is connected in this phase rotating device and comprises N _TPSIndividual sub-energy estimating apparatus is to rotate the qam symbol signal to this

In each subcarrier, carry out the energy estimation, and produce signal energy signal S ^TAnd noise energy signal N ^T, N wherein _TPSBe positive integer;

The channel gain calculation element is connected in this phase rotating device, according to this rotation channel estimating signal

And generation sub-carrier channels gain signal

And average channel gain signal

Select equilibration device, be connected to this energy estimating apparatus and this channel gain calculation element, according to criterion signal mu, this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal

Select and produce the average signal power set

The ensemble average noise power

And average channel gain set And

Combination and calculation element are connected in this selection equilibration device and this channel gain calculation element, according to this criterion signal mu, this average signal power set This ensemble average noise power

This average channel gain set

And this average channel gain signal

To produce estimating signal signal to noise ratio γ _μ

Wherein, this channel gain calculation element comprises:

Buffer, the number N of storage figure frame _F

The first adding up device is connected to this buffer and this phase rotating device, so that this is rotated the channel estimating signal Carry out accumulating operation, and produce cumulative rotation channel estimating signal

The first multiplier is connected to this first adding up device, with the rotation channel estimating signal that should add up

Multiply each other, to produce k sub-carrier channels gain

The first choice device is connected to this first multiplier, take the chooser carrier wave as transmission parameter signaling or channel gain corresponding to index signal, to produce this sub-carrier channels gain signal

And

The second adding up device is connected to this first multiplier, to all sub-carrier channels gains Carry out accumulating operation, and produce this average channel gain signal

Wherein, this selection equilibration device comprises:

The 3rd adding up device is connected to this energy estimating apparatus and this first choice device, with to this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal

Carry out accumulating operation, and produce respectively average signal power

Average noise power And average channel gain

The candidate searcher is connected to this energy estimating apparatus and this first choice device, according to the criterion signal mu with to this signal energy signal S ^T, this noise energy signal N ^T, and this sub-carrier channels gain signal

Carry out search and selection, and produce qualified sub-carrier indices set V _μ, and this qualified sub-carrier indices number of sets N _VAnd

The second choice device is connected to the 3rd adding up device and this candidate searcher, according to this criterion signal mu, this qualified sub-carrier indices set V _μAnd this qualified sub-carrier indices number of sets N _V, with by this average signal power

This average noise power

And this average channel gain Select to produce the average signal power set The ensemble average noise power And average channel gain set

Wherein, this combination and calculation element comprise:

The first calculation element is connected in this selection equilibration device and this channel gain calculation element, according to this average signal power set

This ensemble average noise power

And this average channel gain set

And produce the first estimating signal noise;

The second calculation element is connected in this selection equilibration device and this channel gain calculation element, according to this average signal power set This ensemble average noise power

This average channel gain set

And this average channel gain signal

And produce the second estimating signal noise;

The 3rd calculation element is connected in this selection equilibration device and this channel gain calculation element, according to this average signal power set This ensemble average noise power

This average channel gain set

And this average channel gain signal And produce the 3rd estimating signal noise; And

The 3rd choice device, be connected to this first calculation element, this second calculation element, reach the 3rd calculation element, according to this criterion signal mu, to select this first estimating signal noise, this second estimating signal noise, the 3rd estimating signal noise, to export as this estimating signal signal to noise ratio γ _μ

2. estimating system as claimed in claim 1, it further comprises:

DB value conversion equipment is connected in this combination and calculation element, with this estimating signal signal to noise ratio γ _μBe converted to the dB value.

3. estimating system as claimed in claim 2, wherein, this phase rotating device is to qam symbol signal { y _{I, k}And the channel estimating signal

Rotate respectively negative ∠ H _{I, k}Angle, and produce this rotation qam symbol signal

And this rotation channel estimating signal

4. estimating system as claimed in claim 3, wherein, this rotation qam symbol signal

Available following formula represents:

${\tilde{Y}}_{i,k}=Y_{i,k}\·e^{-j\∠H_{i,k}},$

This rotation channel estimating signal

Available following formula represents:

${\tilde{H}}_{i,k}=H_{i,k}\·e^{-j\∠H_{i,k}}=\left|H_{i,k}\right|,$

Wherein,

Be this rotation qam symbol signal

Frequency domain represent mode.

5. estimating system as claimed in claim 4, wherein, this each sub-energy estimating apparatus comprises relevance energy estimating apparatus.

6. estimating system as claimed in claim 4, wherein, this each sub-energy estimating apparatus comprises time average energy estimating apparatus.

7. estimating system as claimed in claim 6, wherein, this k sub-carrier channels gain Available following formula represents:

$P_{H_k}={\left((1/N_F){\mathrm{\Σ}}_i^{N_F}\right|H_{i,k}\left|\right)}^2,$

This average channel gain signal

Available following formula represents:

${\stackrel{\‾}{P}}_H=(1/M){\mathrm{\Σ}}_{k=1}^M{P}_{H_k},$

This sub-carrier channels gain signal

Available following formula represents:

$P_H^T\≡\left\{P_{H_k}\right|k\∈I_T\},$

Wherein, I _TFor subcarrier is the set that the index of transmission parameter signaling or index signal forms, N _FNumber for the figure frame.

8. estimating system as claimed in claim 7, wherein, this average signal power set

This ensemble average noise power

And this average channel gain set

In subscript m be 1 to N _V

9. estimating system as claimed in claim 8, wherein, when this criterion signal mu during for cumulative (accumulation, A), this candidate searcher output should qualified sub-carrier indices gather V _μBe V _A={ k|k=1}.

10. estimating system as claimed in claim 9, wherein, when this criterion signal mu is all when (overall, O), this candidate searcher output should qualified sub-carrier indices gather V _μBe V _O={ k|k=1～N _TPS.

11. estimating system as claimed in claim 10, wherein, when this criterion signal mu is k sub-carrier channels gain

During greater than threshold value η, the qualified sub-carrier indices set of this of this candidate searcher output V _μFor

12. estimating system as claimed in claim 11, wherein, when this criterion signal mu is k subcarrier peak signal noise signal to noise ratio, the qualified sub-carrier indices set of this of this candidate searcher output V _μFor

Wherein, S _kBe k sub-carrier signal energy signal, N _kBe k subcarrier noise energy signal.

13. estimating system as claimed in claim 12, wherein, when this criterion signal mu is k subcarrier maximum signal power, the qualified sub-carrier indices set of this of this candidate searcher output V _μFor

Wherein, Be k sub-carrier signal power.

14. estimating system as claimed in claim 13, wherein, when this criterion signal mu is k sub year maximum ripple channel gain, the qualified sub-carrier indices set of this of this candidate searcher output V _μFor

15. estimating system as claimed in claim 14, wherein, the following formula of this first calculation element foundation is to produce this first estimating signal noise:

${\mathrm{\γ}}_1=\frac{{\tilde{S}}_1^{\mathrm{\μ}}}{{\tilde{N}}_1^{\mathrm{\μ}}}\·\frac{{\stackrel{\‾}{P}}_H}{{{\tilde{P}}_1}^{\mathrm{\μ}}},$

Wherein,

Be this average signal power set

Middle subscript m is 1 project,

Be this ensemble average noise power

Middle subscript m is 1 project,

Be this average channel gain set

Middle subscript m is 1 project.

16. estimating system as claimed in claim 15, wherein, the following formula of this second calculation element foundation is to produce this second estimating signal noise:

${\mathrm{\γ}}_2=\frac{{\stackrel{\‾}{P}}_H\·\underset{m=1}{\overset{N_V}{\mathrm{\Σ}}}\left(\frac{{\tilde{S}}_m^{\mathrm{\μ}}}{{\tilde{P}}_m^{\mathrm{\μ}}}\right)}{\underset{m=1}{\overset{N_V}{\mathrm{\Σ}}}\left({\tilde{N}}_m^{\mathrm{\μ}}\right)}.$

17. estimating system as claimed in claim 16, wherein, the following formula of the 3rd calculation element foundation is to produce the 3rd estimating signal noise:

${\mathrm{\γ}}_3={\stackrel{\‾}{P}}_H\·\{\underset{m=1}{\overset{N_V}{\mathrm{\Π}}}\frac{{\tilde{S}}_m^{\mathrm{\μ}}}{{\tilde{N}}_m^{\mathrm{\μ}}}\·\frac{1}{{\tilde{P}}_m^{\mathrm{\μ}}}\}.$

18. estimating system as claimed in claim 16, wherein, when the AWNG channel, estimating signal signal to noise ratio γ _μFor:

${\mathrm{\γ}}_{\mathrm{\μ}}={\left\{\underset{m=1}{\overset{N_V}{\mathrm{\Π}}}\frac{{\tilde{S}}_m^{\mathrm{\μ}}}{{\tilde{N}}_m^{\mathrm{\μ}}}\right\}}^{\frac{1}{N_V}}.$

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