CN106411338A - Receiving circuit capable of correcting estimation of signal-to-noise characteristic value and related method - Google Patents

Receiving circuit capable of correcting estimation of signal-to-noise characteristic value and related method Download PDF

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CN106411338A
CN106411338A CN201510458314.0A CN201510458314A CN106411338A CN 106411338 A CN106411338 A CN 106411338A CN 201510458314 A CN201510458314 A CN 201510458314A CN 106411338 A CN106411338 A CN 106411338A
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signal
noise characteristic
characteristic value
value
correction value
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苏裕哲
童泰来
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MStar Semiconductor Inc Taiwan
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MStar Semiconductor Inc Taiwan
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Abstract

The invention provides a receiving circuit capable of correcting estimation of a signal-to-noise characteristic value (such as a signal-to-noise ratio) and a related method. The receiving circuit comprises an equalizer, a cutter, an estimation circuit and a correction circuit, the equalizer can provide an equalization signal according to a reception signal, the cutter can interpret digital information in the equalization signal and provide a cutting signal according to the digital information, the estimation circuit can provide an initial signal-to-noise characteristic value according to the equalization signal and the cutting signal, and the correction circuit can provide a corresponding correction value according to the value of the initial signal-to-noise characteristic value and correct the initial signal-to-noise characteristic value according to the corresponding correction value in order to generate a corrected signal-to-noise characteristic value.

Description

Receiving circuit and the correlation technique of the estimation of signal-to-noise characteristic value can be revised
Technical field
The present invention is with regard to a kind of receiving circuit revising the estimation of signal-to-noise characteristic value and correlation technique espespecially one Kind can cut what the signal to noise ratio mistake that (slicing) led to was over-evaluated by modifying factor hard decision (hard decision) Receiving circuit and correlation technique.
Background technology
Wired and/or Radio Network System be advanced information society indispensable.Wired and/or wireless network Network system includes transmitting terminal and receiving terminal, is connected with channel (channel) between transmitting terminal and receiving terminal；Lift For example, this channel can be the wireless channel being formed by air medium/space, or by netting twine, power line The wire message way of formation such as (power line).Coding digital information can be modulated to transmission signal by transmitting terminal, Concurrently it is incident upon on channel, channel propagates to receiving terminal, more simultaneously demodulating and decoding is received by receiving terminal and believe for numeral Breath.
But, in network system during transmission signal, inherently affected by noise, for example say it is that additivity is white Color Gaussian noise (AWGN, additive white Gaussian noise).Therefore, between signal and noise Relation also just becomes significant consideration when design, enforcement, arrangement, optimization network system.Signal with make an uproar Relation between sound can be quantified as signal-to-noise characteristic value, such as signal to noise ratio, in order to reflect signal power and noise power Ratio.In contrast to the power of the transmission signal of real carry information, if the power of noise is relatively low, The numerical value of signal to noise ratio can be higher, is less susceptible to by noise jamming by the transmission signal of transmitting terminal to receiving terminal, therefore can In higher accuracy (relatively low error rate, error rate), information is delivered to receiving terminal by transmitting terminal.
Modernization network system in, receiving terminal can estimate signal to noise ratio, enable receiving terminal and/or transmitting terminal according to Adaptively adjust signal transmitting and/or the running receiving according to signal to noise ratio.For example, in advanced power line network In network system, when the signal to noise ratio numerical value that receiving terminal estimates is higher, receiving terminal will be considered that information instantly passes Defeated all right, and and then feedback notify transmitting terminal, make transmitting terminal advance the speed (rate).Conversely, working as When signal to noise ratio numerical value that receiving terminal estimates is relatively low, receiving terminal will be considered that information transfer instantly is ill-conditioned, Data transmission easily malfunctions, therefore receiving terminal notice capable of feedback transmitting terminal, make transmitting terminal minimizing speed, so may be used Obtain optimal flow (throughput).
But, for receiving terminal, because the essence of noise is random, and can be with real carry information Signal mixes (superposition) together, therefore receiving terminal is only capable of drawing the signal to noise ratio of estimation, and this estimates signal to noise ratio Differ and surely reflect real signal to noise ratio.If the signal to noise ratio that receiving terminal estimates and real signal to noise ratio difference mistake Greatly, when network system is according to the miscellaneous ratio adaptively running of the transmitting of adjustment signal and/or reception of estimation news, just Running effect of network system can be affected.For example, if the signal to noise ratio that estimates of receiving terminal more optimistic and Higher than real signal to noise ratio, transmitting terminal can be made to increase the speed of information transfer by mistake；Though however, information transport stream Amount is high, but error rate also can be higher, because the signal that receiving terminal really receives is done by strong noise Disturb；Accordingly, it is capable to the information content of correctly effectively transmission reduces on the contrary.
Content of the invention
The one of the purpose of the present invention is to provide one kind can revise the reception that signal-to-noise characteristic value (as signal to noise ratio) is estimated Circuit (as 20, Fig. 1), it in a receiving terminal of a network system, and can include a balanced device (such as 24) a, slicer (as 26), an estimating circuit (as 28) and a correcting circuit (as 30).All Weighing apparatus can provide an equalizing signal (as s2) according to a receipt signal (as s1).Slicer couples this equilibrium Device, can digital information in this equalizing signal of interpretation, to provide one to cut signal (such as according to this equalizing signal s3).Estimating circuit couples this balanced device and this slicer, in order to cut signal according to this equalizing signal with this Difference provide an initial signal-to-noise characteristic value (as SNRi [k]).Correcting circuit couples this estimating circuit, according to There is provided a corresponding correction value (as r [k]) according to the numerical value of this initial signal-to-noise characteristic value, and according to this corresponding correction Value revises this initial signal-to-noise characteristic value, to produce a correction signal-to-noise characteristic value (as SNRc [k]).
A lookup table circuit (as 34) and a multiplier (as 32) is may include in this correcting circuit.Table look-up electricity Road can store multiple preset correction value (as e [p, 1] to e [p, N], Fig. 6), and according to this initial signal-to-noise characteristic Value provides this corresponding correction value with these preset correction value；Wherein, respectively this preset correction value correspond to multiple pre- If one of them of signal-to-noise characteristic value (as SNRt [1] to SNRt [N]).Multiplier couples this lookup table circuit With this estimating circuit, this initial signal-to-noise characteristic value can be multiplied by this correspondence correction value, and produce this correction according to this Signal-to-noise characteristic value.In one embodiment, preset with these according to this initial signal-to-noise characteristic value when this lookup table circuit and repair When this corresponding correction value is provided, be by seek in these default signal-to-noise characteristic values one initial closest to this (as SNRt [n]) of signal-to-noise characteristic value, and the default signal-to-noise characteristic value that this is sought correlated this preset Correction value (as e [p, n]) is as this corresponding correction value.Arrange from small to large with these default signal-to-noise characteristic values Row, corresponding these preset correction value at least fractional numbers meeting is in first one first growth trend change, It is in one second growth trend change again, and this first growth trend is contrary with this second growth trend.For example, This first growth trend can be strictly decreasing (or monotone decreasing), the second growth trend can for strictly increasing (or Monotonic increase).
This correcting circuit more sets according to a modulation of this receipt signal and provides this corresponding correction value.One embodiment In, this receipt signal comprises the second number (more than or equal to 1, such as K) individual carrier wave (as s1 [1] to s1 [K]), And correspond to numeral letter in upper the carrying according to corresponding modulating setting (as ms [k]) of respectively this carrier wave (as s1 [k]) Breath, and respectively this corresponding modulating setting of this carrier wave is to be preset by the first number (more than or equal to 1, such as P) is individual Modulation sets MS [1] to selected in MS [P].For example, preset modulation and set MS [1] to MS [P] Can be binary phase shift modulated (binary phase shift keying, hereinafter referred to as BPSK), quaternary respectively Phase shift modulated (quadrature phase shift keying, hereinafter referred to as QPSK), eight yuan of orthogonal amplitudes are adjusted System (quadrature amplitude modulation, hereinafter referred to as 8QAM), ten hexa-atomic quadrature amplitude modulation (hereinafter referred to as 16QAM), 60 quaternary quadrature amplitude modulation (hereinafter referred to as 64QAM), 205 Ten hexa-atomic quadrature amplitude modulation (hereinafter referred to as 256QAM), 1,020 quaternary quadrature amplitude modulation (with Lower abbreviation 1024QAM) and 4,090 hexa-atomic quadrature amplitude modulation (hereinafter referred to as 4096QAM).
This estimating circuit is that respectively this carrier wave s1 [k] provides initial signal-to-noise characteristic value SNRi [k].This correcting circuit It is then to set according to this corresponding modulating of respectively this initial signal-to-noise characteristic value SNRi [k] of this carrier wave and respectively this carrier wave Ms [k] and be that respectively this carrier wave provides corresponding correction value r [k], and repair according to this correspondence correction value of respectively this carrier wave This initial signal-to-noise characteristic value of just each this carrier wave, to produce a correction signal-to-noise characteristic value for respectively this carrier wave SNRc[k].In this correcting circuit, this lookup table circuit be respectively this default modulation set MS [p] (p=1 to P, Fig. 6) store multiple preset correction value e [p, 1] to e [p, N], and set according to this corresponding modulating of respectively this carrier wave This initial signal-to-noise characteristic value SNRi [k] of ms [k], respectively this carrier wave sets MS [1] extremely with respectively this default modulation These preset correction value e [1,1] of MS [P] to e [P, 1] ..., e [1, N] to e [P, N] and be each this carrier wave s1 [k] This correspondence correction value SNRc [k] is provided.Wherein, respectively this default modulation sets respectively this default correction of MS [p] Value e [p, n] (to n=1 to N) is to close to be connected in multiple default signal-to-noise characteristic values SNRt [1] to SNRt [N] One of them SNRt [n].This multiplier then respectively should in order to be multiplied by this initial signal-to-noise characteristic value of respectively this carrier wave This corresponding correction value of carrier wave, and produce this correction signal-to-noise characteristic value of respectively this carrier wave according to this.
When this lookup table circuit is that respectively this carrier wave s1 [k] provides this correspondence correction value r [k], it is by these default tune Set up and determine in MS [1] to MS [P], to find out (the vacation that this corresponding modulating meeting respectively this carrier wave sets ms [k] Be set to MS [p1]), and by these default signal-to-noise characteristic values SNRt [1] seek to SNRt [N] one connects most (being assumed to be SNRt [n1]) of nearly respectively this initial signal-to-noise characteristic value SNRi [k] of this carrier wave, to meet at this Default modulation set the default letter that this is sought to e [p1, N] by these preset correction value e [p1,1] of MS [p] This preset correction value e [p1, n1] that characteristic value SNRt of making an uproar [n] is correlated is as this corresponding correction of respectively this carrier wave Value r [k].Arrange from small to large to SNRt [N] with these default signal-to-noise characteristic values SNRt [1], be somebody's turn to do same Default modulation sets in these preset correction value e [p, 1] to e [p, N] of MS [p], and at least fractional numbers should Preset correction value can first be in one first growth trend change, then in one second growth trend change, and this first Growth trend is contrary with this second growth trend.Set MS [1] with these default modulation to MS [P] in list The bit number carrying in the time of position arranges, from small to large corresponding to same default signal-to-noise characteristic value SNRt [n] And corresponding to different default multiple this preset correction value e [1, n] modulating setting to e [P, n], at least part Number meeting assumes trend decrescence.
In one embodiment, this second number carrier wave is OFDM (OFDM, orthogonal Frequency-division multiplexing) under multiple carrier waves.
In one embodiment, this receiving circuit further includes a bit load (bit loading), and initialization circuit is (such as 38), couple this correcting circuit, in order to produce a feedback letter according to this correction signal-to-noise characteristic value of respectively this carrier wave Number (such as s4, Fig. 1) to radiating circuit (as 10), is set with this corresponding modulating updating respectively this carrier wave, So that this radiating circuit can be set according to the corresponding modulating after this renewal of respectively this carrier wave and carry on each carrier wave Following digital information.
One purpose of the present invention is to provide a kind of side that can revise the estimation of signal-to-noise characteristic value in a receiving circuit Method, including：There is provided an equalizing signal (equalized according to the receipt signal that this receiving circuit is received Signal), wherein this receipt signal can comprise the individual carrier wave s1 of the second number (K) [1] to s1 [K], and in each This carrier wave s1 [k] is upper to be set ms [k] according to a corresponding modulating and carries corresponding digital information, and respectively this carrier wave should It is to set MS [1] to selected in MS [P] by the individual default modulation of the first number (P) that corresponding modulating sets ms [k] Go out；Carry out one and cut step, provide one to cut signal according to this equalizing signal；Carry out an estimating step, according to There is provided an initial signal-to-noise characteristic value according to the difference that this equalizing signal cuts signal with this for respectively this carrier wave SNRi[k]；And, carry out an aligning step, the numerical value according to respectively this initial signal-to-noise characteristic value of this carrier wave carries For corresponding correction value r [k], and according to respectively this correspondence correction value of this carrier wave and this initial signal-to-noise characteristic value are repaiied This initial signal-to-noise characteristic value of just each this carrier wave, to produce a correction signal-to-noise characteristic value for respectively this carrier wave SNRc[k].
Wherein, the step of this correspondence correction value is provided to further include according to this initial signal-to-noise characteristic value：Connect according to this One modulation of the collection of letters number sets, this initial signal-to-noise characteristic value provides this corresponding correction with multiple preset correction value Value；Wherein, respectively this preset correction value corresponds to one of them of multiple default signal-to-noise characteristic values；And, By seek in these preset correction value its corresponding default signal-to-noise characteristic value of a preset correction value is first closest to this Beginning signal-to-noise characteristic value is providing this correspondence correction value.
For example, when providing this correspondence correction value for respectively this carrier wave, it is to set MS [1] by these default modulation Find out this corresponding modulating meeting respectively this carrier wave and set (being assumed to be of ms [k] to MS [P] MS [p1]), and by these default signal-to-noise characteristic values SNRt [1] seek to SNRt [N] one closest to each (being assumed to be SNRt [n1]) of this initial signal-to-noise characteristic value of this carrier wave, is set with the default modulation meeting at this Default signal-to-noise characteristic value SNRt [n1] that this is sought to e [p1, N] by fixed these preset correction value e [p1,1] Corresponding this preset correction value e [p1, n1] is as this corresponding correction value r [k] of respectively this carrier wave.
Brief description
It is that the above objects, features and advantages of the present invention can be become apparent, below in conjunction with accompanying drawing to this Bright specific embodiment elaborates, wherein：
Fig. 1 illustrates that the receiving circuit according to one embodiment of the invention.
Fig. 2 illustrates that the constellation point under a default modulation setting on a scatter diagram.
Fig. 3 illustrates that a decision-making interval divides.
Fig. 4 a, 4b illustrate respectively fixed boundary decision-making interval divide with its signal-to-noise characteristic value misvalue situation.
Fig. 5 illustrates that the signal-to-noise characteristic value that different modulating sets under the decision-making interval of fixed boundary divides is missed Estimate.
Fig. 6 illustrates that the form according to one embodiment of the invention, in order to provide correction value.
Fig. 7 illustrates an embodiment of Fig. 6 form.
Fig. 8 illustrates that the correction signal-to-noise characteristic value after uncorrected initial signal-to-noise characteristic value and correction.
Fig. 9 illustrates that the flow process according to one embodiment of the invention.
10：Radiating circuit
12：Channel
20：Receiving circuit
22：Channel estimation circuit
24：Balanced device
26：Slicer
28：Estimating circuit
30：Correcting circuit
32：Multiplier
34：Lookup table circuit
36：Application circuit
38：Bit load initialization circuit
s0-s4：Signal
s0[k]-s3[k]：Carrier wave
SNRi[k]：Initial signal-to-noise characteristic value
SNRc[k]：Revise signal-to-noise characteristic value
r[k]：Correction value
MS[1]-MS[P]：Default modulation sets
ms[k]：Modulation sets
c[p,1,1]-c[p,I[p],Q[p]]：Constellation point
a[p]：Distance
SNRt[1]-SNRt[N]：Default signal-to-noise characteristic value
e[1,1]-e[P,N]：Preset correction value
sa0、sa、sb、sc、z1-z4、a1-a4、a20、a30、a40、b1-b4、b20、b30、b40： Point
B[p]：Border
D[p]：Decision-making interval divides
d[p,1,1]-d[p,I[p],Q[p]]：Decision-making interval
va、vb、vc、v0、v1e-v4e、v2-v3：Vector
400、500、600、700：Straight line
410、501-508、610、701-708、901-908、1000-1002、1100-1102：Curve
SNR0：Correct signal-to-noise characteristic value
h1-h3、h11、h12、h1a、h2a、h10、u1、u11：Value
800：Form
1200：Flow process
1202-1208：Step
Specific embodiment
Refer to Fig. 1, it is illustrated that the receiving circuit 20 according to one embodiment of the invention, it can be via One channel 12 receives the signal s0 that a radiating circuit 10 is sent.For example, radiating circuit 10 with connect Receive a transmitting terminal and the receiving terminal that circuit 20 can be respectively arranged at a network system.Channel 12 can be Wired or wireless channel；For example, channel 12 can be the power line of transmission alternating electromotive force.Work as transmitting When digital information is transferred to receiving circuit 20 by circuit 10, radiating circuit 10 can be by coding digital information It is modulated to signal s0, signal s0 transmits to receiving circuit 20 via channel 12；Transmit via channel 12, Signal s0 affected by noise can be changed into a signal s1 (receipt signal).A letter is may include in receiving circuit 20 Channel estimation circuit 22, a balanced device 24, a slicer 26, an estimating circuit 28 and an application circuit 36； For realizing the purpose of correction signal-to-noise characteristic value of the present invention, in receiving circuit 20, further include a correcting circuit 30.
In one example, may include K carrier wave s0 [1] in signal s0 to s0 [K]；Within a unit interval, Radiating circuit 10 can set ms [k] (not shown) by symbol smb [k] (not shown) according to a modulation Digital data modulation carry to carrier wave s0 [k].It can be pre- by P that the modulation of carrier wave s0 [k] sets ms [k] If modulation sets MS [1] to selected in MS [P]；, preset modulation and set MS [1] extremely taking P=8 as a example MS [8] can be respectively modulation system BPSK, QPSK of OFDM, 8QAM, 16QAM, 64QAM, 256QAM, 1024QAM and 4096QAM.The modulation of different carrier s0 [k1] and s0 [k2] Setting ms [k1] can be identical or different with ms [k2].The modulation of same carrier wave s0 [k] sets ms [k] Fixation or dynamically changing；For example, when will transmit first symbol, carrier wave s0 [1] Modulation set ms [1] and MS [1] (BPSK) can be set using default modulation；When transmitting another symbol, carry Modulation setting ms [1] of ripple s0 [1] can change adopts default modulation setting MS [2] (QPSK).
Each default modulation sets MS [p] and can carry digital information according to the individual constellation point of M [p]；Continue Fig. 1, Please also refer to Fig. 2, it is the individual star of M [p] illustrating a certain default modulation to set MS [p] in a scatter diagram Seat point c [p, i, q] (i=1 to I [p], q=1 to Q [p])；Wherein, M [p]=I [p] * Q [p].The transverse axis of Fig. 2 Represent parallel phase place (in-phase) component of each constellation point c [p, i, q], the longitudinal axis then represents each constellation point c [p, i, q] Quadrature phase (quadrature-phase) component；For example, if a certain default modulation sets MS [4] it is 16QAM, then its can according to M [4]=I [4] * Q [4]=4*4=16 constellation point c [4,1,1], c [4,1,2], C [4,2,1], c [4,2,2] ..., c [4, i, q] ... to carry digital information to c [4,4,4].Each constellation point c [p, i, q] Coordinate (AI [p, i, q], AQ [p, i, q]) (not shown) can be equal to ((i-0.5*I [p] -0.5) * a [p], (q-0.5*Q[p]-0.5)*a[p])；Wherein, project a [p] is the distance between two adjacent constellation point, as Fig. 2 marks Show.For example, if it is 16QAM, i=1, q=1 that a certain default modulation sets MS [4], then constellation point The coordinate (AI [4,1,1], AQ [4,1,1]) of c [4,1,1] is equal to ((1-0.5*4-0.5) * a [p], (1-0.5*4-0.5) * a [p])=(- 1.5*a [p], -1.5*a [p]).Each constellation point c [p, i, q] The digital presupposed information SMB [p, i, q] (not shown) of a symbol, each presupposed information SMB [p, i, q] can be corresponded to Can be log2The combination of (M [p]) individual bit；So that a certain default modulation setting MS [4] is as 16QAM as a example, Each numeral presupposed information SMB [4, i, q] corresponding to each constellation point c [4, i, q] can be log2(16)=4 ratios Special combination.In signal s0, when radiating circuit 10 (Fig. 1) will be in carrier wave s0 [k] using default modulation When setting MS [p] sets ms [k] to carry a certain presupposed information SMB [p, i, q] as its modulation, you can foundation AI [p, i, q] * cos (2* π * f [k] * t)+AQ [p, i, q] * sin (2* π * f [k] * t) (not shown) is forming carrier wave S0 [k], wherein, project f [k] is the frequency of carrier wave s0 [k], and project t is the time.
For example, if it is QPSK that a certain default modulation sets MS [p1], its total M [p1]=4 Constellation point c [p1,1,1], c [p1,2,1], c [p1,1,2] and c [p1,2,2], its corresponding presupposed information SMB [p1,1,1], SMB [p1,2,1], SMB [p1,1,2] to SYM [p1,2,2] can be respectively log2(M [p1])=log2(4) the 00 of=2 bits, 10,01,11.Due to power normalization (normalization) Reason, the distance for MS [p1] and MS [p2] is set to different default modulation, between adjacent constellation point A [p1] and a [p2] can be different.For example, it is respectively if default modulation sets MS [1] to MS [P] BPSK, QPSK, 8QAM, 16QAM, 64QAM, 256QAM, 1024QAM and 4096QAM, Then apart from a [1]>a[2]>…>a[P].
Please once again with reference to Fig. 1.Via the transmission of channel 12, the K carrier wave s0 [1] of signal s0 to s0 [K] K carrier wave s1 [1] in signal s1 can be formed respectively to s1 [K].In receiving circuit 20, balanced device 24 It is coupled to channel 12, in order to the carrier wave s1 [1] to s1 [K] in signal s1 is carried out with equilibrium running, shape respectively Become the carrier wave s2 [1] to s2 [K] in signal s2.Slicer 26 couples balanced device 24, in order to interpretation signal s2 In the digital information that carried to s2 [K] by each carrier wave s2 [1], and provide a signal s3 (cutting signal) according to this Each carrier wave s3 [1] to s3 [K].Estimating circuit 28 couples balanced device 24 and slicer 26, can be according to carrier wave The difference of s2 [k] and carrier wave s3 [k] and be that each carrier wave s1 [k] provides initial signal-to-noise characteristic value SNRi [k].
Continue Fig. 1 and Fig. 2, refer to Fig. 3, it is to illustrate balanced device 24 and slicer 26 with scatter diagram Running.When radiating circuit 10 sets MS [p] by a presupposed information SMB [p, i, q] according to a certain default modulation Modulate to the carrier wave s0 [k] of signal s0 (Fig. 1), and be changed into receiving circuit 20 institute via the transmission of channel 12 During carrier wave s1 [k] in the signal s1 receiving, due to the factors such as noise, carrier wave s1 [k] institute on scatter diagram Corresponding point is understood constellation point c [p, i, q] that cannot be corresponding on scatter diagram with carrier wave s0 [k] and is overlapped；Citing and Speech, the constellation point corresponding to carrier wave s0 [1] be c [p, 1,1], the point corresponding to carrier wave s1 [1] can be point sa0, Sb or sc.Balanced device 24 can carry out equilibrium treatment and so that the carrier wave s2 [k] after equilibrium is converged to carrier wave s1 [k] In one boundary B [p]；For example it is assumed that the point sa0 corresponding to carrier wave s1 [1] exceeds boundary B [p], then all The point sa corresponding to carrier wave s2 [1] after weighing apparatus will be located in boundary B [p]；Separately for example it is assumed that carrying , in boundary B [p], such as sb or sc, then corresponding to the carrier wave s2 [1] after equilibrium for point corresponding to ripple s1 [1] Point still can be located in boundary B [p].
Then, slicer 26 will set MS [p] connection using with the default modulation that carrier wave s0 [k] is adopted Decision-making interval divide D [p] carry out the digital information that interpretation carrier wave s0 [k] is carried.Decision-making interval divides D [p] It is to mark off multiple decision-making interval d [p, 1,1] to d [p, I [p], Q [p]] in boundary B [p], as shown in figure 3, respectively Decision-making interval d [p, i, q] can cover corresponding constellation point c [p, i, q], close respectively and be connected in default modulation setting The individual presupposed information SMB of the M [p] [p, 1,1] to SMB [p, I [p], Q [p]] of MS [p].Wherein, change side a kind of During the decision-making interval on boundary divides, each decision-making interval d [p, i, q] can be centered on constellation point c [p, i, q], the length of side The square apart from a [p] between equal to adjacent constellation point；And in a kind of decision-making interval of fixed boundary divides, The decision-making interval d [p, 1,1] to d [p, I [p], 1] of adjacent boundary B [p], d [p, 1,1] to d [p, 1, Q [p]], d [p, 1, Q [p]] To d [p, I [p], Q [p]] and d [p, I [p], 1] to d [p, I [p], Q [p]] (that is,：Boundary Decision-making is interval) can be at least Have a side the length of side be more than adjacent constellation point between apart from a [p], the not square centered on constellation point c [p, i, q] Shape, remaining decision-making interval outside Boundary Decision-making interval can be then centered on constellation point c [p, i, q], the length of side etc. The square apart from a [p] between adjacent constellation point.Slicer 26 is by judging carrier wave s2 [k] in scatter diagram Upper corresponding point is located in that decision-making interval, to judge the carrier wave s0 [k] that radiating circuit 10 is launched Corresponding constellation point c [p, i, q] on scatter diagram, the digital information being carried with interpretation carrier wave s0 [k].Lift For example, if as shown in figure 3, carrier wave s2 [1] is located at point sa, because point sa falls at decision-making interval d [p, 1,2], Therefore slicer 26 will judge constellation point corresponding to carrier wave s0 [1] as c [p, 1,2], and carrier wave s1 [1] is taken The digital information interpretation carrying is presupposed information SMB [p, 1,2]；If carrier wave s2 [1] is located at point sb, due to point sb Also fall at decision-making interval d [p, 1,2], thus slicer 26 will judge constellation point corresponding to carrier wave s0 [1] as C [p, 1,2], and the digital information interpretation that carrier wave s1 [1] is carried is presupposed information SMB [p, 1,2]；If carrier wave S2 [1] is located at point sc, and because point sc is to fall at decision-making interval d [p, 1,1], therefore slicer 26 will judge carrier wave Constellation point corresponding to s0 [1] is c [p, 11], and the digital information interpretation that carrier wave s1 [1] is carried is default letter Breath SMB [p, 1,1].
Then, estimating circuit 28 will be according to the point corresponding to carrier wave s2 [k] and the star corresponding to carrier wave s3 [k] Coordinate difference on scatter diagram for seat point c [p, i1, q1] to provide initial signal-to-noise characteristic value for carrier wave s1 [k] SNRi[k].For example, if carrier wave s2 [k] is located at point sa on scatter diagram, slicer 26 will be considered that originally Carrier wave s0 [k] be in constellation point c [p, 1,2], and estimating circuit 28 will be by point sa and constellation point c [p, 1,2] Between difference vector va be considered as the error of noise initiation, and to calculate initial letter according to the length of vector v a Characteristic value SNRi of making an uproar [k].In the same manner, if carrier wave s2 [k] falls in point sb, slicer 26 also will be considered that script Carrier wave s0 [k] is in constellation point c [p, 1,2], and estimating circuit 28 will be by point sb and constellation point c [p, 1,2] Between difference vector vb be considered as the error of noise initiation, and to calculate initial letter according to the length of vector v b Characteristic value SNRi of making an uproar [k].Due to point sb than point sa closer to constellation point c [p, 1,2], difference vector vb is less than Difference vector va, therefore the initial signal-to-noise characteristic value that when carrier wave s2 [k] is located at point sb, estimating circuit 28 draws can be relatively The initial signal-to-noise characteristic value that when carrier wave s2 [k] is located at point sa, estimating circuit 28 draws is high.
However, according to above-mentioned principle, the estimation running of estimating circuit 28 can occur to estimate mistake, because During data transmission frame, slicer 26 cannot really learn carrier wave s0 [k] originally in that constellation point in fact. For example it is assumed that the originally real position of the carrier wave s0 [k] of radiating circuit 10 is at constellation point c [p, 1,1], But make the carrier wave s2 [k] that receiving circuit 20 obtains drift to point sb because of larger noise.In this case, Real signal-to-noise characteristic value should be calculated according to the difference vector v0 between point sb and constellation point c [p, 1,1]. However, due to point sb be position in decision-making interval d [p, 1,2], slicer 26 can mistakenly assert carrier wave s0 [k] Originally it is in constellation point c [p, 1,2]；Jointly, estimating circuit 28 will be mistakenly according to point sb and constellation The signal-to-noise characteristic value that difference vector vb calculating between point c [p, 1,2] makes mistake.Because vector v b is than vector v 0 Short, the signal-to-noise characteristic value of mistake can be higher than real signal-to-noise characteristic value；In other words, in the scenario above, estimate Meter circuit 28 can be excessively optimistic to the estimation of signal-to-noise characteristic value.If signal-to-noise characteristic value is misestimated, network system Also can related be malfunctioned based on the adaptability running that signal-to-noise characteristic value is made.For example, if receiving terminal mistakenly Over-evaluate signal to noise ratio, can mistakenly make transmitting terminal increase the speed of information transfer；Though however, the rate of information throughput Height, but error rate also can be higher, because the signal that receiving terminal really receives is disturbed by strong noise； Accordingly, it is capable to the information bit amount of correctly effectively transmission reduces on the contrary.
Continue Fig. 1 to Fig. 3, refer to Fig. 4 a and Fig. 4 b；Set according to default modulation for radiating circuit 10 Determine the primary carrier s0 [k] that MS [p] is sent, if slicer 26 is to draw using the decision-making interval of fixed boundary Carrier wave s2 [k] interpretation after point D [p] will equalize is carrier wave s3 [k], when estimating circuit 28 according to carrier wave s2 [k] and When s3 [k] provides initial signal-to-noise characteristic value SNRi [k], it misestimates the situation of signal-to-noise characteristic value and can use dissipating of Fig. 4 a Penetrate figure distribution next schematically illustrate, Fig. 4 b then schematically compares true signal-to-noise characteristic value SNR0, and (transverse axis, can For logarithmic scale) and initial signal-to-noise characteristic value SNRi [k] (longitudinal axis can be logarithmic scale).Fig. 4 a with In the example of Fig. 4 b, (true, initial) signal-to-noise characteristic value may refer to signal to noise ratio.
Because the decision-making interval that the example of Fig. 4 b and Fig. 4 b uses fixed boundary divides D [p] (Fig. 4 a), Boundary Decision-making interval (at least coinciding with the decision-making interval of boundary B [p]) is at least more than star while growing Seat dot spacing is from a [p], the side of remaining decision-making interval (decision-making interval that side is not overlapped with boundary B [p]) Long then be equal to apart from a [p].
Shown in Fig. 4 b, special in initial signal-to-noise characteristic value SNRi [k] and the true noise of estimating circuit 28 output Correct (preferable) relation between value indicative SNR0 should be linear, as shown in straight line 600；But, solid Under the decision-making interval of deckle circle divides, initial signal-to-noise characteristic value SNRi [k] and true signal-to-noise characteristic value SNR0 Between relation but can curved 610, its reason can be described as follows.
In fig .4, the primary carrier s0 [k] of radiating circuit 10 is to be formed according to constellation point c [p, i0, q0]. If true signal-to-noise characteristic value SNR0 is equal to higher value h1 (Fig. 4 b), it is less to represent noise jamming, The decision-making interval d [i, p0, q0] that carrier wave s2 [k] after channel 12 transmission can fall around constellation point c [p, i0, q0] In, for example say and be in point z1；In this case, the correct interpretation of slicer 26 meeting goes out carrier wave s2 [k] is right Should be in constellation point c [p, i0, q0], when between constellation point c [p, i0, q0] that interpretation is gone out by estimating circuit 28 and point z1 When difference vector v1e is considered as noise to estimate initial signal-to-noise characteristic value SNRi [k], initial signal-to-noise characteristic value SNRi [k] also can be sufficiently close to true signal-to-noise characteristic value SNR0, as shown in the point b1 on Fig. 4 b.
If true signal-to-noise characteristic value SNR0 is a less value h2 (h2<H1), represent noise jamming larger, Can make carrier wave s2's [k] to be located away from the decision-making interval d [p, i0, q0] that original constellation point c [p, i0, q0] is located；Example As the position of carrier wave s2 [k] may drift to point z2, positioned at the decision-making interval of constellation point c [p, i2, q2] In d [p, i2, q2]；Therefore, slicer 26 can be judged carrier wave s2 [k] by accident and be corresponded to constellation point c [p, i2, q2]；According to According to the interpretation of slicer 26, estimating circuit 28 can be by the difference vector between constellation point c [p, i2, q2] and point z2 V2e is considered as noise to estimate initial signal-to-noise characteristic value SNRi [k], the point on forming curves 610 (Fig. 4 b) b2.However, because real original constellation point is c [p, i0, q0] rather than c [p, i2, q2], real noise should be Difference vector v2 between constellation point c [p, i0, q0] and point z2, rather than v2e.That is, initial signal-to-noise characteristic value The right value of SNRi [k] should point b20 on straight line 600.Because the length of vector v 2e is shorter than vector v 2, Initial signal-to-noise characteristic value SNRi [k] can be higher than true signal-to-noise characteristic value SNR0.On Fig. 4 b, point b2 with Gap between b20 closes the difference being connected between vector v 2e and v2.
If true signal-to-noise characteristic value SNR0 is less value h3 (h3<H2), represent noise jamming bigger, The decision-making interval d [p, i0, q0] of the position of carrier wave s2 [k] further from original constellation point c [p, i0, q0] can be made；For example, The position of carrier wave s2 [k] may drift to the point z3 in Fig. 4 a, positioned at the decision-making interval of constellation point c [p, i3, q3] In d [p, i3, q3].Therefore, slicer 26 can be judged carrier wave s2 [k] by accident and be corresponded to constellation point c [p, i3, q3]；According to According to the interpretation of slicer 26, estimating circuit can be by the difference vector v3e between constellation point c [p, i3, q3] and point z3 It is considered as the point b3 to estimate initial signal-to-noise characteristic value SNRi [k], on forming curves 610 for the noise.But, very Positive original constellation point is c [p, i0, q0] rather than c [p, i3, q3], the difference between constellation point c [p, i0, q0] and point z3 Vector v 3 could correctly reflect real noise, rather than vector v 3e；Initial signal-to-noise characteristic value SNRi [k] Right value should point a30 on straight line 400 and true signal-to-noise characteristic value SNR0 of coincideing.Because vector v 3e Length shorter than vector v 3, can be high by initial signal-to-noise characteristic value SNRi [k] that vector v 3e is considered as noise gained In true signal-to-noise characteristic value SNR0.On Fig. 4 b, the gap between point b3 and b30 is closed and is connected in vector v 3e Difference and between v3.Be can be seen that by Fig. 4 a, the difference between vector v 3e and v3 is more than vector v 2e and v2 Between difference, therefore the gap between point b3 and b30 be more than point b2 and b20 between gap.
If true signal-to-noise characteristic value SNR0 is less value h4 (h4<H3), represent noise jamming bigger, The position that carrier wave s2 [k] can be made, further from original constellation point c [p, i0, q0], drifts near boundary B [p]；Example As the position of carrier wave s2 [k] may drift to the point z4 in Fig. 4 a, positioned at the border of constellation point c [p, 1, q4] In decision-making interval d [p, 1, q4].Therefore, slicer 26 can be judged carrier wave s2 [k] by accident and be corresponded to constellation point c[p,1,q4]；According to the interpretation of slicer 26, estimating circuit can be by between constellation point c [p, 1, q4] and point z4 Difference vector v4e is considered as noise to estimate initial signal-to-noise characteristic value SNRi [k], the point on forming curves 610 b4.However, because real original constellation point is c [p, i0, q0] rather than c [p, 1, q4], constellation point c [p, i0, q0] Difference vector v4 and between point z4 could correctly reflect real noise, rather than vector v 4e；Initial noise The right value of characteristic value SNRi [k] should point a40 on straight 600 with true signal-to-noise characteristic value SNR0 of coincideing. Because the length of vector v 4e is shorter than vector v 4, according to initial signal-to-noise characteristic value SNRi [k] of vector v 4e gained It can be higher than true signal-to-noise characteristic value SNR0.As shown in Figure 4 b, the gap between point b4 and b40 is closed and is connected in Difference between vector v 4e and v4.
As shown in fig. 4 a, both decision-making interval d [p, i2, q2] and d [p, i3, q3] that point z2 and z3 is located are permissible It is not that Boundary Decision-making is interval, therefore vector v 2e is still limited by apart from a [p]/2 with the length of v3e.But, exist Under the decision-making interval of fixed boundary divides, Boundary Decision-making interval is at least long to be more than apart from a [p], so The length of vector v 4e is not limited by apart from a [p]/2, and so that initial signal-to-noise characteristic value SNRi [k] is reduced and relatively It is close to true signal-to-noise characteristic value SNR0, be also therefore less than in the longitudinal axis height of corresponding points b4 (Fig. 6 B) The longitudinal axis height of point b2 and b3.
That is, under the decision-making interval of fixed boundary divides, with true signal-to-noise characteristic value SNR0 by value h1 It is reduced to h2, h3 and h4, initial signal-to-noise characteristic value SNRi [k] can first be gradually distance from true signal-to-noise characteristic value SNR0 (as tendency between value h1 and h3 for the curve 610), then again can be towards true signal-to-noise characteristic value Close to (as tendency between value h3 to h4 for the curve 610), this is because larger-size side to SNR0 Boundary's decision-making interval has more space to reflect longer noise vector (as vector v 4e), makes noise vector not The less non-Boundary Decision-making of size can be limited to interval.
Continue Fig. 4 a, 4b, refer to Fig. 5；Under the decision-making interval of fixed boundary divides, if carrier wave s0 [k] Using modulation set ms [k] be BPSK, QPSK, 8QAM, 16QAM, 64QAM, 256QAM, 1024QAM or 4096QAM is to carry 1,2,3,4,6,8,10 or 12 bits within the unit interval Digital information, then (longitudinal axis, can be logarithmic scale to initial signal-to-noise characteristic value SNRi [k], as with decibel being Unit) between true signal-to-noise characteristic value SNR0 (transverse axis, can be logarithmic scale, such as in units of decibel) Relation can be rendered as curve 701,702,703,704,705,706,707 or 708 (curve respectively 701 almost overlap with 702)；Relatively, initial signal-to-noise characteristic value SNRi [k] and true signal-to-noise characteristic value Correct (preferable) relation between SNR0 answers linear 700 linear relationship.For example, when true noise When characteristic value SNR0 is equal to value u11, the right value of initial signal-to-noise characteristic value SNRi [k] should be equal to value h10； But, as shown in figure 5, under same true signal-to-noise characteristic value SNR0, modulation sets ms [k] in list The bit number carrying in the time of position is more, between initial signal-to-noise characteristic value SNRi [k] and true signal-to-noise characteristic value The gap of SNR0 is also bigger.For example, when true signal-to-noise characteristic value SNR0 is equal to value h10, if Modulation sets ms [k] for 256QAM to carry the symbol of 6 bits in time per unit, then initial noise Characteristic value SNRi [k] can mistakenly be over-evaluated for value h1a；If modulation set ms [k] be 4096QAM with The symbol of 12 bits is carried, then initial signal-to-noise characteristic value SNRi [k] can mistakenly be over-evaluated in time per unit For value h1b, and value h1b>h1a>h10.The bit number carrying within the unit interval is higher, adjacent constellation point Between beeline also can be shorter, the interval size of non-Boundary Decision-making also can be less；When true signal-to-noise characteristic value (it is greater than value u11), the noise vector ratio that estimating circuit 28 misestimates when the value of SNR0 is also not very too little It is easier in same non-Boundary Decision-making interval, non-Boundary Decision-making interval is less, and estimating circuit 28 carries For initial signal-to-noise characteristic value SNRi [k] more can be overestimated, the difference and between true signal-to-noise characteristic value SNR0 Away from also bigger.
On the other hand, when the value of true signal-to-noise characteristic value SNR0 is less (e.g., less than value u11), estimate The noise vector that meter circuit 28 misestimates is easier in Boundary Decision-making interval.As above once described in, Under the decision-making interval of fixed boundary divides, different default modulation set the non-border of MS [p1] and MS [p2] The decision-making interval length of side is respectively equal to constellation dot spacing from a [p1] and a [p2], and Boundary Decision-making interval at least Longer sides, its length of side is respectively greater than constellation dot spacing from a [p1] and a [p2].For example it is assumed that default adjust Set up and determine MS [p1] and MS [p2] respectively 256QAM and 4096QAM, the interval side of non-Boundary Decision-making Length is about 4 than a [p1] and a [p2]:1, but the interval longer sides length of Boundary Decision-making is generally equal.Therefore, when When truly miscellaneous characteristic value SNR0 of news is larger, gap of the initial signal-to-noise characteristic value under this two default modulation setting Larger (gap as between value h1a and h2a), because its length of side interval to non-Boundary Decision-making is more related, And the length of side in both non-Boundary Decision-making intervals has larger difference.On the other hand, if truly interrogating miscellaneous characteristic value SNR0 is less, this two default modulation set under initial signal-to-noise characteristic value gap is less and mutual convergence, Because the length of its longer sides interval to Boundary Decision-making is more related, and both Boundary Decision-makings interval is longer The difference in length on side is less.
In order to revise the difference of initial signal-to-noise characteristic value SNRi [k] and true signal-to-noise characteristic value SNR0, transmitting It is provided with correcting circuit 30 in circuit 30.Please once again with reference to Fig. 1；In radiating circuit 30, correcting circuit 30 Couple estimating circuit 28, can be each according to the numerical value of initial signal-to-noise characteristic value SNRi [k] of each carrier wave s1 [k] Carrier wave s1 [k] provides corresponding correction value r [k], and revises initial signal-to-noise characteristic value according to corresponding correction value r [k] SNRi [k], to produce one for each carrier wave s1 [k] to revise signal-to-noise characteristic value SNRc [k], to k=1 to K.
In one example, correcting circuit 30 may include a lookup table circuit 34 and a multiplier 32；Multiplier 32 Couple lookup table circuit 34 and correcting circuit 30.Continue Fig. 1, please also refer to Fig. 6, its illustrated that according to Form 800 according to the present invention one example.In one example of this case, the recordable form 800 of lookup table circuit 34, Set MS [p] for each default modulation and store multiple preset correction value e [p, 1] to e [p, N] (to p=1 to P), And the initial signal-to-noise characteristic value of ms [k], each carrier wave s1 [k] is set according to the corresponding modulating of each carrier wave s1 [k] SNRi [k] sets the preset correction value e [p, 1] to e [p, N] of MS [p] (to p=1 to P) with each default modulation And be that each carrier wave s1 [k] provides corresponding correction value r [k], to k=1 to K.Wherein, each default modulation sets Respectively this preset correction value e [p, n] of MS [p] is to close to be connected in multiple default signal-to-noise characteristic values SNRt [1] extremely One of them SNRt [n] of SNRt [N].In one embodiment, network system can only be set using a kind of modulation (i.e. K=1), for example default modulation sets MS [1]；Therefore, form 800 can only have a hurdle (column), Record preset correction value e [1,1] to e [1, N].
In one example, lookup table circuit 34 is to find out one by default modulation setting MS [1] to MS [P] to meet The default modulation that the corresponding modulation of carrier wave s1 [k] sets ms [k] (such as QPSK) sets MS [p1] (for example QPSK).In one example, lookup table circuit 34 can be by default signal-to-noise characteristic value SNRt [1] to SNRt [N] Seek obtaining a default letter closest to initial signal-to-noise characteristic value SNRi [k] (such as -3.6db) for carrier wave s1 [k] Characteristic value SNRt of making an uproar [n1] (such as -4db)；So, lookup table circuit 34 just sets MS [p1] according to default modulation To find out corresponding preset correction value e [p1, n1] right as carrier wave s1 [k] with default signal-to-noise characteristic value SNRt [n1] Answer correction value r [k].In another example, lookup table circuit 34 can be by default signal-to-noise characteristic value SNRt [1] to SNRt [N] In for carrier wave s1 [k] seek two upper and lower closest to initial signal-to-noise characteristic values SNRi [k] (such as -3.6db) Default signal-to-noise characteristic value SNRt [n1] on boundary and SNRt [n2] (such as -3db and -4db)；So, table look-up electricity Road 34 just can be set MS [p1] according to default modulation and be looked for SNRt [n2] with default signal-to-noise characteristic value SNRt [n1] Go out corresponding preset correction value e [p1, n1] and value e [p1, n2], and according to initial signal-to-noise characteristic value SNRi [k], Default signal-to-noise characteristic value SNRt [n1] of its bound is carried out with value e [p1, n2] to e [p1, n1] with SNRt [n2] Interpolative operation, and using the result after computing as carrier wave s1 [k] corresponding correction value r [k].
Repaiied with corresponding using initial signal-to-noise characteristic value SNRi [k] that estimating circuit 28 and lookup table circuit 34 provide On the occasion of r [k], initial signal-to-noise characteristic value SNRi [k] can be multiplied by this correspondence correction value by multiplier 32 (Fig. 1) R [k], and produce correction signal-to-noise characteristic value SNRc [k] according to product r [k] * SNRi [k].
Each preset correction value e [p, n] in form 800 (Fig. 6) can be calculated with numerical simulation to be tried to achieve.Citing For, to the initial noise being misestimated under fixed boundary decision-making interval divides in correction map 4b and Fig. 5 Characteristic value SNRi [k], can be equal to a certain default signal-to-noise characteristic value SNRt [n] in true signal-to-noise characteristic value SNR0 And modulation sets to simulate under conditions of ms [k] is equal to a certain default modulation setting MS [p] and (is such as superimposed by noise Property additive white Gaussian) the carrier wave s2 [k] that affects, and simulate slicer 26 and draw in fixed boundary decision-making interval Hard decision running and the signal-to-noise characteristic value to carrier wave s2 [k] and s3 [k] for the estimating circuit 28 to carrier wave s2 [k] under point Estimation running, simulates initial signal-to-noise characteristic value SNRi [k] produced by estimating circuit 28 according to this；So, Just preset correction value e [p, n] can be calculated according to ratio SNRt [n]/SNRi [k].
Be listed below an example of form 800, its be revise fixed boundary decision-making interval divide lower at the beginning of Beginning signal-to-noise characteristic value；In this example, preset modulation set MS [1] to MS [P] be respectively BPSK, QPSK, (quantity P can be equal to for 8QAM, 16QAM, 64QAM, 256QAM, 1024QAM and 4096QAM 8), default signal-to-noise characteristic value SNRt [1] is to arrange from small to large to SNRt [N], by -6 decibels to 41 points Shellfish (quantity N can be equal to 48).
Above table example also can be illustrated in Fig. 7, and its transverse axis is to preset signal-to-noise characteristic value SNRt [1] extremely SNRt [N] (can be logarithmic scale, such as in units of decibel), the longitudinal axis represents each preset correction value e [p, n] Value (can be linear-scale)；In Fig. 7, curve 901 illustrates that default modulation sets MS [1] (i.e. BPSK the preset correction value e [1,1] to e [1, N]) being correlated, curve 902 illustrates that default modulation sets The preset correction value e [2,1] to e [2, N] that MS [2] (i.e. QPSK) is correlated, curve 903 illustrates that pre- If modulation sets the preset correction value e [3,1] to e [3, N] that MS [3] (i.e. 8QAM) is correlated, curve 904 Illustrate that default modulation sets the preset correction value e [4,1] to e [4, N] that MS [4] (i.e. 16QAM) is correlated, Curve 905 illustrates that default modulation sets the preset correction value e [5,1] that MS [5] (i.e. 64QAM) is correlated To e [5, N], it is pre- that curve 906 illustrates that default modulation setting MS [6] (i.e. 256QAM) is correlated If correction value e [6,1] is to e [6, N], curve 907 illustrates that default modulation sets MS [7] (i.e. 1024QAM) The preset correction value e [7,1] to e [7, N] being correlated, what curve 908 was illustrated is then that default modulation sets MS [8] The preset correction value e [8,1] to e [8, N] that (i.e. 4096QAM) is correlated.
Be can be seen that with Fig. 7 by above table example, with default signal-to-noise characteristic value SNRt [1] to SNRt [N] Arrange from small to large, in the preset correction value e [p, 1] to e [p, N] of same default modulation setting MS [p] at least Fractional numbers preset correction value can be in first one first growth trend change (such as monotone decreasing or strictly pass Subtract), then in one second growth trend change (such as monotonic increase or strictly increasing), and this first increase and decrease Trend is contrary with this second growth trend.If the skew of initial signal-to-noise characteristic value SNRi [k] is larger, correction electricity Road 30 (Fig. 1) will be from the less preset correction value e [p, n] of numerical value as corresponding correction value r [k], ability With multiplier 32, larger initial signal-to-noise characteristic value SNRi [k] is taken advantage of as less correction signal-to-noise characteristic value SNRc[k].Therefore, greatly SNRt [N], at least fractional numbers are become with default signal-to-noise characteristic value SNRt [1] Individual preset correction value e [p, n] from large to small (decrescence) first, then can change from small to big (cumulative).
In the example of above table and Fig. 7, set MS [1] to MS [P] in unit with default modulation The interior bit number carrying arranges from small to large, is connected in same default signal-to-noise characteristic value SNRt [n] in pass and belongs to In the preset correction value e [1, n] to e [P, n] that different default modulation set, at least fractional numbers meeting presents Trend decrescence.For example, under same default signal-to-noise characteristic value SNRt [12], preset correction value e [1,12] It is in decrescence trend to e [8,12].Similarly, under same default signal-to-noise characteristic value SNRt [21], preset and repair It is in decrescence trend on the occasion of e [1,21] to e [8,21].As shown in figure 5, in same true signal-to-noise characteristic value SNR0 Under (such as value h1), carry the more default modulation of bit number in the unit interval and set MS [p1] (as song The 4096QAM of line 708) understand default modulation setting MS [p2] more less than bit number (as curve 706 256QAM) further from true signal-to-noise characteristic value SNR0, therefore in the unit interval, carry more the presetting of bit number Modulation sets MS [p1] needs less default signal-to-noise characteristic value e [p1, n] of numerical value to do more when taking advantage of calculation Under repair.Continue above table and Fig. 7, refer to Fig. 8, it is illustrated that uncorrected initial noise Correction signal-to-noise characteristic value SNRc [k] after characteristic value SNRi [k] and correction, its transverse axis connects for receiving circuit 20 True signal-to-noise characteristic value SNR0 (can be logarithmic coordinates, unit is decibel) in time receiving, the longitudinal axis then represents just Beginning signal-to-noise characteristic value SNRi [k] or the value revising signal-to-noise characteristic value SNRc [k].If receiving circuit 20 is foundation Estimating signal-to-noise characteristic value, then this signal-to-noise characteristic value is to true for the reception of probe packets (sounding packet) The variation relation of real signal-to-noise characteristic value SNR0 can be illustrated by curve 1000；Because the content of probe packets is to connect Receive what circuit 20 can be learnt in advance, therefore curve 1000 can represent the ideal case of signal-to-noise characteristic value estimation.Phase Over the ground, if receiving circuit 20 is to estimate initial noise according to the reception of data frame (data frame) Characteristic value SNRi [k], then initial signal-to-noise characteristic value SNRi [k] can to the relation of true signal-to-noise characteristic value SNR0 Represented by curve 1001；Because the digital information in data frame is that receiving circuit 20 cannot be learnt in advance, Therefore initially signal-to-noise characteristic value SNRi [k] can mistakenly be overestimated, and makes curve 1001 more deflection curve 1000. Compare down, what curve 1002 was illustrated is then the correction signal-to-noise characteristic value after calibrated circuit 30 compensates The relation to true signal-to-noise characteristic value SNR0 for the SNRc [k]；As seen from Figure 8, compared to curve 1001 Initial signal-to-noise characteristic value, the correction signal-to-noise characteristic value of curve 1002 can very convergence curve 1000, represent school Positive circuit 30 can revise the initial signal-to-noise characteristic value being misestimated really, so that correction signal-to-noise characteristic value convergence is managed Think situation.
Please once again with reference to Fig. 1.In advanced modernization network system, can estimate according to receiving circuit 20 Signal-to-noise characteristic value adaptively to adjust signal transmitting and/or the running receiving.Application in receiving circuit 20 Circuit 36 can assist above-mentioned adaptability to transport according to revising signal-to-noise characteristic value SNRc [1] to SNRc [K] Make.For example, application circuit 36 may include a bit load initialization circuit 38, couples correcting circuit 30, In order to update the corresponding modulating of each carrier wave s0 [k] according to correction signal-to-noise characteristic value SNRc [k] of each carrier wave s1 [k] Set ms [k], to k=1 to K.Corresponding modulating after renewal sets ms [k] and can be returned by feedback signal s4 Award to radiating circuit 10, and radiating circuit 10 just can set ms [k] in each load according to the corresponding modulating after updating Following digital information is carried on ripple s0 [k].For example it is assumed that radiating circuit 10 first adopts a certain default tune Set up corresponding modulating setting ms [k] determining MS [p1] as carrier wave s0 [k], if receiving circuit 20 is after the receipt Draw correction signal-to-noise characteristic value SNRc [k] of numerical value preferably (higher), represent channel 12 in information instantly Transmission is all right, therefore bit load initialization circuit 38 notice capable of feedback radiating circuit 10, make radiating circuit 10 change corresponding modulating setting ms [k] adopting another default modulation setting MS [p2] as carrier wave s0 [k]；Wherein, The bit number (i.e. bit load) that default modulation setting MS [p2] carried within the unit interval can be higher than previously to adopt Default modulation sets MS [p1].So, the flow of information transfer just can effectively be increased (throughput).For example, receiving circuit 20 can be to radiating circuit 10 feedback one frequency modulation collection of illustrative plates (tone-map), it can describe the corresponding modulating that carrier wave s0 [1] to s0 [K] should adopt and set ms [1] extremely ms[K].
Relatively, if receiving circuit 20 draws the correction signal-to-noise characteristic of numerical value poor (relatively low) after the receipt Value SNRc [k], it is out of condition in information transfer instantly to represent channel 12, therefore bit load initialization circuit 38 notice radiating circuits 10 capable of feedback, make radiating circuit 10 can continue to use and previously preset modulation setting MS [p1], Or change adopt another default modulation set MS [p3], using as carrier wave s0 [k] corresponding modulating set ms [k]；Its In, the bit load presetting modulation setting MS [p3] can set MS [p1] less than the previous default modulation adopting. So, just it is avoided that strong noise affects the correctness of numerical data transmission.
But, the premise of above-mentioned adaptability running is that the signal-to-noise characteristic value that receiving circuit 30 is estimated must be close to True signal-to-noise characteristic value；If the signal-to-noise characteristic value that receiving circuit 30 estimates and the difference of true signal-to-noise characteristic value Different excessive, network system can affect network system on the contrary according to the adaptability running that estimation signal-to-noise characteristic value is carried out The correct running of system.For example, if the bit load initialization circuit 38 in application circuit 36 is based on Initial signal-to-noise characteristic value SNRi [k] and non-modified signal-to-noise characteristic value SNRc [k], due to initial signal-to-noise characteristic value SNRi [k] can compare for optimism and be higher than true signal-to-noise characteristic value, therefore bit load initialization circuit 38 can make by mistake Radiating circuit 10 changes adopts the higher modulation setting of bit load to increase the flow of information transfer；Though information passes Defeated flow is high, but error rate also can be higher, because the signal s1 [k] that receiving circuit 20 really receives is in fact Disturbed by strong noise, can the information content of correct effectively transmission be reduced on the contrary.
It is not limited to adaptability bit load characteristic, the signal-to-noise characteristic value that receiving circuit 20 is estimated can be additionally used in it His advanced function, seems soft bit (soft-bit) decoding, soft decision (soft-decision) decoding, adapts to Property modulation with coding (AMC, adaptive modulation and coding), turbine (turbo) decoding and / or dynamic power control etc.；These advanced functions are required for excellent signal-to-noise characteristic value estimation could be correctly effective Ground running.Just can met these through revised signal-to-noise characteristic value SNRc [k] of revising of correcting circuit 30 of the present invention Needed for advanced function；Accordingly, in Fig. 1, application circuit 36 may also comprise the electricity supporting above-mentioned advanced function Road, for example, say it is soft bit decoding circuit (not shown) etc., it can couple correcting circuit 30, to use school Correction signal-to-noise characteristic value SNRc [k] that positive circuit 30 produces.
Continue Fig. 1, refer to Fig. 9, it is illustrated that the flow process 1200 according to the present invention one example；Figure Receiving circuit 20 in 1 can implementing procedure 1200 be estimated with revising signal-to-noise characteristic value.Flow process 1200 main Step can be described as follows.
Step 1202：There is provided an equilibrium by the balanced device 24 in receiving circuit 20 according to receipt signal s1 Signal s2.Wherein, receipt signal s1 comprises the individual carrier wave s1 [1] of K (more than or equal to 1) to s1 [K], and in Each carrier wave s1 [k] is upper to carry corresponding digital information according to corresponding modulating setting ms [k]；Corresponding modulating sets Ms [k] is then to set MS [1] to selected in MS [P] by the individual default modulation of P (more than or equal to 1).Equilibrium Device 24 can carry out equilibrium running to each carrier wave s1 [k], to produce the carrier wave s2 [k] in equalizing signal s2.
Step 1204：Carry out one by slicer 26 and cut step, respectively to be carried by interpretation in this equalizing signal s2 Digital information smb [k] that ripple s1 [k] carries, and provide one to cut signal s3 according to this, it includes carrier wave s3 [1] To s3 [K].For example, if the corresponding modulating of carrier wave s2 [k] sets ms [k] and meets default modulation setting MS [p], then slicer 26 can be using decision-making interval division D [p] shown in Fig. 3, with according to carrier wave s2 [k] Position judgment on scatter diagram goes out the decision-making interval d [p, i, q] that it is located in, and the number that carrier wave s2 [k] is carried Word information smb [k] interpretation is the presupposed information SMB [p, i, q] corresponding to connection constellation point c [p, i, q], to reflect In carrier wave s3 [k].As discussed earlier (as Fig. 3), the decision-making interval that slicer 26 adopts divides D [p] It can be the decision-making interval division of fixed boundary.
Step 1206：One estimating step is carried out by estimating circuit 28, with according to equalizing signal s2 with cut letter The difference of number s3 is that each carrier wave s1 [k] provides initial signal-to-noise characteristic value SNRi [k].For example, if cutting Carrier wave s2 [k] interpretation is constellation point c [p, i, q] by device 26, and estimating circuit 28 can be according to carrier wave s2 [k] and constellation Scatter diagram difference vector between point c [p, i, q] estimates initial signal-to-noise characteristic value SNRi [k].
Step 1208：One aligning step is carried out by correcting circuit 30, with the initial letter according to each carrier wave s1 [k] The numerical value of characteristic value SNRi of making an uproar [k] provides corresponding correction value r [k], and repaiies according to the correspondence of each carrier wave s1 [k] Revise initial signal-to-noise characteristic value SNRi [k] of each carrier wave s1 [k] on the occasion of r [k], to produce for each carrier wave s1 [k] One revises signal-to-noise characteristic value SNRc [k].For example.Can be that each default modulation sets by lookup table circuit 34 The individual preset correction value e [p, 1] to e [p, N] of MS [p] storage N (more than 1), and right according to each carrier wave s1 [k] Setting ms [k], initial signal-to-noise characteristic value SNR [k] of each carrier wave s1 [k] and each default modulation should be modulated set The preset correction value e [1,1] to e [P, N] of MS [1] to MS [P] and be that each carrier wave s1 [k] provides corresponding correction value r[k]；And, initial signal-to-noise characteristic value SNRi [k] of each carrier wave s1 [k] is multiplied by by each carrier wave by multiplier 32 Corresponding correction value r [k] of s1 [k], produces correction signal-to-noise characteristic value SNRc [k] of each carrier wave s1 [k] according to this.Its In, each preset correction value e [p, n] that each default modulation sets MS [p] is to close to be connected in N number of default signal-to-noise characteristic Value SNRt [1] to SNRt [N] one of them SNRt [n].
When lookup table circuit 34 is that each carrier wave s1 [k] provides corresponding correction value r [k], it is to be set by default modulation Find out in MS [1] to MS [P] and set, with corresponding modulating, default modulation setting MS [p] that ms [k] is consistent, and By seeking in default signal-to-noise characteristic value SNRt [1] to SNRt [N], to obtain an initial noise with each carrier wave s1 [k] special Immediate default signal-to-noise characteristic value SNRt [n] of value indicative SNRi [k], to set the pre- of MS [p] in default modulation If the preset correction value e [p, n] that default signal-to-noise characteristic value SNRt [n] is correlated to e [p, N] by correction value e [p, 1] Corresponding correction value r [k] as each carrier wave s1 [k].
Flow process 1200 can be implemented with any combination of hardware, software, firmware or three.For example, Step 1208 can be implemented with the correcting circuit 30 of hardware, and lookup table circuit 34 may include static random-access and deposits Reservoir (SRAM) is to store form 800 (Fig. 6)；Or, step 1208 (can not schemed by processor Show) execute software and/or firmware to implement, and form is stored with dynamic random access memory (DRAM) 800.
In summary, the present invention can improve the estimation to signal-to-noise characteristic value for (correction) receiving terminal；For example, connect Receiving end can mistakenly over-evaluate signal-to-noise characteristic value because of the running of the hard decision of slicer, and the technology of the present invention then can be fitted Locality will be repaiied under the initial signal-to-noise characteristic value over-evaluated as more correctly revising signal-to-noise characteristic value, make network system According to correction signal-to-noise characteristic value come the communication that to correctly judge (such as channel) situation, and correctly can be fitted The transmitting-receiving adjustment of answering property, for example, say that the bit load being to adjust each carrier wave sets.
Although the present invention is disclosed as above with preferred embodiment, so it is not limited to the present invention, Ren Heben Skilled person, without departing from the spirit and scope of the present invention, when a little modification and perfect can be made, Therefore protection scope of the present invention is when by being defined that claims are defined.

Claims (15)

1. a kind of receiving circuit revising the estimation of signal-to-noise characteristic value, comprises：
One balanced device, provides an equalizing signal (equalized signal) according to a receipt signal；
One slicer, couples this balanced device, provides one to cut signal (sliced signal) according to this equalizing signal；
One estimating circuit, couples this balanced device and this slicer, in order to cut letter according to this equalizing signal with this Number difference provide an initial signal-to-noise characteristic value；And
One correcting circuit, couples this estimating circuit, provides a corresponding correction value according to this initial signal-to-noise characteristic value, And produce a correction signal-to-noise characteristic value according to this corresponding correction value and this initial signal-to-noise characteristic value.
2. receiving circuit as claimed in claim 1 is it is characterised in that this correcting circuit comprises：
One lookup table circuit, stores multiple preset correction value, and pre- with the plurality of according to this initial signal-to-noise characteristic value If correction value provides this correspondence correction value；Wherein, respectively this preset correction value corresponds to multiple default noises spies One of them of value indicative；And
One multiplier, couples this lookup table circuit and this estimating circuit, this initial signal-to-noise characteristic value is multiplied by this right Correction value is answered to produce this correction signal-to-noise characteristic value.
3. receiving circuit as claimed in claim 2 is it is characterised in that this lookup table circuit is to be repaiied by the plurality of presetting On the occasion of in seek its corresponding default signal-to-noise characteristic value of a preset correction value closest to this initial signal-to-noise characteristic value This correspondence correction value to be provided.
4. receiving circuit as claimed in claim 2 it is characterised in that with the plurality of default signal-to-noise characteristic value by Little to longer spread, corresponding the plurality of preset correction value at least fractional numbers meeting is in first one first increase and decrease Long-term change trend, then in one second growth trend change, and this first growth trend and this second growth trend phase Instead.
5. receiving circuit as claimed in claim 4 it is characterised in that this one first growth trend be strictly decreasing, This second growth trend is strictly increasing.
6. receiving circuit as claimed in claim 1 is it is characterised in that this correcting circuit is more according to this receipt signal A modulation set this corresponding correction value be provided.
7. receiving circuit as claimed in claim 2 is it is characterised in that this lookup table circuit is more according to this receipt signal A modulation set this corresponding correction value be provided；Respectively this preset correction value corresponds to multiple default signal-to-noise characteristics One of value, corresponding to same default signal-to-noise characteristic value and multiple corresponding to different default modulation settings In preset correction value, it is set in the bit number carrying in the unit interval from small to large with the plurality of default modulation Arrangement, at least fractional numbers preset correction value can assume trend decrescence.
8., as the receiving circuit of claim 6, further include：
One bit load (bit loading) initialization circuit, couples this correcting circuit, special according to this correction noise Value indicative produces a feedback signal a to radiating circuit, is set with this modulation updating this receipt signal.
9. a kind of method that can revise the estimation of signal-to-noise characteristic value in a receiving circuit, comprises：
There is provided an equalizing signal (equalized signal) according to the receipt signal that this receiving circuit is received；
One is provided to cut signal according to this equalizing signal；
There is provided an initial signal-to-noise characteristic value according to the difference that this equalizing signal cuts signal with this；
There is provided a corresponding correction value according to this initial signal-to-noise characteristic value；And
Produce a correction signal-to-noise characteristic value according to this corresponding correction value and this initial signal-to-noise characteristic value.
10. method as claimed in claim 9 is it is characterised in that provide this right according to this initial signal-to-noise characteristic value The step answering correction value further includes：
There is provided this corresponding correction value according to this initial signal-to-noise characteristic value with multiple preset correction value；Wherein, respectively should Preset correction value corresponds to one of them of multiple default signal-to-noise characteristic values.
11. as claim 10 method it is characterised in that according to this initial signal-to-noise characteristic value with the plurality of Preset correction value provides the step of this correspondence correction value to further include：
By seek in the plurality of preset correction value its corresponding default signal-to-noise characteristic value of a preset correction value connects most This initial signal-to-noise characteristic value nearly is providing this correspondence correction value.
12. such as claim 10 method is it is characterised in that with the plurality of default signal-to-noise characteristic value by little To longer spread, corresponding the plurality of preset correction value at least fractional numbers meeting is in first that one first increase and decrease becomes Gesture changes, then in one second growth trend change, and this first growth trend is contrary with this second growth trend.
13. as claim 12 method it is characterised in that this one first growth trend be strictly decreasing, This second growth trend is strictly increasing.
14. such as claim 10 method is it is characterised in that pre- with multiple according to this initial signal-to-noise characteristic value If correction value provides the step of this correspondence correction value to further include：
More setting according to a modulation of this receipt signal provides this corresponding correction value.
15. as claim 14 method it is characterised in that respectively this preset correction value correspond to multiple pre- If one of them of signal-to-noise characteristic value, corresponding to same default signal-to-noise characteristic value and corresponding to different default modulation In the multiple preset correction value setting, it is set in, with the plurality of default modulation, the bit carrying in the unit interval Number arranges from small to large, and at least fractional numbers preset correction value can assume trend decrescence.
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Publication number Priority date Publication date Assignee Title
CN102664859A (en) * 2012-05-22 2012-09-12 天津工业大学 Synchronization and channel estimation scheme for multi-band orthogonal frequency division multiplexing (OFDM) ultra wideband receiver
WO2013125174A1 (en) * 2012-02-20 2013-08-29 日本電気株式会社 Device for processing received signal, and method for processing received signal
CN103532905A (en) * 2012-07-05 2014-01-22 北京新岸线移动通信技术有限公司 Signal-to-noise-ratio estimation method and device based on hard decisions

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013125174A1 (en) * 2012-02-20 2013-08-29 日本電気株式会社 Device for processing received signal, and method for processing received signal
CN102664859A (en) * 2012-05-22 2012-09-12 天津工业大学 Synchronization and channel estimation scheme for multi-band orthogonal frequency division multiplexing (OFDM) ultra wideband receiver
CN103532905A (en) * 2012-07-05 2014-01-22 北京新岸线移动通信技术有限公司 Signal-to-noise-ratio estimation method and device based on hard decisions

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