CN102421109B - Energy detection method and energy detection circuit applying same - Google Patents
Energy detection method and energy detection circuit applying same Download PDFInfo
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- CN102421109B CN102421109B CN201010299864.XA CN201010299864A CN102421109B CN 102421109 B CN102421109 B CN 102421109B CN 201010299864 A CN201010299864 A CN 201010299864A CN 102421109 B CN102421109 B CN 102421109B
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Abstract
The invention discloses an energy detection method and an energy detection circuit applying the same. A signal starting time point corresponding to an input signal is found out by referring a digital signal corresponding to the input signal. The energy detection method comprises the following steps of: sampling the digital signal to find out an ith sampling value; then caching (i-(M+N-1))th to (i-N)th sampling values and (i-(N-1))th to ith sampling values; setting a weighting parameter with a starting value; finding out a first parameter according to the weighting parameter and the (i-(M+N-1))th to (i-N)th sampling values; finding out a second parameter according to the (i-(N-1))th to ith sampling values; and comparing the first parameter with the second parameter, and judging that a sampling time point corresponding to the (i-(N-1))th sampling value is the signal starting time point when the second parameter is more than the first parameter. The energy detection method and energy detection circuit disclosed by the invention have the advantages of capability of adaptively dynamically regulating energy detection threshold, noise resisting capacity and higher accuracy rate of energy detection.
Description
Technical field
The present invention relates to a kind of energy detection method and energy measuring circuit.
Background technology
Flourish along with radio communication and application, time-sharing and multitask system is widely used in communication system, such as TCM Long Term Evolution communication protocol (Time Division Duplex Long TermEvolution, TD-LTE), global intercommunication microwave is processed communication protocol (Worldwide Interoperability forMicrowave Access, and the communication protocol such as international motor and electronic engineering association (Institute of Electricaland Electronics Engineers, IEEE) 802.16m agreement WiMAX).
In general, taking frame (Frame) structure in basic communication system, receiver cannot be learnt intensity and the characteristic of signal in the time starting to receive signal.So, existing communication system easily produces the situation of signal amplitude distortion at receiver, utilizes characteristics of signals to do synchronously that the mechanism of (Synchronization) makes a mistake and skew etc. and may further cause.Traditionally, it is the original position (being the initial time point of frame structure) of utilizing energy detection method to find signal to occur, receiver can be opened in the correct time its automatic gain control mechanism (Automatic Gain Control accordingly, AGC) carry out signal strength signal intensity adjustment, make whereby characteristics of signals not be destroyed and realize synchronization action more accurately.
In the prior art, energy detection method is to be set with fixing energy threshold (Energy Threshold), and in the time that the energy of input signal is greater than this threshold value, judges the initial time position that input signal occurs.
Summary of the invention
Technical problem to be solved by this invention is to propose a kind of energy detection method and energy measuring circuit, compared to conventional energy detection method, the energy detection method that the present invention is relevant and energy measuring circuit have advantages of that energy detection threshold is dynamically adjusted in adaptive ground, noise resisting ability accuracy better and energy measuring is higher.
This enforcement example proposes a kind of energy measuring circuit, is applied in receiver, with the digital signal with reference to corresponding with input signal, finds out the initial time point of signal that input signal is corresponding.Energy measuring circuit comprises value switch, offset buffer, first, second arithmetic unit, comparator and processor.Value switching response is conducting in control signal, and so that i sampling value of digital signal to be provided in i sampling time point, wherein i is greater than 1 natural number.Offset buffer buffer memory i-(M+N-1) pen is to i sampling value, and wherein M and N are greater than 1 natural number.Offset buffer comprises first and second sliding window value device, its respectively buffer memory i-(M+N-1) pen to i-N sampling value and i-(N-1) pen to i sampling value.First and second arithmetic unit is found out the first parameter according to weighting parameters and i-(M+N-1) pen to i-N sampling value respectively, and finds out the second parameter according to i-(N-1) pen to i sampling value.Comparator is first and second parameter relatively, and in the time that the second parameter is greater than the first parameter, provides energy measuring whole signal.Processor is set weighting parameters and is had initial value, more judges whether to receive energy measuring signal; The sampling time point that processor judging in the time receiving energy measuring signal corresponds to i-(N-1) sampling value is the initial time point of signal.Processor more judges that whether the simultaneous operation of this digital signal is successful, if so, calculates the signal noise ratio (Signal toNoise Ratio, SNR) of input signal, and sets according to this weighting parameters.Processor more provides control signal in the time that the second parameter is not more than the first parameter, to drive value switch that i+1 sampling value is provided.
Wherein, this processor more judges the whether success of simultaneous operation of this signal, and in the time of the simultaneous operation success of this signal, this processor calculates a signal noise ratio of this input signal, and sets according to this this weighting parameters; Wherein, this processor more provides this control signal in the time that this second parameter is not more than this first parameter, to drive this value switch that i+1 sampling value is provided.
Wherein, this offset buffer more comprises an overflow buffer, in order to buffer memory one i-(M+N) sampling value.
Wherein, this first arithmetic device comprises: a buffer, adds total value in order to buffer memory one i-(M+N) pen to one first of i-(N+1) sampling value; One adder, in order to this first is added to total value and deduct this i-(M+N) sampling value, and adds this i-N sampling value, adds total value to find out this i-(M+N-1) pen to one second of this i-N sampling value; One divider, in order to this second is added to total value divided by numerical value M, to obtain this operational parameter; And a multiplier, in order to obtain this first parameter according to this operational parameter and this weighting parameters computing.
Wherein, this second arithmetic device comprises: a buffer, adds total value in order to this i-N pen of buffer memory to one first of this i-1 sampling value; One adder, in order to this first is added to total value and deduct this i-N sampling value, and adds this i sampling value, adds total value to find out this i-(N-1) pen to one second of this i sampling value; And a divider, in order to this second is added to total value divided by numerical value of N, to obtain this second parameter.
Wherein, this second arithmetic device more comprises: a counter switch, is coupled between this divider and this comparator, in order to conducting in the time that i is more than or equal to M+N, to provide this second parameter to this comparator.
Wherein, when simultaneous operation when failure of this signal, this processor judges that this sampling time point is the false judgment event that is operating as of the initial time point of this signal, and this processor more increases the numerical value of this weighting parameters; Wherein, this first arithmetic device is found out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of increasing after operation, this first parameter and this second parameter after this comparator relatively upgrades accordingly, and in the time that this second parameter is greater than this first parameter after renewal, provide the signal of the energy measuring after a renewal; Wherein, this processor judges whether to receive the energy measuring signal after this renewal more constantly, and when energy measuring signal after receiving this renewal, judges the whether success of simultaneous operation of this signal.
Wherein, when simultaneous operation when success of this signal, this processor calculates this signal noise ratio of this input signal, and sets according to this this weighting parameters.
Wherein, in the time not receiving this energy measuring signal, this processor downgrades the numerical value of this weighting parameters; Wherein, this first arithmetic device is found out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of downgrading after operation, this first parameter and this second parameter after this comparator relatively upgrades accordingly, and in the time that this second parameter is greater than this first parameter after renewal, provide the signal of the energy measuring after a renewal; Wherein, this processor judges whether to receive the energy measuring signal after this renewal more constantly, and when energy measuring signal after receiving this renewal, judges the whether success of simultaneous operation of this signal.
Wherein, when simultaneous operation when success of this signal, this processor calculates this signal noise ratio of this input signal, and sets according to this this weighting parameters.
Separately propose a kind of energy detection method according to this enforcement example, be applied in receiver, to find out with reference to the digital signal corresponding with input signal the initial time point of signal that input signal is corresponding.Energy detection method comprises following step.First in sampling time point, digital signal is sampled, to find out i sampling value, wherein i is greater than 1 natural number.Then buffer memory i-(M+N-1) pen is to i-N sampling value, and buffer memory i-(N-1) pen is to i sampling value, and wherein M and N are greater than 1 natural number.Then set weighting parameters and there is initial value.Then find out the first parameter according to weighting parameters and i-(M+N-1) pen to i-N sampling value, and find out the second parameter according to i-(N-1) pen to i sampling value.Then first and second parameter relatively, and energy measuring signal is provided in the time that the second parameter is greater than the first parameter, judges that the sampling time point that corresponds to i-(N-1) sampling value is the initial time point of signal.Then judge whether to receive energy measuring signal, if judge that whether the simultaneous operation of digital signal is successful.When simultaneous operation when success of digital signal, calculate the signal noise ratio of input signal, and set according to this weighting parameters.
Wherein, the method more comprises: when simultaneous operation when failure of this signal, judge that this sampling time point is the false judgment event that is operating as of the initial time point of this signal, and increase the numerical value of this weighting parameters; Find out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of increasing after operation; This first parameter and this second parameter after relatively upgrading, and in the time that this second parameter is greater than this first parameter after renewal, provide the signal of the energy measuring after a renewal; Relatively this first and this second parameter, to judge whether this second parameter is greater than this first parameter; In the time that this second parameter is greater than this first parameter, energy measuring signal after a renewal is provided, to indicate this sampling time point as the initial time point of this signal, and judge the whether success of simultaneous operation of this signal; And when simultaneous operation when success of this signal, calculate this signal noise ratio of this input signal, and set according to this this weighting parameters.
Wherein, the method more comprises: in the time that this second parameter is not more than this first parameter, downgrade the numerical value of this weighting parameters; Find out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of downgrading after operation; This first parameter and this second parameter after relatively upgrading, and in the time that this second parameter is greater than this first parameter after renewal, provide energy measuring signal after a renewal to indicate this sampling time point as the initial time point of this signal, and judge the whether success of simultaneous operation of this signal; And when simultaneous operation when success of this signal, calculate this signal noise ratio of this input signal, and set according to this this weighting parameters.
Wherein, the method more comprises buffer memory one i-(M+N) sampling value.
Wherein, comprise according to this weighting parameters and this i-(M+N-1) the step of finding out this first parameter to this i-N sampling value: this i-(M+N) pen to one first of i-(N+1) sampling value of buffer memory adds total value; This first is added to total value and deduct this i-(M+N) sampling value, and add this i-N sampling value, add total value to find out this i-(M+N-1) pen to one second of this i-N sampling value; And this second is added to total value divided by numerical value M, to obtain this first parameter.
Wherein, the step of finding out this second parameter according to this i-(N-1) pen to this i sampling value comprises: this i-N pen of buffer memory to one first of this i-1 sampling value adds total value; This first is added to total value and deduct this i-N sampling value, and add this i sampling value, add total value to find out this i-(N-1) pen to one second of this i sampling value; And this second is added to total value divided by numerical value of N, to obtain this second parameter.
Energy detection method of the present invention and energy measuring circuit have advantages of that energy detection threshold is dynamically adjusted in adaptive ground, noise resisting ability accuracy better and energy measuring is higher.
Describe the present invention below in conjunction with the drawings and specific embodiments, but not as a limitation of the invention.
Brief description of the drawings
Fig. 1 illustrates the calcspar of the receiver of application the present embodiment;
Fig. 2 illustrates the calcspar according to the energy measuring circuit of the present embodiment;
Fig. 3 A to 3C illustrates the flow chart according to the energy detection method of the present embodiment;
Fig. 4 illustrates the schematic diagram that the signal noise ratio of weighting parameters K and input signal Si is tabled look-up.Wherein, Reference numeral:
100: signal receiver
102: antenna
104: gain amplifier
106: frequency synthesizer
108: analog filter
110: analog-digital converter
112: automatic gain controller
1: energy measuring circuit
12: value switch
14: offset buffer
16,18: arithmetic unit
20: comparator
22: processor
14a, 14b: sliding window value device
14c: overflow buffer
Ra1-raM, rb1-rbN: buffer unit
16a, 18a: buffer
16b, 18b: adder
16c, 18c: divider
16d: counter switch
18d: multiplier
Embodiment
Please refer to Fig. 1, it illustrates the calcspar of the receiver of application the present embodiment.The energy measuring circuit 1 of the present embodiment is for example applied in signal receiver 100, so that the input signal Si receiving is carried out to energy measuring operation.For instance, receiver 100 comprises antenna 102, gain amplifier 104, frequency synthesizer 106, analog filter 108 and analog-digital converter 110, aforementioned circuit receives input signal Si, and the processing that it is correlated with, to produce accordingly the digital signal R that wants to carry out energy measuring operation.
The energy measuring circuit of the present embodiment detects the original position (being the initial time point of the frame structure (Frame Structure) of input signal) of the signal appearance of input signal Si according to digital signal R.The signal receiver 100 of the energy measuring circuit of application the present embodiment for example comprises automatic gain controller (Auto GainControl) 112, the original position that the signal of its reference-input signal Si occurs, to gain amplifier 104 control that gains.Signal receiver 100 more comprises that other signal processing circuit is (such as interpolation device (Interpolator), root-raised cosine (Square Root Raised Cosine, SRRC) filter and fast Fourier industry transducer (Fast Fourier Transform, FFT)), to carry out other processing for input signal Si.Next be for example, the energy measuring circuit of the present embodiment is described further.
Please refer to Fig. 2, it illustrates the calcspar according to the energy measuring circuit of the present embodiment.Energy measuring circuit 1 comprises value switch 12, offset buffer 14, arithmetic unit 16,18, comparator 20 and processor 22.Value switch 12 is conducting in response to control signal Ec, and to provide digital signal R to offset buffer 14 in i sampling time point, and by i the sampling value Ri input offset buffer 14 of digital signal R, wherein i is greater than 1 natural number.
Offset buffer 14 has M+N buffer unit, carries out buffer memory in order to the sampling value that value switch 12 is provided, M+N the sampling value providing with buffer memory value switch 12, and wherein M and N are greater than 1 integer.Offset buffer 14 for example comprises sliding window value device 14a and 14b, its have respectively M buffer unit ra1, ra2 ..., raM and N buffer unit rb1, rb2 ..., rbN.Buffer unit ra1 to raM difference buffer memory i-(M+N-1) pen in sliding window value device 14a is to i-N sampling value Ri-(M+N-1) to Ri-N; Buffer unit rb1 to rbN difference buffer memory i-(N-1) pen in sliding window value device 14b is to i sampling value Ri-(N-1) to Ri.For instance, i equals numerical value M+N, and in buffer unit ra1 to raM, stores respectively sampling value R1 to RM; In buffer rb1 to rbN, store respectively sampling value RM+1 to RM+N.
In the time that the up-to-date sampling value providing of value switch 12 is provided, each buffer unit in offset buffer 14 to shift left (Shift), is vacated rightmost buffer unit (being buffer unit rbN) and comes the sampling value of this up-to-date input of buffer memory by the sampling value of buffer memory wherein whereby.And in offset buffer 14, more for example comprise overflow buffer 14c, in order in the time that offset buffer 14 receives i sampling value Ri, buffer memory i-(M+N) sampling value, is aforementioned overflow sampling value.
Operational instances taking the sampling value of up-to-date input as M+N+1 sampling value RM+N+1, in the time that offset buffer 14 not yet receives sampling value RM+N+1, buffer unit ra1 to raM is M sampling value R1 to RM of buffer memory respectively, and buffer unit rb1 to rbN is N sampling value RM+1 to RM+N of buffer memory respectively.Receive sampling value RM+N+1 and carry out after aforementioned shifting function at offset buffer 14, in offset buffer 14, the buffer unit rbN of the rightmost side is available with buffer memory M+N+1 stroke numeral value RM+N+1, and the M+N stroke numeral value RM+N of the former buffer memory of buffer unit rbN is stored in to shifting left in buffer rbN-1.Similar in appearance to aforesaid shifting function left, buffer unit ra1 to raM is the former sampling value R2 to RM+1 being stored in buffer unit ra2 to rb1 of buffer memory respectively; Buffer unit rb1 to rbN-2 is the former sampling value RM+2 to RM+N-1 being stored in buffer unit rb2 to rbN-1 of buffer memory respectively; And the former sampling value R1 that is cached in buffer unit ra1 is moved out of buffer unit ra1 and becomes overflow sampling value.And overflow buffer 14c is in order in the time that offset buffer 14 receives M+N+1 sampling value RM+N+1, buffer memory sampling value R1, is aforementioned overflow sampling value.
Arithmetic unit 16 is found out parameter b according to the sampling value of buffer memory in sliding window value device 14b, and it is in order to indicate the average energy size of i-(N-1) pen to i sampling value.Arithmetic unit 16 for example comprises buffer 16a, adder 16b, divider 16c and counter switch 16d.Buffer 16a adds total value Sb in order to store all buffer memory sampling value Ri-(N-1) in buffer unit rb1 to rbN to Ri.Adder 16b deducts the total value Sb that adds storing in buffer 16a i-N sampling value and adds i+1 sampling value, in the time of next record sampling value Ri+1 input offset buffer 14, upgrades the numerical value that adds total value Sb whereby.Divider 16c adds total value Sb divided by numerical value of N, to obtain indicating the parameter b of i-(N-1) pen to the average energy size of i sampling value.Counter switch 16d is coupled between divider 16c and comparator 20, and counter switch 16d is in response to control signal Sc conducting in the time that i is more than or equal to M+N, to provide parameter b to comparator 20.
Taking i equal M+N+1 and this next record sampling value as the operational instances of M+N+1 sampling value RM+N+1, when after RM+N+1 input offset buffer 14, in offset buffer 14, each rb1 to rbN carries out to the operation of shifting left, and makes buffer rb1 to rbN buffer memory sampling value RM+2 to RM+N+1 respectively.But what buffer 16a stored adds total value Sb is still corresponding with sampling value RM+1 to the RM+N total value Sb that adds.Accordingly, the total value Sb that adds storing in buffer 16a is deducted sampling value RM+1 by adder 16b, and add sampling value RM+N+1, at next record sampling value RM+N+1 input offset buffer 14, be updated to the add total value corresponding with sampling value RM+2 to RM+N+1 by adding total value Sb whereby.
Arithmetic unit 18 according to and sliding window value device 14a in the sampling value of buffer memory find out parameter a, it is in order to indicate the average energy size of sampling value Ri-(M+N-1) to Ri-N, and in order to the threshold value as parameter b.Arithmetic unit 18 for example comprises buffer 18a, adder 18b, divider 18c and multiplier 18d.Similar in appearance to arithmetic unit 16, the buffer 18a in arithmetic unit 18 is in order in buffer unit ra1 to raN, all sampling values add total value Sa.Adder 18b deducts the total value Sa that adds storing in buffer 18a i-(M+N) sampling value and adds i-N sampling value, in the time of next record sampling value input offset buffer 14, upgrades the numerical value that adds total value Sa whereby.Divider 18c adds total value Sa divided by numerical value M, to obtain operational parameter P.Multiplier 18d carries out multiplying to operational parameter P and weighting parameters K, obtains parameter a with computing.For instance, weighting parameters K is greater than 1 real number.
Taking i equal M+N+1 and this next record sampling value as the operational instances of M+N+1 sampling value RM+N+1, when after RM+N+1 input offset buffer 14, in the buffer 14 of position, each ra1 to raN carries out to the operation of shifting left, and makes buffer ra1 to raN buffer memory sampling value R2 to RM+1 respectively.But what buffer 18a stored adds total value Sa is still corresponding with sampling value R1 to the RM total value Sa that adds.Accordingly, the total value Sa that adds storing in buffer 18a is deducted sampling value R1 by adder 18b, and add sampling value RM+1, at next record sampling value RM+N+1 input offset buffer 14, be updated to the add total value corresponding with sampling value R2 to RM+1 by adding total value Sa whereby.
Comparator 20 judges whether parameter b is greater than in fact parameter a, to judge whether N sampling value Ri-(N-1) that the up-to-date sampling of digital signal R obtains is greater than the previous M of digital signal R sampling value Ri-(M+N-1) to Ri-N significantly to the mean value of R-i, and judge whereby whether the individual sampling time point of this i-(N-1) is the initial time point of signal of digital signal R.In the time that parameter b is greater than in fact parameter a, comparator 20 judges that the individual sampling time point of this i-(N-1) is the initial time point of digital signal R signal, and this i-(N-1) of instruction energy measuring signal ED of the initial time point of signal that individual sampling time point is digital signal R is provided accordingly.In the time that parameter b is less than or equal to parameter a, comparator 20 judges till the individual sampling time point of i-(N-1), the initial time point of signal of digital signal R not yet detected, and the energy measuring signal ED of instruction aforementioned information is provided accordingly.
Processor 22 is carried out energy detection method, to control the integrated operation of energy measuring circuit 1.For instance, the energy detection method that processor 22 is carried out can be as shown in the flow chart of Fig. 3 A to 3C.For instance, this control method comprises following step.First as step 200, in the time that i is less than M+N (the sampling value number that is input offset buffer 14 is less than numerical value M+N), processor 22 provides control signal Sc with disabled counter switch 16d.So, the parameter b that arithmetic unit 16 produces cannot provide to comparator 20, and comparator 20 judges that parameter b is less than parameter a accordingly, and the energy measuring signal ED of the initial time point of signal that instruction not yet detects digital signal R is provided.Processor 22 more carrys out conducting value switch 12 in response to the aforementioned energy measuring signal ED generation control signal Ec that the initial time point of this signal not yet detected, to provide digital signal R to correspond to the next next record sampling value that samples time point to offset buffer 14, in other words, be that numerical value i is increased progressively to 1 so that offset buffer 14 accordingly buffer memory i-(M+N-1) to i sampling value Ri-(M+N-1) to Ri.
Then as step 201, judge the satisfied M+N that is greater than of numerical value i; If not, the energy detection method repeated execution of steps 200 of the present embodiment, with incremental value i constantly.When numerical value i meets while being more than or equal to the condition of M+N, processor 22 provides control signal Sc with activation counter switch 16d.Accordingly, energy detection method is jumped out the cycling of repeated execution of steps 200, and the parameter b that arithmetic unit 16 produces can be provided to comparator 20, and comparator 20 can be carried out accordingly and judge whether parameter b is less than the operation of parameter a whereby.
For instance, energy detection method is being jumped out the rear execution step 202 of step 200, processor 22 is set weighting parameters K and is had initial value, and so in energy measuring circuit 1, each circuit can be carried out aforementioned operation according to the weighting parameters K with this initial value, to find out parameter a and b.For instance, this initial value is the greatest measure of weighting parameters K.Because weighting parameters K is positively correlated with the numerical value of parameter a (being the threshold value of parameter b), the maximum that it is it that the maximum that weighting parameters K is made as to it also represents the Threshold of parameter b.In other words, now energy measuring circuit 1 is with the strictest criterion, the initial time point of the signal of digital signal R to be detected, the energy value of the energy value that has i sampling value only much larger than i-(M+N-1) to i-1 sampling value, and parameter b is greater than in the situation with the parameter a of the highest weighting parameters K weighting, energy measuring circuit 1 begins to judge and corresponds to the initial time point of signal that the individual sampling time point of this i-(N-1) of i-(N-1) sampling value is digital signal R.
Then as step 204, judge via comparator 20 whether parameter b is greater than parameter a and energy measuring signal ED is provided, processor 22 can judge whether the individual sampling time point of this i-(N-1) is the initial time point of signal of digital signal R accordingly, and whether energy measuring circuit 1 completes energy measuring operation.In the time that processor 22 receives instruction and the energy measuring signal ED of the initial time point of signal of digital signal R not yet detected, represent that now the criterion of energy measuring circuit 1 is too harsh.Now this detection method execution step 206, processor 22 reduces the numerical value of weighting parameters K, to reduce the numerical values recited of parameter a (being the threshold value of parameter b).Whereby, processor 22 reduces energy measuring circuit 1 and detects the threshold condition of the initial time point of signal of digital signal R accordingly.In step 206, processor 22 more produces control signal Ec, for example, to drive value switch 12 for example, to provide next record sampling value (being i+1 sampling value Ri+1) at next one sampling time point (being i+1 sampling time point).Whereby, weighting parameters K after energy measuring circuit 1 can downgrade according to numerical value repeats aforementioned operation, to judge that accordingly next sampling time point is whether as the initial time point of signal of digital signal R, and whether energy measuring circuit 1 completes energy measuring operation accordingly.
When receiving this i of instruction, processor 22 samples time point while being the energy measuring signal ED of the initial time point of signal of digital signal R, represent that energy measuring circuit 1 completes aforementioned energy measuring operation, whether processor 22 performs step 208 accordingly, successful to judge the simultaneous operation of digital signal R.When simultaneous operation when failure of digital signal R, represent that in abovementioned steps 204, processor 22 judges that this i sampling time point is the false judgment event that is judged as (False Alarm) of the initial time point of signal of digital signal R, and detection method execution step 210, processor 22 increases the numerical value of weighting parameters K, to promote the numerical values recited of parameter a (being the threshold value of parameter b).Whereby, processor 22 improves energy measuring circuit 1 and detects the threshold condition of the initial time point of signal of digital signal R accordingly, to reduce the chance of aforementioned false judgment event.In step 210, processor 22 more produces control signal Ec, for example, to drive value switch 12 for example, to provide next record sampling value (being i+1 sampling value Ri+1) at next one sampling time point (being i+1 sampling time point).Whereby, weighting parameters K after energy measuring circuit 1 can increase according to numerical value repeats aforementioned operation, to judge that accordingly next sampling time point is whether as the initial time point of signal of digital signal R, and whether energy measuring circuit 1 completes energy measuring operation accordingly.
After step 208, when simultaneous operation when success of digital signal R, represent the initial time point of signal that the individual sampling time point of this i-(N-1) is digital signal R, and this detection method execution step 212, processor 22 calculates the signal noise ratio (Signal to Noise Ratio, SNR) of input signal Si.Then as step 214, processor 22 is tabled look-up (Lookup Table) with reference to one, sets weighting parameters K according to the signal noise ratio of input signal Si.For instance, this table look-up can be as shown in Figure 4.
With the example shown in Fig. 4, in the time that the SNR of input signal Si is higher, the signal quality that represents input signal Si is better, and processor 22 is selected accordingly the weighting parameters K that numerical value is higher in step 212, to select accordingly higher criterion to detect the initial time point of the signal of digital signal R; In the time that the SNR of input signal Si is lower, the signal quality that represents input signal Si is poor, and processor 22 is selected accordingly the weighting parameters K that numerical value is lower in step 212, to select accordingly lower criterion to detect the initial time point of the signal of digital signal R.In step 212, processor 22 more produces control signal Ec, for example, to drive value switch 12 for example, to provide next record sampling value (being i+1 sampling value Ri+1) at next one sampling time point (being i+1 sampling time point).Whereby, energy measuring circuit 1 can repeat aforementioned operation according to the weighting parameters K after numerical value adjustment, to judge that accordingly next sampling time point is whether as the initial time point of signal of digital signal R, and whether energy measuring circuit 1 completes energy measuring operation accordingly.
Then this detection method is carried out the step 216 similar to step 204, judges via comparator 20 whether parameter b is greater than parameter a and provides accordingly energy measuring signal ED, processor 22 can judge accordingly whether energy measuring circuit 1 completes energy measuring operation; If not, repeating step 212, to calculate the signal noise ratio of input signal Si.In the time that energy measuring circuit 1 completes energy measuring operation, perform step 218, processor 22 judges whether to want to proceed energy measuring operation; If so, repeating step 212, to calculate the signal noise ratio of input signal Si; If not, stop energy detection method.
The energy detection method of the present embodiment and energy measuring circuit, in order to according to the digital signal that corresponds to input signal, are found out the initial time point of signal of this input signal.Further, the energy detection method of the present embodiment and energy measuring circuit application: two sliding window value devices, with in the time receiving i sampling value of digital signal, respectively buffer memory i-(M+N-1) pen is to i-N sampling value and i-(N-1) pen to i sampling value; Two arithmetic units, find out respectively the first parameter and the second parameter, and it corresponds to respectively with the average energy value of M sampling value before after weighting parameters K weighting and corresponds to the average energy value of a rear N sampling value; Comparator, it is the threshold value as the second parameter with the first parameter, come comparison this first and this second parameter; Processor, in the time that the second parameter is greater than the first parameter in fact, calculate the SNR of input signal, and the SNR of reference-input signal sets the numerical value of weighting parameters K accordingly.Accordingly, compared to conventional energy detection method, the energy detection method of the present embodiment and energy measuring circuit have can be via adjusting weighting parameters K, comes that energy detection threshold is dynamically adjusted in adaptive ground, noise resisting ability accuracy better and energy measuring is higher.
Certainly; the present invention also can have other various embodiments; in the situation that not deviating from spirit of the present invention and essence thereof; those of ordinary skill in the art can make according to the present invention various corresponding changes and distortion, but these corresponding changes and distortion all should belong to the protection range of the claims in the present invention.
Claims (16)
1. an energy measuring circuit, is applied in a receiver, in order to the signal with reference to corresponding with an input signal, finds out the initial time point of a signal that this input signal is corresponding, it is characterized in that, this energy measuring circuit comprises:
One value switch, in order to be conducting in response to a control signal, so that an i sampling value of this signal to be provided in an i sampling time point, wherein i is greater than 1 natural number;
One offset buffer, in order to buffer memory one i-(M+N-1) pen, to this i sampling value, wherein M and N are greater than 1 natural number, and this offset buffer comprises:
One first sliding window value device, in order to this i-(M+N-1) of buffer memory pen to an i-N sampling value;
One second sliding window value device, in order to buffer memory one i-(N-1) pen to this i sampling value;
One first arithmetic device, in order to find out one first parameter according to a weighting parameters and this i-(M+N-1) pen to this i-N sampling value;
One second arithmetic device, in order to find out one second parameter according to this i-(N-1) pen to this i sampling value;
One comparator, in order to relatively this first and this second parameter, and in the time that this second parameter is greater than this first parameter, provide an energy measuring signal; And
One processor, there is an initial value in order to set this weighting parameters, this processor more judges whether to receive this energy measuring signal, and in the time receiving this energy measuring signal, judge that the individual sampling time point of an i-(N-1) that corresponds to i-(N-1) sampling value is the initial time point of this signal.
2. according to the described energy measuring circuit of claim 1, it is characterized in that, this processor more judges the whether success of simultaneous operation of this signal, in the time of the simultaneous operation success of this signal, this processor calculates a signal noise ratio of this input signal, and sets according to this this weighting parameters;
Wherein, this processor more provides this control signal in the time that this second parameter is not more than this first parameter, to drive this value switch that i+1 sampling value is provided.
3. according to the described energy measuring circuit of claim 1, it is characterized in that, this offset buffer more comprises: an overflow buffer, and in order to buffer memory one i-(M+N) sampling value.
4. according to the described energy measuring circuit of claim 1, it is characterized in that, this first arithmetic device comprises:
One buffer, adds total value in order to buffer memory one i-(M+N) pen to one first of i-(N+1) sampling value;
One adder, in order to this first is added to total value and deduct this i-(M+N) sampling value, and adds this i-N sampling value, adds total value to find out this i-(M+N-1) pen to one second of this i-N sampling value;
One divider, in order to this second is added to total value divided by numerical value M, to obtain operational parameter; And
One multiplier, in order to obtain this first parameter according to this operational parameter and this weighting parameters computing.
5. according to the described energy measuring circuit of claim 1, it is characterized in that, this second arithmetic device comprises:
One buffer, adds total value in order to one first of i-1 sampling value of this i-N pen to the of buffer memory;
One adder, in order to this first is added to total value and deduct this i-N sampling value, and adds this i sampling value, adds total value to find out this i-(N-1) pen to one second of this i sampling value; And
One divider, in order to this second is added to total value divided by numerical value of N, to obtain this second parameter.
6. according to the described energy measuring circuit of claim 5, it is characterized in that, this second arithmetic device more comprises: a counter switch, is coupled between this divider and this comparator, in order to conducting in the time that i is more than or equal to M+N, to provide this second parameter to this comparator.
7. according to the described energy measuring circuit of claim 1, it is characterized in that, when simultaneous operation when failure of this signal, this processor judges that this sampling time point is the false judgment event that is operating as of the initial time point of this signal, and this processor more increases the numerical value of this weighting parameters;
Wherein, this first arithmetic device is found out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of increasing after operation, this first parameter and this second parameter after this comparator relatively upgrades accordingly, and in the time that this second parameter is greater than this first parameter after renewal, provide the signal of the energy measuring after a renewal;
Wherein, this processor judges whether to receive the energy measuring signal after this renewal more constantly, and when energy measuring signal after receiving this renewal, judges the whether success of simultaneous operation of this signal.
8. according to the described energy measuring circuit of claim 7, it is characterized in that, when simultaneous operation when success of this signal, this processor calculates the signal noise ratio of this input signal, and sets according to this this weighting parameters.
9. according to the described energy measuring circuit of claim 1, it is characterized in that, in the time not receiving this energy measuring signal, this processor downgrades the numerical value of this weighting parameters;
Wherein, this first arithmetic device is found out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of downgrading after operation, this first parameter and this second parameter after this comparator relatively upgrades accordingly, and in the time that this second parameter is greater than this first parameter after renewal, provide the signal of the energy measuring after a renewal;
Wherein, this processor judges whether to receive the energy measuring signal after this renewal more constantly, and when energy measuring signal after receiving this renewal, judges the whether success of simultaneous operation of this signal.
10. according to the described energy measuring circuit of claim 9, it is characterized in that, when simultaneous operation when success of this signal, this processor calculates the signal noise ratio of this input signal, and sets according to this this weighting parameters.
11. 1 kinds of energy detection methods, are applied in a receiver, with the signal with reference to corresponding with an input signal, find out the initial time point of a signal that this input signal is corresponding, it is characterized in that, this energy detection method comprises:
In a sampling time point, this signal is sampled, to find out an i sampling value, wherein i is greater than 1 natural number;
Buffer memory one i-(M+N-1) pen is to an i-N sampling value, and buffer memory one i-(N-1) pen is to an i sampling value, and wherein M and N are greater than 1 natural number;
Set a weighting parameters and there is an initial value;
Find out one first parameter according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value, and find out one second parameter according to this i-(N-1) pen to this i sampling value;
Relatively this first and this second parameter, to judge whether this second parameter is greater than this first parameter;
In the time that this second parameter is greater than this first parameter, one energy measuring signal is provided, to judge that the individual sampling time point of an i-(N-1) that corresponds to i-(N-1) sampling value is as the initial time point of this signal, and judge that whether the simultaneous operation of this signal is successful; And
When simultaneous operation when success of this signal, calculate a signal noise ratio of this input signal, and set according to this this weighting parameters.
12. according to the described energy detection method of claim 11, it is characterized in that, more comprises:
When simultaneous operation when failure of this signal, judge that this sampling time point is the false judgment event that is operating as of the initial time point of this signal, and increase the numerical value of this weighting parameters;
Find out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of increasing after operation;
This first parameter and this second parameter after relatively upgrading, and in the time that this second parameter is greater than this first parameter after renewal, provide the signal of the energy measuring after a renewal;
Relatively this first and this second parameter, to judge whether this second parameter is greater than this first parameter;
In the time that this second parameter is greater than this first parameter, energy measuring signal after a renewal is provided, to indicate this sampling time point as the initial time point of this signal, and judge the whether success of simultaneous operation of this signal; And
When simultaneous operation when success of this signal, calculate this signal noise ratio of this input signal, and set according to this this weighting parameters.
13. according to the described energy detection method of claim 11, it is characterized in that, more comprises:
In the time that this second parameter is not more than this first parameter, downgrade the numerical value of this weighting parameters;
Find out this first parameter after renewal according to this weighting parameters and this i-(M+N-1) pen to this i-N sampling value of downgrading after operation;
This first parameter and this second parameter after relatively upgrading, and in the time that this second parameter is greater than this first parameter after renewal, provide energy measuring signal after a renewal to indicate this sampling time point as the initial time point of this signal, and judge the whether success of simultaneous operation of this signal; And
When simultaneous operation when success of this signal, calculate this signal noise ratio of this input signal, and set according to this this weighting parameters.
14. according to the described energy detection method of claim 11, it is characterized in that, more comprises:
Buffer memory one i-(M+N) sampling value.
15. according to the described energy detection method of claim 14, it is characterized in that, comprises according to this weighting parameters and this i-(M+N-1) the step of finding out this first parameter to this i-N sampling value:
This i-(M+N) pen to one first of i-(N+1) sampling value of buffer memory adds total value;
This first is added to total value and deduct this i-(M+N) sampling value, and add this i-N sampling value, add total value to find out this i-(M+N-1) pen to one second of this i-N sampling value; And
This second is added to total value divided by numerical value M, to obtain this first parameter.
16. according to the described energy detection method of claim 11, it is characterized in that, the step of finding out this second parameter to this i sampling value according to this i-(N-1) pen comprises:
One first of i-1 sampling value of this i-N pen to the of buffer memory adds total value;
This first is added to total value and deduct this i-N sampling value, and add this i sampling value, add total value to find out this i-(N-1) pen to one second of this i sampling value; And
This second is added to total value divided by numerical value of N, to obtain this second parameter.
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