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TOMMUNODUNUT U UITA DAN US010079703B1

( 12 ) United States Patent Su

( 10 ) Patent No . : US 10 , 079 , 703 B1 ( 45 ) Date of Patent : Sep . 18 , 2018

OTHER PUBLICATIONS ( 54 ) USE OF AN ECHO SIGNAL IN SYNCHRONIZATION OF MULTIPLE SIGNAL COLLECTIONS FROM MULTIPLE SENSORS

( 71 ) Applicant : The United States of America , as represented by the Secretary of the Army , Washington , DC ( US )

( 72 ) Inventor : Wei Su , Bel Air , MD ( US )

Su et al . , “ Framework of Network Centric Signal Sensing for Automatic Modulation Classification , ” 2010 IEEE International Conference on Networking , Sensing and Control , Chicago , IL . Apr . 2010 . Xu , et al . , “ Distributed Automatic Modulation Classification with Multiple Sensors . ” IEEE Sensors Journal , vol . 10 , Issue : 11 , Nov . 2010 , pp . 1779 - 1785 . Xu , et al . , “ Asynchronous and High Accuracy Digital Modulated Signal Detection by Sensor Networks , ” MILCOM 2011 , Baltimore , MD , Nov . 2011 . Zhang , et al . , “ Optimal Decision Fusion based Automatic Modula tion Classification by using Wireless Sensor Networks in Multipath Fading Channel , ” IEEE GlobeCom 2011 , Huston , TX , Dec . 2011 .

( Continued )

( 73 ) Assignee : The United States of America , as represented by the Secretary of the Army , Washington , DC ( US )

( * ) Notice : Subject to any disclaimer , the term of this patent is extended or adjusted under 35 U . S . C . 154 ( b ) by 1482 days .

( 21 ) Appl . No . : 13 / 782 , 069 Primary Examiner — Willie J Daniel , Jr . ( 74 ) Attorney , Agent , or Firm — Ronald Krosky ; Azza Jayaprakash

( 22 ) Filed : Mar . 1 , 2013 ( 51 ) Int . CI .

H04L 27 / 00 ( 2006 . 01 ) H04L 1 / 00 ( 2006 . 01 ) U . S . CI . CPC . . . . . . . . H04L 27 / 0012 ( 2013 . 01 ) ; H04L 1 / 0009

( 2013 . 01 ) Field of Classification Search None See application file for complete search history .

( 58 )

( 57 ) ABSTRACT Various embodiments associated with use of an echo signal are described . A plurality of sensors can be deployed to obtain editions of a signal of interest . The signal of interest may be so far away from the sensors that the editions collected are too noisy to be analyzed . A processing center can send an echo signal to the sensors and the sensors can respond to the processing center with a signal edition of the signal of interest and the echo signal . Since the processing center knows information about the echo signal , offsets among the sensors can be calculated based on the returned echo signals . These offsets can then be used to align the signal editions . At the processing center , the aligned signal editions can be combined into a combined signal and a demodulation scheme for the combined signal can be deter mined and then used for demodulation of the signal .

( 56 ) References Cited U . S . PATENT DOCUMENTS

8 , 085 , 882 B1 12 / 2011 Su 8 , 326 , 240 B1 * 12 / 2012 Kadambe . . . . . . . . . . . H04B 1 / 70735

455 / 114 . 2 8 , 917 , 802 B1 * 12 / 2014 Su . . . . . . . . . . . . . . . . . . . . HO4L 27 / 0012

375 / 343 . . . H042495 / 14 . 2 20 Claims , 14 Drawing Sheets

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Sensor Spectrum Sensing and Signal

Classification LO 10

US 10 , 079 , 703 B1 Page 2

( 56 ) References Cited

OTHER PUBLICATIONS Zhang , et al . , “ Multi - sensor Signal Fusion based Modulation Clas sification by using Wireless Sensor Networks in AWGN Channel , ” IEEE International Conference on Communications , Kyoto , Japan , Jun . 2011 . Su , et al . , “ Dual - use of Modulation Recognition Techniques for Digital Communication Signals , ” in Proc . IEEE LISAT , Long Island , NY , May 2006 , pp . 1 - 6 .

* cited by examiner

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EMISSION COMPONENT COLLECTION COMPONENT COMPUTER READABLE MEDIUM FIG . 2


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COLLECTION COMPONENT

COMPENSATION COMPONENT

500

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c510

COMPUTER READABLE MEDIUM

CALCULATION COMPONENT 410

Sheet 5 of 14

r

520

SPLITTER COMPONENT

DETERMINATION COMPONENT FIG . 5

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DEMODULATION COMPONENT

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SPLITTER COMPONENT r

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Sep . 18 , 2018


OFFSET COMPONENT

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COMPENSATION COMPONENT 710

Sheet 7 of 14

FUSION COMPONENT FIG . 7

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U . S . Patent

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EMISSION COMPONENT I

OFFSET COMPONENT OFFSET COMPONENT 220

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Sep . 18 , 2018

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FUSION COMPONENT 410

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SPLITTER COMPONENT

COMPUTATION COMPONENT

Sheet 8 of 14

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THRESHOLD COMPONENT FIG . 8

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COMPARISON COMPONENT

Sep . 18 , 2018

r

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RE - SAMPLE COMPONENT 410

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SPLITTER COMPONENT

Sheet 9 of 14

FUSION COMPONENT 940

DETERMINATION COMPONENT FIG . 9

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OFFSET COMPONENT COMPENSATION COMPONENT PROCESSOR FIG . 10


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OFFSET COMPONENT COMPENSATION COMPONENT PROCESSOR MATCH COMPONENT FIND COMPONENT FIG . 11

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Sheet 12 of 14

CONSTELLATION COMPONENT FIG . 12

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COLLECT EDITIONS

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CALCULATE OFFSET

Sheet 13 of 14

1350

MODIFY EDITION

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COMBINE EDITIONS FIG . 13

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U . S . Patent

1310

1400

CAUSE EMISSION

1360

COMBINE EDITIONS

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COLLECT EDITIONS

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Sep . 18 , 2018

DETERMINE CONSTELLATION 1330

SEPARATE EDITIONS FROM ECHO SIGNAL

1420

MATCH CONSTELLATION 1340

Sheet 14 of 14

CALCULATE OFFSET

1430

IDENTIFY AND DESIGNATE SCHEME

1350

MODIFY EDITION

-

1440

CAUSE DEMODULATION FIG . 14

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USE OF AN ECHO SIGNAL IN comprises collecting a first edition of an echo signal with a SYNCHRONIZATION OF MULTIPLE first edition of a signal of interest from the first sensor , where

SIGNAL COLLECTIONS FROM MULTIPLE a network of the signal of interest is unknown . The method SENSORS additionally comprises collecting a second edition of the

5 echo signal with a second edition of the signal of interest GOVERNMENT INTEREST from the second sensor , where a network of the signal of

interest is unknown , where the first edition of the signal of The innovation described herein may be manufactured , interest and the second edition of the signal of interest are

used , imported , sold , and licensed by or for the Government not identical . The method also comprises separating the first of the United States of America without the payment of any 10 edition of the echo signal from the first edition of the signal royalty thereon or therefor . of interest . In addition , the method comprises separating the

second edition of the echo signal from the second edition of BACKGROUND the signal of interest . Further , the method comprises calcu

In a combat environment , different forces can broadcast 15 lating an offset of the first edition of the echo signal against different signals . In a singular environment , enemy combat the second edition of the echo signal . The method addition ants can each broadcast different signals . It may be possible ally comprises modifying the second edition of the signal of for one combatant to intercept the signal of another com interest through use of the offset to produce a modified batant . The intercepting combatant may not know the modu second edition of the signal of interest . The method also lation scheme of an intercepted signal . Without the modu - 20 comprises combining the first edition of the signal of interest lation scheme , it may be difficult to put the intercepted signal and the modified second edition of the signal of interest to to use . produce a combined signal of the signal of interest .

SUMMARY BRIEF DESCRIPTION OF THE DRAWINGS 25

A system comprising an emission component , a collection Incorporated herein are drawings that constitute a part of component , and a non - transitory computer - readable medium the specification and illustrate embodiments of the detailed is described . The emission component is configured to cause description . The detailed description will now be described an emission of an echo signal to a first sensor and a second further with reference to the accompanying drawings as sensor , where the first sensor and the second sensor are 30 follows : different sensors . The collection component is configured to FIG . 1 illustrates one embodiment of a system comprising collect a first edition of the echo signal with a first edition of sensors and a fusion center ; a signal of interest from the first sensor and configured to FIG . 2 illustrates one embodiment of a system comprising collect a second edition of the echo signal with a second an emission component , a collection component , and a edition of the signal of interest from the second sensor . The 35 computer - readable medium ; first edition of the echo signal , the first edition of the signal FIG . 3 illustrates one embodiment of a system comprising of interest , the second edition of the echo signal , and the the emission component , the collection component , the second edition of the signal of interest are used to select a computer - readable medium , and an evaluation component ; demodulation scheme for the signal of interest . The non - FIG . 4 illustrates one embodiment of a system comprising transitory computer - readable medium is configured to retain 40 the emission component , the collection component , the at least one instruction associated with the emission com - computer - readable medium , a splitter component , an offset ponent or the collection component component , and a compensation component ;

In addition , a system is described comprising an offset FIG . 5 illustrates one embodiment of a system comprising component that performs a calculation of an echo signal the emission component , the collection component , the offset , where the echo signal offset is calculated through 45 computer - readable medium , the splitter component , the off comparison of a first edition of the echo signal against a set component , the compensation component , a calculation second edition of the echo signal , where the first edition of component , and a determination component ; the echo signal is collected with a first edition of a signal of FIG . 6 illustrates one embodiment of a system comprising interest from a first sensor , where the second edition of the the emission component , the collection component , the echo signal is collected with a second edition of the signal 50 computer - readable medium , the splitter component , a of interest from a second sensor , where a network of the demodulation component , the offset component , the com signal of interest is unknown , where the first edition of the pensation component , the calculation component , the deter signal of interest and the second edition of the signal of mination component , and an output component ; interest are not identical , and where the first sensor and FIG . 7 illustrates one embodiment of a system comprising second sensor are different sensors . The system also com - 55 the emission component , the collection component , the prises a compensation component that performs a compen - computer - readable medium , the splitter component , the off sation for the second edition of the signal of interest through set component , the compensation component , and a fusion use of the echo signal offset . The system further comprises component ; a processor that executes at least one instruction associated FIG . 8 illustrates one embodiment of a system comprising with the offset component or the compensation component . 60 the emission component , the collection component , the Moreover , a non - transitory computer - readable medium is computer - readable medium , the splitter component , the off

also described that is configured to store computer - execut set component , the compensation component , the fusion able instructions that when executed by a processor cause component , a computation component , and a threshold the processor to perform a method . The method comprises component ; causing an emission of an echo signal to a first sensor and 65 FIG . 9 illustrates one embodiment of a system comprising of the echo signal to a second sensor , where the first sensor the emission component , the collection component , the and the second sensor are different sensors . The method also computer - readable medium , the splitter component , a

US 10 , 079 , 703 B1

sa sample component , a comparison component , a re - sample RPO by using an echo signal ( ES ) transmitted by the fusion component , the fusion component , and a determination center and then fed back by the distributed sensors . component ; FIG . 1 illustrates one embodiment of sensors ( with LOs )

FIG . 10 illustrates one embodiment of a system compris and a fusion center ( comprising a filter module , SOI Snap ing the offset component , the compensation component , and 5 shot module , ES Snapshot module , a frequency and phase a processor ; compensation module , a frequency and phase estimators

FIG . 11 illustrates one embodiment of a system compris module , time , frequency , and phase fine tuning module , ing the offset component , the compensation component , the signal fusion module , and spectrum sensing and signal processor , a match component , and a find component ; classification module ) , shown in combination as a system

FIG . 12 illustrates one embodiment of a system compris - 10 100 . When the SOI is transmitted with low - power or in a ing the offset component , the compensation component , the remote location ( e . g . , the SOI is transmitted from a ship or processor , the match component , the find component , a in a space vehicle and the sensors are along the shore or in moment component , and a constellation component ; an isolated geographical area or when the sensors are in

FIG . 13 illustrates one embodiment of a method compris unfavorable or noisy receiving locations ) , the SOI copies ing various actions ; and collected at distributed sensors may be too weak to analyze .

FIG . 14 illustrates one embodiment of a method compris In a dumb sensor and smart fusion center scenario , the ing other actions in addition to the various actions . sensors are asynchronous and the fusion center combines the

signal copies after a post - synchronization process . When the DETAILED DESCRIPTION asynchronous signal copies are very weak , the post - synchro

20 nization becomes very difficult and unreliable . Therefore , an Asynchronous low - cost sensors can be employed in dis - ES is transmitted by the fusion center to the sensors together

tributed locations for sensing and classifying a very weak with the RS for collecting SOI . The ES can be transmitted signal . This weak signal may not be identifiable through use in the same frequency as the SOI , or RS , or in different of a single sensor alone ( e . g . , due to the weak nature of the frequencies . The RS itself can serve as the ES in that one signal ) , but can be detected and classified by fusing multiple 25 signal is transmitted by the fusion center . The sensors may weak signal copies together , where the signal copies ( e . g . , or may not be configured to make local decisions and store editions ) are collected by a sensor network . These signal the short snapshots , r ; ( t ) , i = 1 , 2 , . . . , L , as time - stamped data copies , which are asynchronous due to the sensors being packets and forward them to the fusion center for process asynchronous , can have relative offsets in both frequency ing . The packets can be transmitted to the fusion center using and phase due to the diversities and drifts in the distributed 30 a communication method . Without loss of generality , R , is local oscillators . A synchronization method can be employed assumed to be the reference sensor , R2 , R2 , . . . , and R , are to estimate the relative offsets by transmitting an echo signal compared to R for calculating offsets ( e . g , the offset of R2 to the asynchronous sensors . The returning echo signal is based on a difference of R , from R , ) . A signal packet copies which have been contaminated by local oscillators received at the fusion center can include an SOI copy and an can be used for estimating the relative offsets . The weak 35 ES copy described by signal is compensated by using the estimated offsets of the r ; ( t ) = AQ ; < / ( Awit + Aßi [ s ( t + AT ; ) + s? ( t + ATE ; ) ] + n ; ( 1 ) echo signal and coherently combined to achieve a higher processing gain for reliable signal exploitation . where Aw ; and AB ; are RFO and RPO induced by LOs , At ;

A central decision ( e . g . , at a fusion center ) based distrib - is the relative time offset ( RTO ) , ATE , is the relative time uted signal sensing method can employ simple , inexpensive , 40 offset associated with ES , and Aa ; is the relative magnitude low - maintenance , and heterogeneous sensors so sensing offset ( RMO ) which does not need to be known . When i = 1 , devices can be deployed to cover a wide spread geographical Aw1 = AB 1 = AT1 = ATE , 1 = 0 . Relative offsets are referring to area seamlessly and multiple narrow - band receivers can be ri ( t ) = s ( t ) + se ( t ) + ni ( t ) collaborated to handle a wide frequency band effectively . The distributed sensors can be clustered and orchestrated by 45 Where s ( t ) = 20 $ o { t + Tole 45 where s ( t ) = a . s . ( t + T . ) e ( @ it + + ßo ) and se ( t ) are the frequency the fusion center which has sufficient processing power to down - converted copies of the SOI and ES , respectively , process the signal copies . The fusion center can periodically observed at Rj , so ( t ) is a sequence of pulse shaped infor send a requesting signal ( RS ) to L distributed sensors , Ri , mation symbols , do , Wo , Bo , To are gain , frequency , phase , R2 , . . . , and R , to acquire a signal of interest ( SOI ) that is and time otsets between the sol and Ri , respectively , and weak . Upon the reception of the request , the distributed 50 n ; ~ N 0 , 0 , ) is i . i . d . circularly symmetric complex additive sensors take short time duration snapshots of the SOI . The white Gaussian noise ( AWGN ) . When periodical short snap distributed sensors may provide very limited signal process - shots of SOI are used , there may be ample time between two ing capabilities such as radio frequency reception and trans snapshots for signal processing and analysis . When AWGN mission , frequency tuning and down - conversion , filtering channels are used ( as well as possibly other channels ) , and digitization . Thus , sensors may be asynchronous and 55 aspects disclosed herein can be conducted in real - time . non - cooperative to one another and may be used for com - The fusion center can comprise an antenna , a Relative municating with , or relaying distributed snapshots to , the Sampling - frequency Offset ( RSO ) Estimator and Resam fusion center . If the frequency down - conversion local oscil - pler , an ES and SOI Splitter , registers for ES copies and SOI lators ( LOs ) are all different due to heterogeneous and copies , and estimators and compensators for RFO and RPO . asynchronous characteristics , the fusion center can be con - 60 The SOI and ES copies received at the fusion center are sent figured to estimate and compensate the relative frequency to the FSO estimator and resampler to correct the sampling offset ( RFO ) and the relative phase offset ( RPO ) induced by offset such that the samples from different signal copies will different LOs at the distributed locations before combining be lined up in time for further processing . The symbol rate the signal copies coherently . However , if the SOI is very of the SOI can be used as a reference for estimating RSO and weak ( e . g . , below 0 dB Signal - to - Noise Ratio ( SNR ) ) , then 65 the signal copies with RSOs can be interpreted and re the offset estimation may become unreliable . To compensate sampled after RSO estimation . The splitter separates a for this , a method can be employed to estimate RFO and received signal copy , ri , to an ES copy , rej ( t ) = Aage ( 46 ; t + AP : )

US 10 , 079 , 703 B1 un

of

SE ( t + ATE . ; ) , and an SOI copy , rsi ( t ) = Aage ( A0 ; t + Api ) s ( t + At ; ) , center ) can be memories or storage devices ( e . g . , a non for i = 1 , 2 , . . . , L . The ES copies are stored in ES - copy transitory computer - readable medium ) . Estimators , compen registers and SOI copies are stored in SOI - copy registers for sators , and a combiner can be signal processors ( such as a signal processing . processor ) . When the channel is not AWGN , the channel

The ES copies from L sensors are sent to the Relative 5 phases can be added to the signal snapshots observed in the Frequency and Phase Estimator for estimating the RFO and distributed locations and the additional RPO estimation can RTO induced by LOs . The ES can be designed to be be be applied or an adaptive filter will be used to compensate relatively short and strong , be an easily separated and the channel phase . synchronized signal which can be as simple as a tone , be a Aspects disclosed herein can be used for detecting remote repeated known code , etc . The estimates of RFO and RPO 10 weak signals from outer space , receiving low power trans can be obtained by taking the fast Fourier transform ( FFT ) mission signals , demodulate cell phone signal transmitted at

a location far away from towers , military or police surveil

q ( t ) = re , 1 * ( t ) rExlt - ATED ) lance of hostile transmission , spectrum survey of weak signals , and other applications .

where the RFO estimate Aw ; can found by searching a 15 The following includes definitions of selected terms maximum FFT magnitude in the frequency domain within a employed herein . The definitions include various examples . searching window , the RPO estimate AB , is the phase of FFT The examples are not intended to be limiting . at A0 ; , and Ate . i is an estimate of AE . i found by maximizing ) “ One embodiment ” , “ an embodiment ” , " one example ” ,

x [ ates ) = €1 " , 1 * ( + ) re , 1 ( ) re . " ( t - Aig . ) re : ( t - ATE ; ) dt ( 4 ) " an example ” , and so on , indicate that the embodiment ( s ) or 20 example ( s ) can include a particular feature , structure , char Assuming the RFO and RPO of LOs are not changed in acteristic , property , or element , but that not every embodi

the short observation time period , the estimates Aw ; and AB , ment or example necessarily includes that particular feature , can be used to compensate the RFO and RPO of SOI copies structure , characteristic , property or element . Furthermore , in the Relative Frequency and Phase Compensator as shown repeated use of the phrase " in one embodiment ” may or may below 25 not refer to the same embodiment .

" Computer - readable medium " , as used herein , refers to a medium that stores signals , instructions and / or data .

ni ( t ) = e - j ( AW + ABi ) rs , j ( t ) = Aq ; ejlAw ; - A? ) l + ABI - ABi s ( t + At ; ) + n ; ( t ) Examples of a computer - readable medium include , but are ~ Aa ; s ( t + AT ; ) + n ; ( t ) not limited to , non - volatile media and volatile media . Non

30 volatile media may include , for example , optical disks , magnetic disks , and so on . Volatile media may include , for

Under the scenario in which the SOI is far away for the example , semiconductor memories , dynamic memory , and sensors , the RTOs of SOI copies can be relatively small and so on . Common forms of a computer - readable medium may have little impact to the coherent combining of the SOI include , but are not limited to , a floppy disk , a flexible disk , copies . In the case where the RTO should be compensated , 35 a hard disk , a magnetic tape , other magnetic medium , other RTO can be estimated by searching the best t ; using a optical medium , a Random Access Memory ( RAM ) , a Relative Time Estimator and Compensator such that Read - Only Memory ( ROM ) , a memory chip or card , a

memory stick , and other media from which a computer , a processor or other electronic device can read . In one

( 6 ) 40 embodiment , the computer - readable medium is a non - tran sitory computer - readable medium .

" Component ” , as used herein , includes but is not limited to hardware , firmware , software stored on a computer

is a maximum within the searching window To . The L copies readable medium or in execution on a machine , and / or of SOI collected in the distributed locations are combined 45 combinations of each to perform a function ( s ) or an coherently at the SOI Copies Combiner as shown below : action ( s ) , and / or to cause a function or action from another

component , method , and / or system . Component may include a software controlled microprocessor , a discrete

e - jAw ; ( ti – Af ; ) + ABirsi ( t - AÎ ; ) + n ' ( 1 ) component , an analog circuit , a digital circuit , a pro 50 grammed logic device , a memory device containing instruc

tions , and so on . Where multiple components are described , it may be possible to incorporate the multiple components

to form a more accurate estimation of the SOI for exploi - into one physical component or conversely , where a single tation . Where nº ( t ) is the combined noise diminishing with component is described , it may be possible to distribute that a large L . Selection can occur on what signal copies are 55 single logical component between multiple components . combined . For example , one can choose to combine copies “ Software ” , as used herein , includes but is not limited to , with a higher SNRs or less channel distortion . In another one or more executable instructions stored on a computer example , one can stop combining when the SNR of the readable medium that cause a computer , processor , or other combined signal exceeds a threshold . The estimation of the electronic device to perform functions , actions and / or offsets can be calculated use parallel processing . The com - 60 behave in a desired manner . The instructions may be embod bined signal can be used for the signal sensing , classifica - ied in various forms including routines , algorithms , mod tion , and localization . ules , methods , threads , and / or programs including separate

The fusion center can be designed to have the sufficient applications or code from dynamically linked libraries . computational power and bandwidth to handle and process A plurality of sensors can be deployed in an environment the signal copies provided by sensors in a short amount of 65 to obtain editions a signal of interest . However , the sensors time . ES and SOI registers ( ES Copy 1 to ES Copy L and may be so far away from the signal of interest that the SOI Copy 1 to SOI Copy L that can be part of the fusion editions are difficult to use . Therefore , an echo signal can be

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sent to the plurality of sensors and the sensors can respond signal of interest is of sufficient strength as well as config with the signal edition and the echo signal . Since the ured to perform a second evaluation of the second edition of processing center knows information about the echo signal , the signal of interest to determine if the second edition of the an offset can be calculated among returned echo signals . signal of interest is of sufficient strength . This offset can then be used to align the signal editions . Once 5 In one embodiment , editions of the signal of interest can aligned , the signal editions can be combined into a combined be collected by the collection component 220 without the signal that represents the signal of interest . A demodulation echo signal . These editions can be evaluated by the evalu scheme for the combined signal can be determined and the ation component 310 and a determination can be made that signal can be demodulated according to the demodulation the editions are too weak to process . The evaluation com scheme . ponent 310 can then cause the emission component 210 to FIG . 2 illustrates one embodiment of a system 200 send the echo signal to the sensors requesting that the signal comprising an emission component 210 , a collection com of interest be returned with an edition of the echo signal . ponent 220 , and a computer - readable medium 230 . The When the sensors comply , the echo signal can be used to emission component 210 is configured to cause an emission of an echo signal to a first sensor and a second sensor , where 15 better understand network diversity and perform processing the first sensor and the second sensor are different sensors . on the signal of interest editions . If the evaluation compo The collection component 220 is configured to collect a first nent 310 makes a determination that the editions are strong edition of the echo signal with a first edition of a signal of enough to process , then processing can occur without use of interest ( e . g . , the echo signal edition and signal of interest the echo signal . edition integrated together ) from the first sensor . The col - 20 FIG . 4 illustrates one embodiment of a system 400 lection component 220 is also configured to collect a second comprising the emission component 210 , the collection edition of the echo signal with a second edition of the signal component 220 , the computer - readable medium 230 , a split of interest from the second sensor . The first edition of the ter component 410 , an offset component 420 , and a com echo signal , the first edition of the signal of interest , the pensation component 430 . The splitter component 410 is second edition of the echo signal , and the second edition of 25 configured to separate the first edition of the echo signal the signal of interest are used to select a demodulation from the first edition of the signal of interest and configured scheme for the signal of interest . The computer - readable to separate the second edition of the echo signal from the medium 230 ( e . g . , non - transitory computer - readable second edition of the signal of interest . The offset compo medium ) is configured to retain at least one instruction nent 420 is configured to perform a calculation of an echo associated with the emission component or the collection 30 signal offset , where the echo signal offset is calculated component . through use of the first edition of the echo signal and the

In one embodiment , the first sensor is part of a first second edition of the echo signal . The compensation com electronic device with a primary purpose other than func - ponent 430 is configured to perform a compensation for an tioning as a sensor of the first edition of the signal of interest offset of the first edition of the signal of interest against the ( e . g . , a walkie - talkie radio ) and the second sensor is part of 35 second edition of signal of interest through use of the echo a second electronic device with a primary purpose other than signal offset . functioning as a sensor of the second edition of the signal of The collection component 220 can collect from the indi interest ( e . g . , another walkie - talkie radio , a different model vidual sensors a combined communication that includes an or brand of walkie - talkie radio , a tunable software - defined edition of the echo signal ( e . g . , an edition influenced by radio , etc . ) . The first electronic device and the second device 40 factors of the sensor , such as a frequency and phase offsets are different personal electronic devices . related to the sensor ) and an edition of the signal of interest

Thus , sensors can be part of already existent equipment . ( e . g . , with the same influence as that of the echo signal ) . The For example , various electronic devices can be carried by splitter component 410 can separate the echo signal editions soldiers in the battlefield . These electronic devices can be from the signal of interest editions . The offset component employed as sensors ( e . g . , when they are not being used for 45 420 can then calculate an offset between the first edition of their primary purpose ) . The devices can send signal editions the echo signal and the second edition of the echo signal . to a command center far away from the battlefield and the While a network of the signal of interest may not be known editions can be processed . and thus information may not be known about signal of

In one embodiment , the emission component 210 is interest . However , since the echo signal can be considered configured to cause emission of the echo signal with a signal 50 known to the network , then information is known about the of interest request signal ( e . g . , a separate signal of interest echo signal . For example , even if the signal edition is weak , request signal or the echo signal functions as the signal of the original echo signal is known so greater information can interest request signal ) to the first sensor and the second be ascertained . An offset for the echo signal can be calcu sensor . The first sensor sends the first edition of the echo lated , such as a difference between the first edition of the signal with the first edition of a signal of interest that is 55 echo signal and the second edition of the echo signal . Since collected by the collection component 220 in response to the a difference between the first edition of the echo signal and signal of interest request signal . In addition , the second the second edition of the echo signal should be the same as sensor sends the second edition of the echo signal with the a difference between the first edition of the signal of interest second edition of a signal of interest that is collected by the and the second edition of the signal of interest , the offset can collection component 220 in response to the signal of 60 be applied to the editions of the signal of interest . Therefore , interest request signal . the compensation component can modify one of the editions

FIG . 3 illustrates one embodiment of a system 300 of the signal of interest to align with another of the editions comprising the emission component 210 , the collection of the signal of interest . With the editions of the signal of component 220 , the computer - readable medium 230 , and an interest aligned , processing and combination can occur . evaluation component 310 . The evaluation component 310 65 In one embodiment , the calculation of the echo signal is configured to perform a first evaluation of the first edition offset comprises calculation of a relative frequency offset of the signal of interest to determine if the first edition of the and calculation of a relative phase offset . This can be in

US 10 , 079 , 703 B1 10

addition to some other offset calculation . In one embodi - third edition of the signal of interest . The third edition of the ment , the calculation comprises a fast Fourier transform . signal edition is added to the combined signal to increase the

FIG . 5 illustrates one embodiment of a system 500 fusing gain . comprising the emission component 210 , the collection While aspects disclosed herein address two sensors with component 220 , the computer - readable medium 230 , the 5 two signal editions ( e . g . , echo and signal of interest ) , it is to splitter component 410 , the offset component 420 , the be appreciated by one of ordinary skill in the art that more compensation component 430 , a calculation component 510 , than two sensors and more than two signal editions may be and a determination component 520 . The calculation com employed . In one example , five editions can be collected ponent 510 is configured to perform a mathematical opera from five different sensors . In one embodiment , the fusion tion ( e . g . , taking a moment of the editions of the signal of f 10 component 710 can fuse the five signals together . In one

embodiment , the fusion component can fuse two of the five interest , taking a cumulant of the editions of the signal of signal versions together into a combined signal . A third interest , etc . ) upon the first edition of the signal of interest edition can be added to the combined signal . This can after compensation and upon the second edition of the signal continue until there are no more signal editions that can be of interest after compensation to produce a mathematical 15 combined into the combined signal . result . Performance of the mathematical operation elimi FIG . 9 illustrates one embodiment of a system 900 nates uncorrelated noise of the first edition of the signal of comprising the emission component 210 , the collection interest and the second edition of the signal of interest . The component 220 , the computer - readable medium 230 , the determination component 520 is configured to make a splitter component 410 , a sample component 910 , a com determination on a modulation scheme for the signal of 20 parison component 920 , a re - sample component 930 , the interest based , at least in part , on the mathematical result , fusion component 710 , and a determination component 940 . where the modulation scheme is employed to demodulate The splitter component 410 is configured to separate the first the signal of interest . edition of the echo signal from the first edition of the signal

In one embodiment , the editions of the signal of interest of interest and is configured to separate the second edition of may include noise . Since noise is random , exact noise in one 25 the echo signal from the second edition of the signal of edition should not be present in another edition . A math - interest . The sample component 910 is configured to deter ematical operation can be performed upon the editions ( e . g . , mine a sample status of the second edition of the signal of editions before combination ) that eliminate the uncorrelated interest after the second edition of the signal of interest is noise , which can be done since the noise is random . The separated from the second edition of the echo signal . The editions of the signal of interest can then be combined and / or 30 comparison component 920 is configured to make a first be subjected to processing . threshold determination if the sample status of the second

FIG . 6 illustrates one embodiment of a system 600 edition of the signal of interest is at the acceptable level . The comprising the emission component 210 , the collection re - sample component 930 is configured to re - sample the component 220 , the computer - readable medium 230 , the second edition of the signal of interest to a re - sampled splitter component 410 , a demodulation component 610 , the 35 second edition of the signal of interest if the second thresh offset component 420 , the compensation component 430 , the old determination is that the sample status of the second calculation component 510 , the determination component edition of the signal of interest is not at the acceptable level . 520 , and an output component 620 . The demodulation The re - sampled second edition of the signal of interest is component 610 is configured to demodulate the signal of lined up in time with the first edition of the signal of interest . interest through employment of the modulation scheme . The 40 The fusion component 710 is configured to produce a output component 620 is configured to cause the signal of combined signal through combination of one of : the first interest to be outputted ( e . g . , transfer to a location , made edition of the signal of interest with the second edition of the available , etc . ) after being demodulated . signal of interest or the first edition of the signal of interest

FIG . 7 illustrates one embodiment of a system 700 with the re - sampled second edition of the signal of interest . comprising the emission component 210 , the collection 45 The determination component 940 is configured to make a component 220 , the computer - readable medium 230 , the determination on a modulation scheme for the signal of splitter component 410 , the offset component 420 , the interest based , at least in part , on the combined signal . compensation component 430 , and a fusion component 710 . FIG . 10 illustrates one embodiment of a system 1000 The fusion component 710 is configured to produce a comprising the offset component 420 , the compensation combined signal through combination of the first edition of 50 component 430 , and a processor 1010 . The offset component the signal of interest with the second edition of the signal of 420 performs a calculation of an echo signal offset , where interest . This production occurs after the first edition of the the echo signal offset is calculated through comparison of a signal of interest is separated from the first edition of the first edition of the echo signal against a second edition of the echo signal and after the second edition of the signal of echo signal , where the first edition of the echo signal is interest is separated from the second edition of the echo 55 collected with a first edition of a signal of interest from a first signal . The combined signal can be used in signal sensing , sensor , where the second edition of the echo signal is classification , and localization . collected with a second edition of the signal of interest from

FIG . 8 illustrates one embodiment of a system 800 a second sensor , where a network of the signal of interest is comprising the emission component 210 , the collection unknown , where the first edition of the signal of interest and component 220 , the computer - readable medium 230 , the 60 the second edition of the signal of interest are not identical , splitter component 410 , the offset component 420 , the and where the first sensor and second sensor are different compensation component 430 , the fusion component 710 , a sensors The compensation component 430 performs a com computation component 810 , and a threshold component p ensation for the second edition of the signal of interest 820 . A third edition of the echo signal with a third edition of through use of the echo signal offset . The processor 1010 the signal of interest can be collected by the collection 65 executes at least one instruction associated with the offset component 220 from a third sensor . The splitter component component 420 or the compensation component 430 ( e . g . , 410 separates the third edition of the echo signal from the the offset component 420 , the compensation component 430 ,

US 10 , 079 , 703 B1 12

the offset component 420 and the compensation component signal from the first edition of the signal of interest occurs 430 , the offset component 420 and another component , the along with separating the second edition of the echo signal compensation component 430 and another component , the from the second edition of the signal of interest occurs . At offset component 420 and the compensation component 420 1340 , calculating an offset of the first edition of the echo and another component , etc . ) . 5 signal against the second edition of the echo signal takes

In one embodiment , the first edition of the signal of place . At 1350 , modifying the second edition of the signal of interest functions as a base signal . The second edition of the interest through use of the offset to produce a modified signal of interest can be modified such that it aligns with the second edition of the signal of interest takes place . At 1360 , base signal . In one example , the echo signal offset ( e . g . , a combining the first edition of the signal of interest ( e . g . , difference between the second edition echo signal and the 10 original first edition of the signal of interest or a modified first edition echo signal ) can be used to change the second first edition of the signal of interest ) and the modified second edition of the signal of interest to align with the first edition edition of the signal of interest to produce a combined signal of the signal of interest . of the signal of interest occurs .

FIG . 11 illustrates one embodiment of a system 1100 FIG . 14 illustrates one embodiment of a method 1400 comprising the offset component 420 , the compensation 15 comprising other actions 1410 - 1440 in addition to the vari component 430 , the processor 1010 , a match component ous actions 1310 - 1360 . At 1410 , determining a constellation 1110 , and a find component 1120 . The match component of the combined signal of the signal of interest occurs . At 1110 matches the signal of interest with a known signal after 1420 , matching the constellation of the combined signal of the second edition of the signal of interest is compensated the signal of interest with a constellation of a known signal The find component 1120 finds a known signal modulation 20 occurs . At 1430 , identifying a modulation scheme of the scheme of the known signal , where the known signal modu known signal along with designating the modulation scheme lation scheme is used to demodulate the signal of interest . In of the known signal as the modulation scheme of the one embodiment , the match component 1110 is configured combined signal of the signal of interest takes place . At to match a constellation of the signal of interest with a 1440 , causing the combined signal of the signal of interest constellation of the known signal . 25 to be demodulated through use of the modulation scheme of

In one embodiment , the system 1100 can have access to the combined signal of the signal of interest occurs . a database of known signals ( e . g . , signal constellations with In one embodiment , calculating the offset of the first an associated modulation scheme ) . Once the editions of the edition of the echo signal against the second edition of the signal of interest are aligned , a constellation of the signal of echo signal comprises using a fast Fourier transform . In one interest can be determined ( e . g . , after fusing together the 30 embodiment , the first sensor is part of a first electronic editions of the signal of interest or before fusing together the device with a primary purpose other than functioning as a editions of the signal of interest ) and compared against sensor of the first edition of the signal of interest and the constellations of known signals in the database . When a second sensor is part of a second electronic device with a match is found ( e . g . , a highest match , a highest match that primary purpose other than functioning as a sensor of the reaches a threshold , etc . ) , a modulation scheme of the 35 second edition of the signal of interest , where the first matching signal can be designated as the modulation scheme electronic device and the second device are different elec for the signal of interest ( e . g . , if the network of the signal of tronic devices . interest is not know , then the modulation scheme of the In one embodiment , the computer - readable medium 230 signal of interest is also not known and thus a modulation of FIG . 2 can be configured to store computer - executable scheme is designated to demodulate the signal of interest ) . 40 instructions that when executed by the processor 1010 of

FIG . 12 illustrates one embodiment of a system 1200 FIG . 10 can cause the processor 1010 of FIG . 10 to perform comprising the offset component 420 , the compensation the method 1300 of FIG . 13 and / or the method 1400 . One of component 430 , the processor 1010 , the match component ordinary skill in the art will appreciate that the systems 1110 , the find component 1120 , a moment component 1210 , disclosed herein do not necessarily need to include the and a constellation component 1220 . The moment compo - 45 computer - readable medium 230 of FIG . 2 and / or the pro nent 1210 calculates a moment through use of the first cessor 1010 of FIG . 10 . One of ordinary skill in the art will edition of the signal of interest and the second edition of the further appreciate that the computer - readable medium 230 signal of interest , where the moment takes a summation of of FIG . 2 and the processor 1010 of FIG . 10 can function as a product produced from multiplying the first edition of the their own system . One of ordinary skill in the art will also signal of interest with the second edition of the signal of 50 appreciate that actions of methods described herein may be interest , The constellation component 1220 identifies the broken out into multiple actions and / or multiple actions may constellation of the signal of interest through use of the be combined into a single or simultaneous action . For moment . example , the action 1320 can be separated into two separate

FIG . 13 illustrates one embodiment of a method 1300 actions of collecting a first edition and a second edition . In comprising various actions 1310 - 1360 . At 1310 , causing an 55 one embodiment , components and other elements described emission of an echo signal to a first sensor and causing an herein can be part of a processing center ( e . g . , fusion center ) emission of the echo signal to a second sensor occurs , where and / or be retained in a housing . the first sensor and the second sensor are different sensors . What is claimed is : At 1320 , collecting a first edition of an echo signal with a 1 . A system , comprising : first edition of a signal of interest from the first sensor 60 an emission component configured to cause an emission occurs , where a network of the signal of interest is unknown . of an echo signal to a first sensor and a second sensor ; Also at 1320 , collecting a second edition of the echo signal a collection component configured to collect a first edition with a second edition of the signal of interest from the of the echo signal with a first edition of a signal of second sensor occurs , where a network of the signal of interest from the first sensor and configured to collect interest is unknown , where the first edition of the signal of 65 a second edition of the echo signal with a second interest and the second edition of the signal of interest are edition of the signal of interest from the second sensor ; not identical . At 1330 , separating the first edition of the echo and

US 10 , 079 , 703 B1 13 14

5

10

15

a non - transitory computer - readable medium configured to retain at least one instruction associated with the emis sion component or the collection component ,

where the first sensor and the second sensor are different sensors

where the first edition of the echo signal , the first edition of the signal of interest , the second edition of the echo signal , and the second edition of the signal of interest are used to detect the signal of interest and select a demodulation scheme for the signal of interest and 1

where the emission component , the collection component , and the non - transitory computer - readable medium are retained in a fusion center that does not function as a sensor . 15 2 . The system of claim 1 , comprising :

a splitter component configured to separate the first edi tion of the echo signal from the first edition of the signal of interest and configured to separate the second edition of the echo signal from the second edition of the 20 signal of interest ;

an offset component configured to perform a calculation of an echo signal offset , where the echo signal offset is calculated through use of the first edition of the echo signal and the second edition of the echo signal ; and 25

a compensation component configured to perform a com pensation for an offset of the first edition of the signal of interest against the second edition of signal of interest through use of the echo signal offset .

3 . The system of claim 2 , comprising : 30

a calculation component configured to perform a math ematical operation upon the first edition of the signal of interest after compensation and upon the second edition of the signal of interest after compensation to produce a mathematical result , and

a determination component configured to make a deter mination on a modulation scheme for the signal of interest based , at least in part , on the mathematical result , where the modulation scheme is employed to demodulate the signal of interest .

4 . The system of claim 3 , comprising : a demodulation component configured to demodulate the

signal of interest through employment of the modula tion scheme ; and

an output component configured to cause the signal of 45 interest to be outputted after being demodulated .

5 . The system of claim 2 , where the calculation of the echo signal offset comprises calculation of a relative fre quency offset .

6 . The system of claim 5 , where the calculation of the 50 echo signal offset comprises calculation of a relative phase offset .

7 . The system of claim 2 , comprising : a fusion component configured to produce a combined

signal through combination of the first edition of the 55 signal of interest with the second edition of the signal of interest after the first edition of the signal of interest is separated from the first edition of the echo signal and after the second edition of the signal of interest is separated from the second edition of the echo signal , 60 where the combined signal is configured for use in signal sensing , classification , and localization .

8 . The system of claim 2 , where the compensation com prises modifying the second edition of the signal of interest in accordance with the echo signal offset while the first 65 edition of the signal of interest is unmodified in accordance with the echo signal offset .

9 . The system of claim 1 , comprising : a splitter component configured to separate the first edi

tion of the echo signal from the first edition of the signal of interest and configured to separate the second edition of the echo signal from the second edition of the signal of interest ;

an sample component configured to determine a sample status of the first edition of the signal of interest after the first edition of the signal of interest is separated from the first edition of the echo signal and configured to determine a sample status of the second edition of the signal of interest after the second edition of the signal of interest is separated from the second edition of the echo signal ;

an comparison component configured to make a threshold determination if the sample status of the first edition of the signal of interest is consistent with the second edition of the signal ;

a re - sample component configured to re - sample the sec ond edition of the signal of interest to a rate of the first edition of the signal of interest if the threshold deter mination is that the sample status of the second edition of the signal of interest is not at the same rate as the first edition of the signal of interest , where the re - sampled second edition of the signal of interest is lined up in time with the first edition of the signal of interest ;

a fusion component configured to produce a combined signal through combination of the first edition of the signal of interest with the re - sampled second edition of the signal of interest , and

a determination component configured to make a deter mination on a modulation scheme for the signal of interest based , at least in part , on the combined signal .

10 . The system of claim 1 , where the first sensor is part of a first electronic device

with a primary purpose other than functioning as a sensor of the first edition of the signal of interest and

where the second sensor is part of a second electronic device with a primary purpose other than functioning as a sensor of the second edition of the signal of interest , where the first electronic device and the second device are different electronic devices .

11 . The system of claim 1 , where the emission component is configured to cause

emission of the echo signal with a signal of interest request signal to the first sensor , where the emission component is configured to cause emission of the echo signal with the signal of interest request signal to the second sensor ,

where the first sensor sends the first edition of the echo signal with the first edition of a signal of interest that is collected by the collection component in response to the signal of interest request signal , and

where the second sensor sends the second edition of the echo signal with the second edition of a signal of interest that is collected by the collection component in response to the signal of interest request signal .

12 . A method , comprising : causing , by way of a fusion center that does not function

as a sensor , an emission of an echo signal to a first sensor ;

causing , by way of the fusion center , an emission of the echo signal to a second sensor that is different from the first sensor ;

collecting , by way of the fusion center , a first edition of the echo signal with a first edition of a signal of interest from the first sensor ; and

35

40

16 US 10 , 079 , 703 B1

15 collecting , by way of the fusion center , a second edition edition of the echo signal with a second edition of the of the echo signal with a second edition of the signal of signal of interest from the second sensor ; and interest from the second sensor , a processor configured to execute at least one instruction

where the first edition of the echo signal , the first edition associated with operation of the emission component or of the signal of interest , the second edition of the echo 5 the collection component , signal , and the second edition of the signal of interest where the first edition of the echo signal , the first edition are employed to detect the signal of interest and select of the signal of interest , the second edition of the echo a demodulation scheme for the signal of interest . signal , and the second edition of the signal of interest 13 . The method of claim 12 , comprising : are employed to detect the signal of interest and select detecting the signal of interest through employment of the 10 first edition of the echo signal , the first edition of the a demodulation scheme for the signal of interest , signal of interest , the second edition of the echo signal , where the emission component the collection , component , and the second edition of the signal of interest ; and and the processor are retained in a fusion center that

selecting a demodulation scheme for the signal of interest does not function as a sensor . through employment of the first edition of the echo 15 18 . The system of claim 17 , comprising :

signal , the first edition of the signal of interest , the a detection component configured to detect the signal of

second edition of the echo signal , and the second interest through employment of the first edition of the edition of the signal of interest . echo signal , the first edition of the signal of interest , the

14 . The method of claim 13 , comprising : second edition of the echo signal , and the second demodulating the signal of interest in accordance with the 20 edition of the signal of interest ; and

demodulation scheme ; and a selection component configured to select a demodula tion scheme for the signal of interest through employ outputting the demodulated signal of interest .

15 . The method of claim 12 , comprising : ment of the first edition of the echo signal , the first separating the first edition of the echo signal from the first edition of the signal of interest , the second edition of

edition of the signal of interest ; 25 the echo signal , and the second edition of the signal of separating the second edition of the echo signal from the interest .

second edition of the signal of interest ; 19 . The system of claim 18 , comprising : calculating an echo signal offset through use of the first a demodulation component configured to demodulate the

edition of the echo signal and the second edition of the signal of interest in accordance with the demodulation echo signal ; and scheme ; and

performing a compensation for an offset of the first edition an output component configured to output the demodu of the signal of interest against the second edition of lated signal of interest .

20 . The system of claim 17 , comprising : signal of interest through use of the echo signal offset . 16 . The method of claim 15 , a separation component configured to separate the first where the calculating of the echo signal offset comprises 35 edition of the echo signal from the first edition of the

calculating a relative frequency offset and signal of interest and configured to separate the second where the calculating of the echo signal offset comprises edition of the echo signal from the second edition of the

calculating a relative phase offset . signal of interest ; 17 . A system , comprising : a calculation component configured to calculate an echo an emission component configured to cause an emission 40 signal offset through use of the first edition of the echo

of an echo signal to a first sensor and cause an emission signal and the second edition of the echo signal ; and of the echo signal to a second sensor that is different a compensation component configured to perform a com from the first sensor ; pensation for an offset of the first edition of the signal

a collection component configured to collect a first edition of interest against the second edition of signal of of the echo signal with a first edition of a signal of 45 interest through use of the echo signal offset . interest from the first sensor and collect a second * * * *

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