Title of Invention

ADAPTIVE FILTERING FOR WIRELESS COMMUNICATION

Abstract

A wireless communication device receives audio data from a base station via a radio frequency (RF) communication link (i.e., a forward link) and transmits audio data to the base station via the RF communication link (i.e., a reverse link). The wireless communication device uses the inherent func- tionality of the reverse link, including an audio input device (120) to determine whether the wireless communication device is operating in a high noise environment. A signal analyzer (124) analyzes the audio signal on the reverse link and determines whether the ambient noise level exceeds predetermined threshold. If so, the signal analyzer (124) activates a filter (126) to filter the audio signal being provided to an audio output transducer (122). Band limiting the audio signal provided to the audio output transducer (122) improves intelligibility of the audio signal in the presence of noise.

Full Text

SYSTEM AND METHOD FOR ADA]?! JVE EQUALIZATION IN A W:[RELESS COMMUNICATION SYST EM FIFXD OF THE [NVENTION The present mvention relates generally to wireless cornr'im^Jcation systems and, more particularly, to a system and method for adaptive equalization in a comn^iiuiication liiik m a wireless coniDaunica lion system. BACKGROLfND OF THE INTVENTION Wireless communication devices, such as cellular telephones, are u'idely used as a replacement for conventional telephone systems. C>ne advantage of the wireless communication devices is their portability. The i:5er can operate the wireless coiiununication device from virtually any point on earth. One coirmon use of wireless conimxmication devices is in the .automobile. However, the ?..tnbient noise level in an aulornobile can :Tiake satisfactory operation of the wireless comniunicalion device -difficult or impossible. Similarly, operation in other high noise envirc'nments, such as a factory or in a crowd {e,g,, at a baseball game) CBJ\ aho make satisfactory operation difficult or impossible. 1-lG. 1 provides an illustration of a wireless conimunication i.ysten\ 2 that comprises a mobile unit 4 and one or more base station trar\sceiver systems (BTS) 6. Foi the sake of simplicity, only one BTS 6 is illastrated in FIG. 1. Tlie B7'$ 6 is coupled to a cell tower 8 and ei5lablishes a commtLnkation link 10 v/ith the mobile unit 4. As t}\o>e skilled in the art can appreciate, the conimunication link 10 is illusd'atlve of muJliple J'orms of conimiudcation that occur betv/een the mobile unit 4 and the BTS 6, For example^ typical cotnmuriication between the mobile unit 4 and the BI'S 6 are in the form of cudio conununications- However, the communication link 10 is initi.illy set up using other form5 of cormnLaiication that occur over a control channel. These specific steps used to establish the communication link 10 between the mobile lurdi 4 and the BTS 6 are known in tlie art and need not be described in any detail hereir^ Furthermore, the specific steps used to establish the communication link 10 may var\^ from one tA-pe of xvireless system to another. For example, analog cellular com::nuni<:c may have one protocol ased to establish the comjnunicoition liril while digital commujiication devices sudi as a cdma wu-eless systen m an entirely different used estal: thie comxriunication link. however steps required by any systirm communication link are well la and need not be dtjscribed herein.> The data transmitted from the BTS 6 to the mobile unit 4 is some times referred to as a forward conuT.u:iicaaoi\ link 12 while thie data transmitted from the mobile oiit to the BTS is referred to as a reverse communication link 14, In a high noise environment, an audio signal transmitted on the forward linJc 12 can be difficult for the user to hear- Accordingly, there is a significant need for a system and method that processes the audio data received on the fonvard link 12 in a mamier that improves mtelligibili:)'. The present invention provides Ihis and othter advantages I'hat will be appatf-nt ixom the follo^ving detailed description and accojTipany ing figures. SUlvlMARY OF THE I>rvT.NTION "Rie present invention is embodied in a system and method for adaptive equali5:ation in a wireless con-uwinication system. In one embodiment tha wkeless cormnurucation device h^ansmits data to and receives dara from a remote location and comprises a signal analyser to analyze data to be transmitted to the remote location and to determine therefrom a noise characteristic present at a location of the mobile unit. Tlie signal analyzer generates signals indicative of the noise ciiaracteristic. J^iii equalizer is selectively activated by the generated signals to aher specbral characteristicir of d^ita received from the remote location in response to the generated signals. In one embodiment, the signal analyzer may periodically 3naly.2e the data to be transmitted to the remote location and generate periodic sigi'ials indicative of the noise characteristic. The equalizer is an adaptive equalizer and periodically alters tl^e spectral cliaracteristics of !-he received data in response to the signals periodically generated by the :;ugnal analy.:er. iri one embodiment, the equalizer may be a high pass j'ilter. The frequency response characteristic of Lie high pass filter may be adjusted to correspond to a frequency resporise characteristic of the output transducer. In some wireless devices^ a plurality of different outpu: devices may be coupled to the wireless conrjnunicahon device. EacJ-i external device has its own frequency response chai7;Cteristic. The frequency response characteristic of the equalizer may he selected to corresponci; to the frequency response characteristic of the selected output transducer. BRIEF DESCKir'T'IOM OF THE Dl^WINGS FIG. 1 illustrates, an exemplar}' ccmmunication link between a mobile iiiiit and a base station transceiver system (BTS). FIG. 2 is a functional block diagram of a system unplemeiifing the present invention. FIG. 3 is a frequency response plot implemented in an exemplary embodiment ot th-r^ present inver\tion. FIG. 4 is a flowchart illtistrating the operation of the present invejiHon. DETAILED DESCKIPTION OF llfE PREFEM^ED EMBODIMENTS The present inventior\ arialyzes audio data on the reverse link 14 (s^^e FIG. 1) and uses the results of the analysis to modify audio data on the fonvard link 12. Based Q:\ the analysis, the audio base band data on the forA'ard link 12 may be filtered to provide the user ivith a more intelli-gible audio signal This is particularly useful in a high ambient noise environment. The present invention analyzes audio data and thus may be readily implemented on any v/ireless coinmuxucation device. A short explanation of the ase of audio ddU on tlie forward lizik 12 (see PIG. 1) and the reverse link 14 may a5:>i$t in a better iaderst£inding of the present invention. Briefly, the forward link 12 cornpiises audio data modulated with a radio fre(.]U€'ncy (RP) carrier asing one of a number of different ] Although the system is described v/ith respect to the analysis of aiidio data, the essential analysis described below may be performed at other stages of data processing. For example, the analysis could be performed after the audio data on trie reverse iinl<: lias been modulated. thus the present invention is not limited solely to analysis of baseband audio data.> The present invention is embodied in a system 100 illustrated in the fimctional block diagram of FIG. 2. The system 100 includes a ■rentral processing uinit (CPU) 102, which controls operation of the system. Those skilled in the art v/iil appreciate that the CPU 102 is inte/^cled to encompa^is any processing device capable of operating the telecommiiiiication system. TTds ii'dudes rmcroprocessors, embedded controllers, applicatjon specific integrated circuits (ASICs), digital signal processors (PSPs), state machine:^/ dedicated discrete hard ware, and the Iik.e. The present invention is not iiinited by the specitic hardware component selected to implement the CPU 102. The system also preferably includes a memory 104, which may include both read-only memory (ROM) and random access memory (IL^iVl). The memory 104 provides iniitructioiis and data to the CPU 102. A pDrtion of the memoiy^ 104 may also include non-volahle random acce:>s men'iory (NP/RAM), such as flash jRAM, The system 100, which is t^-pically embodied in a wireless coramuxxication device r>uch ns tlie mobile unit 4 (see FIG. 1), also includes a housing 106 that contams a trartsnrdtter 108 and a receiver 110 to JJUOW trani-mission and reception of data, sudi as audio communications, between the system 100 and a remote location, such as the BTS 6, The iran^mitter lOS and receiver 110 may be coinbii^ed into a transceiver 112. z\n antenna 114 is attached to the housing 106 and electi-ically coupled to the transceiver 112. The operation of the transmitter 108, receiver 110, and antenna 114 is v^ell known in the art and need not be described lierein except as it r^'ilates specifically to the present invention. The system 100 also includes an audio input device 120, such as a microphone, and an audio output device 122, such as a speaker. The audio input device 120 and audio out}*?ut device 122 are generally rnouiUed m the housing 106. Additional components may also be used in a conventional rnamier dependmg on the type of wireless communication device. For example, an analog cellular telephone does not require the djgjiization of any audio data. In contrast, a digital wireless conimtuiiaiMon device will require additional components to convert tmalog audio data to digital fonn. Although not speciiicaiiy illustrated m PIG, 2, the audio input device 120 is coupled to an ar\alog-to-di)5itai converter (ADC) which converts analog audio signals to digital form if the system 100 is implemented iri a digital wireless communication devi<:e. the adc may be a portion of voice encoding system genedcally referred io as vocoder which encodes audio data in l fashion. siroilarly output device is coupled to digitai-to-analog converter converts digital analog foriti. for ttie sake clarity and dac are not shown fjncti block diagram fig. however operation e i well knov.ti art need described herein. noted above present invention does require inclusica these coniporients. wliich ls sometimes receiver corxfosed with replaced by an external will greater detail below.> The system 100 also includes a signal analyzer 124 to analyze :he audio data bemg sent to the transniitrer lOS for transmission on th^ ireverfe link 14 (see FIG. 1). As wOl be described in greater detail below, ihe si The system 100 fiirtiie^r comprises a filter 126 that operates in conjunclio:-^ with, the signal analyzer 124 to band limit the audio data received on. tlie forward liiik 12 (see FIG. 1). As will be dismissed in greater deUil below, the signal analyzer :i.24 determines when ambient noise levels are above a predetermined threshold and activates ttie filtei-126 when the ambient noise level is sufficiently tdgh. The filter 126 filters the In an exeinpiary embodiment the system 100 may be coupled io external audio devices via an input-output (I/O connector 128). The I/O connector 128 provides a port for audio input and output and may mrther provide access to control signals and other operational comj^onents, such as a keyboard (not show^i). The various components of the system 100 are coupled together by a bus system 130, v/hich may include a power bus, a control signc.l buy., and a station signal bus in addition to a data bus. However, for the sake of clarity the various buses are illustrated in FIG. 2 as the bus svstem 130. One skilled in the art will appreciate that tlie system 100 illustrated in FIG. 2 is a functional block diagram rather than a listing of specific ccimponents. For ex^niple, although the signal analyzer 124 and filter 126 are illustrated as two separate blocks within trie system 100, they may be in fact embodied in one physical component, such as a cigit£il sig-nal processor (DSP). They may also reside as program codes in the rnemor}' 104, such code being operated on by the CPU 102. The same conidderahons may apply ^ ofner components listed in the system 100 of FIG, 2. As noted above, the audio out|:)ut device 122 may be replaced b)' an external devic*/, such as an external speaker 150, a car kit speaker 152, a portable headset 154, or the like. The system 100 can use conventional technology to aiiiomalically identiiy wl'iich type of device is coupled to the I/O connector 128. For example, the system 100 automatically detects when tlae I/O coxinector 128 is covipled to the car kit speaker 152 and may further adjust parameters, such as volume level, to acco^mnodate comnection to the car kit speaker. Alternatively, if the system 100 determines that tlie portable headset 154 is coupled to tlxe I/O connector 128^ a different set of parameters, such as volume level, may be utilized for proper operation of the system v/ith the portable headset- As vvnll be described in greater detail belov/, the characterishcs of the f;ilterl26 may also be adjusted to operate most effectively with the particrular audio devicre. That is, one set of filter characteristics may be applied when the audio output device 122 is used, while other filter characteristics may be applied if an external device, such as the car kit speaker 152 or portable headset 154 is coupled to the I/O comiector 128. It has been determined that tiie intelligibility of audio signal generated by the audio output device 122 (or external devices 150-154) is adversely atfected by tlie presence oi ambient noise. For example, operation of the mobile uiiit iri an automobile may be margmaily affected :;f the automobile is not in niotion. However, if the automobile is in ir.otion and/or the windows are down, the fiigher level of ambient noise may cause pi'obleins with the car kit speaker 152. In the presence of such high, levels- of ambient noise, it is desirable to liniit the bandwidth of the audio data received by the receiver 110 that will be sent to the audio output device 122. In one embodiment, ti\e signal analyzer 124 merely analyzes the ::>veral]. signal sti^cngth dvd provides an indicator when the signal strerigth of the audio base band data on the reverse link 14 exceeds a predeterrriined thjr^i^sbold. Alternatively, the si;gnal analyzer 124 may additionally perl'or-m spectral analysis to deterinine the frequency component(s) that contribute to the high ambient noise level detected by the audio input device 120. ixi an exem]:?iary embodiment of the invention, the signal analyzer 124 determine!^ tlie level of ambient noise and activates the filter 126 if the ambient noise rises above a predstermiaed threshold. i\lthough it is possible to have a separate audio inpui system to measiire the level of ambient noise, the system 100 takes advar.tage of the audio signal processing capability already present in ihz mobile imit 4 that is required to transmit audio data on the reverse link 14 (see FIG. 1). As previously noted, components of the system 100 used in data processing on the reverse link 14 convprise the audio input device 120 (and associated ADC) and the bansrnitter lOS. However^ the signal analyzer 124 need only analyze audio base band data before it is processed by tlie traiismitter 108. The system components t^-pically associated with signal processing of data on the forward linlc 12 (see HG. 1) are the receiver 110 and the audio output device 122, Proper understanding of the present ijivention does not require detailed description of the operarion of the recei\'er i:iO. In a digital implementation of the system 100, tlie receiver 110 detectr> and decodes the Ki^ signal to produce a digital audio base band signal. Other well kjiown forms of data processing for error defce:tion/correction and the like may also be performed in a conventional manner. Ultimately, the data received on the forward iir\k ' 12 15. processed to produce digital audio data that is sent to the audio output device 122 via the DAC (not shown). In contrast, components typically involved in signal processing on the re\^erse lini: 14 comprise the audio ix^put device 120 and the transmitter 108. Audio signals/ such as speech sigi'ials, are detected by tt.e audio input device 120 and converted to digital form by the ADC (not sho\^m). The digital audio data is ultimately modulated by the trarrsmitter to generate an Ri^' signal that is transmitted fi*om the mobile Linit i to ttie BTS 6 vxa the reverse link 14. Again, the processing required to generate the l In some w^ireless commuriication devices, the mobile unit 4 is capable of detecting noise m the environzneiit and controlling the power level of the base band audio. For example, the CPU 102 may analyze the :>ignal to noise (S:N) ratio and adjust the power level of the signal delivered to the audio output device 122 based on the S:N ratio. In this .jxample, the power level of the audio signal w^ould be increased if the S:N ratio decreases. Conversely, ii the ambit^nt noise level decreases, the CPli 102 detects an mcrease in the S:N ratio and may decrease the power level to the audio outf)ui: device 122 accordirtgly.. In other wireless comrnimicatica devices, the CPU 102 may perform a sinxilar function in the jbrm of an audio automatic gain contiol (AGC) circuit. Tne CPU 102 or the signal analyzer 124 may detect noise in the envixoninent and control the power level of the sigi^al to the audio output device 122 as part of an AGC loop. AGC gain control is known in the art, and need not be described in. greater detail herein. In norm.aI operation {i.e., a lov; noise enviionnient), the bandwidth of t^ie audio signal is detei-mined by the frequency respoxise of the outp^it device {(^^v the audio device 122 or one of the external audio devi:'es 131)-154) as well as bandwidth liinitahons set by the system desij;n crittria. However, iho filter 126 alters the response of the system if activated by the 5i;gnal analyzer 124 in tlie presence of high levels of ambi ent noise. As noted above, the system 100 automatically detects when an external device, such as the car kit speaker 152 (see FIG, 2) or portable headset 154, is coupled to the I/O connector 128, Each device typicallv has ;.ts own characteristic resonant ft'equenc^^. The filter 126 may be implemeT:.ted as a high pass filter whose cutoff frequency may be adju.'ted to be slightly higher thai\ the resonance of the selected output transducer. For example, the audio output device 122 t)'pically has a resoriatice at appro^dmateiy 3C0 Hz - 400 Hz- V.^en the system 100 is implemented using tlie audio output device 122, the cutoff frequency of the filter 126 may be readily set at 500 Hz, as illustrated by a response curve 200 iii FIG. 3- In another exarx\ple, tl\e car kit speaker 152 may have a reionarJ: frequency of approximately 800 Hi:, If the car kit speaker 152 is coupled to the I/O coru\ector 128, the mobile unit 4 autornahcally detects the presence of tiie car kit speaker and can adjust the cutoff Ixequeucy of the filter 126 to be 1,000 Hz,, as illustrated by a response t.'urv'e 202. Other cutoff frequencies for the filter 126 may be selected based or. the resonance of the external speaker 150 and the portable headset ir>i, respectively. In this manner, the filter 126 is activated in the pres€tnce of high levels of ambient noise and reduces power delivered to the output transducer (e.g., tlie audio output device 122) so as to reduce the power delivered to the output transducer in the frequency range v/here excess signal power decreases intelligibility of the audio sigriaL Excels signal power at or below the resonance of the output transducer can result in sigruficaj\t audible distortion whdch can impair intelligibility. In an exemplarv^ embodiment, the CPU 102 and vSignal analyzer 124 are portions of a single DSP- The filter 126 is also readily implemented by the DSP. Ii\ one embodiment the filter 126 is tmplemenled as a third order hdgh pass filter whose cutoff frequency is :Uight'y liigher than the resonance of the outp^ut transducer {e.g., the audio output device 122), A third order high pass filter may be conveniently iniple.Tiented by tl\e DSP and can be customized with different cutoff irequerncies. Those skilled in the art will recognize that other filter tynpes may be used to implement the filter 126.^ For example, tiie signal analyzer 124 may perform a spectral analysis and tlie filter 126 may be implemented as a band pass filter or a notch filter to elirnii\ate unwanted nc»ise iignais detected by the signal analyzer. Alternatively/ the high pass filte.r illuiUrated in FIG. 3 may be impleinoitted as a lower or higher order filter. T!\G present mvention is not limited by the specific enibodirnent of die iilter 126. A reduction in power delivered to the output transducer {e.g., the iiudio output device j.22) may reduce power con^iuniption in the mobile ui'dt 4 (see FIG. 1) by reducirig the overall pov^'-er delivered to the out]:ut trarisducer. In addition, the filter 126 serves to reduce the physical damage to the outp-ut trarusdUwer {e,g., the audio output device 122) that may occur if an automatic gain control system is used in a lugh noise environment. That is, the AGC system would t^'pically increase the poW'Sr dL4ivered to the output b'ansducer {e^g,, the audio output device 12:!) in a high noise environment. Such high power levels may damage or reduce the life of the outyrut transducer. By band iimiting the power delivered to the output transducer, the system 100 reduces wear and tear on tf\e output transducer and may lengthen its operational lifetime. If used with an AGC system^ tJie band lirrating effects of the filter 126 may aiiov^ tine AGC circuit to deliver more power to the output transducer (e.g,, the audio output device 122) at useful frequencies. That is, fiequencies at or below the resonant frequency of the output transducer are greatly reduced thus improving intelligibility. The overall power to the output transducer may be subsequently increased such that more energy is delwered at usehd frequencies {ie., above the cutoff frecjusncy of the filter 126) tbius hirtlier improving inteliigibiliiy in a high noise environment. The operation oi' the system 100 is illustrated in the tlovv^chart of FJG. 4 vvnere at a start, 210, ihit system 100 is luider pov/er. In step 212, the signal snalyzer 124 monitors the ambient noise level. As noted above, the ivignal analyzer 124 takes advantage of the audio input processing i^leirents, such as the audio input device 120, ADC (not shov^n) and/or iihe VOCODER (not shown). In decision 214, the system 100 detennii^es whet.her the ambient noise level exceeds a predetermined tlireshold. If the ambient noise level is not above the predetermined tlireshold, the result of decision 214 is MO and in step 216, the system 100 deactivates the filter 126. If the ambient noise level is above the predetermined threshold, the result of decision 214 is YES and m step 218, the system 100 activ;ites the filter 126. Following the deactivation or activation of the filter 126 in steps 216 cind 218, respectively, the system 100 moves to decision 222 to determine if the signal level provided to the output trans^iucer (e.g., tlie audio output device 122) is satisfactory. It should be noted that tiiis is an ophonal step that may be in^plemented if the mobile unit 1 (see FIG^ 1) is equipped with an AGC system. Assuming the. mobije unit is equipped with an AGC s5'stem, the AGC system deter:nines in step 222 whether the signal to noise raho is satisfactory. If the si.jnal to noise ratio is imsatisfactory, th-t: result of decision 222 is NO and m step 224, the system 109 adjusts the gain of the signal provided to the output braasducer {e.g., the audio output device 122). If the signal to noise ratio is satisfactory/ tlie result of decision 222 is YES. In that event, or following tfie adjustment oi the gaiiii in step 224, the system returns to '>tep 212 and continues to monitor the ambient noise level. Thus, the systi^m lOlJ continuously analyzes ambient noise level iising circuit components frora the reverse link 14 (set- ¥1C^ 1) and based on analysis of tho audio i:iigrial ir. the reverse .'ink, may filter the audio signal on the forward link to make the audio sigivJ niore ir^telligible to the user in a high noise environrrtent. It is to be unden.tood that even though various embodiments and advar.tages of the present invention have been set forth in the foregoing description, the above disclosure is ilkistrative only, and changes may be made in detail yet rermiin vvil-hin the broad principles of the invention. Therefore, the present invention is to be limited only by the claLrns. CLAIMS What is claimed is: L A system for adap^lve equalL^ation in a wireless coTninunication system havm,g a base station traiisniitler and a base s;tatic)n receiver, the base station transmitter transmitting audio data on a forward coxiununication lini;, the base station receiver receiviiig audio data on a reverse communicahon link, the system comprising: a mobile unit having a Irarisrrdtter and a receiver to comraunicate with the base station on the reverse and forward communication links, respecbvely; a signal analyzer to analyze audio data to be tiansmitted on the ntwers^e. link and thereby detern\ine a noise characteristic present at a location of the mobile unit, the signal analyzer gei'verating signals indicative of tlie noise characteristic; and a filter to alter spectral characteristics of the audio data received from the base statioi: transmitter, the filter receiving the signals generated by the signal analyzer and altering the spectral cl\aracteristics of the audio data in response thereto. 2. The system, of claim ly fmrther comprising an output ttansclucer, having a frequency response characteristic, to generate ;^udib[e signals representative of tlie data received from the base station inransrutter, a filter response characteristic being selected based on the irequiincy response characteristic of the output transducer. 3. The syslem of claim 1, ftirther comprising a plurality of output transciuct^rs, each havii\g a {requsncy response^ characteristic, on* of wliich is selected to generate audible signals lepresentative of the cla:a reaiived from the l)ase staiion transmitter, the filter response cliaracteristic being adjustable ar\d being selected msod on the frequency response characteristic of tl^ie selected outj>ut transducer. 4. A system for adaptive equialization in a wireless cornmurdcation device that transmits data to and receives data fi'om a remote location, the system comprising: a signal analyzer to analyze data to be transmitted to the remote location and detenririe therefrom a noise characteristic: present at a bcatior. of the mobile unit, the signal imalyzer generating signals indicative of the noise characteristic; and an equalizer selectively activated by the generated signals to alter spccLral characteristics of data received from the remote location 'm respOl^&e thereto. 5. The system of claim 4 wherein the signal analyzer periodically analy^-res the data to be transmitted to the remote location and generates the signals indicative of the noise characterishc, the equal]L:?:er being an adaptive equalizer and periodically altering the specti-al characteiishcs of the received daia m response the signals per.odically generated by the signal analyzer. 6. The system oi cinim 4 wherein the remote location alter? a transnnit power level on a forward cornmimication lirik based on the signals periodically generated by the signal analyzer, 7. The system of claim 4 wherein the equalizer comprises ^\ high-pass filter. 8. Tlie system of claim 7, farther comprising an output trans ducery having a frequency resporise characteristic, to generate dudit>le sig:nals representative of the data received from the remote location, a high-pass filter response characteristic being selected based on the frequency response characteristic of the outjjut transducer. 9. The system of claim 7, further comprising a plurality of output transducers, each having a frequency resporuse cliaracteristic, one of wtuch is selected to generate audible signals representative of the data received from the remote location, the high-pass filter respoase characteristic being adjustable and being selected based on the frequency respoiise characteristic of the selected output transducer. 10. A method for adaptive equalization in a wireless commurication device transmits data to and receives data from a remote locaticn, the metl\od comprismg: analyzing data to be transmitted to the remote location and determining therefi"om a noise characteristic present at a location of the rnobilf unit; generating signals indicative of the noise characteristic; and altering spectral characteristics of data received from tlie remote location in response to the generation of signals indicative of the nois characteristic. 11. 7'he method of claim 10 wherein the data to be trariiiniitted to the remote location is periodicaliy analyzed and the signals indicative of the noise characteristic periodicaliy generatect the spectral characteristics of the received data being periodically altered in response die periodically generated sij^als indicative of the noise characteristic. 12. The method of claim 10, further comprising altering a transniit tjovv^er level on a forward conimunication link based on the pericdicaliy generated signals indicative of the noise characteristic, 13. The method of claim 10 wherein altering speclral chare cteristies of the data received from the remote location comprises fiigh-pass fiUering of the data received from thte remote locahon. 14. The method of claim 13 wherein the wireless conin\unication device comprises an outj^ut transducer, having a frequency re^^ponse characteristic, to generate audible signals representative of the data received from the remote location, the method furtJier ccii'iprising selecting a high-pass filter response characteristic based on the frequency response characteristic of the output transducer. 15. The method of claim 10 wherein the wireless comrrturdcation device comprises a plurality of output transducers, each having a frequency response characterisLic, one of which is selected tc generate audible signrdls representative of the data received from th«: remote location, the method further comprising altering specha] characteristics of data received from the remote location based on the fi-equenc)' response characteristic of the selected output tiansducer. A system for adaptive equalization in a wireless communication substantially as herein described with reference to the accompanying drawings. A method for adaptive e^^iialization in a wireless communication device substantially as *n described with reference to the accompanying drawings.

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