Patent Publication Number: US-2010130198-A1

Title: Remote processing of multiple acoustic signals

Description:
BACKGROUND OF THE INVENTION 
     Headset and other telephonic device designs must address background noise caused by a variety of noise sources in the user&#39;s vicinity. Such background noise may include, for example, people conversing nearby, wind noise, machinery noise, ventilation noise, loud music and intercom announcements in public places. These noise sources may either be diffuse or point noise sources. In the prior art, such acoustic interference is normally managed by (1) the use of a long microphone boom, which places the microphone as close as possible to the user&#39;s mouth, (2) a voice tube, which has the same effect as a long boom, or (3) a noise canceling microphone, which enhances the microphone response in one direction oriented towards the user&#39;s mouth and attenuates the response from the other directions. However, these solutions may not be compatible with stylistic and user comfort requirements of the headset. When using noise-canceling microphones, if the microphone is not properly positioned the noise reducing mechanism effectiveness is reduced. In these cases, additional background noise reduction is required in the microphone output signal. 
     In addition to point noise sources and diffuse noise sources, headsets and other telephonic device designs used for telephony must deal with the acoustic response from device speakers being detected by the device microphone and then sent back to the far-end speaker. Following delays inherent in the telecommunications circuit, this acoustic response may be detected by the far-end user as an echo of their own voice. As used herein, the “transmit signal” refers to the audio signal from a near end user, e.g. a headset wearer, transmitted to a far-end listener. The “receive signal” refers to the audio signal received by the headset wearer from the far-end talker. In the prior art, one solution to the echo problem is to ensure the acoustic isolation from the headset speaker to the headset microphone is sufficient to render any residual echo imperceptible. For example, one solution is to use a headset with a long boom to place the microphone near the user&#39;s mouth. 
     However, such a headset may be uncomfortable to wear or too restrictive in certain environments. Furthermore, many applications require a headset design that cannot achieve the acoustic isolation required, such as a headset with a very short microphone boom used in either cellular telephony or Voice over Internet Protocol (VoIP), or more generally Voice over Packet (VoP) applications. In these applications, the delay through the telecommunications network can be hundreds of milliseconds, which can make even a small amount of acoustic echo annoying to the far-end user. The required acoustic isolation is more difficult to achieve with boomless headsets, hands-free headsets, speaker-phones, and other devices in which a microphone and speaker may be in close proximity. One solution described in the prior art is to utilize an echo cancellation technique to reduce the acoustic echo. Such techniques are discussed for example, in U.S. Pat. No. 6,415,029 entitled “Echo Canceller and Double-Talk Detector for Use in a Communications Unit.” Noise reduction, echo cancellation, and other similar techniques may be implemented using digital signal processing (DSP) techniques. 
     In the prior art, DSP audio processing techniques such as those used in noise reduction algorithms or voice recognition are generally divided into two categories: imbedded device processing and server based processing. In imbedded device processing, the signal processing algorithms are typically executed “locally” on a relatively small mobile device such as a headset or cell phone that has limited size and battery power. Due to their limited size and battery power, such devices require the use of relatively small processors and have limited memory resources. As a result, the ability of such devices to perform memory intensive signal processing is limited. Furthermore, the mobile devices are typically much more cost sensitive than servers and typically only process signals for one device. 
     The imbedded device systems utilize simpler algorithms that can execute on the limited resources. These simpler algorithms are often limited to single inputs with nonrobust techniques. For example,  FIG. 1  illustrates a simplified block diagram of the components of a prior art headset  200 . Headset  200  may include a headset controller  226  that comprises a processor, memory and software. The headset controller  226  receives input from headset user interface  230  and manages audio data received from microphone  212  and audio from a far-end user sent to speaker  224 . The headset controller  226  further interacts with wireless communication module  234  to transmit and receive signals between the headset  200  and a base station. 
     Wireless communication module  234  includes an antenna system  236 . The headset  200  further includes a power source such as a rechargeable battery  228  which provides power to the various components of the headset. Wireless communication module  234  may use a variety of wireless communication technologies. The headset user interface  230  may include a multifunction power, volume, mute, and select button or buttons. Other user interfaces may be included on the headset, such as a link active/end interface. 
     The headset  200  includes a microphone  212  for receiving an acoustic signal. Microphone  212  is coupled to an analog to digital (A/D) converter  26  which outputs a digitized signal  217 . Digitized signal  217  is provided to a digital signal processor (DSP)  238  for processing to remove background noise utilizing a noise reduction algorithm. A processed signal is output from noise reducer for transmission to a far-end user via wireless communication module  234 . 
     The imbedded device processors do not have the resources to execute complex audio processing algorithms in real time. Such devices perform limited processing algorithms on the device and transmit the processed signal to a location remote from the device. The devices did not transmit multiple channels of acoustic data for remote processing. For remote clients on server based systems there were not enough channels or bandwidth available to transmit multiple channels of acoustic information. As a result, although server based processors have the capacity to run complex and robust algorithms, the algorithms were constrained to processing a single input channel. 
     With server based processing, the signals are processed by a server where size and power are not typically limitations and more robust algorithms can be used. The servers service multiple clients or can be purpose built for a single client device. The servers are not as cost sensitive as their imbedded device counterparts. 
     Many robust algorithms running on servers advantageously process multiple input signals. Although offering greater processing power, the server-based processing systems are constrained to operate on fixed systems where large processors are available, such as PC based systems. These systems can execute complex algorithms processing multiple inputs but were used with stationary rather than wireless mobile devices. 
     Accordingly, there has been a need for improvements in the processing of multiple acoustic signals. More specifically, there has been a need for improved systems and methods for processing of multiple acoustic signals in wireless products. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements. 
         FIG. 1  illustrates a simplified block diagram of the components of a prior art wireless headset implementing limited signal processing at the headset. 
         FIG. 2  illustrates a system for remote processing of multiple acoustic signals in one example of the invention. 
         FIG. 3  illustrates a simplified block diagram of the components of the mobile communication device shown in  FIG. 2 . 
         FIG. 4  illustrates a simplified block diagram of the components of the processing station shown in  FIG. 2 . 
         FIG. 5  illustrates one example of signal processing performed by a processing station. 
         FIG. 6  illustrates examples of telephone networks in which the present invention may be implements. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Methods and apparatuses for remote digital signal processing of multiple acoustic signals are disclosed. The following description is presented to enable any person skilled in the art to make and use the invention. Descriptions of specific embodiments and applications are provided only as examples and various modifications will be readily apparent to those skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed herein. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention. 
     Generally, this description describes a method and apparatus for transmitting, receiving, and processing multiple acoustic signals remotely from a wireless mobile communication device (also referred to herein as a client or remote device) at which the acoustic signals are received. The present invention is applicable to a variety of different types of mobile communication devices, including headsets and cell phones. While the present invention is not necessarily limited to such devices, various aspects of the invention may be appreciated through a discussion of various examples using this context. 
     According to an example of the invention, the system includes a wireless mobile communication device which transmits signals from multiple microphones to a server and processes them in real time or near real time at the server. Multiple channels of information are transmitted from the remote device to a processing station (also referred to herein as a fixed base or server) where the signals can be processed. The 802.11a and Bluetooth standards are two examples of wireless communication protocols that may be used. In one example, the system transmits each acoustic signal on a separate channel. In a further example, the system may use a single channel to transmit multiple acoustic signals. 
       FIG. 2  illustrates a system for remote processing of multiple acoustic signals in one example of the invention. The system includes a wireless headset  2 , processing station  4 , and a wireless protocol link  3  between the headset  2  and processing station  4 . For example, wireless protocol link  3  may be any low power, high quality RF link. In one particular example, wireless protocol link  3  is a Bluetooth link. 
     Wireless headset  2  may be boomless or include a short or regular length boom. Wireless headset  2  comprises two or microphones for receiving acoustic input and an audio speaker for outputting a voice output. Any wireless hands free device, handset or other telephonic device may be used in the invention in place of a wireless headset  2 . In operation, the wireless headset microphones receive undesired input from noise sources in addition to a desired user voice  6 . For example, as shown in  FIG. 2 , noise sources may be represented as a noise source x 1   8  and a noise source x 2   10 . Noise source x 1   8  and noise source x 2   10  may be either point noise sources or general background noise. In addition, the output of a far end user voice at the headset speaker may present an additional noise source at the headset microphones. 
     Processing station  4  is a computing device. Processing station  4  may be any electronic device capable of performing the processing functions described herein. For example, processing station  4  may be a personal computer, cellular telephone, PDA, or a base station coupled to a landline telephone. 
     Wireless headset  2  transmits multiple acoustic signals to processing station  4  over wireless protocol link  3  for processing. For example, processing station  4  may perform noise reduction processing. By performing noise reduction processing at the processing station  4 , the noise reduction power requirement is located at processing station  4 , where processing power is greater relative to headset  2 . Battery requirements remain low in headset  2 . 
       FIG. 3  illustrates a simplified block diagram of the components of the headset  2  shown in  FIG. 2 . Headset  2  may include a headset controller  26  that comprises a processor, memory and software to implement functionality as described herein. The headset controller  26  receives input from headset user interface  30  and manages audio data received from microphones  12  and  14  and audio from a far-end user sent to speaker  24 . The headset controller  26  further interacts with wireless communication module  34  (also referred to herein as a transceiver) to transmit and receive signals between the headset  2  and processing station  4  employing comparable communication modules. The term “module” is used interchangeably with “circuitry” herein. 
     Wireless communication module  34  includes an antenna system  36 . The headset  2  further includes a power source such as a rechargeable battery  28  which provides power to the various components of the headset. In a further example, the wireless communication module  34  may include a controller which controls one or more operations of the headset  2 . Wireless communication module  34  may be a chip module. Referring again to  FIG. 2 , processing station  4  includes a corresponding wireless communication module to allow communication or linking between the processing station  4  and the headset  2 . 
     Wireless communication module  34  may use a variety of wireless communication technologies. For example, wireless communication module  34  is a Bluetooth, Digital Enhanced Cordless Telecommunications (DECT), or IEEE 802.11 communications module configured to provide the wireless communication link. Bluetooth, DECT, or IEEE 802.11 communications modules require the use of an antenna at both the receiving and transmitting end. In one example, headset antenna system  36  is a diversity antenna. 
     The headset user interface  30  may include a multifunction power, volume, mute, and select button or buttons. Other user interfaces may be included on the headset, such as a link active/end interface. It will be appreciated that numerous other configurations exist for the user interface. The particular button or buttons and their locations are not critical to the present invention. 
     The headset  2  includes a microphone  12  and a microphone  14  for receiving audio information. For example, microphone  12  and microphone  14  may be utilized as a linear microphone array. In a further example, the microphone array may comprise more than two microphones. Microphone  12  and microphone  14  are installed at the lower end of the headset boom in one example. 
     Use of two or more microphones is beneficial to facilitate generation of high quality speech signals since desired vocal signatures can be isolated and destructive interference techniques can be utilized. Use of microphone  12  and microphone  14  allows phase information to be collected. Because each microphone in the array is a fixed distance relative to each other, phase information can be utilized to better pinpoint the location of noise sources and reduce noise. Although the use of two microphones may be described herein, headset  2  may be implemented with any number of microphones. 
     Microphone  12  and microphone  14  may comprise either onini-directional microphones, directional microphones, or a mix of omni-directional and directional microphones. Microphone  12  and microphone  14  detect the voice of a near end user which will be the primary component of the audio signal, and will also detect secondary components which may include background noise and the output of the headset speaker. 
     Each microphone in the microphone array at the headset is coupled to an analog to digital (A/D) converter. Referring again to  FIG. 3 , microphone  12  is coupled to A/D converter  16  and microphone  14  is coupled to A/D converter  18 . The analog signal output from microphone  12  is applied to A/D converter  16  to form individual digitized signal  20 . Similarly, the analog signal output from microphone  14  is applied to A/D converter  18  to form individual digitized signal  22 . A/D converter  16  and  18  include anti-alias filters for proper signal preconditioning. 
     Those of ordinary skill in the art will appreciate that the inventive concepts described herein apply equally well to microphone arrays having any number of microphones and array shapes which are different than linear. The impact of additional microphones on the system design is the added cost and complexity of the additional microphones and their mounting and wiring, plus the added A/D converters, plus the added processing capacity (processor speed and memory) required to perform processing and noise reduction functions on the larger array. 
     Digitized signal  20  and digitized signal  22  output from A/D converter  16  and A/D converter  18  are transmitted to processing station  4  using wireless communication module  34 . In one example, the wireless network over which headset  2  and the processing station communicate is referred to as a personal area network (PAN). Both the wireless communication module  34  and corresponding wireless communication module at charging station  4  have the capability to transmit and receive signals over the PAN. The PAN may use a variety of transmission networks, including radio-frequency networks. For example, the radio-frequency network could employ Bluetooth, 802.11, or DECT standards based communication protocols. However, the wireless network is not limited to PANs or these communication protocols. 
     In one example, wireless communication module  34  communicates over an RF network employing the Bluetooth standard with corresponding Bluetooth modules at the processing station. The Bluetooth specification, version 2.0, is hereby incorporated by reference. A prescribed interface such as Host Control Interface (HCI) is defined between each Bluetooth module. Message packets associated with the HCI are communicated between the Bluetooth modules. Control commands, result information of the control commands, user data information, and other information are also communicated between Bluetooth modules. For example, the Bluetooth network may use the headset profile or a variation thereof. 
     In one example, processing station  4  is a Bluetooth master unit and headset  2  is a Bluetooth slave unit. Processing station  4  assigns channel access priorities to headset  2  and sets the frequency-hopping sequence the headset  2  tunes to. Processing station  4  permits headset  2  to transmit by allocating slots for acoustic data traffic. Headset  2  contains a unique Bluetooth device address, which is a 48-bit IEEE address. Point-to-point time division duplex (TDD) communication is used between the headset  2  and the processing station  4 . A channel is divided into time slots, each of which is 625 microseconds in length. Processing station  4  utilizes up to three simultaneous synchronous connection-oriented (SCO) fill-duplex voice links with headset  2 . 
     In a further example, wireless communication module  34  communicates over a RF network employing the DECT standard with corresponding DECT modules at the processing station. The DECT standard is a wireless protocol designed to provide wireless communications for telecommunications equipment such as cordless phones. The DECT standard is promulgated by the European Telecommunications Standards Institute. It operates in the 1.8 GHz radio band, employing Time Division Multiple Access (TDMA) technology. DECT operates at speeds of 2 Mbps and is ideal for use in voice applications. DECT offers the advantages of low power consumption, enabling smaller batteries to be used in a wireless headset. In addition to offering multiple channels, DECT offers varying bandwidths by combining multiple channels into a single barrier. 
     In a further example, wireless communication module  34  uses an IEEE 802.11 (“802.11”) standardized network to transmit voice either within an enterprise (intranet) or over a wider area (internet) using VoIP technologies or converging a LAN with the telephony system within a company to provide wireless access to the public switched telephone network (PSTN) system. 
     The IEEE 802.11 wireless LAN standard addresses the basic transport of LAN data over a wireless medium. There are currently three variations of 802.11: IEEE 802.11a (5 GHz, 54 Mbps), IEEE 802.11b (2.4 GHz, 11 Mbps), and IEEE 802.11g (2.4 GHz, 54 Mbps). Streaming media applications, such as voice communication require a reliable and predictable data stream. Such reliability and predictability is provided by the ability to classify traffic and prioritize time-sensitive classes of traffic, referred to as QoS (Quality of Service). QoS is addressed by 802.11e. It includes more effective channel management, provides better power management for low power devices, specifies a means to set up side links to other 802.11 devices while simultaneously communicating with an 802.11 AP, and provides improvements to the polling algorithms used by access points. 
     802.11 LANs use a distribution system, also referred to as a backbone, to forward frames to their destination when several access points are connected to form a large coverage area, requiring communication between each access point to track the movements of mobile stations. In many embodiments Ethernet is utilized. The access points act as bridges between the wireless world and the wired world. Each access point has at least two network interfaces: a wireless interface that understands 802.11 and a second interface with wired networks. Typically, the wired interface is an Ethernet port and/or WAN port. Access points typically have a TCP/IP interface. The mobile stations may, for example, be wireless headsets. 
       FIG. 4  illustrates a simplified block diagram of the components of the processing station  4  shown in  FIG. 2 . Processing station  4  includes a wireless communication module  40 , controller  42 , and noise reducer  44 . 
     Digitized signal  20  and digitized signal  22  are received by wireless communication module  40  from wireless communication module  34  and provided to noise reducer  44  by controller  42 . Noise reducer  44  processes digitized signal  20  and digitized signal  22  to remove background noise utilizing a noise reduction algorithm. A processed signal  48  is output from noise reducer  44  for transmission to a far-end user. 
     Digitized signal  20  and digitized signal  22  corresponding to the audio signal detected by microphone  12  and microphone  14  may comprise several signal components, including user voice  6  and noise source x 1   8  and noise source x 2   10 . There is a time delay between digitized signal  20  and digitized signal  22  output resulting from the different physical location of microphone  12  and microphone  14  at headset  2 . 
     Noise reducer  44  may comprise any combination of several noise reduction techniques known in the art to enhance the vocal to non-vocal signal quality and provide a final processed digital output signal. Noise reducer  44  utilizes both digitized signal  20  and digitized signal  22  to maximize performance of the noise reduction algorithms. Noise reducer  44  may also utilize a far-end voice signal  46  in the noise reduction algorithms. Each noise reduction technique may address different noise artifacts present in the voice and noise signal. Such techniques may include, but are not limited to noise subtraction, spectral subtraction, dynamic gain control, and independent component analysis. 
     Referring to  FIG. 2  and  FIG. 4 , in noise subtraction, the noise source components x 1   8  and x 2   10  are processed and subtracted from digitized signal  20  and digitized signal  22 . These techniques include several Widrow-Hoff style noise subtraction techniques where the voice amplitude and the noise amplitude are adaptively adjusted to minimize the combination of the output noise and the voice aberrations. A model of the noise signal produced by noise source x 1   8  and noise source x 2   10  is generated and utilized to cancel the noise signal in the signals detected at the headset  2 . The synthesized noise model of noise source x 1   8  and x 2   10  represents the combination of the noise sources, where all the noise sources combined are treated as one noise source. 
     In spectral subtraction, the voice and noise components of digitized signal  20  and digitized signal  22  are decomposed into their separate frequency components and adaptively subtracted on a weighted basis. The weighting may be calculated in an adaptive fashion using an adaptive feedback loop. 
     Noise reducer  44  further uses digitized signal  20  and digitized signal  22  in Independent Component Analysis, including Blind Source Separation (BSS), which is particularly effective in reducing noise. 
     Noise reducer  44  may also utilize dynamic gain control, “noise gating” the output during unvoiced periods. When the user of headset  2  is silent, there is no output to the far end and therefore the far end user does not hear noise sources x 1   8  and x 2   10 . The noise reduction techniques described herein are for example, and additional techniques known in the art may be utilized. 
     In one example application, headset  2  is an 802.11a VOIP headset operating in a high background noise environment. One headset microphone is placed near the mouth to pick up the desired voice signal but also detects undesired ambient noise. A second headset microphone is placed to primarily detect ambient noise. The signals from both of these microphones are sent to a processing station where the ambient noise signal is subtracted from the voice signal to produce a clean voice signal for transmission. 
       FIG. 5  illustrates one example of signal processing performed by a processing station  4 . When multiple noise sources are present, blind source separation techniques are particularly effective in reducing noise. Referring to  FIG. 5 , an embodiment of the invention is shown illustrating an apparatus for noise reduction using blind source separation noise reduction. The apparatus receives individual digitized signals  20 ,  22  from a remote headset  2  and includes a beamform voice processor  108 , beamform noise processor  110   a , beamform noise processor  110   b , . . . beamform noise processor  110 N, voice echo controller  112 , noise echo controller  114   a , noise echo controller  114   b , . . . noise echo controller  114 N, transmit voice activity detector  116 , double talk detector  118 , noise reducer  120 , and far end receive voice activity detector  127 . One of ordinary skill in the art will recognize that other architectures may be employed for the apparatus by changing the number or position of one or more of the various apparatus elements. Although only two digitized signals  20 ,  22  are shown, additional digitized signals may be processed. 
     The individual digitized signals  20 ,  22  are applied to beamform voice processor  108 , beamform noise processor  110   a , beamform noise processor  110   b , . . . beamform noise processor  110 N. Beamform voice processor  108  outputs enhanced voice signal  109  and beamform noise processor  110   a ,  110   b , . . . ,  110 N outputs enhanced noise signal  111   a , enhanced noise signal  111   b , . . . , enhanced noise signal  111 N respectively. The digitized output signals  20 ,  22  are electronically processed by beamform voice processor  108  and beamform noise processor  110  to emphasize sounds from a particular location and to de-emphasize sounds from other locations. Through the use of beamform noise processor  110   a , beamform noise processor  110   b , . . . , beamform noise processor  110 N, remote microphones at a headset can be advantageously used to detect multiple point noise sources. Each beamform noise processor is used to focus on a different point noise source and can be updated rapidly to isolate additional noise sources so long as the number of noise sources is equal to or less than the number of noise beamformers N. 
     The output of beamform voice processor  108 , enhanced voice signal  109 , is also propagated along a voice processing path to voice echo controller  112 . The output of beamform noise processor  110   a , beamform noise processor  110   b , . . . , beamform noise processor  110 N is propagated along a noise processing path to noise echo controller  114   a , noise echo controller  114   b , . . . , noise echo controller  114 N. Echo controlled voice signal  113  and echo controlled noise signal  115   a ,  115   b , . . . ,  115 N are input to noise reducer  120 . 
     Microphone  12  and  14  at the remote headset receive signals from a voice source and one or more noise sources. The noise reducer  120  includes a blind source separation algorithm, as further described herein, that separates the signals of the noise sources from the different mixtures of the signals received by each microphone  12  and  14 . In further example, a microphone array with greater than two microphones is utilized, with each individual microphone output being processed. The blind source separation process separates the mixed signals into separate signals of the noise sources, generating a separate model for each noise source utilizing noise signal  115   a ,  115   b , . . .  115 N. 
     The output of noise reducer  120  is a processed signal  122  which has substantially isolated voice and reduced noise and echo due to the beamforming, echo cancellation, and noise reduction techniques described herein. Processed signal  122  is sent to a far-end user. 
     This example uses the features provided from several different signal processing technologies in a synergistic combination to provide an optimal voice output with minimal microphone background noise and minimal acoustic echo from the far end voice signal  124 . A judicious combination of signal processing technologies is utilized with a remote microphone array to provide optimal echo control and background noise reduction in the transmit output signal sent to a far-end user. 
     In a further example of the invention, the input data is converted from the time domain to the frequency domain utilizing an algorithm such as a Fast Fourier Transform (FFT). In the frequency domain the convolved processes of beamforming, echo control and noise reduction become simple addition functions instead of convolutions. In this embodiment the output of the final frequency domain step is transformed back to the time domain via an algorithm such as an Inverse Fast Fourier Transform (IFFT). Commercially available digital signal processor such as dsp factory&#39;s BelaSigna family, Texas Instruments TMS320C5400 family or Analog Devices ADSP 8190 family of products can be utilized to efficiently implement frequency domain processing and the required domain transforms. 
     Furthermore, the echo controller functions and beamforming function can be reversed and still operate within the spirit of the invention, as both functions are linear or near-linear operations. The advantage of one configuration, as opposed to the other, is the number of echo controller functions to be implemented is equal to the number of microphones. 
     Beamformers, echo controllers and noise reducers can be implemented as separate stages or convolved together in any combination as a single stage when implemented as linear processes. Convolving them together has the advantage of reducing the amount of processing required in the implementation, which reduces the cost, and it can reduce the end-to-end delay, also known as latency, of the implementation. This is useful for user comfort in telephony applications. Convolving them together requires a greater dynamic range. Commercially available digital signal processors such as processors in Texas Instruments family TMS 320C54xx or Analog devices ADSP family 819x can be utilized to implement the required signal processing. 
       FIG. 6  illustrates examples of telephone networks in which the present invention may be implemented. In one example configuration, a wireless headset  50  and a cell phone  56  establish short range wireless communications using a Bluetooth wireless link  70 . Cell phone  56  establishes wireless communications with a cellular base station  58  using a wireless protocol such as CDMA, GSM or other cellular standard known in the art. Base station  58  is coupled to a public switched telephone network (PSTN) node  60  for communication with a far-end user. In operation, wireless headset  50  transmits multiple channels of acoustic data over Bluetooth wireless link  70  to cell phone  56 . Cell phone  56  acts as a processing station as described herein to receive and process the multiple channels of acoustic data. 
     In a further example configuration, a wireless headset  54  and a landline telephone  68  establish short range wireless communications using a wireless link  74 . For example, wireless link  74  may be a DECT link. Although a DECT link is described, the wireless link  74  between the wireless headset  54  and landline telephone  68  may utilize any protocol capable of transmitting multiple channels of acoustic data, including for example, Bluetooth. Landline telephone  68  is coupled to PSTN node  60  for communication with a far-end user. In operation, wireless headset  54  transmits multiple channels of acoustic data over wireless link  70  to landline telephone  68 . Alternatively, wireless headset  54  may transmit multiple acoustic signals over a single high bandwidth channel. Landline telephone  68  is a processing station which receives and processes the multiple channels of acoustic data to generate a processed signal that is transmitted to the PSTN node  60 . Landline telephone  68  may include integrated hardware and software for performing the desired processing or may have a separate base station coupled to it. The DECT link may be utilized in a variety of application configurations, including for example cordless private branch exchange, wireless local loop, and GSM/DECT internetworking. 
     In a further example, a wireless headset  52  and an 802.11 access point (AP)  62  establish short range wireless communications using an 802.11 wireless link  76 . AP  62  may, for example, be a personal computer. Multiple acoustic signals are transmitted on the 802.11 wireless link  76  to AP  62  for processing. 802.11 access point  62  is connected to a LAN cloud  64  via a wired line. The system may further include a server/gateway  66  provided between LAN cloud  64  and PSTN node  60 . A wireless headset  53  may also establish short range wireless communications with AP  62  using an 802.11 wireless link  77 . AP  62  may therefore process multiple acoustic signals from more than one headset. Headset  52  and headset  53  both utilize 802.11 access point  62  and are therefore within a proximate geographic distance from each other defined by the 802.11 network parameters. 
     802.11 chipmakers include Intersil, Agere (Lucent), and Texas Instruments. Manufacturers of 802.11 access points include Orinco (e.g., AP 1000 Access Point) and Nokia (e.g., A032 Access Point). One of ordinary skill in the art will recognize that other Bluetooth, DECT and 802.11 architectures may be employed for the networks described herein by changing the position of one or more of the various network elements. 
     The various examples described above are provided by way of illustration only and should not be construed to limit the invention. For example, although processing related to acoustic signals and noise reduction is described, the systems and methods described can also be applied where correlation of multiple channels of any type of data, either analog or digital, is sent from one or more remote devices to one or more other devices for processing. Additional example applications include voice recognition for security and voice matching, voice dialing, and voice and video correlation. 
     Based on the above discussion and illustrations, those skilled in the art will readily recognize that various modifications and changes may be made to the present invention without strictly following the exemplary embodiments and applications illustrated and described herein. Such changes may include, but are not necessarily limited to: location of wireless communication modules or other components of the mobile communication device; versions and features of the Bluetooth version used, including Bluetooth enhanced data rate (EDR); number, placement, and functions performed by the user interface; wireless communication technologies or standards to perform the communication link between the mobile communication device and processing station; signal processors used; 802.11 access points used. The method of transmitting multiple acoustic signals from the mobile communication device to the processing station may vary in additional examples of the invention. For example, multiple channels or single channels of varying bandwidth may be used. Such modifications and changes do not depart from the true spirit and scope of the present invention that is set forth in the following claims. 
     While the exemplary embodiments of the present invention are described and illustrated herein, it will be appreciated that they are merely illustrative and that modifications can be made to these embodiments without departing from the spirit and scope of the invention. Thus, the scope of the invention is intended to be defined only in terms of the following claims as may be amended, with each claim being expressly incorporated into this Description of Specific Embodiments as an embodiment of the invention.