Patent Publication Number: US-2023164498-A1

Title: Binaural hearing system having two hearing instruments to be worn in or on the ear of the user, and method of operating such a hearing system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of copending application Ser. No. 17/190,680, filed on Mar. 3, 2021, which claims the priority, under 35 U.S.C. § 119, of German patent application DE 10 2020 202 725.0, filed Mar. 3, 2020; the prior applications are herewith incorporated by reference in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a method for operating a binaural hearing system for assisting the sense of hearing of a user, having two hearing instruments worn in or on the ear of the user. The invention furthermore relates to such a binaural hearing system. 
     The term hearing instrument generally refers to an electronic device which assists the sense of hearing of a person (who is referred to hereinafter as a “wearer” or a “user”) wearing the hearing instrument. In particular, the invention relates to hearing instruments which are configured to entirely or partially compensate for a hearing loss of a hearing-impaired user. Such a hearing instrument is also referred to as a “hearing aid.” In addition, there are hearing instruments which protect or improve the sense of hearing of users having normal hearing, for example to enable improved speech comprehension in complex hearing situations. 
     Hearing instruments in general, and especially hearing aids, are usually de-signed to be worn in or on the ear of the user, in particular as behind-the-ear de-vices (also referred to as BTE devices) or in-the-ear devices (also referred to as ITE devices). With respect to their internal structure, hearing instruments generally include at least one (acousto-electrical) input transducer, a signal processing unit (signal processor), and an output transducer. In operation of the hearing instrument, the input transducer receives airborne sound from the surroundings of the hearing instrument and converts this airborne sound into an input audio signal (i.e., an electrical signal which transports information about the ambient sound). This input audio signal is also referred to hereinafter as the “received sound signal”. The input audio signal is processed (i.e., modified with respect to its sound information) in the signal processing unit in order to assist the sense of hearing of the user, in particular to compensate for a hearing loss of the user. The signal processing unit outputs a correspondingly processed audio signal (also referred to as the “output audio signal” or “modified sound signal”) to the output transducer. In most cases, the output transducer is designed as an electro-acoustic transducer, which converts the (electrical) output audio signal back into airborne sound, wherein this airborne sound—modified in relation to the ambient sound—is emitted into the auditory canal of the user. In the case of a hearing instrument worn behind the ear, the output transducer, which is also referred to as a “receiver,” is usually integrated outside the ear into a housing of the hearing instrument. The sound output by the output transducer is conducted in this case by means of a sound tube into the auditory canal of the user. Alternatively, the output transducer can also be arranged in the auditory canal, and thus outside the housing worn behind the ear. Such hearing instruments are also referred to as RIC (“receiver in canal”) devices. Hearing instruments worn in the ear, which are dimensioned sufficiently small that they do not protrude to the outside beyond the auditory canal, are also referred to as CIC (“completely in canal”) devices. 
     In further constructions, the output transducer can also be designed as an electromechanical transducer which converts the output audio signal into structure-borne sound (vibrations), wherein this structure-borne sound is emitted, for example into the skull bone of the user. Furthermore, there are implantable hearing instruments, in particular cochlear implants, and hearing instruments, the output transducers of which directly stimulate the auditory nerve of the user. 
     The term “binaural hearing system” refers to a group of two hearing instruments which cooperate to supply the two ears of the user. In addition to these two hearing instruments, such a binaural hearing system can optionally comprise one or more further electronic devices, for example a remote control, a charging device, or a programming device for the hearing instruments. In modern hearing systems, a control program, in particular in the form of a so-called app, is often provided instead of a remote control or a dedicated programming device, wherein this control program is designed for implementation on an external computer, in particular a smartphone or tablet. The external computer itself is thus regularly not part of the hearing system and in particular is generally also not provided by the producer of the hearing system. 
     The modification of the input audio signal is regularly carried out in modern hearing instruments by means of digital signal processing algorithms. In this case, signal processors are usually used which include at least one programmable subunit, in which the signal processing is carried out by software (i.e., by executing a computer program). The software (also referred to as “firmware”) installed in the hearing instruments is regularly divided into a plurality of software modules, i.e., into multiple functional units which each fulfill a specific function. Depending on the type of programming, these software modules can be provided in various forms, for example as subprograms (also: procedures, subroutines, or functions), objects or classes in the meaning of object-oriented programming, components in the context of a component model and/or as plug-ins, etc. 
     The progressive development of hearing systems results in the need to integrate a growing number of sometimes numerically complex and/or storage-space-intensive software modules into the hearing instruments of a hearing system. This collides with the circumstance that the resources claimed by the software modules, namely the available processing power, the available (temporary and persistent) storage space, and the available electrical energy, are only available to a greatly restricted extent in hearing instruments—which are expediently always small, battery-operated devices. 
     BRIEF SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a hearing system and method which overcome the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provide for a binaural hearing system that is particularly resource saving. 
     With the above and other objects in view there is provided, in accordance with the invention, a method of operating a binaural hearing system, the hearing system having two hearing instruments to be worn in or on a respective ear of the user, the method comprising: 
     modifying an audio signal in each of the two hearing instruments by way of a programmable signal processor of the respective hearing instrument with an execution of a plurality of software modules of firmware of the hearing system and outputting a modified signal by way of an output transducer of the respective hearing instrument; 
     asymmetrically distributing the execution of the software modules of the firmware on the two hearing instruments, to thereby selectively execute at least one of the software modules of the firmware in one of the two hearing instruments; 
     dynamically selecting upon a start or during an operation of the hearing system one of the two hearing instruments on which at least one of the software modules of the firmware is to be executed; and selectively executing the at least one software module on the selected hearing instrument. 
     In other words, the objects of the invention are achieved by a method for operating a binaural hearing system for assisting the sense of hearing of a user. The hearing system comprises two hearing instruments each worn in or on an ear of the user. In each of the two hearing instruments, an audio signal is modified by means of a programmable signal processor of the respective hearing instrument with execution of a plurality of software modules of firmware of the hearing system and out-put by means of an output transducer of the respective hearing instrument. The executed software modules of the firmware are distributed asymmetrically on the two hearing instruments, so that at least one of the software modules of the firmware is selectively executed in one of the two hearing instruments. For at least one of the software modules of the firmware, it is dynamically selected upon the start or in operation of the hearing system on which of the two hearing instruments this software module is to be executed. The at least one mentioned soft-ware module is then executed selectively on the selected hearing instrument. 
     The above-mentioned object is also achieved according to the invention by a bin-aural hearing system for assisting the sense of hearing of a user, wherein the binaural hearing system comprises two hearing instruments each worn in or on an ear of the user. Each of the two hearing instruments respectively includes a programmable signal processor to modify an audio signal, an output transducer connected to the signal processor to output the modified audio signal, and a data transmission unit for exchanging data with the respective other hearing instrument. Firmware is installed in the hearing system. This firmware comprises a plurality of software modules which are executable in the signal processors of the two hearing instruments. The software modules of the firmware are distributed or can be distributed asymmetrically on the two hearing instruments, so that in operation of the hearing system at least one of the software modules of the firmware is executed selectively in one of the two hearing instruments. The hearing system comprises for this purpose a distribution unit, which is configured to dynamically select for at least one of the software modules of the firmware upon the start or in operation of the hearing system on which of the two hearing instruments this software module is to be executed, and to effectuate the selective execution of this software module on the selected hearing instrument. 
     With respect to a binaural hearing system, the object is achieved according to the invention by the features of claim  6 . Advantageous embodiments or refinements of the invention, which are partially inventive as such, are represented in the de-pendent claims and the following description. 
     The invention generally relates to a binaural hearing system, wherein the hearing system includes two hearing instruments each worn in or on an ear of the user (a first hearing instrument for the left ear of the user and a second hearing instrument for the right ear of the user). Each of the two hearing instruments of the hearing system respectively includes at least one signal processor, and output transducer, and a data transmission unit for exchanging data (in particular wirelessly) with the respective other hearing instrument. The two signal processors are used to modify an audio signal to assist the sense of hearing of a user. The signal processors are programmable and thus each have a program-controlled processing unit, for example in the form of a CPU, and—as an integrated or external component—at least one data memory. The signal processors preferably each have a volatile operating memory here, in particular in the form of a RAM, for temporarily storing the respective program and audio data required in operation of the hearing system and furthermore preferably also a nonvolatile memory, for ex-ample in the form of an EEPROM, for persistently storing program data. The signal processors optionally additionally also contain a nonprogrammable functional unit, for example in the form of an ASIC. Each hearing instrument of the hearing system is expediently supplied with power by a battery. In addition, each hearing system expediently includes at least one input transducer. 
     The input transducers of the hearing system are in particular acousto-electrical transducers, which convert airborne sound from the surroundings into electrical input audio signals (to be processed by the signal processors). The output transducers are preferably designed as electro-acoustic transducers (receivers), which convert the audio signal modified by the associated signal processing unit into airborne sound. Alternatively, the output transducers are designed to emit structure-borne sound or to directly stimulate the auditory nerve of the user. The output transducers are each interconnected with the signal processor of the associated hearing instrument in order to output the modified audio signal. 
     The two hearing instruments of the hearing system are preferably constructed equivalently, in particular mirror symmetrically, with respect to their hardware structure. The signal processors of the two hearing instruments, and optionally also the input transducers, output transducers, data transmission units, batteries, and/or other hardware components (for example possible sensors), are preferably structurally equivalent (i.e., identical with respect to structure and type, in particular exchangeable) or mirror symmetrical. 
     The two hearing instruments of the hearing system are provided in particular in one of the structural forms described at the outset (BTE device having internal or external output transducer, ITE device, for example CIC device, hearing implant, in particular cochlear implant, etc.). The two hearing instruments are preferably also designed equivalently and in particular mirror symmetrically with respect to the external form. 
     The hearing system furthermore comprises software (referred to hereinafter as “firmware”), which comprises a plurality of software modules of the above-described type. The software modules are executable here in the signal processors of the two hearing instruments in order to modify the audio signals (in particular the input audio signals generated by the input transducers) or to fulfill another function required for the operation of the respective hearing instrument. 
     The signal processing functions implemented in the software modules of the firmware for modifying the audio signal comprise in particular frequency-selective amplification, dynamic compression, spectral compression, direction-dependent damping (beamforming), interference noise suppression (in particular active interference noise suppression or Active Noise Cancellation, abbreviated ANC), active feedback suppression (Active Feedback Cancellation, abbreviated AFC), wind noise suppression, speech activity recognition, and/or voice recognition. 
     The firmware furthermore preferably comprises at least one further software module which is not used directly for processing audio signals, but provides an auxiliary or infrastructure functionality for the audio signal processing. Such auxiliary functionalities comprise, for example classifying the acoustic environment by evaluation of the audio signals in order to set the signal processing in dependence thereon or the processing of sensor signals (for example signals of an accelerometer, gyroscope, magnetometer, GPS sensor, heart rate meter, thermometer, etc.), controlling functions for interacting with the user, etc. Infrastructure functionalities comprise, for example functions of an operating system of the respective signal processor, functions for installing firmware updates, functions for recording useful data (data logging), functions for activating the data transmission unit, etc. 
     According to the method, in operation of the hearing system, an audio signal is modified by means of the signal processor of the respective hearing instrument, wherein the modified audio signal is output by means of the output transducer of the respective hearing instrument. The software modules of the firmware executed for this purpose in the signal processors are distributed asymmetrically on the two hearing instruments, so that at least one of the software modules of the firmware is executed selectively in one of the two hearing instruments. The term “selective execution of a software module” is to be understood to mean that the relevant software module is executed exclusively in one of the two hearing instruments, while in the other hearing instrument neither an identical software module nor another software module fulfilling the same function is executed. Preferably, work results (i.e., operation results) and/or states of this software module executed selectively on one of the two hearing instruments are transmitted to the other hearing instrument. 
     According to the invention, a deviation is made from the typical paradigm of the hearing system programming, according to which software modules for fulfilling the same functions are implemented in parallel (and thus doubled) in both hearing instruments of a binaural hearing system. Due to the asymmetrical distribution according to the invention of the software modules, processing operations executed redundantly on both hearing instruments are (entirely or partially) avoided, whereby both processing power and also memory and power consumption are saved. On the one hand, this permits firmware of a given functional scope to be executed with comparatively small-dimensioned resources (processing power, temporary or persistent storage space, and/or electrical energy) of the hearing instrument, which in turn enables a particularly small implementation of the hearing instruments. On the other hand, firmware having particularly large functional scope may be implemented in a hearing system having given resources. 
     The software modules of the firmware to be executed are dynamically distributed at least in a specific proportion on the two hearing instruments. Specifically, at least one of the software modules of the firmware can be executed on each of the two hearing instruments in this case. In the course of the dynamic distribution of this at least one software module, one of the two hearing instruments is selected upon the start or in operation of the hearing system, and this software module is then selectively executed on the selected hearing instrument. In other words, it is dynamically selected upon the start or in operation of the hearing system on which of the two hearing instruments the at least one software module to be distributed is to be executed. On the basis of this selection, the execution of the at least one software module to be distributed is effectuated selectively (i.e., only) on the selected hearing instrument. The term “dynamically” means here that the de-scribed selection is changeable over time. The same hearing instrument is thus not always selected for the execution of the at least one software module to be distributed, but rather the hearing instruments alternate in the execution of this software module. This change can either take place in running operation of the hearing system or between successive operating phases between which the hearing system was switched off. 
     This dynamic distribution takes place in one advantageous embodiment as a function of the respective battery charge of the two hearing instruments. In this case, for example, a remaining operating time to be expected until the battery is exhausted is determined from the respective battery charge for each hearing instrument in consideration of the power consumption (i.e., the electrical power) of the software modules executed or to be executed thereon, and in each case the hearing instrument having the higher remaining operating time is selected for the software module to be selectively executed. 
     Multiple software modules of the firmware are preferably distributed on the two hearing instruments for respective selective execution. These software modules are distributed in particular in such a way that the respective remaining operating times of the two hearing instruments until the respective battery charge is exhausted are compared to one another. The existing energy resources of the hearing system are thus utilized particularly well. A premature failure of a single hearing instrument because of a discharged battery is thus counteracted. In other words, a particularly long total running time of the hearing system formed from the two hearing instruments is achieved. 
     Additionally or alternatively thereto, the dynamic distribution takes place according to the respective required processing power and/or the respective required operating memory space of the software modules to be executed. This procedure is particularly advantageous if the firmware has a chronologically varying requirement for processing power and/or operating memory in operation of the hearing system; for example, if at least one of the software modules of the firmware is not executed uninterruptedly, but only temporarily, or if at least one of the software modules requires a varying amount of processing power and/or operating memory space. The dynamic distribution takes place in particular in such a way that the demand for processing power and/or operating memory space for the software modules to be respectively executed on the two hearing instruments is balanced with one another, that both hearing instruments are thus loaded approximately equally. 
     The hearing system according to the invention is generally configured to automatically carry out the above-described method according to the invention. The software modules of the firmware thus are distributed or can be distributed asymmetrically on the two hearing instruments, so that in operation of the hearing system at least one of the software modules of the firmware is selectively executed in one of the two hearing instruments. The, or each, software module selectively executed on only one hearing instrument is preferably configured to transmit work results and/or states by means of the data transmission unit of the associated hearing instrument to the other hearing instrument. 
     With the above and other objects in view there is provided, in accordance with the invention, a binaural hearing system, comprising:
         two hearing instruments each to be worn in or on an ear of a user, each of said two hearing instruments having a programmable signal processor for modifying an audio signal, an output transducer connected with said signal processor for outputting a modified audio signal, and a data transmission unit for data exchange with the respectively other hearing instrument;   firmware having a plurality of software modules installed in the hearing system;   wherein the software modules are executable in said signal processors of said two hearing instruments;   wherein the software modules of the firmware are distributed or distributable asymmetrically on the two hearing instruments, so that in operation of the hearing system at least one of the software modules of the firmware is selectively executed in one of said two hearing instruments; and   a distribution unit configured, upon a start or in operation of the hearing system, to dynamically select for at least one of the software modules of the firmware on which of said two hearing instruments the at least one software module is to be executed and to cause the selective execution of the at least one software module on the selected hearing instrument.       

     In other words, the above-described embodiments of the method according to the invention correspond to corresponding embodiments of the hearing system according to the invention. The above statements concerning the novel method are correspondingly transferable to the hearing system according to the invention and vice versa. In one embodiment, the hearing system in particular includes a distribution unit, which is configured to dynamically distribute at least one of the software modules of the firmware in the above-described manner, i.e., to selectively assign this software module to one of the hearing instruments for execution upon the start or in operation of the hearing system. The distribution unit can fundamentally be implemented in the scope of the invention as a (nonprogrammable) electronic circuit. However, the distribution unit is preferably formed by one of the software modules of the firmware. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as being embodied in a binaural hearing aid system with two hearing instruments that are worn in or on the ear of the user and a method for operating such a hearing system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG.  1    shows a schematic illustration of a binaural hearing system formed from two hearing instruments; each of the two hearing instruments including a signal processor having a program-controlled processing unit, an operating memory, and a persistent memory; 
         FIG.  2    shows a schematic illustration for each of the two hearing instruments of the operating memory and the persistent memory and firmware of the hearing system formed from multiple software modules, wherein a part of the software modules of the firmware is randomly distributed asymmetrically on the two hearing instruments in order to be executed selectively in each case on one of the two hearing instruments; and 
         FIG.  3    shows, in an illustration according to  FIG.  2   , an alternative embodiment of the hearing system, wherein some of the software modules are dynamically distributed asymmetrically on the two hearing instruments by a distribution unit upon the start or in operation of the hearing system, in order to be selectively executed in each case on one of the two hearing instruments. 
     
    
    
     Parts and variables corresponding to one another are always provided with the same reference signs in all figures. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures of the drawing in detail and first, in particular, to  FIG.  1    thereof, there is shown a binaural hearing system  2  for assisting the sense of hearing of a user. The hearing system  2  comprises two hearing instruments  4   a  and  4   b  for supplying the left or right ear of the user, respectively. Each of the hearing instruments  4   a  and  4   b  is a BTE hearing instrument, wearable behind the respective ear of the user in the example shown here. In the preferred application, the hearing instruments  4   a  and  4   b  are hearing aids which can be used to at least partially compensate for a loss of hearing of the user. 
     Each of the two hearing instruments  4   a  and  4   b  comprises at least one micro-phone  6   a  or  6   b  (in the illustrated example in each case two microphones  6   a  or  6   b ) forming input transducers and a receiver  8   a  or  8   b  forming output transducers inside a housing  5   a  or  5   b , respectively. Each hearing instrument  4   a ,  4   b  furthermore comprises a battery  10   a  or  10   b  and a signal processing unit in the form of a digital signal processor  12   a  or  12   b , respectively. Each of the two signal processors  12   a ,  12   b  includes a programmable processing unit (referred to hereinafter as CPU  14   a  or  14   b ) and has a volatile operating memory in the form of a RAM  16   a  or  16   b  and a nonvolatile (persistent) memory in the form of an EEPROM  18   a  or  18   b , respectively. The RAM  16   a ,  16   b  and/or the EEPROM  18   a ,  18   b  are preferably integrated with the CPU  14   a ,  14  in one component. The CPU  14   a ,  14   b  and the respective associated RAM  16   a  or  16  and/or the respective associated EEPROM  18   a  or  18   b  can alternatively also be provided as separate components. 
     The signal processor  12   a ,  12   b  is respectively supplied from the battery  10   a ,  10   b  with an electrical supply voltage U. 
     In normal operation of the hearing instruments  4   a ,  4   a , the microphones  6   a ,  6   b  each receive airborne sound from the surroundings of the respective hearing instrument  4   a ,  4   b . The microphones  6   a ,  6   b  convert the sound into an electrical (input) audio signal I, which contains information about the received sound. The input audio signal I is supplied inside the hearing instrument  4   a ,  4   b  to the signal processor  12   a ,  12   b.    
     The signal processors  12   a  and  12   b  process the input audio signals I in the way described in greater detail hereinafter in order to compensate for the hearing loss of the user. Each signal processor  12   a ,  12   b  outputs an output audio signal O, which contains information about the processed and thus modified sound, at the receiver  8   a ,  8   b  of the respective hearing instrument  4   a ,  4   b . The receiver  8   a ,  8   b  converts the output sound signal O into modified airborne sound. This modified airborne sound is transmitted via a sound channel  22   a  or  22   b , which connects the receiver  8   a ,  8   b  to a tip  24   a ,  24   b  of the housing  5   a ,  5   b , and via a flexible sound tube (not explicitly shown), which connects the tip  24   a ,  24   b  to an earpiece inserted into the associated auditory canal of the user, into this auditory canal of the user. 
     Each of the two hearing instruments  4   a ,  4   b  furthermore comprises a data trans-mission unit, for example in the form of a magnetic-inductive transceiver unit (referred to hereinafter as MI transceiver  26   a ,  26   b ). In operation of the hearing system  2 , the signal processors  12   a  and  12   b  exchange data via the MI transceiver  26   a ,  26   b  and a wireless data transmission connection  28  established between these MI transceivers  26   a ,  26   b  and cooperate in this case in the processing of the input audio signals I. 
     The signal processors  12   a  and  12   b  of the two hearing instruments  4   a  and  4   b  are structurally equivalent. The hardware components of the hearing instruments  4   a  and  4   b  corresponding to one another, in particular, the input transducers  6   a  and  6   b , the output transducers  8   a  and  8   b , the batteries  10   a  and  10   b , and the MI transceivers  26   a  and  26   b , are each also embodied as structurally equivalent or mirror symmetrical to one another. 
     In the signal processors  12   a  and  12   b , the processing of the input audio signals I is controlled by firmware  30  illustrated in simplified form in  FIG.  2   , which is di-vided into a plurality of executable software modules installed in the hearing instruments  4   a  and  4   b . The term “firmware” refers generally here to the entirety of the software modules installed in the two hearing instruments  4   a  and  4   b . The individual software modules each form delimited subunits of the firmware  30 , for example in the form of individual objects or components. In this case, each soft-ware module implements a specific function in conjunction with the processing of the input audio signals or another function required for the correct operation of the hearing instruments  4   a  and  4   b , in particular an auxiliary function for the audio signal processing or an infrastructure function as described above. 
     In more detail, the firmware  30  comprises a number of software modules (in the example according to  FIG.  2   , the software modules  32 ,  34 ,  36 ,  38 ), which are installed two times, namely in a first instance in the hearing instrument  4   a  and in a second instance in the hearing instrument  4   b . These software modules  32 - 38  form, for example:
         an operating system for the respective signal processor  12   a  or  12   b,      a function for frequency-selective amplification of the respective input audio signal I as a function of audiogram data, which characterize the hearing loss of the user; the two instances of the relevant software module installed in the hearing instrument  4   a  or in the hearing instrument  4   b , respectively, are parameterized differently, namely using the audiogram data for the respective associated ear of the user,   a function for the dynamic compression of the respective input audio signal I; the two instances of the relevant software module (in a way respectively adapted for the hearing loss of the left ear or the hearing loss of the right ear of the user) are preferably also differently parameterized in this case,   a function for ascertaining the charge level of the respective battery  10   a  or  10   b,      etc.       

     The firmware  30  furthermore comprises multiple software modules (in the example according to  FIG.  2    the software modules  40 ,  42 ,  44 ,  46 ,  48 ,  50 ,  52 , and  54 ), which are only installed once, namely either in the hearing instrument  4   a  or in the hearing instrument  4   b . In the illustrated example, the software modules  40 ,  44 ,  50 , and  52  are only installed in the hearing instrument  4   a , while the software modules  42 ,  46 ,  48 , and  54  are only installed in the hearing instrument  4   b . In other words, the software modules  40 ,  42 ,  44 ,  46 ,  48 ,  50 ,  52 , and  54  are asymmetrically distributed on the hearing instruments  4   a  and  4   b . In the example according to  FIG.  2   , this distribution is static and is defined by the producer in the development stage of the firmware  30 . The firmware  30  is thus divided into two invariable subgroups  56  and  58 , of which the subgroup  56  (comprising the software modules  32 ,  34 ,  36 ,  38 ,  40 ,  44 ,  50 , and  52 ) is associated with the left hearing instrument  4   a  and the subgroup  58  (comprising the software modules  32 ,  34 ,  36 ,  38 ,  42 ,  46 ,  48 , and  54 ) is associated with the right hearing instrument  4   b.    
     The asymmetrically distributed software modules  40 - 54  form, for example
         a function for recognizing a walking movement by analyzing the input audio signals I of at least one of the hearing instruments  4   a ,  4   b  and/or possibly by analyzing the signals of an internal or external movement sensor,   a function for ascertaining a degree of activity of the user by analyzing the input audio signals I of at least one of the hearing instruments  4   a ,  4   b  and/or possibly by analyzing the signals of an internal or external movement sensor,   a function for classifying a hearing situation by analyzing the input audio signals I of at least one of the hearing instruments  4   a ,  4   b,      a function for statistically registering characteristics of the acoustic surroundings of the user on a longer timescale (for example for registering the background noise) by analyzing the input audio signals I of at least one of the hearing instruments  4   a ,  4   b,      a function for recognizing a head turn of the user by analyzing the input audio signals I of at least one of the hearing instruments  4   a ,  4   b  and/or possibly by analyzing the signals of an internal or external movement sensor,   a function for ascertaining the reverberation duration by analyzing the input audio signals I of at least one of the hearing instruments  4   a ,  4   b,      etc.       

     The subgroups  56  and  58  are preferably composed in such a way that the soft-ware modules respectively contained therein each in total have an approximately equal demand for electrical power, processing power, and/or operating memory in operation of the hearing system  2 . 
     In  FIG.  2   , the EEPROM  18   a  and  18   b  and the RAM  16   a  and  16   b  are shown by way of example for each hearing instrument  4   a  and  4   b . It is apparent from this illustration that only the software modules of the respective associated subgroup  56  or  58 , respectively, are persistently stored in the EEPROM  18   a  and  18   b  of each hearing instrument  4   a  or  4   b . The two subgroups  56  or  58  are moreover selected in such a way that they require an approximately equal persistent memory space on the respective associated hearing instrument  4   a  or  4   b.    
     After the switching on of the hearing instrument  4   a , the software modules  32 ,  34 ,  36 ,  38 ,  40 ,  44 ,  50 , and  52  of the subgroup  56  are loaded from the EEPROM  18   a  into the RAM  16   a  (which is indicated in  FIG.  2    by an arrow  60   a ) and executed in the CPU  14   a . Similarly, after the switching on of the hearing instrument  4   b , the software modules  32 ,  34 ,  36 ,  38 ,  42 ,  46 ,  48 , and  54  of the subgroup  58  are loaded from the EEPROM  18   b  into the RAM  16   b  (which is indicated in  FIG.  2    by an arrow  60   b ) and executed in the CPU  14   b.    
     In operation of the hearing instruments  4   a  and  4   b  the software modules  32 - 38  executed in the two hearing instruments  4   a  and  4   b  exchange data—if necessary—via the MI transceivers  26   a ,  26   b  and the data transmission connection  28  with the respective other hearing instrument  4   b  or  4   a , which is illustrated by arrows  62  in  FIG.  2   . The software modules  40 - 54  only executed selectively in one of the hearing instruments  4   a  or  4   b  also transmit data (namely the work results respectively generated by these software modules  40 - 54 ) via the MI transceivers  26   a ,  26   b  and the data transmission connection  28  to the respective other hearing instrument  4   b  or  4   a , which is illustrated by arrows  64  in  FIG.  2   . 
       FIG.  3    shows an alternative embodiment of the hearing system  2 , in which—contrary to the embodiment according to  FIG.  2   —the software modules  40 - 54  are dynamically distributed on the hearing instruments  4   a  and  4   b  upon the start and in operation of the hearing system  2 , in order to be selectively executed on the respective assigned hearing instrument  4   a ,  4   b . In contrast to the static distribution according to  FIG.  2   , in the case of the dynamic distribution according to  FIG.  3   , the association of the software modules  40 - 54  with the hearing instruments  4   a  and  4   b  is not fixedly predetermined, but rather can be changed—in particular also in running operation of the hearing system  2 . This dynamic distribution is performed by a further software module of the firmware  30 , which is referred to hereinafter as the distribution unit  66 . 
     Also contrary to the embodiment according to  FIG.  2   , in the hearing system  2  according to  FIG.  3   , preferably the entire firmware  30  is stored in each case in both the EEPROM  18   a  of the hearing instrument  4   a  and also in the EEPROM  18   b  of the hearing instrument  4   b , so that program data of software modules does not have to be transmitted between the hearing instruments  4   a  and  4   b  in order to start the respective software module. Alternatively, however, the firmware  30  can also only be stored in one EEPROM  18   a  or  18   b  or can be distributed on both EEPROMs  18   a  and  18   b.    
     The distribution unit  66  is preferably—similarly to the software modules  40 - 54 — executed selectively in one of the two hearing instruments  4   a ,  4   b . The selection of the hearing instrument  4   a ,  4   b , on which the distribution unit  66  is to be executed can be permanently predetermined by the producer. Alternatively thereto, the distribution unit  66  is always executed on the hearing instrument  4   a ,  4   b  of the hearing system  2  which is switched on first. 
     In the example according to  FIG.  3   , the distribution unit  66  is executed by way of example in the hearing instrument  4   a . After the switching on of the hearing instrument  4   a , in addition to the software modules  32 - 38 , the distribution unit  66  is therefore also loaded in the RAM  16   a . After the switching on, the software modules  40 - 54  are distributed on the hearing instruments  4   a  and  4   b  by the distribution unit  66  either according to a permanently predetermined scheme or in the way set last (before the prior switching off). For this purpose, the distribution unit  66  (as indicated by an arrow  70  in  FIG.  3   ) causes the respective software modules, which are to be distributed on the hearing instrument  4   a  or the hearing instrument  4   b , to be loaded into the respective associated RAM  16   a  or  16   b  from the EEPROM  18   a  and the EEPROM  18   b.    
     During the operation of the hearing system  2 , the distribution unit  66  ascertains the charge level of the batteries  10   a ,  10   b  of the two hearing instruments  4   a ,  4   b , calculates therefrom—for example by extrapolation of the time change of the charge levels—for each hearing instrument  4   a  and  4   b  a remaining operating time to be expected in each case until the exhaustion of the respective battery  10   a ,  10   b , and compares these remaining operating times. 
     If the distribution unit  66  establishes upon this comparison that the remaining operating times differ by more than a predetermined threshold value, the distribution unit  66  redistributes one or more of the software modules  40 - 54 , which previously ran on the hearing instrument  4   a ,  4   b  having the shorter remaining operating time, onto the hearing instrument  4   a ,  4   b  having the longer remaining operating time. For this purpose, the distribution unit  66  causes, on the one hand, the or each software module  40 - 54  to be redistributed to be loaded in the hearing instrument  4   a ,  4   b  having the longer remaining operating time from the EEPROM  18   a ,  18   b  therein into the respective RAM  16   a ,  16   b  and executed and, on the other hand, stops the execution of this software module  40 - 54  on the hearing instrument  4   a ,  4   b  having the shorter remaining operating time. In  FIG.  3   , such a redistribution is indicated by way of example for the software module  52 , the execution of which is stopped in this example—indicated by an arrow  72 —on the hearing instrument  4   a  and is started on the hearing instrument  4   b . If necessary, states and/or parameter values of the software module  40 - 54  to be redistributed (in the example thus of the software module  52 ) are transmitted from the previously assigned hearing instrument  4   a ,  4   b  to the hearing instrument  4   a ,  4   b  assigned in future (in the example thus from the hearing instrument  4   a  to the hearing instrument  4   b ), so that the software module  40 - 54  can continue the previous function seamlessly, i.e., without information loss or changes of the properties, after the redistribution. 
     The above-described method is repeated by the distribution unit  66  continuously or at regular or irregular time intervals. In this case, the distribution unit  66  always redistributes enough of the software modules  40 - 54  that the remaining running times of the two hearing instruments  4   a  and  4   b  are equalized to one another. 
     The distribution of the software modules  40 - 54  is thus progressively adapted to changing charge levels of the batteries  10   a ,  10   b . In this way, a premature failure of one of the hearing instruments  4   a ,  4   b  due to discharged battery  10   a ,  10   b  is avoided and therefore the hearing system  2  can be used for a particularly long time without having to replace the batteries  10   a ,  10   b  or—if possible—recharge them. 
     In refined embodiments of the hearing system  2 , the dynamic distribution of the software modules  40 - 54  is additionally optimized in such a way that the processing power and/or the operating memory which is respectively required by the software modules associated with each of the hearing instruments  4   a ,  4   b  is approximately equalized between the hearing instruments  4   a ,  4   b.    
     It will be understood that, while the invention is particularly clear from the above-described exemplary embodiments, it is not restricted by these exemplary embodiments. Rather, further embodiments of the invention can be derived by a person skilled in the art from the claims and the above description. 
     The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:
       2  hearing system     4   a , 4   b  hearing instrument     5   a , 5   b  housing     6   a , 6   b  microphone     8   a , 8   b  receiver     10   a , 10   b  battery     12   a , 12   b  signal processor     14   a , 14   b  CPU     16   a , 16   b  RAM     18   a , 18   b  EEPROM     22   a , 22   b  sound channel     24   a , 24   b  tip     26   a , 26   b  MI transceiver     28  data transmission connection     30  firmware     32  software module     34  software module     36  software module     38  software module     40  software module     42  software module     44  software module     46  software module     48  software module     50  software module     52  software module     54  software module     56  subgroup     58  subgroup     60   a , 60   b  arrow     62  arrow     64  arrow     66  distribution unit     70  arrow     72  arrow   I input audio signal     0  output audio signal   U supply voltage