Abstract:
A portable communication device comprises a housing having therein: a microphone interface for receiving a first audio signal generated by a microphone connected thereto; an audio processing block in electronic communication with the microphone interface so as to receive the first audio signal, the audio processing block configured to generate a second audio signal corresponding to the first audio signal; a transmitter in electronic communication with the audio processing block so as to be configured to transmit the second audio signal; a receiver configured to receive third audio signals; an audio receive block in electronic communication with the receiver so as to generate a plurality of fourth audio signals, each fourth audio signal corresponding to a respective one of the third audio signals; and a speaker interface for connection to a speaker configured to emit audio corresponding to the fourth audio signals.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 62/182,956 filed on Jun. 22, 2015, which is hereby incorporated by reference in its entirety and for all purposes. 
     
    
     BRIEF DESCRIPTION 
       [0002]    Embodiments of the invention relate generally to wireless communication devices. More specifically, embodiments of the invention relate to wireless portable group communication devices and methods of their use. 
       BACKGROUND 
       [0003]    Many different communications devices currently exist. However, each is suitable only for certain applications. For example, cellular telephones are useful for one-to-one communication, but do not typically lend themselves well to group communication, i.e. conversations involving more than two individuals at the same time. Devices such as walkie-talkies and other two-way radio systems suffer from similar drawbacks, in addition to often being half-duplex (meaning that only one person may speak at a time) rather than full-duplex (allowing two or more individuals to speak simultaneously), cumbersome to use, not secure, providing poor voice quality, having limited range, and other drawbacks. Some telecommunications devices allow for conference calling, but these devices are typically not portable or require a backbone network such as a cellular network. 
         [0004]    Accordingly, ongoing efforts thus exist to create useful portable group communications devices. 
       SUMMARY 
       [0005]    The invention can be implemented in many ways, including as a portable communication device. 
         [0006]    In one embodiment, a portable communication device comprises a housing having therein: a microphone interface for receiving a first audio signal generated by a microphone connected thereto; an audio processing block in electronic communication with the microphone interface so as to receive the first audio signal, the audio processing block configured to generate a second audio signal corresponding to the first audio signal; a transmitter in electronic communication with the audio processing block so as to be configured to transmit the second audio signal; a receiver configured to receive third audio signals; an audio receive block in electronic communication with the receiver so as to generate a plurality of fourth audio signals, each fourth audio signal corresponding to a respective one of the third audio signals; and a speaker interface for connection to a speaker configured to emit audio corresponding to the fourth audio signals. 
         [0007]    The second audio signal and the third audio signals may be radio frequency (RF) signals, and may further have frequencies in a range of about 170 MHz to about 2.4 GHz. 
         [0008]    The audio processing block may be further configured to embed within the second audio signal an identifier corresponding to an identity of the device. 
         [0009]    The identifier may be one of a predetermined identification number, a key, a random number, or a media access control (MAC) address. 
         [0010]    The housing may comprise one or more of aluminum, rubber, a plastic, a glass, and steel. the audio processing block further comprises a voice activity detector configured to detect voice input from the first audio signal. 
         [0011]    The audio processing block may further comprise an audio encoder implementing an audio codec, the second audio signal including audio data compressed and encoded according to the audio codec. 
         [0012]    The audio receive block may further comprise a plurality of audio decoders each configured to receive one of the third audio signals and each implementing an audio codec, each fourth audio signal including audio data decoded according to the audio codec. 
         [0013]    The speaker interface may be a headphone interface. 
         [0014]    The third audio signals may be audio signals from multiple ones of the devices, the device further comprising a mixer in electronic communication with the audio receive block and configured to mix the fourth audio signals together so as to generate a mixed audio data stream, and wherein the emitted audio corresponds to the mixed audio data stream. 
         [0015]    The third audio signals may include audio signals from another audio source. 
         [0016]    The audio receive block may be further configured to generate comfort noise signals when no third audio signals are received. 
         [0017]    In another embodiment, a portable communication device comprises a housing, one or more digital processors positioned within the housing, and at least one memory in electronic communication with the one or more digital processors. The one or more digital processors and the at least one memory are collectively configured to implement simultaneous radio frequency voice communication between a user of the device and multiple other ones of the devices, by transmitting audio data corresponding to speech of the user to each of the other ones of the devices, receiving audio data from each of the other ones of the devices, mixing the received audio data, and transmitting the mixed audio data to the user so as to direct to the user combined and simultaneous speech of users of each of the other ones of the devices. 
         [0018]    The transmitting audio data may further comprise transmitting the audio data as radio frequency (RF) signals, and the receiving audio data may further comprise receiving the audio data as RF signals. 
         [0019]    The RF signals may be signals having frequencies in a range of about 170 MHz to about 2.4 GHz. 
         [0020]    The transmitting may further comprise embedding within the second audio signal an identifier corresponding to an identity of the device. 
         [0021]    The identifier may be one of a predetermined identification number, a key, a random number, or a media access control (MAC) address. 
         [0022]    The transmitting audio data may further comprise selecting a subset of the other ones of the devices, and transmitting to the other ones of the devices an indicator that the audio data is to be played only by devices of the subset. 
         [0023]    The transmitting audio data may further comprise compressing and encoding the audio data according to a predetermined audio codec. 
         [0024]    The receiving audio data may further comprise decoding the received audio data according to a predetermined audio codec. 
         [0025]    Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    For a better understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0027]      FIG. 1  conceptually illustrates a portable group communication device according to embodiments of the present invention; 
           [0028]      FIG. 2  illustrates use of multiple such portable group communication devices; 
           [0029]      FIG. 3  illustrates use of multiple such portable group communication devices in conjunction with cellular communication devices; 
           [0030]      FIG. 4  is a block diagram representation of components of a portable group communication device according to embodiments of the present invention; 
           [0031]      FIG. 5  is a flow diagram illustrating operation of one or more such portable group communication devices; 
           [0032]      FIG. 6  is a sequence diagram describing voice operation of multiple portable group communication devices of embodiments of the present invention; 
           [0033]      FIG. 7  is a sequence diagram describing a secure group admission process for such portable group communication devices; and 
           [0034]      FIG. 8  is a sequence diagram describing combined music and speech operation of such portable group communication devices. 
       
    
    
       [0035]    Like reference numerals refer to corresponding parts throughout the drawings. 
       DETAILED DESCRIPTION 
       [0036]    The various Figures are not necessarily to scale. All numerical values are approximate, and may vary. All examples of specific elements as well as their materials and compositions are to be taken as nonlimiting and exemplary only. Other suitable items, materials and compositions may be employed instead. 
         [0037]    In one embodiment, the invention involves a small, lightweight and portable telecommunications device that allows group communication among a number of users who may be mobile. Each user of a group has a device, and each device allows for full-duplex communication with any other user of the group. The devices thus allow for new forms of group communication. For example, a group of hikers, cyclists, skiers, or the like may be able to communicate with each other in remote areas, even if they are hundreds of yards apart from one another and/or outside visible range. Furthermore, every member of the group may simultaneously be able to communicate with every other member of the group, rather than only being able to communicate with one other member, Furthermore, every member of the group may be able to communicate in full-duplex mode, rather than only being able to communicate in half-duplex mode. 
         [0038]    These devices allow for many advantages. The small size and light weight of the devices allows users to easily carry and use these devices while on the move and engaged in physical and other activities for which carrying a device was previously inconvenient or awkward. The devices also allow communication over long ranges, such as radio range or the like. In this manner, groups of joggers, hikers, etc. may communicate with each other even if they are relatively far apart, at different elevations, behind obstacles such as walls, trees, etc. Devices of embodiments of the invention thus allow for many advantageous forms of group communication that were previously difficult if not impossible. For instance, groups of hikers may coordinate with each other to find a lost or injured member of their group even if that member is somewhat far away, or groups of cyclists may carry on a group conversation handsfree while riding. 
         [0039]      FIG. 1  conceptually illustrates a portable group communication device according to embodiments of the present invention. A group communications device  10  is shown next to, and for optional use with, a cellular telephone  20 . The group communications device  10  is a small, portable device that is of sufficiently small size and light weight to allow users to carry device  10  with them while remaining mobile and engaging in various activities, e.g. hiking, skiing, mountain climbing, etc. 
         [0040]    The device  10  allows users to communicate as part of a group, even without telephone  20 . In particular, the user may employ optional headphones  30  to speak/listen to other members of the group, with the device  10  acting as a wireless transceiver both transmitting the user&#39;s voice (or other) communication to the devices  10  of other members of the group, and receiving voice (or other) communication from the other users as well. This is conceptually illustrated in  FIG. 2 , which graphically shows use of multiple such portable group communication devices. In  FIG. 2 , four different devices  10  are shown as units  1 - 4 , each of which is a member of a group. As members of a particular group, each of these units  1 - 4  communicates with every other unit  1 - 4  in the group, as shown by the dotted lines. Thus, each unit  1 - 4  receives simultaneous communications from every other unit  1 - 4 , and also transmits communications to every other unit  1 - 4 . Accordingly, every user in the group may simultaneously communicate with every other member of the group. 
         [0041]      FIG. 2  illustrates use of multiple devices  10  by themselves, i.e. without any other communication devices such as telephones  20 . However, embodiments of the invention also allow for devices  10  to be used in conjunction with telephones  20  or other communication devices. As one example,  FIG. 3  illustrates use of multiple devices  10  in conjunction with cellular communication devices. Here, two users, (person  1  and person  2 ), use units  1  and  2  in conjunction with both their respective personal cellular phones  21 ,  22  and with headphones  31 ,  32 . In this configuration, person  1  and person  2  may communicate with each other via the headphones  31 ,  32  of their units  1 ,  2 . Such communication may be via, for example, voice, video or text. Phones  21 ,  22  may also perform other functions for person  1  and person  2 . For example, phones  21 ,  22  may play music for persons  1  and  2  respectively. In such case, the phones  21 ,  22  may play stored music or other audio to the respective units  1 ,  2  via wired connection or wirelessly, and this music may be relayed over headphones  31 ,  32  to the users. Similarly, cellular calls over the phones  21 ,  22  are passed through the units  1 ,  2  so that persons  1  and  2  may speak through the same headphones  31 ,  32 . Voice communication between the users may interrupt the music or other phone audio, so that the music or other audio signal playing on the phones  21 ,  22  is muted, its volume is lowered, or the music or other audio signal is paused so that speech relayed over the units  1 ,  2  is heard over the headphones  31 ,  32 . When the units  1 ,  2  stop receiving speech from other units, the volume may increase back to its previous level, or the music/audio signal is un-paused. That is, the users may receive audio from their phones  21 ,  22 , and may also converse with other users via units  1 ,  2  at the same time, with such conversations interrupting, mixing with or playing over the audio from phones  21 ,  22 . 
         [0042]    Attention now turns to the construction and configuration of devices  10  (i.e. units  1 ,  2  and the like).  FIG. 4  is a block diagram representation of components of a portable group communication device according to embodiments of the present invention. Here, device  10  is a small, portable communications device with radio communication capability, and includes a radio  100 , application processor  102 , memory  104 , audio codec  106 , and (optional) digital signal processor (DSP)  108 . As is known, these elements may be implemented as one or more integrated circuits packaged and soldered to a printed circuit board or other substrate, which connects to other elements such as a battery  110 , various buttons and status lights  112 , one or more interfaces  114 , and other electronic interface units  116 . As above, the device  10  may be connected to a phone  21 ,  22  and headphones  30 . 
         [0043]    The radio  100  is a radio frequency (RF) transceiver circuit capable of transmitting and receiving signals in an RF band. Any RF band is contemplated, including but not limited to sub-GHz, ISM, Wi-Fi, and other bands. As one example, transmission and reception may be at frequencies between about 170 MHz to about 2.4 GHz. In some embodiments, transmission and reception frequencies fall with the range of approximately 450 and approximately 900 MHz. The radio  100  may also transmit and receive according to any protocol, e.g. WiFi, Bluetooth or any other protocol. 
         [0044]    The application processor  102  may act as a system controller, and may run code implementing any desired features, including audio encoding/decoding, wind noise or other audio filtering processes, volume ramping, voice control command processing, etc. Alternatively, any one or more of these functions may be performed by other elements such as DSP  108 . 
         [0045]    The memory  104  is accessible by application processor  102 , and may store any code and data used by processor  102 . For example, memory  104  may store executable code for any of the above described features and for implementation of any of the operations described below. 
         [0046]    The audio codec  106  encodes and decodes the audio stream handled by device  10 , and may include the compression and decompression of digital audio data according to any desired audio file or streaming media audio coding format. Thus, also included in the device  10  but not shown are filter and digital-to-analog and analog-to-digital conversion circuits for converting analog audio received from the user via headphones  30  to a digital audio signal, as well as for converting digital audio signals received from another device  10  via the Antenna to an analog signal for playback through the headphones  30 . Such filter, digital-to-analog, and analog-to-digital conversion circuits are known. 
         [0047]    The device  10  may also include an integrated or built-in microphone instead of having a microphone in headphones  30 . As another alternative, the device  10  may utilize an external microphone array for improved acoustic performance by, for example, adaptively beam-forming towards the user&#39;s mouth. The device  10  may also include an integrated or built-in speaker instead of relying on those of headphones  30 . 
         [0048]    The battery  110  is a battery for a portable communications device, and stores charge sufficient to power device  10 . The battery  110  may be any known or other battery adapted for use in portable electronic devices. The buttons/status lights  112  may be any input devices sufficient to input any form of information to device  10 , as well as any output devices sufficient to display information. Exemplary input devices may include on/off/reset buttons, volume knobs or dials, and the like. Exemplary output devices may include light emitting diode (LED) indicators of various states, and the like. These input and output devices may be physical switches, icons on a display or touchscreen, or any other vehicle for input or output of any kind of information or commands. 
         [0049]    The interface  114  may be any interface for transmitting and receiving electronic or electrical signals, such as a universal serial bus (USB) interface or the like. The interface  114  may be in communication with the battery  110  and allow for charging thereof, with the processor  102  or memory  104  to allow for updates to firmware or other programs and code, and/or with any other components of device  10 . 
         [0050]    The other electronic interface units  116  may include any components or structures for conveying information to, or receiving information from, the user. For example, the interface units  116  may include a user interface which can be any one or more of a display such as a liquid crystal display (LCD) screen, touch sensitive display, organic light emitting diode (OLED) display, vibration unit for alerting the user by vibrating, speakers, microphones, a keyboard or keypad, and the like. Interface units  116  may also include interfaces to a mobile phone, media player, tablet computer, laptop computer, desktop computer, or any other electronic device. 
         [0051]    The interface units  116  may also include any one or more of various other hardware components that can be integrated into a mobile electronic device  10 . For example, any one or more of the following may be included: a second radio providing connectivity in a redundant or different frequency band, an external or internal antenna, near field communication (NFC) hardware, a motion sensor, accelerometer, gyroscope, global positioning system (GPS) receiver, thermometer, camera, speaker, microphone, light sensor, moisture sensor, barometer, magnetometer, touch sensor, battery level meter, fingerprint reader, solar cells for charging the battery  110 , mechanical (motion-based) chargers, and a depth gauge. Any interface for allowing connection to an external version of any of the above may also be included. 
         [0052]    The components of  FIG. 4  are encased within a housing, as shown in  FIG. 1 . The housing may be any lightweight and portable housing encasing and protecting the various components of  FIG. 4 . As nonlimiting examples, the housing may be made of a rigid plastic, a metal such as aluminum or steel, rubber, glass, or the like. In many embodiments, it is desirable for the housing and its various components therein to be sufficiently small and lightweight to be carried by users without difficulty during various physical activities. For example, the device  10  may be carried comfortably in a user&#39;s pocket during even strenuous physical activities. In some embodiments, it is desirable for the housing of device  10  to be waterproof. The housing may include mounts, brackets, or other fixtures allowing the device  10  to be mounted or carried in or on any equipment or part of the user. For example, fixtures allowing the device  10  to be mounted onto a helmet, carried in a pocket, hung on a backpack or a piece of clothing, extensible rod, or any other item are contemplated by various embodiments of the invention. In this manner, the device  10  may be carried or supported by the user in any manner, allowing for the device  10  to be positioned in any manner convenient for comfort, reception/signal strength (i.e. as high up above the ground as possible, to increase operating range), and the like. The housing may also be durable and rugged so as to be weatherproof, shock resistant, and able to withstand a wide range of impacts as well as temperatures during storage and operation. The housing may also include a replaceable or customizable cover for improved functionality and personalization. 
         [0053]    In another embodiment, the complete circuitry of device  10  may be integrated into another device, for example, a camera, a telephone or a tablet. In this case, device  10  may share some of the components, like display, keypad, buttons, battery, application processor, memory, DSP and software code with the other device. In another embodiment, the complete functionality of the device  10  may be implemented using the existing components in the other device without the need to add any additional components. 
         [0054]    The Antenna shown in  FIG. 4 , as well as any other internal or external antennas employed, may be any form of antenna. For example, antennas may be implemented as flexible printed circuit board trace antennas, coiled wires, extendable antennas, or any external antenna. Multiple such antennas are contemplated as well. The device  10  may be programmed to employ known active steering antenna techniques for improved data throughput. The device  10  may also use power amplifiers, range extenders or booster circuitry to enhance the range. 
         [0055]      FIG. 5  is a flow diagram illustrating operation of one or more devices  10 . More specifically, transmission and reception of voice/text information is illustrated. In  FIG. 5 , information flow is shown with reference to logical blocks represented in block diagram form. These blocks may be implemented in any one or more of the modules shown in  FIG. 4 , such as the radio  100 , application processor  102 , memory  104 , audio codec  106 , and/or DSP  108 . 
         [0056]    In operation, a user may communicate with another group member, either by speaking or texting. This may be carried out by speaking into the headphones  30  (or other microphone) of device  10 , or by typing text into device  10  through a unit  116  such as a keyboard GUI represented on a touch sensitive screen, or physical keys present on the outer surface of device  10 . In the case of audio, the user&#39;s voice or other audible noise is picked up by the microphone in headphones  30 , translated by voice receive (Rcv) circuitry into a pulse code modulated (PCM) or other digital audio stream, and transmitted to a Ping Pong buffer for buffering. Audio data are retrieved from this buffer at regular intervals to produce a data stream which is then processed to suppress noise, and sent to a voice activity detector (VAD) to determine whether the stream contains any speech samples. In this manner, the VAD can detect periods of silence. During such silence, data transmission can be halted or reduced to save battery power and channel bandwidth. In some embodiments, the VAD simply transmits voice input when it is detected. 
         [0057]    The audio stream is then sent from the VAD to an encoder for audio encoding. This encoder can utilize any codec for encoding, e.g. an open standard codec such as OPUS or the like. The encoder can also utilize a scratch buffer that can be implemented as a Ping Pong or other buffer. Once encoded, audio is encapsulated into packets, buffered in a queue such as a first in first out (FIFO) buffer, and transmitted in order to other devices  10  in the group. Encapsulation may include the addition of other data besides the audio data payload and conventional packet header information, such as a unique ID number identifying the device  10  transmitting the packet or the sequence number of the packet. 
         [0058]    Various actions may interrupt packet transmission. For example, user button presses (e.g., on/off/reset/mute, etc.) or the like may instruct a control protocol module to halt the queue, stopping packet transmission. Similarly, the control protocol may transmit other commands to various other modules in response to other button presses such as pairing, unpairing, volume up/down, and the like. 
         [0059]    Voice packets received from another device  10  are picked up by a wireless radio component, such as a CC1310 RF transceiver made by Texas Instruments Inc., which parses received packets, sends control packets to a control protocol module, and directs audio payload to a buffer. Multiple such buffers may exist, one for each member of the group, where the packets are directed to the appropriate buffer according to an identifier placed in the packet by the particular group member&#39;s device  10  and indicating the particular group member. 
         [0060]    Packets may be retrieved from each buffer and sent to a decoder such as an OPUS decoder for decoding the audio stream from each group member. The decoder may employ a scratch buffer such as a Ping Pong buffer if desired. Multiple decoders may be employed, one for each remote device, i.e. one decoder and buffer for each remote device to decode the voice data stream from each user in the group. The decoded data streams from these decoders are then mixed by a mixer, to form a single data stream. The mixer may combine the separate decoded data streams in any manner, such as by standard mixing, reducing the volume of audio from those units or nodes that are farther away, and may mix in audible indicators such as tones to indicate that a new user has joined, one has left the group, battery low indication, etc. 
         [0061]    The mixed data stream may then be sent to a volume scaler, which implements a scaling procedure that scales the magnitudes of the signals to an appropriate volume, for example a volume that is not excessively loud or too high to be supported by the output hardware. Scaling may be performed in any manner, such as in a manner that gives users an experience similar to multiple people speaking nearby each other. 
         [0062]    After scaling, the scaled audio stream is stored in a jitter buffer, which allows the device  10  to adjust for variations in packet arrival time, so as to provide users clearer audio without distortions caused by delayed or lost packets. A comfort noise generation (CNG) module then adds comfort noise if desired, to fill silent portions of the audio stream with a low but audible level of artificial noise that indicates to listeners that their connection is not lost. The resulting audio output is buffered in another Ping Pong buffer for output to the audio Tx hardware of the user&#39;s audio output device, such as headphones  30 . 
         [0063]    In this manner, multiple devices  10  can broadcast and receive audio among each other, with each device  10  broadcasting its audio to every other device  10  in the group, and also receiving audio from every other device  10  in the group. That is, one of ordinary skill in the art will observe that the audio transmission and receiving processes and operation described in FIG.  5  may be employed by each device  10  of a group, to transmit and receive audio among each of the devices  10  in the group.  FIG. 6  is a sequence diagram further describing such operation, illustrating voice transmission and reception between and among three users user 1 -user 3  and their three associated devices  10  device 1 -device 3 . In an environment with multiple users, more than one use case exists. For example, one user may wish to speak with the entire group, some users may wish to speak with only some subset of the entire group, and multiple users may wish to speak simultaneously.  FIG. 6  illustrates use of devices  10  in three such cases. In Case 1, user 1  may wish to speak to the entire group. In some embodiments, this may be the default case. Here, user 1  may speak into his or her device 1 , whereupon device 1  converts the received audio to a packet stream according to the process described above in connection with the top half of  FIG. 5 , and transmits this packet stream to both device 2  and device 3  (and in this example, device 3  receives the stream from device 2  where device 2  acts as a forwarding node). Both device 2  and device 3  receive and play back this audio stream for their users user 2  and user 3 , according to the receiving and decoding process described above in connection with the lower half of  FIG. 5 . 
         [0064]    In case 2, user 1  may wish to speak only with user 3 , and not with user 2 . User 1  would then issue a command to device 1  either via a button press or voice command, instructing device 1  that its audio is intended only for device 3 . User 1  then speaks to user 3 , with device 1  converting and transmitting a packet stream as above, and inserting an indication within the packets that they are intended only for device 3 . Packets received by device 2  are thus disregarded, while packets received by device 3  are decoded and played back as above. Alternately, device 3  may accept packets from device 2  but may elect to not process these packets. 
         [0065]    In case 3, multiple users (user 1  and user 3 ) may wish to speak at the same time. Both user 1  and user 3  speak into their microphones  30  and their devices device 1  and device 3  each encode and transmit their respective audio streams to the other devices in the group. While transmission is shown as being only from device 1  and device 3  to device 2 , actual transmission may be from each of device 1  and device 3  to the other devices in the group. Device 2  receives both audio streams, mixes them as above, and plays the mixed stream to user 2 . User 2  thus hears the voices of user 1  and user 3  simultaneously. 
         [0066]    Embodiments of the invention thus yield devices that allow for groups of people to be in radio contact with only each other, and to communicate over significant distances in a “group chat” manner in which, similar to a conference call, all users may speak and hear each other at the same time. In addition, users may choose to speak only to selected other members of the group. As the devices are small, lightweight and portable, they allow for groups of people to communicate with each other while carrying out other activities. For instance, groups of hikers, skiers, or cyclists, etc. may use the devices of embodiments of the invention to keep in contact with each other while performing these activities. As radio or other wireless communication is employed, the activities of the users do not need to be interrupted during communication. Thus, users may readily talk to each other while on the move, e.g. while they are all skiing, and may maintain communication even while considerable distances apart from each other and moving relative to each other. 
       Added Functionality 
       [0067]    It is noted that the architecture of devices  10  of embodiments of the invention allow for additional functionality besides that described above. Exemplary added functionality may be implemented by any one or more of the application processor  102 , audio codec  106 , and DSP  108  in known manner, and is listed and described as follows. If desired, devices  10  may implement any one or more of the following functions: 
         [0068]    SMF Protocol: Simple Multicast Forwarding (SMF) may be employed in encapsulation by device  10 . SMF provides certain advantages, e.g. it does not require route assessment (beacon) packets, may incur the same resource cost in the linear network case (where devices  10 , or nodes, are in a straight line) and collaborates to cover packet loss in dense configurations where nodes are all in close proximity or other configurations. SMF may increase the total packet count transmitted on the network; this can be addressed by increasing the packet data rate. 
         [0069]    Retransmissions: Devices  10  may employ any number of retransmissions for each packet in order to decrease the probability of lost packets. The number of retransmissions may be dynamically adjusted depending on factors like packet drops, network congestion, number of nodes in the network and battery power available. Retransmission criteria and number may be programmed into, for example, the control protocol module. 
         [0070]    Security: It may be desirable that communication within an associated group be performed in a secure manner. Accordingly, voice packets may be encrypted to ensure that devices that are not a part of the associated group cannot decrypt or understand the communication. Encryption may be performed as part of the encapsulation process. 
         [0071]    Interference Protection: It may be desirable for multiple associated groups to be able to co-exist in vicinity without interfering with each other. Multiple access protocols like FDMA, TDMA, CDMA or others may be used to ensure that the devices  10  can detect whether a received packet belongs to the associated group that it is a part of Devices  10  may also employ suitable collision detection and avoidance mechanisms like CSMA-CA (Carrier Sense Multiple Access-Collision Avoidance), frequency hopping or others to ignore transmissions from other devices that may be transmitting on the same wireless frequency. Embodiments contemplate implementation of any of these or other suitable protocols. 
         [0072]    Automatic selection of frequency based on geographic region: Each country has its own set of unlicensed radio bands. To work in multiple countries, devices  10  may support multiple industrial, scientific and medical radio (ISM) bands. Devices  10  may determine which country they are currently within through any source—cellular network, Wi-Fi, GPS or other mechanisms such as an associated configuration mobile application, manual setting or other scheme. 
         [0073]    Dynamic compression: Bandwidth: Generally audio compression has two potential side effects—power consumption, and loss of quality. If there is sufficient bandwidth available in the system, then compression need not be done at all. In practice, the bandwidth may be both limited and variable. A dynamic compression algorithm may be desirable to adapt to the available bandwidth so as to provide best quality and least power consumption, increasing battery life. This may be implemented by dynamically switching among the available voice encoding options (such as OPUS or other) including dynamically adjustable bitrate, audio bandwidth and frame size. That is, the application processor  102  may implement and switch among different encoders according to available bandwidth, and may also implement and switch among different decoders according to the encoding used for the data in received packets. 
         [0074]    Higher bitrate transmission may consume more battery. As the battery level drops, devices  10  may enter into a “battery save” mode where audio is progressively encoded at a lower bitrate, potentially enabling battery life to be extended at the expense of degraded audio quality. 
         [0075]    Generally, as the distance between devices  10  increases, the available bandwidth may decrease. A dynamic compression algorithm will adapt to the available bandwidth so as to preserve audio quality. 
         [0076]    In a congested wireless environment, it may be possible that the packet drop rate is high. In such a scenario, devices  10  may be programmed to decrease the bit rate and increase the number of retransmissions in order to increase the probability of their packets reaching the other devices  10  in the group. 
         [0077]    Messaging and Other Data Transfer: Devices  10  are not limited to voice communication—the system may also support, for example, text-based messaging using a user interface or app on a connected phone, where a cellular or Wi-Fi internet connection may not be available. Text may be input via the phone user interface, such as through a dedicated device  10  or other messaging app, and data may be sent over Bluetooth or analog cable to device  10  for transmission to other devices  10 . 
         [0078]    Video calls: Devices  10  may also support video communication, for example, a video call between two or multiple users. The video capture may happen through a camera integrated into device  10  as one of the units  116 , or via the phone/tablet/laptop interface. Similarly, the video playback may happen on the display attached to device  10  or through a phone/tablet/laptop interface. 
         [0079]    Voice Activated Transmission: voice activated transmission of speech when speech is detected. Devices  10  may employ known or other techniques and processes for voice activity detection. 
         [0080]    Audible Relative Position: when voice is rendered at a receiving device  10 , the relative position of the sender may be indicated. This may be useful, for example to avoid collisions while cycling or skiing. Position information may be encapsulated in transmitted packets according to, for example, information from a GPS module in the transmitting device  10 . 
         [0081]    Audible Relative Distance: when voice is rendered at a receiving device  10 , the relative distance among members of a group may be indicated by varying the volume of each of the rendered received voice streams. 
         [0082]    Voice Commands: Devices  10  may be programmed with code for recognizing simple spoken commands, for example “Mute Group” or “Speak Only With Jane”. Voice commands may be implemented by integrating an open source or commercial voice recognition SDK such as TrulyHandsfree from Sensory (sensory.com). 
         [0083]    Speech Volume Based Receiver Selection: Devices  10  can implement a scheme where the volume of a speaker is used to control which other devices  10  receive and render the speech—for example, quiet speech may be rendered at devices  10  within close proximity and louder speech at devices  10  further away, not unlike natural human speech among members of a group. More broadly, the volume of the speaker may be recognized and used by devices  10  to determine the volume of the reproduced audio, in any manner. 
         [0084]    Naming a Node: A unit can be “named” by a user, during for example a setup process in which an audible prompt may ask the user to name the unit and the voice recording is used to assign a name (for example “Jane”). The assigned audio name may be converted to text and used for voice controlled addressing by other members (“Speak only with Jane”) or for notifications (e.g. “Jane has left the group”). 
         [0085]    Private Talk: A user may initiate a private session with one or more selected members of the group, effectively temporarily muting the transmission of voice to or from members who are excluded from the group. This may also include functionality such as a “mute-all” where a user does not wish to participate in group communication. Muting can be done via any UI available on a device  10 , including via a voice command. In the latter case, multiple voice commands are recognized, such as muting a particular username, muting everyone, etc. There may also be a visible indication (For example “Red” LED on) to indicate a mute state. 
         [0086]    Broadcast Mode: Devices  10  may provide a “one-way” mode, for situations such as sports training where the instructor may be speaking to a group, including to other electronic devices (such as over Wi-Fi or Bluetooth or other protocol). 
         [0087]    Open Mode: Devices  10  can also provide a mode allowing any other device  10 , including units not explicitly paired or grouped, to communicate. 
         [0088]    Audio “Emoji&#39;s”: Devices  10  may allow sending out of audible notifications, for example two fast taps on a button may correspond to “Attention!”. Audible notifications may be stored in memory  104  and retrieved upon the proper button taps or other input. 
         [0089]    Alerts and Notifications: Devices  10  can be configured to generate alerts in the form of audible notifications (such as playing pre-defined sounds stored in memory  104 ), vibration alerts, LEDs or other means. This may be useful to indicate scenarios where the device  10  may be approaching an out-of-range situation, when a member has left the group, re-joined the group, switched off their unit and so on. This may be particularly helpful to overcome the problems found in two-way radios and other systems where a user may need to repeatedly ask “are you there”, leading to frustration. 
         [0090]    Link Quality: Devices  10  may provide a method to assess and indicate the link quality, to enable a member to perform certain actions, such as announcing to the group that they may be leaving the group or moving closer to other members. 
         [0091]    Location Indication: Devices  10  may provide a method to determine and indicate the locations of other devices  10 , or their relative location or orientation. This may be done by, for example, periodically or upon request transmitting GPS coordinates from each device  10 . 
         [0092]    Emergency Beacon: Devices  10  may incorporate an emergency indicator, such as via a panic button, to send a distress signal to all devices  10  within range. This may be useful in cases of emergency where the user may be immobilized or may need medical attention. In this case, the emergency signal may also be broadcast to all nearby devices  10  and not limited to units explicitly grouped. 
         [0093]    Motionless Indication: Devices  10  may also generate an alert to members of a group where one device  10  is motionless, submerged for more than a certain duration or in some other potentially distressed situation. 
         [0094]    Voice Snippets: Devices  10  may allow sending of short voice recordings between devices  10 . This may also include recording and playback of voice snippets when a member has left a group and later re-joined. 
         [0095]    Noise reduction: Devices  10  can implement noise reduction techniques, including wind-noise and other ambient noise reduction DSP filtering, where the noise picked up by the connected microphone  30  is reduced through a digital signal processing filter in the application processor  102  before the resulting audio stream is transmitted to other devices  10 . Noise reduction may also be adaptive to environment/noise type—e.g. surf noise, motorbike noise. Noise reduction may also be speed dependent, where the speed of a device  10  is determined through GPS or other means. Noise reduction may also be mechanical, using techniques such as foam padding around the microphone element. 
         [0096]    Echo Reduction: Devices  10  may implement echo cancellation, to stop radio transmission where other devices  10  may be close enough to hear voice directly, but only for those people. This may be implemented by proximity detection, for example, based on RSSI between device  10  radios, or other means. 
         [0097]    Mixing: Devices  10  may mix the voice received from various units, tones, or music from an attached or Bluetooth-paired phone. The volume level of each signal while mixing may be adjusted based on the situation. For example, when the user is listening to music from the attached phone  20  and there is incoming received speech—the music may not be stopped but rather the music may slowly be faded out and the voice signal may be faded in. This may give a preferred user experience as compared to abruptly stopping one input and starting another other. In another scenario, when multiple users are speaking, the volume of each user may be adjusted based on the distance—the volume of the user who is farther away may be lower as compared to the user who is close by, for instance. 
         [0098]    Pairing and Grouping: Push-button pairing between any two devices  10  to link the nodes for communication, whereby a user presses a “link” button on one unit and then presses a “link” button on another unit, and an LED or some other indicator shows when a connection is established between the two devices  10 . The connection persists on power off/on. To add a new device  10  to an existing group, the process is repeated using any member of the group and the new unit to be added. Pairing may also use proximity sensing (such as RSSI) to pair only to other nodes within a pre-set distance range (e.g. &lt;2 m). Pairing may be removed by repeating the procedure between any two previously paired units. Besides push-button, pairing may also be initiated by other means like voice commands, NFC proximity, waving or shaking two devices  10 , LED flashing, or positioning units in a specific manner (like upside down). 
         [0099]      FIG. 7  is a sequence diagram describing a secure group admission process for portable group communication devices of embodiments of the invention. For purposes of illustration, user 1  and user 2  may wish to form a group. User 1  may instruct his device  10  to begin the group formation process, such as by pressing a “link” button on his or her device  10 . As above, this button may be a physical button or a virtual one, such as an icon on a display, a prompt, a voice command, or the like. In response to this button press, device 1  broadcasts periodic group invitation messages to other devices in range. Thus, devices in range, such as device 2  shown in  FIG. 7 , receive one or more invitation messages and, in response, display an indicator of a group invitation to their user. In this case, device 2  may turn on a link indicator, such as a light or LED, notifying user 2  of a group invitation. In the meantime, device 1  continues to broadcast periodic invitations. 
         [0100]    User 2  may ignore the request, which may time out after a predetermined time, or accept. Acceptance may be by pressing an appropriate button on device 2 , responding to a prompt, etc. Upon acceptance, device 2  begins broadcasting periodic invitation response messages to any other device in range, as shown. Upon receiving one or more of these response messages, device 1  turns on its link lamp or other indicator, indicating to user 1  that user 2  has accepted his or her group invitation. Device 1  then broadcasts a join acknowledge message acknowledging to device 2  that it has joined the group. 
         [0101]    Invitations and responses may each be performed according to any accepted protocol, and may each include any information required or consistent with the protocol. For example, messages may include a security key, a unique identifier such as the MAC address of the device sending the message, a random number, or the like. Subsequent packets sent between group devices may include these identifiers, so that receiving devices acknowledge and use packets from other devices in the group, and ignore or reject those with identifiers of devices not in the group. 
         [0102]    In certain embodiments, it may be desirable to range-limit group invitations. More specifically, device 2  may look at the signal strength of the invitation signal, and ignore the invitation if the signal is too weak, i.e. if device 1  is too far away (indicating a likely accidental group invite) or the connection is too unreliable. Likewise, device 1  may examine the signal strength of device 2 &#39;s response message, and decline/ignore it if it is too weak, and device 2  may also examine the strength of device 1 &#39;s acknowledge message. 
         [0000]    Operation in Conjunction with Phones or Other Devices 
         [0103]    As described above with reference to, for example,  FIG. 3 , devices  10  may operate in conjunction with phones  20  or other electronic devices. This allows for added functionality when operating devices  10 . More specifically, various functions of phones  20 , such as music playback, may be made available through devices  10 . In this manner, devices  10  may allow for group communication while also supporting functions of phones  20  such as music. 
         [0104]      FIG. 8  is a sequence diagram describing combined music and speech operation. In  FIG. 8 , user 1  and user 2  communicate with each other via their devices device 1  and device 2 , while device 1  is also connected to phone 1 . Here, user 1  first decides to listen to music, and accordingly instructs his phone 1  to play music or other audio through device 1 . The phone 1  pairs with device 1  in known manner via any wired or wireless communication protocol, such as Bluetooth or via cable connection. Once user 1  selects his or her desired music on phone 1  and presses PLAY, phone 1  transmits the selected music or other audio file to device 1  for playback. 
         [0105]    Embodiments of the invention allow one device in a group to be selected as Leader, with the rest of the devices in the group then being Followers. In this arrangement, if the Leader plays music, this same music is also played to each of the Followers. Thus, device 1  transmits its received music to device 2  as well, and both devices play this music. User 2  thus hears the same music as user 1  selects and hears. 
         [0106]    When user 1  (i.e. the Leader) speaks, device 1  picks up his or her speech, halts music playback, halts transmission of music to device 2  (so that device 2  also halts music playback), converts the received speech to a digital audio signal as above and transmits the audio stream to device 2 . Device 2  then plays the audio stream to user 2 . When user 1 &#39;s speech ends, device 1  stops transmitting audio to device 2 , resumes music playback to user 1 , and also resumes transmission of music to device 2 . Thus, when user 1  stops talking, both device 1  and device 2  resume playing music. 
         [0107]    When user 2  (i.e. the Follower) speaks, device 2  picks up his/her speech, and transmits the resulting audio stream to device 1 . Device 1  then halts music playback to user 1 , halts transmission of music to device 2 , and plays the audio stream instead. When user 2  stops speaking, device 2  ends audio transmission to device 1 . Device 1  then stops audio playback, resumes music playback to user 1 , and also resumes transmission of music to device 2 . Thus, when user 2  stops talking, both device 1  and device 2  resume music play. 
         [0108]    Embodiments of the invention also include further functionality. Exemplary added functionality may be implemented by any one or more of the application processor  102 , audio codec  106 , and DSP  108  in conjunction with a phone  20  or other device, in known manner, and is listed and described as follows. If desired, devices  10  may implement any one or more of the following functions: 
         [0109]    Phone connectivity: Device  10  can connect to a phone over a wired analog or digital connection, or via a wireless connection such as Bluetooth. It may also be paired to a phone  20  over Bluetooth and possibly concurrently paired to Bluetooth headphones. It may also be connected over an analog, digital or Bluetooth connection to an external speaker. 
         [0110]    Phone Call Control: Use cases related to phone interaction are enabled or disabled, depending on whether a device  10  detects that it is connected to a phone. For example, the user may be able to mute phone calls from their device  10  or receive indication of the caller name, phone number, etc. on the device  10 . 
         [0111]    Connected Phone Calls: When a call is received from a connected cellphone, the call is passed through the device  10 , which may accordingly stop its on-board radio transmission. The user may also prefer to give priority to the on-board radio transmission of the device  10  over the phone call or route the phone call to other devices  10 . 
         [0112]    Shared Phone Calls: A device  10  may be configured to enable the sharing (streaming) of a single cellular call among multiple devices  10 . 
         [0113]    Music and Transmitted Voice Control: The device  10  may mix two streams of audio, where the first stream is continuous such as music from a connected phone and the second is intermittent speech received from another device  10 . For example, music volume may be lowered so that the speech can be heard over the music. Music volume may be ramped down as a function of the duration of the conversation or speech. For instance, more speech decreases the ramp speed. Generally, the music stream is played at full volume and when the second stream contains speech, only the second stream is played (or, instead of outright muting, both streams are combined but the volume of the first stream is significantly lowered). After speech ends, the volume of the first stream may be ramped back up as a function of time, at a constant rate, or at a rate determined by the probability that further speech acts will ensue. For example, a sigmoid-like music-adjustment volume curve may be employed as a function of numbers and durations of idle events and speech-detected events, so that more talk=flatter volume curve. Thus, long conversations will be free of bursts of music but isolated speech acts will be followed quickly with a return to full volume music. 
         [0114]    “Tap-on-shoulder” situation: Include functionality to mute music where users are in close proximity (as determined by GPS or perhaps NFC), without transmitting speech (so as to, for example, address the common situation of needing to tap a person on the shoulder to speak with them because they are listening to music). 
         [0115]    Local storage for music files: for listening to music without connected phone or for storing past conversations or videos. Received audio or files may be stored for future local retrieval and playback. 
         [0116]    Voice Recording: Devices  10  may also store conversations. The recorded voice may be time stamped, location stamped or marked in some other way, possibly in connection with another accessory such as a GoPro™ or other video or photo capture device, to later allow synchronized playback of the voice with the video or photos. 
         [0117]    Audio Watermark: The common voice, or an added non-audible watermark track or other syncing method (such as a global clock signal or the like) may also be used as the means to synchronize videos and audio/text captured on a multitude of devices, such as GoPro™ or similar devices, thereby facilitating the recreating of a multi-media, multi-view experience. 
         [0118]    Other Devices: The functionality described here is not limited to control and interoperation with cell phones. Devices  10  may also be connected to other devices such as tablets or notebook computers, as will be understood by one of ordinary skill in the art. 
         [0119]    It should be noted that the present invention can be implemented in software and/or in a combination of software and hardware, e.g., using application specific integrated circuits (ASIC), a general purpose computer or any other hardware equivalents that can implement and carry out any of the modules and processes described above. In one embodiment, the above described functions and processes can be loaded into memory  104  and executed by processor  102  and/or DSP  108  to implement the functions as discussed above. In another embodiment, this functionality may be integrated into another device like a phone or tablet. 
         [0120]    The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. Additionally, different features of the various embodiments of the present invention, disclosed or otherwise, can be mixed and matched or otherwise combined so as to create further embodiments contemplated by the invention.