KR20070032084A - Speakerphone having improved outbound audio quality - Google Patents

Abstract

Provided is a telephone 310 and method for providing external audio when the telephone is operating in speakerphone mode. The first data unit 350 including the first unit type identifier 360 can be received by a telephone. The first unit type identifier may be an indicator of the type of audio data included in the first data unit. For example, the first unit type identifier may indicate whether the audio data is music or non-music audio data. If the first unit type identifier has a first value, for example, a value indicating that the audio data is music data, the unmuted external audio reproduced from the first data unit can be provided, and voice activity detection can be disabled. . In addition, external audio may be muted.

Audio Transducer, Telephone, Speakerphone, Radio Network, Vocoder

Description

Speakerphone with improved external audio quality {SPEAKERPHONE HAVING IMPROVED OUTBOUND AUDIO QUALITY}

The present invention relates generally to telephones and, more particularly, to telephones having the function of speakerphones.

Mobile phones often include a speakerphone mode that allows the user to use the phone in a hand-free configuration without the use of a headset. When the mobile phone is in speakerphone mode, the sensitivity of its input audio transducer is increased. The output level of the phone's output audio transducer also increases. Thus, the user can continue to communicate over the telephone even if the telephone is placed at short distances.

To prevent outbound audio from the phone's output transducer to be fed back to the phone's input transducer and thus to the original audio source, a voice activity detector (VAD) allows the voice pattern to be output by the output audio transducer. Typically used to mute the phone's input audio when it is playing. When no voice pattern is present in the external audio, it is expected that the telephone user is starting a call. Accordingly, the VAD then unmutes the input audio and mutes the external audio.

Since muting and unmuting of external audio depends on whether or not the voice pattern is present in the external audio, the VAD uses the voice pattern and silent (that is included when the caller stops talking and waits for an answer). must be able to distinguish between gaps. To this end, VAD typically uses general statistics on speech patterns such as energy and periodicity. Sometimes external audio includes a music signal, for example when the telephone user is on a call. The music signal is much more complex than the speech pattern, and the VAD typically has difficulty distinguishing the music signal from the speech pattern and the silent intervals. As a result, the VAD intermittently mutes and unmutes external audio, producing external audio with very annoying coarse sound.

The present invention relates to a method and system for providing external audio to a telephone operating in speakerphone mode. More particularly, the music data received by the telephone can be reproduced as external audio without muting and unmuting of intermittent external audio signals known to occur in conventional telephones. In operation, a first data unit comprising the first unit type identifier may be received by a telephone. For example, a modem may be provided to the telephone to receive the first data unit.

The first unit type identifier may be an indicator of the type of audio data included in the first data unit. For example, the first unit type identifier may indicate whether the audio data is music or non-music audio data. If it is determined that the first unit type identifier has a first value, for example the value indicating that the audio data is music data, the unmuted external audio reproduced from the first data unit may be provided, for example, by the data unit controller of the telephone. The data unit controller can also disable voice activity detection of the phone and mute the inbound audio while the external audio is unmuting.

While the external audio is unmuted, the output transducer gain controller may periodically decrease the sound pressure level (SPL) of the external audio from the first level to the second level. The SPL of the external audio can be gradually reduced from the first level to the second level. The data unit controller can unmute the internal audio when the SPL of the external audio is at the second level. After the SPL is reduced, the SPL may gradually increase from the second level to the first level.

Upon receiving a second data unit comprising a second unit type identifier determined to have a second value, eg, a value indicating that the audio data is non-music data, the data unit controller enables voice activity detection. The data unit controller can also mute external audio and unmute the internal audio while the external audio is muted.

Preferred embodiments of the present invention are described below with reference to the accompanying drawings.

1 is a flow chart illustrating improved sound quality of external audio in a telephone operating in speakerphone mode, in accordance with an embodiment of the present invention.

2 shows a flow chart of detecting whether there is internal speech in a telephone, according to one embodiment of the invention.

3 is a block diagram of a communication network useful for understanding the present invention.

4 is a block diagram of a speakerphone processing system, in accordance with an embodiment of the present invention.

The present invention relates to a method and system for providing external audio to a telephone operating in speakerphone mode. More particularly, the music data received by the telephone can be reproduced as external audio without intermittent muting and unmuting of the external audio signal, which is known to occur in conventional telephones. As defined below, external audio is audio that is played by an output audio transducer connected to a telephone. Internal audio is audio detected by an input audio transducer connected to a telephone.

A flowchart illustrating a method 100 for improving external audio sound quality from a telephone operating in speakerphone mode is shown in FIG. Beginning at step 105, the phone can receive a data unit containing audio data. As defined below, the term “data unit” means a unit of data routed between an origin and a destination in a network. For example, if the network is a frame based network such as a wireless communication network, the data unit may be a frame. If the network is a packet switched network such as the Internet, the data unit may be a packet.

Each data unit may include a unit type identifier. The unit type identifier may be used to identify the type of audio data included in the data unit. The unit type identifier may be stored in a data unit header, day unit trailer, or other data unit. In a very simple form, the unit type identifier may be a single bit flag that identifies whether the data unit contains music data. For example, setting the flag to a value of 1 indicates that music data exists in the data unit. In a more complex form, the unit type identifier provides a wider range of audio data categories that can be identified, including a plurality of bits. For example, the unit type identifier may identify whether the audio data included in the data unit represents voice, tone, silence, or other type of audio that can be identified.

Proceeding to step 110, the data unit may be parsed to distinguish the unit type identifier from other data included in the data unit, and the unit type identifier may be evaluated. In a wireless communication system, non-music data is often encoded differently from music data. For example, non-music data is generally encoded using a vocoder. As is known to those skilled in the art, a large number of vocoder algorithms are available. Examples of such algorithms include Global System for Mobile Communication (GSM), adaptive multiband excitation (AMBE), vector-sum excited linear prediction (VSELP), and the like. This algorithm enables high resolution reproduction of non-music data for a given data rate.

Although the vocoder algorithm can work to encode speech and other audio signals well, music signals tend to be too complex to be encoded by the vocoder. Thus, if a vocoder is used to encode a music signal, much of the music data is lost during the encoding process, resulting in a music signal that sounds very distorted. Eventually, the music signal may be, for example, waveform encoded, or musical instrument digital interface (MIDI), MPEG-1 Audio Layer-3 (MP3), Ogg Vorbis, Windows Media Audio (WMA), real audio, or AAC ( It is typically encoded using another audio compression scheme, which is an audio compression algorithm such as Advanced Audio Coding). This scheme is more suitable for encoding non-speech audio signals, but higher data rates are required to achieve audio quality comparable to the quality of speech encoded with the vocoder algorithm.

Accordingly, referring to decision box 115, the decoding scheme used to decode the audio data may be selected based on the value of the unit type identifier. Thus, if the value of the unit type identifier does not correlate with the music data, the audio data included in the data unit may be decoded as non-music data, generating a non-music signal as shown in step 120. Continuing to step 125, voice activity detection logic can be applied to the non-musical signal, such that external audio produced by the phone's output transducer is not required to be fed back to the phone's input transducer, both internally and externally. Mutes and unmutes audio. The implementation of such negative activity detection is known to those skilled in the art.

Referring back to decision box 115, if the unit type identifier is correlated with the music data, in step 130, the audio data included in the data unit may be decoded as music data, generating a music signal. Decoding schemes compatible with the scheme used to encode the audio data can be used. Proceeding to step 135, the internal audio can be muted and the external audio can be unmuted. The internal audio and external audio may be added to another data unit that includes a unit type identifier indicating that the data unit contains non-music data at a time that voice activity detection logic can be applied for muting and unmuting the internal and external audio. Until received. It can be maintained in each of these states.

In particular, it is advantageous to disable the use of voice activity detection logic when the music signal is generated as external audio. In particular, the music signal is reproduced without the undesirable effect of the intermittent muting that typically occurs when voice activity detection is used during processing of the music signal. This can provide a more enjoyable listening experience during speakerphone operation.

In some cases, the first phone may be used in a noisy environment, such as a club playing loud music. Thus, the audio data for external audio generated from the first telephone is encoded as music. Thus, the internal audio on the second telephone in communication with the first telephone is muted according to step 135, even if the telephone users wish to maintain the call. In order to determine whether users attempt a call when this condition exists, it is desirable to periodically detect whether an internal audio signal is present on the second phone, even when the unit type identifier is correlated with the music data and the external audio is unmuted. Do. This process is shown in the flowchart of FIG.

2 shows a method 200 that is periodically unmuted to detect whether an internal audio signal is present. In addition, the SPL of the external audio may be reduced from the first level to the second level to reduce the feedback of the external audio when the internal audio is unmuted. This method 200 may be implemented when the value of the unit type identifier is correlated with the music data.

Beginning at step 205, the SPL of the external audio can be reduced from the first level to the second level. For example, SPL may be reduced by 6 dB. Nevertheless, the present invention is not limited thereto, and any SPL reduction amount may be implemented. In particular, the reduction in the SPL of external audio may be implemented over a specific period to minimize user perception of volume change. For example, the SPL may decrease over a period of about 50 milliseconds to 1 second.

When the SPL of the external audio reaches the second level, the internal audio can be unmuted. The internal audio can then be sampled, for example by VAD, to determine if internal speech is present, as shown in step 210. Proceeding to decision box 215 and step 220, if there is no internal speech, the SPL of the external audio may increase back from the second level to the first level, and the internal audio may be muted again. As before, the SPL change may be implemented over a specific period to minimize user awareness of the change.

In step 225, a time delay may be implemented before steps 205, 210 and 215 are repeated. The time delay may be in the range between about 2 seconds and 15 seconds, for example. Thus, if a user starts a call, only a portion of that speech will be muted. In one implementation, the time delay may be at least twice the period during which the SPL of the external audio is reduced or increased.

Referring back to decision box 215 and step 230, if speech is present in the internal audio, the external audio can be muted and unmuting of the internal audio can be maintained until the internal speech is stopped or a certain amount of time has passed. Proceeding to step 220, the internal audio can be muted again and the SPL of the external audio can be returned to its previous level. The method 200 may continue while the unit type identifier is correlated with the music data.

3 shows an example of a communication network 300 in which the above-described method may be implemented. The communication network 300 may include wired and / or wireless communication links. For example, the communication network 300 may include a mobile wireless communication network, a cellular telephony network, a public switched telephone network (PSTN), a public switched packet network (PSPN), a wide area network (WAN), a local area network (LAN), an intranet, It may be the Internet, or any other communication network suitable for propagating audio data in both directions.

Phone 310 may be provided as a node of communication network 300. Telephone 310 may be any two-way communication device capable of operating in speakerphone mode. For example, telephone 310 may be a mobile telephone, personal digital assistant (PDA), voice over IP (VoIP), or integrated services digital network (ISDN) telephone device, or any other suitable two having interconnection and / or dispatch capabilities. It may be a -way communication device. Phone 310 may include data unit control logic 330. Data control logic 330 can be used to implement the method described above.

In operation, phone 310 may be communicatively linked with phone and / or call processing system 340 via communication network 330. The telephone / call processing system 340 may propagate at least one data unit 350 including audio data to the telephone 310. The data unit 350 may also include a unit type identifier 360 that identifies the type of audio data contained within the data unit 350, as noted. Telephone 310 may include a speakerphone processing system 320 for processing internal and external audio when telephone 310 operates in speakerphone mode. The speakerphone processing system 320 evaluates the unit type identifier 360 and, as described above, a data unit for determining whether to process audio data contained in the data unit 350 as music data or non-music data. The control logic 330 may further include.

An example of one embodiment of a speakerphone processing system 320 is shown in FIG. 4. However, it should be understood that the speakerphone processing system can be implemented using any of a number of system structures, and the invention is not limited in this respect. The speakerphone processing system 320 may include an inner channel path 405 and an outer channel path 410. Internal channel path 405 may include an input transducer 415 and input transducer gain controller 420, such as, for example, a microphone. The internal channel path 405 may also include an echo canceller 425, an encoder 430, a transmit modem 435, and an internal voice activity detector (VAD) 440. Similarly, external channel path 410 may include receive modem 445, decoder 450, and external VAD 455, output transducer gain controller 460, and external transducer 465. Data unit controller 470 and duplexer arbiter 475 may be operatively coupled to both internal channel path 405 and external channel path 410. Similarly, the comfort noise generation and substitution unit 480 may be operatively coupled to both the inner channel path 405 and the outer channel path 410. The comfort noise generation and displacement unit 480 may also be operatively coupled to the duplexer arbiter 475 as shown.

Echo cancellers, encoders, decoders, transmit / receive modems and comfort noise generation and substitution units are all commercially available and implementations are well known to those skilled in the art. The data unit controller 470 may be implemented in hardware, software, firmware, or a combination of hardware, software, and / or firmware. For example, data unit controller 470 may include a processor, such as a CPU, a digital signal processor (DSP), an application specific integrated circuit (ASIC), or any other processor suitable for performing the data unit controller functions disclosed herein. In addition, the data unit controller 470 may include an integrated circuit (IC) including a duplexer arbiter 475, an internal VAD 440, an external VAD 455, a decoder 450, and / or any other telephone circuit components. It can be included within. In addition, software and / or firmware may be provided to a data store (not shown) for execution by the processor. In addition, the data unit controller 470, the duplex arbiter 475, the internal VAD 440, the external VAD 455, and the decoder 450 may form the data unit control logic 330 of FIG. 3.

When operating in speakerphone mode, internal audio 485 may be received by input transducer 415 and transmitted as input audio signal to input transducer gain controller 420, which adjusts the amplitude of the internal audio signal. Can be. The input audio signal can then be sent to the echo canceller, which also receives an external audio signal from the decoder 450 and couples it from the output transducer 465 to the input transducer 415. Removes some of the feedback that exists due to The internal audio signal is then propagated to encoder 430 and encoded into a data unit for transmission by transmission modem 435. Notably, the encoder can include a non-music encoder, such as a vocoder that encodes a non-music audio signal, and a music encoder, such as a waveform encoder, that encodes a music audio signal. Encoder 430 may also encode a unit type identifier into each data unit to identify the type of audio data to be encoded.

In the external channel path 410, the receiving modem 445 may receive an encoded external signal comprising a data unit and transmit the encoded signal to the decoder 450. Decoder 450 may include a non-music decoder such as a vocoder and a music decoder such as a waveform decoder. The decoder 450 may parse the data unit and evaluate the unit type unit type identifier included in the data unit. If the unit type identifier in a particular data unit indicates that the audio data contained in the data unit is non-music data, then the decoder may decode the data accordingly to produce a non-music external audio signal. The non-music external audio signal can be sent to the output transducer gain controller 460 and then to the external transducer 465 to produce the external audio 490.

The decoder may also indicate to the data unit controller 470 that the audio data is non-music. The data unit controller 470 may then instruct the duplex arbiter 475 to enable voice activity detection within the speakerphone processing system 320. The echo canceller 425 can typically eliminate some of the feedback that is present due to external audio 490 coupling from the output transducer 465 to the input transducer 415 only. Is typically used in phones operating in speakerphone mode. Thus, an internal VAD 440, an external VAD 455, and a duplex arbiter 475 are provided to improve feedback control during speakerphone operation.

In operation, the output of echo canceller 425 may be sent to internal VAD 440. The non-music external audio signal from decoder 450 may similarly be sent to external VAD 455, which also communicatively links to internal VAD 440 to allow direct communication between VADs 440, 455. Can be. VADs 440 and 455 may generate speech detection signals that are used to identify speech information, as opposed to background or other types of noise, respectively.

Speech detection signals from each of the inner VAD 440 and the outer VAD 455 may be in communication with the duplex arbiter 475. The duplex arbiter 475 may process the speech detection signal to determine when to mute and unmute the internal audio 485 and the external audio 490. For example, if the internal audio signal detected by the internal VAD 440 is important, while the external audio signal detected by the external VAD 455 is negligible, this means that while the user at the far end of the communication session is silent, Indicates that the user (near end user) is speaking. Accordingly, duplex arbiter 475 activates internal channel path 405 to capture internal audio 485, while deactivating or muting external channel path 410 to mute external audio 490. Deactivation or muting of the external channel path 410 is accomplished by interrupting the circuit path within the external channel path 410 or reducing the gain of the output transducer gain controller 460.

Conversely, if the internal audio signal detected by the internal VAD 440 is negligible, while the external audio signal detected by the external VAD 455 is important, the duplex arbiter 475 mutes the internal audio 485. In order to deactivate or mute the inner channel path 405, the external audio 490 can be unmuted. Deactivation or muting of the inner channel path 405 is accomplished by blocking the circuit path within the inner channel path 405 or reducing the gain of the input transducer gain controller 420. Thus, the speech of the far end user can be heard through the output transducer 465 while minimizing the risk of external audio 490 feedback to that user.

On the other hand, during the time intervals in which the inner VAD 440 and the outer VAD 455 detect important audio signals in their respective channel paths 405 and 410, the duplex arbiter 475 has no channel path active and which channel. Optional criteria may be applied to determine if a path will be deactivated.

If the encoded external signal received by the receiving modem 445 includes a data unit having a unit type identifier indicating that the data unit contains music data, then the decoder 450 may generate a music external audio signal to generate it. The data can thus be decoded. The music external audio signal may also be sent to the output transducer gain controller 460, which is then sent to the output transducer 465 to produce the external audio 490.

Decoder 450 may also indicate to data unit controller 470 that the audio data is music. The data control unit 470 may then instruct the duplex arbiter 475 to disable voice activity detection in the speakerphone processing system 320. In addition, the data control unit 470 can instruct the duplex arbiter 475 to unmute the outer channel path 410 and mute the inner channel path 405. Thus, as noted, the music signal can be reproduced without the choppy sound that typically occurs when voice activity detection is used while processing the music signal.

As mentioned above, it is desirable to unmut the internal audio 485 periodically to detect the presence of an internal audio signal. When this occurs, the output transducer gain controller 460 may reduce the SPL of the external audio 490 from the first level to the second level to reduce the feedback of the external audio when the internal audio is unmuted. . Similarly, output transducer gain controller 460 may also increase the SPL of external audio 490 from the second level to the first level when internal audio 485 is muted again. The output transducer gain controller 460 may implement the SPL change gradually to minimize the user's sense of change.

The present invention can be realized through hardware, software, or a combination of hardware and software. The invention can be implemented in a centralized manner in one system or in a distributed manner in which different elements are spread between several interconnected systems. Any kind of processing apparatus or other apparatus suitable for carrying out the method disclosed herein is also suitable. A typical combination of hardware and software can be a processing device having an application that, when loaded and executed, controls the processing device performing the methods disclosed herein.

The invention may also be embedded in an application program product, which includes all the features that enable implementation of the methods disclosed herein and may perform such methods when loaded into a processing device. Application programs in this context may include any expression in any language, a) conversion to another language, code, or comment; b) Code or comment on a set of instructions intended to be performed by a system having information processing capability, either directly or afterwards, or with one or both of different types of reproduction.

The invention can be embodied in other forms without departing from the spirit or essential attributes thereof. Accordingly, the following claims may be referred to as indicating the scope of the present invention rather than the foregoing specification.

Claims (10)

A method for providing outbound audio in a phone operating in speakerphone mode, Receiving a first data unit comprising a first unit type identifier; In response to determining that the first unit type identifier has a first value, providing unmuted external audio reproduced from the first data unit. The method of claim 1, Selecting the first unit type identifier as an indicator of the type of audio data included in the first data unit. The method of claim 1, Muting the internal audio while the external audio is unmuting. The method of claim 1, Providing the unmuted external audio further comprises disabling voice activity detection within the phone. The method of claim 4, wherein Receiving a second data unit comprising a second unit type identifier; In response to determining that the second unit type identifier has a second value, enabling voice activity detection within the phone. The method of claim 5, Selecting the second unit type identifier as an indicator of the type of audio data included in the second data unit. The method of claim 5, Enabling the voice activity detection further comprises muting the external audio. The method of claim 7, wherein Unmuting the internal audio while the external audio is muted. A phone having a speakerphone operation mode, A modem for receiving a first data unit comprising a first unit type identifier; And a data unit controller for providing unmuted external audio reproduced from the first data unit in response to determining that the first unit type identifier has a first value. The method of claim 9, The data unit controller further mutes internal audio while the external audio is unmuted.

Images