Wireless communication device and communication terminal

Abstract

A device divides a sampled sound signal into a high frequency signal and a low frequency signal, individually encodes the high frequency signal and the low frequency signal, and generates error detection code pertinent to the high frequency ADPCM data and the low frequency ADPCM data. The device replaces data pertinent to some of a plurality of bits which configure the low frequency ADPCM data with the error detection code and transmits them. A receiver side receives the high frequency ADPCM data and the low frequency ADPCM data, and individually processes the high frequency ADPCM data and the low frequency ADPCM data in accordance with a value of the error detection code.

Description

BACKGROUND[0001]1. Field of the Invention[0002]The present invention relates to a wireless communication device and a communication terminal that perform a communication by use of sound packets.[0003]2. Description of the Related Art[0004]When a user carries a wireless voice communication system in one's hand, such as a cellular phone and a cordless phone, or uses the system at a location where ambient circumstances change, variations occur in received signal strength indicator, a distance between devices, and an interference radio wave, which greatly affects communication quality. A known countermeasure against the problems is; for instance, a technique described in relation to a wireless telephone system as disclosed in JP-T-2002-509387.[0005]The wireless telephone system of JP-T-2002-509387 is made up of a base unit that has a base transceiver and at least one wireless handset and that is connectable with one external phone line. The wireless handset and the base unit implement c...

AI Technical Summary

Benefits of technology

[0010]Moreover, the techniques described in connection with JP-A-2010-154163 and JP-A-7-143074 make it possible to perform audio processing that inhibits muting of a sound or occurrence of unpleasant unusual noise, which would otherwise arise at the time of occurrence of an error, without greatly degrading sound quality even when the communication environments become worse, thereby preventing the listener from feeling unpleasant sensation. In the meantime, these techniques are based on the premise that the system uses a signal band employed in a popular telephone line. However, even in the field of wireless communication, a demand exists for extending a frequency band to a broader band to implement communication of more natural sound quality.

[0011]Accordingly, an object of the present invention is to provide a wireless communication device and a communication terminal that can maintain sound quality without changing a sound data rate through use of a fixed-size packet even when the communication environments become worse and, hence, can enhance accuracy in error detection.

[0017]According to the present invention, in a wireless wideband voice communication, high frequency ADPCM data and low frequency ADPCM data are individually processed by means of an error detection code that is transmitted after replacement of some of bits of the low range ADPCM data. Therefore, even when the communication environments become worse, wideband sound quality can be maintained by a fixed-size packet without changing a data rate of sound.

Problems solved by technology

When a user carries a wireless voice communication system in one's hand, such as a cellular phone and a cordless phone, or uses the system at a location where ambient circumstances change, variations occur in received signal strength indicator, a distance between devices, and an interference radio wave, which greatly affects communication quality.

As a result, when a communication environment becomes worse, sound quality is somewhat distorted, but accuracy in error detection is increased.

For this reason, sound quality is considered to become deteriorated.

However, if the sound quality changes for the worse in sequence as the communication environment becomes worse, the user will experience inconvenience in using the wireless telephone system.

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