What is "VOLTE (HD+)" -I can't list...
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What is "VOLTE (HD+)" -I can't listen anymore
Smartphones have both mobile phones and computers.So, if you look at the specifications, you can't compare with the jargon ...In this corner, we will gently explain such smartphone -related terms.This time is about "VOLTE (HD+)".
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"VOLTE", which started the service in June 2014, is a voice call service that uses a 4G/LTE data communication network.Compared to the method that uses a line exchange network up to that point, there is no need to switch to 3G networks (CS fallback) compared to the system that uses the line exchange network, and the carrier side has the advantage that radio waves can be used efficiently.There is a restriction that 4G/LTE -compatible and supporting VOLTE is needed, and at present there is a restriction that can only be talked about on terminals between the same carrier (other carriers are a conventional call), but the corresponding terminals are increasing steadily.increase.
Two years later, NTT DOCOMO will start providing VoLTE (HD+), which further improves sound quality.Starting with "Galaxy S7 Edge SC-02H" released on May 19, "Xperia X Performance SO-04H" released in mid-June and "AQUOS ZETA SH-04H" released in early June will be available.Like the conventional VOLTE, it can only be used with a terminal corresponding to VOLTE (HD+) and the same carrier 4G/LTE line network.
The difference between VOLTE and VOLTE (HD+) is in the audio data coding program (audio codec).VOLTE adopts "AMR-WB (AMR WIDE BAND)", which has a higher sound than "AMR-NB (Adaptive Multi-Rate Narrow Band)" used for the voice call service of the line exchange method, but VoLTE.(HD+) uses "EVS (Enhanced Voice Service)" that exceeds it.
The frequency band of the voice corresponding to each audio codec is 300Hz to 3 for AMR-NB.4KHz, AMR-WB 50Hz to 7kHz, EVS is 50Hz ~ 14.4kHz.In addition, the sampling frequency that means how detailed the sound is measuring the sound is 8kHz for AMR-NB, 16kHz for AMR-WB, and 32kHz for EVS.As a result, the amount of data will increase, but you will be able to call with sound quality close to a more natural voice.
Whether or not the SIM of MVNO uses the docomo line can be used has not been revealed as of May 12, 2016.Since the EVS has been approved by the standardization organization of mobile communication technology, 3GPP, the service is expected to be introduced in other carriers, but the service start time has not been disclosed at this time.
DOCOMO VOLTE (HD+) sound quality comparison |
