CC2564_15 Datasheet, PDF (21/47 Pages) Texas Instruments – Bluetooth® and Dual-Mode Controller

CC256x
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SWRS121D – JULY 2012 – REVISED JANUARY 2014
This section describes the assisted HFP 1.6 (WBS) and assisted A2DP modes of operation in the
CC2560B and CC2564B devices. These modes of operation minimize host processing and power by
taking advantage of the device coprocessor to perform the voice and audio SBC processing required in
HFP 1.6 (WBS) and A2DP profiles. This section also compares the architecture of the assisted modes
with the common implementation of the HFP 1.6 and A2DP profiles.
The assisted HFP 1.6 (WBS) and assisted A2DP modes of operation comply fully with the HFP 1.6 and
A2DP Bluetooth specifications. For more information on these profiles, see the corresponding Bluetooth
Profile Specification (www.bluetooth.org/en-us/specification/adopted-specifications).
3.5.4.1 Assisted HFP 1.6 (WBS)
The HFP 1.6 Profile Specification adds the requirement for WBS support. The WBS feature allows twice
the voice quality versus legacy voice coding schemes at the same air bandwidth (64 kbps). This feature is
achieved using a voice sampling rate of 16 kHz, a modified subband coding (mSBC) scheme, and a
packet loss concealment (PLC) algorithm. The mSBC scheme is a modified version of the mandatory
audio coding scheme used in the A2DP profile with the parameters listed in Table 3-6.
Parameter
Channel mode
Sampling rate
Allocation method
Subbands
Block length
Bitpool
Table 3-6. mSBC Parameters
Value
Mono
16 kHz
Loudness
8
15
26
The assisted HFP 1.6 mode of operation implements this WBS feature on the embedded coprocessor.
That is, the mSBC voice coding scheme and the PLC algorithm are executed in the coprocessor rather
than in the host, thus minimizing host processing and power. One WBS connection at a time is supported
and WBS and NBS connections cannot be used simultaneously in this mode of operation. Figure 3-16
shows the architecture comparison between the common implementation of the HFP 1.6 profile and the
assisted HFP 1.6 solution.
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