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QUALITY OF SERVICE FOR WIRELESS TECHNOLOGY IN
THE WIDEXLINK SYSTEM
WidexLink wireless technology enables communication between
two partners of a binaural pair of DREAM hearing aids and with
their matched external devices. The requirements for the quality
of service (QoS) vary among the various components and their
intended user scenarios.
For programming, these requirements include a BER (Bit Error
Rate) better than 10
-3
, at a bitrate of 212 kbits/s, a semi-duplex
transmission with a required acknowledge, a transmission latency
in each direction (2x) and a receive-to-transmit mode (RX to TX)
time. The data are saved in the hearing aid even when transmission
is interrupted.
During daily use, the requirements on audio streaming between
hearing aids include a BER better than 10
-3
. The communication is
simplex with a bitrate of 212 kbits/s. The additional audio decod-
ing in this mode results in a longer latency which is less than 10 ms.
For remote control commands the QoS requirements include a
BER better than 10
-2
. The lower BER requirement results from re-
dundant transmissions. Each key press results in transmissions of
7 data packages of which only one is needed for a successful com-
munication.
For inter-ear communication between hearing aids, a BER better
than 10
-3
is required. The communication is updated every 50 ms
(or 20 Hz). The hearing aids continue to amplify based on the last
saved settings even when the transmission range is exceeded or
when communication is interfered.
