Dex RC-DEX, User Instructions

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24
Quality of Service for Wireless Technology in the WidexLink
System
WidexLink wireless technology enables communication between
two partners of a binaural pair of tinnitus devices and with their
matched external devices. The requirements for the quality of ser-
vice (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 transmis-
sion with a required acknowledge, a transmission latency in each di-
rection (2x) and a receive-to-transmit mode (RX to TX) time. The
data are saved in the tinnitus device even when transmission is inter-
rupted.
During daily use, the requirements on audio streaming between tin-
nitus devices include a BER better than 10
-3
. The communication is
simplex with a bitrate of 212 kbits/s. The additional audio decoding
in this mode results in a longer latency which is less than 10 ms. For
remote control commands the QoS requirements include a BER bet-
ter than 10
-2 . The lower BER requirement results from redundant
transmissions. Each key press results in transmissions of 7 data
packages of which only one is needed for a successful communica-
tion.
For inter-ear communication between tinnitus devices, a BER better
than 10
-3
is required. The communication is updated every 50 ms (or
20 Hz). The tinnitus devices continue to operate based on the last
saved settings even when the transmission range is exceeded or
when communication is interfered.