UWB for Around-the-Body Data Streaming - Ultra-Wideband and 60 GHz Communications for Biomedical Applications - page 46

Fig. 1 Today's solution for
audio streaming/hearing aids
Fig. 2 Integrated solution for
behind-the-ear application
aid devices, are particularly tight. Good audio quality is a prerequisite and mW-
range power consumption is compulsory in view of battery size. The behind-the-ear
device typically serves multiple radio links, e.g., ear-to-ear, ear-to-pocket (a phone
or MP3 player), or even a link between the ear and a remote base-station such as
a TV. The solution exists today in the market is as shown in Fig. 1 . The ear-to-
ear link is supported by a magnetic induction system, which needs a streamer to
communicate between two ears. The advantage of the magnetic induction system
is the low interferences to other users, limited by the coupling distance between
the magnetic devices. The second link, ear-to-pocket, or even the ear-to-remote is
covered by the radiofrequency (RF) system, for example, Bluetooth radio, for its
larger communication distance. The down side of the system for end-users is that
an external streamer is always necessary. From the technical side, two transceivers
are needed which means more power consumption and larger devices. To tackle that
issue, another solution for the behind-the-ear audio streaming is to integrate the two
radios into one. For example, as shown in Fig. 2 , an RF communication system is
chosen to support all the three links.
Apparently, the form factor is reduced in the favor of the end users. However,
challenges arise from the technical side. The GHz communication channel is on
the top of the candidate list rather than sub-GHz system. The main reason is that
the system needs to support a wireless link upto multi-meter range for the ear-to-
remote link. There has been published work regarding path loss in the around-the-
body ultra-wide-band (UWB) channel. In [ 1 ] frequency domain, ear-to-ear channel