  In this paper, we design a first of its kind transceiver (PHY layer)
prototype for cloud-based audio-visual (AV) speech enhancement (SE) complying
with high data rate and low latency requirements of future multimodal hearing
assistive technology. The innovative design needs to meet multiple challenging
constraints including up/down link communications, delay of transmission and
signal processing, and real-time AV SE models processing. The transceiver
includes device detection, frame detection, frequency offset estimation, and
channel estimation capabilities. We develop both uplink (hearing aid to the
cloud) and downlink (cloud to hearing aid) frame structures based on the data
rate and latency requirements. Due to the varying nature of uplink information
(audio and lip-reading), the uplink channel supports multiple data rate frame
structure, while the downlink channel has a fixed data rate frame structure. In
addition, we evaluate the latency of different PHY layer blocks of the
transceiver for developed frame structures using LabVIEW NXG. This can be used
with software defined radio (such as Universal Software Radio Peripheral) for
real-time demonstration scenarios.

Audio and Speech Processing;Sound;Signal Processing