  Recent advances in backscatter open a promising direction for ultra-low power
communication. However, the state-of-art ZigBee backscatter system,
Interscatter, has several drawbacks to deploy. Its backscatter tag and exciting
source, Bluetooth, can hardly decode packets from other ZigBee nodes, which
left Interscatter one-way communication. Besides, it adopts instantaneous phase
change to modulate information, producing obvious sidelobes and interfering
devices working on neighboring channels severely. To address the problems
mentioned above, we introduce Homoscatter, a novel ZigBee backscatter system
that adopts specific ZigBee devices to generate a single tone and leverages
continuous phase change to modulate information, which eliminates spectral
leakage. It also does codeword translation on the packet header of exciting
packets, improving the utilization of ambient signal.
  The prototype of Homoscatter consists of a microchip radio, a backscatter
tag, and a commodity receiver. The evaluations show that the occupied bandwidth
of Homoscatter achieves 3x smaller than Interscatter. When the channel capacity
is 17.5 kbps, the continuous phase change modulation achieves 13 kbps with the
codeword translation on the excitation header. Based on the widely spread IoT
devices, Homoscatter is a practical way to build an efficient connection
between IoT devices.

Signal Processing;Systems and Control;Systems and Control