  Backscatter WiFi provides a novel solution to IoT device's energy
consumption. Different from other backscatter WiFi solutions, MOXcatter works
with multiple spatial streams, making it appliable in 802.11n and beyond. In
this paper, we present a method to solve the problem of phase ambiguity in
MOXcatter due to the deviation of packet offset measurement. The experiments
show that by changing the modulation method from BPSK to DBPSK, MOXcatter
achieves up to 10 dB gain in BER. We evaluate its performance and discuss
possible enhancements and applications.
