Explore a 15-minute conference talk from USENIX NSDI '22 that introduces Passive DSSS, a novel approach to enhance downlink communication in backscatter systems. Learn how this technique addresses the asymmetry between uplink and downlink transmissions, improving signal-to-interference-plus-noise ratio (SINR) and extending the effective range of downlink communication. Discover the innovative solution to the challenge of DSSS signal demodulation on energy-constrained devices by shifting spreading code generation and synchronization to the gateway side. Examine the experimental results demonstrating a 16.5 dB improvement in downlink SINR and its practical implications for backscatter communication systems.