reZig: Decompose a Collision via Reference Waveform in ZigBee With the proliferation of IoTs, massive deployments of ZigBee devices intensify the collision, a fundamental problem in wireless communication. Conventional solutions exploit the protocol based on CSMA to avoid collision, which incurs considerable overhead. Recently, new solutions which focus on concurrent transmission via collision decomposition are proposed instead of collision avoidance. However, existing approaches to collision decomposition in ZigBee suffer the problems of error propagation and scarcesample error. To make up the weakness of existing solutions, we propose a novel solution, reZig, which leverages the generated reference waveform in the receiver to infer each single waveform in the collision. By inferring the chip independently, reZig is errorpropagationfree. As there are multiple segments provided to decode one chip, reZig can select the segment with most raw samples to ensure the decoding reliability. We implement reZig on the USRP N210 testbed. Experiments demonstrate that reZig achieves the 1.46xe2x88xbc 2.8xc3x97 throughput compared to mZig, the stateoftheart collisiondecomposition approach to ZigBee.

Embedded systems for timexe2x80x93critical applications over WiFi: design and experimental assessment Networked embedded systems for industrial control based on wireless support provide several advantages over wired counterparts, but often reveal unsuitable for the most demanding industrial control applications, such as advanced manufacturing and cooperative robotics. Data exchange over IEEE 802.11 networks may theoretically represent an appropriate solution for timexe2x80x93critical applications, provided that unreliability and nonxe2x80x93 determinism issues are properly handled. In this respect, this paper hence proposes an original solution, based on a crossxe2x80x93 layer approach, to allow the realization of highxe2x80x93speed industrial controlxe2x80x93overxe2x80x93WiFi networked embedded systems. The proposal implements a novel robust framexe2x80x93delay state estimator, a time efficient communication policy, and a specific tuning of critical protocol parameters. Suitable hardwarexe2x80x93inxe2x80x93thexe2x80x93loop experiments have been carried out implemented exploiting two different embedded systems. Preliminary results show that the proposed architecture enables industrial control applications requiring a sampling rate of up to 1 kHz, even in presence of non negligible communication errors.