On the Reception of Concurrent Transmissions in Wireless Sensor Networks
Matthias Wilhelm, Vincent Lenders, Jens Burkhard Schmitt · IEEE Transactions on Wireless Communications · 2014
Numerous studies have shown that concurrent transmissions can help boost wireless network performance despite the possibility of packet collisions. However, while these works provide empirical evidence that concurrent transmissions may be received reliably, existing signal capture models only partially explain the root causes of this phenomenon. We present a comprehensive mathematical model for MSK-modulated signals that makes the reasons explicit and thus provides fundamental insights into the key parameters governing the successful reception of colliding transmissions. A major contribution is the closed-form derivation of the receiver bit decision variable for an arbitrary number of colliding signals and constellations of power ratios, time offsets, and carrier phase offsets. We systematically explore the factors for successful packet delivery under concurrent transmissions across the whole parameter space of the model. We confirm the capture threshold behavior observed in previous studies but also reveal new insights relevant to the design of optimal protocols. We identify capture zones depending not only on the signal power ratio but also on time and phase offsets.