Collision Helps: Algebraic Collision Recovery for Wireless Erasure Networks
Current medium access control mechanisms are based on collision avoidance and collided packets are discarded. The recent work on ZigZag decoding departs from this approach by recovering the original packets from multiple collisions. In this paper, the authors present an algebraic representation of collisions which allows them to view each collision as a linear combination of the original packets. The transmitted, colliding packets may themselves be a coded version of the original packets. The authors propose a new ACKnowledgment (ACK) mechanism for collisions based on the idea that if a set of packets collide, the receiver can afford to ACK exactly one of them and still decode all the packets eventually.