The Shadowing Phenomenon: implications of receiving during a collision
Alec Woo, Kamin Whitehouse, Fred Jiang, Joseph Polastre, David Culler · 2004
Many wireless networking protocols in use today assume that a connectivity implies interference. While this assumption is usually valid, it does not hold with many radios, possibly including those used in 802.11 and 802.15.4 systems. In systems where a node’s interference range is less than its connectivity, receivers may recover the strongest-power packet in a collision, which we call the shadowing phenomenon. This phenomenon changes the semantics of many collision avoidance schemes such as the use of Acks and RTS/CTS. It also changes network dynamics and connectivity for higher-level protocols such as multihop routing, neighbor selection, and clustering. Techniques can exploit this phenomenon to detect collisions, recover packets, and provide new information to network stacks that can be used to design future protocols.