Diagnosing Wireless Packet Losses in 802.11: Separating Collision From Weak Signal

It is well known that a packet loss in 802.11 can happen either due to collision or an insufficiently strong signal. However, discerning the exact cause of a packet loss, once it occurs, is known to be quite difficult. This paper takes a fresh look at this problem of wireless packet loss diagnosis for 802.11-based communication and proposes a promising technique called COLLIE. COLLIE performs loss diagnosis by using newly designed metrics that examine error patterns within a physical-layer symbol in order to expose statistical differences between collision and weak signal based losses