Error estimating codes for insertion and deletion channels

Abstract

Error estimating codes (EEC) have recently been proposed for measuring the bit error rate (BER) in packets transmitted over wireless links. They however can provide such measurements only when there are no insertion and deletion errors, which could occur in various wireless network environments. In this work, we propose ``idEEC'', the first technique that can do so even in the presence of insertion and deletion errors. We show that idEEC is provable robust under most bit insertion and deletion scenarios, provided insertion/deletion errors occur with much lower probability than bit flipping errors. Our idEEC design can build upon any existing EEC scheme. The basic idea of the idEEC encoding is to divide the packet into a number of segments, each of which is encoded using the underlying EEC scheme. The basic idea of the idEEC decoding is to divide the packet into a few slices in a randomized manner -- each of which may contain several segments -- and then try to identify a slice that has no insertion and deletion errors in it (called a ``clean slice''). Once such a clean slice is found, it is removed from the packet for later processing, and this ``randomized divide and search'' procedure will be iteratively performed on the rest of the packet until no more clean slices can be found. The BER will then be estimated from all the clean slices discovered through all the iterations. A careful analysis of the accuracy guarantees of the idEEC decoding is provided, and the efficacy of idEEC is further validated by simulation experiments.