Spatially-coupled counter braids

A counter braid (CB) is a novel counter architecture for per-flow measurements on high-speed links. CBs were introduced by Lu et al. in 2007 and they have an asymptotic compression rate (under optimal decoding) matching the entropy lower bound of the flow size distribution. A CB has a layered structure and compresses the flow sizes “on-the-fly” as new packets arrive. In this work, we apply spatial coupling to CBs and show numerically that spatially-coupled CBs (SC-CBs) exhibit improved iterative decoding thresholds. Furthermore, we show that single-layer SC-CBs, which are in fact compressed sensing schemes for nonnegative signals, have a superior undersampling-sparsity phase transition trajectory (under iterative decoding) in the sparse region compared to random Gaussian measurement matrices with ℓ₁-norm minimization reconstruction.