Collision Resolution for Random Access

As a building block toward simple and scalable solution for massive random access, we introduce collision-resolution algorithms using successive interference cancellation (SIC) based on the received signals, with no need any coordination or codebook differentiation. We first consider two-user multiple access ZigZag algorithm. prove that original modified version of it, called double-zipper ZigZag, attain same performance as optimal coordinated time-sharing in high signal to noise ratio (SNR) regime, even presence channel state information (CSI) errors. then extend results case arbitrary number users employing delay-domain processing. Specifically, zero forcing its regularized version, which are able cancel suppress among users, respectively. By obtaining post-processing system model characterizing accumulated during decoupling process, also derive bounds achievable sum-rates proposed algorithm both cases perfect imperfect CSI. Simulation show newly approach have comparable at SNRs.