Cross-Layer Design of Random On-Off Accumulative Transmission with Iterative Detections

Random on-off accumulative transmission (R-OOAT) is a cross-layer technique that can achieve collision-tolerance in the media access control (MAC) layer by leveraging on the signal processing capability in the physical (PHY) layer. In this paper, a new PHY/MAC cross-layer design is proposed for the R-OOAT framework. In the PHY layer, we propose an iterative method for the detection of R-OOAT signals colliding at the receiver, such that the transmitted information can be recovered with a low complexity in the presence of severe signal collisions. The iterative detection is enabled by the unique signal structure of the R-OOAT, and it can operate in both coded and uncoded systems. In the MAC layer, the R-OOAT scheme uses silence periods inside a frame to achieve collision-tolerance, which is different from most conventional MAC schemes that rely on random intervals between frames to reduce collision. The theoretical spectral efficiency of R-OOAT is analyzed with the PHY/MAC operations. Analytical and simulation results show that the proposed cross-layer design can support more users and achieve a much higher spectral efficiency compared to conventional MAC schemes.