Asymptotic Analysis of Spectral Efficiency With Successive Interference Cancellation in Large-Scale Networks

The surge of interest in massive Internet of Things (IoT) is renewing the investigation for effective scalable multiple access techniques. Limitation of the cost of coordination and contention among a large number of nodes calls for grant-free approaches, exploiting physical layer techniques to solve collisions. Successive Interference Cancellation (SIC) is a key building block of multi-packet reception for massive IoT. In this paper we explore the large scale performance of SIC as the number of simultaneous overlapping transmission grows. A general model of a SIC receiver is stated for a shared channel with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> transmitters. The asymptotic number of correctly decoded packets and spectral efficiency performance are characterized exactly as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> → ∞, for a suitably scaled target Signal to Noise plus Interference Ratio (SNIR). The asymptotic analysis is carried out for any probability distribution of the channel gain, assuming that the average received power level is same for all nodes through power control. The impact of this asymptotic result is discussed as well, highlighting the impact of variability of channel gain on spectral efficiency performance.