Enabling Massive Access of IoT by Superposition Bloom Filter and Compressed Sensing

The pilot design and the corresponding receiver algorithm are the key issue to support massive access via grant-free uplink transmission. In this paper, we propose a Superposition Bloom Filter (SBF) pilot design, where an SBF pilot is composed of several sequences. A SBF pilot can be distinguished from another one by different combination of sequences, i.e., the signature of the SBF pilot. The key improvement over previous BF-related work is to consider superposed complex hash-coded information instead of binary one. To guarantee the detection performance under large pilot pool size, we give the rule of constructing pilot pool based on (K;D;ρ)-expander and design a receiver algorithm including correlation-based sequence detection and compressed sensing (CS) based signature recognition, which uses the amplitude and phase information of received sequences. The simulation results show our proposed SBF pilot and corresponding receiver algorithm greatly improve the detection performance in terms of missing detection probability and false alarm probability in frequency-selective channels, compared with previous work.