Compressive Random Access Using Multiple Resource Blocks for MTC

In this paper, we propose a compressive random access scheme using multiple resource blocks (RBs) to support massive connections for machine type communications (MTC) in 5G systems. The main advantage of the proposed scheme over conventional compressive random access schemes is that there can be more devices than preambles as each active device is to randomly choose a preamble for connection to an access point (AP) at the cost of preamble collisions. To mitigate the performance degradation due to preamble collisions, a block of subcarriers is divided into multiple RBs and an active device is to randomly choose an RB and a preamble within the chosen RB. For multiple signal detection, we consider a low- complexity compressive sensing (CS) algorithm. We also demonstrate that using multiple RBs in random access can offer the benefits of reducing the computation time with a multicore processor as well as improving the throughput.