Compressive Random Access With Coded Sparse Identification Vectors for MTC

In this paper, we study a compressive random access scheme that allows the active device identification with unique sparse identification sequences in machine-type communications to support a number of devices. Since the performance of active device identification can be easily degraded by the background noise as well as distortion by frequency-selective fading channels due to the sparsity of identification sequences, we propose a channel coding approach for sparse identification sequences and derive a low-complexity method for maximum likelihood decoding. Based on the proposed channel coding approach, we can significantly improve the performance of active device identification. We also consider a low-complexity detection method to detect signals transmitted with sparse identification sequences and derive a closed-form expression for the bit error rate.