Enhanced Orthogonal Frequency-Division Multiplexing With Subcarrier Number Modulation

• Published in: IEEE internet of things journal Vol. 6; no. 5; pp. 7907 - 7920
• Main Authors: Dang, Shuping, Ma, Guoqing, Shihada, Basem, Alouini, Mohamed-Slim
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.10.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Codes; Communication channels; Computer simulation; Error performance analysis; Frequency division multiplexing; Indexes; Internet of Things; Modulation; OFDM; Orthogonal Frequency Division Multiplexing; orthogonal frequency-division multiplexing with subcarrier number modulation (OFDM-SNM); outage performance analysis; Phase modulation; Power supplies; Reliability; Reliability aspects; reliability enhancement; Signal to noise ratio; subcarrier assignment; Subcarriers
• ISSN: 2327-4662; 2327-4662
• DOI: 10.1109/JIOT.2019.2914175

A novel modulation scheme termed orthogonal frequency-division multiplexing with subcarrier number modulation (OFDM-SNM) has been proposed and regarded as one of the promising candidate modulation schemes for next generation networks. Although OFDM-SNM is capable of having a higher spectral efficiency (SE) than OFDM with index modulation (OFDM-IM) and plain OFDM under certain conditions, its reliability is relatively inferior to these existing schemes, because the number of active subcarriers varies. In this regard, we propose an enhanced OFDM-SNM scheme in this paper, which utilizes the flexibility of placing subcarriers to harvest a coding gain in the high signal-to-noise ratio (SNR) region. In particular, we stipulate a methodology that optimizes the subcarrier activation pattern (SAP) by subcarrier assignment using instantaneous channel state information (CSI) and therefore the subcarriers with higher channel power gains will be granted the priority to be activated, given the number of subcarriers is fixed. We also analyze the proposed enhanced OFDM-SNM system in terms of outage and error performance. The average outage probability and block error rate (BLER) are derived and approximated in closed-form expressions, which are further verified by numerical results generated by Monte Carlo simulations. The high-reliability nature of the enhanced OFDM-SNM makes it a promising candidate for implementing in the Internet of Things (IoT) with stationary machine-type devices (MTDs), which are subject to slow fading and supported by proper power supply.