Orthogonal Frequency Division Multiplexing With Subcarrier Gap Modulation (original) (raw)
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2020
Aiming to reduce the transceiver complexity and power consumption of communication systems dedicated to serving future Internet of Things (IoT) applications, researchers have taken many approaches with varying degrees of success. A promising candidate solution that can reduce complexity significantly and thus also enhance power-saving is the use of non-coherent modulation-based schemes. Utilizing a non-coherent structure rids the system of any dependency on the knowledge of the phase of the transmitted signal during demodulation. However, although most of the available non-coherent techniques in the literature reduce the complexity of the system, they, unfortunately, suffer from a drawback of some sort, especially in reducing the overall spectral efficiency of the system. To address this problem, we propose a new non-coherent modulation scheme called orthogonal frequency division multiplexing with subcarrier power modulation and differential phase-shift keying (OFDM-SPM-DPSK), as an...
2020
A novel modulation technique termed as orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM) has been proposed for achieving spectral-efficient data transmission in wireless communication systems. OFDM-SPM utilizes the power of each subcarrier in an OFDM block as an extra degree of freedom to convey extra information bits besides the bits transmitted by conventional signal modulation. OFDM-SPM has originally been introduced with binary phase shift keying (BPSK) symbol modulation, and was shown to provide great gains and various merits such as doubling the spectral efficiency, reducing transmission power and transmission times by half. Displaying its capabilities as a scheme to be adopted for future wireless communication systems, a question detrimental to the adoption of OFDM-SPM has yet to be answered. This is whether the gains that OFDM-SPM brings persist when paired with higher order modulation schemes, especially two dimensional signal constellat...
Energy and Spectrally Efficient Modulation Scheme for IoT Applications
Due to the Internet of Things (IoT) requirements for a high-density network with low-cost and low-power physical (PHY) layer design, the low-power budget transceiver systems have drawn momentous attention lately owing to their superior performance enhancement in both energy efficiency and hardware complexity reduction. As the power budget of the classical transceivers is envisioned by using inefficient linear power amplifiers (PAs) at the transmitter (TX) side and by applying high-resolution analog to digital converters (ADCs) at the receiver (RX) side, the transceiver architectures with low-cost PHY layer design (i.e., nonlinear PA at the TX and one-bit ADC at the RX) are mandated to cope with the vast IoT applications. Therefore, in this paper, we propose the orthogonal shaping pulses minimum shift keying (OSP-MSK) as a multiple-input multiple-output (MIMO) modulation/demodulation scheme in order to design the low-cost transceiver architectures associated with the IoT devices. The OSP-MSK fulfills a low-power budget by using constant envelope modulation (CEM) techniques at the TX side, and by applying a low-resolution one-bit ADC at the RX side. Furthermore, the OSP-MSK provides a higher spectral efficiency compared to the recently introduced MIMO-CEM with the one-bit ADC. In this context, the orthogonality between the in-phase and quadrature-phase components of the OSP are exploited to increase the number of transmitted bits per symbol (bps) without the need for extra bandwidth. The performance of the proposed scheme is investigated analytically and via Monte Carlo simulations. For the mathematical analysis, we derive closed-form expressions for assessing the average bit error rate (ABER) performance of the OSP-MSK modulation in conjunction with Rayleigh and Nakagami-m fading channels. Moreover, a closed-form expression for evaluating the power spectral density (PSD) of the proposed scheme is obtained as well. The simulation results corroborate the potency of the conducted analysis by revealing a high consistency with the obtained analytical formulas.
A STUDY ON ENHANCING THE OFDM SCHEMES IN WIRELESS COMMUNICATION
IAEME PUBLICATION, 2019
This paper presents enhancing the OFDM schemes in wireless communication techniques for ultra-low power (ULP) devices. The concept of embedded back-channel communication is proposed to enable a variety of new applications by interconnecting heterogeneous ULP devices through existing Orthogonal Frequency Division Multiplexing (OFDM) based Wi-Fi (IEEE 02.11a/g/n/ac) networks. The proposed back-channel communication allows ULP devices to decode messages embedded in Wi-Fi OFDM packets even if these ULP devices are incapable of demodulating OFDM. The proposed back-channel signaling has unique properties that are easily detectable by non-Wi-Fi ULP receivers consuming sub-mW of active power. The proposed scheme eliminates the need for specialized transmitter hardware or dedicated channel resources for embedded back-channel signal transmission. Instead, carefully sequenced data bit streams will generate back-channel messages from already-deployed Wi-Fi infrastructure without any hardware Modification. This paper demonstrates that Wi-Fi OFDM back-channel communication is feasible in various modulation formats such as pulse position modulation (PPM), pulse phase shift keying (PPSK), or frequency shift keying (FSK). Systematic algorithms are unveiled to create back-channel messages in various modulation formats from a WiFi standard compliant Datapath. Comprehensive bit error rate (BER) performance analysis of various Wi-Fi back-channel communication schemes is derived and validated in realistic multi-path frequency selective fading channels. so the most important aspect of this proposed work is latency and energy consumption so ULP is efficiently implemented in order to provide the optimize and efficient OFDM schemes in wireless communication.
Comparative study of selected subcarrier index modulation OFDM schemes
TELKOMNIKA Telecommunication Computing Electronics and Control, 2019
Orthogonal frequency division multiplexing with subcarrier index modulation (SIM-OFDM) is recently proposed to enhance the performance of traditional OFDM. By incorporating the index modulation in OFDM, the data can be sent on the indices of subcarriers as well as the subcarriers themselves reducing the system complexity. In addition, the Peak to Average Power Ratio (PAPR) and Inter Carrier Interference (ICI) can be reduced by switching on /off some OFDM subcarriers in OOK fashion. In this paper, a comparative study of OFDM with SIM_OFDM and Enhanced SIM_OFDM methods in terms of complexity, spectral efficiency and bit error rate over AWGN channel using two power policies is presented. The simulation results showed that at bit error rate of 10-3, SIM_OFDM and ESIM_OFDM achieved gains in Eb/No of 1.1 dB and 2 dB over 4-QAM OFDM respectively under power reallocation policy. However, the results also showed that traditional OFDM has better spectral efficiency compared to both SIM_OFDM and ESIM_OFDM especially at high M-ary orders.