Frequency Shift Keying Modulation Scheme Research Articles

Performance evaluation of re-configurable intelligent surface-assisted underwater and free-space wireless optical communication in the skip-zones

Note that 40% of the world’s population, i.e., three billion people, live within 100 km of the ocean or seashore surfaces. To explore and experience marine life, human activities in ocean-based environments are increasing day-by-day. To make human activities safer and stronger, highly efficient and reliable wireless communication is crucial for conveying any unnatural things that occur in oceans. Exploring the vast environment is difficult because of its rapidly changing characteristics, which creates various levels of skip-zone, resulting in the loss of information. A re-configurable intelligent surface (RIS)-assisted optical link is employed to mitigate the effects of skip-zones and enable high-speed and efficient communication links. In addition to this, it is also necessary to convey information to the coastal line through a RIS-assisted free-space optical (FSO) link. In this study, we propose a RIS-assisted dual-hop underwater wireless optical communication (UWOC)-FSO communication system. For the proposed RIS-based dual-hop UWOC-FSO system, closed-form expressions for the outage probability (OP), bit error rate (BER) for coherent and non-coherent type binary phase-shift keying, binary frequency shift keying modulation schemes are derived and results are corroborated with the Monte-Carlo simulations and asymptotic analysis.

On the performance of a hybrid frequency–phase-keying-based MIMO hybrid RF/FSO communication link

A hybrid technique in optical wireless communications is an effective solution to counter impairments and to improve link availability. In this work, a hybrid frequency phase keying (FPK) modulation scheme, based on frequency shift keying (FSK) and phase shift keying (PSK), for a hybrid radio frequency (RF)/free space optical (FSO) communication system is proposed. The hybrid FPK modulation scheme combines advantageous features of FSK and PSK and has the possibility to provide improved link performance in adverse channel conditions. A transmit aperture selection (TAS) and maximal ratio combining (MRC) diversity-based multiple-input–multiple-output (MIMO) hybrid RF/FSO system is considered to mitigate adverse fading effects. Analytical closed-form expressions are derived for the average symbol error probability to trace the performance of the TAS-MRC-based MIMO hybrid RF/FSO system with FPK modulation over fading and pointing error conditions. A comparative analysis of average symbol error performance is presented. The results clearly indicate that the proposed FPK modulation scheme with the MIMO hybrid RF/FSO communication system link is advantageous, as it exploits the complementary properties of both RF and FSO channel characteristics and PSK and FSK modulation schemes. In addition, the proposed MIMO hybrid RF/FSO system with FPK modulation offers superior performance, compared with MIMO RF, FSO, or hybrid RF/FSO systems applied with FSK and PSK modulation schemes. An optimum beam waist is derived analytically, and it is further verified with a numerical optimization technique. All results are validated using Monte Carlo simulation.

Evaluation of Reconfigurable Intelligent Surface-Assisted Underwater Wireless Optical Communication System

Reconfigurable intelligent surfaces (RISs) are an emerging technology aimed to enhance the energy and spectrum efficiency of wireless communication links by reconfiguring the propagation environment of radio-frequency (RF)/optical waves. Planar phased meta-material surfaces or reflect-arrays for RF RIS and multiple smart mirrors have been used for activating optical RIS. In this article, we analyze the underwater optical wireless communication (UWOC) system performance in terms of bit error rate (BER), outage probability (OP) and channel capacity (CC) under the influence of underwater turbulence, beam attenuation, pointing errors and occlusion or blockage due to obstacles. A RIS-assisted UWOC proposed to mitigate the effects obstacles, pointing errors and turbulence and improve the system performances. The probability density function and cumulative distribution functions of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N$</tex-math></inline-formula> RIS elements based UWOC system are evaluated over the underwater turbulence, pointing errors and blockage due to obstacles. The novel closed-form expressions for BER under binary phase shift keying and binary frequency shift keying modulation schemes using with and without coherent detection, OP, and CC for intensity modulation-direct detection and heterodyne detection cases are obtained and plotted according to the number of RIS elements with respect to the average signal-to-noise ratio. The numerical BER results are validated with the Monte-Carlo simulations.

A Wireless Power and Data Transfer IC for Neural Prostheses Using a Single Inductive Link With Frequency-Splitting Characteristic.

This paper presents a frequency-splitting-based wireless power and data transfer IC that simultaneously delivers power and forward data over a single inductive link. For data transmission, frequency-shift keying (FSK) is utilized because the FSK modulation scheme supports continuous wireless power transmission without disruption of the carrier amplitude. Moreover, the link that manifests the frequency-splitting characteristic due to a close distance between coupled coils provides wide bandwidth for data delivery without degrading the quality factors of the coils. It results in large power delivery, high data rate, and high power transfer efficiency. The presented IC fabricated in a 180-nm BCD process simultaneously achieves up-to-115-mW wireless power delivery to the load and 2.5-Mb/s downlink data rate over the single inductive link. The measured overall power efficiency from the DC power supply at the transmitter module to the load at the receiver module reaches 56.7 % at its maximum, and the bit error rate is lower than 10 -6 at 2.5 Mb/s. As a result, the figure of merit (FoM) for data transmission is enhanced by 2 times, and the FoM for power delivery is improved by 38.7 times compared to prior state-of-the-arts using a single inductive link.

On the ASER performance of SC receiver with RQAM and HQAM over [formula omitted]-[formula omitted] fading

In this paper, we consider a multi-branch selection combining receiver over independent and non-identically distributed κ-μ fading channels. We derive new exact expressions for moment generating function of output signal-to-noise-ratio (SNR), average symbol error rate (ASER) of coherent rectangular and hexagonal quadrature amplitude modulations, and ASER of non-coherent frequency shift-keying modulation schemes. Further, an asymptotic ASER expression is also derived to determine the diversity order of the system. The analytical results are validated using Monte-Carlo simulations for a wide range of SNRs and fading parameters. Finally, the impact of channel parameters and the number of branches on the ASER performance is also studied.

Free space optics communication channel with amplitude/frequency shift keying modulation technique based raised cosine line coding

Abstract The objective of the study is to simulate frequency shift keying (FSK)/amplitude shift keying (ASK) modulation schemes with raised cosine line coding based free space optics channel in clear weather conditions. The max. Q and optical signal/noise ratio (OSNR) with FSO channel length variations are simulated for the previous and proposed models at DRs of 10 Gbps, and also the max. Q factor with data rate (DR) variations is demonstrated for the previous and proposed models at 10 km FSO channel length. Max. Q, min. BER, signal power (SP), noise power, and total optical power (TOP) based FSK and ASK modulation schemes are illustrated through APD receiver with FSO channel length of 10 km.

ISM‐band 902‐ to 928‐MHz FSK transceiver with scalable performance for medical devices

SummaryA 902‐ to 928‐MHz industrial, scientific, and medical band transceiver using a wake‐up link for wireless body area networks wearable and implantable medical devices is presented. The design reaches exceptionally low‐power dissipation and provides an adapted data‐rate by gathering the advantages of frequency‐shift‐keying (FSK) and amplitude‐shift‐keying (ASK) modulation techniques. Transmitter (Tx) includes a new efficient FSK modulation scheme to generate up to 20 Mb/s of data‐rate and consumes around 0.084 nJ/b. The integrated receiver (Rx) is based on a new FSK‐to‐ASK conversion technique using on‐off keying fully passive wake‐up circuit (WuRx) with energy harvesting from radio frequency link. The adopted scheme leads to the scalability of energy consumption versus data‐rate at constant transceiver sensitivity, insuring high‐performances requirements. The transceiver is implemented in IBM 0.13‐μm CMOS process. The WuRx achieves a sensitivity of −53 dBm while the main receiver shows −78‐dBm sensitivity. Thanks to the simplified hardware, the receiver consumes only 640 μW while the transmitter uses 1.4 mW from 1.2‐V supply voltage.

EM-Comm

Touch-based communication offers a direct and intuitive way for users to initiate and control data transfer when using tangible and ubiquitous interfaces. However, this requires that each interactive device be instrumented with a dedicated radio transmitter, which limits many applications. While not all devices have radio hardware, all devices do emit small amounts of electromagnetic noise in the form of EMI. We argue that if properly modulated these electromagnetic emissions can be used as an untapped communication channel capable of transmitting arbitrary data. To enable this, a spread spectrum frequency shift keying modulation scheme has been developed to encode data onto the device’s EMI. When the device is touched by a user, the data encoded EMI signal travels through their body and into our custom wrist band, consisting of a single op-amp and MCU. Our results show that we are able to turn electronic primitives such as LEDs, buttons, I/O lines, LCD screens, motors and power supplies into radio transmitters capable of touch communication. Effective data rates range from 5.8Kbps to 22 bit per image depending on the primitive used. To demonstrate this new communication technique, we develop several interactive experiences where users can retrieve complex information such as the function of buttons on a device, directions embedded into a LCD screen, and simplified device pairing. Ultimately, EM-Comm enables nearly any electronic device to be turned into a touch-based radio transmitter with only a software upgrade.

Simple oscillators-based readout circuit for low-power biomedical implant system

This paper reports a wireless sensor readout circuit for continuous physiological parameters monitoring including a potentiostat, a data generation unit and a frequency-shift-keying (FSK) modulator unit with the low drop-out (LDO) regulator for biomedical implant system. The potentiostat can generate an output potential of 0.7 V for the data generation unit. The data generation unit is designed based on a relaxation oscillator scheme and can be used to sense a current signal from any amperometric biomedical sensor and convert the signal to a square waveform in which the frequency of the square wave signal is proportional to the sensor current. FSK modulation scheme has been selected for wireless transmission. Designed with a very simple ring oscillator, this modulator integrates the modulation functionality into the oscillator itself by using the data signal to control the oscillation frequency. The prototype circuits have been fabricated in a 0.35 μm bulk complementary metal-oxide semiconductor (CMOS) process. Working with a regulated 1.8 V supply, the potentiostat consumes only 2 μA of current while the data generation unit can generate around 15.7 kHz output frequency with an input current of 1 μA. The FSK modulator consumes a total current of around 19 μA for a carrier frequency around 1 MHz. An off-chip demodulator is constructed to demodulate the data signal from the FSK modulator and the demodulated signal has less than 1.6 % variation of frequency.

On subsurface wireless data acquisition system

Measurement, evaluation, and monitoring of subsurface objects often require wireless data transmission between an embedded sensor and an exterior host system. Such technologies find applications in many areas-medical imaging, space exploration, earth formation evaluation in oilfield industries, for example. This paper describes a complete wireless data acquisition system that includes design of a transceiver unit, as well as communication protocols for data encoding and decoding. Although the application considered in this paper pertains to the oilfield industry, the method is applicable to other areas as well. The transceiver design is highly constrained due to requirements on physical size, mechanical stability, and low-power consumption. The host antenna generally consists of ferrite-backed coils wound on a metallic cylinder. A critical requirement in the design of these coils is to produce a desired spatial variation of the magnetic field in a specified region. A genetic algorithm is used to optimize the location and excitation of each coil. A combination of finite-element method and superposition principle is used to speed up the solution of forward problem. The data measured by an embedded sensor are encoded with seven-bit cyclic redundancy code concatenated with Manchester code for error detection/correction and bit synchronization. Coded data are finally transmitted by binary frequency-shift keying modulation scheme. Numerical and experimental results for magnetic field, signal-to-noise ratio, and data demodulation are presented.