High Data Rate Capability Research Articles

I-OMP: an improved OMP algorithm for channel state identification in an underwater wireless optical communication scenario.

Underwater wireless optical communication (UWOC) has attracted considerable interest owing to its capability of high data rates and low latency. As a crucial component of UWOC, the transmission characteristics of an underwater channel directly impact the system's performance metrics. However, the existing channel models cannot exactly capture the underwater channel states, thus degrading the observability of channel states. This paper proposes a hybrid-field channel model containing both far-field and near-field path components, in which the signal-dependent shot noise (SDSN) is incorporated as well to accurately describe the underwater channel behavior. Then an improved orthogonal matching pursuit (I-OMP) algorithm that estimates the far-field and near-field path components independently with different transform matrices is developed to obtain the underwater channel state. The performance analyses show that I-OMP can improve the estimation accuracy of underwater channels by iteratively minimizing the mean square error (MSE) and utilizing two different transform matrices, demonstrating the advantage of the proposed I-OMP over the existing methods.

78.8 pJ/b, 100 Mb/s Noncoherent IR-UWB Receiver for Multichannel Neurorecording Implants.

In this article, we present a novel approach for designing a low-power, low-area impulse radio ultra-wideband (IR-UWB) noncoherent receiver capable of achieving a data rate of 100 Mbps. Our proposed receiver demonstrates the ability to demodulate ON-OFF keying pulse streams across the entire lower frequency band defined by the Federal Communication Commission for UWB applications. The key components of the proposed receiver include a reconfigurable differential two-stage low-noise amplifier, a fully differential squarer, narrow-band interface rejection filters, and variable gain baseband amplifiers. These circuits work cohesively to ensure efficient signal reception and processing. To validate the performance of the proposed receiver, we implemented the design using TSMC 40-nm CMOS process technology. A short-range communication including a 1.5 cm tissue layer is tested utilizing a typical upconversion UWB transmitter fabricated in the same technology. Remarkably, the proposed receiver achieves a data rate of 100 Mbps with an impressively low energy efficiency of 78.8 pJ/b and occupies an area of 0.705 mm2. The compact size, remarkable energy efficiency, and high data rate capabilities of the proposed receiver meet the stringent requirements of neural recording implants.

R&D of an Innovative OFDM Communication Payload for Small-Size AUV

With its superiorities of low cost, high flexibility and deployment convenience, small-size autonomous underwater vehicles (AUVs) have been extensively applied to perform a variety of undersea missions. While underwater acoustic (UWA) communication provides a practical way to establish a wireless link, it still poses a significant challenge due to the strict limitations of a small-size AUV platform in terms of load capacity, energy supply and cost. Orthogonal frequency division multiplexing (OFDM) has drawn extensive attention due to its high data rate capability and relative robustness to multipath, the performance of which is unfortunately sensitive to the widespread Doppler effect. While efficient Doppler compensation is significantly crucial for UWA OFDM mobile communication, most of the conventional approaches are conducted using software resampling, thus rendering a huge burden on memory and calculation capability as well as a considerable processing delay. In this paper, from the perspective of hardware completion an UWA OFDM communication payload based on STM32F407 processor is designed and implemented to facilitate agile Doppler compensation with low computational overhead. In particular, after estimating Doppler by calculating the time compression or extension of the preamble signal, Doppler compensation is performed by directly adjusting the direct digital frequency synthesizer (DDS)-driven sampling rate of the analog-to-digital converter (ADC). As the Doppler is compensated parallel to the ADC acquisition, processing delay and memory requirement can be avoided. Finally, hardware-in-loop (HIP) simulation is performed to demonstrate the effectiveness and superiority of the proposed system. The results show that the designed system has the potential to achieve an effective communication rate of 3.19 kbps with the admissible implementation overhead. Future work will entail the integration and performance evaluation of the proposed UWA OFDM communication payload on a practical small-size AUV platform.

Statistical model and forecasting of bandwidth requirements on aggregating nodes of FTTX network using Monte Carlo computations for different demographic segments

Telecom service providers are on a relentless task of development and upgradation of their networks to support increasing requirements of internet users. FTTX landline connections serves multiple users connected on a single line hence need more robust and high data rate capabilities. In FTTX network, link capacity allocation for a service node to aggregating node requires statistical study of usage patterns of customers of the service areas. Different service areas have different usage patterns hence their statistical distributions are different. In this article we have acquired a yearlong data of peak hour utilizations from customers of the largest FTTX service provider in Pakistan to develop a statistical model. We developed an empirical distribution of peak hours of the customers mapped on day clock. This distribution has been used in Monte Carlo computation to find maximum data rate requirements on aggregation nodes in comparison to subscribed data rates of all users on a service node. Further a forecasting model has been used to predict the growth in subscriber demands in different demographic segments for coming years. A combination of maximum possible data rate requirement at aggregation node and forecasted subscriber data rates led to develop a forecast of data rate requirement for next five years in different demographic segments.

Compact Substrate Integrated Waveguide Quasi-Endfire Antenna for CubeSat Integration

A planar quasi-endfire surface-wave antenna (SWA) using substrate integrated waveguide (SIW) technology for integration with CubeSats and other small satellites is proposed in this letter. This antenna can be attached to the body of the satellite, resulting in a compact and low-cost design. A quasi-endfire beam pattern is achieved by the radiation of the fundamental TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_0$</tex-math></inline-formula> surface wave mode at the edge of a grounded dielectric slab (GDS). This mode is excited by a leaky SIW T-junction creating a uniform wavefront that propagates through a truncated parallel-plate waveguide (PPW). A matching section based on an array of subwavelength patches is also added at the interface between the PPW and the GDS for reduced reflections and improved antenna radiation performance. The measured prototype demonstrated realized gain values of 13.3 dBi at 18.6 GHz for a competitive structure size of 5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _0$</tex-math></inline-formula> × 4.8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _0$</tex-math></inline-formula> and with a simulated total radiation efficiency of 93.4%, providing high data rate capabilities for downlink communications. This antenna could be suitable for CubeSat or other small satellite commercial missions, for example, Earth and planetary observations or intersatellite links.

PAPR Reduction in OFDM Systems Using Hybrid Zadoff-Chu Transform Precoding and Partial Transmit Sequence

Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation (MCM) scheme that plays a significant role in digital wireless communication. As a result of its high data rate capability and immunity to multipath fading effect, among others, OFDM remains an ideal technology for 5G communication systems and beyond. Unfortunately, a major drawback of this technology is the high peak-to-average power ratio (PAPR). Nevertheless, many techniques for reducing PAPR have been proposed in the past to address this problem. However, all the techniques previously used have limitations such as high computational complexity, data rate loss, high signal distortion, increase in bandwidth, increase in transmit power, and memory requirements. In this paper, a hybrid technique that combines Zadoff-Chu Transform (ZCT) precoding and Partial Transmit Sequence (PTS) for reducing high PAPR in OFDM signals is presented. To reduce the data rate loss and computational complexity in PTS when a large subblock is used, a Zadoff-Chu precoding is applied to OFDM symbols to precode the symbol before applying PTS with a fewer number of subblocks. An OFDM model was developed where ZCT and PTS techniques were implemented. The performance of the hybrid model was analyzed using Power Spectral Density (PSD), Complementary Cumulative Distribution Function (CCDF), and Bit Error Rate (BER). The simulation result indicates that the hybrid ZCT-PTS provides a better result than using either Zadoff-Chu precoding technique or Partial Transmit Sequence technique separately. A PAPR of 4.2 dB and BER of 3dB is achieved for hybrid ZCT-PTS. The hybrid technique provides a better system performance when compared with Conventional OFDM systems.

The efficiency of Li-Fi (light –Fidelity) security and data transmission compared to Wi-Fi

Light-Fidelity (Li-Fi) technology relies directly on visible light communication (VLC) which uses light emitting diodes (LED). The transceiver in this technology has a modification to enable the LED to use light to transmit data. Li-Fi technology is one of the best technologies used in transmitting data for several reasons; the most notable of this is that the transmission of data by this system is limited to the region reached by the light. Consequently, it cannot be leaked outside, and this will not allow hackers and spies to access the data. One of the advantages that Li-Fi technology also the high speed of data transfer provides. The technology relies on the light waves, knowing the frequency of light waves is 10,000 times greater than the frequency of radio waves. In this research, also we will explore several methods by which we can better use Li-Fi including directional lighting, energy efficiency, signal blocking by walls, internal security, high data rate capability, and integrated network capability. Most of the environments, whether the urban environment, the educational environment, the medical environment, the environment of interference of electromagnetic waves, and other environments, become more efficient when replacing the traditional and common communication technologies with Li-fi technology.

Fog and Atmospheric Turbulence in FSO: Models to mitigate

Free space optics (FSO) is an attractive technique and provides reliability in comparison to radio frequency (RF). The FSO provides high data rate capability and has high bandwidth efficiency. The FSO provides various advantages to radio frequency and it is operable at rain also. But as other techniques FSO also has some issues like absorption, scintillation and scattering, which degrades the quality of the signal. There are various models which estimates the losses due to fog and absorption. In this paper we have analysed the kim, kruse and gamma gamma - gamma turbulence modelin terms of atmospheric attenuation or visibility

Design of a Reduced SpaceFibre Interface: An Enabling Technology for Low-Cost Spacecraft High-Speed Data-Handling

SpaceFibre is an upcoming on-board high-speed communication protocol for space applications. It has been developed in collaboration with the European Space Agency to answer the growing data-rate requirement of satellite payloads such as Synthetic Aperture Radars or hyper-spectral imagers. SpaceFibre offers a complete set of features (i.e., Fault Detection, Isolation and Recovery, and Quality of Service) that guarantees robust communication at the price of higher complexity. This article proposes an innovative modified implementation of the SpaceFibre standard: R-SpaceFibre. It has been designed to reduce hardware resources while keeping high data-rate capability and flow control. Attention is given to the trade-off between Data link layer complexity reduction and protocol features. The proposed protocol is particularly suitable in scenarios where very low bit error rate is foreseen and data integrity is not critical, for example in imaging instruments. The main advantage is a reduction of more than 40% of logical resources required per single interface. R-SpaceFibre may be a suitable solution for several applications, such as low earth orbit CubeSats, which have strict requirements in terms of available logic resources, mass, volume and cost, and more relaxed constraints in terms of upset immunity.

Energy Efficiency Based Joint Computation Offloading and Resource Allocation in Multi-Access MEC Systems

With the rapid growth of computation demands from mobile applications, mobile-edge computing (MEC) provides a new method to meet requirement of high data rate and high computation capability. By offloading the latency-critical or computation-intensive tasks to the edge server, mobile devices (MDs) could save energy consumption and extend battery life. However, unlike cloud servers, resource bottlenecks in MEC servers limit the scalability of offloading. Hence, computation offloading and resource allocation need to be optimized. Toward this end, we consider a multi-access MEC servers system in which Orthogonal Frequency-Division Multiplexing Access (OFDMA) is used as the transmission mechanism for uplink. In order to minimize energy consumption of MDs, we propose a joint optimization strategy for computation offloading, subcarrier allocation, and computing resource allocation, which is a mixed integer non-linear programming (MINLP) problem. First, we design a bound improving branch-and-bound (BnB) algorithm to find the global optimal solution. Then, we present a combinational algorithm to obtain the suboptimal solution for practical application. Simulation results reveal that the combinational algorithm performs very closely to the BnB algorithm in energy saving, but it has a better performance in average algorithm time. Furthermore, our proposed solutions outperform other benchmark schemes.

Interference in IM/DD Optical Wireless Communication Networks

The emerging field of optical wireless communications (OWC) offers exceptional promise as a technology for next-generation wireless networks. High data rate capabilities and ultra-dense access point deployment will allow OWC to supplement traditional RF technologies and remove congestion from the crowded RF spectrum. When implementing OWC via intensity modulation with direct detection (IM/DD), peak optical power emission constrains the instantaneous optical power. Average optical power is also constrained by eye safety regulations and illumination requirements of infrared and visible light communication (VLC) systems, respectively. These constraints differ from the conventional electrical power constraint of RF and wireline systems. Accordingly, performance metrics such as signal-to-noise ratio (SNR) and signal-to-interference-plus-noise ratio (SINR) have been redefined in relation to the optical channel constraints in order to provide fair comparison across OWC implementations. In densely deployed networks, interference has a significant effect on system performance. Two key properties simplify the analysis of RF networks: 1) the relationship between electrical power and interference variance is modulation agnostic and 2) many interferers are typically assumed. The former allows SINR to be defined in terms of the channel constraint and the latter allows the aggregate disturbance from interference-plus-noise to be modeled as an additive Gaussian random component. In OWC networks, the optical power constraints relate to interference variance in a modulation specific manner, and the highly directional optical channel creates instances where a small set of interferers dominate the aggregate disturbance. In this work, we first derive bounds on the variance of OWC interference under the constraints of an OWC channel. We then evaluate the accuracy of assuming that interference follows a Gaussian distribution. Finally, we show results of a study in a testbed environment with 15 VLC-enabled LED luminaires in order to empirically evaluate OWC interference characteristics.

Robust predictive filtering schemes for sub‐band CQI feedback compression in 3GPP LTE systems

The third generation partnership project (3GPP) long-term evolution (LTE) cellular system offers high data rate capabilities by leveraging several techniques including link adaptation and frequency selective scheduling. These techniques rely on accurate channel quality indicator (CQI) feedback reports that are sent by the user equipment (UE) to the evolved node B, a process which results in high signalling overhead. In this study, the authors propose a UE-assisted sub-band feedback compression scheme based on a predictive filtering technique to reduce this signalling overhead. Four schemes based on adaptive filters have been designed, implemented and tested in an LTE system level simulator. Simulation results indicate that the proposed compression scheme has shown efficacy with an overall CQI feedback signalling reduction of up to 92.5% whilst maintaining stable sector throughput, when compared with the standard 3GPP CQI feedback mechanism. Although the proposed scheme exhibits low computational and memory complexity, a reduced-complexity scheme achieving an average computational load reduction of up to 35% is also presented.

A High-Efficiency 60-GHz CMOS Transmitter for Short-Range Wireless Communications

This letter presents a high-efficiency 60-GHz CMOS transmitter for short-range wireless communications. The transmitter comprises a voltage-controlled oscillator and a modulator and uses on–off keying (OOK) modulation for a compact and low-power design. A frequency-doubling modulation technique produces a compact and highly efficient modulator with high on–off isolation. Therefore, the transmitter consumes low power and exhibits a high data-rate capability. Implemented in 65-nm CMOS technology, the transmitter consumes 12.2 mW and occupies a core chip area of 0.04 mm2. The transmitter achieves 11.5-Gb/s wireless OOK data transmission over a distance of 2 cm at a bit error rate of less than $10^{-12}$ for $2^{7}- 1$ PRBS. As a result, the proposed transmitter exhibits an energy efficiency of 1.1 pJ/b.

Comparative Analysis of Fast Fourier Transform and Discrete Wavelet Transform Based MIMO-OFDM

The orthogonal frequency division multiplexing (OFDM) is used in mobile wireless communication systems including IEEE 802.16 (WiMAX), Long Term Evolution (LTE), Long Term Evolution Advanced (LTE-A), IEEE802.11x (Wi-Fi), Hiperlan/2, etc due to its high data rate capability, robustness against multi-path fading (particularly when combined with MIMO antenna technology), frequency selective fading, and its ability to leverage on the use of more bandwidth efficiently, without the problem of Inter Symbol Interference (ISI). Discrete Wavelet Transform (DWT) has strong advantages over Discrete Fourier Transform (DFT) which is a major technique in the achievement of the OFDM system. DWT allows time-frequency domain operation with flexibility and provides solutions to the various drawbacks identified in DFT based MIMO-OFDM technology including spectral wastage as a result of the inclusion of cyclic prefix and high Peak to Average Power Ratio (PAPR). This paper provides an overview of the basic principles of DFT and DWT based OFDM. DWT based OFDM in comparison with DFT based OFDM in MIMO-OFDM system was also investigated using MATLAB based simulations. The Authors has proposed a IDWT based OFDM in MIMO-OFDM systems as it outperforms the IDFT based MIMO-OFDM as shown by our simulation result where the Bit Error rate (BER) of DWT using 8QAM and QPSK modulation scheme is lower compared to the BER of DFT. Our results thus showed improved performance with the use of DWT over DFT in the MIMO-OFDM system.

A 67-mW 10.7-Gb/s 60-GHz OOK CMOS Transceiver for Short-Range Wireless Communications

A low-power and high data-rate fully integrated 60-GHz on-off keying (OOK) transceiver for short-range wireless communication is demonstrated. The transceiver consists of a switch, transmitter, and receiver and uses OOK modulation for a compact and low-power design. With a highly efficient Tx, high-speed modulator/demodulator, and wideband characteristic, the transceiver has low-power and high data-rate capability. Implemented in 90-nm CMOS technology, the transmitter and the receiver consume 31 and 36 mW at 10.7 Gb/s and occupy an active footprint of 0.15 and 0.29 mm2, respectively. The transceiver with an on-board Yagi-Uda antenna achieves 10.7-Gb/s wireless OOK data transmission over 10 cm at a bit-error rate of less than 10-12 for 27 -1 pseudorandom binary sequence. As a result, the proposed transceiver achieves energy efficiency of 6.26 pJ/bit.

The Micro-Vertex-Detector for the P̄ANDA experiment

P̄ANDA is a fixed target experiment that will be carried out at the future FAIR facility. P̄ANDA will provide an excellent tool to address fundamental question in the field of hadronic physics, with a physic program that extends from the investigation of QCD (providing insight in the mechanisms of mass generation and confinement) to the test of fundamental symmetries.The Micro-Vertex-Detector located in the innermost part of the central tracking system will be composed by hybrid pixel and double-sided micro-strip silicon detectors. The Micro-Vertex-Detector will play an important role for the P̄ANDA physics goals. The possibility to reconstruct the secondary vertices and the applicability of a precise D meson tagging is essential for the spectroscopy in the open charm sector and the charmonium mass region. To this aim the Micro-Vertex-Detector features a spatial resolution better than 100μm, a time resolution better than 20ns, a limited material budget, and a high data rate capability in a triggerless environment. An overview of the Micro-Vertex-Detector related to the physics goals will be presented.

Cross Layer Design for Efficient Video Streaming over LTE Using Scalable Video Coding

Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) offers high data rate capabilities to mobile users, and network operators are trying to deliver a true mobile broadband experience over LTE networks. Mobile TV and Video on Demand (VoD) are expected to be the main revenue generators in the near future, and efficient video streaming over wireless is the key to achieve this goal. Video services use both unicast and multicast video transmission based on its applications. Enhanced Multimedia Broadcast/Multicast Service (EMBMS) is defined in 3GPP specification to support download delivery and streaming delivery to group users in LTE mobile networks. In 3GPP Release 8 specification, the EMBMS transmission is classified into single-cell transmission and MBSFN (Multicast Broadcast Single Frequency Network) transmission. In this paper, we propose a Scalable Video Coding (SVC) based video streaming scheme with dynamic adaptations and a scheduling scheme based on channel quality for unicast and multicast video transmissions. In our proposed unicast scheme, Channel Quality Indicator (CQI) feedbacks from User Equipment’s (UE) are used for dynamic adaptations and scheduling. Cross layer signaling between Medium Access Control (MAC) and Real Time Transport (RTP) protocols is used to achieve the channel dependent adaptation for unicast in video server. Simulation results for unicast indicate improved video quality for more number of users with reduced bit rate video traffic. Approximately 13% video quality gain is observed for users at the cell edge using this adaptation scheme. We have also proposed a scheduling scheme for multicast over MBSFN networks. This scheme optimizes the radio spectrum allocation by adaptive modulation and coding (AMC) and frequency scheduling based on distribution of users in different channel quality regions. Through simulations we demonstrate that spectrum savings in the order of 72 to 82% is achievable in different user distribution scenarios with our proposed scheme.

Addressing challenges in serial 10 Gb/s multimode fiber enterprise networks

As the number of networked computer devices connected within local area networks increases, the aggregation requirements of the optical fiber backbone within these networks are also increased. This article highlights the challenges - and a possible solution - to migrating data communications networks to higher data rate capability, while in parallel cost effectively supporting the existing fiber infrastructure

Performance of a mixed-traffic CDMA2000 wireless network with scalable streaming video

CDMA2000 1/spl times/, one of the world's first commercial third generation (3G) systems, offers high-speed data services in conjunction with the voice service. This high data rate capability of CDMA2000 1/spl times/ enables delivery of real-time streaming video. To facilitate efficient network planning for wireless multimedia services, it is important to have a solid understanding of the feasibility and impact of delivering streaming video over a CDMA2000 1/spl times/ network in the presence of voice and data traffic. This paper evaluates video streaming throughputs and wireless system capacities for a CDMA2000 1/spl times/ network under mixed traffic conditions (including voice, web-browsing and streaming video traffic) through a multicell multiuser system-level event-driven simulation. We also demonstrate the advantages of incorporating scalability and dynamic rate control (DRC) in wireless video streaming services.

A high-resolution, imaging neutron beam monitor using gas microstrip technology

The development of a new, high-resolution, position-sensitive beam monitor for slow neutrons on the ISIS spallation neutron source is reported. Based on gas microstrip technology developed at RAL for particle physics applications, the monitor delivers high spatial resolution ( σ=0.1 mm) combined with fast timing response, high data rate capability and low gamma sensitivity. A Monte Carlo model which simulates the interaction of a slow neutron with the gas microstrip detector permits the trade-off between spatial resolution and efficiency in the detector to be explored in the context of proposed applications on ISIS.