High-speed Wireless Data Communications Research Articles

Persistent Homology Approach for Human Presence Detection from 60 GHz OTFS Transmissions.

Orthogonal Time Frequency Space (OTFS) is a new, promising modulation waveform candidate for the next-generation integrated sensing and communication (ISaC) systems, providing environment-awareness capabilities together with high-speed wireless data communications. This paper presents the original results of OTFS-based person monitoring measurements in the 60 GHz millimeter-wave frequency band under realistic conditions, without the assumption of an integer ratio between the actual delays and Doppler shifts of the reflected components and the corresponding resolution of the OTFS grid. As the main contribution of the paper, we propose the use of the persistent homology technique as a method for processing gathered delay-Doppler responses. We highlight the advantages of the persistent homology approach over the standard constant false alarm rate target detector for selected scenarios.

Four Element MIMO Antenna Systems with Decoupling Lines for High-Speed 5G Wireless Data Communication

A low-profile planar multiple-input multiple-output (MIMO) antenna consisting of four elements with isolation improvement is proposed for 5G mm Wave (24–40) GHz applications. Each radiating element of the MIMO antenna comprises of a microstrip-fed tilted spade-shaped radiator with four asymmetrical slots and a partial ground plane. The antenna is optimized to resonate at 35 GHz covering a wide impedance bandwidth from 23.9 to 40.1 GHz. Two cross lines are then loaded between the antenna elements to improve the isolation > − 30 d B . The MIMO structure with the decoupling lines is fabricated and tested. The measured results are in good correlation with the simulated results. Other MIMO performance metrics such as the envelope correlation coefficient (ECC), channel capacity loss (CCL), diversity gain (DG), and total active reflection coefficient (TARC) are examined, and the results are found to be satisfactory for the device to be used for mm-wave 5G MIMO applications. Also, the antenna’s performance metrics such as radiation efficiency, gain, and radiation patterns over the operating band are presented.

Toward an Efficient C-RAN Optical Fronthaul for the Future Networks: A Tutorial on Technologies, Requirements, Challenges, and Solutions

The exponential traffic growth, demand for high speed wireless data communications, as well as incessant deployment of innovative wireless technologies, services, and applications, have put considerable pressure on the mobile network operators (MNOs). Consequently, cellular access network performance in terms of capacity, quality of service, and network coverage needs further considerations. In order to address the challenges, MNOs, as well as equipment vendors, have given significant attention to the small-cell schemes based on cloud radio access network (C-RAN). This is due to its beneficial features in terms of performance optimization, cost-effectiveness, easier infrastructure deployment, and network management. Nevertheless, the C-RAN architecture imposes stringent requirements on the fronthaul link for seamless connectivity. Digital radio over fiber-based common public radio interface (CPRI) is the fundamental means of distributing baseband samples in the C-RAN fronthaul. However, optical links which are based on CPRI have bandwidth and flexibility limitations. Therefore, these limitations might constrain or make them impractical for the next generation mobile systems which are envisaged not only to support carrier aggregation and multi-band but also envisioned to integrate technologies like millimeter-wave (mm-wave) and massive multiple-input multiple-output antennas into the base stations. In this paper, we present comprehensive tutorial on technologies, requirements, architectures, challenges, and proffer potential solutions on means of achieving an efficient C-RAN optical fronthaul for the next-generation network such as the fifth generation network and beyond. A number of viable fronthauling technologies such as mm-wave and wireless fidelity are considered and this paper mainly focuses on optical technologies such as optical fiber and free-space optical. We also present feasible means of reducing the system complexity, cost, bandwidth requirement, and latency in the fronthaul. Furthermore, means of achieving the goal of green communication networks through reduction in the power consumption by the system are considered.

65-nm CMOS 공정을 이용한 V-Band 차동 저잡음 증폭기 설계

In this paper, V-band differential low noise amplifier(LNA) using 65-nm CMOS process for high speed wireless data communication is presented. The LNA is composed of 3-stage common-source differential amplifiers with neutralization of feedback capacitances using MOS capacitors and impedance matching utilizing transformers. The fabricated LNA has a peak gain of 23 dB at 63 GHz and 3 dB bandwidth of 6 GHz. The chip area of LNA is 0.3 mm2 and the LNA consumes 32 mW DC power from 1.2 V supply voltage.

Energy Efficient Programmable MIMO Decoder Accelerator Chip in 65-nm CMOS

This paper presents an energy efficient programmable hardware accelerator that targets multiple-input-multiple-output (MIMO) decoding tasks of orthogonal frequency-division multiplexing (OFDM) systems. The work is motivated by the adoption of MIMO and OFDM by almost all existing and emerging high-speed wireless data communication systems. The accelerator was fabricated in 65-nm CMOS technology and occupies a core area of 2.48 mm 2 . It delivers full programmability across different wireless standards (i.e., WiFi, 3G-long term evolution, and WiMax) as well as different MIMO decoding algorithms (i.e., minimum mean square error, singular value decomposition, and maximum likelihood) with extreme energy efficiency. The energy efficiency of our MIMO accelerator chip was compared against dedicated application specific integrated circuits for 4 × 4 QR decomposition, 4 × 4 singular value decomposition, and 2 × 2 minimum mean square error decoding. Despite the programmable nature of our design, it delivered energy efficiencies that were 18% to 28% better than the dedicated solutions reported in the literature. This paper presents the VLSI implementation of the architecture discussed in [14]-[16]. It discusses the implementation decisions and tradeoffs used to ensure minimum overall energy consumption of the resulting accelerator chip without sacrificing programmability. Given its programmability and extreme energy efficiency, the accelerator is an ideal solution for today's smart phones that implement multiple MIMO-OFDM waveforms on the same platform.

Compact LTCC-based Multilayer Ultrawideband(UWB) Bandpass Filter Composed of Broadside-Coupled E-shaped Electrodes

Ultra-wideband (UWB) wireless communication systems, utilizing a huge frequency range from 3.1 ㎓ to 10.6 ㎓, are one of the key technologies to meet tremendous demands for up-coming high-speed wireless data communications. The hardware of such systems requires to be made very compact and highly functional. In this paper, research history of our planar-type UWB band-pass filters composed of capacitively couped E-shaped electrodes is outlined first. After that, a super-compact multi-layered UWB bandpass filter is newly developed by using the E-shaped electrode architecture. The designed filter, with overall dimensions of 5.0 x 5.0 x 0.95 mm3, has a UWB passband from 3.3 ㎓ to 10.7 ㎓ in simulation (a fractional bandwidth of 106 %) and from 3.5 ㎓ to 10.7 ㎓ in experiment (a fractional bandwidth of 100%). In addition, the filter has attractive transmission zeros just below and above the passband, whose creation mechanism is studied theoretically. Also, useful design procedure is introduced for this filter.

Small-Sized Shaped Beam Base Station Antenna with Superior Intersector Interference Reduction in High Speed Cellular Systems

This paper presents a newly developed small-sized shaped beam base station antenna in order to reduce inter-sector interference for next generation high speed wireless data communication systems. The developed antenna realizes polarization diversity as a single small-sized antenna without decreasing the 3dB main beamwidth compared with the conventional antenna by applying a newly designed beam shaping method. Furthermore, side sub-reflectors are newly installed in the radome to reduce the antenna beam gain in the direction toward the edge region neighboring the other sectors of the horizontal antenna pattern. By adopting this type of reflector, the diameter of the radome can be minimized at 0.65λ, which is slightly longer than that of the conventional antenna. Both a computer simulation and a field measurement test based on an actual cellular network were conducted for the purpose of clarifying the validity of the shaped beam antenna. In the results, the CINR at the service area by the shaped beam antenna was 1dB and 3.5dB better than that of the conventional antenna at the median and 10% of CDF, respectively. The developed antenna will be expected to contribute to the enhancement of the quality of cellular radio systems in the future.

What's Ahread in High-Speed Wireless Data Communications? The Future Will Be Better Tomorrow - And Different Than What We've Been Expecting

The present situation in high-speed wireless data communications is examined. While there is growing demand for wireless bandwidth, the most pressing problem affecting this situation today is the attempt to increase bandwidth by using the same technology with tricks - rather than by using innovation. Opportunities for innovation are quite good with higher carrier frequencies, since these enable simplicity and low power consumption and opening the door to truly portable wireless peer-to-peer (WP2P) networking. Numerous challenges exist in technology and design methods; however, meeting these intellectual challenges is the only route to new and exciting wireless data technologies.

Iterative detection for BLAST systems with an arbitrary number of receive antennas

Turbo-coded Vertical Bell Labs Layered Space-Time Architecture (V-BLAST) is a multiple-antenna system employing turbo codes and bit-interleaving to offer flexible rates and high-speed wireless data communications. The conventional detection techniques based on one-shot demodulation and decoding algorithms may suffer poor performance or simply fail when there are fewer receive antennas than transmit antennas or when the multiple-input-multiple-output (MIMO) channel exhibits strong spatial correlations. We propose employing an iterative demodulation and decoding algorithm that solves these problems and greatly extends the applicability of V-BLAST. Simulations demonstrate that iterative V-BLAST offers the best-known performance in a wide range of settings. Through complexity analysis, we show that (a) the incremental computing complexity is small, although additional memory is required, compared with the conventional one-shot maximum likelihood (ML) decoding method, and (b) an iterative algorithm employing generalized sphere decoding will be a low-complexity, memory-reduced, and high-performance solution. We also give extensions to the technique beyond simple V-BLAST. In addition, when feedback from the receiver to the transmitter is available, we illustrate how to adapt code rate, modulation, and the power distribution to take advantage of the channel knowledge. With a combination of the “best in class” receiver performance and the ability to decode V-BLAST transmissions with fewer receive antennas than transmit antennas, the techniques described here can be viewed as key “technology enablers” for BLAST/MIMO in next-generation systems.

Field trial results for high-speed wireless indoor data communications

This paper reports on the development of a flexible 5-MBd equalized M-QAM testbed for high-speed wireless data communications. The unit operates in real time and was field tested in typical indoor environments. A total of 3600 independent experiments were conducted using the testbed where one of 4-, 16-, 64-QAM constellations were transmitted, and the performance as a function of adaptive equalization and antenna selection diversity was studied. The experimental results presented here help put previous simulation and analytical results into perspective and demonstrate some of the performance bounds associated with a practical implementation. The field trial results show that with only 10-mW of transmit power, reliable 10-Mbit/s data communication can take place in between rooms with a coverage radius of 17 m, and better than 15% outage at an uncoded bit error rate (BER) of 10/sup -3/. The addition of two-branch antenna selection diversity to the system would allow 10-Mbit/s transmission at better than 3% outage and 20-Mbit/s transmission at 10% outage in the same environment. Moreover, 30-Mbit/s data transmission is feasible when both the transmitter and receiver are located within the same room, albeit at higher outage levels. In general, the results demonstrate the tremendous impact that adaptive equalization can have on the achievable performance of indoor links. Average SNR was improved anywhere from 8 dB to 12 dB depending on the particular environment and data rate. The impact on the outage performance, however, was much more dramatic.

A nondirective infrared transceiver for indoor high speed wireless data communication

A prototype of the 1 Mbps nondirective infrared wireless transmission system was designed, and tested. The system design considerations such as the channel property, optoelectronics devices characteristics, and modulation schemes are discussed, and the circuit design and implementation are described. In this system, pulse position modulation (PPM) with short pulse duration and an analog-multiplier type demodulator were used. The feasibility of nondirective transmission is fully demonstrated, showing that it can support successful data communication in a typical room. The system architecture can be upgraded to data rates such as 2 Mbps or higher by only changing the circuit parameters. >

Adaptive equalization for high-speed indoor wireless data communication

The performance of a 4-QAM indoor wireless data communication system with adaptive equalizer is investigated. The effectiveness of using linear and decision-feedback equalizer for Rayleigh and Rician frequency-selective indoor channels is evaluated, and contrasted to the performance of a 4-QAM modem without equalizer. The effects of some important channel and system parameters (multipath spreads up to 200 ns, data rates up to 25 Mbit/s, signaling pulse rolloff factor between 0.5 and 1.0, and additive, white Gaussian noise) on the indoor communication system performance are examined and presented in the paper. The indoor propagation measurements, carried out in a research laboratory, provided data to be used for BER performance assessments of the system with and without equalizer. The performance results based on computer generated channels are then compared with those obtained for measured channel impulse responses.