Value-Driven XR Transmission in Multi-Connectivity Assisted Communication System

Increasing data transmission rates and bandwidth both belong to the challenges of the development of high-performance wireless communication systems. Multi-channel communication systems commonly use several narrowband power amplifiers each one for a single communication channel. Lossy couplers are needed both to separate the different channels from each other at the amplifiers input and to combine the amplified signals on each channel at the output. This approach depicts a poor efficiency and is limited to a few number of channels since each channel duplication involves 3 dB losses due to couplers. Alternatively, broadband radio frequency power amplifiers ensuring the simultaneous transmission of several carriers on a wide frequency range contribute to increase the cost and resource efficiency of transceivers in wireless communication systems. Gain flatness, a high output power, and low power levels of second and third order harmonics are required on the whole operating frequency range of the power amplifier in multi-carrier communication systems since overtones will degrade the quality of the communication. The present work investigates the performances of a broadband push-pull power amplifier based on LDMOS transistors, the input matching network using a 8:1 transmission line transformer. For the first time investigations on harmonic distortions of the amplified signal when using a transformer with 8:1 impedance transformation ratio are presented. Characterisation of the power amplifiers performances is focused on gain flatness, output power, harmonic distortions and efficiency at 110 W.

Summary form only given. Nanoscale metal-semiconductor-metal (MSM) photodetectors and MESFETs are key elements in ultra-fast optical and wireless communication systems. However, devices with sub-0.25 /spl mu/m feature sizes are typically fabricated using electron-beam lithography (EEL), which has high cost and low throughput. Nanoimprint lithography (NIL), on the other hand, has both low cost and high throughput, as well as sub-l0 nm resolution. We report the fabrication of MSM photodetectors on semi-insulating (SI) GaAs using NIL, and the examination of NIL on the quality of the nanoscale Schottky contact. We found that if the imprint pressure is 600 psi or lower, nanoscale GaAs MSM photodetectors fabricated using NIL are comparable to those fabricated by conventional EEL and photolithography, indicating no degradation to the photodetector Schottky contact induced by the imprint process.

In wireless communication systems, the spatial multiplexing mode of Multiple Input Multiple Output (MIMO) is known to provide significant gain in spectral efficiency in the high Signal to Noise Ratio (SNR) region. Between the two methods, Singular Value Decomposition (SVD) and Bell labs Layered Space Time (BLAST), for implementing spatial multiplexing, the SVD scheme provides much higher spectral efficiency but it is much more complex to implement than the BLAST scheme. The aim of this work is to present an algorithm for antenna selection, which works together with BLAST method and compare the performance with that of SVD method. The comparison is done considering linear receiver architecture, and that the receiver has noisy channel estimates. The channel model used for performance evaluation is as per International Telecommunication Union (ITU)-specifications. It is shown in this work that, the proposed algorithm used with BLAST is very simple to implement and performs at par with SVD.

GSO is an orbit which is approximately 35.786 km from the earth's surface which is strategic for the placement of satellites. Creating justice in the GSO, the International Telecommunication Union (ITU) ensures the availability of a number of slots for equatorial countries. In 2002 the phenomenon of privatization and foreign direct investment has changed the share ownership structure in Indonesia. The telecommunications sector was also affected where the Government of Indonesia now only owns 14.29% of PT. Indosat Tbk. (“Indosat”). Qatar Telcom via Ooredo Asia Pte. Ltd. become the majority shareholder of Indosat (65%); while the rest (20.71%) is owned by the public. This article aims to analyze the urgency of the satellite placed in the GSO and propose analyze the impact of privatization of Indosat in space law perspective. The research method used is normative juridical, with secondary data sources. Qualitative analysis with deductive conclusions. Based on the results of the research, it is known that GSO is a limited natural resource which is regulated in article 33 paragraph (2) in the 1973 ITU Convention, the 1994 ITU Constitution and also in the Radio Regulation. In Article 19 paragraph (11 point a) and Article 44 of the Constitution of the ITU which are limited in nature so that they must be used efficiently, rationally and economically, the Papers Satellites proposed by countries will actually be able to reduce the optimization in utilization and are very strategic for placing satellites in the GSO. There are two legal impacts of privatization of Indosat, first Indonesia has lost a slot in GSO. Second, according to the Liability Convention 1972 and Registration Convention 1972, Indonesia has responsibility for a damage caused by the satellite because Indonesia is the registering State. As a solution The Indonesian government can make a policy that requires the origin country where the Indosat shareholder company to take responsibility.

This paper presents challenges and design perspectives for terahertz (THz) integrated circuits and systems. THz means different things to different people. From International Telecommunication Union (ITU) perspective, THz radiation primarily means frequency range from 300 – 3000 GHz. However, recently, a more expansive definition of THz has emerged that covers frequencies from 100 GHz to 10 THz, which includes sub-THz (100 – 300 GHz), ITU-defined THz frequencies. This definition is now commonly used by communication theorists, and since this paper is intended for people with a wide variety of expertise in system and circuit design, we have adopted the latter definition. The paper brings to the open unmitigated shortcomings of conventional transceiver architectures for multi gigabit-per-second wireless applications, unfolds challenges in designing THz transceivers, and provides pathways to address these impediments. Furthermore, it goes through design challenges and candidate solutions for key circuit blocks of a transceiver including front-end amplifiers, local oscillator (LO) circuit and LO distribution network, and antennas intended for frequencies above 100 GHz.

Harmful interference is an inherent problem for radio communication systems simply because radio waves propagate through space. The International Telecommunication Union (ITU) has played a crucial role in controlling the problems of harmful interference across borders. In this chapter, the various mechanisms put in place by the ITU to prevent and resolve harmful interference are explained and their effectiveness and limitation are discussed.

As the demand for higher data throughput continues to grow, next-generation wireless communication systems are expected to deliver per-link data rates in the range of tens to hundreds of gigabits per second. Photon-assisted generation of terahertz (THz) signals can support larger modulation bandwidths in future ultrahigh-speed wireless communication systems. Orthogonal frequency-division multiplexing (OFDM) has emerged as a promising candidate for future THz communication systems owing to its capability to combat frequency-selective fading and suppress inter-symbol interference (ISI). The least-squares (LS) method is widely used for channel estimation due to its simplicity and low computational complexity. However, it is highly sensitive to noise and interference, resulting in limited estimation accuracy. In this work, we proposed an LS maximum ratio combining (MRC) scheme that combines the SNRs of I- and Q-branch pilot-based channel estimations using the MRC technique to enhance the accuracy of channel estimation and equalization. We experimentally demonstrate 16-GBaud QPSK wireless transmission over 4.6 km at 137.5 GHz using a photon-assisted terahertz IQ-mixer communication system. By employing LS-MRC, we achieve more than 2 dB gain, significantly improving link performance. To the best of our knowledge, this is the first experimental demonstration of high-gain performance achieved through the use of I/Q mixer and LS-MRC techniques in a D-band terahertz communication system.

Circulating tumor cells (CTCs) are cancer cells shed from primary tumor and circulating in the peripheral blood. CTCs initiate secondary tumor colonies and result in more than 90% of cancer death. Isolation and enumeration of CTCs have exhibited promising clinical applications in cancer early diagnosis, prognosis and personalized therapy. However, owing to the extremely low rarity (as low as one CTC in one billion blood cells), CTCs isolation remains a great technical challenge. Current CTCs isolation approaches are based either on their biological properties, including immunoassay, magnetic-activated cell sorting, fluorescence-activated cell sorting, or physical properties, including filtering, inertial microfluidics, deterministic lateral displacement and etc. In general, biology-based techniques are characterized as high purity but low throughput; while physical property based techniques have advantages of low cost and high throughput. In this work, we reported the fabrication of a multilayer crossflow device and demonstrated the capability of isolating CTCs from whole blood based on lateral-flow filtration. The device was consisted of a filter membrane sandwiched between two microfluidic channel layers and fabricated with standard PDMS soft lithography and multilayer bonding technique. A 77.3% filtration efficiency with 4.5um polystyrene beads and a 97% cancer cells recovery rate have been achieved for a single-pass filtration. To further enhance the enrichment ratio(concentration of CTCs prior to filtration over that post-filtration) of CTCs over blood cells, a recirculating filtration system was built by combing the crossflow device with pressure pump and electromagnetic valves. In this system, 1 ml blood sample was treated for 10 times within 40 minutes, with an enrichment ratio of more than 104.

This article examines the role of the International Telecommunications Union (ITU), a specialized agency of the United Nations, in the international effort to manage the radio spectrum. The management of the radio spectrum has been one of the most important activities of the ITU. International agreements for the use of the radio spectrum have been necessary because radio waves do not simply stop at national borders. Governments have viewed the spectrum as an international common resource.Specifically, this article focuses on the development of radio spectrum policy for one of the most significant new radio “services” of the twentieth century: radio transmissions involving outer space. Crucial ITU administrative radio conferences in 1959 and 1963 organized especially by the United States laid the foundation for the Cold War space race. A focus on the efforts by the United States to manage the meetings is particularly important for gaining a deeper understanding of Cold War diplomacy and international relations during this crucial period. In the context of total cold war, diplomacy was closely linked to a broad range of national security concerns, not only military preparedness but also the symbolic and material struggle over hearts and minds. A central concern of the early efforts to arrive at international agreements for space frequencies was satellite communications. The United States was particularly concerned about convincing the international community to set aside large blocks of frequencies for a planned global satellite communications system that would serve multiple national security objectives. The global satellite system would, in turn, play an important role in convincing other countries to agree to set aside frequencies for all forms of space communication.

High-throughput extraction and separation of Ce(III) and Pr(III) using a chaotic advection microextractor

The benefits of 5G millimetre wave (mmWave) technology include high data throughput, very low latency, stable connectivity, and massive capacity. Furthermore, unmanned aerial vehicles (UAVs) are being used as flying base stations to provide a viable option for reliable and cost-effective wireless communication. The goal of this research is to integrate a UAVassisted wireless network with a 5G mmWave communication system and assess coverage performance. The signal between the UAV and the user is heavily distorted by tropical atmospheric parameters such as rain, trees, and fog. This paper investigated the effect of attenuation on user coverage performance in the mmWave frequency bands of 28 GHz and 60 GHz (recommended by the International Telecommunication Union (ITU) for use in 5G cellular services). First, various factors such as rain rate, frequency, and foliage depth are used to calculate the attenuation of rain and foliage. Next, the suggested system model is used to analyse the likelihood of ground users’ downlink coverage in terms of total attenuation, channel gain, channel noise, and interference. However, the impacts of rain and foliage attenuation in various tropical locales cannot be avoided, even given the small cell size of the system.

The 18.6–18.8 GHz band is utilized extensively for scientific uses. Passive microwave measurements in this frequency range are critical for weather forecasting and studies of climate and environmental impacts. This band, however, is shared with commercial communication systems that operate under the Fixed Satellite Service (FSS). FSS communication is used mostly for satellite TV broadcasting, and by a small number of Very Small Aperture Terminal (VSAT) systems. The Radio Regulations of the International Telecommunication Union (ITU) limit the level of FSS transmitted powers in order to avoid interference to passive sensors that operate under the Earth Exploration Satellite Service (EESS). However, Radio Frequency Interference (RFI) affecting spaceborne microwave radiometers such as WindSat, AMSR2 and GPM-GMI at 18 GHZ has been observed and documented for several years since 2010. Calculations considering sea surface reflection show that the observed RFI is consistent with or higher than what could be expected even from the limited level of transmitted power from the FSS. The IEEE Geoscience and Remote Sensing Society (GRSS) has brought this problem to the attention of the ITU Radiocommunication Sector (ITU-R) Study Groups, in view of impending decisions that could potentially dramatically increase the use of this band by commercial operators. The contributions by IEEE GRSS to ITU-R will be presented and various issues involved will be discussed.

WAIC (Wireless Avionics Intra Communications) is a wireless communication system connecting the avionics in the aircraft. This system is currently researched by AVSI (Aerospace Vehicle Systems Institute), ICAO (International Civil Aviation Organization), and ITU (International Telecommunication Union) to substitute cable redundancy in the avionics system. Current stage of the development is to determine the bandwidth for WAIC. The frequency band 4200 - 4400 MHz is the most recommended band for the WAIC system. This paper investigates and analyzes the compatibility of the WAIC system to radio altimeter at 4200 - 4400 MHz. The compatibility simulation is represented by the interference of WAIC to radio altimeter receiver. The four parameters of radio receiver are used in this simulation namely front end overload, receiver desensitization, false altitude report, and power spectral density. The scenario used in this simulation consists of two conditions that are LI (Low Inside) and HI (High Inside). Those conditions are applied to the aircraft that is in the landing phase. The results of the compatibility present that the interference of the WAIC system is not harmful to the radio altimeter. As a result, the frequency 4200 - 4400 MHz is suitable for WAIC.

The input data pipeline is an essential component of each machine learning (ML) training job. It is responsible for reading massive amounts of training data, processing batches of samples using complex transformations, and loading them onto training nodes at low latency and high throughput. Performant input data systems are becoming increasingly critical due to skyrocketing data volumes and training throughput demands. Unfortunately, current input data systems cannot fully leverage key performance optimizations, resulting in hugely inefficient infrastructures that require significant resources - or worse - underutilize expensive accelerators. To address these demands, we present cedar , an optimized and unified programming framework for ML input data pipelines. cedar allows users to define a training job's data pipeline using composable operators that support arbitrary ML frameworks and libraries. cedar 's extensible optimizer systematically combines and applies performance optimizations to the pipeline. cedar then orchestrates pipeline processing across configurable local and distributed compute resources to efficiently meet the training job's data throughput demands. Across eight pipelines, cedar improves performance by up to 1.87× to 10.65× compared to state-of-the-art input data systems.

General wireless network services such as multimedia streaming services require effective models to cost efficiently or fairly distribute limited resources to users in different network environments. The network manager should make decisions related to effective utilization and fair allocation of limited resources, and appropriate guarantee of service quality. In this paper, we introduce a comparative method to help the network manager using resource allocation and pricing mechanisms for wireless multimedia services by considering user qualities of service and service provider profits. To that end, two well-known models of game theory: auction and bargaining are adapted. In particular, progressive second price auction and Kalai- Smorodinsky bargaining solution are analyzed with regard to user cost and utility and service provider profit. While the network manager utilize the result of comparisons, it may be possible to make rational decision of selecting resource allocation and pricing mechanism by considering the status of network.