Wireless portable communications trends and challenges

Summary form only given, as follows. Commercial communications systems are rapidly expanding to the RF and millimeter-wave spectrum. The impacts of recent advances in the Ill-V compound semiconductor devices and integrated circuits on modern high speed wireless communications systems will be illustrated in a prototype microwave communication link.

Spectrum sharing is proposed as one of the solutions to help the commercial cellular industry meet the 1000x mobile data challenge they are facing. Most of the valuable spectrum lies below 6 GHz and is currently being occupied by commercial communication and RADAR systems. Commercial communication systems of the future are expected to be based on 3GPP Long Term Evolution (LTE) standards. In this paper, we present an overview of some of the techniques that can be used for enabling efficient co-existence of commercial LTE and RADAR systems. The solutions outlined in this paper do not require any changes to the existing standards nor are they specific to any regional regulatory requirements.

Multi robot systems (MRS) have been an active research area for many years. With the robot systems leaving the laboratory environment, the aspect of wireless communication is getting more important. Especially in multi robot systems wireless communication is crucial, but existing middleware for robot systems does not regard the challenges of wireless communication. Among other aspects the fluctuation of link delay, bandwidth and availability is characteristic for wireless communication. A communication system in a multi robot system must be capable to manage these challenges. Another issue is efficient point to multipoint (multicast) communication. This allows the availability of the same data to multiple recipients without an unnecessary high increase of network load compared to unicast communication schemes.We therefore propose a multicast communication framework for a multi robot system based on wireless communication. The framework is organised in two parts. The first part is a general framework for a wireless multicast communication protocol, which is optimized to offer efficient multicast communication capabilities on wireless networks and takes the available link qualities into account. The second part is a framework for a robot middleware, which benefits from the multicast communication optimizations of the first part. The framework assumes unreliable communication, thus taking fluctuating link qualities into account. Both parts are already implemented on a real system and are used in an experimental multi robot system.

Wireless communication is ubiquitous in people’s daily life. As people’s requirements for wireless communication continue to increase, how to improve system performance has become a core issue that communication researchers pay attention to. Wireless cooperative communication is considered to be a key technology in the future communication system because it can provide better communication quality, higher system capacity, wider communication coverage, richer services, and high spectrum utilization efficiency. The proposed network coding can effectively eliminate the transmission bottleneck problem faced by wireless cooperative communication. The development of audio and video communication coding technology has increased the demand for audio and video communication services. The goal of audio and video coding is shifting from traditional storage applications to network transmission. Therefore, the audio and video coding technology for network transmission is being affected by academia and industry. The purpose of this paper is to study the communication audio and video codec methods in wireless cooperative communication networks and to understand the development status of audio and video codec by reading a large number of related documents. On the basis of the problem, relevant experiments are designed to conduct in-depth research. Experimental results show that this scheme can simplify the implementation of scalable coding, improve the coding efficiency of the enhancement layer, and improve the quality of the reconstructed video when the audio and video streams are truncated.

The demand for portable wireless communications systems was pushed by the expansion of personal and business wireless services. As a result, portable devices tend to become cheaper, smaller and lighter with long lasting batteries. Those tendencies increased the focus on the implementation of RF integrated circuits using CMOS technology, which is continuously under the speed evolution pressure of digital circuits. The high speed of CMOS circuits allows integrated solutions to RF implementations. The implementation of an RF IC is very important since it meets the needs of portable communication systems. This article describes the design of a low noise amplifier (LNA) that is used in RF transceivers, in a 0.35 /spl mu/m CMOS process. The LNA is intended to be used in the receiver of a mobile CDMA station, working in the 824-894 MHz range, evaluated by the TIA/EIA/IS-98-A interim standard.

In this article, a coplanar-waveguide (CPW)-fed dual-band antenna for applications of the multisystem integration has been demonstrated. The resonance analysis of the stepped-impedance (SI) monopole is presented by using the transmission-line analysis method. The frequency-response characteristics of the SI-monopole, such as the resonance condition and harmonic response, are systematically summarized. Furthermore, utilizing several simple techniques, such as bent feeding topology, asymmetric ground plane, and an L-shaped slot etched in the ground plane, a right-hand circularly polarized (RHCP) radiating wave at 1.57 GHz and a left-hand circularly polarized (LHCP) radiating wave at 2.33 GHz are excited for the applications of the global positioning system (GPS) and the satellite digital audio radio (SDAR) service system. After optimization of the geometrical parameters of the proposed antenna, the measured impedance bandwidths of a reflection coefficient less than −10 dB range from 1.40 to 2.98 GHz and from 4.48 to 6.27 GHz, and thus covers most of the commercial wireless communication systems, such as GPS, digital cellular system (DCS), personal communication system (PCS), international mobile telecommunications (IMT)−2000, wireless local area networks (WLAN), and long-term evolution (LTE) 2300/2600. The measured 3-dB axial ratio (AR) bandwidths are about 80 MHz at 1.57 GHz and 100 MHz at 2.33 GHz.

This paper discusses a single-carrier signal with a Modified Root Roll-off (MRR) filter to attain a lower Peak-to-Average Power Ratio (PAPR) than that of the conventional Root Raised Cosine (RRC) filter. A combination of the MRR filter on the transmitter side and the RRC filter on the receiver side satisfies the Nyquist criterion since the total transfer function has a roll-off region expressed in a sum of sinusoidal functions such as A sin(x) and B sin(3x). The coefficients are fixed so that the PAPR of the transmitted signal can be minimized under the constant bandwidth condition given by the roll-off factor. The PAPR reducing effects of the MRR filter are approximately 0.5 dB and 1 dB when the roll-off factors are 0.6 and 1, respectively. The above result shows that the MRR filter is applicable to generating the transmitted signal with a low PAPR in the commercial wireless communication systems where the receiver uses the RRC filter. The MRR filter would be useful to design a system under a strict condition of power amplifiers such as a sub-THz communication system that is one of beyond 5G system candidates.

In the high-speed maglev transportation system, an efficient and reliable train ground communication system plays an important role in ensuring the safe operation of the train. And, the increasing demand for high-speed broadband services such as digital video services also puts forward higher requirements for wireless communication in high-speed transportation. The development of the fifth generation mobile communication (5G) is to meet the requirements of high reliability and super capacity of wireless communication system. However, the explosive growth of data, high-speed and low delay communication requirements have brought great challenges to the communication system. The organic integration of wireless communication and deep learning is expected to solve the technical problems of complex communication systems. Firstly, this paper describes the challenges of the 5G key technology - MIMO technology in channel estimation, beamforming and channel detection. Then it introduces a series of research on introducing deep learning into MIMO physical layer technology. The results show that deep learning is expected to solve the problems of MIMO technology.

Increasingly, smart grid solutions use wireless communications as a core component for moving information and, thus, facilitate more intelligent decision making. This article considers a synchrophasor system implemented on a distribution feeder simultaneously using two separate wireless communication technologies to transmit synchrophasor measurement data. This system was implemented to demonstrate advanced distributed-generation control and how it impacts grid support on the broader electrical feeder. For purposes of performance evaluation, both a wireless serial communications solution and a third-generation (3G) cellular solution were implemented. Phasor measurement unit (PMU ) data, which are streamed without interruption up to 60 messages/s, offer a means to continuously evaluate the two communications systems; performance data measured and archived over a one-week period provided detailed comparison information. Using this information, this article recommends which wireless technology may be better suited for various utility applications.

This paper has presented our interesting in wireless underwater communications for different ocean water types. Recent interest in ocean exploration has brought about a desire for developing wireless communication techniques in this challenging environment. Due to its high attenuation in water, a radio frequency (RF) carrier is not the optimum choice. Acoustic techniques have made tremendous progress in establishing wireless underwater links, but they are ultimately limited in bandwidth. In traditional communication systems, constructing a link budget is often relatively straight forward. In the case of underwater optical systems the variations in the optical properties of ocean water lead to interesting problems when considering the feasibility and reliability of underwater optical links. The main focus of this paper is to construct an underwater link budget which includes the effects of scattering and absorption of realistic ocean water. As well as we have developed the underwater optical wireless communication systems to have shorter ranges, that can provide higher bandwidth (up to several hundred Mbit/s) communications by the assistant of exciting high brightness blue LED sources, and laser diodes suggest that high speed optical links can be viable for short range application. The received signal power, signal to noise ratio, bit error rate, transmitted signal bandwidth, and transmission bit rates are the major interesting parameters for different ocean water mediums as a criteria of the best signal transmission characteristics of short wireless optical communications over wide range of the affecting parameters.

Vehicle-to-vehicle and vehicle-to-infrastructure wireless communications are currently under development to improve traffic efficiency and safety. The time-critical nature of road safety applications imposes the need to accurately dimension the operation and performance of wireless vehicular communication systems. Given that radio propagation modeling has been shown to importantly affect the performance of traditional mobile and wireless communication systems, this work investigates its impact on the dimensioning of traffic safety wireless vehicular communications by separately analyzing the contributions of pathloss, shadowing and fast fading.

Physical layer security (PLS) in wireless communication systems has attracted extensive research attentions in recent years. Unlike cryptography-based methods applied in upper-layer in network, PLS methods are applied in physical layers and can provide information-theoretic security by utilizing the randomness of signals and wireless channels. In this survey, we provide a comprehensive review in the domain of physical layer authentication (PLA) in wireless communication systems, including the concepts, several key techniques of typical PLA architectures as well as future challenges and research trends in more sophisticated communication systems. The survey begins with an overview of the background and basic concepts of PLA, such as the general model of wireless security communication system, typical frameworks of key-based/less PLA systems, and the common attack models. We then discuss the major concerns and key techniques that are applied in PLA systems, where three types of authentication schemes are considered, i.e., the authentication based on channel information, radio-frequency and identity watermarks. Basic models and representative research results about key approaches and techniques applied to the authentication systems above are subsequently covered. Finally, the associated challenges and potential research trends of PLA in future communication systems are presented at the end of the survey paper.

The article deals with the issues of interference and intelligence protection of radio communication means of the mobile component of the tactical command and control link in the conditions of active use of electronic warfare. The problems arising from the use of standard radio communication means that do not provide a sufficient level of protection against intentional interference and interception of signals by the enemy are analysed. The necessity of developing a scientific and methodological apparatus for adapting the radio networks of the National Guard of Ukraine to the conditions of active interference is substantiated. An analysis of modern radio communication equipment used in the military, including portable radios, satellite communication systems, tactical Wi-Fi solutions and software-based radio networks, is carried out. It is determined that the existing communication systems do not provide effective counteraction to enemy radio jammers, especially in direct contact. A new method of spatial interference rejection based on the optimal location and direction of antenna systems of ground-based transmitters and receivers of UHF/VHF and Wi-Fi radio signals is proposed. The proposed method takes into account the tactical situation, the territorial location of radio network nodes and allows to increase the interference immunity of radio channels by changing the characteristics of antenna systems. A mathematical model of interaction between the elements of the radio communication system and active radio masking means is substantiated, which allows determining the optimal parameters of antenna systems and radiation power. The threshold values of the suppression coefficient are determined, at which the required quality of signal reception is guaranteed under the conditions of targeted concentrated interference. The concept of a stable radio communication zone is expanded, in particular, the dependence of its area on the shape of the radiation pattern and the distance between the elements of the communication system is substantiated. For the first time, a comprehensive analysis of the combined effect of intentional interference and active radio jamming on the stability of radio channels is carried out, which allows a reasonable approach to planning radio communications in the conditions of electronic warfare. An algorithm for determining the area of stable exchange for the points of the operational map of combat operations is proposed, which allows to effectively plan the location of communication means and active radio masking means. The practical significance of the obtained results lies in the possibility of applying the developed method in the creation of adaptive radio communication systems that take into account the real tactical situation, which can significantly increase the efficiency of troop management in the conditions of information influence of the enemy.

Radio frequency (RF) MEMS is an emerging sub-area of MEMS technology that is revolutionizing RF and microwave applications. RF MEMS devices have a broad range of optional applications in military and commercial wireless communication, and navigation and sensor systems. This article presents the EM design of different multiport toggle switches. Such a multiport switch can be used in the compact designs of switching matrices, routing networks, or phase shifters. One application range is the creation of electronically steerable antenna arrays, which can be used for radar applications and satellite communication. The miniaturized switches are based on the single pole single throw (SPST) toggle switch and, in addition to their small size, they have an increased RF performance regarding losses and operation bandwidth (DC to 50 GHz). A 3D FDTD field solver has been used for the electromagnetic design of all the switches. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 329–337, 2004.

Many fields of the industrial automation can be already served by wireless technologies. Due to the different requirements regarding the reliability, latency, number of nodes, node density and range to communication systems there is no uniform standard for wireless communication covering all domains of automation. It is to be expected in the future on a strongly increasing number of radio technologies and protocol stacks on different platforms and operating systems. According to this uniform integration interfaces neither exist on the side of the radio technologies nor on that of classical control systems. For relaying between both systems the architecture and the structure of a convergence middleware are presented, which abstracts the technology-specific details and makes a uniform integration interface available for wireless industrial communication systems. Furthermore a system is presented, with which the integration of wireless technology into automation systems can be automated and thus contributes to the decrease of complexity.