Mechanisms of immunization of broadband radio stations for targeted interference

Public protection and disaster relief (PPDR) agencies rely on wireless communications to respond in the event of emergencies. Public safety networks (PSNs) provide the wireless network used by emergency services. PSN is used to support push-to-talk services with some data transmission by employing land mobile radios. However, PPDR agencies are increasingly relying on additional information such as videos that require higher bandwidths. Therefore, many countries are transitioning or integrating their public safety networks with advanced broadband wireless communication systems such as fourth-generation (4G) long-term evolution (LTE) and planning to evolve to fifth-generation (5G) new radio (NR) in the future. The paper investigates infrastructure sharing mechanisms and deployment strategies in the transition of PSNs to a 4G LTE network, including a roadmap for cost analysis. Additionally, the paper examines LTE-based PSN deployment scenarios in various countries and engages in a discussion of the advantages and disadvantages of different sharing mechanisms and coexistence schemes. Finally, the challenges within the Public Safety Broadband Network (PSBN) are addressed and potential future research directions in this domain are deliberated.

Coverage study for broadband wireless systems using link adaptation and diversity combining techniques

Multiple Input Multiple Output (MIMO) communication technology has received recently significant attention triggered by the rapid development of Orthogonal Frequency Division Multiplexing (OFDM) broad-band wireless and high speed wireline communication systems. Such systems are very sensitive to Narrowband Interferences (NBI) due to their relatively low transmission power. This type of signal interference can be found in the new unlicensed frequency bands, e.g., the Industrial Scientific Medical (ISM) band, coming from systems such as Bluetooth or microwave ovens which interfere with OFDM based Wireless Local Area Networks (WLAN), like Hiperlan II. Other examples of NBI, typical for Digital Subscriber Line (DSL) communications, are strong Radio Frequency Interferences (RFI) from short-wave radio, Citizen's Band (CB) radio and amateur “ham” radio which interfere with Hybrid Fiber Coaxial (HFC) networks and high speed DSL. Ineffective shielding of a cable network may also cause the ingress from external home electrical devices, such as cordless phones, TVs and computers. Let’s consider a strong NBI signal which resides within the same frequency band as a wideband OFDM signal. In this case, severe Signal to Noise Ratio (SNR) degradation is likely to occur across all OFDM subcarriers due to spectral leakage of the NBI signal from block processing in the OFDM receiver. In Fig. 1, the magnitude-squared of the received

Military applications for heterostructure microelectronics technology

Abstract The fundamental features of next generation wireless communications systems include very high-speed data transmission–reception scheme and ubiquitous interactive multimedia services both of which demand wide bandwidth system. To fulfill this demand, broadband communication system has been brought into the wireless domain, and in recent years, it has been offering a remarkable growth in the telecommunications industry. The major goal of all these technologies is to deliver very high data rate (in multimegabits per seconds) throughput to the end user by satisfying some stringent quality of service (QoS) to support variety of services, such as data, voice, and multimedia. Here we discuss a number of physical layer techniques that are enabling the broadband wireless technologies to move forward by meeting some of these QoS requirements. The discussion addresses modulation, coding, multiple access, and diversity techniques. Some challenges along with some research evidences on the broadband wireless communication systems have also been presented in this chapter.KeywordsOrthogonal Frequency Division MultiplexCode Division Multiple AccessOrthogonal Frequency Division Multiplex SystemOrthogonal Frequency Division Multiple AccessTurbo CodeThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Body-centric wireless communications (BCWCs) have received increasing attention due to its potential application in areas such as E-health systems, home care, security, and entertainment. A compact and low-profile wearable planar inverted-F antenna (PIFA) with tuning function is presented for BCWCs in this paper. A two-thirds muscle-equivalent phantom is used to model the human's arm. By tuning the proper capacitance of the proposed antenna, the industrial, scientific and medical (ISM, 2.40–2.48 GHz), wireless broadband (WiBro, 2.3–2.39 GHz) and Universal Mobile Telecommunications System (UMTS, Rx 2.1–2.17 GHz) and meanwhile lower band can also cover 950–956 MHz.

The use of a wide range of radio stations of various generations in the Armed Forces of the RussianFederation has led to the impossibility of fully taking into account all their features when planningradio communications. For example, it becomes an extremely difficult task to take into account the entirelist of self-detected frequencies by the emissions of their own heterodynes of various radio stations,as well as frequencies prohibited for establishing and conducting radio communications. In this regard,the risks of lack of radio communication or violation of the rules for the use of the radio frequency rangehave increased many times, including in the units of military robotic complexes (RTK VN). The articlenotes that one of the biggest problems in creating a unified digital combat control system, the technicalbasis of which will be a wireless communication network - a radio communication network operating invarious frequency ranges, today is meeting the requirements of electromagnetic compatibility (EMC)and, in particular, meeting the requirements for the correct use of the radio frequency spectrum.To optimize the process of radio communication planning in the formations of the RTK VN, to increaseits efficiency and effectiveness, the article proposes to create and apply an automated system for monitoringthe assignment of radio frequencies based on a risk-based approach. It is shown that the riskorientedapproach when planning radio communications in the divisions of the RTK VN involves acomparative assessment of the nominal value of the assigned operating frequency with a list of selfdetectedfrequencies of each of the radio stations used, as well as with a list of prohibited frequencies forestablishing radio communications (frequencies for transmitting distress signals, etc.). It is reasonedthat this approach will reduce the risks of lack of radio communication or violation of the rules for usingthe radio frequency range. It will optimize the processes of automated planning of radio communicationsin the formations of the RTK VN and increase the efficiency and effectiveness of automated planningand management of radio communications during combat operations. The article describes thealgorithm of the automated control system for the assignment of radio frequencies. The software implementationof this algorithm involves the creation and storage in the appropriate memory area of libraries(databases) of the main prohibited frequencies defined by the legislation of the Russian Federation.In addition, these libraries (databases) store lists of self-reflected frequencies by the emissions of theirown heterodynes of all types of radio stations used, given in the technical description of each of theradio stations used.

With the advent of next generation (4G) broadband wireless communications, the combination of multiple-input multiple-output (MIMO) wireless technology with orthogonal frequency division multiplexing (OFDM) has been recognized as one of the most promising techniques to support high data rate and high performance. In particular, coding over the space, time, and frequency domains provided by MIMO-OFDM will enable a much more reliable and robust transmission over the harsh wireless environment. In this article we provide an overview of space-time (ST) coding, space-frequency (SF) coding, and space-time-frequency (STF) coding for MIMO-OFDM systems. Performance results show that STF coding can achieve the maximum diversity gain in an end- to-end MIMO-OFDM system over broadband wireless channels. Furthermore, for orthogonal frequency division multiple access (OFDMA), we propose a multiuser SF coding scheme that can achieve the maximum diversity for each user while minimizing the interference introduced from all the other users.

Summary form only given. Emerging demands for high data rate multimedia based services and high spectral efficiency are the key drives for the continued technology evolution in wireless communications. Recently, several advancements have been introduced for 3G wireless communication systems to further enhance the data rate and the system performance. However, due to the proliferation of wireless multimedia applications and services such as video teleconferencing, network gaming, and high-quality audio/video streaming, it is apparent that 3G wireless systems will be unable to comply with this ever increasing demand for broadband wireless services. The next generation wireless communication systems (namely, fourth generation (4G) or beyond 3G (B3G) systems) are expected to support much higher data rate services compared to evolving 3G systems (up to 100 Mbit/s in outdoor environments and up to 1 Gbit/s in indoor environments). The major technical challenges will be achieving high spectral efficiency and handling high frequency-selectivity due to the use of large bandwidth. Hence, it has become crucial to incorporate the recent technical advances in the physical layer into the future wireless systems. In this keynote speech, an overview of leading technological advances and future trends in the physical layer that enable truly ubiquitous broadband wireless capabilities will be presented. The topics include multiple-input multiple-output (MIMO) technologies, adaptive modulation, cooperative diversity, multicarrier CDMA, ultra wideband (UWB) transmission, and cognitive radio.

It is difficult to recognize Automatic Link Establishment (ALE) behaviors of a short-wave radio station, if we do not acquire the radio station's communication protocol standard. A method is proposed to recognize different ALE behaviors by using an improved unidimensional DenseNet. In this work, we directly recognize ALE signals in physical layer without the radio station's communication protocol standard. Hence, we can avoid difficulties in demodulation, decryption and so on. Actually, the original DenseNet is used extensively in the field of computer vision, so the original DenseNet is firstly adapted for the unidimensional input. And then, two parallel dense blocks are used in our improved unidimensional DenseNet, which could improve the capability of network to extract ALE signals' deep features. The experimental results show that the proposed method is able to recognize different ALE behaviors of a short-wave radio station. And improved DenseNet has better recognition performance than simple DenseNet. The simple DenseNet only contains one dense block. Finally, the results of comparison experiments also show that some classic networks have worse performance in ALE behaviors recognition, such as LeNet-5, ResNet-34, and DenseNet-121.

현대전의 전장 환경에서는 효율적인 작전 수행을 위하여 통합 군 무기체계 간 상호 운용이 필수적이다. 특히 네트워크 중심의 전자전 시스템에서 대부분의 최신 무기체계는 무선 통신을 위하여 전자파를 이용하므로 인접 무기 체계 간 상호 간섭의 영향에 취약하다. 본 논문에서는 통합 군 무기 체계에서 사용하는 대표적인 무선 통신 시스템을 중심으로 확산과 비확산 통신 방식으로 나누어 모델링하였다. 그리고 다양한 간섭원을 생성하여 인접 레이다 및 통신 간섭원에 의한 영향을 모의시험을 통하여 분석하였다. 모의시험 결과, 인접 간섭원의 변조 방식과 중첩 대역폭에 따라 피간섭 수신기의 성능이 영향을 크게 받는 것을 확인하였다. 본 연구 결과는 향후 통합 군 통신 무기 체계 간 상호 운용을 위한 간섭 보호 기준을 정립하는데 활용될 것으로 기대한다. It is essential for the combined military weapon system to be equipped with interoperability for the efficient combat operation in the modern warfare environment. Since most of modern military systems utilize the electromagnetic wave for the radio communication in the network-centric warfare system, they can be vulnerable to the mutual interference among the adjacent combined military systems. In this paper, the typical radio communication systems are modeled with the modulation types of both spread and non-spread spectrum system. The various interference signals were generated for the simulation of the mutual interference influence from the adjacent radar and communication systems. The simulation results show that the detection performance of the victim communication receiver is seriously affected by the various interferences such as the types of modulation and the ratio of the overlapping bandwidth of the adjacent interferers. This result will be useful for defining the criteria of the interference protection in the combined military system for the interoperability in the future.

Municipal electric utilities’ role in telecommunications services

Wireless communications are expected to take place in increasingly complicated scenarios, such as dense urban, forest, tunnel, and other cluttered environments. A key emerging challenge is to understand the physics and characteristics of wave propagation in these environments, which is critical for the analysis, design, and application of advanced mobile and wireless communication systems. In this paper, we present a full-wave field-based computational methodology for radio wave propagation in complex urban environments. Both transmitting/receiving antennas and propagation environments are modeled by first-principles calculations. A system-level, large scene analysis is enabled by the scalable, ultraparallel algorithms on the emerging high-performance computing platforms. The proposed computational framework is verified and validated with semianalytical models and representative measurements.

In the blink of an eye, you may miss the 350 km/h high-speed train as it thunders by, not mentioning the 574 km/h French TGV track train (April 2007) or the 581 km/h Japanese JR-Maglev train (December 2003). Recently, there have been growing interests to deliver true broadband wireless internet services to high-speed train passengers. To provide the broadband wireless services in such a high mobility environment, a number of technical challenges should be tackled, such as the severe Doppler shift problem, fast fading channel characteristics, fast power control and fast handover issues. The focus of this talk is on the anti-Doppler problem techniques, mobility management and network architecture. (Note: This work was partially supported by NSFC No. 60772087, 863 High-Tech R&D Program No.2009AA01Z238, 111 Project No.111-2-14 and MoST Sino-Swedish Joint Research NO.2008DFA12160).

Here is to propose a demonstration of opportunistic wireless mesh networks for broadband wireless Internet access, supporting real-time services, e.g., of voice and video. The enabling technology is of the large-scale cognitive networking, which opportunistically utilizes network resources including both spectrum bandwidth and mesh radio (station) availability. We further demonstrate that: (1) vast saving in the deployment/planning costs of wireless mesh networks can be achieved by establishing fluid networks without predetermined topology; (2) Better (opportunistic) network resource utilization can be achieved to establish reliable communications over multiple wireless hops. The network performance therefore reaches its instantaneous maximum.