Research on Mobile Communications in Microwave and Millimeter-Wave Frequency Ranges at CRL

Research activities at the Communications Research Laboratory (CRL), IAI,Japan, into new-generation mobile communications are described. Theseactivities are categorized into three areas: (1) cellular transmission in themicrowave frequency region, (2) street-cell and hotspot transmission in themillimeter-wave frequency region, and (3) software defined radio (SDR) basedmobile terminals. Prototypes have been developed and field-tested in eacharea. The prototypes and the field trial results are described, and aperspective on new-generation mobile communications is presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

微波毫米波平面共口径天线北大核心CSCD

随着无线通讯和雷达成像等现代无线系统的迅速发展和广泛应用,人们对系统前端的天线提出了更多的需求。共口径天线将多种不同频带或不同功能的天线集成在同一口径,通过在有限口径内对天线单元进行合理布局,显著提高空间利用效率,并在不同天线之间实现高隔离,确保各天线独立工作。根据辐射口径分布情况,共口径天线设计方法可以分为:嵌套技术、交错技术和复用技术。与立体型共口径天线相比,平面共口径天线具有尺寸小、重量轻、成本低、易于集成等优点。本文介绍了微波毫米波平面共口径天线的研究现状,重点介绍了基于交错技术和复用技术的毫米波平面共口径天线,并对共口径天线技术的发展进行了展望。     

Millimeter-Wave Soldier-to-Soldier Communications for Covert Battlefield Operations

Mobile ad hoc networking of dismounted combat personnel is expected to play an important role in the future of network-centric operations. High-speed, short-range, soldier-to-soldier wireless communications will be required to relay information on situational awareness, tactical instructions, and covert surveillance related data during special operations reconnaissance and other missions. This article presents some of the work commissioned by the U.K. Ministry of Defence to assess the feasibility of using 60 GHz millimeter-wave smart antenna technology to provide covert communications capable of meeting these stringent networking needs. Recent advances in RF front-end technology, alongside physical layer transmission schemes that could be employed in millimeter-wave soldier- mounted radio, are discussed. The introduction of covert communications between soldiers will require the development of a bespoke directive medium access layer. A number of adjustments to the IEEE 802.11 distribution coordination function that will enable directional communications are suggested. The successful implementation of future smart antenna technologies and direction of arrival-based protocols will be highly dependent on thorough knowledge of transmission channel characteristics prior to deployment. A novel approach to simulating dynamic soldier-to-soldier signal propagation using state-of-the-art animation-based technology developed for computer game design is described, and important channel metrics such as root mean square angle and delay spread for a team of four networked infantry soldiers over a range of indoor and outdoor environments is reported.     

Carrier Pulses at Microwave and Millimeter-Wave Frequencies

This paper discusses some recent experimental results obtained using special gallium arsenide point-contact diodes for the generation of phase-locked carrier pulses in the microwave and millimeter-wave bands. Several methods of generating such pulses are described. 11.2-Gc microwave phase-locked carrier pulses of about 1.0-nanosecond base duration have been generated at a 160-megabit/second rate. These microwave pulses, which are generated directly from a baseband signal, normally have peak power levels in excess of 0.5 mw. Millimeter-wave phase-locked carrier pulses have also been generated at 56 Gc. These very high frequency pulses have a base duration as short as 0.25 nanosecond and occur at a 160-megabit/second rate. Furthermore, phase-locked carrier pulses have been generated at frequencies as high as 89.6 Gc. A simple method of generating nonphase-locked 0.3-nanosecond millimeter-wave carrier pulses directly from 1.92 gigabit/second rate baseband pulses has also been investigated. The experimental arrangement used to demonstrate the "turn on" and "turn off" principle of transient carrier pulse generation is described.     

基于采样精度切换的毫米波无线通信空闲侦听机制研究

针对毫米波无线通信系统,提出了一种基于采样精度切换的低功耗空闲侦听方案,使得CSMA/CA下空闲侦听功耗与接收机解调所需高耗能模数转换器（ADC）功耗互相独立.具体而言,在空闲侦听状态,接收机使能极低功耗的1比特ADC和所提的1比特采样精度广义似然比包检测器来捕获突发包的到达;一旦捕获成功,接收机切换到原高精度ADC来解调数据包,进而保持了解调性能.该文推导并验证了所提方案中包到达检测器的虚警概率（FAP）和漏检概率（MDP）表达式.仿真结果表明,该方案与现有方案相比可显著降低空闲侦听功耗,并获得优异的检测性能.     

Millimeter-Wave Propagation Channel Characterization for Short-Range Wireless Communications

This paper presents and analyzes the results of millimeter-wave 60-GHz frequency range propagation channel measurements that are performed in various indoor environments for continuous-route and direction-of-arrival (DOA) measurement campaigns. The statistical parameters of the propagation channel, such as the number of paths, the RMS delay spread, the path loss, and the shadowing, are inspected. Moreover, the interdependencies of different characteristics of the multipath channel are also investigated. A linear relationship between the number of paths and the delay spread is found, negative cross correlation between the shadow fading and the delay spread can be established, and an upper bound exponential model of the delay spread and the path loss is developed to estimate the worst case of the RMS delay spread at given path loss. Based on the DOA measurements that are carried out in a room [line of sight (LOS)] and in a corridor with both LOS and nonline-of-sight (NLOS) scenarios, radio-wave propagation mechanisms are studied. It is found that considering the direct wave and the first-order reflected waves from smooth surfaces is sufficient in the LOS cases. Transmission loss is very high; however, diffraction is found to be a significant propagation mechanism in NLOS propagation environments. The results can be used for the design of 60-GHz radio systems in short-range wireless applications.     

Solid-State Microwave and Millimeter-Wave Sources Development--A Personal Account

The personal experience with the development of solid-state microwave and millimeter-wave sources in the late 1960's and early 1970's is described.     

固态微波毫米波器件技术进展

固态微波毫米波半导体材料与器件、固态微波毫米波电路与模块、毫米波与太赫兹技术以及新型固态微波毫米波器件在近年来有很大的发展,在相控阵雷达、电子战、军民用通信领域有广泛的应用前景。当前这些器件应用较为集中于各类T/R组件。文章按固态微波毫米波半导体材料与器件、固态微波毫米波电路与模块、毫米波与太赫兹技术以及新型固态微波毫米波器件的顺序,概要介绍了固态微波毫米波技术的新进展。     

Cable Communications in Japan

Japanese coaxial toll systems at the end of the fiscal year 1970 had grown to 29 980 km of coaxial cable (including both tubes of two-tube systems). In the next seven years, 1971 to 1977, the requirement is expected to be three times this capacity. Cable transmission systems fully utilizing modem electronics and communication engineering techniques are being developed to best meet this expected growth and to provide new wider band services.     

Data Communications in Japan

Aspects of data communications in Japan are broadly summarized in this paper. First, various networks for data communication are described and some examples of data communication services using these networks are mentioned. Next, some topics in data communication technology are outlined. Topics include two large-scale computer projects and R&D on pattern recognition techniques in the data-processing field, standard modems now in use and new modems for PCM transmission and other uses in the data transmission field, optical character readers (OCR) and an audio-response unit, as well as various printers in the data terminal equipment field.     

Optical Communications in Japan

This paper reviews research and developmental activities in optical communications currently under way in Japan. Three major systems: 1) atmospheric optical communication systems, 2) optical-cable systems, and 3) lens-waveguide systems, using various types of lasers and newly developed optical devices and components, have been extensively studied at the Electrical Communication Laboratories of Nippon Telegraph and Telephone (NTT) and other electronic manufacturing companies in Japan.     

我国微波技术与微波通信的进展

本文论述我国在微波通信领域已取得或正在开展的一些基础性研究工作以及发展状况。包括微波技术方面的发展水平；微波通信的几种主要形式及其发展水平。     

Low-Loss and Wideband Package Transitions for Microwave and Millimeter-Wave MCMs

This paper presents high-performance flip-chip, through-substrate via and board-level BGA transition designs applicable in microwave and millimeter-wave multichip module (MCM) assemblies. Full-wave electromagnetic analysis was performed to achieve optimized transition structures. Interconnection test structures were fabricated in ceramic substrates and their performance was validated using on-wafer scattering parameter measurements. Both the flip-chip transition and the through-substrate via transition with a height of 800 mum exhibited return losses better than 25 dB and 20 dB, respectively, with low transmission losses up to 50 GHz. Furthermore, the wideband board-level BGA transition with a standoff height of 500 showed low insertion loss (< 0.5 dB) over a wide frequency range, from direct current (dc) up to 32.5 GHz.     

Mobile Radio Communications in Japan

After a short historical sketch of mobile communications in Japan, technical problems and future prospects are described. The peculiarities characteristic of mobile communication include complicated radio propagation and requirements for continuous communication and determination of mobile subscribers' location. This paper discusses major problems of future mobile communication, for example, radio propagation, controlling, and switching and radio equipment involved in meeting the future demands of a large number of subscribers over widespread service areas. Effective use of an electronic switching system will enable the mobile communication network to be integrated with existing fixed communication networks.     

Broadcasting Multi-beams Antenna Subset Modulation for Secure Millimeter-Wave Wireless Communications

Due to the increasing demand for wireless communications, spectral efficiency of transmission schemes has gained a great concern recently. Also, achieving secure wireless communications is of high importance. Recently, physical layer security has been intensively investigated as an extra layer of protection for wireless communications. Directional modulation (DM) has been proposed as a mean to implement physical layer security. Antenna subset modulation (ASM) is a low complexity single beam DM technique suitable for millimeter-wave communications. The small wavelengths nature of millimeter-wave band is exploited to equip a transmitter with a large antenna array, and by randomly choosing few elements of this array for transmitting a symbol, secure communication in a single direction is obtained. This paper provides a study for the performance of broadcasting multi-beams antenna subset modulation (MASM) in which it is desirable to broadcast data streams to different receivers. A statistical model has been driven, and the symbol error rate of MASM using QPSK and secrecy capacity are obtained. Simulation results show that ASM can be used efficiently for multidirectional broadcasting communication, while maintaining its inherent security.     

Limitations of Microwave and Millimeter-Wave Mixers Due to Excess Noise

Previous analytical work on microwave and millimeter-wave mixers concentrated on circuit aspects, utilizing for the analysis a simple noise model consisting of shot and thermal noise sources at a constant temperature. However, measurements show that the excess noise created in the diode by hot electrons, intervalley scattering, and traps at the metal-semiconductor interface can be important, especially in millimeter-wave mixers. In this paper, the method of calculation of mixer noise performance in the presence of excess noise is given and its influence discussed for room-temperature, as well as for cooled, mixers.