IP communications in air traffic control (ATC)

Although established some 60 years ago voice communications is still the sole means to separate and guide aircrafts. Voice communication systems are therefore amongst the most critical installations in air traffic control (ATC). Frequentis was the first to introduce PCM (pulse code modulated) based equipment for ATC worldwide and is on the leading edge of steering into the world of packetized voice communications. VoIP is the emerging voice communication technology which has already proven to provide satisfactory service for commercial applications. However, in ATC a number of requirements exceeding commercial applications have to be met. The voice communication system for ATC integrates radio communication as a prime service. Delays generated by the system therefore directly affect the performance on the radio channel and need to be extremly low. Both the radio control (push-to-talk, PTT) and the voice content need to be processed and delivered in a timely manner. SIP (session initiated protocol) based signalling represents a promising approach to tackle the delay problem. In addition, voice communication systems are required to provide high availability figures. VoIP based systems strongly rely on the communications infrastructure as they are distributed by nature. Resilient packet ring structures allow for these high availablity figures for the communications infrastructure.     

Design and performance analysis of an advanced, narrowbandintegrated voice/data mobile radio system

Private land mobile communications have experienced significant demand for increased capacity and for new services, but congestion within the currently allocated 450 and 800 MHz bands has severely limited the capability of present generation systems to meet this demand. This paper proposes a narrowband integrated voice/data mobile radio system which triples current voice traffic capacity and simultaneously provides capacity for mobile data communications such as mobile data terminals, automatic vehicle location, and mobile facsimile by utilizing the silence gaps inherent in speech. The system is designed to fit within the narrowband 25 kHz channels in the 450 and 800 MHz frequency bands, and thus the system can replace existing private land mobile radio systems with minimum impact. The centerpiece of the system design is an evolutionary multiplexing and access control technique known as Packetized Data, Voice Dedicated (PDVD) Burst Switching which allows transmission of data within the silence gaps inherent in speech. Simulation results for various voice and data traffic loads show the flexibility and efficiency of the proposed narrowband integrated voice/data mobile radio system     

空天地一体化通信网络发展愿景与挑战

从未来6G网络的愿景出发,首先讨论了空天地一体化的网络愿景,提出了一体化的网络架构。在分析了卫星通信息和空基通信系统的特点后,给出了未来空天地一体化通信网络的应用场景。然后从网络结构、通信设施与设备及空口技术等3个方面详细阐述了当前一体化网络的发展现状与技术挑战。最后总结了当前地面通信运营商在空天地一体化网络中的尝试,提出非地面网络具有明显的覆盖优势和长距离通信的低时延网络服务优势,可以帮助运营商提供低成本的普遍服务及扩展现有的通信服务,实现收入增长。     

The Military and Air Traffic Control

The Department of Defense currently operates about 30 000 aircraft, the largest most varied single fleet of aircraft of those using the National Aviation System (NAS). For this and other important reasons discussed herein, military participation in evolving an efficient and effective NAS forces consideration of a number of important issues by the developers and operators of any future Air Traffic Control (ATC) system. These issues range from those critical aspects of national security and the sovereignty of our air space, through major economic factors in equipping military aircraft and facilities for operation in the NAS, to the necessity for optimizing safety and using efficiently the air space of the world. This paper discusses the roles of the military, both as a user and operator of ATC systems and as a developer of ATC related systems and equipments. The different areas of the NAS in which interfaces exist between the civil and military are defined. These areas include operations, organizational interfaces, and equipment and facility interfaces and in many cases are covered by formal agreements. By way of illustration, two typical military flights are used to show the combined interaction of a military aircraft with both civil and military ground facilities. Communications, navigation, and surveillance requirements are discussed with respect to the various phases of the example flights. An indication of the future ground systems (military and civil) with which military aircraft might interact emphasizes the heavy burden placed on the airborne electronics systems. The paper finally suggests possible approaches that can be considered to ensure that the airborne equipment will not only be compatible with the various military, FAA, and ICAO ground environments in which the aircraft will function, but will also provide some basis for standardization and for efficient spectrum utilization.     

地面空中接口在卫星移动通信的适用性研究

为发展星地一体化网络、真正实现全球无缝覆盖,研究地面移动通信空中接口在卫星通信的适用性是一种有效的解决思路。本文系统性的介绍了地面3G/4G移动通信空中接口和卫星通信系统架构,总结了现有文献关于地面空中接口在星上的适用性初步评估,对比分析了各种地面空中接口在卫星信道环境下的链路性能,为地面空中接口在星上应用的改进方向提供了参考依据。     

Three-dimensional cellular systems for aeronautical mobile radiocommunications

A new technique for designing three-dimensional cellular systems for VHF air/ground communications is proposed to solve the problem of frequency congestion for air traffic control (ATC) and flight services. In VHF air/ground communication systems, a radio line of sight (RLOS) between the aircraft and ground station must exist. The frequency reuse distance is reduced by using the radio horizon to block cochannel interferences. In the proposed system, cells of different sizes to cover different altitude ranges are separated by different reuse distances. With nine groups of channels, the altitude range from 740 ft to 45000 ft can be covered without interference. The proposed system utilizes the spectrum efficiently by covering a certain airspace according to a well-organized plan with the minimum number of frequency channels and cell sites. Thus, it has more frequency reuse than the current systems     

Aircraft interface with the future ATC system

The authors outline how the advantages of improved navigational accuracy can benefit both the individual aircraft and the air transportation system despite a mixed environment. The development of advanced navigation, flight planning, performance optimization, automatic guidance, and other capabilities in current and future flight management systems, together with the availability of digital communications between the airplane and ATC, suggests the need to review the potential airplane contributions to the ATC system of the future. A number of application areas utilizing current airborne flight management technology have been proposed for use with ATC that could provide significant operational benefits. These include: time-navigation applications in traffic management; multisensor navigation to provide automatic dependent surveillance; improved precision for approach, missed approach, and departure procedures; and improved navigational accuracy supporting reduced airway widths, holding pattern airspace, and aircraft separation standards. Several examples of operational benefits for operators and ATC during the transition period are identified, and the need for integrating these features into future ATC capabilities and procedures is stressed     

未来中国4G开放移动通信终端和网络接入架构

This paper relates to an advanced open mobile communication system and method of integrating the mobile communications, wireless access systems and wired communications into one common platform architecture for China＇s 4th generation mobile communications, supporting costeffective broadband voice, data and video services in wireless, mobile and wired environment with one single integrated mobile terminal device. The paper includes new architecture in the integrated mobile device and converged network access, and minimum modification in the existing mobile telecommunication infrastructures. This paper introduces the long-term evolution strategy for China＇s TDD system platform towards China＇s future 4G mobile communications.     

Operation of Current Navigation Aids and Future Prospects

This paper is designed as a survey document to be used as an overview and introduction to the various concepts and levels of complexity of current and future aids to air navigation. Major emphasis will be placed on identifying those technical and operational characteristics of each system concept and/or mechanization that have a significant impact upon both cockpit and ground-based communications and data processing. A representative bibliography is included to provide the reader the ability to pursue the subject further from an operational as well as a technical viewpoint. The object of this paper is to identify the relationship of air navigation aids to the flow and utilization of information in air navigation and air traffic control (ATC). Air navigation aids vary widely in both complexity and performance capability and these factors have a significant impact upon communications, data processing, and display, both in the air and on the ground.     

Future prospects of silicon photonics in next generation communication and computing systems

The recent progress is reviewed and future prospects of silicon photonics in next generation communication and computing systems are probed. Leveraging the many-billion-dollar complementary metal-oxide-semiconductor (CMOS) industry, silicon photonics has promising prospects for realising very large-scale electronic and photonic integrated circuits with thousands of optical components and millions of transistors in the future to support very demanding integrated systems needs of next generation computing and communications. There are also a number of significant challenges in fulfilling such prospects.     

地空通信和卫星通信组网实现电台的远程控制

地空话音通信在民航、军航以及许多军事指挥系统中有广泛应用.介绍了卫星通信系统与地空通信系统组网方式,实现20部地空电台的远程集中控制,完成区域指挥中心(SOC)对空指挥功能,并对其技术实现进行了探讨.     

Voice transmission quality of mobile satellite communications systems

Recently, a number of commercial digital mobile satellite communications systems have become operational, and the introduction of more systems is imminent. The voice transmission quality of the Inmarsat-aeronautical, Inmarsat-M and Inmarsat-B systems was evaluated and compared with the quality of the Inmarsat-A analogue communication system on the basis of subjective listener opinion assessments. From this evaluation it can be concluded that, under nominal operating conditions, the current generation of digital mobile systems may offer a perceived performance that surpasses that of the older Inmarsat-A analogue system, at least when measured in terms of transmission quality.     

SBS TDMA-DA system with VAC and DAC

This paper describes many of the design considerations involved in developlng the demand assignment (DA) subsystem of the TDMA satellite communication system for Satellite Business Systems. Each earth station has a satellite communications controller (SCC) which requests capacity to meet current voice and data traffic demands. A central reference station frequently reallocates capacity based on the requests of all the earth stations in a network. To minimize the amount of satellite capacity required, the SCC has a circuit-switching capability for voice calls as well as for digital data calls. Furthermore, the SCC employs voice activity, compression (VAC) and data activity cornpression (DAC), In which the amount of capacity requested is based on measured average speech activity as well as the number of off-hook voice ports and the number of off-hook data ports. Data calls are queued on a first-come, first-served basis when capacity is not immediateiy available. The reference station distributes excess capacity according to a nonlinear table lookup procedure so that the voice call blocking probability is equalized across the network. The DA system makes much more efficient use of satellite transmission capacity than a design with fixed-capacity trunk routes.     

An integrated mobile satellite broadcast, paging, communicationsand navigation system

The design of an integrated mobile satellite broadcast, paging, communications, and navigation system is described. Ku-band RadioSat ground stations will broadcast digital audio signals and data packets (including alphanumeric pages and group cells) to mobiles through a satellite to be launched in 1993. Each mobile radio will simultaneously receive L-band digital audio and data broadcasts from the satellite and L-band navigation broadcasts from the Global Positioning Systems (GPS) through a common omnidirectional mobile antenna and receiver front end. RadioSat mobile radios will use GPS broadcasts and differential corrections sent through the satellite to navigate with 2-m accuracy. With optional transmitters, RadioSat mobile radios can support two-way voice and data communications     

Future role of satellites in air traffic control

For the past several years the United States Federal Aviation Agency has recognized the potential of artificial earth satellites for improved air traffic control. This potential lies primarily in the areas of communications, navigation, and data acquisition, with communications being the area closest to realization. Projects completed by the Agency to date indicate that a communications satellite in synchronous orbit with the capability of several VHF channels employing voice modulation is feasible for implementation by 1970 or earlier. These projects also indicate that there is less certainty about realizing the navigation and data acquisition potential. Efforts are currently under way to define further the air traffic control requirements for satellite systems and to synthesize a communications satellite system. These efforts are designed to consider such major factors as system implementation timing, cost versus benefit, circuit discipline requirements, and system technical parameters. Experimental use will be made of the National Aeronautics and Space Administration ATS-B satellite in late 1966 to support this effort and some nonsatellite hardware development will also be undertaken.     

Desert Storm: air assault communications

The development of the US Army's 101st Airborne Division (Air Assault) Signal Battalion's command and control communications system from base-camp communications system into a system that provided division offensive communications which spanned more than 1000 miles and supported air assault ground and air combat offense operations in Iraq during Operations Desert Shield and Desert Storm is discussed. The forward operating base used the AN/TRC-170 multichannel tropospheric scatter communication system as the backbone and multichannel tactical satellite communication as the pivotal means for follow-on movement. The systems deployed by the battalion for base camp communications, covering force communications, and offensive communications are described