This paper addresses some of the potential opportunities for achieving advances in radar systems and technology. It is not a summary of current interests in radar, nor is it a forecast of what 'will be', but is speculation about what 'could be' based on the limited experiences and personal biases of the writer. Included are the replacement of existing radars that have been in use for some time, 'on-the-shelf' concepts and demonstrated technology that have yet to be employed, a few new directions that might offer capabilities that do not currently exist, and areas of basic technology that could be further explored to provide new understanding and new capabilities. Although much is included in the paper, it is not meant to be an exhaustive enumeration of the many possible directions for future radar.
Digital Radio Mondiale (DRM) is a system that promises to reinvigorate the use of the broadcasting bands below 30 MHz. It offers a dramatic improvement in audio quality, not only improving the audio bandwidth and signal-to-noise ratio, but also countering the effects of selective fading and audible interference from other stations. It is also designed to support various features that will make receiver operation more user-friendly. This article describes the basic 'mechanics' of DRM and its features, which include station identification, alternative frequency lists and support for time-varying frequency schedules-of particular importance in HF broadcasting.
The Session Initiation Protocol (SIP) is considered to be a future powerful alternative to the H.323 standard as the signalling system for the dominant Voice over IP (VoIP) communications. This paper provides an in-depth analysis of SIP by describing the SIP protocol stack, summarising the main features of the protocol, and illustrating its architecture, message and operation. The paper also explains the architecture and the two key aspects of signalling interworking when SIP is interconnected with the PSTN.
For Part 1 see ibid., vol.14, no.2, p.61-72 (April 2002). Low-frequency radars have the potential to counter stealth efforts and detect low-flying targets beyond the horizon. Part 2 of this paper discusses approaches to target classification and the problems of vulnerability to jamming and operation in a densely populated frequency band. The anti-jamming capabilities of VHF radars are analysed based on measurements conducted with the FHR experimental radar LARISSA and it is demonstrated that electromagnetic compatibility (EMC) with other users of the band can be achieved using a spectral signal-shaping technique. The paper is completed by an overview of possible and existing VHF/UHF radar applications.
* Part I: Underlying technologies * Chapter 1: Cryptography for mobile security * Chapter 2: PKI in mobile systems * Chapter 3: The personal PKI * Chapter 4: The smartcard as a mobile security device * Chapter 5: Secure mobile tokens - the future * Part II: Network security * Chapter 6: UMTS security * Chapter 7: Securing network access in future mobile systems * Chapter 8: Public key based network access * Chapter 9: Security in personal area networks * Chapter 10: Towards the security of routing in ad hoc networks * Chapter 11: Security issues in a MobileIPv6 network * Part III: Mobile code issues * Chapter 12: Security for agent systems and mobile agents * Chapter 13: Security issues for downloaded code in mobile phones * Part IV: Application security * Chapter 14: Secure mobile commerce * Chapter 15: Securing the delivery of digital content over the Internet * Chapter 16: Security for future standardised DRM * Part V: The future * Chapter 17: Pioneering advanced mobile privacy and security
The demand for higher and higher quality images transmitted quickly over the Internet has led to a strong need to develop better algorithms for the filtering and coding of such images. The introduction of the JPEG2000 compression standard has meant that for the first time the discrete wavelet transform (DWT) is to be used for the decomposition and reconstruction of images together with an efficient coding scheme. The use of wavelets implies the use of subband coding in which the image is iteratively decomposed into high- and low-frequency bands. Thus there is a need for filter pairs at both the analysis and synthesis stages. This paper aims in tutorial form to introduce the DWT, to illustrate its link with filters and filterbanks and to illustrate how it may be used as part of an image coding algorithm. It concludes with a look at the qualitative differences between images coded using JPEG2000 and those coded using the existing JPEG standard.
M-commerce, or mobile commerce, is a major application domain for mobile devices, enabling users to perform commercial transactions wherever they go. However, these applications require a high level of security. In this paper, the special characteristics of m-commerce are identified and some important security issues considered.
Broadcasting within the traditional AM bands is set to change with the introduction of digital broadcasts. Wideband receiver architectures allow many of the advanced functions of standards such as Digital Radio Mondiale to be implemented and upgraded without changing the hardware. This article describes some of the design issues of wideband receivers and the performance of a practical receiver
Low-frequency radars have the potential to counter stealth efforts and detect low-flying targets beyond the horizon. This paper gives an overview of the fundamental properties of radars at metric wavelengths, based on research over the past few years conducted at the German Research Institute for High-Frequency Physics and Radar Techniques (FGAN-FHR). It provides an analysis of radar cross-section to underline the anti-stealth properties of the low-frequency range and presents simulations as well as measurement results to demonstrate the beyond-the-horizon detection and foliage penetration capability of metric waves. Specific clutter properties are highlighted.
This paper looks at the security issues that arise for the browsing, selection and delivery of digital content over the Internet. Particular emphasis is placed on the problems of finding security solutions for microtransactions (small items of content) and micropayments (low-value content), and the digital rights management issues concerning the protection of content after it has been delivered to consumers. The paper concludes with a description of the secure content delivery system developed during the SIBIS project, which addresses many of the issues raised.
The agent paradigm is currently attracting much research. A mobile agent is a particular type of agent with the ability to migrate from one host to another, where it can resume its execution. We consider security issues that need to be addressed before multi-agent systems in general, and mobile agents in particular, can be a viable solution for a broad range of commercial applications. This is done by considering the implications of the characteristics given to agents and the general properties of open multi-agent systems. The paper then looks in some more detail at security technology and methods applicable to mobile agent systems.
Connecting each house to a broadband access network represents an unprecedented opportunity to offer added-value services and broadband Internet access to residential users and expand the customer base beyond the corporate environment. Home networks, however, may be the last barrier to end-to-end multimedia service provisioning. Although a large number of houses have PCs, modems or multimedia network-enabled appliances, the majority are not equipped to support their interconnection, and most consumers are unwilling or cannot afford large-scale home rewiring. This paper reviews the available home-networking technologies and provides a comparison of the competing broadband in-home technologies. The focus is on technologies that do not require rewiring the home, either reusing the existing wiring or using wireless technology. The paper also discusses the residential gateway (RG) initiative, which provides a single point of convergence between the in-home and the access networks.
New methodologies, engineering processes and support environments are beginning to emerge for embedded signal-processing systems. The main objectives are to enable industry to field state-of-the-art products in less time and with lower costs, including retrofits and upgrades, based predominantly on commercial off-the-shelf (COTS) components and the model-year concept. One of the cornerstones of the new methodologies is the concept of rapid prototyping. This is the ability to rapidly and seamlessly move from functional design, to architectural design, to implementation, through automatic code generation tools, onto real-time COTS test beds. This paper tries to quantify the term 'rapid' and provides results-metrics-from two independent benchmarks: a radar and sonar beamforming application subset. The metrics show that the rapid prototyping process may be 16 times faster than a conventional process.
The software programmable multiprocessor architecture has been employed extensively over the past two decades for embedded signal-processing applications. However, the increased complexity of such systems has, in many cases, required the use of hardware acceleration to meet the growing time-critical aspects of the design. Today's field-programmable gate arrays (FPGAs) offer an alternative or additional acceleration platform, especially to an application-specific integrated circuit (ASIC). However, the traditional low-level development methods, such as schematic capture or hardware description languages (HDLs), employed to implement these hardware accelerated parts of the design result in a design lifecycle mismatch between the rapid development techniques available for the software programmable parts. This paper presents high-level design languages that enable users to generate netlists for FPGAs directly from high-level C-like languages, thereby offering an equivalent programming solution to that available with microprocessors. It details how one of these languages can be integrated into a high-level design flow for the rapid development of heterogeneous embedded signal-processing systems and presents results from a benchmark
Third generation mobile radio systems are currently being deployed in different regions of the world. Future systems beyond the third generation are already under discussion in international bodies and forums such as ITU, WWRF and R&D programmes of the European Union and in other regions. These systems will determine the research and standardisation activities in mobile and wireless communication in the next years. Based on experience of the third generation, future systems will be developed mainly from the user perspective with respect to potential services and applications including traffic demands. Therefore, the Wireless World Research Forum was launched in 2001 as a global and open initiative of manufacturers, network operators, SMEs, R&D centres and the academic domain. WWRF is focused on the vision of such systems-the Wireless World-and potential key technologies. This paper describes the international context of activities on systems beyond third generation, the goals, objectives and structure of WWRF, the user perspective as the starting point for a future system design and the key enabling technologies for the Wireless World.
Low-frequency radars have the potential to counter stealth efforts and detect low-flying targets beyond the horizon. This paper gives an overview of the fundamental properties of radars at metric wavelengths, based on research over the past few years conducted at the German Research Institute for High-Frequency Physics and Radar Techniques (FGAN-FHR). It provides an analysis of radar cross-section to underline the anti-stealth properties of the low-frequency range and presents simulations as well as measurement results to demonstrate the beyond-the-horizon detection and foliage penetration capability of metric waves. Specific clutter properties are highlighted
The explosive growth of the Internet and the subsequent demand for wireless data communications have led to data services being a major component in the standardisation process of many cellular mobile radio systems across the world. In GSM, the standardisation of the first phase of a new data service, initiated by the European Telecommunications Standards Institute (ETSI) and collectively known as Enhanced Data rates for GSM Evolution (EDGE), was finalised in 1999. The Enhanced Circuit Switched Data (ECSD) and Enhanced General Packet Radio Service (EGPRS) components of EDGE will enhance the existing GSM circuit-switched and packet-switched data services, respectively. This paper provides an overview of EGPRS and its performance.
Given the extensive growth in Internet traffic and increasing emphasis on service quality, one of the most crucial elements of IP backbone network design is to provide resilience to serious failures such as fibre-optic cable breaks. In previous years, the unit of bandwidth granularity for many IP backbone networks has grown from STM-1 (155 Mbit/s) through to STM-16 (2.4 Gbit/s), with STM-64 (10 Gbit/s) backbone circuits becoming prevalent. The increased concentration of traffic makes the IP backbone extremely vulnerable to failure, meaning a key challenge is to engineer embedded resilience into the network. This paper considers such issues and discusses various trade-offs associated with different levels of protection in an IP backbone network.
