Alexander Viessmann

A Spectrum Sensing Prototype for TV White Space in China

TV white space (TVWS) has been considered a favorable spectrum for sharing with other spectrum deficient technologies. There are three popular TV standards in China: the Digital Terrestrial Multimedia Broadcast (DTMB), China Multimedia Mobile Broadcasting (CMMB) and PAL-D/K (Phase Alternating Line -D/K). In this paper we present a prototype platform for experimental spectrum sensing, which is developed in-house to test TVWS spectrum sharing for all the three popular TV standards. We discuss the details on the prototype architecture, the spectrum sensing algorithms and the testing setup in this paper. The performance results show that the developed prototype platform can detect the signals from all the three TV standards robustly and efficiently.

A DVB-T2 receiver realization based on a software-defined radio concept

When DVB-T (Digital Video Broadcasting - Terrestrial) was introduced in the 1990s, it was impossible to foresee the upcoming demand for HDTV devices. Thus, a revision of this broadcasting standard, namely DVB-T2, was necessary. Recently finalized, this standard is targeting to high-definition television (HDTV). To pave the way to commercialization, an appropriate implementation concept and its corresponding validation are of utmost importance. Without a doubt, the most challenging requirements introduced by the DVB-T2 specification are an FFT (Fast Fourier Transform) size of up to 32k samples, 256-QAM (Quadrature Amplitude Modulation) and LDPC (Low-Density Parity-Check) coding with a block size of 64800 bits. Within this manuscript, the authors present a software-defined radio based realization of a demonstrator platform. This platform employs a combined DSP (Digital Signal Processor) and FPGA (Field-Programmable Gate Array) solution being capable of meeting these requirements.

A low-cost protocol and application for UWB localization

Range Radio by Advanced Ultra-Wideband Radio Technology, FP7-ICT-215669, www.euwb.eu) project has been an industry-led initiative of twenty-one major industrial and excellent academic organizations from Europe and Israel who have been targeting innovative improvement, adaptation, integration and application of short-range Ultra-Wideband Radio Technology (UWB-RT). EUWB has effectively leveraged and significantly enhanced the scientific knowledge base in the advanced UWB-RT and has provided sophisticated new applications enabled by UWB and highly demanded in several European key industrial sectors such as home entertainment consumer electronics, automotive, public transportation, and heterogeneous cellular networks. It is anticipated that the efficient exploitation of cross-layer functionalities will fertilize the successful application of UWB technology. Within EUWB, major fields of this emerging challenge have been identified, such as the cognitive radio related Detect-And-Avoid (DAA) technology and the localization and tracking (LT) technology. An important aspect is to design an LT protocol. In this manuscript the authors will first illustrate the technical approach of EUWB, giving a brief overview of the project. Then, the authors will propose a novel LT protocol and application. This application is tailored to operate also with UWB devices that do not fully comply with the previously proposed LT schemes which need specific physical and medium access control layer functionalities.

Petri Net Based Controller Concept For Cognitive Radios in Wireless Access Networks

This paper will give a detailed discussion about the authors view on Software Defined and Cognitive Radio. After an introduction on different aspects of software radio and a novel approach on cognitive radio is presented. As proof of concept a software defined cognitive radio demonstrator termed Falcon was built up which is described afterwards. The Falcon is entirely based on a modular signal processing concept. In particular, the receiver deploys modules which process and generate log-likelihood ratio (LLR) signals, hence, providing the capability of a plug-and-play-type reconfigurability. To the best knowledge of the authors, such a reconfigurability approach has not yet been pursued as consequently before.

On Spectrum Sensing for TV White Space in China

In the field of wireless communications the idea of cognitive radio is of utmost interest. Due to its advantageous propagation properties, the TV white space can be considered to become the first commercial application of cognitive radio. It allows the usage of secondary communication systems at non-occupied frequency bands. Within this paper, spectrum sensing algorithms are introduced for the three predominant Chinese TV standards DTMB, CMMB, and PAL-D/K. A prototype platform is presented and its underlying architecture based on a combination of DSP and FPGA is illustrated including the setup of the cognitive radio application. Furthermore, the performance of the sensing algorithms implemented on the prototype platform is shown in comparison to simulation results.

Java implementation of localization and tracking application based on HDR-UWB platform

In recent years extensive research was carried out in order to develop applications for the Ultra-Wideband (UWB) technology and to resolve the practical challenges in implementing an efficient UWB communication system utilizing the UWB impulse radio for precision localization. ToA (Time of Arrival) or TDoA (Time Difference of Arrival) of ranging frame are widely used because ToA and TDoA provide high accuracy due to the high time resolution with high bandwidth of IR-UWB (Impulse Radio - UWB) signal. HDR-UWB (High Data Rate -UWB) uses MB-OFDM (Multi Band - Orthogonal Frequency Division Multiplexing) to transmit signals, which can reach a data rate of 200 Mbit/s. In this paper a Java implementation of an active LT (Localization and Tracking) method based on a HDR-UWB platform is investigated. The hardware is composed of three UWB anchors, one UWB tag and one UWB location coordinator, which is connected to a PC (Personal Computer) or a PDA (Personal Digital Assistant). The Java program, which is hosted on the PC or PDA, is used to instruct the UWB coordinator to send and receive the UWB ranging frame and localize the tag. ToA is used as a ranging parameter in this work to measure the distance between the used UWB anchors and the UWB tag. The most important aspect is to reduce the jitter of ToA caused by CPU processing and the clock drift between UWB anchors and UWB tag. In this paper a 3-way ranging mechanism to minimize the clock drift is deployed. In addition the use of the JPCAP (Java Package for CAPturing) library in Java reduces the jitter of the ToA.

A localization and tracking application for UWB

An increasing demand for applications in the area of Ultra-Wideband Radio Technology led to the EUWB (Coexisting Short Range Radio by Advanced Ultra-Wideband Radio Technology, FP7-ICT-215669, www.euwb.eu) project, which has been started in April 2008. The goal of this industry-led initiative of major industrial and excellent academic organizations is the improvement, integration, and the applications of UltraWideband Radio Technology (UWB-RT). The EUWB project has significantly enhanced the scientific knowledge base in the UWB-RT and has provided sophisticated new applications enabled by UWB and highly demanded in several European key industrial sectors such as home entertainment consumer electronics, automotive, public transportation, and heterogeneous networks. Without a doubt, the efficient exploitation of cross-layer functionalities will lead to successful applications of UWB technologies. Beside the cognitive radio related technology, namely the Detect-And-Avoid (DAA) technology, the localization and tracking (LT) technology is a major aspect of EUWB, in particular the underlying LT protocol. Within the scope of this manuscript, the authors will give a brief overview of EUWB by illustrating its technical approach. Furthermore, the authors will describe a novel LT protocol as well as its application to a typical scenario. This application is tailored to operate also with UWB devices that do not fully comply with the previously proposed LT schemes which need specific physical and medium access control layer functionalities.

Cognitive Radio Prototyping

Future wireless systems have been evolving toward a broadband and open architecture for efficient multi-service operation, which will have a great impact on the terminal and infrastructure component design methodology for supporting multiple radio schemes. Cooperation in wireless networks, requiring cognitive radio implementations, will facilitate a new dimension in the evolution of multimedia communications. The growing price pressure requires ever increasing high levels of integration efficiency, of flexibility and of future proofness at the same time, setting out in the digital baseband domain. In this communication, the authors will illustrate a platform based prototyping process, setting out from the paradigm developed in the IST-27960 STREP URANUS (UNIVERSAL RADIO-LINK PLATFORM FOR EFFICIENT USER-CENTRIC ACCESS). URANUS investigates the design of a universal radio link platform able to be incorporated in any existing proprietary and standardized wireless system in a seamless way, to ease the introduction of future personalized communications and reconfigurable air interfaces.

Concept and design of a cognitive radio prototyping platform

The increasing demand for higher data rates in communication systems requires an efficient utilization of the limited frequency spectrum resource. Therefore, cognitive radio aspects are of utmost interest. The authors propose a reconfigurable cognitive radio platform which combines the advantages of the flexibility of a digital signal processor with the efficient parallelization capabilities of a field-programmable gate array. Since the ever increasing computational complexity complicates the dimensioning of such platforms, scalability and modularity was a crucial design constraint for the presented concept.

A cognitive radio realization based on a Petri net approach

Reconflgurability of transceivers for wireless communication systems such as GSM, UMTS, WiMAX and WLAN will become increasingly important. Therefore, a flexible and reliable software and hardware architecture based on the software-defined radio (SDR) paradigm is a meaningful concept. SDRs have paved the way towards cognitive radios (CR), which are based on SDRs that additionally sense their environments, track changes, and react upon their findings. A CR is an autonomous unit in a communications environment that frequently exchanges information with the networks it is able to access as well as with other CRs. A tool is required for the description and design of the multitude of concurrent processing tasks running on the CR. Petri nets are both a simple and strong solution and are recommendable to deploy them for these demands. In this manuscript, the authors present a concept for a CR as well as the hardware demonstrator realization. This demonstrator was developed by the authors and makes use of a digital signal processor (DSP) in combination with field-programmable gate arrays (FPGAs). The authors will describe the solution also in view of the recent developments of IEEE 802.22.