Paper Info
Title
Characterization of the wideband wireless channel in the context of DVB systems
Abstract
Recent radio systems (3G, DVB-T/H) present a wideband bandwidth possibly enlarging the capacity of the networks. The systems are interference-limited and thus an accurate radio network planning requires a refined characterization of the interference levels. A French research project called Semafor has been set up to investigate this characterization by means of two tools. First a hardware equipment is able to detect low interference levels by making use of antenna arrays and powerful algorithms. Second a coverage simulation tool is used. It is based on a propagation model able to estimate accurately large range echoes. System parameters like the interference level and SINR for DVB are simulated and validated by extensive measurement campaigns realized in the project with sophisticated testbeds. The radio network planning of wideband wireless systems does require prediction of the received power level by electromagnetic wave propagation prediction models. Furthermore the simulation of the reception quality may be greatly improved by taking also into account characteristics of the predicted wideband channel like the delay and angle dispersions. The simulation of diversity or MIMO performances clearly takes benefit from space-time predictions. But the same already applies when simulating simple transmit receive systems. In particular, in WCDMA networks presenting a 5MHz bandwidth, the intra-cell and extra-cell interference levels depend on the impulse response of channels from the base stations to the mobile station. The loss of orthogonality between the spreading codes, which is related to the intra-cell interference, is due to the delay dispersion in the propagation channel. The larger is the delay dispersion, the higher is the interference. Besides, in the 8MHz-bandwidth DVB-T/H networks, the delayed echoes of the propagation channel cause inter-symbol interferences when they arrive outside the FFT window of the demodulator. The length of the DVB symbols is increased by the guard interval to mitigate the effect of most of the delayed echoes. However distant interactions can generate excess delays greater than the guard interval, thus generating interference, especially around high transmitters overhanging wide areas as met in a DVB network. Then the prediction of the power delay profile or channel impulse response can be exploited to estimate the site-specific interference level in wideband systems such as WCDMA and DVB. The paper mainly focuses on DVB aspects, but most of the work about interferences applies to WCDMA. Assessing efficiently the multipath and the long delays can significantly improve the radio coverage and thus the radio network planning of such wideband systems. Following a FP6 IST European project (Antium) where a measurement equipment was developed, a French research project named Semafor has been initiated and aims at providing a unique (all systems in one) metrology platform that could be embedded in a light vehicle or portable by a human. All physical parameters of various waveforms (2G, 3G, Wimax, DVB) impacting the capacity and the quality of the networks are studied in a context of Radio Network Planning. Furthermore solutions to locate the transmitters (possible jammers) in a dense environment (Urban Area) are investigated. Convergence scenarios are studied and the main project results are validated by real field measurements. Two objectives of this project are discussed in this paper and consist in accurately measuring and finely predicting the interferences in various kinds of networks (UMTS, Wimax, DVB-T/H). On
Year
DOI
Venue
2008
10.1109/PIMRC.2008.4699766
Cannes
Keywords
Field
DocType
digital video broadcasting,radiofrequency interference,radiowave propagation,telecommunication network planning,wireless channels,3G-DVB-T/H radio systems,DVB systems,antenna arrays,coverage simulation tool,hardware equipment,interference detection,propagation model,radio network planning,wideband bandwidth,wideband wireless channel,DVB,Ray-tracing,wideband measurements
Wideband,Wireless,Ray tracing (graphics),Computer science,Computer network,Communication channel,Real-time computing,Bandwidth (signal processing),Radio network planning,Interference (wave propagation),Digital Video Broadcasting
Conference
ISBN
Citations 
PageRank 
978-1-4244-2644-7
3
0.59
References 
Authors
0
2
Name
Order
Citations
PageRank
Yoann Corre17613.64
Yves Lostanlen217720.28