72 research outputs found
Analysis of DVB-H network coverage with the application of transmit diversity
This paper investigates the effects of the Cyclic Delay Diversity (CDD) transmit diversity scheme on DVB-H networks. Transmit diversity improves reception and Quality of Service (QoS) in areas of poor coverage such as sparsely populated or obscured locations. The technique not only povides robust reception in mobile environments thus improving QoS, but it also reduces network costs in terms of the transmit power, number of
infrastructure elements, antenna height and the frequency reuse factor over indoor and outdoor environments. In this paper, the benefit and effectiveness of CDD transmit diversity is tackled
through simulation results for comparison in several scenarios of coverage in DVB-H networks. The channel model used in the simulations is based on COST207 and a basic radio planning
technique is used to illustrate the main principles developed in this paper. The work reported in this paper was supported by
the European Commission IST project—PLUTO (Physical Layer DVB Transmission Optimization)
Classical and Bayesian Linear Data Estimators for Unique Word OFDM
Unique word - orthogonal frequency division multiplexing (UW-OFDM) is a novel
OFDM signaling concept, where the guard interval is built of a deterministic
sequence - the so-called unique word - instead of the conventional random
cyclic prefix. In contrast to previous attempts with deterministic sequences in
the guard interval the addressed UW-OFDM signaling approach introduces
correlations between the subcarrier symbols, which can be exploited by the
receiver in order to improve the bit error ratio performance. In this paper we
develop several linear data estimators specifically designed for UW-OFDM, some
based on classical and some based on Bayesian estimation theory. Furthermore,
we derive complexity optimized versions of these estimators, and we study their
individual complex multiplication count in detail. Finally, we evaluate the
estimators' performance for the additive white Gaussian noise channel as well
as for selected indoor multipath channel scenarios.Comment: Preprint, 13 page
System design and validation of multi-band OFDM wireless communications with multiple antennas
[no abstract
Adaptive Time-Frequency Codes for Ultra-Wideband
This paper investigates inter-piconet interference (IPI) in the multi-band orthogonal frequency division multi-plexing (MB-OFDM) ultra-wideband (UWB) standard. IPI is caused when the time-frequency codes (TFCs) that delineate MB-OFDM piconets collide. An upper-bound on the severity of the IPI problem is obtained through a theoretical analysis of data-rate-specific punctured convolutional codes. Using these results, several methods for adaptive TFCs are proposed and analyzed. Comprehensive simulation results show how packet error rates (PERs) for simultaneous operating piconets (SOPs) can be improved by up to 2 dB by enabling adaptive TFCs at the transmitter. Several combinations of data rate, TFC, channel model and interferer power are studied
Cross-Layer Resource Allocation for MB-OFDM UWB Systems
ISBN 978-953-3076461-0International audienc
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