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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Scarcely Populated Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz A. Wysocki, Beata J. Wysocki, Jos H. Weber
Scarcely Populated Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz A. Wysocki, Beata J. Wysocki, Jos H. Weber
Faculty of Informatics - Papers (Archive)
Interleaved coding-modulation (ICM) is a recently proposed method for ultra-wideband impulse radio (UWB-IR) systems. ICM exploits the concept of chip interleaving, allowing to alleviate the problem of inter-symbol and inter-pulse interference commonly present in high data rate UWB-IR systems. In this paper, previous work on ICM is extended to scarcely populated multi-user scenarios. A novel design of a deterministic chip interleaver based on time-hopping hyperbolic congruence sequences is proposed. Furthermore, the main parameters of the random and hyperbolic interleavers are reviewed. The obtained results indicate that the proposed type of interleaver yields similar performance to random interleavers but with the …
Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo
Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
In this paper, we expand the idea of spreading the transmitted symbols in OFDM systems by unitary spreading matrices based on the rotated Hadamard or rotated Discrete Fourier Transform (DFT) matrices proposed in the literature to apply to Space-Time Coded Multiple-Input Multiple-Output OFDM (STC-MIMO-OFDM) systems. We refer the resulting systems to as STC-MIMO Block Spread OFDM (STC-MIMO-BOFDM) systems. In the proposed systems, a multi-dimensional diversity, including time, frequency, space and modulation diversities, can be used, resulting in better bit error performance in frequency selective Rayleigh fading channels compared to the conventional OFDM systems with or without STCs. Simulations carried out …
An Adaptive Scalable Multiuser-Ofdm System For Multimedia Transmission Over Fading Channels, Ahmed Muthana M. Nadhim, Jianhua He, Jiangtao Xi, Zongkai Yang
An Adaptive Scalable Multiuser-Ofdm System For Multimedia Transmission Over Fading Channels, Ahmed Muthana M. Nadhim, Jianhua He, Jiangtao Xi, Zongkai Yang
Faculty of Informatics - Papers (Archive)
In this paper, an adaptive scalable multiuser-OFDM system was proposed for multimedia transmission over fading channels. The proposed adaptive algorithm can adapt according to the channel status information of each user's channel status. This algorithm dynamically changes according to the user's channel changes; this can keep fixed QoS at the physical layer. Another predefined QoS for different sessions and services to be provided for different users. This QoS can be guaranteed by multimedia scalability. Scalability can adapt to the service requirements, in terms of transmission data rate and bandwidth. As a result, a robust multimedia transmission scheme is achieved by …
A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes In Wireless Channels, Le Chung Tran, Tadeusz A. Wysocki, Alfred Mertins, Jennifer R. Seberry
A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes In Wireless Channels, Le Chung Tran, Tadeusz A. Wysocki, Alfred Mertins, Jennifer R. Seberry
Faculty of Informatics - Papers (Archive)
Although generation of correlated Rayleigh fading envelopes has been intensively considered in the literature, all conventional methods have their own shortcomings, which seriously impede their applicability. In this paper, a very general, straightforward algorithm for the generation of an arbitrary number of Rayleigh envelopes with any desired, equal or unequal power, in wireless channels either with or without Doppler frequency shifts, is proposed. The proposed algorithm can be applied to the case of spatial correlation, such as with multiple antennas in Multiple Input Multiple Output (MIMO) systems, or spectral correlation between the random processes like in Orthogonal Frequency Division …