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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes In Wireless Channels, Le Chung Tran, Tadeusz Wysocki, Alfred Mertins, Jennifer Seberry
A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes In Wireless Channels, Le Chung Tran, Tadeusz Wysocki, Alfred Mertins, Jennifer Seberry
Dr Le Chung Tran
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 …
Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz Wysocki
Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz Wysocki
Dr Le Chung Tran
Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) will be examined in this paper to advance either data rate or error performance in recently proposed Space-Time-Frequency Coded Multiband OFDM Ultra-Wideband (STFC MB-OFDM UWB) communication systems. It is shown that QOSTFCs can provide signi¯cantly better error performance, compared to the conventional MB-OFDM UWB (without STFCs) and to the Orthogonal STFCs (OSTFCs) of the same order, at the same data rate, without increasing the total transmission power. Another form of the enhancement would be that QOSTFCs can provide higher data rates with the same error performance, compared to OSTFCs.
Novel Constructions Of Improved Square Complex Orthogonal Designs For Eight Transmit Antennas, Le Chung Tran, Alfred Mertins, Jennifer Seberry, Tadeusz Wysocki, Sarah Adams
Novel Constructions Of Improved Square Complex Orthogonal Designs For Eight Transmit Antennas, Le Chung Tran, Alfred Mertins, Jennifer Seberry, Tadeusz Wysocki, Sarah Adams
Dr Le Chung Tran
Constructions of square, maximum rate complex orthogonal space–time block codes (CO STBCs) are well known, however codes constructed via the known methods include numerous zeros, which impede their practical implementation. By modifying the Williamson and Wallis-Whiteman arrays to apply to complex matrices, we propose two methods of construction of square, order-4n CO STBCs from square, order-n codes which satisfy certain properties. Applying the proposed methods, we construct square, maximum rate, order-8 CO STBCs with no zeros, such that the transmitted symbols are equally dispersed through transmit antennas. Those codes, referred to as the improved square CO STBCs, have the advantages …
Application Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Alfred Mertins, Le Chung Tran
Application Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Alfred Mertins, Le Chung Tran
Dr Le Chung Tran
This paper examines the application of Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) to advance either data rate or error performance in recently proposed Space-Time-Frequency Coded Multiband OFDM Ultra-Wideband (STFC MB-OFDM UWB) communications systems. It is shown that QOSTFCs can provide significantly better error performance, compared to the conventional MB-OFDM UWB (without STFCs) and to the Orthogonal STFCs (OSTFCs) of the same order, at the same data rate, without increasing the total transmission power. In other words, QOSTFCs can provide higher data rates with the same error performance, compared to OSTFCs.
Space-Time-Frequency Code Implementation In Mb-Ofdm Uwb Communications: Design Criteria And Performance, Alfred Mertins, Le Chung Tran
Space-Time-Frequency Code Implementation In Mb-Ofdm Uwb Communications: Design Criteria And Performance, Alfred Mertins, Le Chung Tran
Dr Le Chung Tran
This paper proposes a general framework of Space-Time-Frequency Codes (STFCs) for Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) communications systems. A great similarity between the STFC MB-OFDM UWB systems and conventional wireless Complex Orthogonal Space-Time Block Code (CO STBC) Multiple-Input Multiple-Output (MIMO) systems is discovered. This allows us to quantify the pairwise error probability (PEP) of the proposed system and derive the general decoding method for the implemented STFCs. Based on the theoretical analysis results of PEP, we can further quantify the diversity order and coding gain of MB-OFDM UWB systems, and derive the design criteria for STFCs, …
Novel Cooperative Communication Schemes For Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Xiaojing Huang, Alfred Mertins, Eryk Dutkiewicz
Novel Cooperative Communication Schemes For Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Xiaojing Huang, Alfred Mertins, Eryk Dutkiewicz
Dr Le Chung Tran
Cooperative communication has been intensively considered for general wireless and sensor networks. However, it has been almost untouched in Space-Time-Frequency Coded Multi-band OFDM Ultra-Wideband (STFC MB-OFDM UWB) systems. This paper thus proposes two cross-layer designs for cooperative communication, namely Simple Cooperative Communication Scheme (SCCS) and Advanced Cooperative Communication Scheme (ACCS), in slow fading scenarios. In the former, nodes always cooperate with one another despite the possibly erroneous reception at the partner nodes, while in the latter, nodes cooperate only in the case of successful reception. Simulations show that these schemes may considerably improve the performance of STFC MB-OFDM UWB without …
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
Dr Le Chung Tran
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 …
Unitary Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, E. Dutkiewicz, Xiaojing Huang
Unitary Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, E. Dutkiewicz, Xiaojing Huang
Dr Le Chung Tran
In a multiple-input multiple-output (MIMO) multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) system, coherent detection where the channel state information (CSI) is assumed to be exactly known at the receiver requires the transmission of a large number of symbols for channel estimation, thus reducing the bandwidth efficiency. This paper examines the use of unitary differential space-time frequency codes (DSTFCs) in MB-OFDM UWB, which increases the system bandwidth efficiency due to the fact that no CSI is required for differential detection. The proposed DSTFC MB-OFDM system would be useful when the transmission of multiple channel estimation symbols is impractical or …
Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz A. Wysocki
Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz A. Wysocki
Dr Le Chung Tran
Though cooperative communication has been intensively examined for general wireless systems, such as mobile and ad-hoc networks, it has been almost unexplored in the case of Space-Time-Frequency Coded Multi-band OFDM Ultra-Wideband (STFC MB-OFDM UWB). This paper proposes a framework of cooperative communication in such systems where nodes are equipped with only one antenna. Simulation results show that cooperative communication might, in some cases, provide better error performance than non-cooperative communication without any additional transmission power.
Novel Constructions Of Improved Square Complex Orthogonal Designs For Eight Transmit Antennas, Le Chung Tran, Tadeusz Wysocki, Jennifer Seberry, Alfred Mertins, Sarah Adams
Novel Constructions Of Improved Square Complex Orthogonal Designs For Eight Transmit Antennas, Le Chung Tran, Tadeusz Wysocki, Jennifer Seberry, Alfred Mertins, Sarah Adams
Dr Le Chung Tran
Constructions of square, maximum rate complex orthogonal space-time block codes (CO STBCs) are well known, however codes constructed via the known methods include numerous zeros, which impede their practical implementation. By modifying the Williamson and Wallis-Whiteman arrays to apply to complex matrices, we propose two methods of construction of square, order-4n CO STBCs from square, order-n codes which satisfy certain properties. Applying the proposed methods, we construct square, maximum rate, order-8 CO STBCs with no zeros, such that the transmitted symbols are equally dispersed through transmit antennas. Those codes, referred to as the improved square CO STBCs, have the advantages …
Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb With Dual Carrier Modulation, Alfred Mertins, Le Chung Tran
Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb With Dual Carrier Modulation, Alfred Mertins, Le Chung Tran
Dr Le Chung Tran
In a multiple-input multiple-output (MIMO) multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) system, coherent detection where the channel state information (CSI) is assumed to be exactly known at the receiver requires the transmission of a large number of symbols for channel estimation, thus reducing the bandwidth efficiency. This paper examines the use of unitary differential space-time frequency codes (DSTFCs) in MB-OFDM UWB, which increases the system bandwidth efficiency due to the fact that no CSI is required for differential detection. The proposed DSTFC MB-OFDM system would be useful when the transmission of multiple channel estimation symbols is impractical or …
Space-Time-Frequency Trellis Coding For Multiband Ofdm Ultra Wideband Wireless Systems, Phuc Ngoc Le, Le Chung Tran, Farzad Safaei
Space-Time-Frequency Trellis Coding For Multiband Ofdm Ultra Wideband Wireless Systems, Phuc Ngoc Le, Le Chung Tran, Farzad Safaei
Dr Le Chung Tran
In this paper, the application of space time trellis codes to multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) systems is investigated. We propose a coding scheme that could fully exploit all the available channel diversity, including space diversity, frequency diversity and inter-subband diversity. Performance of the proposed system is compared with that of the conventional MB-OFDM UWB system in terms of frame error rate (FER). Simulation results show that this system outperforms the conventional one. As an example, an improvement of at least 5 dB at FER=1E-2 could be achieved over the IEEE 802.15.3a channel modes of CM1 and …
On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins
On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins
Dr Le Chung Tran
Space-Time-Frequency Codes (STFCs), which haverecently been proposed in the literature for Multiband OFDMUltra-Wideband (MB-OFDM UWB) systems to improve thesystem capacity, error performance and wireless communicationrange, are all constructed based on orthogonal structures. Thispaper examines the application of Quasi-Orthogonal STFCs(QOSTFCs) to enhance further either data rate or error performancein the recently proposed STFC MB-OFDM UWB systems.It will be shown that QOSTFCs can provide significantly bettererror performance, compared to the conventional MB-OFDMUWB (without STFCs) as well as to the Orthogonal STFCs(OSTFCs) of the same order, at the same data rate, withoutincreasing the total transmission power. Equivalently, QOSTFCscan provide higher data rates with …