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Full-Text Articles in Engineering
Polarization Diversity For Indoor Wireless Communications, Tadeusz Wysocki, Jason Uher, Beata J. Wysocki
Polarization Diversity For Indoor Wireless Communications, Tadeusz Wysocki, Jason Uher, Beata J. Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
As the demand for high wireless data rates in indoor environments grows, we must find new ways to increase the performance of wireless links in multi-path fading. One common way to do this is to add diversity in the form of spatial or temporal diversity through the application of space-time block codes (STBCs). Recently, a method for combining STBCs with polarization diversity has been presented that allows for modeling the changes in polarization with quaternion numbers, introducing space-time-polarization block codes (STPBCs). This presentation shows some results from an initial investigation into the quality of cross polarized channels as compared to …
On The Issue Of Decoupled Decoding Of Codes Derived From Quaternion Orthogonal Designs, Tadeusz Wysocki, Beata Wysocki, Sarah Spence Adams
On The Issue Of Decoupled Decoding Of Codes Derived From Quaternion Orthogonal Designs, Tadeusz Wysocki, Beata Wysocki, Sarah Spence Adams
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Quaternion orthogonal designs (QODs) have been previously introduced as a basis for orthogonal space-time polarization block codes (OSTPBCs). This note will serve to correct statements concerning the optimality of a decoupled maximum-likelihood (ML) decoding algorithm. It will be shown that when compared to coupled decoding, the decoupled decoding is only optimal in certain cases. This raises several open problems concerning the decoding of OSTPBCs.
Effect Of Sample Timing On Ls Channel Estimation, Jason Uher, Tadeusz Wysocki, Beata Wysocki
Effect Of Sample Timing On Ls Channel Estimation, Jason Uher, Tadeusz Wysocki, Beata Wysocki
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
As block coding and intelligent receiver combining in multi-antenna systems moves from the theoretical into the physical domain, it is necessary to apply robust analysis to the problems encountered with the development of real radio systems that are often overlooked during theoretical development of methods and processes. One such problem is the lack of synchronization between the transmitter and receiver sampling clocks. This text attempts to analyze the significance of poorly correcting for differences in the transmit and receive sample clocks by simulating the BER of an Alamouti space-time coded system under a variety of sample rates and clock offsets. …
Program Of The 3rd International Conference On Signal Processing And Communication Systems, Omaha, Nebraska, 28-30 September 2009
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
10 sessions; 2 poster sessions.
Schedule and Table of Contents.
Pre-Filtering Of Self-Encoded Spread Spectrum In Dense Multipath Channels, Won Mee Jang, Lim Nguyen
Pre-Filtering Of Self-Encoded Spread Spectrum In Dense Multipath Channels, Won Mee Jang, Lim Nguyen
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
We present pre-filtering methods of self-encoded spread spectrum (SESS) in dense multipath channels. SESS eliminates the need for traditional transmit and receive pseudo noise (PN) code generators. In this paper, we propose multipath management of SESS in dense multipath urban environments. We propose a transmitter pre-filtering method that retains only good paths that contribute to the data decision positively at the receiver, and eliminates undesirable paths. The proposed technique significantly improves the system performance while increasing the transmit power moderately.
Ergodic Capacity Of Cooperative Networks Using Adaptive Transmission And Selection Combining, Bao Q. Vo-Nguyen, Trung Q. Duong, Nguyen N. Tran
Ergodic Capacity Of Cooperative Networks Using Adaptive Transmission And Selection Combining, Bao Q. Vo-Nguyen, Trung Q. Duong, Nguyen N. Tran
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Closed-form expressions for ergodic capacity of repetition-based cooperative networks under adaptive transmission with selection combining are derived. According to the changing channel conditions, the source adapts its rate and/or power level while the relays simply amplify and then forward the received signals. Specifically, three different adaptive techniques are investigated under the assumption of independent Rayleigh fading channels: optimal simultaneous power and rate adaptation (OPRA), constant power with optimal rate adaptation (OPA) and channel inversion with fixed rate (TIFR). Among them, for an arbitrary number of relays, TIFR gives the worst channel capacity; OPRA gives the best channel capacity and ORA …
Correction To “The Theory Of Quaternion Orthogonal Designs”, Tadeusz Wysocki, Beata J. Wysocki, Sarah Spence Adams
Correction To “The Theory Of Quaternion Orthogonal Designs”, Tadeusz Wysocki, Beata J. Wysocki, Sarah Spence Adams
Department of Electrical and Computer Engineering: Faculty Publications (to 2015)
Seberry et al. claimed that even though the dual-polarized transmission channel cannot be considered as described by means of a single quaternionic gain, the maximum-likelihood (ML) decoding rule can be decoupled for orthogonal space–time-polarization block codes (OSTPBCs) derived from quaternion orthogonal designs (QODs) [1, Sec. IV]. Regretfully, a correction is necessary, and we will show that decoupled decoding using the method presented therein is only optimal for codes derived from certain QODs, not from arbitrary QODs as previously suggested.