A simplified proof of the representation of functionals of diffusions

A simple proof is given for the stochastic integral representation of a Fréchet differentiable functional of the paths of a given diffusion process. The proof begins when the functional depends on one coordinate, then passes to (by appropriate conditioning) a perhaps more difficult case—when the functional depends on a finite number of coordinates—and finally, by approximation, to the general case.     

Performance of the decorrelator receiver for DS-CDMA mobile radio system employing RAKE and diversity through Nakagami fading channel

Multiple-access interference (MAI) and multipath fading are two of the most significant factors limiting the capacity and performance of direct-sequence code-division multiple-access (DS-CDMA) systems. In this paper, synchronous multiuser receivers that combine antenna diversity, RAKE reception, and a multipath decorrelator for MAI cancellation are analyzed in a Nakagami faded environment using a maximal ratio combiner or a selection combiner. A coherent binary phase-shift keying employing DS-CDMA is considered. Arbitrary branch correlation is also considered for any diversity order in the case of identical severity fading on the branches.     

Multi-User MIMO Mobile CDMA Uplink System Employing Turbo Coding and Joint Detection Through a Multipath Rayleigh Fading Channel

In this paper, a generalized multiple-input multiple-output (MIMO) antenna system that can be fitted to the uplink of a wireless communication system is considered for the general case of multi-user. At the transmitter, the information bits are Turbo coded, then interleaved and passed through a serial-to-parallel converter. The channel is assumed bad urban suffering from multipath Rayleigh fading resulting in inter-symbol and multiple access interferences (ISI and MAI). At the front-end of the receiver, a number of receiving antennas are used followed by a joint multi-user estimator based on the Minimum Mean Square Error Block Linear Equalizer (MMSE-BLE).Computer simulations demonstrate a significant performance improvement in both single user and multi-user cases.This paper depends in parts on that presented at the 11th European Wireless Conference, Cyprus, Nicosia, pp. 187–192, April 2005. Yasmine A. Fahmy was born in Guiza, Egypt, on June 4, 1976. She received the B.Sc., M.Sc. and Ph.D. degrees in Communication and Electronics engineering from Cairo University, Egypt on 1999, 2001 and 2005 respectively. She is presently an assistant professor at Cairo University, Egypt. Her current field of interest is wireless communication and channel estimation. Hebat-Allah M. Mourad received her B.Sc., M. Sc. and Ph.D. degrees in electrical communication engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983, she has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently associate professor there. Her research interests include optical fiber communications, mobile and satellite communications. Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Whos Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.     

Diversity Reception of an Asynchronous Blind Adaptive Multiuser Detector Through Correlated Nakagami Fading Channel

In this paper, blind adaptive multiuser detection (MUD) technique is developed for uplink transmission in multiuser space diversity DS-CDMA system to overcome multipath fading effect and multiple access interference. The system consists of a space diversity, a precombining blind adaptive detector (PBAD), and a weight adaptation technique based on the minimization of the mean output energy (MOE). The bit error rate (BER) performance of this receiver for asynchronous DS-CDMA signals with independent and correlated antenna branches under Nakagami fading channel for BPSK system is evaluated. It has been seen that the use of antenna diversity can yield substantial improvement in performance even if the correlation between the antenna elements is relatively large (up to 0.795). However, the large correlation values pose a significant reduction in the diversity gain in comparison with the zero correlation situation. It has also been confirmed by simulations that the PBAD provides a significant receiver performance in comparison with the RAKE receiver employing antenna diversity. Khodr A. Saaifan Born in lebanon 1978, received B.S.c. degree in electrical and electronics engineering (with honors) from Benha higher institute of technology, Benha, Egypt, in 2001, and the M.S.c. degree in communications from Cairo University, Giza, Egypt, in 2005. He is currently pursuing for the Ph.D. degree at the Cairo University. His current research interest includes space–time-coded transmission, multiple-input multiple-output (MIMO) systems, fading channels, equalization, turbo (iterative) processing, and wideband code division multiple access (WCDMA). Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Who's Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.     

Performance of Low Earth Orbit Satellite Systems with Coding

The effect of block, convolutional and Turbo coding on the probability of error and the capacity are investigated for CDMA Low Earth Orbit (LEO) Satellite systems. The model employed assumes a contaminated Gaussian traffic model to be more compatible with different population areas. The conventional Gaussian distribution can be considered as a special case.     

Failure rate of the inverse Gaussian-Weibull mixture model

Motivated by the idea that different causes of failure of a given system could lead to different failure distributions, a mixture of two-component distributions, one of which is the two-parameter Inverse Gaussian (IG) and the other the two-parameter Weibull (W), is proposed as a failure model. The IG-W mixture model convers several types of failure rates (FR's). It is shown that depending on the parameter values, the IG-W mixture model is capable of covering six different combinations of FR's, as one of the components has an upsidedown bathtub failure rate (UBTFR) or increasing failure rate (IFR) and the other component has a decreasing failure rate (DFR), constant failure rate (CFR), or IFR. A study is made for the mixed FR based on these six combinations.     

A π/4 crossed cascaded adaptive array for mobile satellite communications

Adaptive arrays in mobile communications based on any arbitrary performance criteria have many problems in tracking the desired signal at different interference angles relative to the desired one. To use the adaptive arrays efficiently in mobile communications, we need a system which is independent of interference angles. In this paper a system nominated as π/4 crossed cascaded adaptive array (π/4 CC) based on (for example) the well-known constant modulus algorithm (CMA) is suggested. It is a four elements adaptive array, each two elements are controlled by the CMA and they are crossed by 45° angle in the vertical plane. The proposed system is examined by computer simulation and compared with the conventional system. It is found that the conventional two elements array is suffering from the capture problem and its performance is degraded at certain interference angles e.g. 25, 50, 55°,…. When the interference power is equal to the desired signal, the proposed system outperforms the conventional one. Therefore, the suggested system is more suitable in mobile communications which employs CM modulation techniques such as FM, QPSK, GMSK,…. In this article the analysis of the CMA and the proposed system are considered in detail. The system under consideration can be used also for all other adaptive arrays employing LMS, PI, and Applebaum, etc. Copyright © 1999 John Wiley & Sons, Ltd.     

A MC-CDMA Mobile Communication System Employing Pre-Rake and Transmit Diversity

In this paper, a multi-carrier code division multiple access (MC-CDMA) downlink mobile communication system employing pre-rake and dual transmit diversity is proposed. It combines high spectral efficiency with an immunity to channel dispersion and fading. It also ensures small size, cost and power consumption of the terminal. Theoretical and simulation results for the system under consideration are obtained. Depicted results show appreciable improvements of the proposed system over those previously known.Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Whos Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.Hebat-Allah M.Mourad received her B.Sc, M.Sc and Ph.D degrees in Electrical Communication Engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983 she has been with the Electronics and Communications Department, Faculty of Engineering Cairo University and is currently associate professor there. Her research interests include mobile communications, satellite communications and optical fiber communications.Fatma A. Newagy received her B.Sc and M.Sc degrees in electrical communication engineering from Cairo University, Egypt in 1998 and 2002 respectively. Since 1999, she has been a research assistant with the Department of Electronics and Communications, Faculty of Engineering, Cairo University. She is pursuing her Ph.D. there. Her research interests include mobile communications and modulation techniques for spread spectrum and wireless communications.     

An efficient decision feedback with center sampling differential detector for restricted bandwidth fast Rayleigh channels

An efficient decision feedback technique (EDF) is proposed to improve the performance of premodulation Gaussian minimum shift keying (GMSK) signals. Center sampling differential detector (CSDD) over restricted bandwidth (BW) fast Rayleigh channels is employed. The intersymbol interference (ISI) is partially eliminated by using the conventional decision feedback (CDF) technique. In the present modification ISI is drastically eliminated by using EDF technique resulting in the minimization of probability of error. The new receiver structure, is useful in mobile radio (MR) and mobile satellite communications where power efficiency, synchronization and implementation complexity are of primary concern. Numerical results show that the receiver structure under consideration yields a superior performance in narrowband channels where conventional differential detector (CDD) becomes unusable.