Chaouki T. Abdallah

S. Raghavan, R. Jordan, H.N. Jerez, C.T. Abdallah, "Real-Time Streaming Over an IEEE 802.11b Based Wireless LAN Test Bed", IEEE International Conference On Personal Wireless Communications, pp.155-158, New Delhi, India, Dec. 2002. [pdf]
Abstract: Wireless LAN systems based in IEEE 802.11 have become a path-breaking innovation and have revolutionized the home, educational establishments and office network markets [2]. We have attempted to analyze a real-time video streaming issues over a wireless LAN test bed based on such a mature technology, in our paper. The creation of this test bed is an ongoing effort at the Electrical Engineering and Computer Engineering (EECE) Department at the University of New Mexico, Albuquerque, New Mexico, which shall serve to promote future research and development, under the aegis of Ibero American Science Science and Technology Education Consortium (ISTEC) [3].

F. Amato, M. Ariola,C. T. Abdallah, and C. Cosentino, "Application of Finite-Time Stability Concepts to the Control of ATM Networks", 40th Annual Allerton Conference on Communication, Control, and Computing, July 2002. [pdf] [ps]
Abstract:...

A. El-Osery, J. Rowher, and C. T. Abdallah, "Power Control Algorithms in Wireless Communications", Invited, Proceedings of SPIE (AeroSense), Vol. 4740, pp. 151-159, Orlando, FL, 1-5 April 2002. [pdf] [ps]
Abstract: This paper presents a comprehensive review of the published algorithms on power control for cellular systems. The majority of the research is focused on Code Division Multiple Access (CDMA) systems, although a small fraction of the reviewed literature pertains to Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA).

N. Herscovici, C. Christodoulu, R. Jordan and C.T. Abdallah, "Wireless Communications and Networking: An Overview", IEEE Antennas and Propagation Magazine,Vol. 44, No. 1, pp.185-193, Feb. 2002. [pdf]
Abstract: This paper presents an overview of wireless local-area networks (LANs) and wireless personal area networks (PANs), with emphasis on the two most popular standards: IEEE 802.1 1, and Bluetooth. While there are many such surveys in the current literature and online, we attempt here to present wireless LANs and PANS in a unified fashion as a viable alternative to wired LANs, while stressing the remaining challenges and limitations.

S. Raghavan, H.N. Jerez, R. Jordan, C.T. Abdallah, "Wireless Camera and Site Survey issues over an IEEE 802.11b based wireless network test bed", Proceedings of the 27th Annual IEEE Conference on Local Computer Networks (LCN'02), Tampa, FL, Nov. 2002. [pdf]
Abstract: Wireless LAN systems based on IEEE 802.11 have been a proved and sought after technological innovation, over the past few years. In this paper, we discuss some of the technical aspects for testing and deploying a wireless LAN system at the University of New Mexico, Albuquerque, New Mexico. This shall serve as a model test bed for future research and development, under the aegis of Ibero American Science and Technology Education Consortium (ISTEC).

C. T. Abdallah, and J. Chiasson, "Stability of Communications Networks in the Presence of Delays", Proceedings of the 3rd IFAC Workshop on Time Delay Systems, pp. 193-197, Santa Fe, NM, Dec. 8-10 2001. [pdf] [ps]
Abstract: In this paper, we present a study of the destabilizing effects of delay in communications networks. We the apply results from a companion paper to find the range of delays for which a Smith predictor controller guarantees the stability of an ATM/ABR network.

A. El-Osery, C. T. Abdallah, and M. Jamshidi, "Time Delay and Power Control in Spread Spectrum Wireless Networks", Proceedings of the 3rd IFAC Workshop on Time Delay Systems, pp. 182-187, Santa Fe, NM, Dec. 8-10 2001. [pdf] [ps]
Abstract: Delay in the computation of the signal-to-interference ratio in communication systems is unavoidable. In the the case of mobile communication, delay is a very critical problem due the fast variation of the communication channel and the need for effective, fast and accurate power control. In this paper we present our approach to dealing with the delay in mobile communication systems as well as our controller to achieve and maintain the desired signal quality. We will concentrate on the code division multiple access (CDMA) systems.

N. Herscovici, C. Christodoulu, A. El-Osery, C.T. Abdallah, "Distributed Power Control in CDMA Cellular Systems", IEEE Antennas and Propagation Magazine,Vol. 42, No. 4, pp.152-159, Aug. 2000. [pdf]
Abstract: In wireless cellular communication, it is essential to find effective means for power control of signals received from randomly dispersed users within one cell. Effective power control will heavily impact the system capacity. Distributed power control (DPC) is a natural choice for such purposes, because, unlike centralized power control, DPC does not require extensive computational power. Distributed power control should be able to adjust the power levels of each transmitted signal using only local measurements, so that, in a reasonable time, all users will maintain the desired signal-to-interference ratio. In this paper, we review different approaches for power control, focusing on CDMA systems. We also introduce state-space methods and linear quadratic power control (LQPC) to solve the power-control problem. A simulation environment was developed to compare LQPC with earlier approaches. The results show that LQPC is more effective, and is capable of computing the desired transmission power of each mobile station in fewer iterations, as well as being able to accommodate more users in the system.

S. Tarbouriech, C. T. Abdallah, and M. Ariola, "Bounded Control of Multiple-Delay Systems with Applications to ATM Networks", IEEE 2001 Conference on Decision and Control, pp. 2315-2320, Orlando, FL. [pdf] [ps]
Abstract: Congestion control in the Available Bit Rate (ABR) class of Asynchronous Transfer Mode (ATM) networks poses interesting challenges due to the presence of multiple-delays, magnitude and rate constraints on the inputs, amplitude limitation on the state, and additive disturbances. In this paper, we consider a fixed-structure controller for an ATM/ABR network, and solve a robust tracking control problem in which the target is a threshold on the queue level.

D. Hush, C. T. Abdallah, and B. Horne, "Model Following Using Multi-Layer Perceptrons", Proceedings on the 29th Conference on Decision and Control, pp. 2315-2320, Honolulu, HI, December 1990. [pdf]
Abstract: A model following controller is proposed for discrete nonlinear system using a recursive multi-layer perceptron (MLP). The MLP network contains dynamics and is able to minimize the error between the plant and a desired model in many cases.

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