Otimum Transmitter Power Control In Celiular Radio Systems

Abstract

In cellular radio systems, transmitter power controls aim at achieving acceptable carrier-to-interference (C/I) ratios in all active communication links. All of the existing power control schemes focus on single channel control, which could not guarantee optimal performance if applied to the whole system containing multiple channels. This paper presents a full optimization model for the transmitter power control problem which deals with all channels and cells in the system simultaneously. With the limitations of computational speed and data updating ability, our model, at this moment, may not be appropriate for real-time power control. Rather, our model provides a performance standard that various practical real-time power control methods can achieve. This is important information in the design of a practical real-time system. To solve the optimization model, we use the Lagrangian relaxation technique. Our computational result shows that it is possible to reduce the overall blocking probability by 20 – 50% over the existing power control schemes.

Résumé

Dans les systèmes radio cellulaire, le contrôle de la puissance transmise vise à maintenir un acceptable raport du signal sur interférence pour tout les canaux de communications. Tout les contrôle de puissance existants utilise le contrôle individuel de chaque canal, ce qui ne permet pas de garantir une performance optimale d'un réseau contenant de multiples canaux. Cet article présente un modèle pour l'optimisation du contrôle de la puissance transmise prenant en compte simulatenément tous les canaux et toutes les cellules présents dans le système. Du à la limitation de la puissance de calcul et de la vitesse de mise à jour des donnees, le modèle propose est peut-être pas complètement approprie pour le contrôle de la puissance transmise en temps réelle. Cependant ce modèle peu-être utilise comme référence pour l'évaluation de la performance de système de contrôle de la puissance transmise en temps réelle. Ceci une information importante pour le planification d'un réel systeme. Pour résoudre le problème de l'optimisation du modèle, une technique de relaxation lagrangienne. Les résultats montre qu'il est possible de réduire la probabilité de blocage de environ 20 – 50% en comparaison aux systemès existant.

Key Words:

• Transmitter power control problem
• Performance analysis

Mots-clés:

• problème du contrôle de la puissance transmise
• analyse de performance

Additional information

Notes on contributors

Sehun Kim

Sehun Kim received the B.S. degree in physics from Seoul National University, Seoul, Korea, in 1972, and the M.S. and Ph. D. degrees in operations research from Stanford University in 1978 and 1981, respectively. From 1981 to 1982 he worked at Systems Control, Incorporated. In 1982 he joined the Faculty of the Korea Advanced Institute of Science and Technology (KAIST), where he is currently a Professor of Management Science. He was a Visiting Professor at Arizona State University from 1986 to 1987. His research has been in the area of combinatotial and nonlinear optimization. Recently, he has been working on the application of optimization techniques to the design and analysis of computer and communication systems. He has published a number of papers in Mathematical Programming, Operations Research Letters, IEEE Trans. Veh. Technol, INFOR, and Intern. Journ. of Satellite Communications. He served as Editor of the Journal of Korean Operations Research Society from 1989 to 1991.

Dongwoo Kim

Dongwoo Kim received the B.A. degree in economics from Seoul National University, Seoul, Korea, in 1987, and the M.S. and Ph. D. degrees in management science from the Korea Advanced Institute of Science and Technology (KAIST) in 1989 and 1994, respectively. In 1994, he joined Shinsegi Telecommunication, Incorporated, Seoul, Korea and has been involved in the design, development and test of the CDMA cellular system for successful CDMA cellular deployment in Korea. His research interest is in the area of efficient power control, mobility and paging area management, and system design of the mobile radio system.