CDMA系統(tǒng)中的自適應(yīng)反向閉環(huán)功率控制
ADAPTIVE CLOSE-LOOP POWER CONTROL ON THE REVERSE LINK FOR CDMA SYSTEM
-
摘要: 在碼分多址(CDMA)移動(dòng)通信系統(tǒng)中，反向鏈路功率控制對(duì)克服遠(yuǎn)近效應(yīng)和增加系統(tǒng)容量是非常重要的。本文提出了一種基于改進(jìn)的神經(jīng)網(wǎng)絡(luò)(MNN)的自適應(yīng)閉環(huán)功率控制算法，該方法平滑了移動(dòng)信道衰落的影響，使基站接收到的小區(qū)中所有用戶的信號(hào)功率相等。仿真結(jié)果表明，由于神經(jīng)網(wǎng)絡(luò)能夠較好地識(shí)別反向鏈路的時(shí)變特性，MNN功率控制方法比傳統(tǒng)的固定步長(zhǎng)功率控制方法取得了更好的控制性能和系統(tǒng)容量。
-
關(guān)鍵詞:
- 碼分多址; 功率控制; 遠(yuǎn)近效應(yīng); 多徑衰落; 中斷率
Abstract: Power control is of paramount important to combat the near-far problem and achieve high system capacity in CDMA cellular system. In this paper, a Modified Neural Network (MNN) based power controller is proposed to smoothen out the fast fading and keep the received signal power from each user constant at the base station. Simulation results show that MNN power controller achieves better control performance and system capacity than fixedstep controller due to the inherent ability of MNN to identify the fast time-varying characteristic of inverse channel. -
Savo Glisic, Branka Vucetic, Spread Spectrum CDMA Systems for Wireless Communications,Dedham, MA, Artech House, Inc., 1997, Ch.5, 211-262.[2]R. C. V. Macario, Cellular Radio Principles and Design, Great Britain, Antony Rowe Ltd, Second Edition, 1997, Ch2, 38-59.[3]Po-Pong Chang, Bor-chin Wang, Adaptive fuzzy power control for CDMA mobile systems, IEEE Trans. on Vehicular Technology, 1996, 45(2), 225-236.[4]Kaveh Pahlavan, A. H. Levesque, Wireless Information Networks, USA, John Wley Sons Inc.,1995.[5]Y. P. Zhang, Y. Hwang, Measurements and Statistical Modeling of 900 MHz Radio Propagation Channels for Microcelluar and Personal Communications in Tunnels, Wireless Personal Communications, Netherlands: Kluwer Academic Publishers, 1998, 27-39.[6]W. C. Jakes(Ed.), Microwave Mobile Communications, New York, NY, Wiley, 1974.[7]X. M. Gao, X. Z. Gao, J. M. A.Trankanen,S.J. Ovaska, Power control for mobile DS/CDMA system using ELMAN neural network controller, in Proc. IEEE 47th Vehicular Technology Conference, Phoenix, Arizona, USA, 1997, 750-754. -
計(jì)量
- 文章訪問(wèn)數(shù): 2564
- HTML全文瀏覽量: 111
- PDF下載量: 394
- 被引次數(shù): 0
下載:
