International Journal of Engineering & Technology IJET-IJENS Vol: 11 No: 01 253 1110701-8282 IJET-IJENS © February 2011 IJENS I J E N S Nomadic Base Station (NBS): a Software Defined Radio (SDR) based Architecture for Capacity Enhancement in Mobile Communications Networks E. Adetiba 1 , V.O. Matthews 1 , S.A. Daramola 1 , , I. A. Samuel 1 , A. A. Awelewa 1 , M. E.U. Eleanya 2 . 1 Department of Electrical & Information Engineering, College of Science & Technology, Covenant University, Ota, Ogun State, Nigeria. 2 Chevron, 2,Chevron Drive, Lekki Peninsula, Lagos, Nigeria. Abstract - In this research work, the problem of congestion that leads to dropped calls at GSM cell sites and drastic reduction in network capacity is addressed. We designed a novel GSM base station architecture named Nomadic Base Station (NBS) which is based on Software Defined Radio (SDR) architecture and simulated the LNA for its receiver front-end. The NBS receiver LNA selects and amplifies GSM signal bursts operating at 900MHz and 1800MHz Radio Frequency Band. The later stages translate the Radio Frequency (RF) signal to Intermediate Frequency (IF) signal. This implements the SDR technology by digitizing the IF signal into bit streams that can be processed on generic Central Processing Unit (CPU) using custom written signal processing software. Keywords: Nomadic Base Station (NBS), GSM, LNA, MOSFET, CPU, SDR