GSM BTS implementation using open software and hardware / Mohd Khairul Izwan Che Soh

This thesis highlights the current achievements of open-source community developers in the area of building GSM-enabled communication in terms of its hardware and software. The main objective of this thesis is to build a GSM telephone network at much lower complexity and cost as compared to conventional GSM network. The combination of the ubiquitous GSM air interface with VoIP backhaul can form a new type of cellular network that could be deployed and operated at substantially lower cost than existing technologies in the developing world. This research is carried out by OpenBTS running in place of USRP that implements Um maps the GSM traffic and control signals to Asterisk to simulate communication through voice calls and SMS between GSM handsets. The end product is a novel cellular network that can be installed and operated at about ten percent the cost of current technologies, but is compatible with most of the handsets that are already in the market today. Potential applications include rural or village telephony and text messaging, cellular coverage in remote areas, rapidly deployable emergency communications, network emulation and handset testing, law enforcement and security operations. This study has given an account of Software Defined Radio and the reasons for the widespread use of open source software and hardware. Essentially, these findings enhance the understanding of the GSM network. This study also serves as a base for future studies of Software Defined Radio. The methods used for this research may be applied to another location that needs GSM communication elsewhere in the world. There are several improvements that can be made for future work such as adding power amplifier and better antenna to extend the coverage, adding an FXO / FXS card to host computer for PSTN connectivity, using an external clock generator for better stability and performing real world implementation in rural area.