Standard APCO25 Physical Layer of the Radio Transmission Chain

Abstract: Professional Mobile Radio (PMR) also known as Private Mobile Radio or Land Mobile Radio (LMR) are radio systems conceived for public safety or professional event organizers. They are designed to provide a reliable and robust communication system independent from conventional public networks. In France, for instance, the national police is equipped with a PMR network, namely ACROPOL, that blankets the entire country and allows both voice and low data rate services. The object of this thesis is the North-American standard Project P25. It is a standard defined by the Telecommunications Industry Association (TIA) and is currently used by many radio communication systems in North-America. This report presents the results of a Matlab/C simulation designed to provide performances information on P25 physical layer. This knowledge is exploited to verify that the standard requirements are met. The final purpose of this thesis is the integration of Project 25 Layer 1 on a real radio platform. Thus, this report gauges the performances of all the modulators defined in the TIA standard for both Project 25 phase 1 and phase 2. Several tests are presented, they were realized in different conditions, that is with different channel models, propagation models as well as with or without any fading, in static and dynamic conditions. From this simulation, the Bit Error Rates vs Eb/N0 results have been extracted and are presented. The complete Forward Error Correction part has also been implemented and the correction capability of all the encoders and decoders has been verified, yielding the BER vs Eb/N0 plots. The resistance to an interferer has been evaluated, in several cases, with an interferer in the same channel or in an adjacent channel. The second part of this report presents the integration of the physical layer on a radio device. This was done to validate that both physical and MAC layers were compliant to the standard. This has been realized by interfacing the radio platform with Matlab via an Ethernet link and using UDP protocol.  Furthermore, at the end of the thesis some conclusions are drawn and future possible studies are detailed.