The implementation of TETRA using GNU Radio and USRP

TETRA (Terrestrial Trunked Radio) is a digital trunking communication standard which is recommended by ETSI (European Telecommunications Standards Institute) and has been widely used in the world. It has been used in many areas such as underground, fire protection, police system. SDR (Software Defined Radio) is a technology which just changes the software without changing the hardware to implement different communication systems. The combination of GNU Radio and USRP is such a high speed, cost effective SDR platform. GNU Radio is an open source software project which can support SDR. And USRP (Universal Software Radio Peripheral) is the hardware which is the most important hardware partner of GNU Radio. This paper focuses on using GNU Radio and USRP to implement the pi/4 DQPSK modulation and demodulation technology, the main modulation method in TETRA I. Besides, transmit and receive the modulated signal in the real wireless channel.