Design and Implementation of SDR-Based GSM Mobile BTS for Remote and Disaster Affected Areas

This paper presents design and implementation of SDR-based GSM mobile Base Transceiver Station (BTS) for remote and disaster-affected areas. The system consists of Nuand bladeRF x115 as the SDR, Raspberry Pi 3 as the main processing unit, GSM900 amplifier, dual band GSM900 patch antenna for uplink and downlink communication, and the power supply which consists of LiPo 14.8V 5200 mAh battery and KIS3R33S 5V voltage regulator module. Beside hardware components, the system uses YateBTS as the BTS software. The system is tested by sending SMS and voice calling. The received power was also measured at certain range from the BTS. The voice call and SMS were succesfully performed within range of 90 meters with minimum received power of −105dBm. The dual band GSM patch antenna was also fabricated on 1.6mm thick FR4 epoxy substrate with dimension of $85\mathbf{mm}\times 85\mathbf{mm}$. The simulation result shows that the return loss value of the dual band GSM patch antenna is −34,22dB and −36,99dB at frequency of 907MHz (uplink) and 953MHz (downlink), respectively. Whilst the measured result shows that the return loss value is −28,83dB and −23,22dB at frequency of 915MHz (uplink) and 960MHz (downlink), respectively.