The UI is developed in JAVA as an Android application running on the smart phone. The control of the radio (applications / waveforms to be loaded and executed, frequency setting, power level…) are to be performed via the touch screen. The different peripheral buttons of the phone could be reconfigured to serve different purposes (e.g. push-to-talk for a land mobile radio system). The smart phone microphone and speaker are to be used for audio-in and audio-out while the screen can be used for data presentation.
Signal Processing Elements
The signal processing functionalities of the application are distributed between the smart phone and the RF transceiver unit. The exact split is to be decided either at design time or at execution time based on the application packaging. It is envisaged however that most of the signal processing will be performed in the smart phone except for the frequency conversion, filtering and decimation/interleaving which would be executed in the RF transceiver FPGA. The connectivity between the RF transceiver and the Android phone can be performed via the USB port.
Note that the NordiaSoft team has developed a basic North American public safety P25 waveform, including the Vocoder, on a Samsung Galaxy S2. Therefore, it is very likely that the newer Samsung mobile phone will have the necessary processing capabilities for simple to medium complexity waveforms like the digital FM and Tetra waveforms.
RF Transceiver Unit
In the case of a Small Form Factor, Commercial Off the Shelf (COTS) RF units are considered. On the receive side, the RF transceiver unit will down-convert, filter and digitize the incoming RF signal. Further filtering and decimation can be accomplished in the on-board FPGA before data being sent to the smart phone, via the USB port, for further processing. On the transmit side, the smart phone will send the modulated waveform at an IF level to the RF Transceiver unit for up-conversion to the selected frequency and transmission over the air.
The desktop computer is used to load the SCA environment and applications on the Android smart phone. Once loaded, the computer can be disconnected leaving the smart phone and the RF transceiver to operate autonomously.
The desktop computer is also used as the development environment of the waveform applications. It hosts the SCA Architect development tool, the programming development environment, the cross compiler and ORB libraries.