Research and Investigation in Advanced Software-Defined Radio
Inclusive Dates: 07/01/03 - 12/31/04
Background - Software-Defined Radio (SDR) represents an evolving technology that has generated great interest in the wireless communications industry and should provide many opportunities for future contracts. Traditionally, radio system designs have incorporated mostly specialized hardware components, which has forced the development of a variety of different and incompatible wireless devices. SDR systems use software to implement functions previously performed by hardware components. Consequently, SDR systems can offer many benefits as compared to previous hardware-intensive designs such as multi-mode operation, the use of fewer discrete components, less-expensive product upgrades, over-the-air reconfiguration, increased interoperability, rapid time-to-market, improved spectrum efficiency, increased flexibility, and widespread connectivity.
Approach - To capture immediate contracts with the U.S. Government, this project focuses on identifying new and innovative techniques for using current technology to meet the military Joint Tactical Radio System (JTRS) requirements. The JTRS communications program, initiated in 2002 by the JTRS Joint Program Office, defines a family of software-programmable radios that will eventually replace a large number of legacy radios. Common modular software contained in JTRS devices will implement waveforms, protocols, encryption, and communications processes. This software is intended to fit within the JTRS Software Communications Architecture (SCA).
Accomplishments - The project team began the program by obtaining JTRS radio specifications, analyzing available hardware and software, and attending Object Management Group (OMG) Software Radio Domain Special Interest Group (DSIG) meetings. The project team has also acquired an open-source SCA-compliant Core Framework (CF) implemented in C++ for a Linux platform. The team developed an SDR test-bed to demonstrate radio communication using general-purpose processors. The demonstration system has a radio transmitter box that can connect to any standard laptop via universal serial bus (USB) and a radio receiver box that also connects to a standard laptop via USB. The system also uses Knoppix compact discs, which are run on the laptops and do not use the resident hard drives. All the signal-processing functions for both the transmitter and receiver are conducted by the general-purpose processor. The USB interface is used to both program the phase-locked loops (PLLs) and communicate with standard audio devices for raw complex signal input or output. This SDR test bed and demonstration system was presented at the Virginia Tech Symposium on Wireless Personal Communication.