GNU Radio and OSSIE (Open-Source SCA (Software communication architecture) Implementation-Embedded) are two open source software toolkits for SDR (Software Defined Radio) developments, both of them can be supported by USRP (Universal Software Radio Peripheral). In order to compare the performance of these two toolkits, an FM receiver over GNU Radio and OSSIE are tested in my thesis, test results are showed in Chapter 4 and Chapter 5. Results showed that the FM receiver over GNU Radio has better performance, due to the OSSIE is lack of synchronization between USRP interface and the modulation /demodulation components. Based on this, the SISO (Single Input Single Output) communication system over GNU Radio is designed to transmit and receive sound or image files between two USRP equipped with RFX2400 transceiver at 2.45G frequency. Now, GNU Radio and OSSIE are widely used for academic research, but the future work based on GNU Radio and OSSIE can be designed to support MIMO, sensor network, and real time users etc.

As the complexity of software increases, so does the complexity of software testing. This challenge is especially true for modern military communications as radio functionality becomes more digital than analog. The Software Communications Architecture was introduced to manage the increased complexity of software radios. But the challenge of testing software radios still remains. A common methodology of software testing is the unit test. However, unit testing of software assumes that the software under test can be decomposed into its fundamental units of work. The intention of such decomposition is to simplify the problem of identifying the set of test cases needed to demonstrate correct behavior. In practice, large software efforts can rarely be decomposed in simple and obvious ways. In this paper, we introduce the fuzzing methodology of software testing as it applies to software radios. Fuzzing is a methodology that acts only on the inputs of a system and iteratively generates new test cases in order to identify points of failure in the system under test. The REDHAWK implementation of the Software Communications Architecture is employed as the system under test by a fuzzing framework called Peach. Fuzz testing of REDHAWK identified a software bug within the Core Framework, along with a systemic flaw that leaves the system in an invalid state and open to malicious use. It is recommended that a form of Fault Detection be integrated into REDHAWK for collocated processes at a minimum, and distributed processes at best, in order to provide a more fault tolerant system. / Master of Science

The Software Communications Architecture (SCA) specification defines a framework that allows modular software components to be developed and assembled to build larger radio applications. The specification allows for these components to be distributed among a set of computing hardware and to be connected by standard interfaces. This research aims to build a spatially distributed SCA application for the Open Source SCA Implementation: Embedded (OSSIE) implementation using low-cost Universal Software Radio Peripheral (USRP) hardware. The system collects signals from multiple spatially distributed collection devices and use those signals to compute precision estimates for the location of emitters using time difference of arrival (TDOA) computations. Several OSSIE components and tools are developed to support this research. Results are presented showing the capabilities of the geolocation system. / Master of Science

<p>For a long time radio devices have been constructed in hardware with a fixed functionality. This way of constructing radio devices is starting to change with the concept of Software Defined Radio (SDR) evolving. The SDR concept leads to more flexible and long lasting radio devices. In order to make the radio software more standardized and portable, the U.S. military has defined the Software Communication Architecture (SCA). Internal communication within the SCA is done by CORBA, which limit waveforms to be only distributed over CORBA-capable hardware. The U.S. military has defined the Modem Hardware Abstraction Layer(MHAL) to enable distribution over devices not supporting CORBA. This thesis presents an implementation of MHAL and an underlying transport mechanism based on Ethernet. The implementation is done for the OSSIE package. The implementation is evaluated both in terms of real-time and throughput performance. The results show that MHAL achieves good performance, in comparison to CORBA, and can greatly be used to distribute waveforms over both CORBA and non-CORBA capable devices.</p>

For a long time radio devices have been constructed in hardware with a fixed functionality. This way of constructing radio devices is starting to change with the concept of Software Defined Radio (SDR) evolving. The SDR concept leads to more flexible and long lasting radio devices. In order to make the radio software more standardized and portable, the U.S. military has defined the Software Communication Architecture (SCA). Internal communication within the SCA is done by CORBA, which limit waveforms to be only distributed over CORBA-capable hardware. The U.S. military has defined the Modem Hardware Abstraction Layer(MHAL) to enable distribution over devices not supporting CORBA. This thesis presents an implementation of MHAL and an underlying transport mechanism based on Ethernet. The implementation is done for the OSSIE package. The implementation is evaluated both in terms of real-time and throughput performance. The results show that MHAL achieves good performance, in comparison to CORBA, and can greatly be used to distribute waveforms over both CORBA and non-CORBA capable devices.

A very basic engineering tradeoff is performance versus flexibility and this design choice must be made when developing a software radio. Hardware devices such as General Purpose Processors (GPPs), Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs) and Application Specific Integrated Circuits (ASICs) all provide a designer with choices along the performance versus flexibility spectrum. The designer must choose a combination of GPP, DSP, FPGA and ASIC devices to balance the needs of performance versus flexibility. The Software Communications Architecture (SCA) is a specification for a software radio architecture produced by the Joint Program Executive Office (JPEO) Joint Tactical Radio System (JTRS). The 2.2 revision of the SCA only implies support for GPPs, with no specified support for additional devices such as FPGAs. However, FPGA integration within the scope of the SCA is still possible. The integration of an additional processing hardware device other than a GPP requires the ability to logically represent the device within the Core Framework. This representation is implemented within the OSSIE Core Framework, an open source implementation of the SCA. The representation requires the support of multiple implementations of signal processing components within the framework, a simple component deployment model, and the abstraction of the FPGA interactions into a software component. / Master of Science

The Software Communications Architecture (SCA) is a standard for software defined radios (SDR) designed in part to promote code reuse for long-term development. With the emergence of adaptive/cognitive radios, new SDRs that are capable of reconfiguration during runtime must be developed. One advantage of SDR development over conventional radio development can be ease of design if the proper rapid development tools are made available. This thesis explores tools designed to help realize the construction of reconfigurable systems while promoting code-reuse within the bounds of the SCA. Developing these tools requires an understanding of the SCA as well as the Open Source SCA Implementation Embedded (OSSIE) for which they are developed. The use of CORBA to link together modularized components is also discussed. Finally, several simulations are conducted in order to approximate the amount of overhead resulting from the use of the reconfiguration tool developed (the "Connect Tool"). / Master of Science

The idea of wireless distributed computing (WDC) is rapidly gaining recognition owing to its promising potential in military, public safety and commercial applications. This concept basically entails distributing a computationally intensive task that one radio device is assigned, among its neighboring peer radio devices. The added processing power of multiple radios can be harnessed to significantly reduce the time consumed in obtaining the results of the original complex task. Since the idea of wireless distributed computing depends on a radio device forming a network with its peers, it is imperative and necessary to have a medium access control (MAC) protocol for such networks which is capable of scheduling channel access by multiple radios in the network, ensuring reliable data transfer, incorporating rate adaptation as well as handling link failures. The thesis presented here elaborates the design and implementation of such a MAC protocol for WDC employed in a practical network of radio devices configurable through software. It also brings to light the design and implementation constraints and challenges faced in this endeavor and puts forward viable solutions. / Master of Science