Current communication systems can only receive and transmit data over specified standards and protocols. Although this is not an issue, it is a limitation. By using software-defined radio technology, smart phones would be able to communicate with various devices regardless of their protocol or standard. We will demonstrate this concept by communicating a sensor mote though the use of a universal software radio peripheral (USRP) that can support a wide range of frequencies.
GNU Radio was implemented as the software-defined radio for this project. GNU radio is a free open-source software development toolkit that provides a set of libraries for signal processing. It processes blocks to implement software radio using low-cost external RF hardware; in our case we used a USRP1. GNU Radio is mainly used for wireless communication research, but it is also used to implement real-world radio systems.
The Universal Software Radio Peripheral (USRP) was designed and created at Ettus Research LLC to be an inexpensive hardware device for software radio. The USRP was created with flexibility in mind, allowing developers to use various daughterboards to enable the USRP to connect over different frequency bands. The USRP consists of a signal processing motherboard, with programmable FPGA, supporting connections for up to two daughterboards. With two daughterboards, one can be used as a receiver and the other as a transmitter allowing for simultaneous reception and transmission.
A mote is the smallest unit of a wireless sensor network. It is comprised of a sensor, microcontroller, and transceiver chip. There are many types of motes, such as MICA2, MICAZ, and TelosB. Our project will focus on implementing the MICA2 mote. The MICA2 mote uses an Atmel ATMega 128L processor, a CC1000 radio transceiver, and a center frequency of 433/868/916 MHz.