A Mobile Platform Using Software Defined Radios For Wireless Communication Systems Experimentation

A distinctive feature of wireless communication systems is implied by the fact that there is no physical connection between the transmitter and its corresponding receiver, which enables user mobility. However, experimenting with wireless communication systems is mostly done in the lab, where transmitters and receivers are setup on benches, in stationary settings. This prevents students from experiencing fading and other propagation effects associated with mobile wireless channels. This paper describes a mobile platform for wireless communication experimentation that enables students to run experiments beyond the confines of a traditional lab, in realistic settings that cover indoor and outdoor scenarios with both fixed and mobile propagation characteristics. The platform presented consists of a Universal Software Radio Peripheral (USRP) from National Instruments to implement the transmitter, an affordable RTL-SDR USB dongle to implement the receiver, a laptop computer used to program the SDR boards, and equipment for visualizing radio signal characteristics such as a portable spectrum analyzer or oscilloscope. This choice results in a moderate overall cost for the radio hardware required by the platform, which can be easily programmed using open source software such as GNU Radio as well as software packages like Matlab or LabView. For experimentation in wireless scenarios with low mobility (both indoors and outdoors, corresponding to walking speeds) the transmitter and receiver may be placed on push carts, while for higher mobility they may be placed on university owned golf carts moving at faster speeds on the designated campus routes. Furthermore, mobile transmitters and receivers may also be placed in cars driving on the campus streets and through the university parking lots/garages to enable experiments simulating vehicle to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications

A Primer on Software Defined Radios

The commercial success of cellular phone systems during the late 1980s and early 1990 years heralded the wireless revolution that became apparent at the turn of the 21st century and has led the modern society to a highly interconnected world where ubiquitous connectivity and mobility are enabled by powerful wireless terminals. Software defined radio (SDR) technology has played a major role in accelerating the pace at which wireless capabilities have advanced, in particular over the past 15 years, and SDRs are now at the core of modern wireless communication systems. In this paper we give an overview of SDRs that includes a discussion of drivers and technologies that have contributed to their continuous advancement, and presents the theory needed to understand the architecture and operation of current SDRs. We also review the choices for SDR platforms and the programming options that are currently available for SDR research, development, and teaching, and present case studies illustrating SDR use. Our hope is that the paper will be useful as a reference to wireless researchers and developers working in the industry or in academic settings on further advancing and refining the capabilities of wireless systems

Co-channel DBPSK source separation

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2007.Includes bibliographical references (leaves 51-53).This thesis presents a Differential Binary Phase Shift Key (DBPSK) source separation system implemented with the GNU Software Defined Radio (SDR) platform and interfaced with the existing MIT community Radio Frequency Identification (RFID) system. Source separation, well studied in the theoretical signal processing setting, presents an opportunity to achieve higher throughput in a practical SDR deployment. While much research has centered around the design of complex multi-input-multi-output (MIMO) and code division multiple access (CDMA) systems, single antenna source separation presents a simple alternative that is suitable in settings such as RFID where sources are naturally synchronized. Motivated by the analysis of physical channel properties with GNU SDR, this thesis documents the complete design process from the physical layer to the application layer and presents a realization of a co-channel DBPSK source separating technique. The result is an intelligent RFID source-separating reader that is capable of decoding multiple "dumb" cards.by Grace R. Woo.S.M

Spatial Identification of Passive Radio Frequency Identification Tags Using Software Defined Radios

This research seeks to utilize a software defined radio for the detection and spatial identification of radio frequency identification tags. A software defined radio (SDR) is a hardware platform that provides the ability to broadcast and receive across multiple bands of the radio frequency (RF) spectrum, depending on the RF front end and software profile loaded on it. The focus of the research will be on the spatial identification (SID) of passive radio frequency identification tags (RFID). The research is applicable to many areas of day-to-day operations both within the DoD and industry. Flight line safety tracking of equipment and personnel, as well as perimeter defense, are two areas that may benefit from this technology. One dual-purpose, civilian and military, application would be the tracking and locating of inventory within a warehouse. The research developed and implemented a SID process, and proved its suitability to quickly identify and locate target tags within range. A profile of the system\u27s capabilities and limitations in a laboratory environment was developed, including range, sensitivity, and accuracy