Universal Software Defined Radio Research Articles

Proactive Anti-Eavesdropping With Trap Deployment in Wireless Networks

Due to the open nature of the wireless medium, wireless communications are especially vulnerable to eavesdropping attacks. This article designs a new wireless communication system to deal with eavesdropping attacks. The proposed system can enable a legitimate receiver to get desired messages and meanwhile an eavesdropper to hear “fake” but meaningful messages by combining confidentiality and deception, thereby confusing the eavesdropper and achieving additional concealment that further protects exchanged messages. Towards this goal, we propose techniques that can conceal exchanged messages by utilizing wireless channel characteristics between the transmitter and the receiver, as well as techniques that can attract an eavesdropper to gradually approach a trap region, where the eavesdropper can get fake messages. We also provide both theoretical and empirical analysis of the established secure channel between the transmitter and the receiver. We develop a prototype system using Universal Software Defined Radio Peripherals (USRPs). Experimental results show that an eavesdropper at a trap location can receive fake information with a bit error rate (BER) close to 0, and the transmitter with multiple antennas can successfully deploy a trap area.

Signal Entanglement Based Pinpoint Waveforming for Location-Restricted Service Access Control

We propose a novel wireless technique named pinpoint waveforming to achieve the location-restricted service access control, i.e., providing wireless services to users at eligible locations only. The proposed system is inspired by the fact that when two identical wireless signals arrive at a receiver simultaneously, they will constructively interfere with each other to form a boosted signal whose amplitude is twice of that of an individual signal. As such, the location-restricted service access control can be achieved through transmitting at a weak power, so that receivers at undesired locations (where the constructive interference vanishes), will experience a low signal-to-noise ratio (SNR), and hence a high bit error rate that retards the correct decoding of received messages. At the desired location (where the constructive interference happens), the receiver obtains a boosted SNR that enables the correct message decoding. To solve the difficulty of determining an appropriate transmit power, we propose to entangle the original transmit signals with jamming signals of opposite phase. The jamming signals can significantly reduce the SNR at the undesired receivers but cancel each other at the desired receiver to cause no impact. With the jamming entanglement, the transmit power can be any value specified by the system administrator. To enable the jamming entanglement, we create the channel calibration technique that allows the synchronization of transmit signals at the desired location. We develop a prototype system using the Universal Software Defined Radio Peripherals (USRPs). The evaluation results show that the receiver at the desired location obtains a throughput ranging between 0.9 and 0.93, whereas an eavesdropper that is 0.3 meter away from a desired location has a throughput approximately equal to 0.

A Multichannel Receiver of the Experimental FM Based Passive Radar Using Software Defined Radio Technology

Abstract In this paper we present results of research on multichannel receiver using Software Defined Radio technology. This receiver is a part of the experimental FM based passive radar being designed. The hardware platform of the receiver consists of the Universal Software Defined Radio Peripheral devices. In the paper we propose modifications of the USRP’s FPGA configuration and GNU Radio code. These modifications allow for developing six/nine synchronous input channel receiver based on two/tree USRPs respectively. Issues of synchronization of separate USRP devices by assuring synchronous sampling were presented. We also propose the solution of the problem of the alignment of the data streams being sent from USRP devices via USB to the PC host.