White RHINO: a low-cost communications radar hardware platform

Includes bibliographical referencesThe Electromagnetic spectrum has always been a very expensive resource and hence, has not been accessible to everyone. Yet, it is under-utilized. The new Whitespace Technology standards provide an efficient way to use the spectrum. However, the concept of shared spectrum introduced by the Whitespace Technology promises to reduce the cost of accessing the spectrum by a huge margin. Also, because the standards utilize the television channels, the VHF and UHF frequencies facilitate wireless transmission over large distances. This has provided impetus to various application developers. Using Whitespace Technology for Communications Radar is one such novel application which has great benefits for the African scenario. Here, the population is scattered and infrastructure for navigation and tracking is inadequate. But, there is a shortage of low-cost commercially available hardware platforms tailored for the application. In order to boost Whitespace-based Communications Radar application development, the White RHINO(Reconfigurable Hardware Interface for computation and radio) hardware platform was developed. It aims to fill the gap of low-cost commercial hardware platforms available for Whitespace-based Communications Radar. Being a Communications Radar platform, the White RHINO had to be designed keeping the standards and regulating body norms as yardsticks. However, an achievable radar performance of the platform under various scenarios was also estimated. The White RHINO contains an FPGA (the Zynq7000 series) which has dual embedded ARM processing cores. For the wireless interface, it contains a field programmable RF transceiver and an RF frontend section. The platform contains wired networking capability of 2 Gbps. The platform also has 512 MB DDR3 and 128 Mbit NAND ash as onboard memory. Finally, it has USB host, SDIO and JTAG for programmability and temperature sensors for system monitoring. The manufactured boards were tested under lab environment. It was found that except a failure on the RF transceiver section (due to a PCB footprint error), other interfaces were functional. The White RHINO successfully runs both U-Boot and Linux as operating systems. The error and other minor bugs have been corrected for the next fabrication run. Also, the cost of the complete White RHINO system is less than 1000 USD which makes it a very powerful platform and yet, less expensive than most of the commercially available platforms designed for similar applications

Secrecy Energy Efficiency of MIMOME Wiretap Channels with Full-Duplex Jamming

Full-duplex (FD) jamming transceivers are recently shown to enhance the information security of wireless communication systems by simultaneously transmitting artificial noise (AN) while receiving information. In this work, we investigate if FD jamming can also improve the systems secrecy energy efficiency (SEE) in terms of securely communicated bits-per- Joule, when considering the additional power used for jamming and self-interference (SI) cancellation. Moreover, the degrading effect of the residual SI is also taken into account. In this regard, we formulate a set of SEE maximization problems for a FD multiple-input-multiple-output multiple-antenna eavesdropper (MIMOME) wiretap channel, considering both cases where exact or statistical channel state information (CSI) is available. Due to the intractable problem structure, we propose iterative solutions in each case with a proven convergence to a stationary point. Numerical simulations indicate only a marginal SEE gain, through the utilization of FD jamming, for a wide range of system conditions. However, when SI can efficiently be mitigated, the observed gain is considerable for scenarios with a small distance between the FD node and the eavesdropper, a high Signal-to-noise ratio (SNR), or for a bidirectional FD communication setup.Comment: IEEE Transactions on Communication

Homogeneous Test-bed for Cognitive Radio

In the current frequency allocation scheme, the radio spectrum is found to be heavily underutilized in time, frequency and space dimensions or any of their combination. To improve spectrum utilization, the unused contiguous or non-contiguous portion of the radio spectrum (spectrum hole) can be accessed opportunistically using cognitive radio technology provided it is interference free to the local users of the network. To reliably detect the spectrum holes, which is necessary to limit the interference, cognitive radio is required to have high time and frequency resolutions to detect radio technologies (e.g. GSM 900, 2.4 GHz WLAN) at the packet level in the transmitted channel to avoid misinterpretation of occupancy states in time and frequency. In addition, having high sensitivity and instantaneous dynamic range can enable cognitive radio to detect weak received signals and their detection in the presence of strong received signals. Besides these requirements, a large sensing bandwidth can increase the chances to find spectrum holes in multiple radio technologies concurrently. A chirp channel sounder receiver has been developed according to the aforementioned requirements with a bandwidth of 750 MHz to provide reliable detection of received signals in two frequency ranges; 1) 250 MHz to 1 GHz, 2) 2.2 GHz to 2.95 GHz. The developed receiver is capable of finding spectrum holes having a duration of 204.8 μs and a transmitted channel bandwidth up to 200 kHz. To explore the spectrum holes in the space dimensions, six chirp channel sounder receivers have been developed to form a homogeneous test-bed, which can be deployed and controlled independently. To experimentally validate the ability of the built receiver, short term spectrum occupancy measurements have been conducted to monitor 2.4 GHz WLAN traffic from a real wireless network to quantify the spectrum utilization and duration of spectrum holes in the time domain. It has been found that the radio spectrum is underutilized and empirical distribution of the duration of the spectrum hole can be modelled using lognormal and gamma distributions for prediction using a two state continuous time semi-Markov model. To experimentally validate the receiver’s capabilities in both the supported frequency ranges, long term spectrum occupancy measurements with 750 MHz sensing bandwidth have been performed and received signals have been detected at frame or packet level to quantify spectrum utilization. It has been found that the radio spectrum is highly underutilized at the measurement location and exhibits significant amount of spectrum holes in both time and frequency. To experimentally validate the functionalities of the homogeneous test-bed, short term spectrum occupancy have been performed to monitor 2.4 GHz WLAN traffic from a real wireless network. The experiment has been conducted using multiple receivers to quantify the amount of cooperation individual or multiple cognitive radio users can provide for reliable detection of spectrum holes in time, frequency and space. It has been found that the space dimension influences strongly the statistics of cooperation parameters

Wirelessly accessing instruments with standard GPIB/WLAN interfaces

The final objective of the project is to provide a Smartphone/GPIB interface. A small hardware and an Android application will allow the user to connect easily on a GPIB bus to send and receive data and commands. The device developed must offer a new and easier way to connect and get data from the instruments. The circuit must provide a transparent connection between the smartphone and the GPIB bus

Synchronous wearable wireless body sensor network composed of autonomous textile nodes

A novel, fully-autonomous, wearable, wireless sensor network is presented, where each flexible textile node performs cooperative synchronous acquisition and distributed event detection. Computationally efficient situational-awareness algorithms are implemented on the low-power microcontroller present on each flexible node. The detected events are wirelessly transmitted to a base station, directly, as well as forwarded by other on-body nodes. For each node, a dual-polarized textile patch antenna serves as a platform for the flexible electronic circuitry. Therefore, the system is particularly suitable for comfortable and unobtrusive integration into garments. In the meantime, polarization diversity can be exploited to improve the reliability and energy-efficiency of the wireless transmission. Extensive experiments in realistic conditions have demonstrated that this new autonomous, body-centric, textile-antenna, wireless sensor network is able to correctly detect different operating conditions of a firefighter during an intervention. By relying on four network nodes integrated into the protective garment, this functionality is implemented locally, on the body, and in real time. In addition, the received sensor data are reliably transferred to a central access point at the command post, for more detailed and more comprehensive real-time visualization. This information provides coordinators and commanders with situational awareness of the entire rescue operation. A statistical analysis of measured on-body node-to-node, as well as off-body person-to-person channels is included, confirming the reliability of the communication system

Throughput Performance Evaluation and Analysis of Unmodified Bluetooth Devices

The Air Force relies on the application of new technologies to support and execute its mission. As new technologies develop, the integration of that technology is studied to determine the costs and benefits it may provide to the war fighter. One such emergent technology is the Bluetooth wireless protocol, used to connect a small number of devices over a short distance. The short distance is a feature that makes using the protocol desirable. However short, there is still a vulnerability to interception. This research identifies ranges at which several commercially available Bluetooth devices are usable. Various combinations of both distance and orientation are varied to determine a 360 degree map of the Bluetooth antenna. The map identifies distances at which certain throughput thresholds are available. This research shows that baseline 1 mW Bluetooth antennas are capable of throughput levels of 100 kbps at over 40 meters, which is four times the minimum distance specified in the protocol standard. The 3Com PC card was the best performing PC card, capable of throughputs at or near 100 kbps out to 40 meters. The other PC Cards tested had similar performance. The Hawking USB dongle was the best USB antenna tested, achieving throughputs of over 200 kbps in three of the four orientation, and over 150 kbps at the fourth. The 3Com dongle was a close second, the Belkin dongle a distant third, while the DLink antenna was not able to achieve 100 kbps at any distance tested