Correlator implementation for orthogonal CSS used in an ultrasonic LPS

This paper presents a new architecture for the correlation of orthogonal complementary sets of sequences (OCSS) and their performance in an ultrasonic local positioning system (U-LPS). OCSS are sets of sequences whose addition of correlation functions has ideal properties, that makes interference-free code-division multiple access (CDMA) possible. They can be used to encode the signals emitted by a CDMA based U-LPS, enhancing the performance of such systems in terms of immunity against noise, multipath propagation, and near-far effect. Also, the orthogonality of the codes offers an operation resistance to multiaccess interference, which endows the U-LPS with the capability of simultaneous emission from different beacons. On the other hand, the detection of OCSS codes can be performed by means of efficient algorithms. This paper presents an optimization of previous proposals allowing the simultaneous correlation of OCSS by using fewer operations and memory elements. Furthermore, the hardware implementation of the proposed optimization is also addressed, and an U-LPS based on this proposal is presented.Fil: Peréz Rubio, M. Carmen. Universidad de Alcalá; EspañaFil: Sanz Serrano, Rebeca. Universidad de Alcalá; EspañaFil: Ureña Ureña, Jesús. Universidad de Alcalá; EspañaFil: Hernández Alonso, Álvaro. Universidad de Alcalá; EspañaFil: de Marziani, Carlos Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Álvarez Franco, Fernando J.. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ingeniería - Sede Comodoro; Argentin

Chip and Signature Interleaving in DS CDMA Systems

Siirretty Doriast

Advanced digital SAR processing study

A highly programmable, land based, real time synthetic aperture radar (SAR) processor requiring a processed pixel rate of 2.75 MHz or more in a four look system was designed. Variations in range and azimuth compression, number of looks, range swath, range migration and SR mode were specified. Alternative range and azimuth processing algorithms were examined in conjunction with projected integrated circuit, digital architecture, and software technologies. The advaced digital SAR processor (ADSP) employs an FFT convolver algorithm for both range and azimuth processing in a parallel architecture configuration. Algorithm performace comparisons, design system design, implementation tradeoffs and the results of a supporting survey of integrated circuit and digital architecture technologies are reported. Cost tradeoffs and projections with alternate implementation plans are presented

Pseudo-Random Codes for Single-Mode and Simultaneous Multi-Mode Operation in Ultrasonic Imaging Systems

Conventional pulse-echo imaging systems used in ultrasonics can become limited in average transmit power by transmitter, transducer, and medium peak-power limitations. In addition, imaging systems which use multi-element arrays are limited in speed by the necessity to transmit sequentially when scanning in more than one direction in order to avoid interfering echoes. A new system is studied which can overcome both the speed and power limitations by using correlation receivers and pseudo-random transmit codes. First, the performance of several single-mode correlation systems are compared to conventional pulse-echo systems in the presence of clutter and moving targets. The system which uses special pseudo-random codes called Golay codes is shown to provide the best overall performance. A multi-mode correlation system is then studied which images in many different modes (e.g. scan directions) simultaneously. This multi-mode system is studied under the effects of moving targets, clutter and background receiver noise. A comparison with the operation of Conventional sequentially-scanned phased array systems is made under a variety of signal-to-noise ratio (SNR) conditions and operating speeds to determine the optimal type of imaging system. Results indicate that under many conditions, a simultaneous multi-mode system can provide improved SNR and/or speed over conventional sequential multi-mode systems. The multi-mode system which uses Golay codes is shown to provide the best overall performanc

A Survey on FPGA-Based Sensor Systems: Towards Intelligent and Reconfigurable Low-Power Sensors for Computer Vision, Control and Signal Processing

The current trend in the evolution of sensor systems seeks ways to provide more accuracy and resolution, while at the same time decreasing the size and power consumption. The use of Field Programmable Gate Arrays (FPGAs) provides specific reprogrammable hardware technology that can be properly exploited to obtain a reconfigurable sensor system. This adaptation capability enables the implementation of complex applications using the partial reconfigurability at a very low-power consumption. For highly demanding tasks FPGAs have been favored due to the high efficiency provided by their architectural flexibility (parallelism, on-chip memory, etc.), reconfigurability and superb performance in the development of algorithms. FPGAs have improved the performance of sensor systems and have triggered a clear increase in their use in new fields of application. A new generation of smarter, reconfigurable and lower power consumption sensors is being developed in Spain based on FPGAs. In this paper, a review of these developments is presented, describing as well the FPGA technologies employed by the different research groups and providing an overview of future research within this field.The research leading to these results has received funding from the Spanish Government and European FEDER funds (DPI2012-32390), the Valencia Regional Government (PROMETEO/2013/085) and the University of Alicante (GRE12-17)

Spread spectrum-based video watermarking algorithms for copyright protection

Merged with duplicate record 10026.1/2263 on 14.03.2017 by CS (TIS)Digital technologies know an unprecedented expansion in the last years. The consumer can now benefit from hardware and software which was considered state-of-the-art several years ago. The advantages offered by the digital technologies are major but the same digital technology opens the door for unlimited piracy. Copying an analogue VCR tape was certainly possible and relatively easy, in spite of various forms of protection, but due to the analogue environment, the subsequent copies had an inherent loss in quality. This was a natural way of limiting the multiple copying of a video material. With digital technology, this barrier disappears, being possible to make as many copies as desired, without any loss in quality whatsoever. Digital watermarking is one of the best available tools for fighting this threat. The aim of the present work was to develop a digital watermarking system compliant with the recommendations drawn by the EBU, for video broadcast monitoring. Since the watermark can be inserted in either spatial domain or transform domain, this aspect was investigated and led to the conclusion that wavelet transform is one of the best solutions available. Since watermarking is not an easy task, especially considering the robustness under various attacks several techniques were employed in order to increase the capacity/robustness of the system: spread-spectrum and modulation techniques to cast the watermark, powerful error correction to protect the mark, human visual models to insert a robust mark and to ensure its invisibility. The combination of these methods led to a major improvement, but yet the system wasn't robust to several important geometrical attacks. In order to achieve this last milestone, the system uses two distinct watermarks: a spatial domain reference watermark and the main watermark embedded in the wavelet domain. By using this reference watermark and techniques specific to image registration, the system is able to determine the parameters of the attack and revert it. Once the attack was reverted, the main watermark is recovered. The final result is a high capacity, blind DWr-based video watermarking system, robust to a wide range of attacks.BBC Research & Developmen

Simulation framework for multigigabit applications at 60 GHz

This dissertation describes the implementation of a OFDM-based simulation framework for multigigabit applications at 60 GHz band over indoor multipath fading channels. The main goal of the framework is to provide a modular simulation tool designed for high data rate application in order to be easily adapted to a speci c standard or technology, such as 5G. The performance of OFDM using mmWave signals is severely a ected by non-linearities of the RF front-ends. This work analyses the impact of RF impairments in an OFDM system over multipath fading channels at 60 GHz using the proposed simulation framework. The impact of those impairments is evaluated through the metrics of BER, CFR, operation range and PSNR for residential and kiosk scenarios, suggested by the standard for LOS and NLOS. The presented framework allows the employment of 16 QAM or 64 QAM modulation scheme, and the length of the cyclic pre x extension is also con gurable. In order to simulate a realistic multipath fading channel, the proposed framework allows the insertion of a channel impulse response de ned by the user. The channel estimation can be performed either using pilot subcarriers or Golay sequence as channel estimation sequences. Independently of the channel estimation technique selected, frequency domain equalization is available through ZF approach or MMSE. The simulation framework also allows channel coding techniques in order to provide a more robustness transmission and to improve the link budget

Synchronization Performance in DVB-T2 system

The Digital Video Broadcasting (DVB) project has developed digital broadcasting system specifications which have been adapted worldwide. The family of DVB standards includes DVB-S for satellite, DVB-C for cable and DVB-T for terrestrial system. This DVB-T system has proven its capability and thus accepted as the standard for terrestrial system in most countries. DVB-T2 is the enhancement of DVB-T that will overcome the shortcomings of the previous standard and provide additional features. This thesis concentrates on synchronization performance in DVB-T2 systems. Synchronization is the most important task that the receiver has to perform in the beginning of its reception of the signal. DVB-T2 uses Orthogonal Frequency Division Multiplexing (OFDM) modulation method and has a special symbol, named P1 symbol, for performing initial synchronization tasks. This symbol is also used for detecting DVB-T2 signal, meaning that, if the receiver can detect the P1 symbol, then it can conclude that the channel contains DVB-T2 signal. Moreover, P1 symbol also transmits basic transmission parameters that the receiver needs in the first place in order to proceed for further processing. In this work, the DVB-T2 system model has been implemented including the P1 symbol and the performance of synchronization by P1 symbol has been analyzed extensively by simulations in different channel conditions. P1 symbol deals with the synchronization issues before performing Fast Fourier Transform (FFT). Therefore, P1 symbol based methods can achieve coarse timing synchronization and fine frequency synchronization. Also the detecting and decoding probabilities based on P1 symbol in different channels are presented in this thesis. /Kir0

Synchronization Performance in DVB-T2 system

The Digital Video Broadcasting (DVB) project has developed digital broadcasting system specifications which have been adapted worldwide. The family of DVB standards includes DVB-S for satellite, DVB-C for cable and DVB-T for terrestrial system. This DVB-T system has proven its capability and thus accepted as the standard for terrestrial system in most countries. DVB-T2 is the enhancement of DVB-T that will overcome the shortcomings of the previous standard and provide additional features. This thesis concentrates on synchronization performance in DVB-T2 systems. Synchronization is the most important task that the receiver has to perform in the beginning of its reception of the signal. DVB-T2 uses Orthogonal Frequency Division Multiplexing (OFDM) modulation method and has a special symbol, named P1 symbol, for performing initial synchronization tasks. This symbol is also used for detecting DVB-T2 signal, meaning that, if the receiver can detect the P1 symbol, then it can conclude that the channel contains DVB-T2 signal. Moreover, P1 symbol also transmits basic transmission parameters that the receiver needs in the first place in order to proceed for further processing. In this work, the DVB-T2 system model has been implemented including the P1 symbol and the performance of synchronization by P1 symbol has been analyzed extensively by simulations in different channel conditions. P1 symbol deals with the synchronization issues before performing Fast Fourier Transform (FFT). Therefore, P1 symbol based methods can achieve coarse timing synchronization and fine frequency synchronization. Also the detecting and decoding probabilities based on P1 symbol in different channels are presented in this thesis. /Kir0