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Enhancement of Digital Radio Features-An Approach towards Generation of Waveforms for SDR  [PDF]
T.Sailaja rani,Raja Sekhar
International Journal of Computer Science and Communication Networks , 2012,
Abstract: A Software defined radio (SDR) defines the transmitted waveforms and demodulates the received waveforms. SDR is an interdisciplinary technology involving a combination of hardware and software technologies where some or all of the physical layer functionality are programmable. Re-configurable platform of SDR device hosts several software components to provide users with functional services. A user can load number of “Software Defined Personalities” on to an SDR. A personality includes RF band, channel set, air interface waveform and related functions that are completely software defined. This paper aims towards the Study of existing Digital Radio features and implementation of various stages of the Digital radio in terms of Software platform by generation of waveforms for SDR.
Study on the Influence of RMB’s Entry into SDR on the Interest Rate of SDR  [PDF]
Danyi Zhao
American Journal of Industrial and Business Management (AJIBM) , 2019, DOI: 10.4236/ajibm.2019.92018
Abstract: On October 1, 2016, with the approval of the International Monetary Fund, the RMB officially joined the SDR currency basket, which not only recognized the international status of RMB, but also injected new vitality into the development of the world economy. SDR interest rate is an important part of SDR valuation and pricing. Based on the background of RMB entering the SDR currency basket, this paper divides the study period into three parts to analyse the impact of RMB enter the basket on the SDR interest rate: a complete review period before the RMB included; the IMF announced that it will accept the RMB but not yet; and the RMB is officially “add to the basket”. The results of the study show that RMB’s participation in the SDR basket significantly improves the SDR interest rate level, helps to improve the stability of the SDR interest rate and the representation of the SDR interest rate to the global economy, and is expected to help build a new order in the international monetary system.
SMSE Waveform Design Using Soft Decision Selection and Dynamic Assignment of Subcarrier Modulation Order and Power  [cached]
Eric Like,Michael Temple,Zhiqiang Wu
Journal of Communications , 2009, DOI: 10.4304/jcm.4.10.766-780
Abstract: Spectrally Modulated, Spectrally Encoded (SMSE) waveforms have demonstrated considerable practical utility and remain a viable alternative for Cognitive Radio (CR) -based Software Defined Radio (SDR) applications. As demonstrated in this paper, this utility is greatly enhanced when soft decision selection and dynamic assignment of SMSE design parameters is incorporated. This paper provides the analytical development for optimizing SMSE performance in a coexistent environment containing Primary User (PU) signals. Optimization is performed by exploiting statistical knowledge of PU spectral and temporal behavior, and independently selecting SMSE intra-symbol subcarrier power and modulation order using soft decision criteria. It is shown that SMSE system throughput can be maximized while adhering to SMSE and PU bit error rate (BER) constraints while limiting mutual coexistent interference to manageable levels. For proof-of-concept demonstration, simulation results are presented for SMSE coexistent scenarios containing DSSS and OFDM-based 802.11a PU signals. A sensitivity analysis is also provided to show performance changes resulting from variation in SMSE waveform update latency and update interval. Relative to a spectrally-only adapted waveform, the spectrally-temporally adapted SMSE waveform provides significant performance improvement. Maximum improvement is achieved using statistic-based prediction of PU channel temporal conditions and the appropriate SMSE waveform design update interval.
Multiband Antennas for SDR Applications  [PDF]
E. Surducan,V. Surducan,D. Iancu,J. Glossner
International Journal of Digital Multimedia Broadcasting , 2009, DOI: 10.1155/2009/460143
Abstract: We present multiband antennas configurations for SDR applications. Using a composite folded dipole structure as starting point, we derived more complex antenna configurations to support multiple communication protocols for mobile application with linear and circular polarizations. Prototypes as single antenna with circular polarization, tunable single antenna with PIN diode and MIMO systems with three and four antennas, all derivatives of the same basic structure, were produced in an iterative fashion until the desired parameters were achieved. These antennas are suitable for microstrip circuit realizations and can be included in the printed circuit board (PCB) of the device, or used as stand alone. The shapes and measurement results are presented throughout the paper. From the illustrated graphs it can be seen that the stand-alone antennas exhibit positive gain for all the frequency bands of interest while the separation between antennas, for the multiple-input multiple-output (MIMO) case, is better than 15 dB.
Black-hole concept of a point-like nucleus with supercritical charge  [PDF]
A. E. Shabad
Physics , 2005, DOI: 10.1088/0305-4470/38/33/014
Abstract: The Dirac equation for an electron in the central Coulomb field of a point-like nucleus with the charge greater than 137 is considered. This singular problem, to which the fall-down onto the centre is inherent, is addressed using a new approach, based on a black-hole concept of the singular centre and capable of producing cut-off-free results. To this end the Dirac equation is presented as a generalized eigenvalue boundary problem of a self-adjoint operator. The eigenfunctions make complete sets, orthogonal with a singular measure, and describe particles, asymptotically free and delta-function-normalizable both at infinity and near the singular centre $r=0$. The barrier transmission coefficient for these particles responsible for the effects of electron absorption and spontaneous electron-positron pair production is found analytically as a function of electron energy and charge of the nucleus. The singular threshold behaviour of the corresponding amplitudes substitutes for the resonance behaviour, typical of the conventional theory, which appeals to a finite-size nucleus.
Exploiting Redundancy in an OFDM SDR Receiver  [PDF]
Tomas Palenik,Peter Farkas
International Journal of Digital Multimedia Broadcasting , 2009, DOI: 10.1155/2009/194148
Abstract: Common OFDM system contains redundancy necessary to mitigate interblock interference and allows computationally effective single-tap frequency domain equalization in receiver. Assuming the system implements an outer error correcting code and channel state information is available in the receiver, we show that it is possible to understand the cyclic prefix insertion as a weak inner ECC encoding and exploit the introduced redundancy to slightly improve error performance of such a system. In this paper, an easy way to implement modification to an existing SDR OFDM receiver is presented. This modification enables the utilization of prefix redundancy, while preserving full compatibility with existing OFDM-based communication standards.
Power consumption reduction in a SDR based wireless communication system using partial reconfigurable FPGA  [PDF]
Neenu Joseph,P Nirmal Kumar
International Journal of VLSI Design & Communication Systems , 2012,
Abstract: The increase in the consumer demand and the exponential growth for wireless systems, which enables consumer to communicate in any place by means of information, has in turn led to the emergence of manyportable wireless communication products. The present research works primarily targets to integrate asmuch as signal processing applications in a single portable device. Since integration through softwareapplications compromises system speed, integration through hardware will be the better compliment. Software Defined Radio (SDR) Technology yields to achieve this small form factor system while keeping power consumption under the limit. SDR enables soft changeable system functionality, such as receiver demodulation technique .In this implementation two type modulation techniques are used, ASK and FSK. The flexibility of changing the receiver functionality in runtime is usually attained by FPGA. However, using a complete FPGA for reconfiguration of a particular functionality is not an efficient method in terms of power consumption and switching time. We proposed a SDR architecture using a recent advancement in FPGAs, called Partial Reconfiguration (PR). PR helps to change certain portion of FPGA, while the restkeeps functioning. It also reduces the total hardware usage and hence the power. The different demodulation technique and other signal processing application from an external memory unit can be loaded into FPGA PR modules while the other parts of FPGA doing a constant data processing.
Challenges in Technology and Reconfiguration of SDR - A Survey
Jeyalakshmi V,Sankaranarayanan K
IETE Technical Review , 2008,
Abstract: "Life goes wireless", a motto for the evolving lifestyle of millions of people has pushed the flowering of several wireless standards spanning short to global coverage. The explosive growth of wireless communication has driven to have a quality radio device at an affordable cost. With the ability to reduce installation costs, add flexibility and easier deployment and maintenance, the attractiveness of wireless technologies needs little reinforcement. Recently this reinforcement turns the researchers to the reconfigurable SDR. In this article, we concentrate on the review of the trends in change and challenging technology in reconfigurable SDR. This is the "any one, anywhere any time", paradigm of intelligent overlay communication establishment that is reconfiguration and re-programmability by software upgrades. The main technical objective of SDR is a versatile reconfiguration platform, which provides interoperability.
Radar Waveform Design for Extended Target Recognition under Detection Constraints
Huadong Meng,Yimin Wei,Xuhua Gong,Yimin Liu,Xiqin Wang
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/289819
Abstract: We address the problem of radar phase-coded waveform design for extended target recognition in the presence of colored Gaussian disturbance. Phase-coded waveforms are selected since they can fully exploit the transmit power with sufficient variability. An important constraint, target detection performance, is considered to meet the practical requirements. The waveform is designed to achieve maximum recognition performance under a control on the achievable signal-to-noise ratio (SNR) of every possible target hypothesis. We formulate the code design in terms of a nonconvex, NP-hard quadratic optimization problem in the cases of both continuous and discrete phases. Techniques based on semidefinite relaxation (SDR) and randomization are proposed to approximate the optimal solutions. Simulation results show that the recognition performance and the detection requirements are well balanced and accurate approximations are achieved.
Waveform Design for Secure SISO Transmissions and Multicasting  [PDF]
Ming Li,Sandipan Kundu,Dimitris A. Pados,Stella N. Batalama
Computer Science , 2013,
Abstract: Wireless physical-layer security is an emerging field of research aiming at preventing eavesdropping in an open wireless medium. In this paper, we propose a novel waveform design approach to minimize the likelihood that a message transmitted between trusted single-antenna nodes is intercepted by an eavesdropper. In particular, with knowledge first of the eavesdropper's channel state information (CSI), we find the optimum waveform and transmit energy that minimize the signal-to-interference-plus-noise ratio (SINR) at the output of the eavesdropper's maximum-SINR linear filter, while at the same time provide the intended receiver with a required pre-specified SINR at the output of its own max-SINR filter. Next, if prior knowledge of the eavesdropper's CSI is unavailable, we design a waveform that maximizes the amount of energy available for generating disturbance to eavesdroppers, termed artificial noise (AN), while the SINR of the intended receiver is maintained at the pre-specified level. The extensions of the secure waveform design problem to multiple intended receivers are also investigated and semidefinite relaxation (SDR) -an approximation technique based on convex optimization- is utilized to solve the arising NP-hard design problems. Extensive simulation studies confirm our analytical performance predictions and illustrate the benefits of the designed waveforms on securing single-input single-output (SISO) transmissions and multicasting.
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