Chirag Warty

Wireless Power Transfer Using Metamaterial Bonded Microstrip Antenna for Smart Grid WSN

Wireless Power Transfer (WPT) system is a suitable alternative for power transmission where conventional wired power transfer faces geographical challenges. In a long range wireless power transmission system, power is transmitted through microwaves. A highly directive antenna is required for an effective transmission through this system. This paper talk about a circularly polarized microstrip rectangular patch antenna incorporated with a metamaterial slab. Use of microstrip antennas will considerably reduce the size of WPT system in comparison to other microwave antenna. In this paper the modeling and analysis of the wireless power transmission system is done on 2.45 GHz frequency and using GaAs Schottky barrier diode for the rectification of microwave power to DC power at the receiver end. Antenna assigned with metamaterial proposed in paper will enhance the amount of transferred power to wireless sensors network with less radiation loss.

Image compression scheme based on zig-zag 3D-DCT and LDPC coding.

The prime necessity in communication system is utilizing the available bandwidth efficiently. Hence, compression of data to be sent over the link has become inevitable. In this paper, an algorithm for compressing hyperspectral space images based on ZigZag 3D-DCT (Discrete Cosine Transform) technique is proposed. This method converts 2D gray-scale images into a 3 dimensional cube formation of 8*8*8 pixels and is operated with DCT. Thereafter the quantization and zig-zag scanning processes are implemented. After completing the processes, the 1D data vector formed facilitates in achieving better compression using run-length coding. Also, in order to design a complete practical system, a suitable irregular LDPC encoder is implemented in order to mitigate losses present in communication link. The performance of the algorithm is verified by plotting various quality measurement graphs, and determining its dominance over standard JPEG.

De Bruijn sequences as secure spreading codes for wireless communications

In wireless communication systems, physical layer elements are open to possible attacks by eavesdroppers and undesired entities. The basic premise of spread spectrum techniques is to mask user information by spreading the original message over the whole bandwidth. To this aim, pseudorandom codes may be used. However, traditional families of codes are publicly known and no longer trustworthy to provide protection against malicious users. The paper proposes the use of De Bruijn sequences as the next generation set of spreading codes, for their cardinality and correlation properties. Here, different spans of De Bruijn codes are analyzed to examine their performance over spread spectrum channels. It is shown that the codes provide acceptable results with respect to various security tests, like the Golombs postulates, Berlekamps linear complexity, and five basic tests on randomness, recommended by the National Institute of Standards and Technology (NIST).

DS-SS with de Bruijn sequences for secure Inter Satellite Links

Today, both the military and commercial sectors are placing an increased emphasis on global communications. This has prompted the development of several Low Earth Orbit satellite systems that promise a worldwide connectivity and real-time voice, data and video communications. Constellations that avoid repeated uplink and downlink work by exploiting Inter Satellite Links have proved to be very economical in space routing. However, traditionally Inter Satellite Links were considered to be out of reach for any malicious activity and thus little, or no security was employed. This paper proposes a secured Inter Satellite Links based network, built upon the adoption of the Direct Sequence Spread Spectrum technique, with binary de Bruijn sequences used as spreading codes. Selected sequences from the de Bruijn family may be used over directional spot beams. The main intent of the paper is to propose a secure and robust communication link for the next generation of satellite communications, relying on a classical spread spectrum approach employing innovative sequences.

High-speed cluster scanning scheme for three-dimensional constellated image processing

Due to the Human Visual System (HVS) the response to well brightened images is frequency dependent. The Discrete Cosine Transform (DCT) - based compression schemes are capable of separating the perceptually significant information in an image from the information that the eye cannot perceive. Hence in image compression, DCT is most widely used transform. In this paper, an algorithm for compressing images based on Cluster 3D-DCT technique is proposed. This method initially segments the two-dimensional image and then forms the clusters within each segment. These segments are then parallely processed to form a three-dimensional cube of 8*8*8 pixels and is processed with DCT. Thereafter the quantization and zigzag scanning processes are implemented. After completing the processes, the 1D data vector formed facilitates in achieving better compression using run-length coding. The performance of the algorithm is verified by plotting graphs, and determining its dominance over other primitive scanning techniques. The processing time and time required to segment the image along with cluster assignment time is tabulated. The cluster scanning which is a parallel progression proves to be faster compared to Spiral, ZigZag and Interleaving scanning schemes.

De Bruijn sequences for secure scrambling at Long Term Evolution - Advanced physical layer

The intent of the paper is to propose a new set of scrambling codes to spread information in a manner that provides superior physical layer security. In wireless communication systems, physical layer elements are vulnerable to possible security-related attacks by undesired entities. Basic premise of a reliable communication infrastructure is to mitigate risks related to violations of the user information integrity, authenticity, and to provide efficient control and management information flow. The 3GPP Long Term Evolution - Advanced achieves this goal by using robust scrambling technique for control channel information, by means of binary Gold sequences used as scrambling codes. Gold sequences provide good correlation-related properties, however they have been known for a long time, thus they are weak in security-related features, starting from their very limited cardinality. This paper suggests the use of De Bruijn sequences as the next generation set of scrambling codes, for their huge cardinality and satisfactory correlation-related properties. Different spans of De Bruijn codes are analyzed to examine their performance, with a specific emphasis on sequences of length 32, that are comparable to the Gold codes currently suggested by the standard. De Bruijn sequences are seen to provide much more favorable results, even with respect to security-related tests.

Adaptive physical layer security using code bank of sequences for CDMA

Wireless security is an important concern in todays technological world. Wireless devices are used to access data and private applications. From broadband to Wi-Fi, 3G to LTE Advanced, WiMAX to satellite communication every network demands on-the-air security from attacks. Tapping or Jamming attacks leak the secret data, while Service Disruption Attacks affecting QoS (Quality of Service) are relatively easy to perform. In CDMA, the channel and antenna dependent attacks are quite critical to avoid because of its wide bandwidth usage. The critical exchange of time and frequency parameters makes the physical layer elements vulnerable to security related attacks. In order to enable data security and secrecy, there is need of signal protection at the physical layer of CDMA system. Gold codes, M-sequences, OVSF and De-Bruijn sequences were used individually in wireless systems for scrambling purposes in previous proposals. These codes have their own advantages and disadvantages, when channel bandwidth and noise conditions change. This paper proposes a system which would select scrambling codes from a bank of all these mentioned codes depending upon the Signal to Noise Ratio (SNR) or Channel State Information (CSI). This code bank technique is shown as a highly practical solution in selection of proper code for mitigation of attacks and hence, to provide security at the physical layer of CDMA.

De Bruijn sequences for DS/CDMA transmission: Efficient generation, statistical analysis and performance evaluation

Nowadays, Direct Sequence Code Division Multiple Access (DS/CDMA) still represents the core technology for the physical layer of several commercially-remunerative applications and standards, ranging from cellular networking, radiolocalization, satellite communications, automotive radar, etc. A very critical issue of Spread Spectrum and CDMA is still represented by the necessity of keeping the probability of intercept as lowest as possible, therefore, a secure information hiding must be guaranteed at the physical layer. The use of De Bruijn binary sequences may represent a valuable solution to the aforesaid issue. De Bruijn sequences are nonlinear shift register sequences, whose sets are characterized by a cardinality much larger than the sequence length. This paper aims at considering some significant aspects about the usage of De Bruijn sequences in DS/CDMA, not yet addressed by prior works: the performance of De Bruijn sequences in asynchronous DS/CDMA transmission is assessed by means of explicit computations of multi-user interference statistics (variance and kurtosis), and closed form Bit-Error-Probability (BEP) analytic expressions. Numerical results on the obtained BEP after Reed-Solomon coding evidence that, when randomly selected, De Bruijn sequences perform very close to Gold sequences having the same length. The performance provided by De Bruijn sequences get remarkably better than the Gold ones when a proper selection procedure, aimed at minimizing the pairwise aperiodic cross-correlation, is adopted. The selection procedure and the corresponding results are discussed in details within the paper.

Transmission of big data over MANETs

Big data recently has gained tremendous importance in the way information is being disseminated. Transaction based data, unstructured data streaming to and fro from social media, increasing amounts of sensor and machine-to-machine data and many such examples rely on big data in conjunction with cloud computing. It is desirable to create wireless networks on-the-fly as per the demand or a given situation. In such a scenario reliable transmission of big data over mobile Ad-Hoc networks plays a key role. Limitations like low bandwidth, congestion and loss of packets pose a challenge for such systems. Hence an effective routing mechanism plays an important role. The proposed protocol is Multi-path QoS Routing (MPQR) protocol. Existing protocols try to establish a single path for communication. The proposed paper focuses on distributing tickets in the network. Also it can be divided into sub-tickets to get an optimum multi-path. The principal advantage is its high performance in the case of bandwidth limited environments when compared to existing protocols.

Secured scrambling codes for vehicular control and navigation

The intent of the paper is to propose a new set of scrambling codes at the physical layer in a manner that provides much higher security and reliability. In Vehicular Communication system at the physical layer the neighboring node search procedure consist of series of synchronization stages by which the client determines time and frequency parameter necessary to demodulate the downlink and to transmit uplink signals with correct timing. This critical exchange makes the physical layer elements vulnerable to possible security related attacks by undesired entities. At present the popular standards use binary Gold as scrambling sequences for the control channel. Gold codes are known to provide good correlational properties but lack severely in other areas like cardinality. This paper suggests the use of De Bruijn sequences as next generation set of scrambling codes especially for their huge cardinality and correlation related properties. Performance of binary modified De Bruijn codes is analyzed with a specifies emphasis on length 31 so as to compare it with the Gold codes of length 31 currently suggested by the standard. De Bruijn sequences are seen to provide much more favorable results as compared to Gold codes.