Shikha Nema

Resource Optimization Using Software Defined Networking for Smart Grid Wireless Sensor Network

There has been a decade of extensive research on application specific wireless sensor networks (WSNs). The recent development in communication network technologies makes it practical to realize a new WSN paradigm or controlling the control plane with the new group of by software defined networking (SDN) based on Open Flow. The Open Flow technology which is known for standardization and compatibility network Virtualization has brought a lot of innovative solutions in the field of research. In WSNs, sensor node are complex, highly dense and hence difficult to move. Network topology fast changes with time by using routing protocol, network topology, load balancing, power optimization, security and other factors. In this paper, the concept of SDN in WNS is introduced where Open Flow is the controller part of network.

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.

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.

Spanner Shape Monopole MIMO Antenna with High Gain for UWB Applications

A compact planar two-element spanner shape ultra-wideband multiple input multiple output antenna for UWB applications is proposed. The investigated MIMO antenna comprises two spanner shape radiators separated by distance of 0.25λ with microstrip line feed. The monopole configuration is used to achieve UWB requirement. The antenna prototype is fabricated using FR4 substrate. The antenna is electrically small in size (59.5 mm × 52 mm). The final design of monopole MIMO antenna has return loss less than −10 dB and isolation below −15 dB over the range of 2–12 GHz covering ultra-wideband frequency range. The correlation coefficient between two antenna elements is less than 0.02. The peak gain of antenna is 6.79 dBi for wireless application with efficiency around 90%. The significant improvement in bandwidth, return loss, VSWR, gain, efficiency and envelope correlation coefficient is observed in investigated antenna in comparision with single-element spanner shape antenna. Simulated results are in accordance with measured one.

Radio frequency identification system for asset tracking and inventory management in hospitals

Asset tracking and maintaining records of consumables in hospital industry has been monotonous labor work for decades. Technological evolution has alleviated manual work which further restrained erratum approach in data management. The high-value assets in hospitals are misplaced, lost, or purloined which affects hospital revenue and patients security. The Radio Frequency Identification system based on wireless communication yields a solution to inappropriate data management. The system is comprised of software integrated with hardware for management and tracking of assets by addressing the solution to the internal pilfering of assets and problems encountered during the tedious vendor invoice payment process. This system consists of Radio Frequency Identification reader interfaced with Microsoft Visual Studio 2012 connected to the back-end Microsoft SQL (Structured Query Language) server database. The reader is placed at the checkpoints and in the drug store in the hospital environment. The Radio Frequency Identification tags attached to the assets are identified by the reader and database is updated with information stored in tags. The arrival and outgoing timing of assets are recorded for security purpose. In the case that if any assets get misplaced or purloined the timing and location of the asset will be traced. Furthermore, a brief elucidation of the system is being provided along with benefits of prolonged usage in the health care industry.

Design of multi-band planar diversity antenna for bandwidth and gain enhancement

Three element multi-band planar diversity antenna with large bandwidth have been proposed and presented in this letter. The objective is to design multiband, high gain diversity antenna with reduced mutual coupling appropriate for many wireless applications such as WLAN, LTE, WiMax, Short range RADAR, satellite applications etc. Diversity antenna module is composed of three elements placed parallel to each other with spacing λ/8. Each element is modified with inset slit on upper side of radiator. This antenna has compact size of 76.76 mm × 22.74 mm. The proposed antenna has been simulated and investigated using mentor graphics IE3D software. Fabrication of antenna is done by using FR4 substrate and scattering (S) parameters have been measured using vector network analyzer. Antenna shows minimum mutual coupling below −20 dB, four resonating frequencies with highest bandwidth of 800 MHz and maximum gain of 7.3 dBi. The measured results of S-parameters validate the simulated results.

Distributed Space Frequency Coded Cooperative Network with Asymmetric Fading Channels

The wireless communication system frequency diversity can be exploited with the help of Space frequency coding. In order to gain maximum frequency diversity various environment criteria needs to be considered. This paper proposes a practical approach of Distributed Space Frequency Coding [DSFC] for non-identically distributed [i.n.d] fading environment. As the geographical location of nodes is different, accordingly the signal over the link will also experience different fading. One link may experience Rayleigh fading and other link may experience rician fading. When all the nodes are in shadow region, then it obviously shows poor performance as there is no direct line of sight [NLOS]. On other hand, when all link experiences rician fading, then it shows better performance as there is direct line of sight [LOS]. In asymmetric fading, each link experiences different type of fading depending on the location of the receiving node. Two types of Asymmetric Fading scenarios are designed for DSFC with direct link and without direct link. Asymmetric type I is designed for relay nodes that are located in better area compared to destination node. Asymmetric type II is designed for destination node which is located in better area compared to relay nodes. All these symmetrical and Asymmetrical fading scenarios are performed for both Amplify and Forward [AAF] and Decode and Forward [DAF] relaying protocol. Different modulation effect on proposed DSFC is compared for both relaying protocol. For both relaying protocol, it is observed that Asymmetric Type I shows better performance than Asymmetric Type II and Rayleigh fading.

Three dimensional diversity for closed proximity MIMO systems

The problem that needs to be consider in a multi user distributive and decentralized network is the interception of transmitted signals by an undesirable node. A decentralized system is nothing but a data processing system in which all information is processed locally without the need for a Central Processing Facility where various effects like multipath and scattering causes non- orthogonality of the symbols. To overcome these problems spatial, time and frequency diversity can be used. This paper proposes a three dimensional (Space, Time and Frequency) diversity involving frequency hopping and space time coding technique. A three dimensional system is demonstrated to support heterogeneous networks in LTE advanced standards. Because of limited spectrum and absence of a protected physical boundary, wireless systems face much more serious challenges in capacity and security than wired networks. When transmitted through the air link, wireless signals are more prone to jamming and interception. The main purpose of Frequency hopping (FH) technique is to avoid the interference which is likely to happen in wireless systems. To improve system performance against malicious nodes a space-time coded frequency hopping (STC-FH) based on the orthogonal frequency division multiple access (OFDMA) is proposed. The system considers Almouti block codes and Trellis codes to achieve diversity. The results considers orthogonal frequency division multiplexing which uses cyclic prefix in a space time block coding (STBC) transmission scheme.