Siddarama R. Patil

A survey on spectrum sensing algorithms for cognitive radio

The availability of radio spectrum is limited. The demand for high data transmission requires the increase in the spectrum which over burdens the available frequency spectrum because of licensed spectrum management. But on the other hand the studies indicate that the licensed spectrum is underutilized. Therefore this underutilized spectrum needs to be relocated dynamically so that the spectrum can be used by unlicensed user when it is not used by primary users. This paper provides an overview of spectrum sensing for cognitive radio for opportunistic spectrum access and related research topics The Cognitive Radio (CR) technology requires the detection of primary user signals at the secondary users to dynamically allocate the spectrum hole to the unlicensed user. The important task for cognitive radio is to detect the existence of primary user to reduce interference to the primary user. Therefore spectrum sensing is a most important part of the cognitive radio. A number of promising concepts for spectrum sensing in cognitive radio were briefly presented and discussed in this paper in the area of blind semi-blind and non-blind spectrum techniques.

Stable Backbone Based Multipath Routing Protocol for Mobile Ad-Hoc Networks

Mobile Ad-Hoc Networks (MANETs) consists of wireless mobile nodes communicating without the need of services provided by a centralized administration or established infrastructure. They can be setup anywhere and anytime because they require neither infrastructure nor centralized administration. Because of mobile nodes in MANET, high node mobility causes complexities in route discovery, route stability etc. in which stability is the main reason for data failure. In most of the existing stability based routing protocol link quality and residual energy of each node is estimated during the routing process, result increased delay and overhead. In order to overcome these issues, in this paper, we construct a Stable Backbone Based Multi-Path Routing Protocol for Mobile Ad-Hoc Network (SBMRP). Initially, the nodes with high residual bandwidth, residual power, link quality and low mobility nodes are designated as candidate nodes. Then multiple paths are established between source and destination through these candidate nodes, thus forming a routing backbone. If any candidate node in the path tend to fail due to lack of bandwidth, residual energy or link quality, alternate path through another candidate node is established. By simulation results, we show that proposed technique minimizes the overhead, packet drop, energy and increases the packet delivery rate.

Route stability based on demand multipath routing protocol for Mobile Ad Hoc Networks

A fundamental issue arising in Mobile Ad Hoc NETworks (MANETs) is to select a reliable routing path between nodes to improve routing efficiency by selecting the most stable path so as to reduce the packet drop rate and overhead due to route rediscovery. In this paper, we propose to design a route stability based on demand multipath routing protocol for MANETs named, Stable Backbone based Multipath Routing Protocol (SBMRP) to improve link quality and to select a stable paths between the nodes. Proposed scheme includes selection of candidate nodes and construction of routing backbone to select the stable paths between the source to the destination node. The proposed algorithm has been verified by simulations using Network Simulator 2 (NS-2). The results have been show that the SBMRP outperforms the existing routing protocols by significantly reducing the route discovery and also increases packet delivery ratio and lifetime of nodes by constructing backbone paths between source and destinations.

Signal detection in cognitive radio networks over AWGN, Nakagami-m and Nakagami-q channels

In this paper, we consider the problem of spectrum sensing based on energy detection (ED) method in cognitive radio (CR) over wireless communication channels when users experiences fading and non fading effects. The closed form analytical expressions for the detection probability are derived over non fading Additive White Gaussian Noise (AWGN) channel and Nakagami-m and Nakagami-q fading channels. The detection probability involving Marcum-Q function is replaced by closed form expression. The probability distribution function (PDF) of fading channels is used to obtain the expressions for detection probability. The new derived numerical results are simulated under various parameters. The performance of the derived theoretical expressions closely matches with the simulated results.

Spectrum sensing in cognitive radio networks with known and unknown noise levels

In this study, the authors consider the problem of signal detection in cognitive radio under the cases of known and unknown noise levels. The analysis is focused on maximum eigenvalue-based method which requires the knowledge of noise variance and the ratio of maximum eigenvalue to the trace of covariance matrix. The analytical formulas are derived for threshold calculation and probability of detection for the considered methods. Performance of the considered methods is measured through simulation analysis. The performance comparison between the considered methods and other existing methods is provided. Simulations based on independent and identically distributed signals and wireless microphone signals are presented to verify the various sensing methods.

Performance Evaluation of QoS-Aware Routing Protocols in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) consists of densely populated large number of spatially distributed configurable sensors, to meet the requirements of industrial, military, precision agriculture and health monitoring applications with ease of implementation and maintenance cost. Transmission of data requires both energy and quality of service (QoS) aware routing to ensure efficient use of the sensors and effective access of gathered information. In turn routing technique must provide reliable transmission of data without compromising QoS requirements of applications. We have addressed different routing protocol categories with range of QoS metrics to be achieved, to improve performance of WSNs applications.

Data storage security algorithms for multi cloud environment

Cloud computing technology is considered to be the top most strategic technology in todays world. This is the result made in the advancement in storage technology towards cloud computing. The world of cloud computing has become more and more advanced in the recent years. It has become more and more popular and powerful in gaining everyones attention in the field axdbhof research and business as well. Advanced cryptographic techniques are proposed for performing security much stronger way. Therefore, people from different field especially for business in companies are relying on cloud storage. Auditability is considered as an important factor for securing the cloud environment to overcome the hacking issue. Data auditability has been designed for storing the cloud data. This paper discusses various data security algorithms for public cloud computing area.

Multi-constrained reliable multicast routing protocol for MANETs

Mobile ad hoc network (MANET) is a distributed wireless network with highly dynamic topology. So, the nodes keep moving in and out of the network instantly and a path formed between two distant nodes through several intermediate nodes cannot be maintained for long duration of time. But, the availability of the link between any two nodes can be predicted up to the certain extent based on specific constraints such as the available bandwidth, available power and delay etc. Even then the guaranteed data delivery through the path cannot be made. Therefore, reliable multicast routing in MANET is very challenging problem. This paper proposed a multi-constrained reliable multicast routing protocol (MRMRP) using network coding. This technique initially builds the stable path between the desired distant for data transmission and then uses network coding for recovery of any packet that is lost during data transmission. We demonstrate through simulation results, that the proposed scheme shows its better performance compared to other methods. The simulation results show that the MRMRP increases the packet delivery ratio by reducing the packet drop ratio and control overhead as compared to multicast ad hoc on demand routing protocol (MAODV) and dynamic general coding Scheme (DGC).

Fuzzy logic-based stable multipath routing protocol for mobile ad hoc networks

This paper presents a fuzzy logic stable-backbone-based multipath routing protocol (FLSBMRP) for MANET that provides a high-quality path for communication between nodes. The proposed protocol has two main phases. The first phase is the selection of candidate nodes using a fuzzy logic technique. The second phase is the construction of a routing backbone that establishes multiple paths between nodes through the candidate nodes, thus forming a routing backbone. If any candidate node in the path fails due to a lack of bandwidth, residual energy or link quality, an alternate path through another candidate node is selected for communication before the route breaks, because a candidate node failure may lead to a broken link between the nodes. Simulation results demonstrate that the proposed protocol performs better in terms of the packet delivery ratio, overhead, delay and packet drop ratio than the major existing ad hoc routing protocols.

Sensing Algorithm for Cognitive Radio Networks based on Random Data Matrix

Signal detection is a fundamental problem in Cognitive radio. In this paper a new statistical test is proposed based on random data matrix (RDM) for detecting the signals in noise, as opposed to the eigenvalue based tests. Among the many spectrum sensing methods, the RDM method detects the primary users without any prior information. The performance of the test is compared with energy detection (ED), covariance absolute value (CAV) and eigenvalue based algorithms through simulation analysis. This sensing algorithm can be used for very low SNR signal detection without requiring the knowledge of signal, channel and noise. Simulations are based on wireless microphone and identically and independently distributed (iid) signals.