Institute of Signals

Islamabad, Pakistan

Institute of Signals

Islamabad, Pakistan

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Sultan K.,KING.INFO | Zafar B.A.,KING.INFO | Zubair M.,Institute of Signals | Khan Z.S.,Institute of Signals
Proceedings - 2016 3rd International Conference on Mathematics and Computers in Sciences and in Industry, MCSI 2016 | Year: 2016

In an underlay spectrum sharing environment, relay selection stands as one of the fascinating techniques to address the challenge of performance enhancement of secondary communication via cognitive relays. In this paper, a similar constrained optimization problem is discussed in which a secondary source-destination pair is assisted by a potential Relay assisted Cognitive Radio (RCRN) in the worst-case scenario when line-of-sight (LOS) path is not available to enable the communication. In order to solve this sophisticated problem, we perform multiple relay selection under the assumption of availability of perfect channel state information (CSI) and propose two novel techniques; one based on Artificial Bee Colony (ABC) evolutionary computing and the second based on Fuzzy Rule Based System (FRBS). Both proposed techniques aim to maximize the signal-To-noise ratio (SNR) at the destination keeping in view the transmit power and interference constraints. The effectiveness of the schemes is highlighted through simulation results, along with their comparison. ©2016 IEEE.


Ghauri S.A.,Isra University of Pakistan | Ghauri S.A.,International Islamic University, Islamabad | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | And 4 more authors.
Scientific World Journal | Year: 2014

A Gabor filter network based approach is used for feature extraction and classification of digital modulated signals by adaptively tuning the parameters of Gabor filter network. Modulation classification of digitally modulated signals is done under the influence of additive white Gaussian noise (AWGN). The modulations considered for the classification purpose are PSK 2 to 64, FSK 2 to 64, and QAM 4 to 64. The Gabor filter network uses the network structure of two layers; the first layer which is input layer constitutes the adaptive feature extraction part and the second layer constitutes the signal classification part. The Gabor atom parameters are tuned using Delta rule and updating of weights of Gabor filter using least mean square (LMS) algorithm. The simulation results show that proposed novel modulation classification algorithm has high classification accuracy at low signal to noise ratio (SNR) on AWGN channel. © 2014 Sajjad Ahmed Ghauri et al.


Khan S.U.,Isra University of Pakistan | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Zaman F.,IIU | And 3 more authors.
The Scientific World Journal | Year: 2014

Three issues regarding sensor failure at any position in the antenna array are discussed. We assume that sensor position is known. The issues include raise in sidelobe levels, displacement of nulls from their original positions, and diminishing of null depth. The required null depth is achieved by making the weight of symmetrical complement sensor passive. A hybrid method based on memetic computing algorithm is proposed. The hybrid method combines the cultural algorithm with differential evolution (CADE) which is used for the reduction of sidelobe levels and placement of nulls at their original positions. Fitness function is used to minimize the error between the desired and estimated beam patterns along with null constraints. Simulation results for various scenarios have been given to exhibit the validity and performance of the proposed algorithm. © 2014 S. U. Khan et al.


Atta-Ur-Rahman,Barani Institute of Information Technology | Atta-Ur-Rahman,Institute of Signals
2013 World Congress on Nature and Biologically Inspired Computing, NaBIC 2013 | Year: 2013

Optimum allocation of resources is demand of every modern communication system. In this way the transmission parameters like code rate, modulation size and power are optimally chosen to enhance the overall system throughput while satisfying certain constraints at the same time. A similar constrained optimization problem is focused for OFDM environment and solved by proposed Fuzzy Rule Based System (FRBS) and Particle Swarm Optimization (PSO). In this proposal FRBS is used for adapting code rate and modulation size while PSO is used for adaptive power. Significance of the proposed scheme is shown through the simulations. © 2013 IEEE.


Khan S.U.,Isra University of Pakistan | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Zaman F.,IIU | Naveed A.,IIU
Progress In Electromagnetics Research B | Year: 2013

In this paper, we have addressed three major problems of uniform linear array in case of a sensor failure at any position. We assume that sensor position is known. The problems include increase in sidelobe levels, displacement of nulls and diminishing of null depth. The desired null depth is achieved by making the weight of symmetrical counterpart element passive. Genetic algorithm (GA) along with pattern search (PS) is used for reduction of sidelobe levels, and adjustment of nulls. Fitness function minimizing the error between the desired and estimated beam pattern along with null constraints is used. Simulation results for diversified scenarios have been given to demonstrate the validity and performance of the proposed algorithm.


Basit A.,International Islamic University, Islamabad | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Khan W.,International Islamic University, Islamabad | And 2 more authors.
International Journal of Antennas and Propagation | Year: 2014

A novel design of a cognitive radar (CR) hybridized with a phased array radar (PAR) having a low probability of intercept (LPI) transmit beam forming is proposed. PAR directed high gain property reveals its position to interceptors. Hence, the PAR high gain scanned beam patterns, over the entire surveillance region, are spoiled to get the series of low gain basis patterns. For unaffected array detection performance, these basis patterns are linearly combined to synthesize the high gain beam pattern in the desired direction using the set of weight. Genetic algorithm (GA) based evolutionary computing technique finds these weights offline and stores to memory. The emerging CR technology, having distinct properties (i.e., information feedback, memory, and processing at receiver and transmitter), is hybridized with PAR having LPI property. The proposed radar receiver estimates the interceptor range and the direction of arrival (DOA), using the extended Kalman filter (EKF) and the GA, respectively, and sends as feedback to transmitter. Selector block in transmitter gets appropriate weights from memory to synthesize the high gain beam pattern in accordance with the interceptor range and the direction. Simulations and the results validate the ability of the proposed radar. © 2014 Abdul Basit et al.


Khan W.,International Islamic University, Islamabad | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Basit A.,International Islamic University, Islamabad | Zubair M.,International Islamic University, Islamabad
Wireless Personal Communications | Year: 2015

In this paper, we have proposed a double pulse multiple input multiple output–frequency diverse array (MIMO–FDA) radar to improve the range-angle localization of the target. Although frequency diverse array (FDA) radar has been widely used to generate both range and angle dependent beamforming, however, it is difficult for FDA to localize the target in both dimensions due to strong coupling of range and angle dimension. To overcome this inability of FDA radar, a double pulse based MIMO–FDA has been presented here. MIMO–FDA can be obtained by partitioning of FDA transmit array into subarrays and then transmit a unique waveform from each subarray. The resultant MIMO–FDA radar will send a pulse with zero frequency increment to locate the target in angle dimension, which is followed by a pulse with suitable frequency increment to locate the target in range dimension. Using the MIMO–FDA radar with double pulse method has improved the range-angle localization of the target. Simulations and results have verified the effectiveness of the proposed radar. The Cramer Rao lower bound for the proposed radar has also been derived and compared with the double pulse FDA radar. © 2015, Springer Science+Business Media New York.


Zaman F.,IIU H | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Naveed A.,Isra University of Pakistan | Khan Z.U.,IIU H
Research Journal of Applied Sciences, Engineering and Technology | Year: 2012

In this study, we propose a method based on Particle Swarm Optimization for estimating Direction of Arrival of sources impinging on uniform linear array in the presence of noise. Mean Square Error is used as a fitness function which is optimum in nature and avoids any ambiguity among the angles that are supplement to each others. Multiple sources have been taken in the far field of the sensors array. In Case-I the sources are assumed to be far away from each other whereas, in case-II they are assumed to be close enough to each other. The reliability and effectiveness of this proposed algorithm is tested on the bases of comprehensive statistical analysis. The proposed algorithm require single snapshot and can be applied in real time situation. © Maxwell Scientific Organization, 2012.


Atta-Ur-Rahman,Pmas Arid Agriculture University | Atta-Ur-Rahman,Institute of signals | Zaidi D.-E.-N.,Pmas Arid Agriculture University | Salam M.H.,The University of Lahore | Jamil S.,Pmas Arid Agriculture University
13th International Conference on Hybrid Intelligent Systems, HIS 2013 | Year: 2014

In this paper a novel technique for user behavior classification is proposed using Fuzzy Rule Based System (FRBS). Using this technique a network user can be monitored and his/her behavior can be classified depending on his/her activities like unauthorized websites usage, attempting to breach in network security, firewalls, unauthorized services access and frequency of attempts etc. The information about a user is obtained by his/her web, database, hardware and other applications logs. FRBS classifies a user to one of the predefined categories based on the information extracted from user logs. This would great help in network security and privacy as well as users may be guided for sincere mistakes and other measures may be taken by the organization. Significance of the proposed scheme is shown by examples and results. © 2013 IEEE.


Ghauri S.A.,NUML | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Malik A.N.,NUML | And 3 more authors.
Research Journal of Applied Sciences, Engineering and Technology | Year: 2013

In this study, we have presented that Higher Order Cummulants (HOC) based modulation recognition scheme for Pulse Amplitude Modulation (PAM), Quadrature Amplitude Modulation (QAM) and Phase Shift Keying (PSK) modulated signals having orders of 2 to 64. Modulation recognition is a process to recognize the signal modulation type which is received by the receiver in the presence of channel noise. The HOC based MR is accomplished in two modules. First is feature extraction using higher order cummulants. These features are distinct for different modulated signals. Second is recognition process which gives decision based upon the features extracted from higher order cummulants. The Probability of Correctness (POC) curves shows the recognition accuracy for sample size and number of iterations. The Additive White Gaussian Noise (AWGN) is considered throughout the simulations. © Maxwell Scientific Organization, 2013.

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