Author
Ahmad Kamal Hassan
Other affiliations: King Abdulaziz University, Karlstad University
Bio: Ahmad Kamal Hassan is an academic researcher from Ghulam Ishaq Khan Institute of Engineering Sciences and Technology. The author has contributed to research in topics: Beamforming & Multi-user MIMO. The author has an hindex of 6, co-authored 27 publications receiving 144 citations. Previous affiliations of Ahmad Kamal Hassan include King Abdulaziz University & Karlstad University.
Papers
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TL;DR: The paper is a tutorial exposition of modern reliability techniques, which formulate a problem in the Boolean domain, manipulate formulas to achieve disjointness of logically added subexpressions and retain statistical independence of logically multiplied ones, and finally reach a probability-ready expression that is directly transformed back to the probability domain.
33 citations
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TL;DR: The paper treats the problem of survival reliability which is the probability of successful migration of a specific species from a critical habitat patch to destination habitat patches via heterogeneous imperfect corridors and contributes methods for computing a new measure of reliability that arises when paths to destination habitats patches share common corridors.
23 citations
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TL;DR: A spectrum efficient CRN (SE-CRN) is proposed that employs a hybrid underlay-interweave mode of CRNs for secondary users (SUs) under cooperative communication and it is shown through numerical results that SUE can be reasonably enhanced by SE- CRN.
23 citations
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TL;DR: This paper investigates the bottleneck uplink (UL) coverage performance of the MBS edge users in the presence of ICI and DI and uses decoupled association (DeCA) in place of coupled association to further improve UL signal-to-interference ratio.
Abstract: In fifth generation (5G) networks, the densification of small base stations in the coverage region of macro base station (MBS) leads to significant inter-cell interference (ICI). Similarly, drones (a.k.a. unmanned aerial vehicles) have a diverse scope in multifarious 5G assisted applications and, therefore, cause considerable drones interference (DI) as a result of excessive drone usage. This paper investigates the bottleneck uplink (UL) coverage performance of the MBS edge users in the presence of ICI and DI. To mitigate both ICI and DI, we use an efficient resource allocation scheme known as reverse frequency allocation (RFA). Moreover, we use decoupled association (DeCA) in place of coupled association to further improve UL signal-to-interference ratio. The results depict that RFA in conjunction with DeCA overpass all other techniques in terms of improved UL coverage performance because of effective DI and ICI mitigation.
17 citations
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TL;DR: This letter derives a closed-form expression for the outage probability for a general channel model using a recent covariance shaping method and for the conventional Kronecker structured model and presents an outage minimization technique obtained by designing the transmit and receive beamformers.
Abstract: In this letter, we propose techniques for joint transmit and receive beamforming in downlink multi-user MIMO systems under Rayleigh fading channels using knowledge of the second-order statistics. The contribution of our work is twofold. First, we derive a closed-form expression for the outage probability for a general channel model using a recent covariance shaping method and for the conventional Kronecker structured model. Second, we present an outage minimization technique obtained by designing the transmit and receive beamformers. The transmit beamformers maximize the statistics of the signal-to-leakage-plus-noise ratio, while the receive beamformers minimize the cross-covariance of all users. Our techniques are “blind” in the sense that they do not require the transmission of pilot symbols, nor the estimation of the instantaneous state of the channel, making them bandwidth efficient. The derived theoretical results are validated via Monte Carlo simulations and show significant reduction in the outage probability by employing the proposed statistical beamforming techniques.
17 citations
Cited by
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01 Jan 1991TL;DR: It is concluded that properly augmented and power-controlled multiple-cell CDMA (code division multiple access) promises a quantum increase in current cellular capacity.
Abstract: It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >
2,951 citations
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TL;DR: A compact tree shape planar quad element MIMO antenna bearing a wide bandwidth for 5G communication operating in the millimeter-wave spectrum is proposed in this article, where the radiating element of the proposed design contains four different arcs to achieve the wide bandwidth response.
Abstract: A compact tree shape planar quad element Multiple Input Multiple Output (MIMO) antenna bearing a wide bandwidth for 5G communication operating in the millimeter-wave spectrum is proposed The radiating element of the proposed design contains four different arcs to achieve the wide bandwidth response Each radiating element is backed by a 157 mm thicker Rogers-5880 substrate material, having a loss tangent and relative dielectric constant of 00009 and 22, respectively The measured impedance bandwidth of the proposed quad element MIMO antenna system based on 10 dB criterion is from 23 GHz to 40 GHz with a port isolation of greater than 20 dB The measured radiation patterns are presented at 28 GHz, 33 GHz and 38 GHz with a maximum total gain of 1058, 887 and 1145 dB, respectively The high gain of the proposed antenna further helps to overcome the atmospheric attenuations faced by the higher frequencies In addition, the measured total efficiency of the proposed MIMO antenna is observed above 70% for the millimeter wave frequencies Furthermore, the MIMO key performance metrics such as Mean Effective Gain (MEG) and Envelope Correlation Coefficient (ECC) are analyzed and found to conform to the required standard of MEG < 3 dB and ECC < 05 A prototype of the proposed quad element MIMO antenna system is fabricated and measured The experimental results validate the simulation design process conducted with Computer Simulation Technology (CST) software
74 citations
01 Jan 2005
TL;DR: This paper provides a tutorial overview of DSRC applications, assess IEEE 802.11 PHY and MAC layer characteristics, limitations of802.11 in DSRC environments and state ofDSRC, and anticipates that 802.
Abstract: In new intelligent transportation system of North American, the emphasis of the surface transportation infrastructure is based on vehicle-to-vehicle wireless communications,while 75 MHz dedicated short range communications may content to future delivery of rich media via vehicle-to-roadside links. This paper provides a tutorial overview of DSRC applications, assess IEEE 802.11 PHY and MAC layer characteristics, limitations of 802.11 in DSRC environments and state of DSRC. and anticipates that 802.11 specifications will need to be suitably altered to meet requirements for DSRC environments of multihop connectivity, high vehicle mobility and a variety of QOS requirements.
66 citations
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TL;DR: This paper shows that a multiobjective approach does preserve reproductive diversity and makes the case by comparing a pareto multiObjective approach against a single objective approach for solving single objective global optimization problems in the absence of mutation.
Abstract: A number of authors made the claim that a multiobjective approach preserves genetic diversity better than a single objective approach. Sofar, none of these claims presented a thorough analysis to the effect of multiobjective approaches. In this paper, we provide such analysis and show that a multiobjective approach does preserve reproductive diversity. We make our case by comparing a pareto multiobjective approach against a single objective approach for solving single objective global optimization problems in the absence of mutation. We show that the fitness landscape is different in both cases and the multiobjective approach scales faster and produces better solutions than the single objective approach.
63 citations
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TL;DR: An optimizing pattern with “four belts, four zones, one axis, nine corridors, ten clusters and multi-centers” is proposed to provide decision makers with spatial strategies with respect to the conflicts between urban development and ecological protection during rapid urbanization.
Abstract: Urban agglomerations have become a new geographical unit in China, breaking the administrative fortresses between cities, which means that the population and economic activities between cities will become more intensive in the future. Constructing and optimizing the ecological security pattern of urban agglomerations is important for promoting harmonious social-economic development and ecological protection. Using the Harbin-Changchun urban agglomeration as a case study, we have identified ecological sources based on the evaluation of ecosystem functions. Based on the resistance surface modified by nighttime light (NTL) data, the potential ecological corridors were identified using the least-cost path method, and key ecological corridors were extracted using the gravity model. By combining 15 ecological sources, 119 corridors, 3 buffer zones, and 77 ecological nodes, the ecological security pattern (ESP) was constructed. The main land-use types composed of ecological sources and corridors are forest land, cultivated land, grassland, and water areas. Some ecological sources are occupied by construction, while unused land has the potential for ecological development. The ecological corridors in the central region are distributed circularly and extend to southeast side in the form of tree branches with the Songhua River as the central axis. Finally, this study proposes an optimizing pattern with “four belts, four zones, one axis, nine corridors, ten clusters and multi-centers” to provide decision makers with spatial strategies with respect to the conflicts between urban development and ecological protection during rapid urbanization.
57 citations