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Your search keyword '"Imran, Muhammad Ali"' showing total 14 results
Start Over Author "Imran, Muhammad Ali" Journal ieee transactions on communications
14 results on '"Imran, Muhammad Ali"'

1. On the Design of Broadbeam of Reconfigurable Intelligent Surface

Author

Lin, Xinyi, Zhang, Lei, Tukmanov, Anvar, Liu, Yihong, Abbasi, Qammer H., and Imran, Muhammad Ali

Abstract

Reconfigurable intelligent surface (RIS) has been identified as a promising disruptive innovation to realize a faster, safer and more efficient communication system. In this paper, we study the broad beamwidth design of RIS. A problem is formulated to achieve broadbeam with maximum and equal power gain within a pre-defined angular region given constraints of the unit modulus weights of RIS. Since the formulated problem is non-convex, where the optimal solution cannot be analytically obtained, we propose the difference-of-convex-based semi-definite programming (DC-SDP) algorithm. In addition, as important guidance of signal coverage for arbitrary angular regions, we mathematically derive the relationship between the angular range of the spatial sector and the maximum average received power. The upper bounds of the average received power with different RIS configurations are also obtained, where uniform rectangular array (URA) and uniform linear array (ULA) are considered. Simulation results demonstrate the effectiveness of our derivations and verify that our proposed DC-SDP algorithm is applicable in practical applications and outperforms other baseline methods. Overall, this work can be viewed as a foundation for the practical implementation of RIS on coverage enhancement and can also be seen as an initial step towards achieving channel estimation.

Published
2024
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14. Low-Complexity Energy-Efficient Resource Allocation for the Downlink of Cellular Systems.

Author

Heliot, Fabien, Imran, Muhammad Ali, and Tafazolli, Rahim

Subjects
*ENERGY consumption, *COMPUTER networks, *ALGORITHMS, *CELL phone systems, *MOBILE communication systems
Abstract

Energy efficiency (EE) is undoubtedly an important criterion for designing power-limited systems, and yet in a context of global energy saving, its relevance for power-unlimited systems is steadily growing. Equally, resource allocation is a well-known method for improving the performance of cellular systems. In this paper, we propose an EE optimization framework for the downlink of planar cellular systems over frequency-selective channels. Relying on this framework, we design two novel low-complexity resource allocation algorithms for the single-cell and coordinated multi-cell scenarios, which are EE-optimal and EE-suboptimal, respectively. We then utilize our algorithms for comparing the EE performance of the classic non-coordinated, orthogonal and coordinated multi-cell approaches in realistic power and system settings. Our results show that coordination can be a simple and effective method for improving the EE of cellular systems, especially for medium to large cell sizes. Indeed, by using a coordinated rather than a non-coordinated resource allocation approach, the per-sector energy consumption and transmit power can be reduced by up to 15% and more than 90%, respectively. [ABSTRACT FROM PUBLISHER]

Published
2013
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