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Lukman Audah

Universiti Tun Hussein Onn Malaysia, Johor, Malaysia

Author-ID : 2372394

Computer Science & IT Electrical & Electronics Engineering

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Adaptive Antenna Selection and Power Allocation in Downlink Massive MIMO Systems Adeeb Salh; Lukman Audah; Nor Shahida M Shah; Shipun A Hamzah
International Journal of Electrical and Computer Engineering (IJECE) Vol 7, No 6: December 2017
Publisher : Institute of Advanced Engineering and Science

Massive multi-input, multi-output (MIMO) systems are an exciting area of study and an important technique for fifth-generation (5G) wireless networks that support high data rate traffic. An increased number of antenna arrays at the base station (BS) consumes more power due to a higher number of radio frequency (RF) chains, which cannot be neglected and becomes a technical challenge. In this paper, we investigated how to obtain the maximal data rate by deriving the optimal number of RF chains from a large number of available antenna arrays at the BS when there is equal power allocation among users. Meanwhile, to mitigate inter-user-interference and to compute transmit power allocation, we used the precoding scheme zero forcing beamforming (ZFBF). The achievable data rate is increased because the algorithm of ZFBF enables the choosing of the maximum power in relation to the optimal antenna selection. We conclude that the transmit power allocation allows the use of less number of RF chains which provides the maximum achievable data rate depending on the optimal RF chain at the BS.

QoS based Admission Control using Multipath Scheduler for IP over Satellite Networks Lukman Audah; Zhili Sun; Haitham Cruickshank
International Journal of Electrical and Computer Engineering (IJECE) Vol 7, No 6: December 2017
Publisher : Institute of Advanced Engineering and Science

This paper presents a novel scheduling algorithm to support quality of service (QoS) for multiservice applications over integrated satellite and terrestrial networks using admission control system with multipath selection capabilities. The algorithm exploits the multipath routing paradigm over LEO and GEO satellites constellation in order to achieve optimum end-to-end QoS of the client-server Internet architecture for HTTP web service, file transfer, video streaming and VoIP applications. The proposed multipath scheduler over the satellite networks advocates load balancing technique based on optimum time-bandwidth in order to accommodate the burst of application traffics. The method tries to balance the bandwidth load and queue length on each link over satellite in order to fulfil the optimum QoS level for each traffic type. Each connection of a traffic type will be routed over a link with the least bandwidth load and queue length at current time in order to avoid congestion state. The multipath routing scheduling decision is based on per connection granularity so that packet reordering at the receiver side could be avoided. The performance evaluation of IP over satellites has been carried out using multiple connections, different file sizes and bit-error-rate (BER) variations to measure the packet delay, loss ratio and throughput.

Inverted Diamond-shaped Notched Substrate and Patch for High-frequency Interference on Ultra-wideband Antenna Raed Abdulkareem Abdulhasan; Khairun Nidzam Ramli; Rozlan Alias; Lukman Audah; Abdul Rashid Omar Mumin
International Journal of Electrical and Computer Engineering (IJECE) Vol 7, No 6: December 2017
Publisher : Institute of Advanced Engineering and Science

Notches loaded on a patch antenna can affect significantly on ‎the antenna impedance matching. Therefore, notching technique is an efficient way to reduce ‎the electromagnetic interference with unwanted bands. In this paper, a ‎novel inverted diamond‏-‏shaped closed-end slot on a substrate and ‎vertex-fed printed hexagonal patch ultra‏-‏wideband antenna is proposed for high-frequency band rejection. This antenna is fed using ‎coplanar waveguide, and it is optimised by veering several patch ‎parameters which further improved the inter bandwidth at both the ‎lower and upper bands. However, the centre-notched band is shifted ‎from 6 GHz to 7.5 GHz by cutting the inverted diamond shape in a ‎special process. The developed ultra-wideband antenna is verified by ‎comparing the simulation results with the measurement results. The ‎measured results with a fractional bandwidth of 133% have a good ‎agreement with the simulation results 146%. Moreover, the measured radiation showed omnidirectional patterns‎.

Maximizing Energy Efficiency for Consumption Circuit Power in Downlink Massive MIMO Wireless Networks Adeeb Salh; Lukman Audah; Nor Shahida M. Shah; Shipun A. Hamzah
International Journal of Electrical and Computer Engineering (IJECE) Vol 7, No 6: December 2017
Publisher : Institute of Advanced Engineering and Science

Massive multi-input–multi-output (MIMO) systems are crucial to maximizing energy efficiency (EE) and battery-saving technology. Achieving EE without sacrificing the quality of service (QoS) is increasingly important for mobile devices. We first derive the data rate through zero forcing (ZF) and three linear precodings: maximum ratio transmission (MRT), zero forcing (ZF), and minimum mean square error (MMSE). Performance EE can be achieved when all available antennas are used and when taking account of the consumption circuit power ignored because of high transmit power. The aim of this work is to demonstrate how to obtain maximum EE while minimizing power consumed, which achieves a high data rate by deriving the optimal number of antennas in the downlink massive MIMO system. This system includes not only the transmitted power but also the fundamental operation circuit power at the transmitter signal. Maximized EE depends on the optimal number of antennas and determines the number of active users that should be scheduled in each cell. We conclude that the linear precoding technique MMSE achieves the maximum EE more than ZF and MRTbecause the MMSE is able to make the massive MIMO system less sensitive to SNR at an increased number of antennas.

Co-Authors Abdul Rashid Omar Mumin Adeeb Salh Haitham Cruickshank Khairun Nidzam Ramli Nor Shahida M Shah Nor Shahida M. Shah Raed Abdulkareem Abdulhasan Rozlan Alias Shipun A Hamzah Shipun A. Hamzah Zhili Sun

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