Informatics Publishing Limited

Rashid A. Saeed ¹, A. F. Ismail ², Mohammad Kamrul Hasan ², Rania Mokhtar ², Sajda K. A. Salih ¹, Wahida Hashim ³

Affiliations
1 Electronics Engineering Department, Sudan University of Science and Technology, SD
2 Electrical and Computer Engineering, International Islamic University Malaysia, MY
3 College of Information Technology, Universiti Tenaga Nasional, MY

Abstract

This paper proposes an algorithm for coexistence in TVWS between IEEE 802.22 and IEEE 802.11af by equal opportunity without increased delay time and decreased throughput, for each of them. Also, an investigation has been conducted for the coexistence problem between the 802.22 and the IEEE 802.11af systems, in the TV White Spaces (TVWS). IEEE 802.22 and IEEE 802.11af are two typical standards envisioned to be widely adopted in the future. However, these two standards are heterogeneous in both power level and PHY/MAC design; as a result coexistence challenge is there. The main focus of this paper is to design a co-channel coexistence scheme for the IEEE 802.22 customer-premises equipment’s (CPEs) as well as the IEEE 802.11af systems. In this paper, the challenges are identified to enable the co-channel coexistence of the IEEE 802.22 and the IEEE 802.11af systems. Afterwards, an algorithm is proposed for coexistence, depending on frame times. The algorithm is applied in two networks in three cases, depending on the amount of transmitting data. The simulation results suggest that the proposed solution has increased the throughput and decreased the waiting time by a noticeable way for IEEE 802.11af.

Keywords

IEEE 802.11af, Interference, TDMA, TVWS, White-Fi

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Rania A. Mokhtar ¹, A. F. Ismail ², Mohammad Kamrul Hasan ², Wahidah Hashim ³, Hajir Abbas ⁴, Rashid A. Saeed ⁴, Shayla Islam ⁵

Affiliations
1 Electronics Engineering Department, Sudan University of Science and Technology, Khartun, SD
2 Electrical and Computer Engineering, International Islamic University Malaysia, Selangor-53100, MY
3 College of Information Technology, Universiti Tenaga Nasional, MY
4 Electronics Engineering Department, Sudan University of Science and Technology, Khartun, SD
5 Department of Electrical and Computer Engineering, Faculty of Engineering, International Islamic University, Jalan Gombak 53100

Abstract

While shifting from one specific single access point to another point, the Mobile IP address permits a single mobile node for keeping an uninterrupted connection with the internet. Nevertheless, when handover occurs, the packets designed for the mobile nodes may have some delay or the risk of getting lost, because of the operations such as Mobile IP handover and link switching delay. This paper presented a novel control function that is called Lightweight Handover Control Function (L-HCF). The purpose of this control function is to improve of the handover performance in the perspective of Mobile IPv6 over wireless networks. The L-HCF functionality allows a router to choose which Access Router(AR)/Access Point (AP)/ address that the mobile node is associated with when movement is needed, by using available IP addresses in its database if the movement operation in side domain or by exchange messages between other routers if the movement alter domain. Thus the Mobile Nodes (MN) can use this address without engaging in the process of Stateless Address Auto-configuration or the procedure of Duplicate Address Detection. The function is implemented analytically then simulated in OPNET. The result shows that, the control function offer minimum latency, less packet loss compared with the standard function of the mobile IPv6.

Keywords

Lightweight Handover Control Function (L-HCF), IP6, IEEE 802.11/Wi-Fi, Handover Latency

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A. H. Yaccop ¹, Y. D. Yao ¹, A. F. Ismail ², K. Badron ², Mohammad Kamrul Hasan ²

Affiliations
1 Department of ECE, Stevens Institute of Technology Hoboken, New Jersey, US
2 Department of ECE, International Islamic University Malaysia, Kuala Lumpur, MY

Abstract

Background/Objectives: Researches disclosed rain attenuation prediction models offered by ITU-R severely underestimate the signal attenuation in tropical region. Improvement can be accomplished by incorporating three in-situ parameters of prediction models. Methods/Statistical Analysis: The locally derived components are rainfall rate, rain height and specific attenuation coefficients. Beacon signal data for MEASAT-I satellite were sampled for one year. Sampling time of 1 minute was chosen for rainfall rate. Both attenuation and rainfall rate were represented in terms of annual cumulative distribution. Rain height data were gathered from related researches and visually compared with radar data of 10 convective and 30 stratiform rain events. Findings: In previous works, these components were treated separately. By combining all three components, rain attenuation prediction model with distinctive accuracy can be acquired compared to the previous results. All previous and current works exhibited significant improvement from the latest ITU-R P.618 revision 12 model. The new result closely fitted in with measured attenuation which was not present in any previous work. This was shown by RMS error of 2.02 dB at availability of 99.9% to 99.999% (0.1% to 0.001% exceedance). Application/ Improvements: Accurate representation of fade margin can be included in link budget analysis by designers for satellite deployment in tropical region.

Keywords

ITU-R, Ku-Band, Rain Attenuation, Satellite, Tropical.

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