Norazizah Mohd Aripin

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— Limited available spectrum and the inefficiency in the spectrum usage necessitate the use of Cognitive Radio (CR) approach to exploit the existing wireless spectrum opportunistically. To achieve the goal of CR, it is a fundamental requirement that the cognitive user (CU) performs spectrum sensing to detect the presence of the primary user (PU) signal(More)
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We propose an MAC centric cross-layer approach to address the problem of multimedia transmission over cognitive Ultra Wideband (C-UWB) networks. Several fundamental design issues, which are related to application(More)
Enabling video transmission to be maintained at an acceptable level under unreliable and time-varying wireless channels in a non-trivial challenge. The main challenge in enabling video transmission over UWB WPAN lies on how to meet the QoS requirements (ie: delay, jitter, PSNR) under time-varying spectral resources, video frame dependencies, limited power(More)
— Ultra-wideband (UWB) and cognitive radio (CR) are two exciting technologies that offer new approaches to exploit the existing wireless spectrum opportunistically to overcome the limited available spectrum and the inefficiency in the spectrum usage. In Cognitive Ultra Wideband (C-UWB) system which utilizes low power transmission, the key challenge in(More)
Cognitive radio is a promising solution in improving spectrum utilization efficiency by allowing unlicensed users to access idle licensed spectrum opportunistically. Cognitive Radio Cognitive Network (CRCN) supports multi-interface multi-channel functions in Network Simulator 2 (NS-2). However, CRCN only supports cognitive functions to two MAC protocols(More)
Asynchronous iterative water filling (AIWF), which is based on Shannon Theory, distributes resources fairly among users. Unlike Game Theory that requires users to exchange packets, AIWF does not require users to exchange packets for achieving Nash equilibrium. Conventionally, AIWF computes optimal transmit power for multiple users in Gaussian Wireless(More)
The demand of quality of service (QoS) for multimedia transmission over wireless network raises huge challenges such as time-varying channel conditions, limited resources, tight delay constraints, high bandwidth demand and complex protocol design. Layered design is proven to perform well in wired networks. However, doing so is not suitable in wireless(More)
Cross layer design is considered as an attractive strategy to enable multimedia transmission over cognitive ultra wide band (C-UWB) system experiencing time-varying channel conditions and traffic characteristics. The close dependency among various parameters across protocol stacks need to be addressed to determine the optimum cross layer approach. Hence,(More)
Over the past few decades, unprecedented growth in wireless communications, networking and video-coding technologies have stimulate numerous applications such as video on demand and interactive video telephony. Ultrawideband technology (UWB) which offers high data rate with low transmit power, becomes a very promising wireless platform for video(More)
The Cognitive Radio (CR) enables spectrum aware communication protocols to sense the spectral environment and use this information to opportunistically provide wireless links that meet the user communications requirements optimally. CR techniques can be applied to Multi-band OFDM based UWB systems in order to continuously detect the presence of primary(More)
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