Hafizal Mohamad

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Providing end-to-end communication in heterogeneous Internet working environments is a challenge. Handover delay is one of the problematic issues that users are face in the heterogynous networks. However, in the case of both WiMAX and WiFi technologies located at the same base station (BS); the vertical handover (VHO) delay will be less compared with two(More)
—Wireless mesh network has been considered as a viable solution to offer broadband connectivity to rural community due to its ability to provide extended coverage and scalable deployment. However, there are still impediments that need to be addressed in terms of throughput degradation, latency and interference due to multi hop transmission and potential(More)
Over recent years, enormous amounts of research in wireless sensor networks (WSNs) have been conducted, due to its multifarious applications such as in environmental monitoring, object tracking, disaster management, manufacturing, monitoring and control. In some of WSN applications dependent the energy-efficient and link reliability are demanded. Hence,(More)
Cognitive radio (CR) has been proposed to enable unlicensed users (or secondary users, SUs) to exploit the underutilized licensed channels (or white spaces) owned by the licensed users (or primary users, PUs). This article presents a simple and pragmatic reinforcement learning (RL)-based routing scheme called Cognitive Radio Q-routing (CRQ-routing).(More)
It is well-known that clustering partitions network into logical groups of nodes in order to achieve energy efficiency and to enhance dynamic channel access in cognitive radio through cooperative sensing. While the topic of energy efficiency has been well investigated in conventional wireless sensor networks, the latter has not been extensively explored. In(More)
Cognitive radio (CR) with dynamic spectrum allocation (DSA) allows new or secondary devices to opportunistically access a portion of spectrum, which belongs to primary (licensed) users (PU). This allows the secondary users (SU) to transmit data services when the PUs are not using the spectrum. However, problem arises when SU experiences interrupted services(More)
IEEE 802.16j Multihop Relay (MR) is an optional deployment introduced to enhance the coverage and performance of WiMAX network without the need for deploying costly Base Stations (BSs). Multihop Relay network comprises of Multihop Relay BS (MRBS) and Relay Stations (RSs). This paper proposes mesh topology for IEEE 802.16j using adaptive RS group scheduling.(More)