Rudzidatul Akmam Dziyauddin

Flexible online multi-objective optimization framework for ISA100.11a standard in beacon-enabled CSMA/CA mode

Maintaining high quality of service (QoS) for sensor nodes is important in industrial wireless sensor networks (IWSNs). Wide range of factors severely affects QoS; however more research is still needed. In this article, a flexible online multi-objective optimization framework (FOMOF) in carrier sense multiple access with collision avoidance (CSMA/CA) mode is proposed. Nodes are predominantly grouped based on their QoS requirements and then optimized in online mode using a constrained genetic based multi-objective approach. FOMOF to maintain a minimum desired QoS of the pre-determined groups with maximum number of nodes. Furthermore, the packet delivery ratio (PDR) obtained in FOMOF was higher than the one obtained by ISA100.11a standard. Accordingly, the grouping strategy enhanced the number of nodes by 12.5% with End-to-End delay reduction of 16.36% for 27 nodes.

Performance Evaluation of Quality of Service for Joint Packet Dropping and Scheduling

AbstractQuality of Service is particularly necessary to serve delay-sensitive applications in heavy-loaded wireless networks. In this paper we evaluate a strategy of combining packet dropping and scheduling policies at Medium Access Control layer in guaranteeing maximum packet latency for real-time applications. The purpose of this work is to evaluate how significance the mentioned combination schemes can meet the required latency and also the achievable system throughput. For the case study, a real time Polling Service class in the Worldwide Interoperability for Microwave Access System for downlink transmission is assumed. The main analysis is undertaken for User Datagram Protocol (UDP) traffic in stationary and mobile user scenarios under heavy load conditions, and the impact of mixed Transmission Control Protocol and UDP traffic is also investigated. Results show that the introduction of a packet dropping policy ensures that the latency is kept well within the required maximum latency requirement, regardless of the types of scheduler used. However, the packet drop percentage (or packet loss) depends strongly on the types of schedulers. All schedulers show similar goodput performance for low load conditions, and the results can only be distinguished for the cases of heavy load/overloaded conditions.

Performance analysis of Dynamic Burst Mapping in WiMAX system

This paper investigates the effectiveness of dynamic resource allocation scheme in WiMAX (Worldwide Interoperability for Microwave Access) system following to the WiMAX standard. Simulation experiments are performed for the case of MAC PDU (Media Access Control packet data unit) without fragmentation and numerically expanded for the fragmentation case. We used a technique called Dynamic Burst Mapping (DyPBM) to allocate the resources to mobile users, and this is then compared to other non-dynamic resource allocation techniques. Numerical study shows that the dynamic technique (DyPBM) achieves the highest goodput increment of up to 0.7 Mbps when the MAC PDUs are fragmented. Nevertheless, dynamic technique is less effective in the case of without MAC PDU fragmentation since it achieves low channel utilisation over the other non-dynamic techniques. This is because the available slots in some frames are insufficient to support the big PDU sizes as these PDUs (Packet Data Units) are not split into small fragments. This study thus concludes that the dynamic resource allocation is only significant when PDU fragmentation is applied in the WiMAX networks; nevertheless, there is a trade-off in terms of the complexity.

RF Energy Harvesting with Multiple Sources in Wireless Mesh Network

Zarina Mohd Noh*, Abdul Rahman Ramli, Marsyita Hanafi, M Iqbal Saripan, Ridza Azri Ramlee 1,2,3,4 Department of Computer and Communication Systems Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 1,5 Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 75450 Durian Tunggal, Melaka, Malaysia

Crossroads traffic density monitoring and injection mitigation through visual recognition

Monitor and control traffic conditions are important in intelligent transport systems to reduce congestion, especially at intersections. The approach is needed to reduce the negative effects of the congestion at junctions and steps taken to control traffic at the intersection. The project identifies the number of cars through video image detection and thus take into account traffic and road width at each branch junction to resolve congestion by coordinating traffic lights. This project involves with the design, manufacture, and analysis of traffic monitoring system through computer technology and profile intersection. The system notifies the congestion monitored in three stages (empty, medium and many) and the size of the width of the road, road capacity and type of intersection. This study uses Indonesian Highway Capacity Manual (IHCM) with Fuzzy algorithm to detect vehicles using surveillance cameras at four traffic lights junctions. The green light is determined by the density of the vehicle and the type of intersection using adobe flash simulated.

Performance analysis of Radio Environment Map accuracy on resource reuse in multi-channel cellular networks

This paper presents a numerical study to quantify the benefits of using Radio Environment Maps (REM) within resource management techniques. To date, there are no REM studies established to benchmark the impact of REM models and their accuracy for inter-cell interference coordination (ICIC) within multi-channel systems, such as based on OFDMA (Orthogonal Frequency Division Multiple Access). We evaluate REM using a reuse partitioning scheme and it is benchmarked against a system without REM where no-reuse partitioning is employed. Results show that the large interior with REM is able to improve the system efficiency at certain load for low exponents. This study is further extended to the effects of REM information accuracy, such as the predictions of path losses, fading variances as well as the load, on the system performance. It is found that the variation in the load estimation by REM has the greatest effect on the system efficiency, and it is significant for high path loss exponent resulting in significant loss of system efficiency. In contrast, the fading variance accuracy has the least impact on the efficiency performance. This research implies that REM is beneficial in improving the cellular system performance, particularly in intercell-interference coordination.