Zhan Wei Siew

Energy efficient clustering algorithm in wireless sensor networks using fuzzy logic control

In general, environment monitoring cluster based hierarchical routing protocol is among the most common protocol being opted due to the load balancing among each other sensor. Sensors are randomly deployed in a specific area to collect useful information periodically for a few months or even a few years. Therefore, battery power limitation becomes a challenging issue. It is also impractical to maintain the network lifetime by changing the battery frequently. Low energy adaptive cluster hierarchical (LEACH) is one of the common clustering protocols that will elect the cluster head based on the probability model which will possibly lead to a reduce in network lifetime due to election of cluster head with a least desired location in the network. For wireless sensor networks, the distribution of cluster head selection directly influences the networks lifetime. This paper presents factors which will affect the network lifetime and apply fuzzy logic based cluster head selection conducted in base station. The base station considers two selection criteria from sensor nodes which are energy level and distance to the base station to select the suitable cluster head that will prolong the first node die (FND) time, data stream guaranteed for every round and also increase the throughput received by the base station before FND.

Adaptive hybrid channel assignment in wireless mobile network via genetic algorithm

In wireless mobile network, the challenge is to assign appropriate frequency spectrum channels to requested calls while maintaining a desirable level of electromagnetic compatibility (EMC) constraint. An effective channel assignment technique is important to improve the system capacity and to reduce the effect of the interference. Most of the existing channel assignment approaches are based on deterministic methods. In this paper, an adaptive hybrid channel assignment (HCA) technique based on genetic algorithm (GA) is proposed. The proposed GA based optimization in HCA scheme is capable to adapt the population size to the number of eligible channels for a particular cell upon new call arrivals in order to achieve faster convergence speed. Besides, the proposed approach can handle both the reassignment of existing calls as well as the allocation of channel to a new call in an adaptive process to maximize the utility of the limited frequency spectrum. The simulation for both uniform and nonuniform traffic distributions on a 49-cells network model show that the average new incoming call blocking or call dropping probability for the proposed hybrid channel optimization method is lower than the deterministic HCA methods.

Analysis and performance measurement of adaptive modulation and coding

Wireless spectrum is considered a limited and valuable communications resource as it influences productivity, security and our daily lives. The usage of the wireless spectrum has been given much research focus due to its limited capacity. There is currently a large amount of white spaces and spectrum holes left unused. Therefore, researchers are motivated to invent methods to utilize the spectrum more efficiently and opportunistically. Adaptive modulation and coding (AMC) is a method which adapts its transmitting parameters according to the channel state and it is used in various modern wireless communications to maximize spectrum efficiency and minimize error rate. One of the driving strengths of AMC is the Signal-to-Noise Ratio (SNR) estimation and feedback channel for adaptation. Sudden time-varying channel degrading effects sometimes require the transmission link to react appropriately so it can minimize the Bit Error Rate (BER). Thus, the objective of this paper introduces an AMC scheme which utilizes a simple moments based SNR estimator and punctured convolutional coding for spectral and quality improvement for the wireless channel.

Design and development of a tablet based real time wireless data logger

To date, data loggers are getting more implementation in business and home applications compare with several years ago. Data loggers can be customized according to the application requirement based on the available resources in the market. Thus, this creates a cost effective solution for the end user. In this paper, a wireless data logger with remote control capability via PC and tablet is introduced. The proposed wireless data logger is developed using microcontroller with analog-to-digital converter (ADC). The design of the portable wireless data logger is compact and light to increase the mobility and usability. Sampled data with time stamp from real time clock (RTC) module will be stored into SD memory card which is attached to controller board. Wireless data logger can directly transmit the data to end user if the device is in the communication coverage or stored the data into memory card if it is out of range. Graphic user interface (GUI) developed using Visual Basic and Android application. These applications can communicate with wireless data logger through wireless XBee module and Bluetooth module. End user can change the data logger settings such as, data sampling frequency, date and time remotely.

Minimizing Network Coding Nodes in Multicast Tree Construction via Genetic Algorithm

Network coding is a method that increases network throughput by encoding several packets with single packet size length and forwards the packet in a single transmission time slot. At the same time, network coding increases the complexity of packets management and delay of network due to the waiting time for network coding opportunity. A solution based on improved genetic algorithm is proposed to optimize the network coding node resources in network coding. Genetic algorithm will search a multicast tree that fulfils the desired throughput with a desired multicast rate. Mutation rate of the genetic algorithm will change based on the previous solution to avoid from being stuck on the local optima. The simulation result shows that with given multicast rate, improved genetic algorithm is able to search and construct multicast tree with minimal usage of network coding nodes.

Development of a wireless device control based mobile robot navigation system

Tablets are highly functional and flexible platforms to pair with robotic autonomy and navigation control. The advantage of remotely controlling robots using mobile devices is location independence. New research is merging towards more applications for mobile devices and robotics. Specifically, more emphasis is given to the communication technology that connects mobile devices with robots. In this paper, the design and development of a mobile robot system with tablet is presented in detail. The wireless communications interfaced between the microcontroller, computer and tablet is described. The user is able to navigate the mobile robot to travel through points of interest via a GUI interface on the tablet.

Performance Measurement of Evolutionary Routing Protocol in Network Coding

Wireless networks are suffer from throughput limitation, one of the effective method to solve limitation of wireless throughput are network coding which is combine several packets from difference input to a single packet size length and forwards the packet in a single transmission time slot. Furthermore, network coding also reduce energy usage in wireless devices. However, while network coding improve throughput of network it also introduce side effect such as increasing on buffer capacity and delay. In this paper, an evolutionary approach is proposed to optimize the advantages and disadvantages of network coding in a network. The simulation result shows that evolutionary algorithm is able to search multipath with minimal usage of coding nodes to balance the overhead and throughputs of network.

Node collaboration for distributed beamforming in wireless sensor networks

Collaborative beamforming (CB) is introduced in wireless sensor networks (WSNs) to improve the transmission power and the energy efficiency of the networks. Using a subset number of nodes from a network of sensors, they collectively transmit a common message with different proper weights to an intended location. Different geometrical location of the subset of nodes will produce different transmission gains. Due to erratic deployment of the sensor nodes in the networks, the assignment for the sensor nodes in wireless sensor networks is vital to achieve better array pattern synthesis. In this paper, a node selection method based on uniform circular array is presented. Simulation and performance analysis are carried out to demonstrate the beam pattern performance of uniform circular in performing collaborative beamforming.

Performance analysis of utilizing coding nodes in wireless networks

Network Coding is a method that effectively combines several packets from different sources and broadcasts the combined packet to several destinations in single transmission time slot. Each destination is capable to extract the intended information by decoding from a common packet. In short, network coding is a method that improves the throughput for wireless networks and wired networks. However, while it increases the throughput of networks, it also causes side effects such as complexity of packets management and increased delay for coding opportunity. In this paper, genetic algorithm is proposed to optimize the resources for network coding. Genetic algorithm will search for suitable routes to the destination according to the desired throughput with a desired multicast rate. The simulation results show that the average end to end delay of network after minimizing coding nodes is less than normal network coding.

Adaptive modulation in public transport network system with network coding

The complexity and function of transportation are evolving following the advancements in technology. This phenomenon is correlated to the needs of transportation users and also the requirement to develop new and safer transportation which will ease the commuting process. Using communication technology, transportation systems gain an added advantage on top of its conventional purpose. The technology of communications and computing embedded into transportation branches into a field named Intelligent Transportation Systems (ITS). To enable such frameworks, the communication support infrastructure has to be well defined and planned systematically. The integration of communication into transportation systems and vehicles helps broadcast information to help the driver make informed decisions. Users of transportation can also benefit from the updated information regarding routes and options to travel. Besides that, the introduction of wireless sensors will help autonomous systems facilitate public transportation. This paper describes a framework to address the challenges in public transportation service in campus, more specifically, to improve the smoothness and reliability of service. The communication network can improve the overall efficiency and bring comfort to travelers.