Micheal Drieberg

Development of vehicle tracking system using GPS and GSM modem

The ability to track vehicles is useful in many applications including security of personal vehicles, public transportation systems, fleet management and others. Furthermore, the number of vehicles on the road globally is also expected to increase rapidly. Therefore, the development of vehicle tracking system using the Global Positioning System (GPS) and Global System for Mobile Communications (GSM) modem is undertaken with the aim of enabling users to locate their vehicles with ease and in a convenient manner. The system will provide users with the capability to track vehicle remotely through the mobile network. This paper presents the development of the vehicle tracking systems hardware prototype. Specifically, the system will utilize GPS to obtain a vehicles coordinate and transmit it using GSM modem to the users phone through the mobile network. The main hardware components of the system are u-blox NEO-6Q GPS receiver module, u-blox LEON-G100 GSM module and Arduino Uno microcontroller. The developed vehicle tracking system demonstrates the feasibility of near real-time tracking of vehicles and improved customizability, global operability and cost when compared to existing solutions.

Reader to reader anticollision protocols in dense and passive RFID environment

A dense radio frequency identification network, consists of several readers located in close proximity to improve coverage and read rate. In such environment, reader to reader collision (RRC) is a common and inevitable problem. Although a number of algorithms has been proposed to mitigate these collisions, most of them require extra hardware, do not make an effective use of the network resources or they are incompatible with the current standards and regulations. This paper reviews the significant proposals for anti-collision of RFID readers, coordination in passive and dense reader environment (DRE). The short comings and incompatibilities with the state of the art standards like EPCglobal Class-1 Gen-2 are also discussed. Finally, research directions to improve the current RRC approaches are presented.

On PAPR Reduction in OFDM Systems: A Technique using Normalized Complex Hadamard Transform

A new technique for the reduction of peak to average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems is presented. It is based on preceding the constellation symbols with normalized complex Hadamard transform (NCHT). The proposed technique can achieve about 3 dB more reduction in PAPR compared to conventional OFDM systems. The technique has been shown to be effective and has low complexity.

DWT based FFT in Practical OFDM Systems

OFDM is a multi-carrier technique based on a very simple modulation scheme that uses IFFT and FFT at its core for transmission and reception respectively. The performance of the OFDM receiver is significantly affected in the presence of noise in the wireless channel. In this work a receiver that has built-in denoising capacity with little additional computation is proposed. lt is based on a DWT based FFT algorithm. Experiments using MATLAB are conducted to verify the feasibility of this denoising algorithm on OFDM signals. The result shows noise suppression thus supports our claim

A simple channel estimation method for MIMO-OFDM in IEEE 802.16a

Both orthogonal frequency division multiplexing (OFDM) and multiinput multioutput (MIMO) are generic techniques that are being actively considered for applications in 4G mobile. In MIMO applications, the channel between each pair of transmitter and receiver needs to be estimated accurately for coherent demodulation and space-time (ST) codes decoding to work optimally. In this work, we propose a simple channel estimation method for a MIMO-OFDM system based on IEEE 802.16a (wireless Metropolitan Area Network (MAN)). The method works by cyclically rotating the same preamble at each transmitter by a different number of samples in such a way that the channel impulse response (CIR) of the channels from each transmitter can be separated in time. Using just simple processing at each receiver, the CIR of the respective channels from each of the transmitter can be separated and their estimates obtained. The estimation method has been tested extensively in simulations of 2/spl times/2 MIMO-OFDM system based on IEEE 802.16a standard developed in Matlab/Simulink. The ST code used is Alamoutis ST Block Code which gives very good performance and is quite simple to implement. Results show that the overall system BER are nearly as good as the upper bound performance that is obtained with perfect channel state information (CSI).

Route optimization of feeder bus for Electric Train Service

The Electric Train Service (ETS), which connects the cities of Kuala Lumpur and Ipoh, has been in operation since 2010. The ETS has not only provided a safe, fast and cost effective way to travel between these two cities, but has also spurred the economic activities of the major towns between them. However, the lack of an effective feeder bus system that brings commuters to the ETS stations remains a significant problem. The objective of this paper is to design a wide coverage feeder bus route that is also effective and efficient in terms of service. Specifically, genetic algorithm has been used to optimize the feeder bus route. The optimization is performed to attain the widest service coverage, lowest operation cost, shortest total travel time, shortest total travel distance and to meet the highest demand. As a test case, the Batu Gajah, Perak ETS station has been used. Simulation results show that solving the route optimization problem can produce a wide coverage route with high effectiveness and efficiency in service.

A Dynamic Blocking Notification (BN) Scheme with Strategic Nodes for Wireless Ad Hoc Networks

The traditional RTS/CTS handshaking has been widely adopted in wireless ad hoc networks to reduce the hidden terminal problem. However, the handshaking induces the false blocking problem where adjacent nodes are deferred unnecessarily by overhearing the unsuccessful RTS packets. To mitigate these, the Blocking Notification (BN) scheme was proposed previously. In the BN scheme, the hidden and exposed receivers will broadcast the BN packets to inform adjacent nodes of their deferring status to avoid any incoming RTS packets which will not be replied by them. Nevertheless, the BN scheme itself can potentially incur redundant BN packet transmissions, energy wastage and packet collisions. The effectiveness of the BN scheme depends critically on the judicious transmission and successful reception of BN packet. In this paper, we propose an improved BN scheme that is able to dynamically assign strategic nodes the right to broadcast the BN packets. The improved BN scheme with strategic nodes attempts to minimize the BN packet transmissions and avoid collisions while maximizing their successful receptions at the intended nodes. This ensures higher energy efficiency, which is critical in ad hoc networks. Moreover, the proposed BN scheme can be deployed in any arbitrary network topology instead of a simplistic linear topology as assumed in previous works. Simulation results have shown that the proposed BN scheme with strategic nodes can significantly reduce the number of BN packet transmissions and provide energy savings of up to 60%.

Probabilistic polling MAC protocol with unslotted CSMA for wireless sensor networks (WSNs)

Wireless sensor networks (WSNs) may lead to high traffic in network when nodes detect an event and become active to send the data to the sink. Therefore, traffic adaptive medium access control (MAC) protocol for WSNs, with a more strict collision avoidance technique, can help in resolving the issue of collision by allowing less number of sensor nodes to send the data on the shared wireless channel. Probabilistic polling is a receiver-initiated MAC protocol proposed for energy harvesting wireless sensor networks (EH-WSNs), with a channel access mechanism known as contention probability. In this mechanism the receiver sets a pre-condition for the nodes who want to relay their packets to the receiver. Node that satisfies the condition can send their data packets. In this paper, the performance of probabilistic polling protocol for battery powered wireless sensor networks (BP-WSNs) is studied instead of EH-WSNs. Also unslotted CSMA probabilistic polling (UCSMA probabilistic polling) protocol is proposed that uses the contention probability along with un-slotted CSMA/CA as channel access mechanism. The simulation results show that UCSMA probabilistic polling protocol can improve the network performance in term of high throughput and fairness.

A simulator based study to evaluate driver drowsiness using electroencephalogram

Preventing accidents due to drowsiness at the wheel has been an area of extensive research in the past few years because of the severity of the problem. For this purpose, continuous observation of physiological signals of the driver provides the possibility of detecting drowsiness. A simulator based study is conducted to evaluate driver drowsiness using electroencephalographic (EEG) signal. Twenty two healthy subjects voluntarily participated in the experiment. Relative power of each EEG frequency band is computed by taking the FFT of time domain signal using Welchs method to observe the spectral variation from alert to drowsy state. Topographic maps are used to visualize the spectral changes that occur in each power band. Results show that the relative power of theta and alpha bands exhibit significant changes in drowsy state and these changes are more dominant in the occipital and parietal regions of the brain.

Low PAPR preamble for IEEE802.16a OFDM system

Orthogonal frequency division multiplexing (OFDM) is a key enabling technology for future wireless communications systems. OFDM makes equalization simple and effective. However, accurate channel estimates are necessary at the receiver for the optimum operation of OFDM systems. Channel estimation usually employs some form of training signal, also known as the preamble, in the front of the packet. It is desirable to have a preamble signal with the lowest peak-to-average power ratio (PAPR) so that the estimation signal to noise ratio (SNR) can be maximized. In this work, we address the problem of designing very low peak-to-average power ratio (PAPR) preamble for orthogonal frequency division multiplexing (OFDM) systems. The initial preamble is designed using generalized chirp like (GCL) sequences. In order to obtain the lowest PAPR, the preamble is optimized using constrained nonlinear optimization technique. Results show that the proposed preamble has a PAPR of just 0.871 dB that translates into a gain of 2.129 dB when compared to the prescribed preamble of IEEE 802.16a standard that has a PAPR of 3 dB.