Mardeni Roslee

Feasibility study of LTE signal as a new illuminators of opportunity for passive radar applications

Recently, there has been an evolution of mobile networks towards the fourth generation radio wireless communications (4G) as LTE (Long Term Evolution). In this paper, the feasibility of using LTE-based passive radar is investigated to take advantage of using LTE signal as illuminator of opportunity for moving object monitoring. An analysis of ambiguity function is done on a typical LTE waveform to assess the Doppler and range characteristics. The initial results and analysis show that LTE signal range and Doppler resolutions of 7.5m and 0.11m/s can be achieved, respectively.

Design of bow tie antenna in CST studio suite below 2GHz for ground penetrating radar applications

This paper explains how a bowtie antenna is to be designed for ground penetrating radar (GPR) applications. The considerations to be taken into account include to design the smallest antenna possible for low frequency range (below 2 GHz). This is because the test equipment used, Vector Network Analyzer by Agilent Technologies can only work up to 3 GHz. Bowtie antenna is chosen because it has better directivity compared to other antennas such as horn, and it is easier to fabricate using microstrip boards which are available in the university. At the end of the design, the operating frequency range is determined and the design is fabricated to be used for measuring samples like soil and concrete.

Analysis of spectrum handoff schemes in cognitive radio network using particle swarm optimization

Cognitive radio (CR) is an intelligent technique which is used to improve the spectrum utilization through four main functions: spectrum sensing, spectrum decision, spectrum sharing and spectrum mobility. In this paper, we focus on spectrum mobility (or called spectrum handoff) that occurs when the primary users (PUs) appear to occupy its licensed band that used by secondary users (SUs). We discuss the three spectrum handoff mechanisms that used to reduce the handoff delay (proactive, reactive and hybrid). We implement particle swarm optimization (PSO) to minimize the total service time of spectrum handoff to the optimal value. Numerical results show that PSO is significantly minimizing the total service time compared to other spectrum handoff schemes.

Fuzzy logic based negotiation approach for spectrum handoff in cognitive radio network

Cognitive Radio Network (CRN) is a new technique that utilizes available unlicensed spectrum bands due to limited numbers of fixed licensed spectrum bands. It consists of four main functions, namely, spectrum sensing, spectrum decision, spectrum sharing and spectrum mobility. We focus on the spectrum mobility (also known as spectrum handoff) which manages the movements of secondary users to occupy the vacant unlicensed spectrum without interrupting the transmission of primary users. In this paper, we introduce fuzzy logic based negotiation approach based for spectrum handoff in CRN. It contains two Fuzzy Logic Controllers (FLCs), namely, price negotiation and duration negotiation. The proposed system provides a good solution to avoid the communication interruption caused by the mobility of SU. It will reduce the handoff delay by 46 ∼ 62% if the SU correctly selects the best PU.

Implementation of RFID and bluetooth technology for data tagging and transmission to point of sale

The design of wireless technology which involves radio frequency identiflcation (RFID) and Bluetooth technology for tagging and transmission of data that will be applied to point of sale (POS) is presented. A complete POS circuitry system has been designed to allow certain item to be a tag easily identifled and localized. This is implemented by using RFID technology which will communicate with personal computer (PC) either through Ethernet or Wifl connection. An Impinj RFID reader and Bluetooth mobile phone are selected in the proposed POS system. Matlab simulation has been performed for RFID transceiver part and Bluetooth data transmission. A prototype software is developed to interface the Impinj RFID reader through the Ethernet connection. Additionally, a data encryption from Bluetooth is paired with PC to achieve a secure and simple pairing feature when customer transaction is performed. It involves hardware and software implementation. Moreover, in simulation result, a double side band modulation is used to design the RFID reader for better item tagging. The results show the feasibility of using this design for POS and achieving very good read ranges. Finally, Bluetooth system enables fast transaction and makes purchase securely by using the proposed asymmetric algorithm.

Efficient handoff spectrum scheme using fuzzy decision making in cognitive radio system

Cognitive Radio Network (CRN) is a new technique that utilizes available unlicensed spectrum bands due to limited numbers of fixed licensed spectrum bands. It consists of four main functions, namely, spectrum sensing, spectrum decision, spectrum sharing and spectrum mobility. We focus on the spectrum mobility (also known as spectrum handoff) which manages the movements of secondary users to occupy the vacant unlicensed spectrum without interrupting the transmission of primary users. In this paper, we introduce spectrum handoff based on the fuzzy logic system. The proposed system consists of one Fuzzy Logic Controllers (FLC) with three input linguistic variables, namely, received power, eNB load and arrival rate of PUs and one linguistic variable (handoff probability). The proposed system provides a good platform to avoid unwanted handoff in CRNs in LTE-A system.

A Novel of Surface Reflection Method Using Radio-Wave for Soil Density Estimation

Soil density is one of the important parameters to be investigated in civil, geological and agricultural works. Unfortunately, the challenging issue is found on a suitable model in determining accurately the soil density. In this article, a new soil density model based on radio-wave surface reflection method is presented. The development of the model is based on result analysis collected from the experiment. Then, comparisons with related theoretical models, Hallikainen and Topp, are performed. The experiment is performed by using a vector network analyzer (VNA) that generates radar signal and recording return loss (S11) from a horn antenna. In the analysis, two new proposed soil density models have shown good agreement for soil density from 1.1 g/cm 3 to 1.7 g/cm 3 for sand and silty sand samples. This is verified when the model able to predict real samples as the one used in the experiment and result shows a very small relative error within 0.05% and 6.87%. Additionally, spectrograms in real time are produced in this study in order to observe more on the soil density. By using the proposed developed models, soil density estimation can be easily determined with minimal data input such as soil type, return loss and reflection coefficient by using regular radio-wave devices.

WRAN system on ZBC TV: A new way to internet connectivity for rural areas in Zimbabwe

Wireless Regional Access Network (WRAN) is increasingly becoming the focus architecture for future rural and remote areas access network. In Zimbabwe, internet connectivity to the rural areas is crucial but is hindered by what is called the Zimbabwean problem. In this paper brief discussions of existing technologies deployed for rural communications elsewhere in the world and recent technologies such as cognitive radio (CR) networks are explored for solutions to the Zimbabwean problem. In the process, WRAN, which exhibits extended coverage range, increased cell capacity and utilises idle TV spectrum and saves on deployment costs, was identified as a suitable broadband access candidate for providing connectivity to the rural areas of Zimbabwe. A design network structure is proposed and a basic CR simulation in MATLAB, and employing, power spectrum density estimation model for sensing, to show the possibility of harnessing idle Zimbabwe Broadcasting Corporation (ZBC) TV channels using CR technology is successfully run. A number of implementation challenges such as the effect of antenna height on the hidden terminal problem, MIMO incorporation in order to mitigate for such effects in WRAN networks, the investigation and mitigation of interference contribution from remote television stations, WRAN networks and other primary stations and users are discussed.