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Due to the increasing numbers of vehicles in the world which results in a rise in traffic density, smart city is seeking to minimize transportation problems such as accidents. To solve this issue, VANET has been developed to improve vehicles’ mobility and provide a safe city. VANET is a type of wireless technology which provides vehicle-to-vehicle (V2V) and vehicle-to-infrastructures (V2I) communication system. Despite the advantages of VANET, it faces a lot of challenges; security and privacy, for instance, are the most critical ones. In this paper, we implement an approach used in Optical CDMA system given its success in optical domain. This technique is based on the 2D ZCC/MD code which is characterized by zero cross-correlation property. The transmission system is based on the VLC system, in which the information will circulate in optic domain using light in free space. The proposed system can provide the security and the privacy due to the 2D ZCC/MD code which assigns each user by a specific unique code.

Visible light communication (VLC) technology offers unregulated, unlicensed and huge bandwidth to meet the growing demand in future indoor communication system. One of the major challenge in VLC system is in improving transmission speed with optimize the bandwidth capacity. The method to improve spectral usage is using advanced modulation formats such as orthogonal frequency division multiplexing (OFDM). In this work, a new approach for modulation technique based on multiband OFDM has been developed which capable to improve the spectral efficiency and optimize the data rate. A proposed technique is then adapted in OCDMA-VLC environment to analyse the reliability of the proposed scheme in high capacity network. Different selection of parameter values such as bit rates, number of bands and effective received power will have different effect on the system performance. Numerical result shown that the catenated-OFDM outperforms conventional OFDM by five times spectral efficiency improvement and eight times spectral efficiency improvement at their five and eight number of bands respectively. It is also shown that the proposed catenated-OFDM design is working well even at very high bit rate of 15 Gbps. Moreover, there are enhancement in receiver sensitivity with 7.3 dB power penalty compared to previous work.

In this paper, we show details of zero cross correlation (ZCC) code development and investigate performance by measuring bit-error-rates compared to other optical code division multiple access (OCDMA) codes using Avalanche photodiode (APD) and PIN photodetector. We present a configuration to determine how optical OCDMA systems can be applied with PIN and APD photodetector. Analysis of Avalanche photodiode gain optimization is discussed in ZCC code system. We also present analytical and numerical theoretical results for data transmission of spectrally encoded incoherent OCDMA signal and how signal-noise is being affected by using these two photodetectors.

This paper presents a development of microstrip dual-band bandpass filter for Industrial, Scientific and Medical (ISM) band application. The proposed bandpass filter which can operate at 2.4 GHz and 5 GHz band is implemented based on parallel coupled line technique. The parallel coupled line filter allows tuning two bands at desired frequencies apart for minimizing the return losses within both dual passband. The Advanced Design System (ADS) simulator has been used during simulation and optimization. For the design verification, the prototype of the proposed microstrip filter has been fabricated and measured. The simulated return loss S11 and insertion loss S21 of the proposed microstrip filter are −25.092 dB and −0.013 dB at 2.4 GHz respectively, while −22.373 dB and −0.025 dB at 5 GHz respectively. For the design verification, the prototype of the proposed antenna was fabricated and measured. The result shows that the proposed design can be realized in any communication system applications.

A new dual-diffuser modulation (DDM) technique improve the performance of the conventional intensity modulation/direct detection (IM/DD) for On Off Keying (OOK) in term of data bit rate and propagation distance. This new modulation technique employs two transmitters and two receivers to create a robust modulation with optimizing the reduction scintillation index, enhance the power received and improve the threshold signal level. At the transmitters, the laser exits combine with low cost phase screen diffuser to create a ‘new’ superior laser beam characteristic in order to combat atmospheric turbulence effectively. Meanwhile at the receivers, the signal will be subtracted. The analysis result shows that in comparison various data bit rates at BER10−9, the DDM is capable to operate excellent under small power launched where the bit rate can achieved above 10Gbps at 5dBm power transmit. Meanwhile for phase screen diffuser effect, the DDM optimizes the performance of diffuser where the data bit rate can reached approximately 1.5Gbps and the conventional IM/DD-OOK only performed at 0.155Gbps.

Dense wavelength division multiplexing system is a system for coupling and transmitting the optical signals at different wavelength through the single fiber. Such technology is important in order to increase the capacity in optical communication system and to meet the growing demands of bandwidth. However, there are some limiting factors related to the data rate and capacity in this system. These limiting factors can be linear or nonlinear. Theoretically, the nonlinearities in fiber arise as the number of data channel, transmission length, data rate and input power level increase. In this project, the objective is focused towards analyzing on the nonlinearities effect by compensating the linear effect in the fiber. Dispersion Compensation Fiber (DCF) and linear loss EDFA compensation have been used in single mode fiber (SMF) channel to ensure the communication quality for the design. The proposed dispersion compensation DC-DWDM transmission system with 16 and 32 channels for 10Gbps with a channel spacing of 0.8nm was designed and simulated. The BER performance with various input power levels in the range of −10dBm up to 10dBm, and fiber length greater than 50km are analyzed. It has been shown that for fixed length of the fiber, the only variable that can be manipulated to lower the nonlinear contribution is the input power. The higher the input power the higher the nonlinear contribution. However, if the input power is low, the bit rate should be low to maintained transmission at the expected BER (BER < 10–12)

This paper proposed a new design of a 2.45 GHz harmonic suppression circularly polarized microstrip patch antenna. The purpose of harmonic suppression antenna is to eliminate the using of harmonic filter circuit in a rectenna system as well as for the others active integrated antenna (AIA) applications. By introducing a defected ground structure (DGS) technique with a back-to-back U shape slot, the magnitude of the return loss at the harmonic frequencies are suppressed successfully. The patch antenna is designed on an FR4 substrate with e r =4.7 and a thickness of 1.6 mm have −28dB return loss at 2.45GHz and suppress the second and third harmonic up to −0.8dB and −1.8dB respectively.

This paper presented a new design of harmonic suppression microstrip patch antenna with the circular polarization properties at frequency 900MHz for an RF ambient energy harvesting system. The purpose of harmonic suppression antenna is to eliminate the using of a harmonic filter circuit in filtering the unwanted signal at the harmonic frequencies in a rectenna system. By introducing a truncating to corner of the rectangular microstrip patch antenna to achieved the required axial ratio, an antenna with circular polarization property is presented. The dimension of patch is reduced by applying partially ground plane. Then an implementation of a defected ground structure (DGS) with a circular shape slot, the unwanted radiation at harmonic frequencies are successfully suppressed. The patch antenna is designed on an FR4 substrate with er=4.7 and a thickness of 1.6 mm has -20dB return loss at 900 MHz and suppress the second and third harmonic up to -2dB. The proposed circularly polarized harmonic suppression antenna is then fabricated and measured for the verification of the design.

In this paper, we propose a novel 2D spectral/spatial hybrid code based on 1D ZCC and 1D MD where the both present a zero cross correlation property analyzed and the influence of the noise of optical as Phase Induced Intensity Noise (PIIN), shot and thermal noise. This new code is shown effectively to mitigate the PIIN and suppresses MAI. Using 2D ZCC/MD code the performance of the system can be improved in term of as well as to support more simultaneous users compared of the 2D FCC/MDW and 2D DPDC codes.

This paper presented a new design of rectangular patch antenna which is able to suppress the harmonic frequencies. The techniques that are used in the suppression of harmonics are a notch-loaded and curvature slots at the antenna patch together with an open stub and inset feed transmission line. The partially ground with a circular slot at ground plane is also introduced to reduce the overall patch size. The patch antenna is designed on an FR4 substrate with e r =4.7 and a thickness of 1.6 mm give −40dB return loss at 2.45GHz and suppress all the harmonics up to −1dB. The proposed of harmonic suppression antenna can avoid by using harmonic filter circuit in the rectenna circuit and active integrated antenna (AIA) applications, thus the system becomes compact and cheaper.

This paper proposed a new circular patch antenna design with harmonics suppression capability. The purpose of harmonic suppression antenna is to eliminate the use of harmonic filter circuit in rectenna circuit. By introducing slits at the antenna patch and stub at the transmission line, unwanted harmonics frequencies are successfully suppressed. In addition, the size of proposed circular patch antenna is reduced by using partial ground and circular slot technique at the ground plane. The patch antenna is design on FR4 substrate with e r =4.7 and a thickness of 1.6 mm has −48dB return loss at 2.45GHz and suppress the second and third harmonic up to −3dB. The proposed harmonic suppression antenna can be applied in rectenna and active integrated antenna (AIA) applications, thus the circuit become compact, cheaper and more efficient.

In this paper, we demonstrate a novel architecture of variable weight Zero Cross Correlation code in the family of Spectral Amplitude Coding(SAC) Optical Code Division Multiple Access (OCDMA) to be utilized in the triple play services of OCDMA applications based on the end users demand and requirements. This is achieved by adapting multiple weights of Zero Cross Correlation (ZCC) code onto one system to accommodate different Quality of Service (QoS) requirements. The results are characterized by bit error rate (BER) and eye pattern simulated using OptiSystem software. Results proved a successful transmission of this scheme over 20km distance thus offering flexibility of independent QoS. It is also revealed that the performance is always better for users with larger number of code weight compared to those assigned with smaller code weight.

In this paper, an improvement of achievable system capacity Avalanche photodiode (APD) performance of spatial/spectral modified double weight (MDW) code for cardinality, bit error rates (BER) and noise interference is analyzed. The results in very good agreement indicate that 61% cardinality improvements compare to 2-D MDW code with PIN. The effective transmitted power (P sr ) for 2-D MDW-APD (M=135, N=3) improves by 8.5dBm at 10−9 error floor. At low gain BER value is mitigated through suppressing PIIN. Apparently, performance of the proposed system improves substantially with APD.

In this paper, a feasibility study of the ambient radio frequency (RF) as an energy source to be harvested and converted into electrical energy is presented. This study is to investigate the ability to harvest the ambient RF power density produced by the GSM telecommunication tower for very low power device usage. To capture the RF signal, a normal mode helical rectenna is designed and fabricated. The reason of choosing the normal mode helical antenna in this study is to solve the major problem of a microstrip patch antenna array where the overall size is very large. Experimental results showed that with −10dBm input power, a voltage of 0.3V is generated at the distance 2.5 meters. Hence, this proved that the ambient RF energy can be a suitable candidate as an energy harvesting source.

In this paper, the implementation of subcarrier multiplexing technique in spectral amplitude coding (SAC) optical code division multiple access (OCDMA) network using Zero Cross Correlation code is developed and investigated. Theoretical analysis is done to determine the signal-to-noise ratio of such network and analysis of the performances in term of bit error rates are presented. Simulations are done using Optisys software version 6.0. Motivation to this research is driven to take advantage of both the low implementation cost of the SCM technology which uses the existing RF/microwave devices; and the attractive SAC which reduce the Multiple Access Interference (MAI) in OCDMA system. The use of ZCC code can eradicate phase induced intensity noise (PUN) which will contribute to better BER. For typical error rate of optical communication system of 10e-9, it has been observed fro theoretical results that the new hybrid SCM/OCDMA system provide better spectral efficiency and accommodate more users simultaneously with less code length and thus lower cost of implementations than the traditional OCDMA network utilizing the ZCC code. Thus this system could be one promising solution to the symmetric high capacity access network with high spectral efficiency, cost effective, good flexibility and enhanced security, which makes an attractive candidate for next generation broadband access network

This paper is to provide the preliminary result and activities of a research program at UNIMAP on rain attenuation in the Perlis region. The project uses the LaserBit product; model LB-2500 and LB-5000 which can maximum reach 2500 m and 5000 m with wavelength 785 nm and laser power 70 mW. The result will utilize four existing model rain attenuation and measured data will compared to calculated result to determine the validity of precipitation model and deepen the consequence of rain intensity. As additional to unwavering the measurement. Optisys software has been used to simulate the data to predict the possibility of result.

MIMO technology has attracted a lot of attention in the area of wireless communications such as radar applications, in term of increasing the spectral efficiency. This research paper will present the model of Simulated Radar Emission Environment for RWR testing using MATLAB. For the first phase of the research, the radar emission environment is modeled by modeling four directions of signals as continuous wave with different amplitude to represent their emission of power. These four directions are a distribution of 360 degrees from the aircraft. These signals are propagated through their own transmission channel, showing that they are coming from four different propagation transmissions. A LMS equalizer has been adopted to equalize and analyze the incoming signal. The main purpose of this research is to find an alternative way of testing the radar warning receiver in an indoor approach rather than taking a costly outdoor testing session from the aircraft.