nan Sugihartono

Interpretation target pattern of a buried basic object on Surface Ground Penetrating Radar system

Surface Ground Penetrating Radar (GPR) is the one of Radar technology that is widely used on many applications. It is non-destructive remote sensing method to detect underground buried objects. However, the output target is only hyperbolic representation. This research tries to enhance GPR capability by representing the visual/pattern of the detected target. GPR data of many basic objects (with circular, triangular and rectangular cross-section) are classified and extracted to generate data training model as a unique template for each type basic object. The pattern of object under test will be known by comparing its data with the training data using a decision tree method. A simple powerful algorithm to extract feature parameters of object which based on linier extrapolation is proposed. The result shown that tested buried basic objects can be correctly interpreted.

A Jarque-Bera test based spectrum sensing for cognitive radio

A cognitive radio has to perform spectrum sensing to detect the vacant channel. The detection faces some challenges due to the required performance and limited knowledge on the primary signals and the channel. In this paper we proposed a blind spectrum sensing method for cognitive radio network. The proposed method based on the difference on distribution of the condition between when the transmission from primary user is active and when its inactive. If it is inactive, the received signal will contain only noise. The distribution of noise which is Gaussian, differs from the distribution of signal which is contaminated with noise. The Jarque-Bera (JB) test is used for the detection of the event. The target of the analysis is both the real and the imaginary parts of FFTs output. The proposed algorithm was tested to detect the DTV signal. Results show that our method is performed better than previous similar method.

Crosstalk analysis of parallel microstrip line using 4-port scattering model

The development in wireless communication indirectly gives impact on complexities of electronics circuit design both in the transmitter and receiver. One of the complexities is PCB trace design. Designer, as one of the considerations, has to estimate crosstalk between trace carefully. This paper proposed a method to estimate crosstalk using scattering matrix. A parallel microstrip line deployed on FR-4 dielectric substrate with ground plane has been modelled and simulated. First scenario, a parallel microstrip line was modelled in straight form. For the second, a parallel microstrip was modelled in bending form. The simulation result shows that crosstalk in term of reflected voltage tend to increase with frequency. But, there was an anomaly, certain frequency give a minimum crosstalk. Crosstalk decrease when the distance between separated lines increased.

Comparison of decoding algorithms for LDPC codes of IEEE 802.16e standard

One of forward error correction codes that were defined in the IEEE 802.16e standard was the LDPC code. This paper presents the simulation of the LDPC codes using three decoding algorithms, i.e. sum-product algorithm, min-sum algorithm, and min-sum-plus-correction-factor algorithm. Simulation results show the decoding with sum-product algorithm and min-sum-plus-correction-factor algorithm provide BER performances better than the min-sum algorithm.

Performance evaluation of Ka-Band satellite communication system in rain fading channel at tropical area

Generally, commercial satellites use C-band and Ku-band, but because of the rapid growth of satellite services and congestion of lower frequencies bands, more and more commercial applications are being promoted for Ka-Band. In order to use Ka-band for satellite communication in tropical areas, there are several issues that have to be considered. One of the disadvantages of Ka-band is it is susceptible to be attenuated by rain and the earths atmospheric conditions such as gas, clouds, and ice particles. This paper is aimed to evaluate the performance of Ka-band wireless communication system in tropical area by comparing several channel coding schemes.

A Novel MC-CDMA Multilevel Coding Scheme on High Data Rate MIMO-Wireless Communication Systems

Wireless broadband access system will operate in high mobility and high data rate environment It is necessary to consider a system that is applied with or without perfect channel information, having more spectrum efficiency, and mitigating selective fading problems. We propose an MC CDMA multilevel coding system model that capable to solve those problems. We consider to this system accommodate various bandwidth usage, QoS or channel response for every user. From the research results, it is concluded that in general the MC CDMA multilevel coding scheme will provide a good performance with high speed user in non coherent channel transmission scheme.

Characterization of radar absorber based on square patch textured surface

A square patch can operate whereby at the resonance frequency of resistively textured surface. The surface behaves like a perfect magnetic conductor; therefore the electric field would be in tangential to the surface. The developed patch that consists of square shape of metallic copper with length of 22mm and gap between patches of 2.0mm is placed on a single-sided 3.2mm thick grounded FR4 Epoxy dielectric substrate. Relative permittivity and tan δ of the dielectric substrate are 4.04 and 0.02, respectively, whilst the thickness of metallic copper top patch as well as the ground plane is 0.035mm. The losses of dielectric substrate and copper conductive are also taken into account. Surface-mounted-resistive elements are incorporated midway connecting between the adjacent patches to reduce the amount of backscatter from the surface. The reflection coefficient of absorber with resistive elements of 440Ω where upon the incident electromagnetic energy should be absorbed is up to 34dB.

Timing estimation based on normalized 3rd-order central moment for symmetric correlator in OFDM systems

We proposed a new method for accurate timing estimation in OFDM systems. A conventional timing estimation based on autocorrelation and crosscorrelation experience performance degradation due to multipath channel distortion. The proposed method is developed based on normalized 3rd-order central moment for symmetric correlator. Based on these 3rd-order central moment, a binary hypothesis testing problem is formulated. Computer simulations show that the method is robust in fading multipath channels, achieving better performance than the existing methods in lower SNR.

Improved timing estimation based on symmetric correlator using statistical change of correlator for OFDM systems

An improved method for estimating the symbol timing offset based on symmetric correlator using statistical change of correlator in preamble-aided OFDM systems is presented. It uses a preamble structure that have symmetrical property and combines with statistical change of Correlator to achieve a near-ideal timing performance without degradation in multipath channel environment. Computer simulations show that the method is robust in fading multipath channels, achieving better performance than the existing methods.

An improved timing offset estimation based on symmetric identical training symbol for OFDM systems

An efficient algorithm based on symmetric identical training symbol has been proposed for timing offset estimation in OFDM system. The scheme is based on the transmission of a training symbol composed of two identical halves that have symmetrical property in time domain. In this paper we improve this algorithm by adding phase shift to the second halve of training symbol at the receiver side. This makes timing offset estimation not only robust against carrier frequency offset (CFO), but also the channel and noise effect. Simulation results show the proposed method can improve the performance of timing offset estimation based on symmetric identical training symbol.