Dadang Gunawan

The Interference on WCDMA System in 3G Coexistence Network

The coexistence network of different 3G technologies (WCDMA and cdma2000) requires analysis of its adjacent channel interference. In this paper, we investigated the interference on WCDMA system that caused by cdma2000 network. Several scenarios and calculation models were applied to measure impacts on uplink and downlink scheme. The results showed that interference from cdma2000 influence WCDMA performance significantly. Distance between coexistence terminals (MS and BS), their number, and guard band frequency determined minimum allowed received power at WCDMA BS and SIR in WCDMA MS, which lead to capacity degradation

Interference analysis of guard band and geographical separation between DVB-T and E-UTRA in Digital Dividend UHF band

Digital Dividend is the spectrum available from the release of very precious spectrum when full migration of analog terrestrial television transmission towards digital terrestrial television transmission has been fully undertaken. What makes Digital Dividend is extremely important is that the fact the spectrum located in lower UHF band below 1 GHz. Therefore, it is optimum in terms of the need of coverage and bandwidth. The main potential services in Digital Dividend are mobile broadband and digital terrestrial broadcasting. The objective of this study is to find out the minimum guard band and minimum distance between mobile broadband and digital terrestrial broadcasting. The interference analysis has been undertaken using SEAMCAT (Spectrum Engineering Advanced Monte-Carlo Analysis Tool) software. Several scenarios between DVB-T and E-UTRA, such as co-channel and adjacent-channel interferences, variation of distance between DVB-T and E-UTRA devices, and different directions of link have been studied. The results obtained provide some figure regarding the minimum guard-band required and minimum distance between DVB-T and E-UTRA systems.

PAPR reduction using Huffman coding combined with clipping and filtering for OFDM transmitter

Orthogonal Frequency Division Multiplexing (OFDM) technique has some drawbacks. One of them is high peak-to-average power ratio (PAPR). This paper proposes a technique to reduce the PAPR using Huffman coding combined with clipping and filtering (CF). The simulation results show that using the combination of Huffman and CF methods is more effective than using each method separately. By using 52 subcarriers and QPSK modulation, about 7 dB PAPR reduction is achieved.

The Effectiveness of Using Source Coding to Reduce PAPR in OFDM System

Large peak-to-average power ratio (PAPR) is one of drawbacks in orthogonal frequency division multiplexing (OFDM) system. Several methods have been proposed to reduce the PAPR. The use of source coding such as Huffman coding and run length encoding (RLE) offers significant PAPR reduction. It is found that the use of Huffman coding yields better reduction about 1 dB than RLE. In addition, by using Huffman coding yields out-of-band spectrum 0.5 dB lower than RLE.

Comparison of l1-Minimization and Iteratively Reweighted least Squares-l p-Minimization for Image Reconstruction from Compressive Sensing

Compressive sensing is the recent technique in data acquisition that allows to reconstruct signal form far fewer samples than conventional method i.e. Shannon-Nyquist theorem use. In this paper, we compare l1-minimization and Iteratively Reweighted least Squares (IRlS)-lp-minimization algorithm to reconstruct image from compressive measurement. Compressive measurement is done by using random Gaussian matrix to encode the image that the first be divided into number of blocks to reduce to the computational complexity. From the results, IRlS-lp and l1-minimization provided almost the same image reconstruction quality, but the IRlS-lp-minimization resulted the faster computation than l1-minimization algorithm.

Implementation of genetic zone routing protocol (GZRP) in 3G-WiFi Offload Multi Base Station

Offloading Technology Metropolitan Advanced Deliver Network (MADNET) which has been developed from several previous studies make the best solution to address the traffic density in a cellular operator. One of them is the implementation of third generation (3G), lately WiFi Offload is being developed, this is in line with the WiFi network in Urban and Metropolitan Networks. MANET is a technology which is the development of WiFi. On MANET routing concepts genetic zone routing prtocol (GZRP) are very useful in treating bottle neck in Multi Base Station WiFi network. In the present study, the concept will be combined with vertical hand off (VHO) Algortihm on 3G-WiFi Offload Network Multi Base Station. Based on the results of this simulation can improve troughput and reduce handover delay and end-to-end delay tolerance.

Uplink resource allocation algorithms with fractional power control as power constraints for OFDMA system

In this paper, two algorithms in resource allocation with fractional power control scheme are proposed and evaluated. In these algorithms, we joint chunk allocation and unequal power allocation in one chunk by considering fractional power control scheme as power constraint on each user to improve the sum of spectral efficiency of users and fairness among users. In order to evaluate our proposed algorithms, we compare the performances of our proposed algorithms with those of the previous algorithms with fractional power control scheme as power constraint in each user. From the simulation results are shown that our proposed algorithms can improve the sum of spectral efficiency and fairness among users in macrocell urban and suburban condition.

Enhanced Individualization of Head-Related Impulse Response Model in Horizontal Plane Based on Multiple Regression Analysis

One key issue in modeling head-related impulse responses (HRIRs) is how to individualize HRIRs model so that it is suitable for a listener. The objective of this research is to establish multiple regression models between minimum phase HRIRs and the anthropometric parameters in order to individualize a given listener’s HRIRs with his or her own anthropometric parameters. We modeled the entire minimum phase HRIRs in horizontal plane of 37 subjects using principal components analysis (PCA). The individual minimum phase HRIRs can be estimated adequately by a linear combination of ten orthonormal basis functions. We proposed an enhanced individualization method based on multiple regression analysis of weights of basis functions by utilizing eight anthropometric parameters. Our objective simulation’s results show that the estimated minimum phase HRIRs have small error and can be perceived similarly as the measured ones. In addition, the subjective localization performance of the estimated HRIRs is improved compared to the measured HRIRs.

Modification of dummy sub-carriers method to reduce PAPR in OFDM system

Orthogonal Frequency Division Multiplexing (OFDM) has been employed in many wireless standards. However, one of the drawbacks of OFDM is high peak-to-average power ratio (PAPR). We propose modification of dummy sub-carriers to reduce the PAPR. We use random dummy signal and multiplication factor to yield better PAPR. The PAPR reduction of about 4 dB at probability of 10−2 is achieved by using 2 dummy sub-carriers.

RCPC-Encoded V-BLAST MIMO with MMSE-Based Detection

A Rate-Compatible Punctured Convolutional (RCPC)-encoded Vertical Bell Laboratories Layered Space-Time (V-BLAST) MIMO system to provide a robust wireless communication link is proposed. The V-BLAST detection is based on Minimum Mean-Squared Error (MMSE) criterion, to alleviate the noise enhancement commonly found in the original V-BLAST scheme based on Zero Forcing criterion. Different code rates and transmit powers are allocated to data streams emitted from the multiple transmit antennas, according to the attenuation levels of the subchannels. This scheme is efficient in terms of transmit power and bandwidth usage, as the data stream entering a destructive subchannel is given low transmit power and high code rate. Simulations show that the proposed system can attain good performance at a reasonably low Eb/No.