Volume 5, Issue 1, October 2010

Characteristics of FH Pattern Likelihood Ratio Decision Method against CW Jamming or/and Burst Noise [Full Text]

Shin’ichi Tachikawa Nagaoka,  National College of Technology, Nagaoka,Niigata, 940-2188, Japan
Kenji Kobayashi Nagaoka, National College of Technology, Nagaoka, Niigata, 940-2188, Japan

This paper proposes an improved method of a lump likelihood ratio calculation in detection of frequency hopping (FH) pattern of multilevel FSK (MFSK). In a conventional lump likelihood ratio calculation, it is calculated by employing probability density function of AWGN and signal gain of each frequency slot. In this paper, a new calculation method employing a probability density function including CW jamming or/and burst noise is proposed. Theoretical analysis of the lump likelihood ratio and estimation methods of CW jamming and burst noise are derived. Then, by computer simulations, it is shown that BER of the proposed method is superior to that of the conventional method for several conditions.


Analysis of Selected Mapping and Partial Transmit Sequence for PAPR Reduction
[Full Text]

Anil Singh Rathore, Departement of Electronics and Communication Engineering, BBDNITM, G.B. Technical University, Lucknow, India
Dr. Neelam Srivastava, Departement of Electronics Engineering, IET, G.B. Technical University, Lucknow, India

Abstract: - Two powerful and distortion less peak power reduction schemes for Orthogonal Frequency Division Multi-plexing (OFDM) are compared. One investigated technique is selected mapping (SLM) where the actual transmit signal is selected from a set of signals and the second scheme utilizes phase rotated partial transmit Sequences (PTS) to construct the transmit signal. Both approaches are very flexible as they do not impose any restriction on the modulation applied in the subcarriers or on their number. They both introduce some additional system complexity but nearly vanishing redundancy to achieve markedly improved statistics of the multicarrier transmit signal. The schemes are compared by simulation results with respect to the required system complexity and transmit signal redundancy.


Effects of Imperfect Power Control and Sectorization on the Capacity of Multiclass CDMA System with Beamforming
[Full Text]

Gunawan Wibisono, Department of Electrical Engineering, Faculty of Engineering University of Indonesia, Kampus Baru UI Depok 16424, Indonesia
Lina Oktaviana Sari, Department of Electrical Engineering. JakartaState Politechnic, Kampus PNJ Depok 16424, Indonesia

Abstract—Communications systems based on code division multiple access (CDMA) are growing fast this day. To support third generation technology (3G), CDMA has been expected to fulfill requirements of audio, data, and video services with higher system capacity. Audio, data and video services in CDMA systems can be viewed as multiclass CDMA system. In practice, the capacity of CDMA is limited by interferences, so that any reduction of the interference will directly cause capacity increases. Methods, such as sectorization and power control could reduce the interference. In this research, the impact of imperfect power control and imperfect sectorization to reverse-link user capacity of CDMA system based on signal to interference ratio ( SIR ) by using beamforming at mobile station (MS) transmitter and base station (BS) receiver will be analysed. It is shown from the results that the capacity of multiclass CDMA system decreases caused by the imperfect power control and imperfect sectorization. The system with sectorization using beamforming has large capacity of multiclass system than the system using beamforming without sectorization. The total addition of antenna beamforming elements at BS receiver and MS transmitter not always has large capacity of multiclass system, however depend on distribution of antenna beamforming elements at BS receiver and MS transmitter. The system with sectorization using beamforming has large capacity of multiclass system than the system with sectorization without beamforming. Optimum capacity of multiclass system achieved, when beamforming has even number of receive antenna elements Kr.


Modal analysis and dispersion curve of unconventional Bragg waveguide
[Full Text]

Y.K.Prajapati, Bundelkhand Institute of Engineerng and Technology, Jhansi, India
Vivek Singh, Department of Physics, Banaras University, Varanasi, India
J.P. Saini, Bundelkhand Institute of Engineerng and Technology, Jhansi, India

Abstract— In a previous paper we develop a transfer matrix theory that applies to any unconventional symmetric fiber surrounded by Bragg cladding. Using this formalism, along with Galerkin method, we study the waveguide dispersion for the m = 0 mode in an air-core super elliptical Bragg fiber and showed it is agrees well with the transfer matrix method. Computed results are shown in the form of dispersion curves and are compared with standard step index fiber. The Galerkin method is conceptually simple and requires only an eigenvalue solver without the need of special functions.


Prediction of Vehicle Classification And Channel Modelling For Intelligent Transportation
[Full Text]

Nirmalendu Bikas Sinha, College of Engineering & Management, Kolaghat, K.T.P.P Township, Purba-Medinipur, W.B, 721171, India
D.Mondal, Future Institute of Engineering & Management, Sonarpur, W.B, India
M.Mitra, Bengal Engineering and Science University, Shibpur, Howrah, W.B, India
R.Bera, Sikkim Manipal University, Majitar, Rangpo, East-Sikkim, India.

A new test method of sufficient flexibility is developed to describe most pulse Doppler radar search systems which can be used to predict the classification of the target. The object of this section is to predict the detection capability of a pulse Doppler radar where the Doppler filter bandwidth is much wider than the  bandwidth of each spectral line in the received signal. This method can easily classify various targets. Finally authors developed new channel modelling technique for the best utilization in intelligent transportation.


Traffic Analysis of Wireless IP Networks [Full Text]

Mohammad Shahidul Islam
, Electronic and Telecommunication Department, Faculty of Science and Information Technology, Daffodil International University, Sukrabad, Dhaka, Bangladesh.

Wireless networks have crossed almost five billion subscribers worldwide with first, second and third generation mobile networks. The main service was voice and more recently modem-based low-rate and high rate data services. Because of the voice oriented traffic and circuit-switching technology, these networks are dimensioned and designed using the traditional traffic theory in telecommunications. Their design is based on high-cost centralized switching and signaling equipment and base stations as wireless access points. Another technology dominated the world in the wired communication networks is IP technology. The transparency of the Internet Protocol (IP) to all traffic types and low-cost switching equipment made it very attractive to operators and customers. The 3G of mobile networks introduces wide spectrum and high data rates as well as different types of circuit-switched and packet-based services. It provides IP connectivity besides the circuit switching. Future generation mobile systems are expected to include heterogeneous access technologies, such as wireless LAN and 3G, as well as end-to-end IP connectivity. The different type of traffic services and access technologies creates new possibilities for both operators and users. On the other hand, it raises new traffic and design issues. This paper provides traffic analysis and quality of service (QoS) of wireless IP networks with multiple traffic classes.