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Optimization of Channel Capacity
of Multi-Rate Multi-Code CDMA
for Broadband Packet Wireless Access
-- Pankaj Shankar Srivastava and M R Meshram
This paper presents a mathematical technique for determining the optimum packet size in multi-rate multi-code
Code Division Multiple Access (CDMA) network. This scheme optimizes the channel capacity and tries to meet the
multi-rate transmission demands of all the users by varying the size of packets. Throughput is defined as the expected value of
the total number of successful transmitted packets/slot. The Analysis shows that as we increase the size of packets
keeping processing gain, error detection and correction capability
(t) of the network fixed, throughput drops with increase
in the number of transmitted packets/slot. It is found that channel capacity for packet length L = 64, 128, 256, 512 and 1,024 in terms of throughput are 120, 72, 50, 38, 30 for t = 10, respectively, and are 420, 140, 79, 50 and 38 for t = 20, respectively. It is concluded that to optimize the channel capacity, we have to transmit possible large size
packets as per the flow control of the network.
© 2011 IUP. All Rights Reserved.
Matlab Modeling and Simulation
of a WiMAX System
-- V K Chaubey and Rakesh Kumar Jain
This paper addresses physical layer modeling of all the necessary features of 802.16 (d) Worldwide Interoperability
for Microwave Access (WiMAX) system. WiMAX system model code has been developed in Matlab to simulate
and analyze the performance of a system. Bit Error Rate (BER) performance of the system is analyzed over Additive
White Gaussian Noise (AWGN) channel and Rayleigh faded multipath channel. Rayleigh faded channel is modeled
using Jakes' sum-of-sinusoids method and Pilot-based channel estimation is employed. Recursive Systematic
Convolution (RSC) turbo code is included in the modeling to improve the BER performance.
© 2011 IUP. All Rights Reserved.
Optimized Technique for Speech Noise Elimination Using Traditional Spectrum Subtraction
-- Kinnar G Vaghela and Z M Patel
The spectrum subtraction is the classical algorithm and the most common technology to eliminate the noise from
the speech, which is dealing with broadband noise. It subtracts the Noisy Speech from the noise spectrum estimation,
and generates the enhanced speech signal. The traditional spectrum subtraction suppresses this noise and improves
the signal to noise ratio. Based on MATLAB, the spectrum subtraction algorithm was implemented, and results of
traditional spectrum subtraction were compared with different noise conditions. Simulation shows that the improved form
of spectrum subtraction can effectively reduce the background noise and improve signal to noise ratio..
© 2011 IUP. All Rights Reserved.
Role of Pulse Shaping in Modern Wireless Communication
-- A S Kang and Vishal Sharma
The application of signal processing techniques to wireless communications is an emerging area that has
recently achieved dramatic improvement in results and The First Generation (1G) and Second Generation (2G) of mobile
telephony were indented for voice transmission. The Third Generation (3G) is meant for both voice and data applications. The
thirst for effective communication and higher bandwidth has led to the evolution of the next generation wireless systems,
and newer technologies are being deployed to provide the user with information and entertainment anywhere and
anytime. The 3G mobile radio systems (International Mobile Telecommunication (IMT)-2000 globally and Universal
Mobile Telecommunication System (UMTS) in Europe) are becoming a reality today. The network infrastructure is currently
being deployed in many countries. Manufacturers, network operators and service providers are now focusing on the
development of new services and applications as well as suitable business models to make 3G mobile communication an
economic success. One important lesson to be learnt from the development of 3G is that the potential future services and
applications, including the expected user behavior should be taken into account from the very beginning to derive the
technical requirements. This approach is essential to enable the economic success of future system. The present paper deals
with overview of pulse shaping in modern wireless communication in the Wideband Code Division Multiple Access
(WCDMA) domain.
© 2011 IUP. All Rights Reserved.
The Challenges of Handset Antenna Design and Computer Aided Design, Development
and Fabrication
of Circular Microstrip Antenna
-- R D Kanphade, D G Wakade and N T Markad
Design and realization of microstrip antennas in S-band at 2.4 GHz is reported in this research paper. It is shown
that the design adopted for circular microstrip antenna is quite accurate. By using the conventional MIC
fabrication technology compact light weight microstrip antenna can be realized. The desired narrow band achieved the
circular microstrip antenna. Antennas are designed and fabricated on the substrate of dielectric constant 4.22 and thickness
of 1.6 mm. Simulation is done using the microwave software to achieve the desired results. The purpose of this paper
is to introduce the reader to the challenges of designing an antenna integrated into modern handset. It provides
the reader with insight into all the details associated with handset antenna design and the type of measurements used
to characterize handset antennas.
© 2011 IUP. All Rights Reserved.
Compact Dual-Band Single Feed Rectangular Microstrip Antenna
-- P A Ambresh, P M Hadalgi and P V Hunagund
A novel compact dual-band single feed rectangular microstrip antenna is designed and presented to suit
applications in wireless communication systems for 3-4 GHz frequency region. The behavior of various antenna parameters
is studied. With various slots on patch and air filled dielectric medium, 16% compactness with dual-band operation
is achieved. Impedance bandwidth of 250 MHz (6.76%), gain of 6.31 dB and 4.88 dB with broadside radiation
pattern are also achieved. The 3 dB half power beam widths of patch antenna are
43o and 92o respectively. Proposed
antenna suits for wireless application such as WiMAX, radar communication, WLAN and UK-based fixed satellite services
(3-4 GHz).
© 2011 IUP. All Rights Reserved.
A Novel Design of Dual-Band,
High-Gain Square Microstrip Antenna
-- Kishan Singh and S N Mulgi
A novel design of square-ring slot loaded square Microstrip Antenna (MSA ) is presented for dual band and high
gain operation. The magnitude of lower and upper operating band is found to be 6.42% and 38.74% respectively. The
upper operating band is enhanced to 62% by incorporating square-ring slot in the ground plane. If a parasitic strip is
used around the patch, the antenna enhances the lower operating band to 8.76% and upper operating band to
64.60% without changing the nature of radiation characteristics. This technique also enhances the gain to 12.85 dB.
The design concepts of antennas are presented and experimental results are discussed.
© 2011 IUP. All Rights Reserved.
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