|
Bandwidth Enhancement of Cellular Broadband Communication
-- Pankaj Shankar Srivastava and M R Meshram
Bandwidth required to transmit a signal or bandwidth of a transmission media plays an important role in any form of communication (wired or wireless). This paper explains the importance of bandwidth and how we can choose modulation technique, multiple access technique and other parameters for broadband communication so that the available bandwidth gets enhanced. The paper compares the majorly used analog to digital encoding technique Delta Modulation (DM) with Pulse Code Modulation (PCM) in terms of required bandwidth for number of users (channels). It was found that DM is better. The probability of error is an important parameter to fix channel capacity. In the analysis, it was found that probability of error for Binary Phase Shift Keying (BPSK) and Orthogonal Frequency-Division Multiplexing (OFDM) is better than Quadrature Phase Shift Keying (QPSK) and Direct Sequence (DS)-Code Division Multiple Access (CDMA) respectively. We can efficiently utilize bandwidth by selecting bandwidth-efficient analog to digital encoding methods like DM and BPSK as modulation techniques, and OFDM-CDMA as multiple access technique with digital equipments.
© 2012 IUP. All Rights Reserved.
Wideband Circularly Polarized Rectangular Microstrip Array Antenna
-- S L Mallikarjun, P M Hadalgi, S A Malipatil and P V Hunagund
This paper presents a 10-element Rectangular Microstrip Array Antenna (10-RMSAA) fed through a modified corporate feed network. The measured experimental results show that the bandwidth of 10-RMSAA is improved to 31.39% covering 9.14-12.54 GHz frequency range with circular polarization (CP) operation. The proposed antenna shows an improvement in gain with broadside radiation pattern. This microstrip array antenna can be used for X-band short-range microwave applications and satellite applications.
© 2012 IUP. All Rights Reserved.
Performance Analysis of Cooperative MIMO Techniques
in Wireless Sensor Networks
--Vibhav Kumar Sachan and Syed A Imam
The issue of energy saving is significant since in a battery-operated wireless node, the battery energy is finite and a node can only transmit a finite number of bits. To extend the life span of a node in wireless sensor networks, an energy-efficient communication technique is mandatory so that energy expenditure is minimized, and at the same time, it satisfies the given throughput and delay necessities. In this context, we analyze the performance of cooperative Multiple-Input Multiple-Output (MIMO)-based communication in wireless sensor networks. In this paper, we analyze the communication method to reduce the total delay and total energy expenditure required to send specified quantity of bits. This energy efficiency investigation of MIMO scheme is broadened to individual single antenna nodes that collaborate to form multiple antenna transmitters or receivers. It is also seen that over some distance ranges, cooperative MIMO broadcast and reception can simultaneously achieve both energy savings and delay reduction. Simulations show that with proper design, cooperative MIMO-based communication is more faster and energy-efficient as compared to non-cooperative approach e.g., Single-Input Single-Output (SISO) for larger distances and prolong sensor network lifetime.
© 2012 IUP. All Rights Reserved.
Reversible Watermarking Using Double Reversible
Contrast Mapping Method
-- Rajendra D Kanphade and Navnath S Narawade
Reversible watermarking is very popular in medical and military applications. Reversible Contrast Mapping (RCM) can achieve 100% original image as well as watermark. This method is simple equation that can be applied to pairs of pixels. Here we have compared Coltuc and Chassery RCM equation with its double RCM equation. We found that though double RCM equation is suitable for reversible watermarking, its embedding capacity and quality decrease. But for some pairs of pixels (with which normal RCM does not work), double RCM is completely invertible. The double RCM equation is not suitable against attacks. The data space occupied by Least Significant Bits (LSBs) is suitable for data hiding. But our proposed double RCM method is suitable for all images.
© 2012 IUP. All Rights Reserved.
A Comparative Study of UTF-8, UTF-16, and UTF-32
of Unicode Code Point
--Sanjeev Kumar
Unicode is a critical enabling technology for developers who want to internationalize applications for global environments. Unicode assigns a unique number for every character, irrespective of what the platform, or the program, or the language is. The Unicode Standard has been adopted in the industry by Apple, HP, IBM, Microsoft, Oracle, SAP, Sun, Sybase, and many others. Unicode is required by modern standards such as XML, Java and WML, and is the official way to implement ISO/IEC 10646. It is supported in many operating systems, all modern browsers, and many other products. The emergence of the Unicode standard, and the availability of tools supporting it, is among the most significant recent global software technology advances. Each available format of UTF-8, UTF-16 and UTF-32 has its own pros and cons. The comparison of the following three formats is discussed in this paper.
© 2012 IUP. All Rights Reserved.
|
