i-manager's Journal on Communication Engineering and Systems (JCS)


Volume 4 Issue 4 August - October 2015

Research Paper

Comparison of Hybrid Diversity Systems Over Rayleigh Fading Channel

Hima Pradeep V* , Seema Padmarajan**
* PG Scholar, Department of Electronics and Communication Engineering, Sree Narayana Gurukulam College of Engineering, Kerala, India.
** Assistant Professor, Department of Electronics and Communication Engineering, Sree Narayana Gurukulam College of Engineering,
Pradeep, H. V., and Padmarajan, S. (2015). Comparison of Hybrid Diversity Systems Over Rayleigh Fading Channel. i-manager’s Journal on Communication Engineering and Systems, 4(4), 1-6. https://doi.org/10.26634/jcs.4.4.3710

Abstract

In wireless communication, robustness against fading is the most important issue for reliable communication. Diversity technique is a well-known scheme to remove the adverse effect of fading in wireless channels. Transmitted signal is received through multiple numbers of independent fading paths in diversity receiver. These signals are combined to improve the Signal-To-Noise Ratio (SNR) of the received signal. There are several methods to combine these multipath components including Maximal Ratio Combining (MRC), Equal Gain Combining (EGC) and Selective Combining (SC). By considering various aspects like low power consumption and higher diversity gain, hybrid combining techniques have been receiving great interest in recent days. The performance of newly designed hybrid diversity scheme, MRC/EGC for Rayleigh Fading channel in which M number branches are Maximal Ratio Combined and L number of branches are Equal Gain Combined is evaluated in this paper by comparing the existing hybrid MRC/SC system by analyzing the performance of the system in terms of Outage Probability and Average Bit Error Rate (ABER) for coherent and noncoherent modulation schemes.

Research Paper

Execution of Adaptive STFT Calculation for LFM and QPSK Signals

Ramya Teja N* , Srinivas Bachu**, Sri Harsha Davuluri***
*_*** Assistant Professor, Department of Electronics and Communication Engineering, Guru Nanak Institutions Technical Campus, Hyderabad, Telangana, India.
Teja, R. N., Bachu, S., and Davuluri, S. H. (2015). Execution of Adaptive STFT Calculation for LFM and QPSK Signals. i-manager’s Journal on Communication Engineering and Systems, 4(4), 7-13. https://doi.org/10.26634/jcs.4.4.3711

Abstract

Regularly, time-frequency investigation is finished by sliding a window through the time area information and figuring the fourier transform of the information inside of the window. The decision of the window length figures out if specular or resounding data will be stressed. A slender window will confine specular reflections yet will not be sufficiently wide to oblige the gradually changing worldwide resonances. A wide window cannot transiently isolate reverberation and specular data, so we will adjust window length as per changes in frequencies. For this situation, we understand the determinations of LFM and Quadrature Phase Shift Keying (QPSK) signals. The quantitative performance of the proposed method is analyzed using average amplitude, output frequency and phase. The results prove that, the design of proposed method is very simple. So by using adaptive STFT, we can improvise the existing warfare and simplify the existing complex RADAR techniques.

Review Paper

A Review on Different Resonator Based Microwave Filters

Priyanka Srivastava* , Arvind Kumar Pandey**, R. K. Chauhan***
* PG Scholar, Communication Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur, India.
** Research Scholar, Madan Mohan Malaviya University of Technology, Gorakhpur, India.
*** Professor, Department of Electronics and Communication Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur, India.
Srivastava, P., Pandey, A. K., and Chauhan, R. K. (2015). A Review on Different Resonator Based Microwave Filters. i-manager’s Journal on Communication Engineering and Systems, 4(4), 14-22. https://doi.org/10.26634/jcs.4.4.3712

Abstract

High performance microwave filters have become the need of the modern wireless communication systems. This demands the designing of more compact and efficient microwave filters providing multiple bands. For the miniaturization and integration of the microwave filters, microstrip filters based on multiple mode resonators are of great significance. This paper reviews several multiple band-pass filters based on different multi-mode resonators by focusing on Stepped Impedance Resonator (SIR), Stub Loaded Resonator (SLR) and Ring/Loop Resonator (open and closed) based microwave filters. SIR has size reduction ability and harmonic control with wide tuning range. A SLR has a good stopband rejection ability. It can generate two modes that can efficiently reduce the size of the filters. Loop resonator can be used to reduce the size along with optimized characteristics of filters.

Review Paper

Ultra-Wideband Microstrip Antenna and Design - A Review

Jainendra Nath Tiwari* , G.S. Tripathi**
* Post Graduate, Department of Electronics and Communication, M.M.M. Engineering College, Gorakhpur, India.
** Associate Professor, Department of Electronics and Communication, M.M.M. Engineering College, Gorakhpur, India.
Tiwari, J. N., and Tripathi, G. S. (2015). Ultra-Wideband Microstrip Antenna and Design - A Review. i-manager’s Journal on Communication Engineering and Systems, 4(4), 23-27. https://doi.org/10.26634/jcs.4.4.3713

Abstract

This paper accomplishes the objective to understand the significance of UWB antenna. Utilization of UWB antenna is increasing day-by-day, thereby development is also necessary. To overcome its bulkiness, patch antenna can be a better alternative to make antenna smaller for UWB applications. This paper is a review of types of UWB antenna, methods to increase bandwidth, miniaturization and analysing the relationship between bandwidth and feeding methods. Microstrip antenna has a disadvantage of narrow bandwidth whereas UWB antenna has frequency band of 3.1-10.6 GHz. Antenna bandwidth can be increased by using different technique such as embedding slot, parasitic stub, bandstop transmission line, and hybrid techniques. Along with this, some techniques are used to overcome the problem of some narrowband application such as WLAN. The performance of the antenna is related with its parameters. Hence, by changing the parameters of antenna, different performance can be achieved.

Review Paper

Micro Ring Resonator Based Optical Filters for WDM Applications - A Review

Rahul Parganiha* , Sharad Mohan Shrivastava**, Pooja Sharma***, Prachi Agrawal****, Anuja Mishra*****
*,***-***** PG Scholar, Department of Communication Engineering, Chhattisgarh Swami Vivekanand Technical University, Bhilai CG, India.
** Assistant Professor, Department of Electronics & Telecommunication, Shri Shankarachrya Technical Campus, Bhilai CG, India.
Parganiha, R., Shrivastava, S. M., Sharma, P., Agrawal, P., and Mishra, A. (2015). Comparison of Hybrid Diversity Systems Over Rayleigh Fading Channel. i-manager’s Journal on Communication Engineering and Systems, 4(4), 28-38. https://doi.org/10.26634/jcs.4.4.3714

Abstract

In the recent years, optical networks has been proved out to be very efficient and faster compared to traditional satellite and wired network. Optical filters are needed for dynamic allocation and bandwidth selectivity of input signals in these networks. For filtering, micro ring Resonators are considered best due to their various advantages such as small size, light weight, effective operational capability and inexpensiveness. Integrated ring resonators are compact, integrated micro structures which can be used for Multiplexing/Demultiplexing, Modulation/ Demodulation, Switching and filtering of optical signals. This paper gives an overview of applications of Ring Resonators in modern optical communication system especially with Micro Electro Mechanical Systems (MEMS). We have focused this study in the field of optical filters. Structure and characteristics along with recent inventions and works done in this field has been summarized. The objectives for this survey paper are, 1) to explain basic structure, working principle, parameters and coupling configurations of optical ring resonator, 2) to discuss recent work done in the field of MEMS actuated optical filters and their characteristics and 3) to explore future scope for optical filters in communications.