Wireless Communication

Amit V. Patel ¹, Yogeshwar P. Kosta ², Neetirajsinh Chhasatia ³

Affiliations
1 C S Patel Institute of Technology, Changa, IN
2 Charotar University of Science and Technology, Changa, IN
3 Electronics & Communication Engineering Department, Charotar University of Science and Technology-CHARUSAT, Changa, IN

Abstract

Waveguides are robust structure and handle high power well, compared to transmission line filter such as coplanar lines, microstrips and striplines. Modeling techniques of the waveguide of the filter using the non-planner model that is most preferable among all present for low cost mass production of microwave and millimeter wave circuits and systems. The mathematical computations for the design dimensions of a wave guide band pass filter are implemented using HFSS software based on the insertion loss method. This paper basically concerned with the improvement characteristics of post coupled designs that have been modeled. This paper demonstrates the approach to overcome the limitation inherent in post coupled , hairpin as well as suppression of the harmonic which is prominent in the micro strip coupled filter and resonator topology. This has been achieved using the design concept of finite conductive post coupled obstacles into the perfect impedance match rectangular waveguide. The modified topologies of the post coupled along with the concept of reduced insertion loss and better return loss with improved quality factor has been achieved. Furthermore, presented structures results are sensitive to standard design equations and dimensions of the elements used. The resonator topologies were designed here at the center frequency of 11.2 GHz, with insertion loss -0.04dB and return loss -67.8616dB with narrow bandwidth and VSWR (Voltage standing wave ratio) =1. 05.

Keywords

T-Post, Insertion Loss, Return Loss, Improved Characteristics.

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Ninad S. Bhatt ¹, Yogeshwar P. Kosta ²

Affiliations
1 Veer Narmad South Gujarat University, Surat, Gujarat-395007, IN
2 Marwadi Education Foundation, Rajkot, Gujarat-360001, IN

Abstract

In today’s wireless communication system, one of the major challenges is to maintain good quality of recovered speech at receiver with unpredictable variations and behavior in channel conditions. Modeling of channel is always a difficult task and channel condition is a decisive factor for quality of speech being reproduced at receiver. Till date many techniques have been evolved to mitigate the effect of channel. GSM Adaptive Multi Rate (AMR) 06.90 is one of such technique which counteracts the deleterious effect of channel on speech signals. This technique employs variable bit rate that dynamically switches to specific modes of operation (switching bit rates – called modes of operation) depending upon the channel conditions.

This paper yields development of AMR coder based on Code Excited Linear Prediction algorithm. By affecting some of the key parameters of CELP coder, variable bitrates of AMR coder can be achieved tuning to different channel conditions. An e-test bench using Simulink is created in order to implement AMR coder based on CELP algorithm, and the same studied and investigated through series of simulations. Subsequently Subjective (Mean Opinion Score) and Objective (Perceptual Evaluation of Speech Quality, Signal to Noise Ratio, Segmented SNR) analysis have been carried out on proposed algorithm to evaluate its performance for various bitrate modes. The obtained results clearly advocate significant improvement (for each Subjective and Objective analysis parameters) over [17] while implemented in Simulink. It also reveals the fact that speech quality improvement is evident with respect to increase in bitrate modes. In next phase real time implementation of proposed coder on TMS320C6713 DSP Kit using Simulink Real Time Workshop (RTW) and Code Composer Studio has been discussed. The goal of real time implementation of the proposed coder is to observe the feasibility of coding and decoding of the proposed coder on DSP TMS320C6713 kit.

Keywords

CELP, Code Composer Studio, ETSI, GSM-AMR, Simulink, Speech Coding.

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Hemal Shah ¹, Yogeshwar P. Kosta ², Nisha Patel ¹

Affiliations
1 Ganpat University, Gujarat, IN
2 Marwadi Education Foundation, Rajkot, IN

Abstract

In this paper is a precipitate of various applications/projects concerning delay tolerant networks. Our study summarizes each of the applications independently, aspects consisting of purpose, network type, environment, and network setup and data collection methodology. This study is primarily done to discover common parameters that will help in generalization, pin down niches which need to be addressed in the context to attempt unification amongst different project application and also propose best technique for specialized application. Further, this paper will serve as quick reference base to summarize the details.

Keywords

Adhoc Network, DTN, Routing, Wireless Networks.

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Hemal Shah ¹, Yogeshwar P. Kosta ²

Affiliations
1 Ganpat University, Gujarat, IN
2 Marwadi Education Foundation, Rajkot, IN

Abstract

A communications network that withstands long delays or outages and is capable of storing packets temporarily stationed in intermediate nodes, until an end-to-end route is re-established or regenerated is known as a delay tolerant network or in short DTN. This paper aims to consolidate general & basic aspects relating to information needs to efficiently execute DTN routing. We start by presenting the evolution of some routing protocols, spotting few routing schemes relevant to us, discuss their groups and classifications, their operating network environment, and through critical study and observation, to identify specific parameters that are common across relevant schemes associated with routing that helps to bring out the advantage and disadvantage associated with them in an attempt to establishing some possible future extensions-of-the-existing through consolidation - accomplished by capturing, organizing and showcasing the same in metrics and proposing new schemes as well. This leads us to identify specific schemes and techniques that will help us to exploit the delay and utilize the time judiciously to improve the over all efficiency of information exchange in a DTN network. The essence of this study being; to utilize efficiently the temporal period (delay) by opportunistically establishing connectivity - in a strategic manner, to help exchange information across by locally distributed resources, thus making optimal use of available network resources and enhancing the efficiency of information exchange.

Keywords

Forwarding, Replication, Single-Copy, Multiple-Copy, Relay, Delivery Ratio, Delay, Throughput, Local Resource, Routing Techniques, Routing Efficiencies, Protocol Introduction.

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