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Aarthi, V.
- Performance Enhancement of Modified SOVA Decoding Algorithm for Turbo Codes
Authors
1 Bannari Amman Institute of Technology, Sathyamangalam, TamilNadu, IN
2 Bannari Amman Institute of Technology, Sathyamangalam, TamilNadu, IN
Source
Networking and Communication Engineering, Vol 3, No 4 (2011), Pagination: 229-234Abstract
Turbo coding (TC) has been adopted as a channel coding scheme for several 3G mobile systems, in particular GPP(third Generation Partnership Project) and 4G standards for high data rates. Turbo decoder uses any one of the decoding algorithms, Maximum A posteriori Probability (MAP), or Soft Output Viterbi Algorithm (SOVA) because it produces error correction near to Shannon’s limit. SOVA is an extension of classical Viterbi algorithm which is incorporated with a-priori information. The performance of SOVA algorithm is improved by scaling the extrinsic information exchanged between two decoders. Modified SOVA (MSOVA) algorithm is achieved by fixing an arbitrary value for inner decoder (S2) and an optimized value for the outer decoder (S1). A simple but effective technique to enhance the performance of MSOVA, called Enhanced SOVA (ESOVA) is proposed. In ESOVA, the arbitrary scaling factor S2 is optimized and is made to adapt with received Eb/N0. The use of an emphatically determined optimal scaling factor improved the performance of the decoding algorithm in terms of Bit Error Rate (BER). A comprehensive analysis of the proposed algorithm, by considering different channel conditions and code rates are presented. Appropriate mathematical relationship between scaling factor and Eb/N0 is also proposed.
Keywords
Extrinsic Information, Scaling Factor, SOVA, Turbo Codes.- Simulation and Implementation of AC-DC Interleaved Boost Converter with Voltage Multiplier for PHEV
Authors
1 Department of Electrical and Electronics Engineering, SSN College of Engineering, Chennai, IN
Source
ICTACT Journal on Microelectronics, Vol 2, No 2 (2016), Pagination: 247-253Abstract
A Plug in hybrid electric vehicle (PHEV) is a hybrid vehicle which employs battery to power up the vehicle motor and it has higher efficiency and low cost compared to the conventional internal combustion engine based vehicle. In PHEV, the charging and discharging of battery is accomplished using a power electronic converter system. This paper focuses on the implementation of an AC-DC interleaved boost converter with voltage multiplier cells for charging of Plug-in Hybrid Electric Vehicle (PHEV). The IBC topology with switched capacitor and coupled inductor is chosen for this work. The proposed AC-DC converter is employed to reduce the ripples at the input and output along with multiplier block to reduce the narrow turn off periods. The output of IBC is fed to a bidirectional DC-DC converter for charging the battery in PHEV. Simulation of the proposed converter is studied in MATLAB. The performance parameters of the converter are computed. Simulation results are verified practically.Keywords
IBC, Voltage Multiplier, Bidirectional Converter, Ripple.- An Approach to Detect Sybil Attack in VANET by Neighbor Processing Algorithm
Authors
1 Department of Computer Applications, S. A. Engineering College, IN
Source
Wireless Communication, Vol 11, No 4 (2019), Pagination: 70-73Abstract
In the recent years, researchers are focusing on the Vehicular Adhoc Network (VANET) field due to the lifesaving factor. VANET is one of the important application in the Mobile Adhoc Network (MANET).VANETs are defined as the set of the vehicles or the Road Side Unit(RSU) that communicate through the Wireless Local Area Network (WLAN) .VANET is an application of Intelligent Transportation System (ITS) that aims towards the safety and comfort of drivers and passengers . It is a network where vehicles communicate with each other to find the distance and finding the obstacles in the road. As it is a open network everyone can use it, so security and privacy is the major issue in the VANET. Especially in the authentication process, the vehicles needed to be authenticated before accessing or sending messages to the network. There are many attacks in the VANET application one of the major attack is the Sybil attack. Sybil attack is that attacker is creating multiple identities or making an illusion of the traffic congestion by the malicious nodes .This paper presents about the VANET overview, Sybil attack detection and proposes an approach neighborhood algorithm that is used to find the malicious nodes in Sybil attack.
Keywords
Vehicular Adhoc Networks, VANET Security, Sybil Attack, Timestamp Series.References
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