Informatics Publishing Limited

P. Harish ¹, M. Palanivelan ², Sheila Anand ³

Affiliations
1 Department of Communication Systems, Rajalakshmi Engineering College, Chennai, IN
2 Department of ECE, Rajalakshmi Engineering College, Chennai, IN
3 Rajalakshmi Engineering College, Chennai, IN

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is one of the attractive technology for wireless communications with Multi-Carrier Modulation (MCM) technique offers a considerable multipath delay spread tolerance, high spectral efficiency, immunity to the frequency selective fading channels and power efficiency. High Peak-to-Average Power Ratio (PAPR) of the transmit signal is a major drawback of multicarrier transmission such as OFDM. Partial Transmit Sequence (PTS) is one of the commonly used schemes to reduce the PAPR. Conventional Partial Transmit Sequence (C-PTS) requires an exhaustive searching over all combinations of the given phase factors, which results in exponential increase to the computational complexity with the number of sub blocks. In this paper, we aim to obtain the desirable PAPR reduction with the low computational and phase search complexity. PTS based phase weighting techniques with low computational complexity, named Segmented Phase Weighting (SPW) and Iterative Phase Weighting (IPW), are proposed. On applying one of the linear transformation techniques called circular time shift to the candidate sequences obtained by SPW and IPW method, high PAPR reduction can be obtained. This system will slightly increase the computational complexity but greater reduction in PAPR. At the receiver, by utilizing the natural diversity of phase constellation for different candidates, the detector can successfully recover the original signal without Side Information (SI). PAPR reduction performance of both proposed schemes are analyzed, the simulation results show that the proposed Circular Time Shifted- Segmented Phase Weighting (CTS-SPW) and Circular Time Shifted- Iterative Phase Weighting (CTS-IPW) schemes achieve better PAPR reduction compared to the C-PTS scheme.

Keywords

Iterative Phase Weighting (IPW), Orthogonal Frequency Division Multiplexing (OFDM), Peak-to-Average Power Ratio (PAPR), Segmented Phase Weighting (SPW).

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M. Lakshmanan ¹, V. Noor Mohammed ², M. Palanivelan ², Shinde Ajay ¹

Affiliations
1 School of Electronics Engineering, VIT University, Vellore - 632014, Tamil Nadu, IN
2 Department of ECE, Rajalakshmi Engineering College, Chennai - 602105, Tamil Nadu, IN

Abstract

Objective: Spectrum shortage and Inter Cell Interference (ICI) are two factors which limits the performance of wireless cellular networks. Methods/Analysis: One of the popular methods is Soft Frequency Reuse which effectively controls the spectrum management and reduces the ICI for wireless networks. In conventional static Soft Frequency Reuse (SFR) scheme, transmission power in cell and allocation of subcarriers are fixed during the system deployment, which affects the performance of system. Findings: This paper focuses Intercell Resource Allocation algorithm, which is dynamic in nature and optimizes both subcarrier and transmission power for cellular network. Novelty/Improvement: Intercell Resource Allocation algorithm result in greater improvement in data rate and system capacity.

Keywords

Intercell Interference (ICI), Long-Term Evolution (LTE), LTE-Advanced (LTE-A), Soft Frequency Reuse (SFR), Spectrum Management.

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M. Lakshmanan ¹, V. Noor Mohammed ¹, M. Palanivelan ², P. Siva Kumar ¹

Affiliations
1 School of Electronics Engineering, VIT University, Vellore - 632014, Tamil Nadu, IN
2 Department of ECE, Rajalakshmi Engineering College, Chennai- 602105, Tamil Nadu, IN

Abstract

Objective: The design of wireless networks mainly focuses on resource allocation and energy efficient schemes to meet the increasing demands. Methods/Analysis: In this paper, we proposed an algorithm for Resource block (RB) allocation and Transmit power control in Long term evolution (LTE) downlink heterogeneous networks. Findings: Energy efficiency is increased by increasing the number of smaller cells. To satisfy the required user throughput energy efficiency is minimized and suitable resource block allocation is maximized. Novelty/Improvement: In the proposed power control algorithm, user is allowed to select minimum powers to reduce power of Evolved NodeB (eNB).

Keywords

Energy efficiency (EE), LTE, Macro (MeNB), Resource Block (RB), Small eNodeB (SeNB).

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S. Jayanthi ¹, H. Ranganathan ², M. Palanivelan ³

Affiliations
1 Assistant Professor SG, Department of ECE, Saveetha School of Engineering, Chennai, IN
2 Professor, Department of ECE, Jerusalem College of Engineering, Chennai, IN
3 Professors, Department of ECE, Rajalakshmi Engineering College, Chennai, IN

Abstract

MR imaging gives the normal and abnormal anatomy of the brain. MR imaging plays a vital role in diagnosis, localization, quantifying the volume of the tumour and in treatment planning for the radiologists. In this we propose a method for segmentation of tumour regions of brain from a two dimensional (2D) cross sectional magnetic resonance (MR) images. In this an active contour segmentation algorithm is done regions. It uses the hybrid technique of intensity and fuzziness to segment the tumour region. The Flair MR image is used to estimate the whole region of the tumour. The MR images have a complex intensity which will not be able to give a proper segmentation if a single method is used. The segmentation is done without any training dataset. From the segmented results, the Radiologists can find the intensity of whole tumour. This method shows the significant improvement in segmentation compared to manual segmentation.

Keywords

Active Conyour, Brain Tumour, FCM, Magnetic Resonance Imaging, 3D Reconstruction.

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