Informatics Publishing Limited

Rajvirsinh C. Rana ¹, Jagdish M. Rathod ²

Affiliations
1 School of Engineering, RK University, Rajkot - 360020, Gujarat, IN
2 Department of Electronics,Birla Vishvakarma Mahavidyalaya, Vidyanagar - 388120, Gujarat, IN

Abstract

Objectives: To propose an optimal power allocation method for high-speed V-BLAST MIMO-OFDM system for better performance in terms of SNR and BER than the traditional methods. Materials and Methods: To study and evaluate the performance of two linear channel estimators, the Least Square Error (LS) and Linear Minimum Mean Square Error (LMMSE) are used for 4 × 4 VBLAST Multiple input, multiple output-orthogonal frequency division multiplexing (MIMOOFDM) system with different modulation-4 QAM,16QAM and 64 QAM. For power allocation, optimal power is determined by the Greedy Power Allocation and the Cuckoo Search algorithm depending on the condition of the carriers measured from the channel estimation. Findings: Based on the detection method, Vertical Bell Labs Layered Space-Time (V-BLAST) MIMO-OFDM is found to be the high-speed system. Here, the proposed optimal power allocation method for high-speed V-BLAST MIMO-OFDM system showed a better performance in terms of Signal to Noise Ratio (SNR) and BER than the traditional methods. This thesis work has been evaluated based on different channel estimation with different modulation techniques for V-BLAST MMSE MIMO-OFDM System. The test program has been implemented in the latest technology system in Matlab R2013a. The experimental results show that our proposed method achieves better performance in terms of Bit Error Rate (BER) and SNR compared with the existing methods used for improving the performance of the MIMOOFDM. Linear MMSE proved efficient channel estimation technique over LS. MMSE -OSIC achieves very good performance with respect to other detectors in VBLAST MIMO-OFDM environment for 4× 4 MIMO-OFDM systems. Application: This result would be useful to make efficient Adaptive MIMO-OFDM system. It would be also useful in adaptive modulation and power allocation concept for making better wireless communication system. This performance analysis can perform for different channel models.

Keywords

Cuckoo Search (CS) Algorithm, Frequency Division Multiplexing, Greedy Power Allocation, Multiple Input Multiple Output Orthogonal, (MIMO-OFDM), Optimal Power Allocation, Vertical Bell Labs Layered Space-Time (V-BLAST) Detection

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Hemant D. Vasava ¹, Jagdish M. Rathod ²

Affiliations
1 School of Engineering, RK University, Rajkot – 360020, Gujarat, IN
2 BVM Engineering College, Vallabh Vidyanagar, Anand – 388120, Gujarat, IN

Abstract

Objectives: To design Distributed Shared Memory (DSM) for the multiprocessor distributed framework using a different software parametric approach that provides significant performance improvement against convention software based architectures. Methods/Statistical Analysis: Software distributed shared memory can be architected by using a different concept of an operating system, by utilizing a programming library and by extending underlying virtual address space architecture. It incorporates various design options like granularity, consistency model, implementation level, data organization, algorithms, protocols, etc. We have proposed few software parameter choices and impact which gives significant performance improvement compared to past designs to manage software distributed shared memory. This paper also discusses various issues that exist while moving toward software distributed shared memory implementation. Findings: There are two methodologies by which it is possible to achieve distributed shared memory design are first in hardware like cache coherence circuits and network interfaces and the second is software. Here the proposed system architecture makes major impact on programming, performance, design and cost. An algorithm is designed such a unique manner which resides in memory controller and make efficient global virtual memories. It is using variable as granularity which are shared that is more flexible for complex data structure and large database. It is defined using unique identifier which makes its mapping and retrieval more manageable using proposed consistency mechanism. Application/Improvements: Distributed shared memory optimization is a most important area of improving distributed system performance. By taking care of good choice on underlying issues and according to system’s design requirement, it possible to gain advantages of improved architecture which can be more used for various distributed applications where shared data plays a major role.

Keywords

Distributed Shared Memory, Distributed Systems, Granularity, Interprocess Communication, Virtual Address Space

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