Informatics Publishing Limited

J. Hemalatha ¹, R. Palani Kumar ¹, K. Ramasamy ²

Affiliations
1 P. S. R Engineering College, Sivakasi, IN
2 P S R R College of Engineering for Women, Sivakasi, IN

Abstract

A Wireless Sensor Network (WSN) is a network composed of a large number of nodes that sense, collect, transmit, and deliver data to where it is needed. It involves set of isolated urban areas covered by sensor nodes (SNs) monitoring environmental parameters. Mobile sinks are mounted upon urban vehicles with fixed trajectories (e.g., buses) providing the ideal infrastructure to effectively retrieve sensory data from such isolated WSN fields. Existing approaches with single hop transfer of data from SN that lie within MS range and heavy involvement of network periphery nodes. In Existing Mobicluster Protocol used with Rendezvous sensor nodes for minimizing the overall network overhead and energy expenditure. This protocol use fixed MS track that have no special focus on amount of data that leads to very long delivery delay. Our proposed protocol KNN employs dynamic path selection which is very flexible increases energy reliably and efficiently compared to the previous approach. Hence this protocol aims at achieving overall network overhead reduction, energy consumption and prolonged network lifetime.

Keywords

Wireless sensor networks, Rendezvous nodes, Mobile sink, Nearest neighbor

Full Text

     

R. Suresh Babu ¹, M. Suganthi ², K. Ramasamy ³

Affiliations
1 Department of Electronics and Communication Engineering, Kamaraj College of Engineering and Technology, Tamil Nadu, IN
2 Department of Electronics and Communication Engineering, Thiagarajar College of Engineering, Tamil Nadu, IN
3 Department of Electronics and Communication Engineering, P.S.R.R.College of Engineering for Women, Tamil Nadu, IN

Abstract

Present wireless communication systems uses FDMA, TDMA and CDMA techniques and are facing various issues like multipath fading, time dispersion which leads to inter symbol interference (ISI), lower bit rate capacity and less spectral efficiency. In a conventional terrestrial broadcasting, the transmitted signal arrives at the receiver through various paths of different lengths. Hence multiple versions of the signal interfere with each other and it becomes difficult to extract the original information. The use of Space Time Block Coded (STBC) Orthogonal Frequency Division Multiplexing (OFDM) technique provides better solution for the above issues. In this paper, we study the Bit Error Rate (BER) performance of STBC OFDM system employing BPSK, QPSK and QAM modulations. As STBCs have been derived from Generalized Complex Orthogonal Designs (GCOD), the norms of the column vectors are the same (e.g., Alamouti Code). We present an analysis of how multiple transmitting antennas and one receiving antenna produces reduced BER at lower value of SNR. From the simulation results, we observed that the BPSK allows improved BER performance over a noisy channel at the cost of maximum data transmission capacity. But the use of QPSK and QAM allows higher transmission capacity at the cost of slight increase in the probability of error.

Keywords

Generalized Complex Orthogonal Design, Space Time Block Code, Alamouti Code, OFDM, Antenna Diversity.

Full Text