In particular, LDPC codes exhibit an asymptotically better performance than turbo codes and admit a wide range of trade-offs between performance the following site and decoding complexity [13]. Sartipi and Fekri [14] compare the performance of the LDPC codes and the Reed Solomon (RS) codes [15]. From the recent works, it is known that LDPC codes are attractive in WSNs because of their applications in compression, joint sourcechannel coding and distributed source coding [14,16]. However, to the best knowledge of the authors, there has been no document on the implementation of LDPC encoder/decoder in a wireless sensor node using cooperative communication. More precisely, none of the recent works have addressed the problem of reducing the energy consumption using error control coding.
In this paper, LDPC code is incorporated in cooperative communication as an error control code. Later the idea is compared with SISO communication. In Section 2, the system model is shown and the error correction using LDPC code is analyzed in Section 3. Section 4 shows the energy model for both cooperative MIMO and SISO considering error correction codes. In Section 5, simulation results are shown and discussed. Finally, Section 6 concludes the paper.2.?Cooperative MIMO Communication2.1. System ModelThe system model for C-MIMO communication is a centralized wireless sensor network where there is a data gathering node (DGN) and several clusters with several sensors in each cluster. Sensors in one cluster transmit the data to the sensors in adjacent cluster and step by step the data reach the DGN.
Figure 1 shows the cluster to cluster communication where two clusters are shown. The system considers Nt number of sensors in the transmitting cluster, Nr number of sensors in the receiving cluster and one antenna is placed at one sensor. Also, each element in the channel matrix H is assumed to be a zero-mean circularly symmetric complex Gaussian random variable with unit variance and can be considered as follows.H=(h11h12��h1Nrh21h22��h2Nr????hNt1hNt2��hNtNr).Figure 1.System model for cluster to cluster communication in wireless sensor network.The problem here is stated from the receiver point of view, so a loss model is used to estimate the received energy. To calculate the total energy consumption, both the circuit and transmitter power are taken into count. The same transmitter and receiver blocks shown in [4] are used in this paper. Source coding, pulse shaping, and modulation block are as well omitted from the design. Throughout the paper, a system with narrowband, frequency-flat Rayleigh Batimastat fading channels and perfectly synchronized transmission/reception between wireless sensor nodes is assumed. The fading http://www.selleckchem.com/products/CP-690550.html is assumed constant during the transmission of each frame.