Small-Holder Farmers^ Cooperative Communication Systems Using Virtual MIMO (Multiple Input and Multiple Output) Method: Concept and Application Chelsea V. Useng (a), Daniel Useng (b*), Yoedy Moegiharto (a), Arifin (a), H. Mandalika (a), M.T. Sapsal (b)
(a) Surabaya Polytechnique of Electronics (PENS),
(b) Dept. of Agricultural Engineering, Hasanuddin University.
*) Corresponding author: daniel.useng[at]agri.unhas.ac.id
Abstract
This article is the first of two-stage research in collaborative communication systems applying the IoT. The first stage is the concept of a cooperative communication system using MMSE (Minimum Mean Square Error) and the second stage is the application of a cooperative communication system among small-holder farmers in order to optimize the interactions among rural farmers.
The concept of first step is that the development of telecommunication technology which continues to increase in wireless media cannot be avoided. This system sometimes suffers from the effect of multipath fading which reduces the performance of the transmission system and results in low-quality of received data. The cooperative communication system is a virtual MIMO (Multiple Input and Multiple Output) system that implements multiple antennas on the transmitter and receiver sides and the addition of relays to work together to process signal transmission to reduce fading effects. In addition, the MIMO-OFDM signal detection process requires knowledge of channel conditions. The dynamics of this adaptive channel estimation principle are by adjusting the weighting based on the error value of the estimator output and the reference signal (actual signal). With the weighting value that is continuously updated, it is expected to be able to follow changes in the channel response. One of the channel estimation methods is the MMSE method which can take advantage of the spatial correlation of MIMO channels.
This research is based on research by Yazlin et.al (2013) on the performance of cooperative communication systems using the AF (amplifying and forward) technique with QPSK (Quadrature Phase Shift Keying) modulation. Based on this method, we try to continue research that builds a system for implementing the MMSE channel estimation technique for OFDM (Orthogonal Frequency Division Multiplexing) signals applied to a cooperative communication system using the DF (Decode and Forward) protocol (Stage 1).
Performance results were analyzed through simulation with Matlab software in terms of Bit Error Rate and Mean Square Error as a function of Signal Noise Ratio (SNR). The results expected to be used as a role model tool in terms of wireless communication using the MMSE OFDM channel estimator technique in cooperative communication systems and to be applied among small-holder farmers in the future (Stage 2).
Keywords: OFDM, MMSE, MIMO, Estimator, cooperative communication
