Abstract

The channel is a transmission medium between sender and receiver. In wireless communication system, channel is the important one that determine the quality of sending process between sender and receiver. There are several factors that determine the quality of wireless communication due to channel influence, among of them are the amount of noise in the channel, attenuation, also the amount of multipath that are used by the user, so that there is attenuation as known with multipath fading. This phenomena can destroy the signal, so that the signal shape can be change from the original signal.The multipath fading is the phenomena of signal degradation due to the signal from the sender across multipath channel. The path is could be direct path, reflected path, or the signal that has been attunuated by spesific material, such as glass or wood. The use of OFDM technique can be minimilize the influence of multipah fading phenomena. OFDM is a higher data transmission technique using several carrier signal. Meanwhile the MIMO is a technique in processing signal use several antennas, both in the sender and receiver. The purpose of using multi-antenna technique is to maximize the data transmission process to the receiver, so that the incorporation of MIMO-OFDM technique can be provide a high bit rate transmission service, also minimilize the influence of multipath fading. In the process of data detection in the receiver side needs the role of the channel estimation process. The change of channel condition every time resulted in the need of estimation channel process in the receiver interface side. One of the method that can be used in this research is using invers matrix technique. Many antenna usage pattern in the sender and receiver side can be patterned in the form of a matrix. So that, the channel estimation using one of the technique in matrix that is invers matrix can be used. The output of this research is to compare the influence of adding OFDM technique in the estimation channel process using invers matrix method in the MIMO system. From the simulation results show that the estimation channel system using invers matrix method without OFDM technique, the system can be generate zero error (no error in channel estimation). This situation occurs when the noise is set to 12 dB. It means the MIMO system without OFDM can stand until the noise of 12 dB. Meanwhile in the MIMO system with adding OFDM technique can be generate the zero error when the noise is set to 15 dB

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