The IEEE802.11ac task group has announced the use of a wider channel that extends the channel bandwidth to more than 80 MHz. We present an experimental platform consisting of a baseband and a RF unit in a 22 MIMO-OFDM system for the wider channel and report its system performance results from a field experiment. The MIMO-OFDM transceiver in the baseband unit has been designed to detect real-time MIMO and provides a maximum data rate of 600 Mbps. OFDM tends to cause high peak PAPR for wider channels and distorts the power amplifier performance in the RF unit. We have improved the non-linear distortion by optimizing the OFDM preamble and evaluated its performance by conducting a simulation integrated with baseband processing and a RF. In the field experiment, our platform tested the communication performance in a farm and a passage environment.