Off-body data communication for firemen and other rescue workers is an important area of development. The communication with a moving person in an indoor environment can be very unreliable due to the channel fading. By transmitting and receiving signals using multiple antennas (MIMO communication) a large improvement of the reliability of the wireless link is obtained. The performance of wireless data communication using space-time block codes for firemen walking indoor and communicating through dual polarized textile patch antennas integrated in their clothing is evaluated. A measurement with a walking test person is performed with both transmit and receive diversity of fourth order. The Kronecker and eigenbeam MIMO channel models are applied to the measured signal levels and bit error rate characteristics are derived for the measured and modeled channels. All measurements were performed in the 2,45 GHz ISM-band using on-body textile antennas of a convenient size.