Field Trial Results of a 4X4 MIMO-OFDM Real Time Testbed

The results of a field trials campaign in a park, a wide street, a narrow street and office environments are presented in this paper. The trials are carried out using a real time 4×4 MIMO-OFDM testbed working in the 2.4 GHz ISM band and a 20 MHz bandwidth. The testbed supports both spatial multiplexing and transmit and receive diversity. We compare the system performance using different number of spatial streams in different environments. We also determine the maximum number of spatial streams that can be supported in the indoor and outdoor environments respectively. We found that the maximum achievable throughput for the system in the indoor environment is almost double the maximum achievable throughput in the outdoor environment at the same receive power. This is mainly due to the richness of scattering elements in an indoor setting. Our outdoor trials showed that supporting more than two spatial streams will not introduce any throughput gain.