The impact of highly reflective ceilings on wireless systems in occupied open plan offices

Improving the reliability and coverage of indoor wireless systems is an important design goal. A highly reflective ceiling creates an elevated image of the access point, which delivers a strong and reliable multipath component to the mobile terminal. Measurement results show that a small area of metallic ceiling above the transmitter can provide significant enhancement to the received signal power across a large room. Experiments with human bodies obstructing the line-of-sight path were performed to further examine the effectiveness of such an architectural modification. The improvement can be as high as 6.5 dB in cases where the line-of-sight path is obstructed by a human body. Moreover, the effectiveness of the metallic ceiling does not diminish with the distance from the transmitter. A comparison of measured and simulated results shows that ray tracing simulation can adequately approximate the results observed by measurement at 5.8 GHz.