Prediction of variation in MIMO channel capacity for the populated indoor environment using a radar cross-section-based pedestrian model

摘要

[Abstract]: Multipath propagation is a fundamental requirementfor the operation of multiple-input multiple-output (MIMO)wireless systems. However, at ultrahigh frequency (UHF) andabove, pedestrian movement may significantly affect the multipathpropagation conditions in indoor environments. For the firsttime, a systematic analysis of the effect of pedestrian movementon channel capacity for an otherwise line-of-sight MIMO link in asingle room is presented. A novel channel model for the populatedindoor environment is also introduced, based on geometricaloptics and a detailed radar cross-section representation of thehuman body. The new model generates a temporal profile for thecomplex transfer function of each antenna combination in theMIMO system in the presence of specified pedestrian movement.Channel capacity values derived from this data are important interms of understanding the limitations and possibilities for MIMOsystems. Capacity results are presented for a 42-m2 single roomenvironment, using a 2.45-GHz narrowband 8 8 MIMO arraywith 0.4 element spacing. Although the model predicts significantincreases in the peak channel capacity due to pedestrian movement,the improvement in mean capacity values was more modest.For the static empty room case, the channel capacity was 10.9b/s/Hz, while the mean capacity under dynamic conditions was12.3 b/s/Hz for four pedestrians, each moving at the same speed(0.5 m/s). The results presented suggest that practical MIMOsystems must be sufficiently adaptive if they are to benefit fromthe capacity enhancement caused by pedestrian movement.