Characteristics of indoor millimeter-wave channel at 60 GHz in application to perspective WLAN system

This work presents results of the investigation of indoor millimeter-wave channel at 60 GHz in application to perspective WLAN systems. The results are based on the work of the authors on the IEEE 802.15.3c (60 GHz WPAN) and IEEE 802. Had (60 GHz WLAN) channel models development. It is demonstrated that 60 GHz indoor propagation channel has a quasi-optical nature and that WLAN systems have to use steerable directional antennas steered along a LOS or low-order NLOS reflected path to be able to operate in typical indoor environments. A single channel cluster (path) is shown to be composed of multiple rays that results in significant frequency selectivity of the channel even if high-directional steerable antennas are applied. It is demonstrated that diffraction mechanisms are not essential for 60 GHz WLAN systems due to quasi optical nature of the propagation channel. Polarization characteristics of the antennas and the propagation channel for 60 GHz band were found to be significantly more important than for the legacy WLAN bands of 2.4 GHz and 5 GHz. The degradation due to polarization characteristics mismatch between the antennas and the propagation channel for a 60 GHz WLAN system may be up to 10-20 dB.