  There has been an increasing interest in the millimeter wave (mmW) frequency
regime in the design of next-generation wireless systems. The focus of this
work is on understanding mmW channel properties that have an important bearing
on the feasibility of mmW systems in practice and have a significant impact on
physical (PHY) layer design. In this direction, simultaneous channel sounding
measurements at 2.9, 29 and 61 GHz are performed at a number of
transmit-receive location pairs in indoor office, shopping mall and outdoor
environments. Based on these measurements, this paper first studies large-scale
properties such as path loss and delay spread across different carrier
frequencies in these scenarios. Towards the goal of understanding the
feasibility of outdoor-to-indoor coverage, material measurements corresponding
to mmW reflection and penetration are studied and significant notches in signal
reception spread over a few GHz are reported. Finally, implications of these
measurements on system design are discussed and multiple solutions are proposed
to overcome these impairments.
