There has been an increasing interest in the millimeter wave (mmW) frequency regime in the design of the next-generation wireless systems. The focus of this paper 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 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. Toward 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 gigahertz are reported. Finally, implications of these measurements on system design are discussed, and multiple solutions are proposed to overcome these impairments.
