Channel Feasibility for Outdoor Non-Line-of-Sight mmWave Mobile Communication

Due to the scarcity of spectrum below 3 GHz for wireless communications, there have been proposals to explore millimeter wave (mmWave) spectrum (3- 300 GHz) for commercial mobile applications. MmWave spectrum provides unique advantages such as availability of GHz bandwidth and use of antenna arrays with beamforming to compensate for path loss. While there exist well-established models for mmWave indoor non-line-of-sight (60 GHz) and mmWave outdoor line-of-sight (backhaul) communication, mmWave channels for outdoor, non-line-of-sight, mobile communication have not been explored sufficiently. We present penetration and reflection measurements for different materials and line-of-sight and non- line-of-sight measurements for outdoor mmWave mobile communication. We find that while well-known lossy objects such as human body and concrete can have poor penetration, they are good reflectors at these frequencies, enabling the receiver to capture secondary reflections for non-line-of-sight communication. We also show that a wide beam width, low gain antenna at the mobile receiver can capture more energy in scattered non-line-of-sight environments and thus, can provide more gain than a narrow beam, high gain antenna for mobile communication. Our initial measurements motivate utilizing mmWave frequencies for outdoor non-line- of-sight mobile communication.