Millimeter Wave Communications

Abstract

Millimeter wave (mmWave) technologies promise to revolutionize wireless networks by enabling multi-gigabit data rates. However, they suffer from high attenuation, and hence have to use highly directional antennas to focus their power on the receiver. Existing radios have to scan the space to find the best alignment between the transmitter's and receiver's beams, a process that takes up to a few seconds. This delay is problematic in a network setting, where the base station needs to quickly switch between users and accommodate mobile clients.We present Agile-Link, the first mmWave beam steering system that is demonstrated to find the correct beam alignment without scanning the space. Instead of scanning, AgileLink hashes the beam directions using a few carefully chosen hash functions. It then identifies the correct alignment by tracking how the energy changes across different hash functions. Our results show that Agile-Link reduces beam steering delay by orders of magnitude.

A Comprehensive Study of Low Frequency and High Frequency Channel Correlation

“…In the next chapter, we will be focusing on how to overcome some of these limitations by reducing the Beamforming (BF) overhead. this can take seconds [28,29], although this can be reduced to milliseconds [30]. Since mmWave has gigabit per seconds communication links, even a short downtime period has an extreme impact on channel quality.…”

ML-Enabled Millimeter-Wave Software-Defined Radio with Programmable Directionality

“…The mmWave antenna beam direction can be steered mechanically or electronically. Older mmWave platforms mechanically steered horn antennas to align the transmit and receive beams [23]. Today, more advanced patch antenna array systems are used to electronically steer the beams.…”