An Overview on Beamforming and its Issues for 60 GHz Wireless Communications

In recent days, the unlicensed millimeter (mm) wave spectrum in the 60 GHz band is becoming a promising technology for multi-gigabit wireless communication. Compared to other lower frequency systems, the spectrum around 60 GHz holds several advantages including huge unlicensed bandwidth (upto 7 GHz), compact size of transceiver due to small wavelength (about 5 mm) and less interference owed by high atmospheric absorption. However, there are several challenges associated with this spectrum, such as reflection and scattering losses, high penetration loss and high path loss, which limits the range of coverage at 60 GHz. The 60 GHz links in indoor environment is also susceptible to line of sight (LOS) blockage due to its lack of ability to diffract around various objects. To overcome all these challenges, directional transmission is very vital. Thus, a technique known as beamforming utilizing multi-element antenna arrays is considered important for 60 GHz wireless communication. This paper focuses on providing a general understanding of beamforming and its techniques at 60 GHz and reviews the various issues associated with it.