5G mmW receiver interoperability with Wi-Fi and LTE transmissions

Abstract

<div lang="en" class="abs"><p class="abs_header">Abstract</p><p>New interoperability problems will arise, when 5G millimeter wave (mmW) radios will be integrated into mobile devices and small cell base stations with other radios. Current LTE (Long Term Evolution) and Wi-Fi radio transceivers have not been designed, verified or specified for simultaneous operation with 5G mmW radios. Wi-Fi or LTE-LAA (Licensed Assisted Access) may introduce co-channel interference due to the harmonics falling over 5G mmW frequencies. Alternatively, the fundamental LTE or Wi-Fi transmission may block the 5G mmW receiver. This paper studies requirements for RF filtering in the LTE and Wi-Fi radios, which operate in conjunction with a 5G mmW system. Antenna isolation measurements of 5G proof-of-concept (PoC) antenna array show that mmW antenna array resonates with multiple lower frequencies due to the antenna array physical dimensions, e.g. overall module dimensions, sub-array dimensions and sub-array locations from the edges of the antenna module. Thus, lower frequency interoperability is a new optimization criterion for dimensions of mmW antenna module. Measurement results verify that a previously developed 5G mmW PoC radio and antenna module operating at 28 GHz and LTE-LAA/Wi-Fi operating at 5 GHz as well as LTE at 2.7 GHz can operate simultaneously without interference problems within the same radio unit.</p></div>