Frequency Projection: A Review and its application in channel modelling

Frequency projection is an idea of leveraging the channel-related parameters in one frequency band to estimate its counterpart in the other. This phenomenon applies to many applications such as Frequency Division Duplex (FDD) systems where uplink and downlink are operated in different frequencies, exploiting frequency correlation between the underlay and overlay wireless networks for 5G/B5G Wireless Communication, multi-band chipsets, etc. This paper presents a review of the key frequency projection-based application and innovations over the last three decades. Also, its application in channel modelling of Non-Terrestial Network (NTN) is presented with simulation results. A scope for new work on this interesting topic is also argued in this contribution.