Hi,
A number of factors influence the ideal cell load value as more often than not it can be subjected to a number of direct and indirect factors. Network deployment, user density, user traffic and usage times can be looked as some parameters that make it strenuous to determine the ideal value.
For references, research papers, journals and latest reports published by telecommunication companies can be looked at good sources. Additonally, The 3rd Generation Partnership Project (3GPP) is responsible for defining the specifications for mobile communication systems, including 5G. The 3GPP technical specifications and reports provide detailed information about various aspects of 5G networks, including cell load.
