P-RAN, an Indoor Solution for 5G and 6G in High Frequency Bands

With the progress of 5G commercial deployments worldwide, indoor coverage becomes a new issue because of the use of high frequency bands. While traditional distributed antenna systems (DAS) are available to mitigate the indoor coverage problem, service providers are reluctant to use them due to the required zoning and civil engineering difficulties in addition to the required higher capital expenditure (CAPEX). Device to device (D2D) technique has been proposed since Release 12 of LTE for cellular communications. Unfortunately, the commercial capabilities of D2D using the Side-Link standard have not been available in smartphones due to the lack of needed support from any of the major operators. In this article, a launch of new services using D2D capabilities of smartphones will be discussed to mitigate the indoor coverage problem. This would mark the first time when one of the world major operators has provided a material support for the capabilities. If this effort can be fruitful, it can be a paradigm shifting approach for the indoor coverage problem and may pave the way for the D2D capabilities to be implemented into smartphones for many possible proximity services in the future.