On the use of indoor radio environment maps for hetnets deployment

This work analyses the feasibility of building an indoor Radio Environment Map (REM) for supporting the deployment of indoor small cells acting as secondary transmitters in the TVWS band. For that purpose, it proposes a structure of the REM database for computing the maximum allowed transmit powers not to interfere with TV receivers. The proposed framework is validated by means of real measurements. Results include the analysis of the spatial granularity and time stability of the measurements, and the maximum allowed transmit powers considering both co-channel and adjacent channel transmission, as well as the existence of other secondary transmitters. Results reveal that in the considered building small cell deployment using co-channel transmission is not feasible due to the very low resulting allowed transmit powers. However, when adjacent channel transmission is considered, the resulting maximum allowed power levels can be more adequate for successful small cells deploy-ment.