Construction and Interpolation of a Multi-frequency Radio Map

A radio map can be generally defined as a database which contains comprehensive information of radio propagation channel parameters. Due to local spectrum regulations, radio map operators may be unable to transmit radio waves at certain frequency bands, thus preventing the construction of radio maps through direct measurements. This paper proposes a regression-based method to predict the radio map at an arbitrary center frequency using a multi-frequency radio map. A measurement campaign was conducted in a university campus, where radio maps at two center frequencies were utilized to predict the radio map at a different frequency. Results showed that the proposed technique could achieve a root mean squared error (RMSE) of about 2:5 dB on average, which is roughly 5 dB lower than the RMSE when using conventional techniques.