Two adaptive dedicated channel allocation algorithms, namely dynamic dedicated channel partitioning ( ${D^2}CP$) and dynamic dedicated channel partitioning with cooperation (${D^2}CP{-}C$), were proposed in [1] to improve the system throughput of ultra-dense networks (UDN). However, due to the incorrect use of the geometric–arithmetic mean inequality theorem, the average system throughput could not be guaranteed to be optimal. In this letter, we study the proposed ${D^2}CP$ and ${D^2}CP{-}C$ algorithms in UDN and deduce the average system throughput. Consequently, we prove that the equal resource allocation strategy proposed in [1] is strictly not optimal.