What is channel bandwidth in LTE?

In 3GPP the channel bandwidth is defined as the occupied bandwidth of a modulated waveform which corresponds to the frequency range containing 99% of the total power of the modulated signal . An LTE-M-U narrowband of 6 PRBs have a 1.4 MHz channel bandwidth according to this definition which is reused by ETSI.

A. The amount of bandwidth allotted to each channel in a communications system that transmits multiple frequencies such as fiber optics . It is measured as the spacing between center frequencies (or wavelengths) of adjacent channels.

Channel spacing, also known as bandwidth, is a term used in radio frequency planning. It describes the frequency difference between adjacent allocations in a frequency plan .