One of the unique aspects of LTE is the support of the six channel bandwidths from 1.4 MHz to 20 MHz. To simplify system operation and roaming phones should support all these bandwidths, although effective deployment in any one area may be limited to fewer band width 20 MHz LTE is significantly larger than the widths maximum bandwidth of other cellular systems today.
Therefore, when designing the recipient’s attention to the amplitude and phase flatness is required. Filters, amplifiers and mixers in particular must now work properly on multiple channel bandwidth.
The structure of the LTE signal has a reference signal (RS) which are arranged in both frequency and time throughout the LTE signal. ENB and the UE receiver may use such signals and digital signal processing (DSP) techniques to compensate for amplitude and phase errors in the receiver linearity. Flatness needs to be tested in each supported bandwidth and the band, in particular at the band edge where the edge of the duplex filter attenuates the signal.