Sampling and FFT Size derivation in LTE Ts = 1 / (15000 x 2048) seconds, which corresponds to the 30.72 MHz sample clock for the 2048 point FFT used with the 20 MHz system bandwidth. In the frequency domain, the number of sub-carriers N ranges from 128 to 2048, depending on channel bandwidth with 512 and 1024 for 5 and 10 MHz, respectively, being most commonly used in practice. The sub-carrier spacing is ∆f = 1/T u = 15 kHz. The sampling rate is fs = ∆f · N = 15000 N. This results in a sampling rate that’s multiple or sub-multiple of the WCDMA chip rate of 3.84 Mcps: LTE parameters have been chosen such that FFT lengths and sampling rates are easily obtained for all operation modes while at the same time ensuring the easy implementation of dual-mode devices with a common clock reference. Sampling frequency is Multiple's of 2, For 15 Mhz Bandwidth - Sampling Frequency = 23.04 (6 * 3.84). FFT SIZE = S
