Hi feras,
in case of LTE, greater the bandwidth, the greater the channel capacity. There are different channel bandwidths LTE are: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz. If the subcarriers spacing is 15 kHz, i.e. the LTE subcarriers are spaced 15 kHz apart from each other. To maintain orthogonality, this gives a symbol rate of 1 / 15 kHz = of 66.7 µs.
Each subcarrier is able to carry data at a maximum rate of 15 ksps (kilosymbols per second). This gives a 20 MHz bandwidth system a raw symbol rate of 18 Msps. In turn this is able to provide a raw data rate of 108 Mbps as each symbol using 64QAM is able to represent six bits.
accordingly you can choose as per the design.
Regards,
Dhiman