There are total 6 channel bandwidths used in LTE.
1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz.
There are a new feature in LTE advanced called ‘Carrier Aggregation’ in which LTE network can aggregate up to five carrier component. If a LTE network aggregating five 20 MHz carrier component then it would become 100 MHz bandwidth.