iphone 5 Enable LTE

I have Iphone 5 here in Oman. But there is no any option of Enable LTE in cellular settings. Why is it so? Mobile Operators have LTE services and my SIM is also privisioned with LTE.\

I cannot see an option of "Enable LTE" at all ......

Carrier Supports LTE for iPhone 5 - Middle East 3 Country Supports UAE,Saudi Arabia,Kuwait but Oman ( omantel ) ?