Not able to connect Nexus 7 2013 to 3g network in inda

I have purchased a Nexus 7 2013, 32 GB , wifi+ LTE model , but i am not able to connect it to 3G network of Tata Docomo in India. I tired with Vodafone , the same result.

with Tata Docomo 3G network ( a micro sim is used), the message comes, Sim is not allowed to connect to network while carrying out the registration to network.

When i start the device, it recognized the Docomo network, not not signal is visible in the top left corners.

Can anybody help me how to do. Search in net has revealed that i need to change the setting of network from LTE to WCDMA. how this option is not available on Nexus 7 2013 cellular model