Let me clear you about Wi-Fi.
Wi-fi uses IEEE 802.11 routing protocol.
It is a non-profit international organisation which created a standardised rules for Wireless devices.
The main aim was to provide a low cost wireless devices , There are several brands in wireless devices. Ex:Routers or Modem what we are using.
But they have to follow a standard set of rules so that its compatible with users requirements & accepted globally.
LTE:(Long Term Evolution)
LTE is a 4th Generation networking device which uses low power and throughput(output) is more in terms of network reliability.
And what we are using these days in Datacard is Wimax, which is actually outdated in the world.
And all other countries are using 4G which is faster & reliable.
WIMAX: Its an alternative to wired broadaband what we have currently.
What i can say is the data card from Huwaei which BSNL is providing is the best example.
The good thing about wimax is they don't require a dedicated hardware, they are usually configured by software drivers.
Broad Band Wireless Access (BWA) is a technology which is using Wimax technology.
In this the deployment costs for company will be less .
It uses 3G technology.
Right now 3G technology using WIMAX is latest in India.
WIMAX,3G,4G are all wireless based devices.
Wifi is just a standard and all these sub devices are working with different protocols.
Ex:Wifi-802.11
Wimax-802.16