Airtel’s 4G services, the trials of which premiered about a month ago, are currently incompatible with the bandwidth supported on Apple’s top-of-the-line iPhone 6 and 6 Plus. The TDD form, on which the LTE connectivity is being provided in the Delhi NCR circle by Airtel, is incompatible with the iPhones, and has deemed them invalid to connect to Airtel’s LTE, as of now.
TDD, the Time-Division Duplex of LTE, provides connectivity on 2300MHz frequency band, while FDD (Frequency-Division Duplex) provides connectivity on 1800MHz frequency band. The iPhone 6 and 6 Plus models A1549 and A1522 on GSM and CDMA networks connect to LTE networks via bands 1-29, which fall within FDD bandwidth. Airtel, who first initiated 4G services in Kolkata back in 2012, had been initially rolling out 4G connectivity on FDD bandwidth. Recently, it started beta-testing TDD bandwidth network in a number of cities, including Delhi NCR.
Initially, Apple had rolled out an upgrade to make the Indian versions of the iPhones 4G-compliant. The models A1586 and A1524 of the iPhone 6 and 6 Plus support LTE bands 38-41, which are TDD-based networks. Unless your iPhone happens to be one of these models, you will not be able to connect to Airtel 4G, which, as mentioned above, is on TDD bandwidth. There is little or no possibility of any firmware upgrades to make the devices compliant to the higher frequency bandwidth, since these happen to be the global differentiation within iPhone models.
Notably, relatively cheaper handsets by manufacturers like Samsung, Xiaomi and the likes are all compliant to the TDD bandwidth network that Airtel is providing. Service providers like Vodafone and Idea Cellular are launching LTE network trials in India soon, and will be providing connectivity via FDD bandwidth, which would enable the iPhones to connect to 4G.
Apple has recently reported a large growth of iPhone sales in India, and also shown growing interest in the Indian market by premiering Apple Music in India along with its global release. iPhone’s manufacturers, Foxconn, have also been reported to be considering setting up manufacturing and assembly plants for Apple in India by 2020, thereby presenting a prospect of bringing down the prices of Apple products by a fair margin.