As Voice over LTE still lacks the QoS required and supported by 2G, globally, most operators are
currently using their 4G / LTE network for pure data and switching to the existing 2G/3G networks for voice calls. The following chart shows LTE Spectrum Band allotted in various countries and How Operators are Offering Voice Services. 
There are 3 options for Reliance Jio to offer Voice – 1) Use its LTE network, 2) share spectrum with an existing operator or 3) acquire an existing operator.
We believe that challenges exist in offering voice using LTE network. In case of Reliance Jio Infocomm, the 2300MHz band is spectrally inefficient, especially for voice. Even for data, the capex implication will be high in case the company decides to have a relatively wide coverage using this spectrum band.
The remaining two options are likely to involve high entry cost which should curtail any disruptive behavior by Reliance Jio. TRAI recommendations on Spectrum Sharing suggest, operators that have paid the market price of spectrum (based on the auction prices) should be permitted to share spectrum without any additional one-time charge. It is currently silent on the non-liberalized spectrum but we should expect that any spectrum sharing would be allowed only after the operator pays the market price of spectrum – currently stands at $2 Bn for 5MHz pan-India spectrum in 1800MHz band. Even if Reliance Jio undertakes spectrum sharing with Reliance Communications, there would be significant cost implications for the parties involved.
Acquiring an existing operator will also involve high cost. Licensing 2G Voice as an MVNO may find favor since the M&A rules in the industry are not yet clear. Reliance Jio will not impact the A-Vo-Id cartel in the short-medium term but maybe case some turbulence in the long run.
Reliance Jio has a very high level of influence in policy making [Acknowledged by the Chairman, Mr. Mukesh Ambani himself stating “Congress Apni Dukaan Hai”] in the current potentially highly corrupt Government of India headed by Politicians of the Congress Party. Against this backdrop, expect some level of policies favoring Reliance Jio when it comes to Telecom Spectrum.