IMS is more notorious in the telecom world than any other technology for the last several years. A simple quote from a vendor will easily run into a few million dollars for a barebone solution with a business case which relies on passionate optimism than any real success. While fixed line operators successfully implemented the technology and benefited from it in terms of low cost and feature-rich applications, the mobile world is coming to terms with it now. For the last several years, mobile operators like Deutsche Telekom and Vodafone made small implementations both hosted and in-house in the hope that applications running on it will someday have enough revenues to justify the investment. Most of the implementations died in vain with dead business cases, while a few lived on to tell their story as innovative and intelligent platforms on which future operator successes could be built. Operators world over love to call themselves as different- most as innovators than as low cost. However in the struggle of spectrum auctions, regulatory requirements, running the network, M&As and changing technology landscape, few successfully execute beyond talk. Every application launched by an operator in the last few years that competed with an over the top player begged the question of interoperability between operators, locally and globally and none so far succeeded. And none probably will.
Without ado, IMS is right on their face now because Voice on LTE will be several billion dollar businesses and IMS is required of it. So the big question is what’s going to happen.
Broadly the IMS question has 3 key parts to it- Voice for both current GSM and CDMA operators, applications like Rich Communications Suite and others, and then fixed-mobile convergence.
This write up covers all three aspects of IMS and what is likely going to happen on each of these

VoLTE
In this area lead has been taken by Korean operators SK Telekom and LG U+ and US CDMA operators Verizon and Metro PCS who are anticipating fewer handsets from vendors as the technology phases out. European countries such as in Scandinavia who were pioneers in LTE launch way back in 2007 are a bit of a laggard due to slower adoption of LTE. Countries like the UK and Italy are now slowly rolling out LTE but the mindset is more to sweat WCDMA investment before jumping on LTE.
Technical challenges apart the biggest question for US operators are two-fold. Mobile broadband as its forecasted to grow will break all records of consumption in which case operators will have to re-farm their 2G, 3G networks for LTE. What will happen to voice then? Secondly, as mobile broadband becomes pervasive OTTs like Viber and Skype will further strengthen their business, seriously hurting operator’s voice revenues, which along with SMS comprise 70% of operator revenues today.
At this point, I also want to dispel the myth that Voice on CS-2G, 3G is cheaper than Voice on data, from spectrum utilization or radio perspective, for the simple fact, that CS voice takes 10-15 times more spectrum than similar speed on data. Or the same number of users that can be supported by 5 Mhz spectrum for voice can avail themselves of 10-15 times more equivalent speed on data. Further, LTE can support 3 times more users on voice WCDMA and 6 times more than 2G.
Coming back to the two points, on why the operators will have to move to VoLTE and hence IMS, I believe the sense of urgency will come from point one. Operators have miserably failed in the past to really tackle OTT and in this case, whether due to regulatory or business alacrity issues they will not be able to stop Viber and Skype. However, mobile broadband will necessitate operators to refarm 2G, 3G and give an alternative for voice through VoLTE and hence IMS.
Other benefits like HD Voice, lower call set up time, jitter etc. will follow.
Nonetheless, operators will claim that they successfully thwarted the OTTs. That’s the nature of the business, unfortunately.

RCS and Applications
Anyone and everyone in hardware business whether its device, Switch, IP or server manufacturer knows that future growth lies in applications and software. And telecom operator knows it too. But for reasons known and unknown, none of the operators attempts made in the past such as Vodafone 360, INQ, social networks, music and video services have come anywhere close to Facebook, Spotify, Deezer et al. What operators have become the smartest is in bundling and pricing.
Rich communications suite which offers, instant message, chatting, file sharing, network address book, voice and video chat has been around for some time and now has gained a new impetus given the IMS implementations required of VoLTE. Unlike the past, led by Vodafone; DT, FT, Telefonica, TI, and others have come together to launch an interoperable service called Joyn backed by GSMA. Joyn is called RCSe which means it is without presence. So far launches have happened in Spain, South Korea, and Germany with handset vendors supporting the initiative. Interestingly Zain in Quwait plans a trial, supported by cloud capacity provided by Vodafone. The point is that there has been no real impact, though it has been at least a year or so for this initiative and at least 4-5 months since launches.
On the other applications side, skepticism stems primarily from the fact that operators have long tried to create an ecosystem of developers etc. through their own applications stores, open APIs and portals etc. Many of these initiatives like Verizon’s application store were unceremoniously shut and others died or are still languishing doing little justice to the fanfare with which they were launched just a couple of years ago.
The same problems that led to the demise of operators applications stores and alike will ail open API, in-house, outsourced or partnership driven application initiatives on IMS and this will be a passé discussion few years hence.

Fixed / Mobile Convergence
Based on what Rogers has achieved through Rogers One Numbers and China Mobile has achieved through 3G life-G3 communications- one can safely claim that fixed/ mobile convergence use cases based on IMS have a strong case for consumer preference. One number across your PC and mobile through which you can switch your calls from phone to PC. Conferencing, chatting, call routing to all devices on a number, voice and video chat, have all seen initial and significant success, and it is a very good tool for an operator to differentiate themselves from others. Besides, it helps an operator to realize strategic benefits from IT investments across multiple IMS implementations at the back end. Several operators that offer both fixed and mobile services will leverage this synergy to bundle and price their offerings in a way to maximize their revenues and gain an edge over the competition.

Bottom line, in 2-3 years VoLTE will start to become mainstream, Joyn and RCS and any application related initiatives by operators will not succeed and the fixed-line operator will have another weapon up their sleeve to go out and differentiate themselves from the competition.