Given their investment in, and roll out of LTE it makes economic sense for both AT&T and Verizon to start to focus on LTE as a delivery network for voice serves. With early 2014 launches on the cards, it seems like we’re moving to a stage where, over time, running voice services over circuit-switch networks and a data service over a separate IMS (IP Multimedia Subsystem) LTE network will become a thing of the past.
Operators are continually looking for ways to reduce opex and telecoms equipment vendors are promoting some pretty impressive savings enabled by running voice and data services on the same LTE network. According to one equipment vendor, these include 60% lower operations & maintenance costs, 75% lower site support costs and 65% lower energy costs. Add this to the improved spectral efficiency (twice that of 3G / HSPA, and six times GSM) then it would look like the economic arguments for VoLTE make sense.
But it’s not just a case of saving money. Korean operator and VoLTE pioneer, SK Telekom have reported that VoLTE dramatically improves audio quality (able to handle 2.2 times wider frequency bandwidth as 3G voice) and has much improved call setup times which range from 0.25 to 2.5 seconds on LTE, compared with a five second setup time on 3G. It’s worth pointing out that SK Telekom have over 4.5Million subscribers using VoLTE service, which they heavily marketed as HD voice, so it’s fair to say that when they talk about improved call quality they know what they’re talking about.
With LTE service launches seemingly happening on a weekly basis, and the number of 4G customers and devices growing by the day, VoLTE seems to be building on a very solid foundation. Research firm telecoms.com intelligence ran a poll recently that showed that the vast majority of operators would look to provide VoLTE services less than two years after their initial LTE launch. Looking at AT&T’s launch and Verizon’s plans, this figure of two years looks pretty accurate.
From a billing and BSS perspective, VoLTE will create some interesting challenges. Firstly most operators will rate VoLTE calls as voice calls (e.g. start time, end time, A number, B number, national, international bands, etc). But while VoLTE calls are effectively voice calls made on a ‘data’ network the charging and billing systems will need to zero rate data transmission, and then apply voice rating rules. Also all of a sudden QoS (quality of service) is going to come into the voice equation. An issue with VoLTE is that mobile resources associated with each VoLTE call can be unpredictable, so a policy management system needs to dynamically manage these network resources to ensure the HD service promised is what is delivered.
If operators are going to market (as several are already doing) VoLTE as high definition voice, then they need to ensure that quality is there, and is better than the OTT VoIP services. Delivering QoS is essential for VoLTE. To do this needs high performance, flexible policy management that supports VoLTE – and that is what Openet delivers.
