VoLTE; The challenges, the opportunities, and the future

June 9, 2020

VoLTE or Voice over LTE is a digital packet voice service delivered over IP via an LTE access network. In its infancy, VoLTE was recognized as the progression of voice services across mobile networks, delivering a superior voice experience and unlocking potential new revenue streams while still utilizing IMS as the common service platform. VoLTE also eliminates the need to have voice services on one network and data on another, making it a more efficient use of network resources and allowing operators to free up spectrum and leave their legacy domains behind.  

It comes as no surprise, therefore, that today, VoLTE plays a significant role in the telecoms market. As of the end of 2019, it was estimated that VoLTE comprised 2.1 billion users worldwide, with 272 operators investing in VoLTE over 119 countries. These numbers are projected to grow to 5 billion by the end of 2023 and according to some sources, 6.4 billion by the end of 2025, making it the most prevalent voice technology of the future.

There is also a strong focus on the development of VoWiFi as part of the mobile operator’s offering as an inexpensive way for them to solve indoor coverage problems and provide a better overall service where perhaps a mobile network would not be able to reach. VoWiFi has the added advantage of taking traffic off the mobile network and therefore expanding an operator’s overall capacity.

Perhaps most crucially, VoLTE is seen as an essential steppingstone to delivering voice services on 5G. We already see the emergence of commercially available VoLTE devices that support 5G services. Through this blog, we will address both the challenges and the opportunities VoLTE offers to the telecoms market as we progress towards 5G. 

Challenges for VoLTE

VoLTE, although mature, is not without its challenges. The essential offering of any operator is voice calls. This is still the case today despite the plethora of applications available to us. If a customer cannot place a call, they will almost certainly complain, which could lead to churn.

Therefore, operators need to ensure they are keeping a close eye on some of the potential challenges in VoLTE. One such example could be poor voice quality. This happens when there is packet loss and jitter. It is essential, therefore, to monitor the RTP as well as the average, minimum, and maximum PMOS. This will help the operator to identify which element or leg of the call caused the problem and troubleshoot as required.

One way calls or mute calls are also an issue for operators. This means that there are no packets flowing in one direction, and there is a loss of voice for a period of time. Detecting these types of calls requires the operator to identify when packets are not flowing from both sides of the call. This may indicate that one side of the call is muted. Operators can highlight this by correlating the UL and DL RTP streams and analyzing the duration of the minimum PMOS. 

Signaling overload is another potential challenge. This happens when SIP messages bounce back and forth across the network or using short SIP session time-out. The operator will again need to identify the problematic entity and drill-down to fix the problem.

Operators must also assure a call during handoffs, such as switching from VoLTE to VoWiFi, or switches between different cell towers or even between technologies. Operators must have a complete view of the network and be able to anticipate when handovers may occur, proactively optimizing those areas of the network and ensure a smooth handover.

Areas of opportunity for VoLTE

Despite these challenges, VoLTE is widely agreed to be the “Future of Voice.” Perhaps one of its most important areas of opportunity and development will be the pivotal role it will play for operators in their transition to 5G. This is because 5G will continue to utilize the 4G voice architecture and IMS to deliver voice services. As 5G progresses voice services will first be known as VoNR (Voice over Network Radio).

From VoLTE to Vo5G

Even prior to this, one significant opportunity VoLTE offers is enhanced services. When there is an all-IP based network for voice, the service quality is improved, and operators are able to deliver a broader range of Rich Communication Services (RCS). Examples of these include video calls, messaging and chat features, and the inclusion of smart devices such as watches, tablets, speakers, and many more besides. A new study by Juniper Research forecasts that over 220 million smart speakers will be used to make calls to landlines or mobile phone numbers by 2024, opening up a new enterprise revenue stream to the operators.

This is just one example of how an operator could combine with a business or enterprise to offer collaborative voice experience. Others include enabling voice and video calls from a smartwatch or enabling voice over IoT devices for an improved communication experience. OTT apps have been able to offer a sophisticated suite of offerings such as location settings, social media, video, and messaging to the user which has taken them away from the traditional voice and messaging services offered by the operator.  Having the improved call service which VoLTE offers may also go some way to helping operators claw back some of the revenues lost to OTT applications.

VoLTE also has a faster call establishment time. Previously in 2G and 3G, this could range from 3.5 – 5 seconds, but in LTE, the call establishment time is cut to just 1.5 seconds. Aside from the obvious, the benefit of this is that the operator is then able to offer supplementary services more quickly to the customer. 

All of these opportunities signify potential areas for revenue growth or a way for operators to forge loyalty among their customers.

Why Service Assurance is essential for VoLTE

If operators want to deliver on the improved voice quality that LTE offers, they cannot do this alone. Degradations can occur at any point of the network at any time, so an operator needs an intelligent end-to-end monitoring system to provide the all-important full network visibility, which proactively highlights when degradations occur across the entire network.

An operator who has a complete view of the network will also be able to pinpoint which areas require more bandwidth. If there is a heavy concentration of traffic on one cell, a smart service assurance solution will detect this and trigger an alarm alerting the operator to consider optimizing the network, catching the issue before it becomes a problem.

Additionally, a cloud-native service assurance solution will be able to continue supporting the operator as they transition from VoLTE to Vo5G with complete continuity. Such a solution delivers on-demand troubleshooting and real-time insights which will be essential in isolating issues in Vo5G.

If operators want to deliver the highest QoE to their customers, they must ensure that their VoLTE services are running smoothly. In a cloud-native environment, the only way to truly ensure this is with an intelligent service assurance solution that delivers end-to-end network visibility.

RADCOM has over 30 years’ experience in the telecoms market, RADCOM Service Assurance delivers full network visibility from the RAN to the Core, supporting VoLTE services across 4G and 5G networks. To learn more about RADCOM’s VoLTE assurance offering click here. 

This blog post may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. To read more about forward-looking statements please click here.

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