Top quality mobile voice

Now is the time for resellers to be at the forefront of a high quality mobile voice empowered workforce, according to Gamma Product Director for Mobile Steven Lowe.

Here, he debunks the myths surrounding mobile voice and explains how key services on offer meet the requirements of a changed mobile network and a transformed channel and business landscape.

Lowe wears his passion for all things mobile on his sleeve and as the market conditions prove ever more propitious he has turned up the volume on Gamma’s latest campaign to educate resellers about the mobile opportunities on their doorstep. This comes as Gamma gives the megaphone to its Voice over LTE (VoLTE) service which is available across the whole of the 3UK 4G network and, claims Lowe, has the potential to transform how businesses communicate.

“The service is available over the 800MHz spectrum which offers broader and deeper coverage,” explained Lowe. “And the impending 3G switch off means that mobile customers must use VoLTE (voice over 4G) if they are to continue with native voice services. Furthermore, the planned PSTN switch off also means that customers will need to act if they want to retain voice services, either by switching to broadband with a voice application or by replacing PSTN with mobile.

“These major industry shifts provide a significant opportunity for the promotion of high quality voice services and a reason to engage positively with business customers. There are approximately 10.8 million business smartphone users in the UK, so there is a huge addressable market for the channel to engage with.”

Mobile networks around the world are starting to decommission their 3G networks. AT&T in the US is expected to close down 3G at the end of February 2022 and UK networks will start to decommission 3G in the latter part of 2023. “It is essential therefore that mobile operators, MVNOs, resellers and dealers start to work with customers as soon as possible to ensure that they have access to VoLTE compatible devices,” added Lowe.
His enthusiasm for his subject yields much food for thought for resellers, particular as he dismantles misconceptions about mobile voice. “We want to bust the myths surrounding mobile voice quality,” he added. “It is extremely high, especially over LTE and using the EVS codec. This is absolutely appropriate as a service for business customers.”

The EVS codec includes a multi-rate audio codec, a source controlled variable bit-rate (SC-VBR) scheme, a VAD, a comfort noise generation (CNG) system, and an error concealment (EC) mechanism to offset the effects of transmission errors resulting in lost packets. Its channel-aware mode feature further improves frame/packet error resilience. EVS codec for 4G voice calls is also adaptive, so that if poor signal quality is detected then it will adjust to a lower quality in order to preserve the call.

There are approximately 10.8 million business smartphone users in the UK, so there is a huge addressable market

It is clearly not the case that mobile voice quality is lower than landline voice quality. “Quite the opposite in fact,” stated Lowe. “Mobile voice quality always matches or exceeds landline voice quality. On a mobile to landline or landline to mobile call, landline codecs actually constrain mobile voice quality. In order for the call to work, the call falls to the lowest common denominator - the PSTN codec, G711, has been in operation since 1972.”

So we can see that mobile voice quality has historically been constrained by having to conform to minimum landline specifications, and that VoLTE with the EVS codec is of a substantially higher quality than fixed line PSTN voice. The positive difference in favour of VoLTE lies in the fact that while the G711 PSTN codec offers bandwidth between 300Hz and 3.4KHz, VoLTE with EVS offers bandwidth at up to 20KHz along with a number of advanced features, offering high definition voice of the highest quality.

“All UK MNOs now offer VoLTE and if the EVS codec is applied this delivers an extremely high-quality voice experience,” emphasised Lowe. “The main requirement is for increased coverage, rather than quality, and while all UK networks promise in excess of 98 per cent indoor coverage, this is calculated on the basis of the building being a standard residential building, rather than an office complex which may, due to the layout and construction materials used, inadvertently block external radio signals.

“For businesses with fixed broadband, Ethernet, FTTP or SD-WAN, native WiFi calling via mobile can be an elegant and free in-building coverage solution. The solution is seamless where it supports SMS and voice with two-way seamless handover to the mobile network. If in-building coverage is an issue and there is no fixed connection, other solutions are available, from Repeater solutions which bring external coverage into the building and amplify it, to Fixed Wireless Access where a business runs all its communications over 4G/5G via an external antenna, through to private networks where spectrum is procured to meet local coverage needs.”


Gamma has spent the past two years building its new Gamma Mobile platform with 3UK, and Lowe forecasts that in three to five years time Gamma Mobile will be the most successful UK B2B MVNO operating across all UK business segments. “We will do this by maintaining our laser focus on the business market, understanding and delivering end-to-end solutions to meet end customer and channel partner needs, and leveraging the network advantages that we will have across 4G and particularly 5G,” he stated.

The quality of the network signal is another traditional limiting factor, caused by the distance from the cell tower as well as other environmental variables. “It is important to remember that 4G has roughly double the spectral efficiency of 3G, therefore able to provide better quality voice for the same signal quality,” pointed out Lowe. “The new EVS codec for 4G voice calls is also adaptive, so that if poor signal quality is detected then it will adjust to a lower quality in order to preserve the call.”

Because the quality of any network service experience can be impacted by the characteristics of the device being used, whether over fixed or mobile, it is important to be confident that the devices sold to customers perform well with the service, including voice. To gain access to 4G voice, customers require a VoLTE compatible device. The vast majority of modern devices are VoLTE compatible but there remains a small percentage of non-VoLTE compatible devices in use with business users. “We test devices across the various price ranges for performance on the network and across various applications,” noted Lowe. “The resulting list of recommended devices is made available to all of our mobile channel partners for information and guidance.”

Gamma has a strong relationship with 3UK with equal access to the network. This means that as new network technologies are developed Gamma and its customers have immediate access. “While 3UK provides the network that is at the heart of our mobile service, Gamma also has its own network, provisioning, channel and customer support capabilities that enable us to offer an end-to-end proposition laser focused on the business market,” added Lowe.

“High quality voice is an important component of our mobile service going forward. This operates over 4G today, but voice over 5G will be available in the future. But right now, the impending 3G network shutdown will be a big catalyst for the sale of VoLTE and associated high quality mobile voice. And the PSTN switch off will be another accelerator.”


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