ROCCO researched the situation with VoLTE and HD Voice in the US Market and wanted to share two articles which give a great overview.
The good news about voice-over-LTE (VoLTE) is that it works as advertised, crisp, high-quality sound with an instant connection, but the bad news is a lot of stars have to align to actually experience it.
Independent testing consultancy P3 Communications has completed what it says is the first independent mobile benchmark of VoLTE service in the US via two weeks of intensive testing in April and May spanning 1,300 miles of Washington D.C.
Carriers’ own tests have shown strong VoLTE performance, but this is the first to compare the big three operators that have it deployed thus far. Verizon Wireless and T-Mobile US Inc. have nationwide coverage, while AT&T Inc. is still in the midst of deploying it market-by-market. Sprint Corp. does not yet have VoLTE rolled out, but was included in the study for its legacy voice calling, which fared quite well given that it uses the high-definition codec.
P3 measured quality, speed and reliability on Samsung Galaxy S5s and found that the quality was significantly improved over legacy voice, especially on AT&T and Verizon, which did not have HD voice on their circuit-switched networks. Average call set-up times also improved to between five and 15 seconds.
Dropped calls were also rare, and P3 CEO Dirk Bernhardt said the engineers only handed off (seamlessly) to a legacy network six times out of a total of more than 2,000 calls made, five on AT&T, which fell back to 3G, and once on T-Mobile, which, interestingly, fell back to its 2G network even though it had 3G CDMA deployed in DC. Verizon does not offer handoff to CDMA as it can’t support eSRVCC. Bernhardt said a few calls were dropped, but overall reliability was “surprisingly good.”
“VoLTE is ready for prime time,”
“I tell everyone to try it out. You’ll be surprised in the beginning at how different the voice quality is.”
Bernhardt thinks it’s time for the operators to be more aggressive with deploying it and marketing it to their customers. The problem is, however, while the service does work well, there are still a lot of caveats with VoLTE as it is today in the US.
The biggest issue is that VoLTE calls will only work within a single carrier network, and even then, only if both parties have to have VoLTE-capable phones and have it turned on for voice calling. They then also have to be in an area with good LTE coverage.
If all those conditions are met, they can enjoy the crystal-clear calling. Otherwise, it’s plain old legacy voice for them. Also, as we discovered on my interview with Bernhardt, three-way calls fall back to legacy when the third party is added.
What is VoLTE?
Today, Verizon and other wireless providers transmit voice calls over the traditional circuit-switched networks, and subscribers use the newer IP-based 4G LTE network to access the Internet and other “data” services. The VoLTE, service enables wireless operators to use the data network to transmit voice services in the same way they transmit data. In short, it chops up voice calls into packets, just as emails, Facebook messages, and all other communications over the Internet are “packetized.”
By turning voice into IP packets, the companies are able to offer high-quality voice calls, as well as services that look more like what so-called “over-the-top” Internet app developers have offered over the open Internet.
Consumer VoLTE benefits
1. High-definition voice: The most noticeable benefit consumers will experience with VoLTE is improved voice quality. Traditional voice networks transmit voice calls using an 8kbps codec. Verizon says it’s using a 13kbps codec that also uses more-modern compression methods. The result is a call that’s noticeably clearer than a typical cell phone call. I tried it out for myself on Verizon’s LTE network during a press briefing. I was skeptical that I’d notice the difference, but when I switched between the two networks using an LG G2 smartphone, I definitely noticed. And the VoLTE call was superior.
“The difference between a voice call made over VoLTE and one using the traditional CDMA network is like the difference between talking through a tin can connected with string and a full symphony in CD quality,” said Roger Entner, lead analyst at Recon Analytics. “It’s night and day.”
2. Rich Communications Services or RCS: VoLTE also will enable wireless operators to deliver a new set of standards-based services referred to as Rich Communications Services, or RCS. These services include things like video calling, file transferring, real time language translation, video voicemail and instant messaging. Many of these applications are already delivered over cellular data service using third-party apps. For instance, iPhone users are very familiar with FaceTime for video calling. Millions of people use Skype for video calls as well as messenger services. And Google offers its Google Translate service.The benefit of VoLTE is that it lets you launch these services directly from the phone’s native dialer. As Greg Dial, executive director of mobile services for Verizon, explained it to me recently,
“There’s no opening a separate app.”
Right now Verizon Wireless is the only carrier offering video chat as part of its VoLTE service. And no one is yet offering any of the other more-advanced features. But eventually Verizon and other carriers deploying VoLTE will add other Rich Communication Services.
Another thing to keep in mind is that there are services that could be enabled by VoLTE that no one has even thought of yet.
3. Faster call setup times: Connecting calls using VoLTE will be much faster than it is today using the older circuit-switched technology on a 2G wireless network. How much faster? T-Mobile CTO Neville Ray has said it can be up to twice as fast as non-VoLTE call setups.
4. Improved battery life over other VoIP apps: A report released earlier this month from Signals Research Group suggests that VoLTE services offer much-improved battery life compared with using an over-the-top Voice over IP service such as Skype.
“VoLTE delivered a consistently higher call quality than circuit-switched voice and over-the-top applications,”
Michael Thelander, CEO and founder of Signals Research, said in a statement. “In addition, VoLTE really shined when it came to its network requirements, consuming far less than a Skype voice call, which translates into a meaningfully longer smartphone battery life.
5. Integration of VoLTE with voice over Wi-Fi service: Another benefit for consumers is better integration between a wireless operators’ cellular voice service and a Wi-Fi calling service. This is particularly important for operators, such as T-Mobile and Sprint, which are starting to use Wi-Fi to handle some voice calls, as well as other data traffic. Improving the transition between the cellular voice call, which uses licensed wireless spectrum, and a Wi-Fi call, which uses unlicensed spectrum, is important because it could let these operators get better indoor coverage in areas where their licensed wireless spectrum is limited. That means improved coverage for consumers.
Because the call setup necessary for voice over Wi-Fi is the same as the setup for VoLTE, once VoLTE is fully deployed, it will be easier and more seamless to offer voice over Wi-Fi in areas where licensed spectrum is either weak or unavailable.
6. True device interoperability: Once carriers make VoLTE services interoperable among different carrier networks, there won’t be any technology barriers among most of the world’s wireless operators. The CDMA/GSM divide that’s separated the four major wireless operators in the US will no longer be an issue. What this could mean for the average consumer is that you may be able to buy one device that could truly operate on any wireless network. All the major carriers would be delivering data services and voice services using the same 4G LTE technology. And if your smartphone supported enough LTE wireless bands, you’d be able to take that device to any carrier and get both voice and data service.
The downsides to VoLTE
1. More dropped calls…at least initially: Voice over LTE is a new technology. And because it’s new, it’s likely that, at least initially, it won’t work perfectly everywhere all the time.
“There can be cases, like in your home, where the VoLTE experience may not quite be the same as you were getting with CDMA,” Mike Haberman, vice president for the network for Verizon Wireless, said in an interview. “VoLTE uses different antennas. It’s a totally different technology.”
The biggest reason why the service may drop calls is because it requires that both the caller and the person receiving the call be within LTE network coverage. This is particularly true of Verizon’s VoLTE deployment, which doesn’t transition calls from LTE to its older CDMA network. What this means is that if one person on the VoLTE call leaves LTE coverage, or the LTE signal is too weak, the call will be dropped. This could result in more dropped calls for certain users.
2. Limited to certain devices: In order to make or receive VoLTE calls, both devices must include 4G LTE radios and be equipped with software that will allow the VoLTE function. On T-Mobile, the company is already supporting VoLTE on the LG G Flex as well as the Samsung Galaxy Light, the Galaxy S5 and the Galaxy Note 3. It will continue to offer the software update for other existing devices.
The first device to get the VoLTE software on AT&T was the Samsung Galaxy S4 Mini. Verizon hasn’t said which devices will initially support the VoLTE service.
In the future, most new smartphones will come with VoLTE included. There are rumors that the upcoming iPhone 6 will also support VoLTE for each of the carriers that carry it.
3. No carrier interoperability: Even though three of the major wireless carriers are offering VoLTE in at least some parts of their networks, the service will work only within a single carrier’s network for now. In other words, there’s no intercarrier interoperability among the VoLTE implementations being used. This means that someone on AT&T’s VoLTE service using an AT&T device that supports VoLTE will not be able to make a VoLTE voice call to a Verizon subscriber, who also has a VoLTE capable device, and vice versa.
Even though interoperability doesn’t exist today, it’s coming. The same was true of other services, like SMS text messaging. Initially, this service was confined to customers on the same carrier network. But eventually it expanded, and people on all carrier networks were able to text each other. The same will happen with VoLTE. The question is more a matter of when that interoperability will be nailed down and made available to consumers.
4. Pricing changes: Just when wireless operators started offering unlimited voice calls, the technology changes. Now voice calls travel over the same data network as any other data application. This could change how operators charge for basic voice service as well as other enhanced services.
In Verizon’s case, the company is currently treating voice the same on VoLTE as it did over its CDMA network. This means that if a customer had a plan where monthly minutes are counted, the minutes of a VoLTE call would also be counted. Subscribers on Verizon’s shared More Everything plans, who get unlimited voice calls, will continue to get unlimited voice calls when making those calls over a VoLTE connection.
Where things start to get a little tricky with Verizon is the video chat service. For customers using this service, the voice portion of the call will be treated as a regular VoLTE voice call, meaning voice minutes are counted for subscribers on plans where voice minutes are counted monthly. And the voice portion of the call is unlimited for customers on a More Everything plan.
But the video portion of the call will actually be counted against a customers’ allotted data for the month. Verizon estimates the video portion of a call will consume about 6Mbps to 8Mbps of data per minute. This means a 10 minute video call will eat up about 60MB to 80Mb of data. Verizon offers a data calculator so you can see how this compares with other kinds of data use. And it helps customers estimate how much data they need in a given month.
The bottom line
VoLTE is the future of voice communications on all wireless networks, whether wireless customers want it or not. There will be benefits to consumers in the long run. But in the short term, there could also be some hiccups that frustrate consumers.
Once wireless operators get more experience in real-world deployments, they’ll refine the technology. Dropped calls won’t be an issue, and eventually VoLTE and all the nifty benefits and services that come with it will be available on all wireless networks, including crystal-clear voice quality and video chat services.
Source: Light Reading, CNET