VoLTE
Voice over LTE
ADVANCED TOPICS IN NETWORKING
AMERICAN UNIVERSITY IN BOSNIA AND HERZEGOVINA
November 20, 2016
Authored by: Eldar Bajrovi, Emir Selmanovi, Lejla Deko, Semir Mai
Contents
HISTORY.................................................................................................................... 2
WHAT IS LTE? .............................................................................................................. 4
VOLTE .............................................................................. ERROR! BOOKMARK NOT DEFINED.
WHAT IS VOLTE?............................................................................................................. 7
WHAT IS THE MAIN DIFFERENCE BETWEEN VOIP AND VOLTE?? ...................................................... 8
HOW VOLTE WORKS? ...................................................................................................... 10
CORE NETWORK ............................................................................................................ 12
USE AND BENEFITS OF VOLTE ............................................................................................. 14
1. HIGH QUALITY VOICE ....................................................................................... 14
2. RCS (RICH COMMUNICATIONS SERVICES) ........................................................... 14
3. CALL SETUP TIME ............................................................................................ 14
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4. BATTERY LIFE ................................................................................................ 14
5. INTEGRATION ................................................................................................. 14
6. DEVICE INTEROPERABILITY ............................................................................... 15
COMPARING VOLTE TO 3G SERVICES SUCH AS SKYPE ................................................................. 17
CONCLUSION ............................................................................................................. 17
BIBLIOGRAPHY ............................................................................................................ 18
VoLTE
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VoLTE
Voice over LTE
Introduction
HISTORY
Interesting facts about telecommunication:
Construction of the first billion fixed telephone lines lasted for 100 years, and the
addition of 5 billion mobile users only 20 years.
In December 2008, data traffic exceeded voice traffic in mobile networks globally.
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In this year it is predicted that the number of downloaded applications will reach 17.7
billion, which is an increase of 117% compared to the 2010.
Increment penetration of mobile broadband and 10% increases the annual growth of gross
domestic product (GDP) of around 1%.
From about 5 billion mobile broadband users in 2016, about 95% will use HSPA, CDMA
and LTE networks.
Since LTE is an all IP network means traditional circuit switched calls are handled bit
differently in LTE than in older mobile systems. The solution to deliver voice over internet
protocol in LTE is IMS (IP Multimedia Subsystem). That led to using other solution, CSFB (CS
VoLTE
Fall Back). Another alternative to IMS based VoLTE was VoLTE over Generic Access proposed
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by VOLGA forum. It was also declined after some time. In the 2009, most of the large telecom
operators proposed their own solutions for IMS. Year later, Global System for Mobile
Communication (GSMA) started making official solution and they provided voice over LTE.
They were supported by 50 organizations from the whole world. In March 2010, they published
IR.92 solution, and freeze it in September. In August 2012 was the first commercial VoLTE
deployment by SK Telecom and MetroPCS.
3GPP LTE will enable cellular communications services to move forward to meet the needs for
cellular technology to 2017 and well beyond.
Many operators have not yet upgraded their basic 3G networks, and 3GPP LTE is seen as
the next logical step for many operators, who will leapfrog straight from basic 3G straight to
LTE as this will avoid providing several stages of upgrade. The use of LTE will also provide the
data capabilities that will be required for many years and until the full launch of the full 4G
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standards known as LTE Advanced. Caption 1 provides us with current data on operators that
launched VoLTE, markets they are covering, services and devices that can use VoLTE.
VoLTE
C APTION 1: C OMPARISON OF OPERATORS WHICH LAUNCHED V O LTE
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VoLTE
What is LTE?
4G stands for fourth generation of mobile data technology as defined by ITU-R
(International Telecommunication Union). 4G was expected to be a great evolution in wireless
communications. Fourth generations working group defined objects that were far more
advanced than any other previous technology. 4G was imagined to have a spectrally efficient
system, high network capacity, data rate of 100Mbit/s for access in a moving object and 1Gbit/s
for stationary object, and data rates of 100Mbit/s from any point in the World to other point. It
would have smooth handoff across heterogeneous networks, seamless connectivity and global
roaming across multiple networks. The fourth generation of cellphone telephony is only all IP,
packet-based (unlike previous generations) and it supports IPv6.
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Long term Evolution (LTE) is not a technology like 4G, but the path you need to go in
order to achieve 4G speed, and high quality of service. Shortly, it was developed by the 3rd
Generation Partnership Project (3GPP) and it allows speed of 100Mbps at least. It provides
telecom services, HDTV and large access in completely IP based environment. Same stations
used for 3G can be used for LTE too if you just adjust equipment and software a bit.
So lets see statistics a bit. We can see on Caption 2 that LTE networks are over 2500
times faster than GSM was, and that LTE is on the top of network evolution.
VoLTE
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C APTION 2: S PEED COMPARISON BETWEEN LTE, 3G, AND 2G
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LTE has MIMO (Multiple Input, Multiple Output) as the part of its standard. That means
that it is using more antennas for receiving and sending which automatically enlarges the speed
of broadcasting. It is just another thing that 3G already had, so LTE didn't have to develop it
again. Also from WiMAX they took OFDM (Orthogonal Frequency Division Multiplexing). It is
a technology for sending digital signals. Signals are divided into more parallel data channel
which are being broadcasted by different frequencies. LTE can use frequencies from 1.4MHz to
20MHz. When you put all these features together, you get blocks of data. Each customer can
receive various data block depending on their need and approach. From the base station, blocks
of data can be broadcasted to the cell phone if there is free space. And from the cell phone to the
base station all of the data blocks are being sent with neighboring frequencies in some part of
VoLTE
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time. Customers can enjoy wireless access with wide range of interactive services like web
surfing, online games, real time video conferencing, networking and exchange of multimedia.
In order to simplify and accelerate building of new LTE networks, and lowering costs,
two of the biggest trends in developing LTE are MSR (Multi Standard Radio) and SON (Self
Organizing/Optimizing Network. That will help base stations to support radio modules that can
be software modified for using different types of technologies. For example, it will allow them to
use GSM, WCDMA or LTE.
Even though LTE is imagined to be network based on packet broadcasting exclusively,
they decided to find ways of implementing voice and SMS services. Main challenge for this
industry was defining standard solution that will provide global and universal usage, and avoid
fragmentation. Top support had One Voice initiative with 3GPP standardized solutions based on
IMS services like MMtel (MultiMedia Telephony).
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VoLTE
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What is VoLTE?
LTE networks gave a business solution that
provided network operators a solution that evolved to all-
IP communications network. Most wireless providers are
using tradition circuit-switched networks that base is
evolved towards an IMS core network. This mobile
solution allows wireless operators communication
services such as are HD voice, HD video calling, IP
C APTION 3: V O LTE CALL ON A SMARTOHONE
messaging, contact manager, and Wi-Fi calling..., by transmitting voice in the same way it
transmit data. With the Evolved Packet Core, VoLTE puts voice call into packets. With this
technology, voice call is same as sending a Facebook message and it is high-quality.
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VoLTE
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What's the main difference between VoIP and VoLTE ?
First of all, VoIP is a very broadly used term, anything transfered using IP packets is
included, such as FaceTime, Viber, Skype, etc.
IP packets are still packets, which means that they are transefed on the layer 7 and go
through L1-L6, as every other packet. The packets are only recognized as voice by the
application which receives and processes them - Viber for example. This transfer is possible on
any type of network, including 3G, LTE, WiFi, ADSL, etc.
VoLTE is a very specific type of VoIP, adapted for the LTE standard - which of course
allows for many optimisations and accelerations. In a real-life example, these packets are
"special" in the whole LTE network, and are treated as such. This allows them to have lower
latency and use less power, as well as do hangovers to other LTE cell towers or 2G/3G networks.
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A very good and respected consultancy group, Signals Research Group in collaboration
with Spirent performed testings and concluded:
Commercially deployed Voice-over-LTE (VoLTE) technology provides better service than 3G
Circuit Switched (CS) voice and Internet calling services and Skype software.
The analysis found that VoLTE users enjoyed considerably better call quality, faster
connectivity and substantially less drain on the batteries of their mobile devices.
VoLTE
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C APTION 4: C OMPARISON OF V O LTE AND V O IP
VoLTE
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How VoLTE works?
Integral parts of VoLTE are LTE and packet core with its IP flow. There has to be
operability between device and the network, so they provide that. Interface requirements are
based on the 3GPP, and Access Domain Selection. Even though the LTE is not available on large
number of devices, they aim to set minimum mandatory requirements for them and network.
Caption 5 illustrates the importance of taking an end-to-end approach to implementation
of VoLTE. VoLTE interfaces across the User to Network Interface (UNI) between device and
network. It is very important to utilize end-to-end tested network-to-device functionality.
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C APTION 5: V O LTE INTERFACES
VoLTE
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We can explain how VoLTE works on Wi-Fi calling. First, Wi-Fi calling needs to be
enabled in the device and in the network too. When untrusted not 3GPP access the device, it
needs to allow new integrated functionality in the EPC, with the Evolved Packet Data Gateway
(ePDG) and connect to the IMS network. The ePDG provides many security mechanisms such as
IP sec tunneling of connections with the device over untrusted non-3GPP access that provide
safe ongoing VoLTE call to the users home Wi-Fi. The services still anchored in the operator
network via the ePDG.
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VoLTE
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Core Network
VoLTE's core network has following features:
IMS (IP Multimedia Subsystem) core network for delivering multimedia services. It
includes:
- CSCF Call session control function
Call session Control function plays the essential role in those networks. It's main
function is signaling and controlling of the user equipment through out the entire IMS
core network.
- MGC Media Gateway Controller
MGC controls most of the media servers and gateways. This controller is receiving
signalling info from the media gateway and using that information to send, recieve
and alert about sending and recieving the voice data.
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- User management infrastructure HSS home subscriber server
HSS is the main database of the IMS. It includes all the user information such as are
user identification, user addressing and profile information. It also includes the
maximum allowed bit rate of traffic, making it the core database of all subsctioption
data.
- IP works
- CUDB Centralised User Database
This database consolidated the subscriber's profile data from all active users and
devices in VoLTE network.
MTAS (Multimedia Telephony Application Server)
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Includes several application server roles and it is used to support small and enterprise
voice services. In VoLTE it provides more reliability, capacity and efficiency ion the
application level
MSS (Mobile Softswitch Solution)
- provides voice services in handover scenarios when there is no LTE coverage
- support in roaming
DSC (Diamater Signaling Controler) - support in roaming
It acts like a regulator of traffic for data messages in VoLTE networks. It goes by a
signaling protocol that enables communication between the network elements.
Sometimes you can reffer to it as a language of communication used between servers,
softwares and the core of the network itself.
Evolved Packet Core
- MME (Mobility Management Entity)
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MME provides the VoLTE with mobility session managemen. It is used for the
authentication of the users, roaming of the network and handing over the files to other
networks,
- PDN/Serving Gateway
This gateway communicates with the networks outside the primary one.
SAPC (Service Aware Policy Controller) policy control
SAPC is the centralized policy management controller that allows you to set the policies
on the user per user level. It is easily customizable and allows you to change policies,
personalize network and optimize the usage of the network resources.
VoLTE
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Use and benefits of VoLTE
1. High quality voice
Like name says, Voice over LTE, voice is the most important benefit of this technology.
Calls via VoLTE are noticeacly improved from the traditional 8kbps codec to over than
13kbps. Methods of compression are modernized so it also provides faster transmission.
2. RCS (Rich Communications Services)
With VoLTE we have whole new set of standardized services. We are all familiar with
Skype, most popular video calls service, and iPhones FaceTime. They were all functioning
before VoLTE. But besides other functions that are better in VoLTE here is important that
now you don't have to have these apps in order to voice call. You can use these services
without opening a separate application, from your phone directly.
3. Call setup time
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VoLTE provides much faster call setups and connecting calls. Up to two times faster
actually.
4. Battery life
Not only the quality is better, but is consumes less device's battery. All other VoIP
applications like Skype were using more battery, so this is really meaningfull for portable
devices.
5. Integration
VoLTE can be easily integrated with the Wi-Fi services, which is really important since a
lot of operators is using Wi-Fi to hangle voice calls, and other data traffic. Transition
between cellular voice call and Wi-Fi call is improved so the coverage is almost
VoLTE
unbreakable.
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6. Device interoperability
Main goal after VoLTE covers most of the network space is a device that can work on any
wireless network. All the operators would be delivering data services and voice services
using the same 4G LTE technology
7. Guaranteed Quality of Service
It is important to mention LTE Advanced. It is LTE 3GPP Release 10 which will provide speed
from 1000 Mbit/s in downlink and 500 Mbit/s in uploading. It will aggregate LTE Release 8 with a
channel of 20 MHz, frequency spectre, 4x4 MIMO in upload and 8x8 in download.
Devices using VoLTE
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Besides LTE USB stick modems and smart phones, large number of electronic devices
can use VoLTE too. Notebooks, ultra-portable devices, playing consoles, televisions and even
cameras can have integrated LTE. Today all Windows 8.1 devices have integrated VoLTE,
iPhone 6 and iPhone 6 plus, and a lot of new Samsun, Sony, and LG devices too. And in last two
years, more than a hundred of operators are either planning or already have LTE covered.
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Comparing VoLTE to 3G services such as Skype
Alcatel-Lucent, that is currently keeping
the lead in producing equipment for IMS, did an
interesting independent study where they
compared this new VoLTE networks calling and
Skype calling. It was obvious that VoLTE enables
4G to deliver not only faster, but all IP C APTION 1
communication which in perfect conditions proves how more secure, and faster than 3G it is.
When comes to Skype, it slows down if were using some other application along with him, and
latency can be horrible. We are all used on HD now, and in this report they proved that
customers wont be disappointed with VoLTE. Nothing was the same for them, once they tried
HD voice call. The call setup of VoLTE was twice faster than the Skypes. And the best thing
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was when they disconnected 4G coverage, VoLTE successfully switched to 3G without stopping
the call.
VoLTE
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CONCLUSION
To make a conclusion, let's present some downsides first. VoLTE is still a new and
growing technology. It is normal that there will be dropped calls and that it won't be perfect from
the start. Both, the caller and receiver of the call have to have LTE, and the signal must be
strong. Another downside is that VoLTE is still limited to certain devices, but devices of future
all have VolTE. And finally, we have pricing. We all know that you are paying for how much
you consume. VoLTE is based on sending and receiving packets, so it probably takes a lot of
Mbps from your pocket. And devices that have VoLTE today are expensive too. In the long run
it is worth waiting.
When VoLTE manages to make interoperability, and operators get more experience,
customers will benefit. Losing connection and dropped calls will be resolved first, and the final
step is to provide every device with VoLTE.
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The clear choice for mobile network operators should be a no brainer, VoLTE delivers a
consistently higher call quality than OTT voice applications. Operators should also strongly
consider the long-term network savings associated with VoLTE, given that it takes advantage of
advanced features that allow it to use far less network resources when it comes to supporting a
voice call when compared with current OTT voice applications.
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BIBLIOGRAPHY
@3glteinfo. "VoLTE History and Timeline - Voice Over LTE Tutorial." 3GLTEInfo.
3GLTEInfo, n.d. Web. 17 Nov. 2016. <http://www.3glteinfo.com/volte-history-
timeline/>.
@droid_life. "Verizon VoLTE Launch Details: Advanced Calling 1.0, Devices, Video
Call Billing, and More | Droid Life." Droid Life. N.p., 27 Aug. 2014. Web. 17 Nov. 2016.
<http://www.droid-life.com/2014/08/26/verizon-volte-launch-details-hd-voice/>.
Louvros, Spiros, and Angelina Gkioni. "Voice Over LTE (VoLTE): Service
Implementation and Cell Planning Perspective." System-Level Design Methodologies for
Telecommunication (2013): 43-62. Web.
"Mobile Telephony Evolution with VoLTE." Ericsson.com. Ericsson, n.d. Web. 17 Nov.
2016. <http://www.ericsson.com/us/ourportfolio/telecom-operators/mobile-telephony-
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evolution-with-volte>.
"Our History in Depth Company Google." Our History in Depth Company
Google. Google Inc., n.d. Web. 14 Nov. 2016.
<https://www.google.com/about/company/history/>.
Poikselka , Miikka, Harri Holma, Jukka Hongisto, Juha Kallio, and Antti Toskala.
Voice over LTE (VoLTE). Chichester, West Sussex, United Kingdom: John Wiley &
Sons, 2012. Print.
ReardonC, Marguerite. "6 Reasons Why You'll Eventually Want Voice over LTE."
CNET. Cnet.com, 30 Aug. 2014. Web. 20 Nov. 2016. <http://www.cnet.com/news/6-
VoLTE
reasons-why-youll-eventually-want-voice-over-lte/>.
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"Signals Research Group Study Shows Commercially Deployed Volte Service Better 3g
and Internet." Alcatel Lucent. Alcatel Lucent, n.d. Web. 17 Nov. 2016.
<http://www.alcatel-lucent.com/press/2014/signals-research-group-study-shows-
commercially-deployed-volte-service-better-3g-and-internet>.
"VoLTE Demoed in Virtualized Core-network Environment." Ericsson.com. Ericsson, 18
July 2013. Web. 17 Nov. 2016. <https://www.ericsson.com/news/130718-volte-demoed-
in-virtualized-core-network-environment_244129227_c>.
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VoLTE
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