ITU Workshop on “Voice and Video over LTE”
Geneva, Switzerland, 1 December 2015
KT VoLTE status and commercial interconnected
VoLTE service in South Korea
June Young Jeon
Principal Research Engineer
juneyoung.jeon@kt.com
Contents
1. KT’s Business and Korean Market
2. Commercial Interconnected VoLTE Service
In
3. Achievements & Issues
4. Conclusion
KT: Corporate Profile
• Subsidiaries
Established
December 10, 1981
Revenue
USD 23.4 Billion(2014)
Stock Listing
Korea, New York, London
No. of Employees
23,754(as of Sep. 2014)
- Communications, IT Services,
Media & Contents, Capital, Security
• Overseas subsidiaries and offices
- 7 Subsidiaries(USA, China, Japan, etc.)
- 10 Offices
In
Fixed Phone
Broadband
Mobile
Pay-TV
17.3M (58.6%)
8.1M (42.4%)
17.2M (30.3%)
7.0M (25.1%)
Global Telecommunications Infrastructure Comparison
▣ The world’s highest level of broadband penetration rate
▣ Outstanding LTE connection and wireless penetration rate
Broadband Penetration rate
Time on LTE
91%
88%
97.2
In
Korea
68.2
67.3
66.7
U.S.
EU 27
OECD
Average
 Source: OECD Internet Economy Outlook 2013
Wireless Penetration rate
123.3%
68%
101.8%
67%
100.7%
72.4%
Korea
Sweden
Japan
U.S.
 Measures portion of time connected to LTE
 Source: Open Signal, 2014
Finland
Korea
 Source: OECD (2013)
U.S.
OECD
Korean Market and KT’s market share
▣ Wireline and wireless markets saturated, while Pay TV market is growing
▣ KT is leading wireline and Pay TV market, and is second in wireless market
KT‘s Market Share (as of Feb 2015)
Telecom Market Size Trend
Growth rate of Wireless (2%) and Wireline (2%)
implies market saturation
Pay TV growing most rapidly: 19%


60
(Unit: mil.)
50
40
30
20
10
0
Wireless
Dec. 2012
Wireline
Dec. 20132
Pay TV
Dec.2014
In
 Wireline: 42% (1st)
 Wireless: 30.4% (2nd)
 Pay TV: 28.6% (1st)
100%
90%
80%
70%
60%
50%
40%
30%
43.1%
20%
30.4%
10%
0%
Wireless
Wireline
KT
SKT
LG
28.6%
Pay TV
Others
Contents
1. KT’s Business and Korean Market
2. Commercial Interconnected VoLTE Service
In
3. Achievements & Issues
4. Conclusion
World’s 1st commercial Interconnected VoLTE Service
▣ Commercial Rollout (Jun. 2015)
South Korea’s mobile network operators announced the commercial
interconnected VoLTE service
In
GSMA Awards Certificate of Special Recognition for Launch of World’s
First Commercial Interconnected VoLTE Service in South Korea
Legacy Interworking Architecture
SKT Network
KT Network
Legacy
Circuit
PCRF
UE-A
E-UTRAN
SGW
MGW
IMS
UE-B
EPC/
E-UTRAN
TAS
HSS
MME
MGCF
PGW
CSCF
BGCF
MGCF
In
LGUplus Network
MGW
Legacy
Circuit
MGCF
MGW
Control
Plane(SIP)
IMS
UE-C
EPC/
E-UTRAN
User Plane(RTP
media)
Dedicated Working Group
▣ TTA-WG9102 : VoLTE interworking specification between Korean MNOs
ㆍMembers
- TTA(Telecommunications Technology Association), KT, SKT, LG Uplus
ㆍPeriod
- 2012.10 ~ 2013.10
ㆍPurpose: to complete core protocols and transmission specifications
-
call flow (ex, video announcement, ring back
In tone, early-session)
SIP header, Reason header, SDP parameter, SIP numbering plan
codec, response code, session timer
device capability of voice-video switching
IBCF requirements for interworking
* TTA-WG9101: Specification of VoLTE Terminal for UICC Portability between Mobile Operators
* TTA-WG9103: Rich Communication Suite(RCS) Interworking Specification for Mobile Network Operator
Evolution of Interworking Architecture
Other Networks
KT Network
TAS
HSS
UE-A
E-UTRAN
MME
PCRF
SGW
PGW
CSCF
BGCF
MGCF
MGW
Legacy
Circuit
HSS
E-UTRAN
MGW
IMS
UE-B
EPC/
E-UTRAN
Other Networks
KT Network
UE-A
MGCF
MME
PCRF
SGW
PGW
TAS
ENUM
CSCF
IBCF
IBCF
TrGW
TrGW
Control
Plane(SIP)
IMS
UE-B
EPC/
E-UTRAN
User Plane(RTP
media)
Practical Implementation
▣ Standard : IR.65 6.3.3 Interworking
Routing of SIP signalling over the IMS NNI requires use of SIP URIs.
• Session requests based upon E.164 format Public User Identities require conversion
into an NNI routable SIP URI format.
▣ Implementation in Korea : Routing in TEL URI format
KT Network
Other Networks
kt
ENUM
NPDB
①
CSCF
Query : B
 Routing Number
IBCF
②
INVITE in TEL URI Format
other
ENUM
③
Query : B
 SIP URI
MGCF
IBCF
CSCF
Contents
1. KT’s Business and Korean Market
2. Commercial Interconnected VoLTE Service
In
3. Achievements & Issues
4. Conclusion
Process of Service Interconnection
Interworking Test
‘15.05
‘15.07
▣ Milestones
Trial Service
6th stage
12th stage
18th stage
3.8 million
20 million
55 million
Commercialization
‘15.08
In
`15.05~`15.07
- User device / network / charging test in commercial network
`15.07~`15.07
- Trial service(50 subscribers for each operator)
`15.08~`15.10
- Migration of 55 million subscribers on a stage-by-stage basis
‘15.10
Achievements
▣ Switching Interconnection Traffic – Circuit to Packet
90
(
)
57
MGCF
IBCF
Aug. 4th
Sep. 17th
Oct. 29th
In
▣ Enriching customer experience
- Seamless switch between voice and video, faster connection speeds
Media Type
VoLTE
3G
Voice
Wideband (HD Voice)
Narrowband
Video
VGA (480 X 640)
QCIF (176 X 144)
Interworking Issues in Commercialization Stage
▣ End-to-End codec negotiation and media connection issues
- Operator specific UE Spec
RTP
- RTP timeout
SDP
(6%)
SIP header
(15%)
Media
(18%)
RTP
(35%)
Media
In
- one-way call
SIP Header
- Header matching error
SDP
- Parameter processing error
Contents
1. KT’s Business and Korean Market
2. Commercial Interconnected VoLTE Service
In
3. Achievements & Issues
4. Conclusion
Conclusion
▣ Summary
- Forming a dedicated working group in 2012
- Rolling out the commercial interconnected VoLTE service in 2015
- Providing HD-Voice and Video interconnection service
In
▣ Considerations
- Transcoding overhead for existing operator-specific terminal
- Further discussion on UNI specifications in detail
- Global E-NUM for international interworking