1. LTE Network and Radio Planning Design
Ali Al Sarraf
Ali Al Sarraf
1
Htc.alsarraf@gmail.com
2. •
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LTE Introduction and Architecture Overview.
The LTE Radio Interface and Channels.
LTE Link Budgets.
Capacity Planning Principles.
CPE Testing Procedure.
Ali Al Sarraf
Course Outline
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8. •
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High peak user data rates.
High average data throughput rates.
Low latency.
Guaranteed radio coverage.
Individual quality of service (QoS).
Service continuity between access networks.
Single sign-on to all network access.
Competitive prices, flat-rate fees.
Ali Al Sarraf
Typical Enablers for Next Generation Services
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9. • The next child in a long generation of 3GPP standards
LTE
“Long Term Evolution”
GSM
WCDMA
GPRS
HSDPA
EDGE
HSUPA
E-EDGE
HSPA+
LTE
4G
LTE Advanced
Ali Al Sarraf
What is LTE ?
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10. What Is 3GPP:
Ali Al Sarraf
• The 3rd Generation partnership project ( 3GPP) is a collaboration that was
established in December 1998. The collaboration agreement brings together
a number of telecommunications standards bodies which are known as
“Organizational partners”. The current Organizational partners from Asia,
Europe, and North America.
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11. • To produce technical specifications and technical reports for a 3G Mobile
system based on evolved GSM core networks and radio access technologies
that they support.
• The scope was amended to include the maintenance and development of
the global system for mobile communication (GSM) technical specifications
and technical reports including evolved radio access technologies (e.g.
General Packet Radio Service (GPRS) and Enhanced Rates for Evolution
(EDGE)).
Ali Al Sarraf
3GPP Scope
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12. • Release 99: defined the original UMTS system, supporting circuit voice
services as well as theoretical peak date rates of up to 2 Mbps.
• Release 4: defined a bearer-independent circuit-switched architecture,
separating switched into gateways and controllers.
• Release 5: defined High Speed Downlink Packet Access (HSDPA), which
boosted packet data rates to 14 Mbps on the downlink. Release 5 also
completed the design of IMS.
• Release 6: Increased data rated to more than 5 Mbps on the uplink with
High Speed Packet Access (HSUPA) and introduced support for multimedia
broadcast/multicast services (MBMS).
• Release 7: provided further enhancement to HSDPA and HSUPA, called
HSPA+, support for higher-order modulation and ( MIMO) antenna systems
offers a significant increase in data rates, potentially up to 42 Mbps.
• Release 8: defined the long term Evolution (LTE) systems, starting the
transition to 4G technology.
Ali Al Sarraf
3GPP Releases
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13. • The global system of mobile communication (GSM) is the most popular 2G standard
for mobile communication. It is estimated that over 80% of the global market uses
GSM. Standardized in two phases in 1992-1995, GSM initially supported circuitswitched voice services, circuit-switched data at 2.4,4.8 and 9.6 Kbps, and introduced
Short Message Service (SMS).
• GSM release 96 introduced higher speed circuit-switched data rates.
• The 2G GSM network uses a 200 KHz air interface, and a Circuit Switched (CS) domain
for digital voice/signaling . The CS domain consists of one or more Mobile Switching
Centers (MSC) and Telephone Network (PSTN).
• The Home Location Register (HLR) contains the subscriber records, including
authentication information and services associated with a subscriber.
Ali Al Sarraf
Global System for Mobile Communication (GSM)
CS Domain
RAN
BTS
BSC
MSC
GMSC
PSTN
200 KHz
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HLR,
AUC
14. General Packet Radio Service (GPRS)
SGSN
MSC
BTS
GMSC
PSTN
BSC
200 KHz
• Introduced in GSM release 97, General Packet Radio Service (GPRS) is a 2.5G packet
data network that shares the radio access network with GSM but has a separate
Packet Switch (PS) core network.
• In a GSM/GPRS network, data traffic is forwarded through the PS domain, while voice
and SMS traffic goes through the CS domain.
• GPRS consists of Serving GPRS Support Nodes (SGSN) and Gateway GPRS Nodes
(GGSN). SGSNs and GGSNs support IP mobility tunnels based on the GPRS Tunneling
Protocol (GTP),GPRS has theoretical data rates between 56 and 114 Kbps.
Ali Al Sarraf
RAN
SGSN
External
Data
Network
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15. Enhanced Data Rates For GSM Evolution (EDGE)
Ali Al Sarraf
• Introduced in release 99, Enhanced Data Rates For GSM Evolution (EDGE) provides
coding and modulation improvements to GPRS that support minimum 3G data rates
from 236 Kbps to 473 Kbps depending on coding and modulation techniques used.
EDGE does not introduce any changes to the network other than coding and
modulation enhancements to the air interface to increase data speed.
PS Domain
GGSN
SGSN
RAN
BTS
External
Data
Network
GMSC
PSTN
HLR
AuC
BSC
MSC
CS Domain
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16. • UMTS release 5 (R5) introduced big changes to the UMTS network. Beginning in R5, all traffic is
transported via the PS domain using IP. Because all traffic is now forwarded by the PS domain,
release 5 removes the circuit switch domain from the network architecture.
• Critical circuit switched functions, such as voice call setup, interconnecting with PSTN, and so on,
are preformed by the IP Multimedia Subsystem (IMS). An R5 compliant UE must communicate
with IMS using Session Initiation Protocol (SIP) signaling, and generate and receive voice over IP
traffic within the subscriber device.
• UMTS R5 also introduced High Speed Downlink Packet Access (HSDPA), and it is increased peak
downlink throughput to 14.4 Mbps.
SGSN
Ali Al Sarraf
UMTS Release 5
IMS
GGSN
Voice, Data over IP
External
Data
Network
HSS
RAN
5 MHz
Node
B
RNC
PSTN
MSC
Server
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BICC
WCDMA
MGW
MGW
PSTN
17. • With the introduction of High Speed Uplink Packet Access (HSUPA), UMTS
release 6 increased the peak uplink speed to 5.76 Mbps. UMTS R6 also
enhanced IMS, and introduced Multimedia Broadcast Multicast Services
(MBMS) to support broadcast services such as Mobile TV.
• MBMS offers broadcast and/or multicast, unidirectional, point to multipoint
, multimedia flows.
• Broadcast and multicast are two completely different services. A broadcast
service is transmitted to all user devices which have the service activated in
their equipment. A service provider does not attempt to charge for limit the
broadcast transmission.
• In contrast, a multicast service is subscription-based. A UE must have
subscribed to the service and explicitly joined the multicast group to receive
the multicast transmission. A service provider may track, control, and charge
for multicast transmission.
• Examples of possible MBMS applications include audio/video streaming,
audio/video downloading, file downloading, and text/image distribution.
Ali Al Sarraf
UMTS Release 6
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18. UMTS Release 6
MBMS
RAN
5 MHz
WCDMA
HSUPA
Node
B
IMS
RNC
HSS
External
Data
Network
Ali Al Sarraf
PS Domain
SGSN
GGSN
PSTN
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19. UMTS Release 7
MBMS
PS Domain
SGSN
GGSN
RAN
5 MHz
WCDMA
HSPA+
MIMO
Node
B
Ali Al Sarraf
• Along with enhancing IMS, UMTS Release 7 introduced Multiple Input
Multiple Output (MIMO) antenna technology and High Speed Packet
Access+ (HSPA+). MIMO antenna systems significantly improve radio
network throughput and coverage. HSPA+ with 2X2 MIMO increases uplink
speeds to 11.5 Mbps and downlink speeds to 22Mbps.
IMS
RNC
HSS
External
Data
Network
PSTN
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20. • UMTS release 8 introduce the Evolved Universal Terrestrial Radio Access
Network (E-UTRAN) And the Evolved Packet Core (EPC).
• To reduce latency, the E-UTRAN collapsed the UMTS Node B and RNC
functionality into the evolved NodeB ( eNodeB). In addition to 5Mhz, the EUTRAN radio access network supports 1.4,3,10,15 and 20MHz Channels.
• R8 with 2X2 MIMO and 64 QAM modulation increases UL speeds to 23
Mbps, and DL Speeds to 42 Mbps.
• In the evolved packet core, the SGSN and GGSN are Replaced by the Serving
Gateway (S-GW) and Packet Data Network Gateway (P-GW). The Mobility
Management Entity (MME) manages UE mobility and paging functions.
Ali Al Sarraf
UMTS Release 8 (LTE)
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21. UMTS Release 8 (LTE)
MBMS
HSS
MME
RAN
Node
B
1.4 – 20 MHz
S-GW
P-GW
IMS
PSTN
Ali Al Sarraf
Evolved Packet Core
External
data
network
Evolved UTRAN
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22. • The UMTS release 8 architecture consists of the EPC, E-UTRAN, and user
entities (UEs).
• The Evolved Universal Terrestrial Access Network (E-UTRAN) is defined by
UMTS Release 8 as Long Term Evolution (LTE).
• System Architecture Evolution (SAE) defines the Evolved Packet Core (EPC).
The EPC is an all IP, packet switched network.
• The Evolved Packet System (EPS) includes the EPC, LTE, and the user
terminals called User Equipment (UE).
MME
S-GW
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EPS Architecture
P-GW
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UE
eNodeB
eNodeB
UE
23. Evolved UMTS Radio Access Network (E-UTRAN)
S1
MME/S-GW
S1
S1
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MME/S-GW
S1
X2
E-UTRAN
X2
X2
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24. • Radio Recourse Management (RRM): like radio bearer control and radio admission
control.
• IP header compression and encryption od the users data stream.
• Uplink/Downlink radio resource allocation in both the pulink and downlink.
• Transfer of paging messages over the air.
• Transfer of broadcast information over the air.
• Selection of the MME when attached to network.
• Handover management.
MME
S-GW
P-GW
Ali Al Sarraf
eNodeB Functions
External
Data
Network
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eNodeB
25. • Evolved UMTS Radio Access Network (E-UTRAN) contains a single elements
known as the evolved Node B (eNB). The eNB supports all the user plane
and control plane protocols to enable communication with the UE. It also
supports radio resource management, admission control, scheduling , uplink
QoS enforcement, cell broadcast, encryption and compression
/decompression of user data.
• The eNB is connected to the core network on the S1 interface. The S1
interface allows the eNB to communicate with Mobility Management Entity
(MME) via the S1-MME a many to many relationship between eNB and
SGW/MME.
• The eNB are also networked together using the X2 interface, the X2
interface is based on the same set of protocols as the S1 and is primarily in
place to allow user plane tunneling of packets during handover to minimize
packet loss.
Ali Al Sarraf
eNodeB Functions
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26. X2 Interface
Multi-cell RRM (Radio Recourse Management)
Handover functions: handover cancellation.
Uplink load Management.
Tunneling of user packets.
Ali Al Sarraf
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X2
eNodeB
eNodeB
X2
X2
eNodeB
Evolved -UTRAN
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27. User Equipment
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The User Equipment (UE) must preform the following functions:
• Signal network entry and other state changes.
• Report its tracking area location while in idle mode.
• Request UL grants to transmit data while in active mode.
MME
S-GW
P-GW
External
Data
Network
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eNodeB
28. The Evolved Packet Core network is an all IP, packet switched network. The
EPC consists of:
• Mobility Management Entity (MME) : key control node for the LTE access
network.
• Serving Gateway (S-GW) : routes and forwards data packets.
• Packet Data Network Gateway (P-GW) : provides connectivity to external
packet data networks.
External
Data
P-GW
Network
EPC
MME
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EPC Components
S-GW
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eNodeB
29. Mobility Management Entity (MME)
Idle mode UE tracking and paging.
Bearer activation/deactivation.
Chooses S-GW for UE.
Authentication with HSS.
Assigns temporary identity to UE.
MME
S-GW
Ali Al Sarraf
•
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P-GW
External
Data
Network
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eNodeB
30. Mobility Management Entity (MME)
The primary signaling node in the EPC.
Managing and storing UE context.
Idle-state mobility control.
Distributing paging (Communicate with UE when the network does not
know the cell location for UE) massages to eNBs.
• Security control.
• Roaming , Authentications.
• Admission control and communication with the home HSS on the S6a
interface.
MME
S-GW
P-GW
Ali Al Sarraf
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External
Data
Network
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eNodeB
31. Serving Gateway
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Internet
S5 Interface
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•
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There are two Gateways in the EPC:
One facing towards the E-UTRAN (the S-GW).
One facing towards the external packet data
network (the P-GW).
S-GW functions:
Anchoring the user plane for inter-eNB
handover.
Anchoring the user plane for inter -3GPP
mobility (LTE with 3G).
Packet routing and forwarding.
S1 Interface
eNodeB
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X2 Interface
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P-GW functions:
Provide connectivity to the PDN and Packet routing for the UE.
Allocates IP addresses to the UE.
The entry and exit point for UE connectivity with external data networks.
Accounting and QoS.
Anchor the user plan during MME/SGW handover and during 3GPP-to Non3GPP handover.
Ali Al Sarraf
Packet Data Network Gateway
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33. • The HSS is a user database that stores subscription-related information to
support other call control and session management entities.
• It’s a storehouse for user identification, numbering , service profiles and
location.
• It is mainly involved in user authentications and authorization.
• Generates security-related information.
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Home Subscriber Server (HSS)
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34. LTE SAE Reference Points
IMS
SGI
S2a
P-GW
S3
MME
S11
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SGI
UMTS
Non-3GPP
access
Internet
S5
S-GW
S1-MME
S1-U
X2
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eNodeB
eNodeB
35. S1 Interface
Ali Al Sarraf
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S1 Functionalities are split into C-Plane and U-plane Functionalities :
The S1 Control Plane:
Delivering a signaling between the eNB and MME.
Handover signaling procedure.
Paging procedure.
NAS transport procedure.
The S1 User plane:
• Responsible for delivering user data between the eNB and S-GW.
MME
S-GW
S1-MME
P-GW
SGi
S1-U
Uu
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Uu
UE
eNodeB
X2
eNodeB
UE
36. • S2a/b: it provides the user plane with related control and mobility support
between a trusted/ not-trusted non-3GPP Ip access and the SAE anchor.
• S2a ( Between Trusted Non 3G and LTE P-GW)
• S2b( Between Non- Trusted Non 3G and LTE P-GW)
• S3: it enables user and bearer information exchange for inter 3GPP access
system mobility in idle and/or active state. It is based on Gn reference point
defined between SGSNs.
• SGI: it is the reference point between the inter AS anchor and the packet
data network, packet data network may be an operator external public or
private packet data network or an intra operator packet data network.
Ali Al Sarraf
LTE Reference Points
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37. Interworking with trusted 3GPP & Non 3GPP
Networks
• Trusted Non-3GPP Access
• Non-3GPP IP access describes access to the EPC by technologies not defined
by 3GPP. Non-3GPP access technologies include WiFi, WiMAX, fixed access
such as cable or DSL, and so on. System Architecture Evolution (SAE)
describes trusted and untrusted non-3GPP IP access.
• The individual carrier must decide if a non-3GPP network is trusted or
untrusted. This is a business decision and dies not depend on the access
network technology.
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• Serving GPRS Support Node (SGSN)
• In 2G and 3G systems, the Serving GPRS Support Node (SGSN) is responsible
for the delivery of data packets to and from UEs within its geographical
service area. The SGSN provides the interfaces between the MME and S-GW
in the EPC.
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38. Interworking with trusted 3GPP & Non 3GPP
Networks
PCRF
SGSN
S4, S12
GERAN,
UTRAN
HSS
MME
S-SW
P-GW
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S3
S2a/S2c
UE
eNodeB
Trusted
non-3GPP
Access
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39. Evolved Packet Data Gateway (ePDG)
• The evolved Packet Data Gateway (ePDG) connects the LTE network to an
untrusted, non-3GPP network. To access the LTE network, the non-3GPP
subscriber must establish an IP Security (IPSec) tunnel via the ePDG. The
ePDG is the encapsulation- de capsulation point for Mobile IP / Proxy
Mobile IP (MIP/PMIP).
• The ePDG also authenticates, authorizes, and enforces QoS policies in
conjunction with the 3GPP AAA server.
3GPP AAA Server
• The 3GPP AAA server provides authentication, authorization, and
accounting services for untrusted non-3GPP IP access.
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Interworking with Untrusted 3GPP networks
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40. Interworking with Untrusted 3GPP networks
HSS
MME
S-SW
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PCRF
P-GW
S2a/S2c
ePDG
3GPP
AAA
UE
eNodeB
UnTrusted
non-3GPP
Access
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41. Two additional interfaces are specified, S3 and S4:
• S3 supports the user and bearer information exchange so the SGSN and the
MME during handover/cell reselection.
• QoS and user context will be exchange so the target system has all the
information required to re-establish the bearer on the new cell.
• S3 is based on the IP GN interface designed for 2G/3G core architecture.
• S4 carries the user plane data between the SGSN and the S-GW.
• The S-GW play the role of the mobility anchor in inter-system exchanges, it
has a very similar role to the GGSN in 2G/3G networks.
• The S4 interface is also based on the Gn interface.
Ali Al Sarraf
Inter working with 2G/3G Networks
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42. Trusted access (the operator owns and operates the WLAN network):
• The user data sent directly to the P-GW via the IP based S2 interface.
• Information relating to subscriber profiles, authentication vectors, network
identity, charging and QoS information may all be provides to the WLAN
access via the Ta interface.
• The information is provided via the 3GPP AAA server which acts as an interworking point between the 3GPP and IETF worlds.
• The main purpose of the 3GPP AAA server is to allow end to end interaction,
such as authentications to take place using 3GPP credentials stored in the
HSS via the Wx interface.
Non-trusted case (a corporate entity has its own WLAN network):
• The ePDG (evolved Packet Data Gateway) element carried all the traffic from
the WLAN via a secure tunnel (IPSec) over the Wn interface.
• The Wn interface allows the user related data from the HSS via the 3GPP
AAA server, to be exchanged, ensuring proper tunneling and encryption
between the user terminal and the P-GW.
Ali Al Sarraf
NON-3GPP Access
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43. • HeNB deployed as small E-UTRAN cells in domestic, small office etc.
• HeNB interconnects with the evolved Packet Core, over a fixed broadband
access network.
• Support for full mobility into and out of a HeNB Coverage including service
continuity where applicable.
• Operators and owners of HeNB will be able to control access to the
resources provided.
Ali Al Sarraf
LTE Femto Cells
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44. • Femto Functions:
• HNB and HeNB deployed as small UTRA and E-UTRAN cells, respectively, in
domestic, small office and similar environments.
• The HNB and HeNB interconnects with the 3G core and evolved Packet
Core, respectively, over a fixed broadband access network.
• Support for full mobility into and out of a HeNB coverage including service
continuity where applicable.
• Operators and owners of HeNB and HNB will be able to control access to the
resources provided.
Ali Al Sarraf
Femto Cell
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45. Handover
• Source eNB configures UE measurements.
• Source eNB receives UE measurement reports.
• HO decision is made and target eNB is selected by the source eNB.
S-GW
S1-MME
S1-U
Source
eNodeB
Control plane
User plane
User data
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MME
X2
eNodeB
Target
Measurements
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UE
46. Handover
• HO request sent from source eNB to target eNB.
• Target eNB performs admission control and accespts the HO request.
• HO Ack. Sent to source eNB from target eNB.
S-GW
S1-MME
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MME
S1-U
HO Request
Source
eNodeB
Control plane
User plane
User data
HO ACK.
eNodeB
Target
Measurements
46
UE
47. Handover
• HO command is sent to the UE ( RRC connection reconfiguration including
the mobility control info.
• Data forwarding initiated towards the target eNB.
S-GW
S1-MME
S1-U
Source
eNodeB
Control plane
User plane
User data
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MME
X2
eNodeB
Target
HO Command
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UE
48. Handover
• UE accesses the target eNB and confirms the HO (RACH procedure is
initiated and RRC connection reconfiguration complete is sent)
S-GW
S1-MME
Source
eNodeB
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MME
S1-U
eNodeB
Target
X2
HO Confirm
Control plane
User plane
User data
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UE
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Target eNB requests EPC to switch the data path
eNB MME : path switch request.
MME S-GW: modify bearer request.
S-GW MME: modify bearer response.
MME
eNB: path switch request ACK.
Target eNB notifies the source eNB that UE resources can be released.
MME
S-GW
S1-MME
Source
eNodeB
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Handover
S1-U
eNodeB
Target
X2
HO Confirm
Control plane
User plane
User data
UE
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51. Self Organizing Networks
Automatic software management
Self test.
automatic neighbor relation configuration.
Tracking area planning .
Existing
eNodeB
Physical cell ID planning.
Load balancing.
Handover optimaisations.
New eNodeB
DHCP/DNS
S-GW
MME
OSS
Ali Al Sarraf
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Configuration
And
performance
51
52. • The objective of the self- configuration SON functionality is to reduce the
amount of human intervention in the overall installation process by
providing “plug and play” functionality in the eNodeBs.
• Self-Configuration of eNodeBs will reduce the amount of manual processes
involved in the planning, integration and configuration of new eNodeBs.
• This will result in a faster network deployment and reduced costs for the
operator.
Ali Al Sarraf
Self Organizing Networks (SON)
52
53. SON Processing
• After switching in eNB, its called Self Configuration starts.
• The eNB is already physically connected with the network, but the RF is still
switched off. An IP address and a connection to an O&M is assigned to the
eNB.
• After an authentication in the network, the eNB gets an association to the
MME and S-GW, and the connections to the core (S1)and to the neighbored
eNBs (X2) are established. Ig available there may be a software update.
• Also the physical cell identities (PCI) for all supported cells in the eNB are
assigned here, as these are required to go on air.
Self configuration
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SON Processing
Self Optimization
53
Self Healing
Switch on RF
54. SON Processing
The Self Optimization:
• This stage starts by switching in the RF.
• Mobiles may now connect with the cells and return feedback to improve
the initial radio configuration and also to adopt the to traffic load or
measured propagation conditions.
• For this feedback, existing RRC measurements have been extended.
Self configuration
Ali Al Sarraf
• After these basic setup procedures, the eNB gets the initial radio
configuration. This is comprised by the initial neighbor list, the coverage and
capacity related parameter configuration like transmission power, antenna
tilt, and all remaining parameters for operation. These parameters are
finally optimized at the next stage, the Self optimization.
Self Optimization
54
Self Healing
Switch on RF
55. SON Processing
Self Healing:
In the case of a failure, the so called Self Healing applies.
In case of a hardware failure, the eNB switches to a spare part.
In case of a failure was caused by a not properly running software update,
the eNB reloads a former software.
• When none of these remaining eNBs change their setting in order to fill the
coverage gap created by the failure.
Self configuration
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•
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Self Optimization
55
Self Healing
Switch on RF