Aim of Long Term Evolution Increased Capacity Reduce Network
Complexity Lower deployment and operating cost
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What is LTE ? 3GPP Long Term Evolution, referred to as LTE and
marketed as 4G LTE, is a standard for wireless communication of
high-speed data for mobile phones and data terminals. It is based
on the GSM/EDGE and UMTS/HSPA network technologies, increasing the
capacity and speed using new modulation techniques. In Nov. 2004,
3GPP began a project to define the long-term evolution (LTE) of
Universal Mobile Telecommunications System (UMTS) cellular
technology Higher performance Backwards compatible Wide application
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LTE Key factors LTE High Data Rates > 100 Mbps Downlink >
50 Mbps Uplink Channel Setup < 100 ms Why ? Mobile Broadband
Tendency Customers need for more Spectral Efficience platform for
Mobile data communicattion. ( Cost of Bits / Hz) Efficient Reducing
OPEX & CAPEX Easy to deploy (self configuring/optimizing) TDD /
FDD & Spectrum Flexibility New Services (IPTV & Games in
Real Time) High Performance for Broadcast Services Wide Range of
Terminals Increase Service Provisioning
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Evolution of Radio Access Technologies LTE (3.9G) : 3GPP
release 8~9 LTE-Advanced : 3GPP release 10+ 7 802.16d/e
802.16m
LTE (Long Term Evolution) Radio Side (LTE Long Term Evolution)
Improvements in spectral efficiency, user throughput, latency
Simplification of the radio network Efficient support of packet
based services Network Side (SAE System Architecture Evolution)
Improvement in latency, capacity, throughput Simplification of the
core network Optimization for IP traffic and services Simplified
support and handover to non-3GPP access technologies
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Evolution Path Architecture The pay load is to be directed to a
tunnel (eUTRAN) Payload goes directly from the evolved node B to
the Gateway Control plane is directed at the Mobility management
end. LTE
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WCDMA (HSPA) x LTE Access Network WCDMA System Architeture LTE
System Architeture RAN
LTE eNodeB LTE eNodeB Coding, Interleaving, modulation &
typical layer functions. ARQ, Header Compression & layer
functions Security Functions (Ciphering / Integrity Protection )
eNodeB take decisions about Handover & scheduling for uplink
and downlink. Radio Resources Control functions Connected to the
Core Network with S1 Interface (similar as Iu) X2 is similar to Iur
Interface, mainly used to support the Active Mode Mobility.
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WCDMA (HSPA) x LTE Core WCDMA System Architeture LTE - SAE
System Architeture Evolution
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WCDMA LTE - Core LTE Core Introduction of EPC Evolved Packet
Core SAE just covers Packet Switched Domain HSS is the same as HLR
in GSM/WCDMA network HSS uses the S6 interface eNodeB is connected
to the EPC by S1 Interface EPC acts as anchor in the SAE Core
Network for mobility Charging Management of Subscriber Mobility
Management ( roaming ) QOS Handling Policy Control of Data Flows
Interconection with External Networks
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SAE: System Architecture Evolution HSS HLR AAA PDN GW Serv GW
MME SGSN PCRF LTE 2G 3G Non-3GPP Non-trusted Non-3GPP Trusted Eg
cdma Wx* Gb Iu-C S3 S4 S1-C S1-U S12 S10 S11 S5/S8 SGi S6c S7 S7c
S7b S7a Ta* S2a Wa* Wn* Wm* IP networks S9 S6a Gr S101/102 ePDG S2b
Wn* S2c S103 WSM module Mobility Management Entity (MME): The MME
manages mobility, UE identities and security parameters The Serving
Gateway is the node that terminates the interface towards LTE RAN
PDN Gateway (PDN GW): The PDN Gateway is the node that terminates
the SGi interface towards the PDN
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MME Functionality Roaming (S6a towards home HSS) Authentication
SAE GW selection Idle mode mobility handling Tracking Area Update
Paging Mobility handling of inter-MME (pool) handover (triggered by
eNodeB) inter-RAT handover (triggered by eNodeB) QoS negotiation
with UE and eNodeB Security Ciphering and integrity protection of
NAS signalling Secure control signalling transport on S1 interface
(unless taken care of by a SEG (Security Gateway)) O&M security
(?) SAE CN Architecture SGi MME S1-MME S1-U S11 X2 S10 eNodeB S3 S4
SGSN SAE GW
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SAE GW Functionality PDN SAE GW: Policy Enforcement Per-user
based packet filtering (by e.g. deep packet inspection) Charging
Support User plane anchor point for mobility between 3GPP accesses
and non-3GPP accesses routing of user data towards the S-GW
Security O&M security (?) Lawful Intercept Serving SAE GW: User
plane anchor point for inter-eNB handover (within one pool) User
plane anchor point for inter-3GPP mobility routing of user data
towards the eNodeB routing of user data towards the P-GW routing of
user data towards the SGSN (2G and 3G) or RNC (3G with Direct
Tunnel) Security Secure user data transport on S1 interface (unless
taken care of by a SEG (Security Gateway)) O&M security (?)
Lawful Intercept The PDN SAE GW and the Serving SAE GW may be
implemented in one physical node or separated physical nodes. SAE
CN Architecture SGi MME S1-MME S1-U S11 X2 S10 eNodeB S3 S4 SGSN
SAE GW
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Key LTE radio access features LTE radio access Downlink: OFDM
Uplink: SC-FDMA Advanced antenna solutions Diversity Beam-forming
Multi-layer transmission (MIMO) Spectrum flexibility Flexible
bandwidth New and existing bands Duplex flexibility: FDD and TDD 20
MHz1.4 MHz TX SC-FDMA OFDMA
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LTE Access Network LTE employs OFDMA in DL and SC-FDMA in UL
LTE basic charactheristics: Flexibility bandwidth (from 1.4 Mhz to
20 MHZ). Orthogonally in uplink and downlink. Modulation : QPSK,
16QAM, 64QAM. FDD (frequency division duplex), HD FDD ( half
frequency division duplex & TDD (time Division Duplex are
supported). Advanced Antenna Technology MIMO is used in downlink to
allow high peak rates.
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UL-SCH Channel Structure Downlink and Uplink PCH DL-SCH PCCH
Logical Channels type of information (traffic/control) Transport
Channels how and with what characteristics (common/shared/mc/bc)
Downlink Uplink PDSCH Physical Channels bits, symbols, modulation,
radio frames etc MTCH MCCH BCCH DTCH DCCH DTCH DCCH CCCH PRACH RACH
CCCH MC H BCH PUSCHPBCHPCFICHPUCCH ACK/NACK CQI Scheduling req.
-Sched TF DL -Sched grant UL -Pwr Ctrl cmd -HARQ info pri sec
PMCHPHICHPDCCH ACK/NACK PDCCH info
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LTE Logical Channels ( type of Information) BCCH ( Broadcast
Control Channel ) Used for transmission of system control
information to all mobiles in the cell. Prior to access the network
the mobile needs to read the information on BCCH to find out how
the system is configured, for example the bandwidth. PCCH ( Paging
Control Channel ) used for Paging of Mobiles whose location on cell
level in not know to the network. DCCH ( Dedicated Control Channel
) Used for Transmission of control information to/from mobile. This
channel is used for individual configuration of Terminals such as
differents kinds of handover messages.
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LTE Logical Channels ( type of Information) MCCH ( Multicast
Control Channel ) used for transmission of control information
required for reception of the MTCH. DTCH ( Dedicated Traffic
Channel ) used for transmission of user data to/from a mobile
terminal. This is the logical channel type used for transmission of
all uplink and non-MBMS downlink user data. MTCH ( Multicast
Traffic Channel ) used for downlink transmission of MBMS
services.
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LTE Transport Channels BCH ( Broadcast Channel ) Fixed Tranport
Format Used for identification of cells & transmission of BCCH
logical channel. RACH ( Random Access Channel ) Used for Access the
Network from theTerminal. Limited control information and colission
risk. PCH ( Paging Channel ) is used for transmission of paging
information on the PCCH logical channel. The PCH supports
discontinuous reception (DRX) to allow the mobile terminal to save
battery power by sleeping and waking up to receive the PCH only at
predefined time instants.
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LTE Transport Channels DL-SCH (Downlink Shared Channel) Used
for transmission of data in LTE DL SCH TTI is 1 ms Support Features
as Dynamic Rate Adaptation & Channel Dependent Scheduling in
time and frequency domain. MCH ( Multi Cast Channel) Used to
support MBMS UL - SCH ( Uplink Shared Channel ) Used for
transmission of data in LTE UL SCH TTI 1 ms Support Features as
Dynamic Rate Adaptation & Channel Dependent Scheduling in time
and frequency domain.