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Ahmed Hamza Ahmed Hamza

[email protected] [email protected]

Network Systems Laboratory Network Systems Laboratory

Simon Fraser University Simon Fraser University

October 13, 2009 October 13, 2009

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Outline

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1 IntroductionIntroduction

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2 LTE ArchitectureLTE Architecture

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3 LTE Radio InterfaceLTE Radio Interface

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4 Multimedia Broadcast/Multicast ServiceMultimedia Broadcast/Multicast Service

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5 LTE Deployment ConsiderationsLTE Deployment Considerations

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6 Work Related to Video StreamingWork Related to Video Streaming

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Outline

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Introduction

In November 2004 3GPP began a project to deﬁne the long-term In November 2004 3GPP began a project to deﬁne the long-term evolution of UMTS cellular technology.

evolution of UMTS cellular technology.

Related peciﬁcations are formally known as the evolved UMTS Related peciﬁcations are formally known as the evolved UMTS terrestrial radio access (E-UTRA) and evolved UMTS terrestrial terrestrial radio access (E-UTRA) and evolved UMTS terrestrial radio access network (E-UTRAN).

radio access network (E-UTRAN).

First version is documented in Release 8 of the 3GPP First version is documented in Release 8 of the 3GPP speciﬁcations.

speciﬁcations.

Commercial deployment not expected before 2010, but there are Commercial deployment not expected before 2010, but there are currently many ﬁeld trials.

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LTE Development Timeline

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Introduction

Next Generation Mobile Network (NGMN) Alliance

19 worldwide leading mobile operators 19 worldwide leading mobile operators

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LTE Targets

Higher performance Higher performance

100 Mbit/s peak downlink, 50 Mbit/s peak uplink 100 Mbit/s peak downlink, 50 Mbit/s peak uplink

1G for LTE Advanced 1G for LTE Advanced

Faster cell edge performance Faster cell edge performance

Reduced latency (to 10 ms) for better user experience Reduced latency (to 10 ms) for better user experience Scalable bandwidth up to 20 MHz

Scalable bandwidth up to 20 MHz

Backw

Backwards ards compatiblecompatible

Works with GSM/EDGE/UMTS systems Works with GSM/EDGE/UMTS systems

Utilizes existing 2G and 3G spectrum and new spectrum Utilizes existing 2G and 3G spectrum and new spectrum

Supports hand-over and roaming to existing mobile networks Supports hand-over and roaming to existing mobile networks

Reduced capex/opex via simple architecture Reduced capex/opex via simple architecture

reuse of existing sites and multi-vendor sourcing reuse of existing sites and multi-vendor sourcing

Wide application Wide application

TDD (unpaired) and FDD (paired) spectrum modes TDD (unpaired) and FDD (paired) spectrum modes Mobility up to 350kph

Mobility up to 350kph

Large range of terminals (phones and PCs to cameras) Large range of terminals (phones and PCs to cameras)

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LTE Architecture LTE Architecture

Outline

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LTE Architecture

LTE encompasses the evolution of: LTE encompasses the evolution of:

the radio access through the E-UTRAN the radio access through the E-UTRAN the non-radio aspects under the term

the non-radio aspects under the term System ArchitectureSystem Architecture Evolution (SAE)

Evolution (SAE)

Entire system composed of both LTE and SAE is called the Entire system composed of both LTE and SAE is called the Evolved Packet System (EPS)

Evolved Packet System (EPS)

At a high-level, the network is comprised of: At a high-level, the network is comprised of:

Core Network (CN), called

Core Network (CN), called Evolved Packet Core (EPC)Evolved Packet Core (EPC) in SAEin SAE access network (E-UTRAN)

access network (E-UTRAN)

A

A bearer bearer is an IP packet flow with a defined QoS between theis an IP packet flow with a defined QoS between the gateway and the User Terminal (UE)

gateway and the User Terminal (UE)

CN is responsible for overall control of UE and establishment of CN is responsible for overall control of UE and establishment of the bearers

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LTE Architecture

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LTE Architecture

Main logical nodes in EPC are: Main logical nodes in EPC are:

PDN Gateway (

PDN Gateway (P-GWP-GW)) Serving Gateway (

Serving Gateway (S-GWS-GW)) Mobility Management Entity (

Mobility Management Entity (MMEMME))

EPC also includes other nodes and functions, such: EPC also includes other nodes and functions, such:

Home Subscriber Server

Home Subscriber Server (HSS)(HSS)

Policy Control and Charging Rules Function (PCRF) Policy Control and Charging Rules Function (PCRF)

EPS only provides a bearer path of a certain QoS, control of EPS only provides a bearer path of a certain QoS, control of multimedia applications is provided by the IP Multimedia

multimedia applications is provided by the IP Multimedia Subsystem (IMS), which considered outside of EPS

Subsystem (IMS), which considered outside of EPS

E-UTRAN solely contains the evolved base stations, called E-UTRAN solely contains the evolved base stations, called eNodeB

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LTE Architecture

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Outline

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LTE Radio Interface

LTE Radio Interface Architecture

eNB and UE have

eNB and UE have control plane control plane andand data plane data plane protocol layersprotocol layers

Data enters Data enters proces

processing chain sing chain inin the form of IP

the form of IP

packets on one of packets on one of the SAE bearers the SAE bearers

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Protocol Layers

IP packets are passed through multiple protocol entities: IP packets are passed through multiple protocol entities:

Packet Data Convergence Protocol (PDCP) Packet Data Convergence Protocol (PDCP)

IP

IP header compresheader compression based sion based on on RobRobust ust HeadeHeader r CompCompressiressionon (ROHC)

(ROHC)

ciphering and integrity protection of transmitted data ciphering and integrity protection of transmitted data

Radio Link Control (RLC) Radio Link Control (RLC)

segmentation/concatenation segmentation/concatenation retransmission handling

retransmission handling

in-sequence delivery to higher layers in-sequence delivery to higher layers

Medium Access Control (MAC) Medium Access Control (MAC)

handles hybrid-ARQ retransmissions handles hybrid-ARQ retransmissions uplin

uplink k and downlink scheduland downlink scheduling at ing at the eNodeBthe eNodeB

Physical Layer (PHY) Physical Layer (PHY)

coding/decoding coding/decoding modulation/demodulation (OFDM) modulation/demodulation (OFDM) multi-antenna mapping multi-antenna mapping

other typical physical layer functions other typical physical layer functions

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LTE Radio Interface

Communication Channels

RLC offers services to PDCP in the form of

RLC offers services to PDCP in the form of radio bearers radio bearers MAC offers services to RLC in the form of

MAC offers services to RLC in the form of logical channels logical channels PHY offers services to MAC in the form of

PHY offers services to MAC in the form of transport channels transport channels A

A logical channel logical channel is defined by the type of information it carries.is defined by the type of information it carries. Generally classified as:

Generally classiﬁed as:

a control channel, used for transmission of control and a control channel, used for transmission of control and

configuration information necessary for operating an LTE system configuration information necessary for operating an LTE system a traffic channel, used for the user data

a trafﬁc channel, used for the user data

A

A transport channel transport channel is deﬁned by how andis deﬁned by how and

with what characteristics the information is transmitted over the with what characteristics the information is transmitted over the radio interface

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Channel Mapping

BCCH: Broadcast BCCH: Broadcast CCCH: Common CCCH: Common PCCH: Paging PCCH: Paging MCCH: Multicast MCCH: Multicast DTCH:

DTCH: Dedicated Dedicated TTrafficraffic MTCH: Multicast Traffic MTCH: Multicast Traffic DL-SCH: Downlink Shared DL-SCH: Downlink Shared MCH: Multicast MCH: Multicast BCH: Broadcast BCH: Broadcast PCH: Paging PCH: Paging

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LTE Radio Interface

Radio Link Control (RLC) Layer

Depending on the scheduler decision, a certain amount of data is Depending on the scheduler decision, a certain amount of data is selected for transmission from the RLC SDU buffer and the SDUs selected for transmission from the RLC SDU buffer and the SDUs are segmented/concatenated to create the RLC PDU. Thus, for are segmented/concatenated to create the RLC PDU. Thus, for LTE the RLC PDU size varies dynamically

LTE the RLC PDU size varies dynamically

Each RLC PDU includes a header, containing, among other Each RLC PDU includes a header, containing, among other

things, a sequence number used for in-sequence delivery and by things, a sequence number used for in-sequence delivery and by the retransmission mechanism

the retransmission mechanism

A retransmission protocol operates between the RLC entities in A retransmission protocol operates between the RLC entities in the receiver and transmitter.

the receiver and transmitter.

Receiver monitors sequence numbers and identiﬁes missing PDUs Receiver monitors sequence numbers and identiﬁes missing PDUs

Although the RLC is capable of handling transmission errors, Although the RLC is capable of handling transmission errors, error-free delivery is in most cases handled by the MAC-based error-free delivery is in most cases handled by the MAC-based hybrid-ARQ protocol

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Medium Access Control (MAC) Layer

Data on a transport channel is organized into transport blocks. Data on a transport channel is organized into transport blocks. Each Transmission Time Interval (TTI), at most one transport Each Transmission Time Interval (TTI), at most one transport block of a certain size is transmitted over the radio interface block of a certain size is transmitted over the radio interface to/from a mobile terminal (in absence of spatial multiplexing) to/from a mobile terminal (in absence of spatial multiplexing) Each transport block has an associated Transport Format (TF) Each transport block has an associated Transport Format (TF)

speciﬁes how the block is to be transmitted over the radio interface speciﬁes how the block is to be transmitted over the radio interface (e.g. transport-block size, modulation scheme, and antenna

(e.g. transport-block size, modulation scheme, and antenna mapping)

mapping)

By varying the transport format, the MAC layer can realize By varying the transport format, the MAC layer can realize different data rates.

different data rates.

Rate control is therefore also known as transport-format selection Rate control is therefore also known as transport-format selection

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LTE Radio Interface

Hybrid ARQ (HARQ)

In hybrid ARQ, multiple parallel stop-and-wait processes are used In hybrid ARQ, multiple parallel stop-and-wait processes are used (this can result in data being delivered from the hybrid-ARQ

(this can result in data being delivered from the hybrid-ARQ

mechanism out-of-sequence, in-sequence delivery is ensured by mechanism out-of-sequence, in-sequence delivery is ensured by the RLC layer)

the RLC layer)

Hybrid ARQ is not applicable for all types of trafﬁc (broadcast Hybrid ARQ is not applicable for all types of trafﬁc (broadcast

transmissions typically do not rely on hybrid ARQ). Hence, hybrid transmissions typically do not rely on hybrid ARQ). Hence, hybrid ARQ is only supported for the DL-SCH and the UL-SCH

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Physical (PHY) Layer

Based on OFDMA with cyclic prefix in downlink, and on SC-FDMA Based on OFDMA with cyclic prefix in downlink, and on SC-FDMA with a cyclic prefix in the uplink

with a cyclic preﬁx in the uplink

Three duplexing modes are supported: full duplex FDD, half Three duplexing modes are supported: full duplex FDD, half duplex FDD, and TDD

duplex FDD, and TDD

Two frame structure types: Two frame structure types:

Type-1 shared by both full- and half-duplex FDD Type-1 shared by both full- and half-duplex FDD Type-2 applicable to TDD

Type-2 applicable to TDD

A radio frame has a length of 10 ms and contains 20 slots (slot A radio frame has a length of 10 ms and contains 20 slots (slot duration is 0.5 ms)

duration is 0.5 ms)

Two adjacent slots constitute a

Two adjacent slots constitute a subframe subframe of length 1 msof length 1 ms

Supported modulation schemes are: QPSK, 16QAM, 64QAM Supported modulation schemes are: QPSK, 16QAM, 64QAM Broadcast channel only uses QPSK

Broadcast channel only uses QPSK

Maximum information block size = 6144 bits Maximum information block size = 6144 bits CRC-24 used for error detection

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LTE Radio Interface

Type-1 Frame

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Type-2 Frame

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LTE Radio Interface

Scheduler in eNB (base station) allocates resource blocks (which Scheduler in eNB (base station) allocates resource blocks (which are the smallest elements of resource allocation) to users for

are the smallest elements of resource allocation) to users for predetermined amount of time

predetermined amount of time

Slots consist of either 6 (for long cyclic prefix) or 7 (for short cyclic Slots consist of either 6 (for long cyclic prefix) or 7 (for short cyclic prefix) OFDM symbols

preﬁx) OFDM symbols

Longer cyclic prefixes are desired to address longer fading Longer cyclic prefixes are desired to address longer fading Number of available subcarriers changes depending on Number of available subcarriers changes depending on transmission bandwidth (but subcarrier spacing is fixed) transmission bandwidth (but subcarrier spacing is fixed)

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Downlink Resource Block

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LTE Radio Interface

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To enable channel estimation in OFDM transmission, known To enable channel estimation in OFDM transmission, known reference symbols are inserted into the OFDM time-frequency reference symbols are inserted into the OFDM time-frequency grid.

grid.

In LTE, these reference symbols are jointly referred to as downlink In LTE, these reference symbols are jointly referred to as downlink reference signals.

reference signals.

Three types of reference signals are deﬁned for the LTE downlink: Three types of reference signals are deﬁned for the LTE downlink:

Cell-speciﬁc downlink reference signals Cell-speciﬁc downlink reference signals

transmitted in every downlink subframe, and span the entire downlink transmitted in every downlink subframe, and span the entire downlink cell bandwidth.

cell bandwidth.

UE-speciﬁc reference signal UE-speciﬁc reference signal

only transmitted within the resource blocks assigned for DL-SCH only transmitted within the resource blocks assigned for DL-SCH transmission to that speciﬁc terminal

transmission to that speciﬁc terminal

MBSFN reference signals MBSFN reference signals

Ahmed Hamza

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LTE Radio Interface

MAC Scheduler

eNB scheduler controls the time/frequency resources for a given eNB scheduler controls the time/frequency resources for a given time for uplink and downlink

time for uplink and downlink

dynamically controls the terminal(s) to transmit to and, for each of dynamically controls the terminal(s) to transmit to and, for each of these terminals, the set of resource blocks upon which the

these terminals, the set of resource blocks upon which the terminal’s DL-SCH should be transmitted

terminal’s DL-SCH should be transmitted

Scheduler dynamically allocates resources to UEs at each TTI Scheduler dynamically allocates resources to UEs at each TTI The scheduling strategy is implementation speciﬁc and not

The scheduling strategy is implementation speciﬁc and not speciﬁed by 3GPP

speciﬁed by 3GPP

scheduler selects best multiplexing for UE based on channel scheduler selects best multiplexing for UE based on channel conditions

conditions

preferably schedule transmissions to a UE on resources with preferably schedule transmissions to a UE on resources with advantageous channel condition

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Most scheduling strategies need information about: Most scheduling strategies need information about:

channel conditions at the terminal channel conditions at the terminal

buffer status and priorities of the different data ﬂows buffer status and priorities of the different data ﬂows

interference situation in neighboring cells (if some form of interference situation in neighboring cells (if some form of interference coordination is implemented)

interference coordination is implemented)

UE transmits UE transmits

channel-status reports reﬂecting the instantaneous channel quality channel-status reports reﬂecting the instantaneous channel quality in the time and frequency domains

in the time and frequency domains inf

informatioormation n necesnecessary sary to to determidetermine ne the the approappropriate antennapriate antenna processing in case of spatial multiplexing

processing in case of spatial multiplexing

Downlink LTE considers the following schemes as a scheduler Downlink LTE considers the following schemes as a scheduler algorithm:

algorithm:

Frequency Selective Scheduling (FSS) Frequency Selective Scheduling (FSS) Frequency Diverse Scheduling (FDS) Frequency Diverse Scheduling (FDS) Proportional Fair Scheduling (PFS) Proportional Fair Scheduling (PFS)

Interference coordination, which tries to control the inter-cell Interference coordination, which tries to control the inter-cell interference on a slow basis, is also part of the scheduler interference on a slow basis, is also part of the scheduler

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Multimedia Broadcast/Multicast Service

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Multimedia Broadcast/Multicast Service (MBMS)

Introduced for WCDMA (UMTS) in Release 6 Introduced for WCDMA (UMTS) in Release 6

Supports multicast/broadcast services in a cellular system Supports multicast/broadcast services in a cellular system

Same content is transmitted to multiple users located in a speciﬁc Same content is transmitted to multiple users located in a speciﬁc area (MBMS service area) in a unidirectional fashion

area (MBMS service area) in a unidirectional fashion

MBMS extends existing 3GPP architecture by introducing: MBMS extends existing 3GPP architecture by introducing:

MBMS Bearer Service MBMS Bearer Service

delivers IP multicast datagrams to multiple receivers using minimum delivers IP multicast datagrams to multiple receivers using minimum radio and

radio and netwonetwork rk resourresources and ces and provprovides an ides an efﬁciefﬁcient and ent and scalascalableble means to

means to distribdistribute ute mulmultimedtimedia ia contencontent t to to mobimobile le phonesphones

MBMS User Services MBMS User Services

streaming services - a continuous data ﬂow of audio and/or video is streaming services - a continuous data ﬂow of audio and/or video is delivered to the user’s handset

delivered to the user’s handset

download services - data for the ﬁle is delivered in a scheduled download services - data for the ﬁle is delivered in a scheduled transmission timeslot

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Multimedia Broadcast/Multicast Service (MBMS)

QoS for transport of multimedia applications is not sufficiently high QoS for transport of multimedia applications is not sufficiently high to support a significant portion of the users for either download or to support a significant portion of the users for either download or streaming applications

streaming applications

The p-t-m MBMS Bearer Service does neither allow control, mode The p-t-m MBMS Bearer Service does neither allow control, mode adaptation, nor retransmitting lost radio packets

adaptation, nor retransmitting lost radio packets

Consequently, 3GPP included an application layer FEC based on Consequently, 3GPP included an application layer FEC based on Raptor codes for MBMS

Raptor codes for MBMS

MBMS User Services may be distributed over p-t-p links (if more MBMS User Services may be distributed over p-t-p links (if more efﬁcient)

efﬁcient)

Broadcast Multicast Service Center (BM-SC)

Broadcast Multicast Service Center (BM-SC) nodenode

responsible for authorization and authentication of content provider, responsible for authorization and authentication of content provider, charging, and overall data ﬂow through Core Network (CN)

charging, and overall data ﬂow through Core Network (CN)

In case of multicast, a request to join the session has to be sent to In case of multicast, a request to join the session has to be sent to become member of the corresponding MBMS service group

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Multimedia Broadcast/Multicast Service (MBMS)

MBMS data streams are not split until necessary MBMS data streams are not split until necessary

MBMS services are power limited and maximize the diversity MBMS services are power limited and maximize the diversity without relying on feedback from users

without relying on feedback from users

Two techniques are used to provide diversity: Two techniques are used to provide diversity:

Macro-diversity: combining transmission from multiple cells Macro-diversity: combining transmission from multiple cells

Soft combining: combines the soft bits received from the different Soft combining: combines the soft bits received from the different radio links prior to (Turbo) coding

radio links prior to (Turbo) coding Selec

Selection combinition combining: ng: decodidecoding ng the signal the signal receireceived from each ved from each cellcell individually, and for each TTI selects one (if any) of the correctly individually, and for each TTI selects one (if any) of the correctly decoded data blocks for further processing by higher layers

decoded data blocks for further processing by higher layers

Time-diversity: Time-diversity:

using a long TTI and application-level coding to combat fast fading using a long TTI and application-level coding to combat fast fading

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Multimedia Broadcast/Multicast Service (MBMS)

Streaming data are encapsulated in RTP and transported using Streaming data are encapsulated in RTP and transported using the FLUTE protocol when delivering over MBMS bearers

the FLUTE protocol when delivering over MBMS bearers

MAC layer maps and multiplexes the RLC-PDUs to the transport MAC layer maps and multiplexes the RLC-PDUs to the transport channel and selects the transport format depending on the

channel and selects the transport format depending on the instantaneous source rate

instantaneous source rate

MBMS uses the Multimedia Trafﬁc Channel (MTCH), which MBMS uses the Multimedia Trafﬁc Channel (MTCH), which

enables p-t-m distribution. This channel is mapped to the Forward enables p-t-m distribution. This channel is mapped to the Forward Access Channel (FACH), which is ﬁnally mapped to the

Access Channel (FACH), which is ﬁnally mapped to the

Secondary-Common Control Physical Channel (S-CCPCH) Secondary-Common Control Physical Channel (S-CCPCH)

The TTI is transport channel speciﬁc and can be selected from the The TTI is transport channel speciﬁc and can be selected from the set 10 ms, 20 ms, 40 ms, 80 ms for MBMS

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Multimedia Broadcast/Multicast Service (MBMS)

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LTE Evolved MBMS (eMBMS)

Will be defined in Release 9 of the 3GPP specifications Will be defined in Release 9 of the 3GPP specifications

currently in progress, expected to be frozen in Dec 2009 currently in progress, expected to be frozen in Dec 2009

Multimedia service can be provided by either:

Multimedia service can be provided by either: single-cell single-cell broadcast

broadcast oror multimulticell cell mode mode (aka(aka MBMS MBMS SinglSingle e FrequFrequencyency Network (MBSFN)

Network (MBSFN)))

In an MBSFN area, all eNBs are synchronized to perform In an MBSFN area, all eNBs are synchronized to perform

simulcast transmission from multiple cells (each cell transmitting simulcast transmission from multiple cells (each cell transmitting identical

identical wawavefveform)orm)

If user is close to a base station, delay of arrival between two cells If user is close to a base station, delay of arrival between two cells could be quite large, so the subcarrier spacing is reduced to 7.5 could be quite large, so the subcarrier spacing is reduced to 7.5 KHz and longer CP is used

KHz and longer CP is used

Main advantages over technologies such as DVB-H or DMB: Main advantages over technologies such as DVB-H or DMB:

no additional infrastructure no additional infrastructure

operator uses resources that are already purchased operator uses resources that are already purchased user interaction is possible

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MCE coordinates the synchronous multi-cell transmission MCE coordinates the synchronous multi-cell transmission The MCE can physically be part of the eNB

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L

LTE TE Deployment ConsiderationsDeployment Considerations

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LTE Deployment Considerations

Voice and SMS (main source of revenue for telecom companies) Voice and SMS (main source of revenue for telecom companies)

Circuit Switch Fallback (CS Fallback) Circuit Switch Fallback (CS Fallback) IMS-based VoIP

IMS-based VoIP

Voice over LTE via Generic Access (VoLGA) Voice over LTE via Generic Access (VoLGA)

Roaming revenues from current GSM networks (gone) Roaming revenues from current GSM networks (gone)

Interoperability with existing legacy technologies (including GSM, Interoperability with existing legacy technologies (including GSM, WCDMA, CDMA2000, WiMAX and others)

WCDMA, CDMA2000, WiMAX and others)

Leverage existing 3G capacity and coverage (make use of existing Leverage existing 3G capacity and coverage (make use of existing equipment)

equipment)

Service provision (not being a dumb bit pipe provider) Service provision (not being a dumb bit pipe provider) Security (especially EPC)

Security (especially EPC)

terminal devices (balancing battery life with MIMO support, and terminal devices (balancing battery life with MIMO support, and how much legacy support)

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Work Related to Video Streaming

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Mobile Video Transmission Using Scalable Video

Coding

Investigating per packet QoS would enable general packet Investigating per packet QoS would enable general packet

marking strategies (such as Differentiated Services). This can be marking strategies (such as Differentiated Services). This can be done by either:

done by either:

Mapping SVC priority information to Differentiated Services Code Mapping SVC priority information to Differentiated Services Code Point (DSCP) to introduce per packet QoS

Point (DSCP) to introduce per packet QoS

Making the scheduler media-aware (e.g. by including some Making the scheduler media-aware (e.g. by including some MANE-like functinality), and therefore able to use priority MANE-like functinality), and therefore able to use priority information in the SVC NAL unit header

information in the SVC NAL unit header

Many live-media distribution protocols are based on RTP, Many live-media distribution protocols are based on RTP,

including p-t-m transmission (e.g. DVB-H or MBMS). Provision of including p-t-m transmission (e.g. DVB-H or MBMS). Provision of different layers, on different multicast addresses for example,

different layers, on different multicast addresses for example, allows for applying protection strength on different layers

allows for applying protection strength on different layers

By providing signalling in the RTP payload header as well as in the By providing signalling in the RTP payload header as well as in the SDP session signalling, adaptation (for bitrate or device capability) SDP session signalling, adaptation (for bitrate or device capability) can be applied in the network by nodes typically known as MANE can be applied in the network by nodes typically known as MANE

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Work Related to Video Streaming

Downlink OFDM Scheduling and Resource Allocation

for Delay Constrained SVC Streaming

Problem Deﬁnition: Problem Deﬁnition:

Designing efficient multi-user video streaming protocols that fully Designing efficient multi-user video streaming protocols that fully exploit the resource allocation flexibility in OFDM and performance exploit the resource allocation flexibility in OFDM and performance scalabilities in SVC

scalabilities in SVC

Maximize average PSNR for all video users under a total downlink Maximize average PSNR for all video users under a total downlink transmission power constraint based on a stochastic

transmission power constraint based on a stochastic subgradient-based scheduling framework

subgradient-based scheduling framework

Authors generalize their previous downlink OFDM resource Authors generalize their previous downlink OFDM resource allocation algorithm for elastic data trafﬁc to real-time video allocation algorithm for elastic data trafﬁc to real-time video strea

streaming by ming by further further consconsidering dynamicidering dynamically ally adjuadjusted prioritysted priority weights based on the current video content, deadline

weights based on the current video content, deadline requirements, and the previous transmission results requirements, and the previous transmission results

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Scalable and Media Aware Adaptive Video Streaming

over Wireless Networks

A packet scheduling algorithm (in MANE) which operates on the A packet scheduling algorithm (in MANE) which operates on the different substreams of the main scalable video stream

different substreams of the main scalable video stream

Exploit SVC coding to provide a subset of hierarchically organized Exploit SVC coding to provide a subset of hierarchically organized substreams at the RLC layer entry point and utilize the scheduling substreams at the RLC layer entry point and utilize the scheduling algorithm to select scalable substreams to be transmitted to RCL algorithm to select scalable substreams to be transmitted to RCL layer depending on the channel transmission conditions

layer depending on the channel transmission conditions General idea:

General idea:

perform fair scheduling between scalable substreams until deadline perform fair scheduling between scalable substreams until deadline of oldest unsent data units with higher priorities is approaching

of oldest unsent data units with higher priorities is approaching do not maintain fairness if deadline is expected to be violated, do not maintain fairness if deadline is expected to be violated, packets with lower priorities are delayed in a ﬁrst time and later packets with lower priorities are delayed in a ﬁrst time and later dropped if necessary

dropped if necessary

In addition, SVC coding is tuned, leading to a generalized In addition, SVC coding is tuned, leading to a generalized

scalability scheme including regions of interest (ROI) (combining scalability scheme including regions of interest (ROI) (combining ROI coding with SNR and temporal scalability)

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Conclusions Conclusions

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Conclusions

LTE and SAE will be the uniﬁed 4G wireless network LTE and SAE will be the uniﬁed 4G wireless network

Backw

Backwards ards compatiblecompatible Multiple upgrade paths Multiple upgrade paths

Signiﬁcant carrier commitment Signiﬁcant carrier commitment

eMBMS seems promising for delivering multimedia content over eMBMS seems promising for delivering multimedia content over LTE (at least in theory) and without the need for a separate

LTE (at least in theory) and without the need for a separate infrastructure

infrastructure

LTE still faces some deployment challenges (but are currently LTE still faces some deployment challenges (but are currently being studied)

being studied)

Research interest in optimized streaming video via eMBMS Research interest in optimized streaming video via eMBMS

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(47)

[SSW’07]

T. Schierl, T. Stockhammer, and T. Wiegand,

T. Schierl, T. Stockhammer, and T. Wiegand, Mobile Video Mobile Video Transmission Using Scalable Video Coding

Transmission Using Scalable Video Coding , IEEE Transactions on, IEEE Transactions on Circuits and Systems for Video Technology, vol.17, no.9,

Circuits and Systems for Video Technology, vol.17, no.9, pp.1204-1217, Sept. 2007

pp.1204-1217, Sept. 2007 [JHC’08]

[JHC’08]

X. Ji, J. Huang, M. Chiang, G. Lafruit, and F. Catthoor,

X. Ji, J. Huang, M. Chiang, G. Lafruit, and F. Catthoor, Downlink Downlink OFDM Scheduling and Resource Allocation for Delay Constrained OFDM Scheduling and Resource Allocation for Delay Constrained SVC Streaming

SVC Streaming , IEEE International Conference on, IEEE International Conference on Communications (ICC’08), 2008

Communications (ICC’08), 2008 [TP’08]

[TP’08]

N. Tizon and B. Pesquet-Popescu,

N. Tizon and B. Pesquet-Popescu, Scalable and Media Aware Scalable and Media Aware Adaptive Video Streaming over Wireless Networks

Adaptive Video Streaming over Wireless Networks , EURASIP, EURASIP Journal on Advances in Signal Processing, 2008.