New Applications, Services and Features · BGCF. MGCF. MGW. PSTN/PLMN. o. Cellular Communication...

New Applications, Services and Features

• Voice over LTE (VoLTE) &• IP-based Multimedia Subsystem (IMS)

• Internet of Things (IoT)• Machine to Machine Communications (M2M)• Vehicle to Vehicle (V2V) and Vehicle to Everything (V2X) Comm.

• Other Services• Public Safety• Evolved Multimedia Broadcast/Multicast System (eMBMS)• Localization (for location-based services)

• Device-to-Device Communications (D2D)

VoLTE & IMS

Voice-over-LTE (VoLTE) Ingredients IP-based Multimedia Subsystem (IMS) Session Initiation Protocol (SIP) VoLTE Registration and Call Setup

Cellular Communication Systems 3Andreas Mitschele-Thiel, Jens Mueckenheim Nov. 2018

Voice over IP over Wireless – The Ingredients

User Plane for Forwarding and Processing of Voice Data Voice Codec generating IP packets on the IP side Transport protocol to transport VoIP packets IP-based network providing end-to-end service with required QoS wrt. delay,

delay jitter and error rate Proper scheduling of VoIP packets over wireless link Transcoder if VoIP is mapped on CS voice and transported over PSTN ...Control Plane for AAA, Call Handling, etc. Function/directory service that maps destination MSISDN number or other ID

on IP addresses Protocol that talks to directory server to do the MSISDN-IP mapping Protocol that ensures the setup and release of the needed resources, esp. in

entities where resources are scare, e.g. over the wireless link Some function that ensures proper charging of calls if not flat, e.g. abroad Some function to find location and to page mobile if not connected already Coordinate everything ...


Voice over IP over Wireless – The Ingredients => Translated to LTE

[1]

User Plane for Forwarding and Processing of Voice Data Voice Codec generating IP packets on the IP side Transport protocol to transport VoIP packets IP-based network providing end-to-end service with requiredQoS wrt. delay,

delay jitter and error rate Proper scheduling of VoIP packets over wireless link Transcoder if VoIP is mapped on CS voice and transported over PSTN ...Control Plane for AAA, Call Handling, etc. Function/directory service that maps destination MSISDN number or other ID

on IP addresses Protocol that talks to directory server to do the MSISDN-IP mapping Protocol that ensures the setup and release of the needed resources, esp. in

entities where resources are scare, e.g. over the wireless link Some function that ensures proper charging of calls if not flat, e.g. abroad Some function to find location and to page mobile if not connected already Coordinate everything ...

⇒ Client App (Skype, etc.)⇒ RTP⇒ QoS-enabled transport via

EPS bearers & beyond⇒ Semi-persistent scheduling⇒ Gateway to PSTN, e.g.

provided by Skype

⇒ SIP server

⇒ SIP protocol, SIP client⇒ QoS management for EPS

bearers & beyond⇒ 3GPP HSS & PCRF⇒ 3GPP Paging Function⇒ VoIP client/app


What does LTE/EPS provide for VoIP?

• EPS bearers with well defined QoS, i.e. QCI (latency, error rate) and GBR connecting the UE to a PDN

• Authentication, Authorization and Accounting for EPS bearers (HSS, PCRF)• Mobility management and paging of UEs with known IP addresses (HSS, MME)⇒ Basically provides an EPS bearer with well defined QoS to some external PDN

E-UTRAN

MME

Serving GW PDN GWS1-U

S1-MMES11

S5

InternetSGi

HSS

S6a

PCRF

GxGxc


Missing Parts

• VoIP client app for UE for • Voice sampling and encoding/decoding (codec)• Protocol for processing of real-time data and control of this (RTP, RTCP)• Bearer management to provide QoS enabled end-to-end transport• Client to setup and release calls, resolve numbers, negotiate codecs, etc.

(SIP client)• Directory service for VoIP users providing mapping of numbers/IDs to IP

addresses (SIP server)• QoS-enabled transport to connect UE to (network of) VoIP peer• Gateways (data and control) for calls to CS system (PSTN)

Missing parts could be implemented inside or outside of the operator-managed network• Outside: solutions like Skype, Facetime or WhatsApp without QoS and AAA

support from the LTE network => over-the-top VoIP solutions with separate authentication, may be some authorization and accounting, no QoS

• Inside: IMS, reusing AAA and QoS support of the LTE network => VoLTE


VoIP Application Client

• Client to setup and release calls, resolve numbers, negotiate codecs, etc. (SIP client)

• Bearer management to provide QoS enabled end-to-end transport (part of LTE)• Voice sampling and encoding/decoding (codec)• Protocol for processing of real-time data and control of this (RTP, RTCP)

E-UTRAN

MME


S1-MMES11

S5

InternetSGi

HSS

S6a

PCRF

GxGxc

Voice codec

RTP/RTCP

SIP client

LTE UE


IMS Directory Service and Session Control

Call Session Control Function (CSCF)• Mapping of user numbers/IDs to IP addresses (SIP server) of previously

registered users• Session control (setup, modification and release of voice call)

• Check authorization for service with HSS• Ensures proper QoS with PCRF

E-UTRAN

MME


S1-MMES11

S5 SGi

HSS

S6a

PCRF

GxGxc

Voice codec

RTP/RTCP

SIP client

LTE UE CSCF (SIP server)

Managed Internetwork


IMS Directory Service and Session Control

Some more issues:• Resolve number if called party is connected to another network • Handle calls if user is roaming in a foreign network

MME

Serving GW PDN GW

S11

S5 SGi

HSS

S6a

PCRF

GxGxc

S-CSCF

I-CSCF

P-CSCF

Proxy CSCF (P-CSCF) Initial point of contact in

visited network, forwards requests to resp. S-CSCF

Coordinates QoS of session Maintains security association

with UE Serving CSCF (S-CSCF)

SIP directory server Session control Located in home network

Interrogating CSCF (I-CSCF) Contact for calls from outside Routes requests to

responsible S-CSCF



IMS – Some More Functions

Some more issues:• Supplementary services• Interworking with CS networks

PDN GWSGi

HSS

PCRF

Gx

S-CSCF

I-CSCF

P-CSCF

Telefony Application Server (TAF) Provices supplementary

services, e.g. call forwarding, baring, conferencing

Media Resource Function (MRF) Media processing, e.g.

transcoding, conferencing, announcements, tones

Controlled by TAF and CSCF Media Gateway (MGW) and Media

Gateway Control (MGCF) Interworking with CS networks

Breakout Gateway Control Function (BGCF) Routing of SIP messages Determines network for CS

breakout


TAS

MRF

BGCF

MGCF

MGW

PSTN/PLMN

o


VoLTE: IMS Registration and Call Establishment Procedure – Overview

LTE Attach Setup of default EPS bearer to P-GW (as before, QCI 6-9, if IMS is not default

APN) Setup of default EPS bearer to IMS (QCI 5 for SIP signaling)

SIP/IMS registration over default EPS bearer to IMS

SIP signaling (over default EPS bearer to IMS) to establish MO/MT call over dedicated EPS bearer (QCI 1 for voice, QCI 2 for video call)

For details on call procedures see GSMA: VoLTE Service Description and Implementation Guidelines, Version 1.1, 26 March 2014 https://www.gsma.com/futurenetworks/wp-content/uploads/2014/05/FCM.01-v1.1.pdf

https://www.gsma.com/futurenetworks/wp-content/uploads/2014/05/FCM.01-v1.1.pdf


IMS Procedure – UE Attachment with IMS Default Bearer Establishment

Source: GSMA: VoLTE Service Description and Implementation Guidelines Version 1.1, 26 March 2014

o

• RRC Connection setup

• Signaling conn. setup withSM request

• Authentication/security• Update of HSS

• Setup of default EPS bearerfor IMS signaling (QCI 5) in EPS ...

• ... and E-UTRAN

• Bearer modification


IMS Procedure – IMS (SIP) Registration

Source: GSMA: VoLTE Service Description and Implementation Guidelines Version 1.1, 26 March 2014

o

SIP register at S-CSCF (connect user ID (MSISDN) to IP address)

ACK for SIP Register

Authentication messages (Diameter): AAR (AA Request), AAA (AA Answer), etc.See https://en.wikipedia.org/wiki/Diameter_(protocol) for details on diameter messages

Subscribe/Notify for extra services e.g. voice mail


SIP is a standard protocol for establishing voice calls over IP networks Set of standard commands to initiate, manage and terminate calls between

two SIP devices

SIP Session Setup and Release

[2]

Sources: www.netmanias.com and https://askozia.com/voip/what-is-sip/


Voice Call Establishment Through IMS & SIP – Simplified

*SDP - Session Description Protocol Source: www.netmanias.com


IMS Procedure – Voice Call Establishment (MO) Details

Source: GSMA: VoLTE Service Description and Implementation Guidelines Version 1.1, 26 March 2014o

SIP invite

Call setup details

Authentication

Authentication

EPS bearer establishment for voice call (QCI 1)


IMS Procedure – Voice Call Establishment (MT) Details

o

SIP invite

Call setup details

Authentication

Authentication

EPS bearer establishment for voice call (QCI 1)


VoLTE and IMS – Summary

IP-based Multimedia Subsystem (IMS) • a powerful solution to support Multimedia/QoS-enabled services and

applications as well as its control• a QoS-enabled transport network of its own• IMS is independent of LTE/EPS and works beyond specific networks• IMS for VoLTE comprises a subset of the functions of the full IMS, e.g. as

defined by GSMA • comprises an application/service layer, control/session layer and transport

layer• employs protocols standardized by IETF, e.g. SIP, Diameter, etc.

Session Initiation Protocol (SIP)• protocol to setup, maintain and release sessions possibly comprising multiple

connections in unicast or multicast manner

Real-time transport protocols (RTP, RTCP)• transport real-time data with clearly defined playout times and where

retransmission only makes sense if there is sufficient laxity


References

Session Initiation Protocol • Wikipedia: https://en.wikipedia.org/wiki/Session_Initiation_Protocol

IMS• Wikipedia: https://en.wikipedia.org/wiki/IP_Multimedia_Subsystem• 3GPP: IP Multimedia Subsystem (IMS), Stage 2: TS 23.228• S. Scalisi: IMS Release 10 Tutorial,

http://disi.unitn.it/locigno/didattica/AdNet/10-11/IMS_Tutorial_Scalisi.pdf

Call Processing in VoLTE-enabled IMS• GSMA: VoLTE Service Description and Implementation Guidelines Version

1.1, 26 March 2014, https://www.gsma.com/futurenetworks/wp-content/uploads/2014/05/FCM.01-v1.1.pdf

• Netmanias: What happens when a user performs a voice call from an LTE/4G network? – VoLTE, https://www.netmanias.com/en/post/blog/10907/lte-volte/part-3-what-happens-when-a-user-performs-a-voice-call-from-an-lte-4g-network-volte

• Videos on IMS and Procedures see http://telecomtutorial.info/volte-sip-ims-registration-call-flow-procedure/

https://en.wikipedia.org/wiki/Session_Initiation_Protocol

https://en.wikipedia.org/wiki/IP_Multimedia_Subsystem

http://disi.unitn.it/locigno/didattica/AdNet/10-11/IMS_Tutorial_Scalisi.pdf

https://www.gsma.com/futurenetworks/wp-content/uploads/2014/05/FCM.01-v1.1.pdf

https://www.netmanias.com/en/post/blog/10907/lte-volte/part-3-what-happens-when-a-user-performs-a-voice-call-from-an-lte-4g-network-volte

Internet of Things (IoT)

Definitions and Requirements for IoT & MTC NB-IoT in LTE Power Saving Mode (PSM) Extended Discontinuous Reception (eDRX) V2V & V2X


Internet of Things (IoT)

Definition by the ITU, 2012:A global infrastructure for the information society, enabling advanced services by interconnecting (physical and virtual) things based on existing and evolving interoperable information and communication technologies.

Source: ITU: Overview of the Internet of Things, Recommendation ITU-T Y.2060, 2012 https://www.itu.int/ITU-T/recommendations/rec.aspx?rec=11559&lang=en

Definition by the GSMA, 2017:A generic term for the network of physical objects that contain embeddedtechnology to communicate and sense or interact with their internal states orthe external environment. IoT offers functions and services which go beyondthe scope of M2M.

Source: GSMA: NB-IoT Deployment Guide to Basic Feature set Requirements, White Paper CLP.28 – V. 1.0, August 2017 https://www.gsma.com/newsroom/wp-content/uploads/CLP.28v1.0.pdf

Definition by Guillemin and Friess, 2009: The Internet of Things allows people and things to be connected Anytime, Anyplace, with Anything and Anyone, ideally using Any path/network and Any service.

https://www.itu.int/ITU-T/recommendations/rec.aspx?rec=11559&lang=en

https://www.gsma.com/newsroom/wp-content/uploads/CLP.28v1.0.pdf


IoT Applications and Requirements

Applications- supply-chain management, logistics, automotive - healthcare, smart building, smart home, entertainment- agriculture, environmental monitoring, disaster alerting

IoT – (Diverse) requirements and challenges for mobile networks- Large number of devices- Low energy consumption- Always connected - Large amount of data- Fast processing and response time- High reliability- Context awareness- Privacy and securityBut: actual requirements highly depend on the specific application!⇒ Better to distinct between MTC, V2V/V2X and sensor/metering devices


Machine-Type (MTC)/Machine-to-Machine (M2M) Communication

• Large variety of M2M applications already in use• Stationary applications: metering of consumption data, environment

monitoring, telemedicine, telemonitoring• Mobile M2M applications: tracking of goods (logistics), autonomous

communication between vehicles (V2X)• Communication over cellular systems

• In parts of the world (nearly) complete coverage

• Low cost connection to even hardly accessible locations

• Often in 2G systems, 3G/4G upcoming• Challenges for cellular M2M communication

• Occurrence of variable radio conditions• Times with bad or no radio link• Small data reports but for a high number

of M2M devices• 3GPP provides various LTE improvements

under MTC and IoT enhancements


Machine-Type Communications (MTC) in LTE (Release 12 & 13)

• MTC in Release 12, enhanced MTC (eMTC) in release 13• In-band LTE operation• Reduced data rate and bandwidth (narrow-band)

• 1,08 MHz band (6 PRBs/timeslot)• simplified PHY

• 1 Mbps for DL and UL• Reduced broadcast information• Extended DRX cycles for

• RRC idle (up to 3 hrs) and• RRC connected mode (up to 10 sec)

• Power Saving Mode (PSM) for even longer periods• Optimized protocols

• Simplified PDCP, RLC AM only• simplified HARQ process

• ...

For details seehttp://www.3gpp.org/images/presentations/3GPP_Standards_for_IoT.pdf

http://www.3gpp.org/images/presentations/3GPP_Standards_for_IoT.pdf


IoT in 3GPP Context – Narrowband IoT (NB-IoT), Release 13

Definition by the GSMA:Narrowband IoT (NB-IoT) is a new 3GPP radio technology standard that addresses the requirements of the Internet of Things (IoT). The technology provides

• improved indoor coverage, • support of massive number of low throughput devices, • low delay sensitivity, • ultra-low device cost, • low device power consumption and • optimized network architecture.

The technology can be deployed “in-band”, utilizing resource blocks within a normal LTE carrier, or in the unused resource blocks within a LTE carrier’s guard-band, or “standalone” for deployments in dedicated spectrum.

Source: GSMA: NB-IoT Deployment Guide to Basic Feature set Requirements, White Paper CLP.28 – V. 1.0, August 2017 https://www.gsma.com/newsroom/wp-content/uploads/CLP.28v1.0.pdf

For details on IoT in 3GPP context see http://www.3gpp.org/news-events/3gpp-news/1766-iot_progress and http://www.3gpp.org/images/presentations/3GPP_Standards_for_IoT.pdf

https://www.gsma.com/newsroom/wp-content/uploads/CLP.28v1.0.pdf

http://www.3gpp.org/news-events/3gpp-news/1766-iot_progress

http://www.3gpp.org/images/presentations/3GPP_Standards_for_IoT.pdf


NB-IoT in LTE (Release 13)

• New radio for low end market• Reduced data rate and bandwidth

• 180kHz band (single PRB/timeslot)• 3 modes of operation

• Stand-alone carrier, guard band LTE transmission &• In-band LTE

• simplified PHY • SC-FDMA (250 kbps) & single-tone use (20 kbps)• New set of physical channels

• Reduced broadcast information• Extended DRX cycles for RRC idle (up to 3 hrs) and RRC connected mode (up

to 10 sec)• Power Saving Mode (PSM) with sleep times up to 413 days• Reduced mobility support• Optimized protocols

• Simplified PDCP, RLC AM only• Single HARQ process only

• Simplified architecture: C-SGN combines MME, S-GW & P-GW


Power Saving Mode (PSM), Release 12

• Supports application-specific, UE-provided sleep cycles with no RX and TX activities up to 413 days

• No TA Update during sleep cycle• No UE Reattach after sleep cycle due to network awareness of PSM• Reaching time up to 186 minutes after sleep cycle• Simple activation of PSM with TA Update• Possible buffering of DL packets in network during UE sleep cycle• Available for all LTE UEs

See TS 23.682 and TS 24.301 for details

Source: GSMA: NB-IoT Deployment Guide to Basic Feature set Requirements, White Paper CLP.28 – V. 1.0, August 2017


Extended Discontinuous Reception (eDRX)

• Focus on optimization for mobile-terminated traffic• Extension of DRX (switch of receiver for a fraction of a second)• eDRX applies to RRC-idle (extended paging cycle) and RRC-connected state• eDRX cycle times are negotiated between UE and network• eDRX cylcles range from 10 sec to 3 hours• Network buffers DL packets during sleep time• Used in conjunction with PSM or without PSM to save energy in UE

See TS 23.682 and TS 24.301 for details

Source: GSMA: NB-IoT Deployment Guide to Basic Feature setRequirements, White Paper CLP.28 – V. 1.0, August 2017


Vehicle to Vehicle (V2V) und Vehicle to Everything (V2X)

Application support• V2V: broadcast to surrounding devices informing about traffic dynamics,

location, vehicles attributes, etc.• V2I (V2Infrastructure): communication towards Road Side Unit (RSU)

and local application server, to be forwarded to UEs in broadcast, multicast or unicast mode

• V2P (V2Pedestrian): provision of warnings to pedestrians with low battery capacity and low radio sensitivity

• V2N (V2Network): communication with the EPS

Source: Xuyu Wang, Shiwen Mao, andMichelle X. Gong. 2017. An Overview of 3GPP Cellular Vehicle-to-Everything Standards. GetMobile: Mobile Comp. and Comm. 21, 3 (November 2017), 19-25.


Vehicle to Vehicle (V2V) und Vehicle to Everything (V2X)

Issues• Low latency and high reliability (safety) requirements• Direct communication with geographical neighbors• High relative speed between mobiles resulting in Doppler shift• Possibly high density of devices

Measures for V2X support in LTE Release 12 & onwards• Sidelink: Device-To-Device (D2D) communication• Proximity Service: discovery of surrounding devices• Additional DMRSs (reference symbols): retrieve data in presence of Doppler

shift up to relative speed of 500 km/h• Modified scheduling for high user density and low latency requirements• Resource scheduling schemes for D2D:

• centralized – eNB-based grant provisioning• distributed/random by D2D UEs

Enhanced V2X (eV2X) Services• Vehicle Platooning• Advanced Driving (semi- or fully-automated driving, coordinated maneuvers

and trajectories, traffic safety and efficiency)• Extended Sensors (use of sensors from surrounding vehicles or pedestrians)• Remote Driving


Extensions of Standardized Quality Class Identifiers (QCI)

QCI ResourceType Priority

Packet Delay

Budget

Packet Error

Loss R.Example Services

1 GBR 2 100ms 10−2 Conversational Voice 2 GBR 4 150ms 10−3 Conversational Video (Live Streaming) 3 GBR 3 50ms 10−3 Real Time Gaming, V2X messages 4 GBR 5 300ms 10−6 Non-Conversational Video (Buffered Streaming) 65 GBR 0.7 75ms 10−2 Mission Critical user plane Push To Talk voice (e.g., MCPTT) 66 GBR 2 100ms 10−2 Non-Mission-Critical user plane Push To Talk voice67 GBR 2 100ms 10−2 Mission Critical Video user plane75 GBR 2.5 50ms 10−2 V2X messages5 non-GBR 1 100ms 10−6 IMS Signalling

6 non-GBR 6 300ms 10−6 Video (Buffered Streaming) TCP-Based (for example, www, email, chat, ftp, p2p and the like)

7 non-GBR 7 100ms 10−3 Voice, Video (Live Streaming), Interactive Gaming

8 non-GBR 8 300ms 10−6 Video (Buffered Streaming) TCP-Based (for example, www, email, chat, ftp, p2p and the like)

9 non-GBR 9 300ms 10−6 Video (Buffered Streaming) TCP-Based (for example, www, email, chat, ftp, p2p and the like). Typically used as default bearer

69 non-GBR 0.5 60ms 10−6 Mission Critical delay sensitive signalling (e.g., MC-PTT signalling) 70 non-GBR 5.5 200ms 10−6 Mission Critical Data (e.g. example services are the same as QCI 6/8/9) 79 non-GBR 6.5 50ms 10−2 V2X messages80 non-GBR 6.8 10ms 10−6 Low latency eMBB applications; augmented reality82 GBR 1.9 10ms 10−4 Discrete Automation, max. burst size 255 bytes83 GBR 2.2 10ms 10−4 Discrete Automation, max. burst size 1358 bytes84 GBR 2.4 30ms 10−5 Intelligent Transport Systems, max. burst size 1358 bytes85 GBR 2.1 5ms 10−5 Electricity distribution, max. burst size 255 bytes

See TS 23.203 for newest version

Other Services

Public Safety Communications

Evolved Multimedia Broadcast Multicast Services (eMBMS)

Localization of UEs


Public Safety Communications (Release 9, 11+)

Communication services for public safety community, i.e. police, emergency services, firefighters, homeland security, public transportation systems, etc.

Focus:• Public Warning System (PWS): text-based messaging (Rel. 9)• Proximity Services: neighbor discovery for public safety applications (groups)

Group communications and management: Mission-Critical Push To Talk, Videos, Data)

• D2D communications without LTE infrastructure available• Multimedia Broadcast Supplements for Public Warning System (MBSP):

distribution of maps, images of missing persons, evacuation information, weather warnings, shelter locations, assembly points, etc.


Mission Critical Communications (MCC)

Issues• Public safety agencies traditionally use narrow band radio networks such as

TETRA (Terrestrial Trunked Radio):• Provide functionalities like D2D, group management, floor control, etc.• But suffer from low spectral efficiency, limited data transport capabilities, slow

evolution and high costs due to lack of economies of scale

• Supplement their voice communications through private networks with carrier network voice and mobile broadband data

• Cost effective, coverage advantages, removes interconnectivity

Mission Critical Services:• Mission Critical Push To Talk (MCPTT) targeting police, fire brigade,

ambulance, etc.• Mission Critical Video (Remote monitoring, Push to Video for first responders

to share the real conditions)• Mission Critical Data (Control of operations, computer aided dispatch,

database enquiries, intelligence gathering, etc.)• Incredients

• Group Call System Enablers (GCSE): support for efficient and dynamic group communication, e.g. one-to-many calls and broadcasts

• Proximity Services (ProSe): discover relevant devices in close physical proximity and enable optimized communications between them


Evolved Multimedia Broadcast Multicast Services (eMBMS), Rel. 9, 11

Rational: • Mobile radio is a broadcast medium by nature• Broadcasts allow the same content to be provided to several people in the

same cell or area by a single transmission instead of multiple one-to-one connections

Applications: Mobile TV, radio broadcasts, live streaming, video services, file deliveries, emergency alerts

Issues:• Works in RRC-idle and RRC-connected mode• Synchronization among eNBs needed (single frequency network)• DL only, no individual feedback or retransmission mechanism• Tradeoff between several individually optimized transmissions and cell- or

even system-wide broadcast


eMBMS

• eMBMS shall provide similar services to LTE than MBMS in UMTS• Broadcast: all users can access not encrypted data• Multicast: only registered users can access the encrypted data

• MBMS supports (simultaneous) transmission of different content• Audio and/or video streaming• Audio and/or video download• File download, e.g. for software updates• Image and text distributions

• Separate MBMS logical, transport and physical channels:• Logical channels: MCCH/MTCH• Transport channel: MCH• Physical channel: PMCH

• Multicast/Broadcast on a Single Frequency Network (MBSFN) implementation:• Same data is sent from multiple eNBs on the same time-frequency

resources• Extended cyclic prefix to combate higher delay spread• Reduced subcarrier bandwidth (7.5 kHz instead of 15 kHz) for dedicated

mode (carrier solely used for eMBMS) to support large cells


eMBMS Architecture

MBMS GW

eNB

MCE

|

|

M1

M3 MBMS GW: MBMS GatewayMCE: Multi-Cell/Multicast Coordination Entity

M1: user plane interfaceM2: E-UTRAN internal control plane interfaceM3: control plane interface between E-UTRAN and EPC

MME

|M2

• MBMS GW: sending/broadcasting of MBMS packets to each eNB transmitting the service• Use of IP multicast

• Multi-Cell/Multicast Coordination Entity (MCE): • admission control • allocation of radio resources used by all

eNBs in the MBSFN area

For details see 3GPP TS 36.300: E-UTRA & E-UTRAN, Overall description, stage 2, chapter 5


Localization of UEs

• Location-based services (services requiring the location of the UE):• emergency calls• area-event triggers• infotainment• advertisements

• Localization methods: • Satellite-based (UE-based)

• (Assisted) Global Navigation Satellite Systems (A-GNSS)• Mobile Radio-based (UE-based or eNB-based)

• Enhanced cell ID (eCID)• Timing advance, Round-Trip Time, Angle of Arrival

• Observed Time Difference of Arrival (OTDOA)• Hybrid methods


Protocols to Support UE Localization and Information Reporting

• LTE Positioning Protocol (LPP) – control plane• LPP exchanges positioning information between UE and Serving Mobile

Location Center (SMLC) • Reliable and robust control plane connection for emergency scenarios

• Secure User-Plane Location (SUPL)/LPP – user plane• Secure data transmission between UE and network via user plane• Default approach for infotainment (map services, advertising, find a

friend, etc.)

LCS: Location ServiceE-SMLC: Evolved Serving Mobile Location CenterGMLC: Gateway Mobile Location CenterSLP: SUPL Location Platform


Localization Methods: Observed Time Difference of Arrival (OTDOA)

• Applied where there are insufficient GNSS signals• Lack of line of sight, e.g. urban or indoor areas

• TDOA estimates position of target based on measuring time difference from at least three eNBs

• Position of target is the intersection of three hyperbolas


Localization Methods: Enhanced Cell ID (eCID)

UE reports for each received cell• Cell ID• RSRP (received power)• RSRQ (received quality – SNR) Additional info for serving cell:• Rx-Tx time difference• possibly ancle of arrival

• Applied where there are insufficient GNSS signals

• eCID is based on cell of origin (COO)• derivation of serving cell executing

tracking area update or by paging• 3 cases/types of measurements

1: Estimate distance from a single BS2: Measuring the distance from 3 BSs3: Measuring the angle of arrival (AoA) fromat least 2 BSs

Device-to-Device (D2D) Communication

Idea and Benefits of D2D

ProSe Architecture and Functions

Mode Selection

Sidelink Communication

Radio Resource AllocationSources: Xingqin Lin, Jeffrey G. Andrews, Amitabha Ghosh, and Rapeepat Ratasuk: An overview of 3GPP

device-to-device proximity services, IEEE Communications Magazine, April 2014 3GPP TS 23.303 V15.1.0: Proximity-based services (ProSe), Stage2 3GPP TR 22.803 (Rel. 12): Feasibility Study for Proximity-based Services (ProSe) 3GPP TR 23.703 (Rel. 12): Study on Architecture Enhancements to Support Proximity Services (ProSe) 3GPP TR 36.843 (Rel. 12): Study on LTE Device to Device Proximity Services; Radio Aspects


Idea and Benefits of D2D Communication

Idea: devices in proximity communicate directly with or without network control using licensed or unlicensed bands

Benefits of D2D Proximity gain:

latency power data rate error rate (reliability) spectral efficiency

Offload cellular networks Coverage expansion beyond cellular infrastructure

Spectrum Unlicensed (out-band) D2D, i.e. Bluetooth, ZigBee, WiFi-Direct, LTE-U Licensed (in-band) D2D, using LTE sidelink


in-coverage scenario partial coverage scenario out-of-coverage scenario

D2D Scenarios

Control & Data

Cellular communication eNB-controlled D2D D2D without network control


Idea: Discovery of relevant UEs in proximity, independent of used radio technology, subscribed PLMN (roaming), etc., and preparing for direct communication (in any radio technology) between with them

Applications: location-based services, public safety

Proximity Services (ProSe) Architecture

UE UE

ProSeFunction

HSS

ProSeApplication

Server

ProSeApplication

ProSeApplication

Sidelink

Source: TS 23.303 (simplified)

E-UTRAN

ProSe Application server Database for application-specific information

ProSe Function EPC-level discovery

Discovery of candidates for D2D using location information in the EPC

Maintenance of ProSe-related subscriber data Direct ProSe discovery

Direct discovery of D2D entities (with support from the EPC)

Direct communication Setup of sidelink communication providing

needed information to UEs Charging and security


Discovery: devices repeatedly broadcast short message codes to be directly detected by other devices in vicinity ProSe function used to decode message codes Messages can be for advertisement of services or request for information

Two types of discovery Open: no explicit permission required from UEs being discovered Restricted: explicit permissions needed from UEs being discovered

Two modes resource assignment for discovery Type 1: devices distributedly select resources from pre-configured resource

pools for discovery transmission Type 2: network explicitly assigns resources for discovery transmission via

RRC signaling

Discovery models: Proactive mode: announcing (beacons) & monitoring Reactive mode: request for information (discoverer UE) & responding

(discoveree UE)

ProSe Direct Discovery


Sidelink: direct radio link between devices (UEs) exchanging data Analogous to uplink (UL) & downlink (DL) in cellular networks Standardized to use UL spectrum of cellular networks

Due to smaller load in UL & simpler receiver design

Sidelink connectivity: possible for in-coverage & out-of-coverage scenarios Configurations define set of resources for sidelink transmission & reception

In-coverage: configurations provided via cell system information using dedicated RRC signalling

Out-of-coverage: pre-configured setting in devices

Modes of sidelink communication Mode 1: network explicitly assigns resources via scheduling grant (SG) Mode 2: devices autonomously selects resources from pre-configurations

Sidelink synchronization Provides timing reference for sidelink transmission and/or reception In-coverage: devices use network’s cell synchronization signals Out-of-coverage: devices transmit special sidelink synchronization signals (SLSS)

Sidelink Communication (LTE inband)

Source on Sidelink: • Dahlman, E., Parkvall, S., & Skold, J. (2016). 4G, LTE-advanced Pro and the Road to 5G. Academic Press.• 3GPP TR36.843 LTE D2D Proximity Services Radio Aspects


Issue: decide for D2D or D2I mode based on some optimization criteria

Strategies: UE-based: UEs discover and select each other Network-assisted: mode selection made by eNB based on predefined

criteria

Possible selection criteria: spectral efficiency low latency low transmit power spectrum reuse …

Mode Selection: cellular or D2D

Source on Mode selection: TS 36.331, V15.3.0: RRC protocol specification


Two major radio resource allocation schemes Orthogonal resources (single user per PRB per cell): disjunct from

resources for D2I Non-orthogonal/shared resources (multiple user per PRB per cell): reuse

of resources for D2I and possibly other D2D pairs

Radio Resource Allocation for D2D

eNB

DUETx

DUERx

RB1

D2D1

CUETx

DUETx

DUERx

RBn

D2Dn

DUERxDUETx

RB2

D2D2

RB3

eNBCUETx

DUETx

DUERx

RB1

D2Dn

RB1

DUETx

DUERx

RB1

D2D1

DUERxDUETx

RB1

D2D2

orthogonal resources shared resources


Radio Resource Allocation for D2D

Orthogonal resources Overlay D2D Orthogonal resources assigned to cellular & D2D

Nonorthogonal/shared resources Underlay D2D Simultaneously reuse of all resources for D2I and (multiple) D2D users Increase of intra-cell interference for cellular user and possibly other D2D users

(kind of network densification)

Nonorthogonal/shared

Orthogonal


Interference Situation with Reuse of UL Resource

• D2D communication to use Uplink(UL) spectrum

• Uplink (UL) spectrum reuseo DTs degrade SINR at BS (red

dotted line)o CTs degrade SINR at DUE

receivers (purple dotted line)o DTs mutual interference degrades

their SINRs (blue dotted line)

• Interference mitigation is requiredfor reliable communicationo Radio resource allocation & power

control schemesBS: Base StationCTTx: Cellular Terminal TransmitterDTTx/Rx: D2D Terminal Transmitter/ReceiverPC/D: Transmit power of CT/DTIC/D/D2D: Interference signal from CT/DTSINRI: Signal to Interference plus noise ratio at BSSINRD: Signal to Interference plus noise ratio at DTRx

BS

DTTx-1

CTTxID

PC

SINRI

DTRx-1

IC

PD-1SINRD-1

DTRx-2

ICPD-2

SINRD-2

DTTx-2

ID ID2D

New Applications, Services and Features · BGCF. MGCF. MGW. PSTN/PLMN. o. Cellular Communication...

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Transcript of New Applications, Services and Features · BGCF. MGCF. MGW. PSTN/PLMN. o. Cellular Communication...