MLINARSKY Considerations for PS LTE architecture 10929 – Handset and network architecture for a PS LTE MC ... Network 3GPP Non-LTE Access: GPRS, UMTS, ... Issue with conventional

NPSTC is a federation of organizations whose mission is to improve!public safety communications and interoperability through collaborative leadership.!

Authors: Fanny Mlinarsky, octoScope, [email protected]

Dr. Ming Lai, Telcordia, [email protected] Jose Graziani, octoScope, [email protected]

29-Sep-11

NPSTC is a federation of organizations whose mission is to improve public safety communications and interoperability through collaborative leadership.! 2

•  Project summary –  Handset and network architecture for a PS LTE MC Voice service –  IMS-based LTE voice service –  Talkaround mode based on 802.11s mesh architecture with patent-pending ivMesh

technology to solve some of the issues with mobile mesh –  IMS-EPC testbed for testing the IMS based handset client –  PTT over partner LMR radio –  Connection Manager

MC = mission critical IMS = IP multimedia subsystem PTT = push to talk LTE = long term evolutions PS = public safety EPC = evolved packet core LMR = land mobile radio


•  Push to talk (< 500 ms connection time) •  Low latency (< 100 ms) •  Talkaround mode of operation •  Priority access with or without pre-emption •  Guaranteed voice message delivery •  Security with encryption •  Simultaneous voice and data (e.g. seeing

location of callers when talking) •  VoIP recording •  Voice service roaming and interworking with

private public safety networks and commercial cellular networks

Talkaround mesh LTE infrastructure


•  IMS based LTE network architecture to support voice, data, video, PTT, QoS

•  Interworking function to interconnect legacy handsets, including P25 and analog radios, to the PS LTE network

•  Seamless mobility among islands of PS LTE coverage interconnected via commercial 2G/3G and LTE networks

•  Talkaround mode of operation using patent-pending ivMeshTM technology (802.11s with layer 2 distributed voice protocol)

•  Call manager function in the handset to switch operating modes

–  Infrastructure PS LTE –  Infrastructure 2G/3G and LTE via commercial cellular radio –  Talkaround QoS = quality of service

ivMesh = isochronous voice mesh

Handset to incorporate LTE, 2G/3G and Wi-Fi radios, based on off-the-shelf hardware

Interoperability with legacy radios ensured by the infrastructure Interworking function


•  Open source platform, such as Android with off the shelf radio modules •  Patent-pending ivMeshTM layer 2 voice technology seamlessly rides on the ‘heart beat’ of an

802.11s network •  Optional VHF front end for longer range – White Spaces [5] or 900 MHz band (Note: We

would prefer to use the licensed 700 MHz band but FCC disallows transmissions other than LTE Release 8 in this band, per FCC Order 10-79 issued May 12, 2010)

ivMesh = isochronous voice mesh PoC = PTT over cellular VHF = very high frequency

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PS Interworking function enables

interoperability with legacy handsets;

supports P25 ISSI, QoS, roaming

among PS LTE networks, etc.

eNB

HSS

Non-3GPP Access: WiMAX, WiFi, EVDO, …

LTE Radio Access

Inter-operator NNI

AAA

PCRF

700 MHz Broadband Public Safety Network (BPSN)

Gateway: PSAP,

Roaming, CMAS,

LI, Media, Signal

Session Control (IMS )

Push to Talk (PTT)

LBS MBS MPS

Session Continuity (VCC)

3 GPP Evolved Packet Core (EPC)

IP Network

Project 25 & Other LMR

Systems Other Public Safety Apps.

Roaming Exchange

PS Voice IWK Function

Android Handset With PS Voice App.

Other LTE Wireless Network

3GPP Non-LTE Access: GPRS, UMTS, HSPA, ….

ISSI = Inter-RF Subsystem Interface


•  The PS community needs a certification standard for PS handsets similar to GCF and PTCRB

–  GCF is responsible for LTE conformance testing with the focus on European operators; PTCRB provides certification for North American operators

•  PS certification has unique certification requirements, for example: –  PTT-specific certification with the focus on priority and

preemption features – infrastructure and talkaround modes –  Seamless roaming and VCC among islands of PS LTE

networks and commercial 2G/3G/LTE networks –  PS security related certification –  Call management and VCC between infrastructure and

talkaround modes, OTA provisioning and other such operational functionality

•  Coordinate with PSCR UE Testing Study group

PTCRB = PCS Type Certification Review Board PCS = Personal Communications System, GCF = Global Certification Forum VCC = voice call continuity PSCR = public safety communications research UE = user equipment

www.globalcertificationforum.org

www.ptcrb.com

PS IMS-EPC-LTE testbed to be developed for this project may be useful to the PSCR community


Issue with conventional 802.11s network ivMesh solution The ongoing process of self-healing and self-forming of a mesh with mobile mesh nodes could result in bursts of dropped voice packets and thus degrade voice quality.

Collaborative packet recovery whereby each node can request from other nodes voice packets missing from its RX queue

The ongoing process of self-healing and self-forming of a mesh with mobile mesh nodes could result in excessive traffic used by conventional routing algorithms to rebuild routing tables following each topology change

Zero-noise routing protocol whereby path discovery information is inserted into voice packets thus eliminating special path discovery traffic and freeing the airlink bandwidth for voice packet recovery

Unpredictable and variable delays inherent to the mesh topology could degrade voice quality.

Protocol layer reduction whereby voice-specific layer 2 functionality can expediently forward packets through the mesh at the highest priority and quickly recover routing tables after self-healing; use of receive buffers for elimination of jitter that results from irregular delays through mesh network


•  Voice packet stream is a series of short packets (100-200 usec, depending on the CODEC) separated by gaps on the order of 20 msec. To optimize voice quality, packets need to be recovered at the receiver at regular intervals (i.e. isochronously).

•  ITU has defined voice quality standards with R-Factor being commonly used as a VoIP metric

Delay, jitter (packet to packet delay variation through the network) and packet loss result in degraded voice quality.


Parameter Abbr. Unit Default Value Permitted Range Send Loudness Rating SLR dB +8 0 … +18 Receive Loudness Rating RLR dB +2 -5 … +14 Sidetone Masking Rating STMR dB 15 10 … 20 Listener Sidetone Rating LSTR dB 18 13 … 23 D-Value of Telephone, Send Side Ds - 3 -3 … +3 D-Value of Telephone Receive Side Dr - 3 -3 … +3 Talker Echo Loudness Rating TELR dB 65 5 …65 Weighted Echo Path Loss WEPL dB 110 5 ... 110 Mean one-way Delay of the Echo Path T ms 0 0 … 500 Round-Trip Delay in a 4-wire Loop Tr ms 0 0 … 1000 Absolute Delay in echo-free Connections Ta ms 0 0 … 500 Number of Quantization Distortion Units qdu - 1 1 … 14 Equipment Impairment Factor Ie - 0 0 … 40 Packet-loss Robustness Factor Bpl - 1 1 … 40 Random Packet-loss Probability Ppl % 0 0 … 20 Circuit Noise referred to 0 dBr-point Nc dBmOp -70 -80 … -40 Noise Floor at the Receive Side Nfor dBmp -64 - Room Noise at the Send Side Ps dB(A) 35 35 … 85 Room Noise at the Receive Side Pr dB(A) 35 35 … 85 Advantage Factor A - 0 0 … 20


•  MOS (mean opinion score) uses a wide range of human subjects to provide a subjective quality score (ITU-T P.800); E-Model computes Rating Factor or R-Factor as a function of delay, packet loss and other variables (ITU-T G.107)

MOS

R

Excellent 5

Good 4

Fair 3

Poor 2

Bad 1 0 20 40 60 80 100


•  3GPP proposal for a study on Proximity-based Services at 3GPP SA1 –  ftp://ftp.3gpp.org/TSG_SA/TSG_SA/TSGS_53/Docs/SP-110638.zip –  Direct UE to UE mode of operation

•  Work appears to have started more than 10 years ago; championed by Qualcomm •  Not clear how this would work in an FDD LTE network with radios having UL/DL at

different frequencies and thus being unable to communicate with one another; –  Will likely require TDD

•  Not clear whether this will involve 2 devices or a mesh of devices •  Justification: “Proximity-based applications and services represent a recent and

enormous socio-technological trend. The principle of these applications is to discover instances of the applications running in devices that are within proximity of each other, and ultimately also exchange application-related data. In parallel, there is interest in proximity-based discovery and communications in the public safety community…”

FDD = frequency division duplexing TDD = time division duplexing UE = user equipment UL = uplink DL = downlink


•  PTT over ivMesh for talkaround –  Prototype ivMesh layer 2 based voice solution for talkaround mode –  Integrate PTT over ivMesh

•  PTT over IMS –  Prototype PTT software over IMS and test it against the IMS/EPC testbed based on

FOKUS [6] IMS-EPC testbed •  Develop and test key components of Connection Manager •  Integrate PTT/ivMesh, PTT/IMS, PTT/LMR and Connection Manager client

software into a partner LMR radio and test operation using actual radios



•  Open 802.11s –  http://open80211s.org/ –  Integrated in Linux kernel as of 2.6.26 –  Atheros support for 5xxx chips in 2.6.29 (legacy 11g/a) –  Atheros support for 9xxx (11g/a/n) –  BATMAN support added in 2.6.33 –  www.open-mesh.org

•  Ad-hoc routing protocols –  http://en.wikipedia.org/wiki/Ad_hoc_routing_protocol_list

•  IETF Mobile Ad-hoc Networks (MANET) –  http://datatracker.ietf.org/wg/manet/charter/


•  HWMP (802.11s default) –  Based on AODV routing (RFC 3561) –  Used in MANETs

•  802.11s allows for alternative and flexible implementations of path selection protocols and metrics. –  RA-OLSR used to be an alternative in the earlier 802.11s drafts

•  Babel –  Based on OLSR –  Distance-vector routing protocol (RFC 6126); loop avoiding –  Open source: http://www.pps.jussieu.fr/~jch/software/babel/; stand-alone application - not part

of the Linux kernel; not limited to wireless networks •  BATMAN Advanced

–  Layer 2 –  Open source: http://www.open-mesh.org/

HWMP = hybrid wireless mesh protocol AODV = Ad hoc On-Demand Distance Vector MANET = mobile ad hoc networking BATMAN = better approach to mobile ad-hoc networking OLSR = optimized link state routing RA-OLSR = radio aware OLSR


•  Select the VoIP client most appropriate for our application. Examine the following candidate solutions:

–  NIST SIP Communicator is an open source VoIP (IMS/SIP) client currently used in the Telcordia IMS testbed (figure 4) and has been found to be very robust. It is currently available for Windows, Linux and MAC (http://www.voip-info.org/wiki/view/Open+Source+VOIP+Software). The Android version is still under development (http://www.sip-communicator.org/index.php/Documentation/FAQ), but may be ready by the time we begin our prototyping effort.

–  SipDroid is an Android open source VoIP client implementation that is designed to work over Wi-Fi (http://www.onsip.com/onsip-team-reviews/voip/sip-clients-for-mobile/sipdroid). There is a known security issue with SipDroid that we may need to resolve if we select it for our implementation (http://code.google.com/p/sipdroid/issues/detail?id=60).

–  Twinkle Phone open source SIP client –  OpenSIPS server (for ivMesh)


Maximize attenuators to force auto-re-routing of traffic flow to test self-healing

Fixed attenuators to set traffic flow via one branch or another to test self configuration

1

Traffic analyzer

Traffic generator

Fail-over conditions Emulate failure conditions by setting programmable attenuators to cause traffic flow reconfiguration.

All mesh nodes are in RF isolation boxes

Test the operation of VoIP over 802.11s by constructing this mesh topology. Each mesh node is a PC running the prototype software. Simulate the motion of the mesh nodes by varying programmable attenuators under software control. Verify and refine the self-healing capabilities, which are critical to a mobile mesh network.



•  In September of 2010 the FCC has reaffirmed its decision to allow unlicensed communications in the White Spaces UHF band that neighbors the PS 700 MHz band

•  If 700 MHz 802.11 RF front end chipset is developed for the White Spaces market, it could be used to extend the range of the ivMesh talkaround communications. Otherwise unlicensed 800/900 MHz band could be used for ivMesh. [5]


•  NPRM in May 2004 –  http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-04-113A1.pdf

•  November 4, 2008 FCC approved Report & Order 08-260, allowing unlicensed use of TV band spectrum

–  http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-01-260A1.pdf

•  February 17, 2009, the FCC released the final rules for “Unlicensed Operation in the TV Broadcast Bands”

–  http://edocket.access.gpo.gov/2009/pdf/E9-3279.pdf

•  Sep 23, 2010 The FCC reaffirmed a 2008 decision to open the broadcast airwaves

NPRM = Notice of Proposed Rule Making


•  Ofcom (UK) is in the process of making this Digital Dividend band available

–  https://mentor.ieee.org/802.18/dcn/09/18-09-0059-00-0000-ofcom-update-on-the-digital-dividend.ppt –  http://stakeholders.ofcom.org.uk/consultations/geolocation/summary

•  ECC of CEPT in Europe has published a report on White Spaces in Jan 2011

–  http://www.erodocdb.dk/Docs/doc98/official/pdf/ECCREP159.PDF

•  China TV band regulations expected in 2015

ECC = Electronic Communications Committee CEPT = European Conference on Postal and Telecommunications


DB 3

DB 2 DB 1

Mode II Device

Mode I Device

GPS Satellite

IETF PAWS

IETF = internet engineering task force PAWS = protocol to access white space

Geolocation

Available channels

Spectrum access is database-driven. Database is designed to protect licensed TV transmitters from interference by unlicensed White Spaces devices.


Channel # Frequency Band 5-12 174-230 MHz VHF

21-60 470-790 MHz UHF

61-69 790-862 MHz

White Spaces

Channel # Frequency Band

2-4 54-72 MHz

VHF 5-6 76-88 MHz

7-13 174-216 MHz

14-20 470-512 MHz** UHF

21-51* 512-692 MHz

Fixed TVBDs

only

*Channel 37 (608-614 MHz) is reserved for radio astronomy **Shared with public safety

Transition from NTSC to ATSC (analog to digital TV) June 12, 2009 freed up channels 52-69 (above 692 MHz)

White Spaces

US – FCC

Europe – ECC


0 100 200 300 400 500 600 700 800 900

US (FCC) White Spaces 54-72, 76-88, 174-216, 470-692 MHz

European (ECC) White Spaces (470-790 MHz)

MHz Low 700 MHz band

High 700 MHz band including Band 14 PSBB and PSNB

US Licensed UHF Spectrum

PSBB = public safety broadband BSNB = public safety narrow band

700 MHz PS RF front end could serve PS band along with the international White Spaces band. Commercial chipsets may be coming to support this band for White Spaces.

NPSTC is a federation of organizations whose mission is to improve public safety communications and interoperability through collaborative leadership.! 26 www.octoscope.com

IEEE 802.11 (Wi-Fi) operates in the ISM-2400 and ISM-5800 bands and in the 5800 UNII band; recently standardized for 3650-3700 contention band

IEEE 802.16 (WiMAX) operates in the UNII/ISM band and in the 3500-3700 MHz contention band

Cordless phones

ISM-900 traditionally used for consumer devices such as cordless phones, garage openers and baby monitors, now also used on smart meters

proprietary Standards-based

UWB based WiMedia is a short-range network operating in the noise floor of other services


Frequency range! Bandwidth! Band! Notes!

433.05 – 434.79 MHz$ 1.74 MHz$ ISM$ Europe$

420–450 MHz$ 30 MHz$ Amateur$ US$

868-870 MHz $ 2 MHz$ ISM$ Europe$

902–928 MHz$ 26 MHz$ ISM-900$ Region 2$

2.4–2.5 GHz$ 100 MHz$ ISM-2400$International allocations (see slides 7, 8 for details)$

5.15–5.35 GHz$ 200 MHz$ UNII-1,2$

5.47–5.725 GHz$ 9RR$K0S$ TUNNV9$4W3G$

5.725–5.875 GHz$ 150 MHz$ ISM-5800 UNII-3

24–24.25 GHz$ 250 MHz$ ISM$ T>D$#O%)+4$

57-64 GHz 59-66 GHz$ 7 GHz$ ISM$ US

#O%)+4$

Emerging 802.11ad 802.15.3c, ECMA-387 WirelessHD

802.11b/g/n, Bluetooth 802.15.4 (Bluetooth, ZigBee), cordless phones

802.11a/n, cordless phones

Smart meters, remote control, baby monitors, cordless phones

Medical devices Remote control

5A4%(?&7D$(-?.O'(-8$T>$&-'$@&-&'&J$$5O73%&.(&D$N7%&4.$

RFID and other unlicensed services

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Possible VHF bands for ivMesh


•  Fraunhofer Institute FOKUS, Germany –  www.FOKUS.fraunhofer.de/go/ngni –  www.FUSECO-Playground.org –  www.OpenEPC.net

•  Open source EPC and IMS over LTE


AAA! Authentication, Authorization, and Accounting$BSI! Bridging Systems Interface$CMAS! Commercial Mobile Alert System$EPC! Evolved Packet Core$HSS! Home Subscriber Server$IMS! IP Multimedia Subsystem$ISSI! Inter-RF Sub-System Interface$IWK! Interworking$LI! Lawful Interception$LTE! Long Term Evolution$MAC! Medium Access Control$MC! Mission Critical$MPS! Multimedia Priority Service$MS! Media Server$OMA-DM! Open Mobile Alliance – Device Management$PCRF! Policy Charging and Rules Function$POC! Push to talk Over Cellular$PS! Presence Server$PSAP! Public Safety Answering Point$PTT! Push To Talk$VR! VoIP Recording$XDMS! XML Document Management Server$

Documents

MLINARSKY Considerations for PS LTE architecture 10929 – Handset and network architecture for a PS LTE MC ... Network 3GPP Non-LTE Access: GPRS, UMTS, ... Issue with conventional