T-109-551/TAV/6.4.2004

Push Over Cellular

T-109.551 Research Seminar on Telecommunications Business Seminar presentation 6.4.2004

Timo Ali-Vehmastimo.ali-vehmas@hut.fi

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Structure

What is PoC ? Standards and Technology Value System options Regulation Key Benefits Service Adoption Observations and recommendations

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What is PoC ?

“Push to talk over Cellular (PoC) is intended to provide rapid communications for business and consumer customers of mobile networks. PoC will allow user voice and data communications shared with a single recipient, (1-to-1) or between groups of recipients as in a group chat session, (1-to-many) such as in figure 1 below.”

Member A

Member B

Member C

Member D

Member EWireless Network

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Modern History of Push to Talk

Push to talk is the most primitive radio system. Its roots are in the military radios, used extensively in dispatch (e.g. taxi etc.) and also in consumer (VHF, CB radio) market

Nextel with Motorola and Nortel created new radio system, IDEN (Integrated Digital Enhanced Network) to compete with IS-54/136 (TDMA) and IS-95 (CDMA).

Main driver was available ESMR (PMR) radio spectrum, which Nextel had available based on the earlier network.

Network was launched 9/1996 in Chicago metropolitan area. First services included voice and text paging and the key feature, two way radio, ie. push to talk.

Service and coverage evolution during the next first years. Other new services in Nextel network very similar to basic cellular services of that time period.

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Nextel network, service and business case

Currently Nextel service is very similar to any 2nd generation digital cellular service, with many phone models, all kinds of accessories and ring tones, location services etc. Also strong investment in JAVA (J2ME) service platform.

Nextel claims to have the best quality overall service concept with network quality among the top 3.

Nextel has today some 12,3 million subscribers (24% yearly growth).

Service has been adopted by ordinary consumers too. 90% of the users use also Direct Connect. 50% more Direct Connect calls than ordinary calls per user

Push to talk service extended to nationwide coverage and will be extended to international connections later.

Service quality is good. Latency < 1 sec. Strengths: Good service quality, Integrity of the services,

Strong financial Weaknesses: Coverage, Volumes, Choice of Vendors,

proprietary technology

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Standardization status and goals

Industry standard (Sony/Ericsson (Sonim), Motorola (Magic4 Metrowerks), Nokia, Siemens) Basic functionality based on the prototyping individually in each company Basic functionality has been proven and key technical issues have been

identified OMA

Committed to drive a harmonised standard which is targeted to fit for GSM/WCDMA/GPRS system and also for CDMA2000 system.

Intention is to use IETF specifications as much as possible as they are in order to achieve compatibility also with Internet.

3GPP IMS Basic SIP based infrastructure for Internet Multimedia services on top of

the GSM/WCDMA/GPRS radio network. POC can be seen as one application level protocol and service set utilising

features and functions as much as possible as they already have been specified in 3GPP.

IETF Protocols for Internet, which now have been adopted by 3GPP and

partially by OMA TCP, UDP, HTTP, SIP, SDP, RTP, RTSP, RTCP, …

3GPP2 Counterpart for 3GPP, Specifications developed for CDMA2000 Will follow as much as possible 3GPP IMS, OMA and especially IETF

3GPP RAN Core

3GPP IMS Core

POC Application

Physical Layer(E)GSM/WCDMA

Link LayerGPRS

IP Layer(IPv4, IPv6, IPSec)

Transport Layer(TCP, UDP)

Session Layer(SIP, HTTP, XCON)

User Data Control(RTP, RTSP)

Content/ Data(AMR)

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Standardization Issues

3GPP Current related work items for Multimedia Conferencing, Presence and Instant Messaging partly overlapping with OMA activities

IETF has created parallel specification for Multimedia Conferencing. XCON – Floor control signalling and conference policy SIMPLE – Resource Lists and Ad-Hoc Resource Lists SIPPING – Requesting Multiple Targets, Conference signalling framework

Industry specification contributed to OMA is based on IPv4 while IMS is on IPv6. There are also other deviations in order to achieve short time to market.

OMA specification should be fully harmonised with 3GPP IMS Security mechanisms are different (HTTP digest vs. IMS AKA) Floor Control (no earlier standard exist) Group list management

More Network interfaces needed for genuine multivendor/multioperator network POC Server to POC Server Interface

Some dedicated features for CDMA2000 No PDP contexts => Using “one context only” option Utilising CDMA short burst for floor control

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Key Technology elements and issues

Always on packet radio connection to Internet Access Points SIP based session setup Half duplex VoIP

AMR Codec as default, Other codecs open POC Server always needed.

NAT and Firewall traversal

How to optimise for all relevant radio standards QoS, IPv6, SIGCOMP, Header Compression, Multiple PDP contexts

Performance of POC Setup times, Voice delay and quality

How to achieved multiple simultaneous speakers Virtual reality, faster response, more conversational Enhancing the current approach vs. two or more parallel sessions How to support any Multimedia Content

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PoC architecture as proposed in OMA

PoC is implemented as Application Server on the top of the IMS infrastructure. Also Authentication, Charging etc. fundamentals provided by cellular network as default

PoC concept includes also Group management Server

PoC will interface to other Application servers, such as Presence, Location, etc.

PoC Client is implemented on terminals, utilizing terminal capabilities such as ISIM/USIM, User Interface, Phonebook, Audio, Video and other multimedia sources and sinks.

PoC Client may be implemented as downloadable software if terminal device supports well-specified open API’s

PoC client

GLMS

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Bold box identifies PoC functional entities

Presence Server

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It: Floor Control and media Is: PoC Client to Proxies Session Signaling If: Proxy to PoC Server Session Signaling Im: Group Mgmt to PoC Client Ik:Group Mgmt to PoC Server

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Value System options for PoC

Open Interfaces between the PoC server and the IMS Core network will enable many different models for service provisioning.

Especially Corporations may seek to run their own PoC server similarly as they run the PBX today.

Also open competition (fuelled by liberal regulation such e.g. Number portability) between various network operators makes it impossible to define predominant candidate to run successful PoC service

PublicPoC

Service

PBX or Centrex orPublic PoC

Service

Legend:

Access Operator

Network Operator

Value AddedService Provider

Enterprise

Backbone Operator

CorporateEmployees

Conusmer

Virtual NetworkOperator

ContentProvider

Internet ServiceProvider

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Proprietary Systems

Fastchat by Fastmobile (Ericsson, Symbian) Proprietary version of similar service (Client/Server

model) Downloadable to Symbian products Integrates Push to Talk with messaging and presence,

Also multimedia support Service available Not compatible with OMA PoC

Skype Peer to Peer (Fixed) Internet Voice service. No central host is needed but because of NAT/FW

traversal at least some hosts must have direct connection to Internet

Not optimised for Wireless, will probably require 4 to 10 x more bandwidth. Currently runs only on Windows

Nothing prohibits making wireless friendly version Claim: 100k+ simultaneous users in Skype

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Regulating PoC

Legal Interception Is PoC a regulated voice service ? May not be easy to implement for all PoC groups

Competition Open Interfaces enable competition Regulation needed to facilitate non-discriminatory pricing

Privacy Privacy of GLMS data bases Privacy of PoC Server user data Privacy of Presence and Location and other information

PoC is not applicable to Emergency Services Should not be used for 112 calls either

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Benefits for end users Social connectivity, within

cellular coverage

Hunting parties, Sports events

SME dispatching Virtually Unlimited number

of participants

Benefits of the PoC

Benefits for the operators New service with moderate CAPEX, Using already

invested GPRS/Packet radio Infrastructure Service segmentation

Text messaging Audio/MMS PoC Voice

Service Differentiation with proven used case (USA)

Centrex like service offering to (small) enterprises

Benefits to manufacturers New products needed (both Infrastructure but

especially terminals) New business opportunities for SW vendors May impact also the platform competition

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Operators and Vendors supporting PoC

Telecom Operators: Vodafone, China Mobile, Orange, 3, Cingular, AWS, TIM, T-Mobile, Verizon, Sprint, ..

Telecom Vendors: Ericsson, Motorola, Nokia Siemens, Alcatel, Samsung, NEC, AIS (Thailand), Telstra, Optus,…

Dedicated vendors: Sonim, Fastmobile, Magic4, Kodiack Networks, Ecrio Inc., …for Symbian, Palm OS and Microsoft SW platforms and TI (OMAP) HW platform.

Corporations as customers: ?

Internet Service providers ?

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Factors impacting diffusion 1/3

Service discovery Proven used case

Nextel 12 million customers with highest ARPU in USA Word of mouth

For market where low awareness of Push to Talk (Europe)

Service trial Downloadable application

Available from several vendors Performance may be an issue of downloadable applications without

HW support Downloadable settings

Shall be part of the application downloading or to be ordered like other service settings (ref to MMS settings etc. using e.g. OMA Provisioning)

Price of the Application Should have Trial version for free, permanent version like Browser

(Opera 20€)

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Factors impacting diffusion 2/3

Using PoC Application performance and Usability

Setup delay > 4s, Floor control delay > 1.6 s Voice Quality (MOS>3 @ 2% BER) Dedicated key, Indication of Floor Control, Indication of speaker, Easy

Group management and Invitation Peer Group pressure Price of the Service

Current GPRS tariff 18€/100 Mbytes ~ 2,2 snt/minute / 1 air hop Half duplex point to point “conversation” ~ 5 snt / minute. Cost shared equally for both /all ends

Availability of multiple products and operators Must be Several compatible products for all product categories Should have Several service offerings, Multioperator support, Incl.

Roaming

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Factors impacting diffusion 3/3

PoC as an Integral part of Wireless Communication Integration with other applications (Presence, Messaging,

…File sharing, Calling, Phonebook etc.) Applicability of PoC to Enterprise Use Multimedia Conferencing using PoC Virtual reality of the conference by full duplex voice connection Applicability of PoC to any (Wireless) IP based environment

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Walled Garden for PoC ?

Value system of Push over Cellular may be compared to Centrex / PBX development Centrex PoC

Operator manages all the services Centralised service Low level experimentation Suitable for low market uncertainty

PBX PoC Enterprise manages services Distributed service, May be several

PoC servers in one company, each for each department

High level of potential experimentation

High level of innovation Suitable when high market

uncertainty

Current market uncertainty

High: Several standards proposals No dominant design Expert opinion

Low: Proven Use case in US

=> There is a risk for slow service start-up if walled garden is the only possible/legal approach

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Integration and Interoperability

1. Current goal is to provide Operator domain PoC

2. Second level to provide Operator to Operator interworking within one system technology

3. Third level to provide Operator to operator regardless of system technology

4. Fourth level is to support also enterprise solutions

5. Fifth level is to allow ISP solutions

6. Sixth level is to make all this to interoperate

GSM/GPRS/WDCMA

CDMA2000

INTERNETINTRANET

POC ASCORP A

POC ASOPER A

POC ASOPER C

POC ASISP D

WLAN

WLAN

POC ASOPER B

Value ~ N2

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Winning concept in many value systems

PoC has proven used case, but only in USA

Standardised solution for Commercial PoC is needed for high performance of the overall system and for interoperability

Standard based solution shall be open also for enterprise and private use

All IP nature of PoC does not meet all the regulative requirements of voice service. Does this matter ?

Downloadable applications lower the risk in service adoption

Price of equipment and service can be competitive

Distributed business models will be important for the success of PoC

Multimedia Convergence and virtual reality can be the final target with several evolutionary steps

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Thank You