1. Push To Talk Over Cellular: Still Searcing The Flow Of Success Research Seminar on Telecommunications Business II Seminar presentation 12.4. 2005 Raili Koivisto Helsinki University of Technology

2. Contents Introduction Benefits for end-users and operators Technology options and substitutes Performance Vendor and operator strategies Pricing Regulation Conclusions

3. Introduction PTT is a half-duplex voice service PTT available since World War II with limited coverage but minimum charges In 1996 Nextel begins to rollout iDEN PTT in cellular networks is called Push-To- Talk over Cellular (PoC)

4. PoC

5. PoC building blocks PoC Server for floor control and speech traffic SIP IP Core for signalling GLMS for group management Presence Server PoC Client in terminal

6. Benefits for end-users Immediate wireless contact to a pre- defined person or group Worldwide network Suitable for group of friends, hunters, small businesses

7. Benefits for operators Enables to compete with existing PTT services Enhanced voice services New usage models -> more usage -> increased ARPU in developed markets New users in developing markets Efficient way of using network resources

8. Technology options OMA PoC by Ericsson, FastMobile, Motorola, Nokia, Siemens, Sonim –CDMA, GSM, WLAN, client-only implementation –IMS architecture based iDEN by Motorola –Fast ”chirp to talk” times –Proven solution QChat by Qualcomm –CDMA only –BREW client-only implementations Circuit-based PoC by Kodiak Networks –Network agnostic –Circuit connection after call set-up -> cost, radio resource use

9. Substitutes Conference call –No savings in cost or radio resource, slow to set up Fastchat –Client integrated in Symbian SKYPE + PDA + WLAN –Peer-to-peer, no central host, limited user base –Smaller savings in cost or radio resource Push-To-Talk over Bluetooth –Short range only –Free of charge –Hybrid with PoC possible Instant Messenger solutions –Limited terminal selection

10. Performance Circuit-switched PoC over 6x more expensive than PoC over GPRS PoC over GPRS 5x more efficient, PoC over EGPRS 14x more efficient than over GSM Latencies remarkable in GPRS Voice quality on GSM level, BER quite high Performance depends on end-to-end tuning

11. Vendor strategies Several camps beside OMA standardization work, other technologies also further developed Use of pre-standards to colonize markets Clients available in phones Trials with operators ongoing

12. Operator strategies 35 operators using pre-standard solutions now, 14 of them using Kodiak in CS Others waiting for OMA standard? –Or thinking positioning/pricing/target groups? –Or gathering money for new investments? –Or denying to cannibalize existing business? Charging requires interconnection agreements Lacking walkie-talkie culture in Europe

13. Pricing OMA architecture supports several pricing methods In US subscription fee includes certain no of minutes In Australia normal call charge doubled Simple pricing model encourages users Pricing now – pricing in future

14. Regulation Is PoC a voice service which should be regulated (legal interception)? EU wants to encourage, not restrain diffusion of VoIP, FCC on same way but… Privacy of user data, presence, location, group lists has to be regulated Regulation needed for competition issues Not applicable for emergency services

15. Conclusion Technology push but no dominant design yet High performance and worldwide interoperability require standard based solutions Proven use case in US but does it work in Europe or Asia? Is there enough attractiveness before multimedia convergence and virtual reality solutions?