Generations of wireless networks Chapter 1
Where is wireless access going??? • Many (maybe too many) wireless technology choices are available today • Short-range (WLAN’s, sensor technologies such as Bluetooth or Ultra Wideband) • Long-range (Cellular) • Broadband (WiMAX/WiBRO, Flash-OFDM, etc.) • Broadcast (DVB-H, DMB, MediaFLO) • Device segmentation is not universal • Can vendors address the needs of the subcontinent while still making a global product? • Democratization of wireless technologies • Sales channels in the subcontinent are so varied – do device features have to stop with the original manufacturer?
So Many Technology Choices 6. 3.9G 5. 3G+HSDPA 3G+HSUPA 4. WiBRO WiMAX (fixed) WiMAX (mobile) 3. WLAN Hotspots 2. Flash-OFDM 802.20 1. 3GPP2 systems (1X, EV-DO, nxDO, “Phase II” Evolution) 2005 2009 2006 2007 2008
Cellular technologies • Mature – GSM/EDGE, CDMA • Voice-only products approaching commodity status • Ongoing rollout – 3G (WCDMA) and 1X-EV-DO (CDMA evolution) • What are the usage scenarios in the subcontinent? • Bringing the internet to underserved user segments? • Fancy services for a very small, very rich niche? • Future – 3.9 G • Extending the high throughput capabilities of WLAN technologies into cellular • Short range technologies (WLAN primarily) • Not much good without an internet backbone; goes hand-in-hand with broadband penetration
Wireless broadband • Slowly gaining traction in the West; telecom operators are cautious because of previous overinvestment in other broadband technologies (DSL, optical) • Very clear usage scenario in the subcontinent • Strong backbone solution: can bring internet access to remote areas and villages • Is there enough business to get a major telecom vendor excited? • Broadcast for wireless (DVB-H, DMB, MediaFLO) • Certainly a proven appetite in Asia for TV • Hard to say if users in the subcontinent will watch TV on small devices
Future Wireless System Development • Increasing penetration • Lowering costs of devices • Improving return for operators • Customizing services for the local population • There is a quandary with going forward with a regional technology • Will global vendors support it? • If not, is there a local vendor base? • Is the scale of the technology large enough to drive down cost?
Low penetration provides some opportunity • Legacy of cellular circuit-switched services (particularly voice) not insurmountable • Rather than develop a new technology for South Asia, subcontinent researchers should try to drive locally enabling technologies through standardization, for example • Improve cellular technologies for VoIP, enabling lower cost backbone • Advanced cellular receiver design to improve voice capacity • Driving targeted features in global standardization would be a win-win scenario for South Asia and the global vendor community • Global technologies mean large scale – costs can go down • Opportunity for Asian researchers to influence standards that are deployed over the world • Cellular is the best choice
End-User Needs Mobile Device High-End Business Communicators Advanced Wireless Services (e.g. E-mail) Smartphones &messaging devices Messaging and Limited Wireless Services Voice Voice-centric devices Devices
Wireless Access Mapping • Voice-only • 2G (GSM, cdma2000 1X) • Messaging and limited data services • 2G (GSM, cdma2000 1X) • Advanced wireless • 2G (GSM, cdma2000 1X) • 3G (WCDMA, cdma2000 1X-EV-DO) • High-end business/multimedia • 3G (WCDMA, cdma2000 1X-EV-DO) • Complimentary access (WLAN a definite, maybe WiMAX)
Democratization of Wireless Technologies Example: Research conducted in Delhi by Nokia Research Center’s Usability Group, Tokyo
Karol Bagh market area of Delhi, India 200 + small indoor shops, and 100+ outdoor market stalls
this one building, approx. 60+ small shops spread over 4 stories wholesaling phone accessories and repair equipment small workshops actively repairing phones, and offering training
minimal street customer care center = flat surface + screwdriver + new component + knowledge
What can we take away? • Huge after market service industry has developed in South Asia • Phone repair, re-sale • Reconditioned phone sales may be the ticket to providing new cellular service to customer segments, e.g. • Basic voice to BOP • Advanced multimedia to existing voice-only users • Large proliferation of after-market services may also be able to provide some limited enhancement to cellular devices • If multinational vendors can tap into this more effectively rather than view it as a threat, then consumer insight could result • Are there low-cost innovations that could better serve an emerging market?
Wide Area Wireless Technology What are the next few years going to bring?
From the Seventies through the Nineties, most cellular systems were developed through consensus and standardization • AMPS was a technology delayed nearly 20 years due to building consensus! • GSM has proven to be long-lasting and widely-supported – also developed through industry cooperation • In the Nineties, proprietary technologies emerged • IS-95 (“CDMA”), proposed by Qualcomm Inc. • Followed by 1X-EV-DO in the late Nineties • Nowadays, several more proprietary alternatives to standardized cellular technologies have gained notoriety (not necessarily widespread adoption) • Flarion’s “Flash OFDM” • Other technologies may be “nearly proprietary”, with a small number of companies driving development
What makes proprietary technologies attractive? • Good ideas are sometimes compromised in the standardization process • Standardization process can delay product development • Proprietary route has pitfalls • Lack of widespread vendor support for a given technology • Intellectual property concentrated in the hands of a few players • Is there a middle ground? • Yes, when a small group of companies who can support a given technology develop it together outside of standards • Standardization can follow, to allow other equipment manufacturers exposure to the technology and ensure interoperability
Where does spectrum come into the picture? • Spectrum is not as cheap as once thought • North American example: recent consolidation among operators has left winners and losers in spectrum • New 3G spectrum auctions (1.7/2.1 GHz) have not happened fast enough to address this • Operators want to evolve existing cellular technologies in a manner that continues to leverage their huge investment in 3G equipment • Backwards-compatibility will be a driver • Makes it difficult to find a disruption point for good proprietary technologies • The overlap period becomes a driver – how long does the network operator have to support legacy subscribers while the new technology is being introduced?
These are issues that will influence the evolution of cellular technologies • New cellular systems will leverage as much as they can from legacy systems • For example, reuse of control/overhead mechanisms from legacy • Baggage from the legacy systems can reduce the benefits from innovation in evolution systems • In response, wireless vendors need to get more creative as to what defines “backwards compatibility” • Need to be selective in what is actually leveraged from the legacy system • Also, need to consider how much evolution in the air interface technology is necessary for improving system performance • Can improved performance be addressed through software/middleware innovation?
Wireless broadband (802.16) • Slowly gaining traction in the West; telecom operators are cautious because of previous overinvestment in other broadband technologies (DSL, optical) Technology positioning is a problem for cellular operators already deploying 3G • The target customer base overlaps • Broadcast for wireless (DVB-H, DMB, MediaFLO) • Certainly a proven appetite in Asia for TV; bodes well for DMB in East Asia • European and North American markets unproven yet for handheld digital TV
What about Voice Services? • Voice is still the killer app for cellular • Without a compelling data application for 3G, it may be a safe starting point to say that VoIP will be the killer app for 3G evolution • This profoundly affects cellular evolution • Air interface must be optimized for low rate, low delay service such as voice • This could come in conflict with design goal of extending high speed capabilities seen in WLAN to cellular • As long as voice is perceived as a separate revenue stream rather than just another IP-based service, this could hamper cellular evolution • In other words, should future cellular systems performance be benchmarked primarily by voice spectral efficiency?
Quality-of-Service for Internet ApplicationsShould cellular provide the same as broadband? • Many internet applications are not designed with a cellular link in mind • Underlying expectation of relatively constant quality of service (QoS) • Throughput is assumed to be known during session setup • Certainly totally different applications can be designed for cellular, but some innovation in the middleware area may improve application performance over cellular without • Redesigning air interface • Rewriting application • Example: online multiplayer gaming (“First person shooter”) • Player actions based on other player actions • Near real time