re: Issues with GPRS (EMC) Revisited - long but comprehensive repost
I decided to repost this excellent ten month old article.
It is interesting to see how far the GSM community has come in the 10 months since obstacles to GPRS success were defined.
The majority of technical issues are behind, and networks are stabilizing and being optimized. Handsets are becoming relatively plentiful and now appear to be operating reasonably well. Capacity issues will still need to be dealt with.
The fruits of the Natnilli labor should ripen this fall.
It is hard to say whether mass deployment of GPRS will begin before the upcoming Xmas season or shortly thereafter, but irregardless by the end of 2003 deployment should be in full swing.
By that time WAP 2.0, refined J2ME Java and Java Apps, MMS, GRX Roaming, content development, color displays, Blutooth PLAN, and WLAN should all be working in concert to drive meaningful data services and replacement handset sales.
Virtually all of these obstacles (barring a few technical issues that are GPRS specific) face the CDMA community as well. It is unclear to me what the community is doing about it (outside of Korea).
GSM carriers have always acted in a spirit of "coopetition", and opted for uniform implementation of data services.
I see nothing comparable in CDMAland to the Open Mobile Architecture Initiative, the M-Services Imitative, & GSMA "Fast Track Task Forces":
Message 17158190
The E2E Roadmap of Operator Requirements for GPRS Features and Services is a powerful document (discussed here):
Message 17158190
It is downloadable here:
gsmworld.com
>> Many Obstacles Lie Ahead As Operators Aim For GPRS Roll-Out, Conference Hears
Dennis Andrews
EMC Cellular
11-Jun-2001
e-searchwireless.com.
At a time when the initial GPRS services are taking to the air, IBC held its well-attended GPRS Congress in Rome during mid-May 2001, and coupled it with a single-day seminar entitled 'Is GPRS the Saviour for WAP'. This EMC report centres on the presentations delivered at these two events but also takes in other related research that will provide a comprehensive analysis of the position of GPRS as a 2.5G technology, and its place in the path towards third generation systems.
Opening the conference, Jonas Twingler - Senior Partner at Northstream, reviewed the current market position of GPRS - a delayed start, shortage of choice in handsets, major uncertainties in the market, and fast changing perceived value chains. He highlighted what he saw as the fundamentals for GPRS success:
* Services that the market is prepared to pay for
* Pricing plans that make both sense and money
* Non-voice services that are simple and intuitive in use
* Roaming that is simple and workable
* An understanding of the relationship between GPRS, possible addition of EDGE, and the route to 3G
* Maintaining a grip on related dependencies and enablers - silicon devices, overall technology, business issues
Above all, the industry keeping a focus on what it can do best, and not what seems to be good.
There was a general view that GPRS, with its potential for new customer behaviour, new reasons for usage, and new types of services, will provide the potential for a 'revolution', with 3G/UMTS representing an 'evolution' - more bandwidth and additional complexity of service.
Mobile Data Services Potential
Adam Daum from the Gartner Group, reviewed findings from recent research into the potential for mobile data markets. This had highlighted critical differences between delivery of services in the fixed internet world and that of mobile data service.
Characteristics Fixed Internet Mobile service
Willingness to pay
for content Almost zero Context-dependent
Registration/Opt-in Rare Essential
Accountability for content ISP is just a pipe Operator 'responsible'
Advertising Indiscriminate Opt-in only
Primary role in B2C
e-commerce Information research Decision support
Source : Gartner
The research had also looked into the potential popularity of various types of mobile data services taking Italy as a representative market.
Along with other presentations at the conference, this emphasised the acceptability of messaging and leisure services and the relatively small interest in 'business' applications. The same research provided some interesting information on the attitude of current WAP users, again in Italy, to paying for various types of mobile data service. This market view would support the ongoing introduction of multimedia messaging which is already appearing in the latest handsets.
GPRS Business Models And Value Chains
A number of presentations dealt with the complexity of the business models and value chains that will be associated with the provision of wireless data services.
Janne Pesu, from Sonera, said that despite technical and delivery problems, the GSM industry has generally beaten forecasts all through its short history and it should have the ability to do the same through GPRS and 3G. SMS became a new way to communicate and its low and fixed transaction cost proved to be a winner. By the use of market power, operators have a considerable ability to fulfil their own forecasts, although possibly at some cost.
Although some speakers discussed business models and value chains in terms of applications appealing to mature business users and value-added applications, there was something of an overall consensus that, certainly in the short term, a large proportion of any new revenue would come from the 15-24 year-old group who, as current SMS users, would be attracted by the enhanced message applications and games, and thence to other services.
No speaker was able really to address the growing conundrum that many operators' business plans revolve around continuing ownership of the user and generation of revenue from the associated applications, but that the only financially successful wireless services to date have been built on the principle of the provision of a transparent 'data-pipe' with the bulk of revenue coming from airtime provision (i-mode and CDPD).
Tomas Wedl, from Telering Austria, provided a fairly simple example that highlighted the difficulty of aiming at application based revenue. Telering had attempted to establish a SMS-based service that provided the user with the ability to interrogate a radio station on the identity of music, and then provide the opportunity of ordering a CD online. However, no agreement could be reached with the various entities involved in the proposed service and it could never be launched. He said that for any complex value chain, the successful establishment of cohesive partnerships would be essential; but he had no message on how this might be achieved in practice.
Later in the conference Cindy Dahm, Business Development Manager with Openwave, defined the practices that might be required in constructing a Service Level Agreement with application partners.
* Usability - testing will be key; applications must be based on a Style Guide; every application must be compliance tested; every device and browser must be tested
* Performance and Reliability must be assured
* Information refresh intervals must be agreed
* Dynamic application changes must be controlled
* Copyright issues must be covered
* Privacy issues must be addressed and responsibilities agreed
* Split of revenue from advertising, referral fees and sponsorships must be covered
* Joint Marketing of services must be covered.
Applying The i-mode Experience to the GSM world
A number of speakers discussed the factors that had provided the success of i-mode in Japan. However, there seemed to be few accepted conclusions on how the resulting lessons might be applied to the GSM wireless data market. Some key factors could be distilled from the various presentations.
* The issue of the 'mobile internet' is unlikely to go away and will always present a difficulty of matching user expectations against deliverable functionality
* There is a fast expanding level of attention being devoted to CRM, its relationship to revenue growth and to reduction of churn
* The industry is, at long last, recognising that investment in a new cellular related product or service is, increasingly, an emotional purchasing decision rather than the traditional approach based on a technical and rational basis
Marco Buttazzoni, from Logica Consulting, whose company has been closely involved with the operation of NTT DoCoMo's i-mode network, provided some views on the system development and the factors associated with the rapid growth of its customer base.
He began by challenging a number of the suppositions that have been voiced over supposed 'special factors' in the Japanese market that do not apply elsewhere.
* 'Internet penetration in Japan is low' - not significantly different to most other countries
* 'The Japanese like gadgets' - no more that most other markets
* 'Japanese commuters have lots of time to kill' - no different to other countries
* 'Japanese prefer to write rather than speak' - no significant difference
* 'Japanese consumers are accepting of the principle of paying for data content' - most i-mode data is free.
Buttazzoni pointed out that NTT DoCoMo had originally launched packet mode over their PDC system during 1997; but it was not until February 1999, after a relaunch with a new marketing direction, that the explosive growth in usage began. With standing monthly charges of $3 for basic service additional $7 for data service, i-mode is generating around $18/month/user revenue for DoCoMo. Usage splits as 42% e-mail, 34% voice, and 24% web surfing.
He said that NTT DoCoMo had established a well-founded claim to be the first operator that has generated significant revenue from mobile internet applications in spite of a service that is based on a narrow bandwidth technology; much of this stemmed from the i-mode business model being structured as a 'delivery pipe' and billing engine. User expectations had been successfully contained by presenting i-mode as a new mobile service and not as the mobile internet. Other success factors included a high focus on the consumer, marketing the i-mode handset as a 'fashion item', the use of cHTML and high definition colour displays, and close control of application partners to ensure consistency across all accessed services.
Although the presentation was partly aimed at promoting NTT DoCoMo's efforts to market i-mode outside Japan, the message was that its success came from innovative marketing and not from the underlying technology.
Data Applications for GPRS Users
Some global concepts emerged from discussions on application provision.
* In the short term, at least, WAP will be the principal vehicle for the supply of data services
* Evidence suggests that leisure related applications will still be more popular than business applications
* In design of applications, the 'three click concept' is of great importance. This says that a user will accept up to three keystrokes in order to access required information. Every keystroke beyond three diminishes acceptability by a cumulative factor of 50%
* Some applications, such as MS Outlook, take a lot of time to establish due to handshaking requirements and will only operate satisfactorily with the addition of application accelerators.
WAP
Opening the one-day seminar on WAP, Jan Ten Sythoff, from Frost & Sullivan, listed the shortcomings that had undermined the technology in the early days and which should be successfully addressed in a GPRS environment.
* Bad user interface - small screen size, lack of colour and graphics, unwieldy input capability
* Poor device availability and capability
* Connection slow and expensive
* Poor interoperability
* Lack of compelling or easy to access applications and content
* Many operators over-stretched and trying to do too much
* Difficulties in bringing together all the elements of the value chain and making them work together.
GSM/WAP to GRPS/WAP Migration
Cindy Dahm, with Openwave, defined the issues involved in migration from GSM/WAP to GRPS/WAP
Requirements:
* Portable, IP-based portal framework that will operate simultaneously on both GSM and GPRS
* Performance test lab to ensure application compatibility
* Handset and browser specification and certification process
* Home page segmentation capability.
Migration Process:
* Test end-to-end WAP over GPRS for performance and reliability
* Isolate individual network performance issues
* Work through issues by vendor - ie router, handset, browser.
Application & Services Access Roaming and Home
Max Kopjin, from AtoBe, explored the technical complexities involved in providing application access in both home and roaming environments. He identified three different classes of application services and the associated platform requirements.
Mobile Portal Services
* defined as a starting point for the provision of information, entertainment and transaction services
- Scalable dial-in capacity in various European countries for access from different mobile networks (GSM, GPRS and UMTS
- Scalable WAP- and SMS-gateway capacity
- Scalable mobile portal application hosting capacity
- Over-the-air configuration and ringing-tone functions for different handsets
- Personalisation and search functions
- Location-based functions
- Billing and security functions
- Aggregated usage and profiling reporting functions
- Advertising Functions
- '24x7' availability of all the above platform elements.
Mobile Workforce Services
* defined as those allowing employees to access corporate databases
- Requirements as for mobile portal services with some additions
- More advanced security functions
- A broad range of software packages to mobile enable existing corporate application.
Mobile Applications Services
* defined as the actual provision of a range of information, entertainment and transaction services
- Connection to portals from mobile operators and independent brands in various countries
- User access via a broad range of network bearers (SMS, GSM, GPRS and UMTS)
- Scalable mobile application hosting capacity
- Simple and uniform access to an increasing range of common mobile application features such as user identification, user profiling, handset specification, portal specification, user location specification, security options and billing options.
Kopjin went on to discuss the options for physical connection between networks and an independent mobile application portal. There are two options:
1. The platform connects directly to the GGSNs of the operators
2. The platform connects to the SGSNs of the operators via a GRX.
In the first case, the portal operator must establish connections to each operator through which the service is to be accessed - either through a lease line or IP-VPN connection. The second case is more attractive to portals as is would be more flexible in securing bandwidth, provide instant connection to new operators, and the GRX provider would guarantee 99.9% network availability. However, the operators are unlikely to agree to the required bilateral roaming agreements with an independent mobile portal to enable these GRX connections although some external data providers, such as banks, would see this path as providing the required level of access and firewall control for applications with high security requirements.
Many surveys have pointed to messaging applications as providing significant attraction to potential users of wireless data services. The present email services will be enhanced, in a relatively short timescale, with the addition of multimedia capabilities. In the USA the Blackberry PDA, although not strictly a cellular device, has built a significant market share. This product range will appear in GSM/GPRS markets and Rick Constanzo, Director of European Sales for Research in Motion provided a study of their experiences in the messaging environment.
* Currently 283 million corporate mailboxes worldwide - 70 million of these are in Europe
* The number of corporate mailboxes worldwide grew 510% between 1997 and 2000
Average number of messages received by end users is expected to jump 81% to 34 per day by 1Q2001
* The average corporate email user spends over two hours a day processing e-mail messages
* 90% of senior corporate email users would like to send and receive e-mail by wireless. <<
Network Capacity Issues And Gprs Limitations
Although high usage of GPRS does have implications for overall network capacity, most operators seem to be confident that the growth rate will not exceed their current capacity growth plans. While user numbers are low, operators will be reluctant to allocate timeslots for exclusive GPRS use. Under these circumstances, voice traffic will take precedence over packet data and users will notice a reduced response time. It also appears that where the network is unable, for any reason, to establish a GPRS session in response to a request from a user, most handsets will default to dial-up mode; and this may not be apparent to the user unless there is close inspection of the display icons. This clearly has billing implications and may result in unexpected high charges being presented to the user.
Where there is strong demand for higher speed data service, operators have, in theory, the option of implementing the higher rate coding schemes 3 & 4. But these would require extensive and costly upgrades to infrastructure and the general feeling is that any significant deployment is unlikely.
Taeke Castelain, from BlueKite, explored some of the issues that would arise from an unexpected, rapid commercial uptake of GPRS service. With a current practical limit of 4-timeslots due to radiation and heating issues and relatively high network latency (the overall roundtime response for an application), there should be an understanding of the 'transport efficiency' for different types of traffic - ie the associated potential value versus volume. Values are compared, taking values for a typical speech application as a base. This shows that the relative efficiencies associated with proposed GPRS and 3G applications quickly falls; and this will be aggravated with the inclusion of colour support and enhanced graphics - both considered essential for success in wireless data markets. Castelain pointed to the advantages that will come from advanced methods of data compression that are marketed by his and other organisations.
Content Volume (kbyte) Value Transport
Efficiency
Speech 100 (1 minute) 1 1.00
Message/Text 1 (1 message) 0.5 50.00
Web browsing 1000 (5 minutes) 1 0.10
Images 1 (1 image) 1 1.00
Audio 1000 (1 song) 0.5 0.05
Video clip 1000 (30 seconds) 5 0.50
Video call 2000 (1 minute) 3 0.15
This theme was followed up in a number of presentations from operators that have already launched service. T-Mobil summarised the steps required to maximise performance:
Step 1 - Optimise throughput and latency of transmission chain
Step 2 - Adjust TCP parameters to the GPRS case (MTU, window size etc) in the proxy between the internet server and GGSN
Step 3 - Speed the proxy by
- Usage of recent HTTP version (e.g. HTTP 1.1; request pipelining, persistent connections)
- Lossless compression (e.g. gzip on HTTP layer)
- Lossy compression (maximum jpeg, reduce number of colours/pixels)
- Caching
- On average, acceleration by a factor of two is achievable without dramatic loss of picture quality.
Handsets, Power Management, Chipset Development
A comprehensive report on handset availability was published by EMC at the time of CeBIT at the end of March 2001 () and there was little further information available at the Congress. There were suggestions that manufacturers are holding back on delivery of new models while interoperability issues are resolved. Some suppliers, Siemens being mentioned as one, are planning to allow field upgrades of handsets to allow for revisions to operating protocols that might be introduced to overcome early implementation problems. There was a wide view that a high proportion of handsets will eventually support GPRS as a standard feature.
Richard Lodge, from Tropian, reviewed the issues affecting chipset development for 2.5 and 3G systems.
High data rates depend upon use of multiple timeslots. GPRS Class 12 operation can demand up to four timeslots in either direction. The resulting increase in power amplifier current, together with increased CMOS dissipation due to the higher computation load, potentially causes a large increase in thermal dissipation requirements of the handset. If EDGE is implemented, the PA efficiency drops to less than half of that realised by the current GMSK modulation method. This will result in further heat dissipation requirements
Manufacturing issues. There are a number of manufacturing challenges concerned with power control accuracy and repeatability, phase error variation, switching transients repeatability, and parametric variability.
Chipset designers are developing new technologies which will address these issues for both 2.5 and 3G. Amongst these new techniques is Polar Impact Technology which is a digital, strongly non-linear transmitter solution, which as well as reducing overall power consumption and consequent heating effects, significantly reduces component count in the device.
'Always-On' Issues And Ip Addressing
During the conference, the issue of GPRS being an 'always-on' system was questioned on a number of occasions. It appears that, at least in the short term, there will be many occasions when a GPRS terminal is not 'always-on'.
Issues arise from a number of factors.
* IP addressing - there are just not enough IP addresses available for an individual designation to be issued to each GPRS handset; this means that connected terminals must use a dynamic IP address assigned by the network for the duration of a session. It follows that where the session terminates, the handset will, effectively, no longer be connected. This will appear to the user as a delay in response as the handset waits for the network to re-establish addressing. An alternative approach for operators is to employ Network Address Translation (NAT) where the network operates a system of 'private' IP addressing and where address translation takes place when access to the global internet is required
* Network congestion - an 'idle' GPRS terminal will still consume network resource even though there is no exchange of data. This may become a significant overhead for operators if numbers of users grow and they may need to take steps to limit this for low revenue users
* Handset issues - it appears that some of the early handsets (even so-called Class B handsets) do not have the in-built functionality to maintain network sessions when non-data features are used.
Interoperability
Operators and manufacturers are, naturally, somewhat reluctant to provide much detail over the technical issues that might inhibit a smooth roll-out of GPRS service. However, from comments made during various presentations at the Congress, it is clear that most of these arise from the variations of interpretation possible in the SMG31 version of the GPRS standards. These variations of implementation lead to problems with hand-off between cells and problems in timeslot allocation. Both of these difficulties lead to problems in either the establishment of a GPRS session or a dropped call.
There was criticism voiced that there are few published testing scenarios through which operators can prove operational efficiency of various handsets against different networks. In practice, operators have been forced to restrict operation to handset units that, by experience, have been shown to operate satisfactorily.
Additional interoperability issues arise from differences in WAP browser support, although these were not specifically mentioned in detail during the Congress.
Roaming>
GPRS roaming was highlighted by a number of speakers as being of prime importance, especially if business users are to be attracted to the service. Although a small number of inter-network roaming connections are already in place, these are generally private arrangements between individual operators of the same group and cannot be compared with the more or less global roaming arrangements that apply to voice service. The technology that needs to be added to networks to allow data roaming is relatively straightforward; but it is the organisational and contractual issues that appear to be delaying implementation.
In its simplest form, a network can allow data access to a visitor by setting up a local IP connection, providing it can obtain call authorisation and billing information from the home network. However, this would provide a presentation that is linked to the local network data service and would conflict with an overall desire that the user sees a common application presentation regardless of whether he is operating on a home or visited network. This will be especially important where WAP is a primary application interface as the roamer will require access to his home network WAP application set.
The additions required to allow full roaming are a Border Gateway (BG) that provides a secure roaming link out of the network, and a range of Domain Network Servers (DNS) that resolve IP address requirements. The issue holding up development of GPRS roaming revolves around the way in which the networks will then link their border gateways together in order to exchange data.
There are three potential methods of achieving this linkage.
1. Through the public internet. This would be a least cost solution but would be inherently insecure and would not provide a predictable level of service
2. Leased lines. Each operator could maintain a network of leased lines providing direct connection with every other operator with which it has established a GPRS roaming agreement
3. Through a VPN specially constructed and maintained for handling GPRS roaming.
The initial GPRS roaming services have all made use of dedicated leased lines. However, future development is certain to be based on the VPN solution; but the timescale for widespread implementation is uncertain. The GSM Association's International Roaming Expert Group (IREG) has established a set of standards known as Global Roaming Exchange (GRX) which defines protocols to be used by operators and independent 'GRX providers'. Sonera was one of the first organisations to trial GRX functionality and there are a number of others that have announced similar plans. But, at present, there is no real indication of when a viable and widespread service offering will become available.
Other topics
Tariffing, Prepay, and Billing
Only a few presentations dealt directly with revenue recovery.
Operators that have already launched GPRS service have a relatively wide range of tariffs in terms of periodic charges and fees for data quantity. However, with a lack of experience to reflect the amounts of data that users might transfer, the included data quantities are usually quite high; this means that these tariffs are essentially flat rate rather than the supposed volume based. Some operators have instituted tariff schemes that give a choice of WAP-only, or WAP+WEB access.
Ilan Paretsky, Director of Marketing at Comverse, looked at the requirements for developing advanced systems that will provide a range of tariff and billing options, for composite voice and data users, that will include the facility for content-based billing - ie charges associated with the inherent value of the supplied data. It was accepted that there will be consumer resistance to paying for internet derived information where the user has been accustomed to receiving this 'free' in the fixed environment. Although the Camel-3 protocols will support complex billing scenarios, they will not include any element of content value billing and this will need to be supported by independent servers.
With an increasing proportion of cellular users opting for prepay options, there is a lot of interest in developing billing mechanisms that will extend GPRS availability in this area. This will be particularly important if the concept is accepted that the 15-24 year-old age group - big SMS users and predominantly prepay - are to be convinced of the attraction of migrating to GPRS.
Developments In North America
Two presentations, from AT&T, and Golden Bridge Technology/SBC dealt with the evolution of GSM-based wireless data in North America. Despite recent suggestions to the contrary, both speakers were at pains to emphasise a continuing role for EDGE as part of their development strategy towards 3G. Both gave timescales that saw a GSM/GPRS overlay to their respective networks during 2001, followed by an upgrade to EDGE during 2002 and the beginning of UMTS deployment during 2003.
Experience Of Early Implementers
Operator presentations came from:
Amena (Spain)
Blu (Italy)
Omnitel (Lithuania)
T-Mobil (Germany)
Telering (Austria)
Telstra (Australia).
....but little was revealed that was not already in the public domain.
Presentations were limited to reiterations of the basic marketing concepts and detail of standard technical implementation. In response to questions, the speakers were extremely reluctant to talk about GPRS subscriber numbers beyond admitting that early take-up was slow and hinting at numbers '...in the low thousands'.
Acceptance of Advertising
A number of speakers discussed possible user attitudes towards advertising and the potential for this separate source of operator revenue to allow a lower tariff scale for specific groups. There were clear views on the constraints that would need to apply.
* Any advertising must be personalised and relevant to an individual users interests
* It must be optional with the ability to opt-in and opt-out at will
Advertising must be unobtrusive - text and graphics would be acceptable, voice messages unacceptable
* Quantities should be moderate - say around three per day, or 10% of SMS messages
* Advertising must always be free to the recipient and not paid for through wasted airtime.
M-commerce
Although presumably of significant importance to the ongoing development of data services, there was virtually no mention, during the Congress, of m-commerce issues. It would appear that these are currently very much on the back-burner until the lessons of the recent problems in the dot-com world become apparent. <<
- Eric - |
