G3G CDMA Harmonization: Important Links and Wireless Week's Summary
The previous post discussed Qualcomm's bid to establish proprietary (open) control of the architecture of ITU IMT-2000 3G CDMA standards, by threatining to use their IP to block any standard not based on key elements of their synchronous narrowband implementation:
Message 18912506
Important Links
1.) A significant overview of 3G3 in PDF slide format (106 slides):
icr.a-star.edu.sg
2.) ITU overview of 3G3 CDMA (16 pages in RTF format)
web.archive.org
3.) 3G3 Harmonized CDMA Slide Set & Presentation ("3G3 and Its Future")
cdg.org.
4.) CDG Digevent featuring Dr. William C. Y. Lee
Dr. Lee's actual Digevent webcast where he used the slides above and described the evolution of the various CDMA standards, the failure to achieve a single converged CDMA standard, the harmonization initiative that followed, the Network to network interface (NNI) and "hooks and extensions", and differences between the standards, can be viewed here:
cdg.org
5.) OHG 3G3 Technical Framework Proposal (May 28th 1999)
3gpp.org
6.) Wireless Systems Design August 1999 Harmonization Overview
wsdmag.com
>> Piecing Together Global Harmonization
While the industry may never fully harmonize third-generation technologies, the movers and shakers behind the scenes are trying to ensure that future approaches for advancing wireless standards offer customers some semblance of seamless services and interfaces.
Peggy Albright
Wireless Week
January 21, 2002
wirelessweek.com
Last year the term "harmonization"–as in the harmonization of third-generation technologies– surfaced again in the wireless industry. Unlike the concept's earlier heyday during the technology wars of the late 1990s, this time it may come closer to achieving its goals, conservative as they may be.
The industry, which abandoned the ideal of a single global 3G standard during the IMT-2000 battles, once again is talking about harmonization even though the main air interface technologies of interest–wideband-CDMA and CDMA2000–have enough basic differences to ensure they never will be fully harmonized.
Still, it appears that industry movers and shakers have decided that future technologies and approaches for advancing wireless standards can, perhaps, bring some semblance of seamless services and user-interface features to customers, even if the radio networks themselves have small but fundamental differences. All it would take is a commitment from standards-setting camps to come to an agreement to work together and then get started on specific tasks. That process now is taking shape.
The issue of harmonizing 3G technologies was introduced by the CDMA Technology Group in 1998 and led to the creation of the Operators Harmonization Group not long after. Despite participation by companies from both the W-CDMA and CDMA2000 sides, the two camps did not fully merge their IMT-2000 radio air interface specifications.
The OHG did, however, make it possible for W-CDMA and CDMA2000 services to run on either ANSI 41 or GSM MAP core networks. That achievement makes it possible for operators to build either system on either type of core network. It also facilitates roaming because a customer with a dual-mode device can roam between the systems.
Resumption of the harmonization talk in 2002 could add even more converged features as the technologies continue to evolve.
The development is not really a surprise. Early last year, the International Telecommunication Union encouraged the 3G partnership projects to explore ways to harmonize 3G air interface technologies in forthcoming standard enhancements, which are intended to increase bandwidth in the air interface and accommodate more users in a cell site.
The ITU also urged the industry to devise ways to harmonize proposed Internet protocol core network technologies.
Partnering Up
In response to the ITU's request, the Vodafone-chaired OHG last November pulled together representatives from the two standards-setting 3G partnership projects to seek ways to harmonize their respective 3G air interface technology enhancements.
The 3GPP brings together those companies that are advancing global wireless standards based on evolved GSM networks, including W-CDMA. The 3GPP2 brings in groups from North America and Asia that are advancing global specifications for CDMA technologies, such as CDMA2000.
The W-CDMA camp is developing its enhancement, called high-speed downlink packet access, or HSDPA. The CDMA2000 camp is developing CDMA2000 1X evolution for data and voice, called 1xEV-DV.
One motivation for the enhancements is to get higher capacity out of the 3G air interfaces under certain operational modes and usage scenarios so as to enable integrated voice and simultaneous high-speed packet data services, such as video and video-conferencing capabilities.
While the groups are accepting ideas for harmonization, the process will not include those two forthcoming standards. At the November meeting, participants from both partnership projects agreed that both HSDPA and EV-DV, set for publication and then submission to the ITU this spring, are too far along to change.
"We are looking at what could be possible to harmonize in the future because to harmonize the past is very difficult," says Francois Courau, chairman of the 3GPP Technical Specification Group for Radio Access Networks who also represents Alcatel on GSM and UMTS standardization matters.
Courau co-hosted the meeting on behalf of 3GPP along with Ed Tiedemann, vice chairman of the 3GPP2 Technical Specification Group C and senior vice president of engineering at Qualcomm. Tiedemann agrees with Courau on the outcome. "Basically the conclusion is we're not going to be able to affect the current work on HSDPA and EV-DV," he says.
As Courau, Tiedemann and others describe it, the participants decided it was more realistic to focus on harmonizing 3G technology enhancements in the beginning stages of development than to bring to a halt the current efforts that are based on legacy systems. Even so, the decision for the two entities to go forward is notable.
"It will be the first time the two groups will work together on common aspects…I was very surprised by the willingness to cooperate," Courau says.
Bringing Two Camps Together
While final affirmation of the decision from both camps is yet to come, both groups expect that project plans will go through and work will proceed as conceptualized. To make sure their strategy works, they're devising new procedures for exchanging information between the two camps, new ways to ensure proper sanctioning of project results and ways to keep an eye on the project's progress.
Granted, the participants picked their projects carefully. The first issues they plan to tackle will help advance the harmonization of devices through more commonality in hardware platforms and facilitating the use of common components and globalization of services. The initial steps address relatively small improvements but ones the members believe can lead to other areas of harmonization.
The first objectives, for example, are to come up with common channel models and traffic modeling techniques that both technology groups can later use to develop other harmonized parameters, including common physical requirements for terminal design.
"We felt that was an area where we could start. It's not a large step forward in working between the two groups, but it is a step forward," Tiedemann says.
One of the first terminal design issues they will consider is the potential use of multiple input multiple output antenna technologies, called MIMO for short, which is an exciting but relatively new way of increasing capacity by using multiple antennas in the device and in the base station.
But all that work involves the radio access network. Other harmonization work is forthcoming–also relevant to high-speed data access–that looks at how to make the core networks run on common principles, regardless of which camp the network stems from.
That second effort, also advocated by the ITU, is looking at how 3GPP and 3GPP2 can define the architecture of future networks so they are based on Internet protocol and behave more like the Internet than a a circuit-switched system.
While the CDMA- and GSM-based camps are both addressing all-IP networks, the network models they are developing differ. If brought closer together, they could more easily facilitate international roaming, for example, making services easier for the customer.
Much, if not most, of that work will be handled by the Internet Engineering Task Force, which is working with the two partnership projects. The two partnership projects, in fact, should begin joint meetings in the next couple of months to begin planning ways to bring their approaches together.
So does all of this represent a sea change of technology or just relatively minor adjustments? "It's minor tweaking on radio interfaces, quite a bit of work on terminals to globalize services, with the IP network as the other common thread," says Sam Samra, senior director of technical programs at the CDG.
With any luck and continued willingness to join forces, who knows? By the time the industry gets to 4G, which now is in the early formulation stages at the ITU, perhaps harmonization will be the norm, not the exception. <<
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- Eric - |
