Re: Ongoing 3G Standards Work (and Issues)
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Cao Shumin, deputy director and senior engineer of Research Institute of Telecom Transmission of MII, graduated from the Electronic Engineering Department of Beijing University of Aeronautics and Astronautics (BUAA) and received her MS in electromagnetic field and microwave technology in 1992. She has been involved in studies of mobile communication standards, systems and technological development strategy for many years. She was the chairman of MPT IMT-2000 Evaluation and Coordination Team, and chairman of ITU-R TG8/1 WG5 (IMT-2000 Radio Interface Specifications). She is presently the vice chairman of ITU-R WP8F, the chairman of CWTS, and the Chief Associate of the technical group of the 3G Mobile Communication R&D Project of China.
There has been a comparatively clear outlook of standardization of IMT-2000, but the evolution and development of the 5 standards of IMT-2000 never stop. Competition among standards continues, with frequent emergence of new key issues. This paper introduces the latest developments of ITU-R in the research of Enhanced IMT-2000 and IMT-2000 System Beyond, the route of evolution of the 2G toward the 3G, and the core network wireless interface technology of the 3G. It will also give analysis to the above key issues on the bases of current situations of the standardization of the ITU and 3GPP and 3GPP2 and the development of the product in operating company and manufacturer.
1. Research on ITU'S Initialization of Enhanced IMT-2000 and IMT-2000 System
The RSPC proposal on IMT-2000 wireless technology, the M.1457 proposal which was formally approved by the general congress of the ITU-R 2000 in May this year, was passed, indicating the completion of the final mission done in November 1999 by ITU-R TG8/1 group. Later on, the newly established ITU-R WP8F started the short-term, mid-term and long-term research in Enhanced IMT-2000 and IMT-2000 Beyond core network, and an investigation on establishing a new research group for enhancing research on the core network of Enhanced IMT-2000 and IMT-2000 Beyond.
The Enhanced IMT-2000 aims at supporting wireless IP and more powerful digital transmission capacity (e.g. greater than 2Mbps) on the bases of new technology used in present IMT-2000. At this moment, such technology is already available and is being standardized, for example, the 1XEV, a cdma-2000-1X enhanced technology proposed by 3GPP2, which is said to be powerful enough to support digital rate higher than 5Mbps.
IMT-2000 Beyond means the long-term evolution (5-10 years) of the IMT-2000, which is called the stage of "the 4G". Since the 3G mobile communication technology is now still at the preliminary stage with no big commercialization, and its large capacity potential being unutilized, it is improper to define it as a new generation. For such doing will be of no good to the development of the 2G and the 3G and even of the whole mobile communication. Therefore, ITU strongly urges not to use the term the 4G mobile communication.
The drafting of detailed requirements and objects of the above two stages was started during the conference held in August. It is planned that by the year 2002, the most basic targets and requirements will be accomplished. At the same time, some new techniques such as adaptive antenna, software radio, wireless IP, are all being studied.
Besides, unified plan is being done to expanded spectrum of IMT-2000 determined by WRC, that is 806-960MHz, 1710-1885MHz and 2500-2690MHz, and the frequency band 2300-2400MHz required by China.
2. The 3G Core-Network Evolves Firstly Based on 2G and a Long-Term Development Direction toward the Whole IP Network.
The developments and evolutions of 3G mobile communication core network can be classified into two stages. The first stage is the network of circuit exchange and packet exchange separation network evolved on the bases of 2G core network (mainly GSM MAP and ANSI-41 network). The standardization in this stage is somehow perfect, and will be largely commercialized around the year 2002. The second stage is a whole IP network structure, and is still in a preliminary stage. Its standardization is estimated to complete in the year 2002, and commercialization will be later than year 2004.
1) The First to Be Commercialized Is the Core Network Based on the Evolution of the 2G Parallel 2) Development of Circuit Switch and Packet Switch
Compared with the whole IP network which is still in the preliminary stage, the first-stage standard of the 3G formulated on the base of the 2G core network GSM MAP and ANSI-41, not only is compatible forwardly to the 2G, but also gives out a smooth transition from service to the network using a comparatively mature technology. So, around year 2002, this structure will certainly become a base for the largely commercialized 3G mobile core network.
This structure features a separated circuit switch service and packet switch service. The 2G and the 3G can share a common core network platform, and links different radio access network (base station sub-system) through different interface. For example, the 99 version of 3GPP links GSM base station through interface A and interface Gb on the base of SGSN/GGSN core network of GSM MSC and GPRS. Meanwhile, it links the WCDMA base station through newly defined Iu-CS and Iu-PS. 3GPP2 is based on IS-95MSC and core network of packet switch node PDSN, and links the base stations of IS-95 and cdma2000-1X through A1, A2, A5, A10, and A11.
There are usually two ways of achieving smooth connection between above-mentioned networks. One is to upgrade the software and hardware of the previous equipment. This certainly requires a potential of the existing equipment for possible upgrading. Generally speaking, only the 2G equipment available in the market this year or even next year has this potential. The second way is to put a demand on 3G equipment for the power of supporting both the 2G and the 3G, which require businessmen to fully consider the transition and connection to the 3G when constructing and planning the 2G network.
2) Present Situations of the Whole IP Network
With the rapid development of Internet, and the combination between IP and mobile communication, IP network and IP service has become a trend of development of the 3G mobile communication. However, because of mobility and limited radio resources in the mobile communication network, there are still no solutions like IP network safety and service quality to solve. Voice service still dominates the present services. The network and service must be smoothly evolved on the bases of the 2G network. This keeps the standardization of the whole IP network at the present preliminary stage. It is generally agreed that a fully matured whole IP standardization will be completed only in the year 2002, and commercialization will possibly be only after 2004. For example, 3GPP originally planned to finish the whole IP standardization in 2000 version, but until now, only the 1999 version has been basically completed, and the standardization of the whole IP in 2000 version has not been started. Since the standardization of the whole IP cannot be done in a short time, 3GPP decides not to use the yearly version any more. Instead, they will adopt version based on contents. 3GPP2 is in the similar situation. Only a framework of the whole IP has been worked out.
On the other hand, the whole IP network is indeed a hot-point in the research of the current 3G mobile communication. Many organizations such as IETF, IPv6 forum, WAP forum and MWIF (multi-media wireless IP forum) and 3G.IP have been emerged and very active in recent two years. These groups joined the 3GPP and/or 3GPP2, together with traditional mobile communication companies, to study and discuss the possible solutions for the whole IP of the 3G mobile communication. Efforts are made to achieve a united whole IP plan for the two 3GPP in order to reach the unification in the core network in the future.
A real whole IP network means a complete IP system from the network to the terminal. Present standardization mainly focuses on the core network (CN), and will gradually extend to radio access network (RAN) and user equipment (UE). The whole IP starts with a clear definition to the whole IP network structure, and separates the transmission, control from service. It is estimated that the structure of the whole IP will be initially formulated by the end of this year.
3. Which Technology Standard Will Dominate and Control in the 3G
Although 5 radio interface standards of IMT-2000 have been established during the Helsinki conference held in November 1999, these standards developed and evolved continuously to form new and enhanced technologies, with some combinations. Figure 2 shows the evolution and transition of several techniques to the different techniques in the 3G mobile communication. It also reflected the trend of technical development.
1) Merging of TDMA and GSM, and the Evolution toward WCDMA/CDMA TDD; Further Integration of the Two CDMA TDD - The GSM network with more than 250 million GSM users is, undoubtedly, a main role in the 3G communication. Most operators will adopt an evolution from GPRS to the WCDMA/CDMA TDD. Besides, in their proposed UWC-136 technology, TDMA (IS-136) operators from North America will adopt TDMA technology same with that in GSM, and relevant core network technology. They will further adopt WCDMA technology. Obviously, three IMT-2000 radio technology: WCDMA, CDMA TDD and UWC-136 will gradually merge in 3GPP.
In the meantime, in 3GPP, the integration of two CDMA TDD (TD-SCDMA 1.28Mcps and TD-CDMA 3.84Mcps) has reached a final stage in which technical regulation a formulated. The work should have accomplished by the end of this year or early next year.
The Release 99 version in June this year by 3GPP has been comparatively stable, and the newly approved (in September) version is more stable and mature. WCDMA will be firstly commercialized in Japan in May 2001, but it does not fully satisfy the latest Release 99 standard. It is estimated that WCDMA will be largely commercially in the second half of 2002. By then, the WCDMA/GSM dual band handset will also be in the market. For CDMA TDD, the TD-SCDMA is highly appraised by more and more companies. Apart from Datang and Siemens, other companies such as Huawei, Motorola and Nortel Network have actively participated in the research and development of the TD-SCDMA. TD-SCDMA is expected to launch its on-spot test-system in the first half of 2001, and the product will be available in 2002. Yet, there is not so many companies showing interests in TD-CDMA of 3.84Mcps.
2) The cdma 2000-1X And Its Extended Technology
The evolution of IS-95 CDMA technology (cdmaOne) toward the 3G will be another major trend. A direct evolution from IS-95A toward cdma 2000-1X will be the strategy adopted by most narrow band CDMA operators. cdma 2000-1X has a capacity one time higher than that of cdmaOne, supporting 144Kbps data rate, and can be fully compatible to IS-95A/B, it is welcome by all the narrow band cdma operators. It appeared in South Korea in winter 2000, and will be gradually commercialized broadly since the second half of 2001.
To improve the competitiveness of cdma 2000-1X, 3GPP2 has began the establishment of the 1X evolution technology (i.e. the 1XEV standard) on the base of cdma 2000-1X. 1XEV is presently classified into two phases:
The first phase: 1XEV-DO(Data Only), based on high data rate (HDR) technology proposed by Qualcomm. The service to be supported is not the voice but HDR at an average rate of 650Kbps and a peak rate of 2.4Mbps. Technical regulations are available in September 2000. Products will be available around 2002.
The second phase: 1XEV-DV(Data and Voice) supports both voice and data service. The highest data rate is greater than 5Mbps. It is estimated that the standardization of 1XEV-DV will be finished by May 2001. Technical appraisal and selection are now carried out with two pending technologies: the LAS-CDMA from China and 1XTREME from Nokia or Motorola.
There are great differences in the opinions among operators and manufacturers toward above two phases of 1XEV technology. Since these two techniques, and the cdma2000-1X came into being within a quite short period of time, it is still hard to say which one will have a bright future commercially and will dominate the market.
From the figure we can see that following cdma2000-1X (or 1XEV), there is other possibility of adopting WCDMA and cdma2000-3X. But people do not expect a prominent future for cdma2000-3X, and there is little possibility of its application.
Therefore, there are several possible technical routes following the cdma2000-1X.
4. Present Situation of the Standardization of the 3G Mobile Communication
In China, the standardization of the 3G communication has always been a key project for CWTS, the research group for standardization in wireless communication. It is very active in ITU's activities and joined the 3GPP and 3GPP2 in May 1999 for many activities in the field of standardization. It promotes the standardization in 3GPP and 3GP2, of the TD-SCDMA and LAS-CDMA technology proposed by China. Simultaneously, it works actively to standardize the major technology that is possibly adopted in China.
Presently, the standardization of TD-SCDMA is busily carried out in 3GPP, and it is expected to finish by the end of this year or early next year. As one of the technologies to be selected in 3GPP2 1XEV-DV, LAS-CDMA is now under appraisal and discussion.
On the other hand, research on the standardization of WCDMA TD-SCDMA, cdma2000-1X core network and radio access network is already started.
CWTS will conduct the standardization according to China's special situation in its development, and it decided not to do the standardization to IS-95B, GSM EDGE and cdma2000-3X, etc.
5. To Develop 2G Mobile Data Service and Nourish the Market of 3G
In terms of service development, the evolution and connection from the 2G to the 3G is smooth. The 3G can offer higher quality service just because it has a more powerful transmission capacity. Therefore, there is no need to deliberately search for the so-called 3G "Killer Application". The first thing is to develop and nourish mobile communication service and its application based on the network of 2G. The 3G mobile communication service should be naturally achieved.
In voice service, the operating company set up a network and the rest for the user is to buy a handset. While in the mobile data service, three conditions are required at the same time: a network with certain data transmission capacity and high quality, rich and attractive content and terminals with easy operation. Co-operations among operators, the manufacturers, ISP and ICP are required, and this takes a longer time to educate and support users.
At present, the mobile data service is in its preliminary stage globally, and is widely viewed as a prominent business. The success of i-mode in Japan gives enlightenment and confidence to the whole world.
The development of the 3G mobile communication can be described as "driven by technique and competition". The final success can be achieved only when "market drive" is included and combined.
There is a rapid increase in short-message service in the recent domestic mobile communication network. This has gradually accepted by users. Although the development slows down when WAP is put in the market on May 17, it mainly caused by little practice, limited terminals, complex operation, poor quality network and low speed, etc. With the overcoming of the above problems, it is believed that WAP will have a successful development. <<
Source: Clipped by S100 and posted (Post 2479) on the "The New Qualcomm - write what you like" thread.
- Eric - |
