Wcdma for umts radio access for third genergation mobile communacations phần 3 doc

The cdma2000 multicarrier option is covered in more detail in Chapter 14, as standardised by 3GPP2. 4.5.4 TR46.1 The WIMS W-CDMA was not based on work derived from an existing second generation technology but was a new third generation technology proposal with no direct link to any second generation standardisation. It was based on the constant processing gain principle with a high number of multicodes in use, thus showing some fundamental differences, but also a level of commonality, with WCDMA technology in other forums. 4.5.5 WP-CDMA WP-CDMA (Wideband Packet CDMA) resulted from the convergence between W-CDMA N/A of T1P1 and WIMS W-CDMA of TR46.1 in the US. The main features of the WIMS W-CDMA proposal were merged with the principles of W-CDMA N/A. The merged proposal was submitted to the ITU-R IMT-2000 process towards the end of 1998, and to the 3GPP process at the beginning of 1999. Its most characteristic feature, compared with the other WCDMA-based proposals, was a common packet mode channel operation for the uplink direction, but there were also a few smaller differences. 4.6 Creation of 3GPP As similar technologies were being standardised in several regions around the world, it became evident that achieving identical specifications to ensure equipment compatibility globally would be very difficult with work going on in parallel. Also, having to discuss similar issues in several places was naturally a waste of resources for the participating companies. Therefore, initiatives were made to create a single foru m for WCDMA standardisation for a common WCDMA specification. The standardisation organisations involved in the creation of the 3 rd Generation Partner- ship Project (3GPP) [9] were ARIB (Japan), ETSI (Europe), TTA (Korea), TTC (Japan) and T1P1 (USA). The partners agreed on joint efforts for the standardisation of UTRA, now standing for Universal Terrestrial Radio Access, as distinct from UTRA (UMTS Terrestrial Radio Access) from ETSI, also submitted to 3GPP. Companies such as manufacturers and operators are members of 3GPP through the respective standardisation organisation to which they belong, as illustrated in Figure 4.2. Later during 1999, CWTS CWTS (the China Wireless Telecommunication Standard Group) also joined 3GPP and contributed technology from TDSCDMA, a TDD-based CDMA third generation technology already submitted to ITU-R earlier. Figure 4.2. 3GPP organisational partners Background and Standardisation of WCDMA 67 3GPP also includes market representation partners: GSM Association, UMTS Forum, Global Mobile Suppliers Association, IPv6 Forum and Universal Wireless Communications Consortium (UWCC). The work was initiated formally at the end of 1998 and the detailed technical work was started in early 1999, with the aim of having the first version of the common specification, called Release ’99, ready by the end of 1999. Within 3GPP, four different technical specification groups (TSGs) were set up as follows:  Radio Access Network TSG;  Core Network TSG;  Service and System Aspects TSG;  Terminals TSG. Within these groups the one most relevant to the WCDMA technology is the Radio Access Network TSG (RAN TSG), which has been divided into four different working groups as illustrated in Figure 4.3. The RAN TSG will produce Release ’99 of the UTRA air interface specification. The work done within the 3GPP RAN TSG working groups has been the basis of the technical description of the UTRA air interface covered in this book. Without such a global initiative, this book would have been forced to focus on a single regional specification, though with many similarities to those of other regions. Thus, the references throughout this book are to the specification volumes from 3GPP. During the first half of 1999 the inputs from the various participating organisations were merged in a single standard, leaving the rest of the year to finalise the detailed parameters for the first full release, Release ’99, of UTRA from 3GPP. The member organisations have undertaken individually to produce standard publications based on the 3GPP specification. Thus, for example, the Release ’99 UMTS specifications from ETSI are identical to the Release ’99 specifications produced by 3GPP. The latest specifications can be obtained from 3GPP [9]. During 2000, further work on GSM evolution was moved from ETSI and other forums to 3GPP, including work on GPRS and EDGE. A new TSG, TSG GERAN was set up for this purpose. Figure 4.3. 3GPP RAN TSG working groups 68 WCDMA for UMTS 4.7 How does 3GPP Operate? In 3GPP the work is organised around work items, which basically define the justification and objective for a new feature. For a smaller topic there need be only a single work item in one working group if the impacts are limited to that group, or at least are mainly for the specifications under the responsibility of that group. For bigger items, such as HSDPA, there were work tasks done for each of the four RAN working groups and these work tasks were under a common work item, a building block, named HSDPA. Of the currently on-going items, MBMS is a having a feature-level description, as that is also covering other groups than TSG RAN, and, respectively, TSG RAN is having a work item as a building block for the feature. The work item sheets also usually contain the specifications to be impacted as well as the expected schedule of the work the latter is usually rather optimistic though. A work item needs to have four supporting companies but also it needs to have justification that can be agreeable at the respective TSG RAN level. (Note that some variations in the way of working exist between TSGs). For a larger topic, quite often a feasibility study (or study item in TSG RAN) is needed before the decision of actually creating a work item. A feasibility study will simply focus on the pain vs. gain ratio of the new feature, comparing the advantages and the resulting impacts on the equipment and existing features (the latter is known as backwards compatibility). For each work item a raporteur is nominated, who has the responsibility of coordinating the work and reporting the progress from WGs to TSG level. At TSG level, every meeting (called a plenary) monitors progress every three months and makes any necessary synchronisation between working groups and TSGs. Sometimes a work item is determined not to have reached the expected target and it may be altered or removed from the work program. Once the work item is completed in all working groups, Change Requests (CRs) are brought to the plenary for approval. CRs contain the changes needed in each particular specification and once the plenary level approval is obtained, the specification will be updated to a new version with the changes resulting from the new feature. The simplified illustration of the process from feasibility study to specification finalisation is shown in Figure 4.4. The latest work item descriptions can be found from [9]. Figure 4.4. Example of 3GPP standardisation process Background and Standardisation of WCDMA 69 Creation of the specification does not necessarily mean that everything is 100% completed. Typically, some meeting rounds are then taken for potential corrections, which usually emerge as implementations proceed and details are being verified in implementation and testing. The CRs are used to introduce the corrections, they are agreed in working groups and, once approved by the following TSG plenary meeting, the CRs are then include d in the specification. 4.8 Creation of 3GPP2 Work done in TR45.5 and TTA was merged to form 3GPP2, focused on the development of cdma2000 Direct-Sequence (DS) and Multicarrier (MC) mode for the cdma2000 third generation component. This activity has been running in parallel with the 3GPP project, with participation from ARIB, TTC and CWTS as member organisations. The focus shifted to MC-mode after global harmonisation efforts, but later work started to focus more on the narrowband IS-95 evolution, as reflected in the IS-2000 standards series. 4.9 Harmonisation Phase During 1999, efforts were made to bring further harmonisation and convergence between the CDMA-based third generation solutions. For the 3GPP framework the ETSI, ARIB, TTA and T1P1 concepts had already been merged to a single WCDMA specification, while cdma2000 was still on its own in TR45.5. Eventually, the manufacturers and operators agreed to adopt a harmonised global third generation CDMA standard consisting of three modes: Multicarrier (MC), Direct Spread (DS) and Time Division Duplex (TDD). The MC mode was based on the cdma2000 multicarrier option, the DS mode on WCDMA (UTRA FDD), and the TDD mode on UTRA TDD. The main technical impacts of these harmonisation activities were the change of UTRA FDD and TDD mode chip rate from 4.096 Mcps to 3.84 Mcps and the inclusion of a common pilot for UTRA FDD. The work in 3GPP2 focused on the MC mode, and the DS mode from cdma2000 was abandoned. Eventually, the work in 3GPP2 resumed on the 1.28 Mcps evolution and development of the MC mode has been stopped. The result is that globally there is only one Direct Spread (DS) wideband CDMA standard, WCDMA. 4.10 IMT-2000 Process in ITU In the ITU, recommendations have been developed for third generation mobile commu- nications systems, the ITU terminology being called IMT-2000 [10], formerly FPLMTS. In the ITU-R, ITU-R TG8/1 has worked on the radio-dependent aspects, while the radio- independent aspects have been covered in ITU-T SG11. In the radio aspects, ITU-R TG8/1 received a number of different proposals during the IMT-2000 candidate submission process. In the second phase of the process, evaluation results were received from the proponent organisations as well as from the other evaluation groups that studied the technologies. During the first half of 1999 recommendation IMT.RKEY, which describes the IMT-2000 multimode concept, was created. 70 WCDMA for UMTS The ITU-R IMT-2000 process was finalised at the end of 1999, when the detailed specification (IMT-RSCP) was created and the radio interface specifications were approved by ITU-R [11]. The detailed implementation of IMT-2000 will continue in the regional standards bodies. The ITU-R process has been an important external motivation and timing source for IMT-2000 activities in regional standards bodies. The requirements set by ITU for an IMT-2000 technology have been reflected in the requirements in the regional standar ds bodies, for example in ETSI UMTS 21.01 [5], in order for the ETSI submission to fulfil the IMT-2000 requirements. The ITU-R interaction between regional standardisation bodies in the IMT-2000 process is reflected in Figure 4.5. The ITU-R IMT-2000 grouping, with TDMA- and CDMA-based groups, is illustrated in Figure 4.6. The UTRA FDD (WCDMA) and cdma2000 are each part of the CDMA Figure 4.5. ITU-R IMT-2000 grouping Figure 4.6. Relationship of ITU-R to the regional standards bodies Background and Standardisation of WCDMA 71 interface, as CDMA Direct Spread and CDMA Multicarrier respectively. UWC-136 and DECT are part of the TDMA-based interface in the concept, as TDMA Single Carrier and TDMA Multicarrier respectively. The TDD part in CDMA consists of UTRA TDD from 3GPP and TD-SCDMA from CWTS. For the FDD part in the CDMA interface, harmonisa- tion has been completed, and the harmonisation process for the CDMA TDD modes within 3GPP resulted in the 1.28 Mcps TDD being included in the 3GPP Release 4 specifications, completed 03/2001. 4.11 Beyond 3GPP Release ’99 Upon completion of the Release ’99 specifications, work will concentrate on specify ing new features as well as making the necessary corrections to Release 1999. Typically such corrections arise as implementation proceeds and test systems are updated to include the latest changes in the specifications. As experience in various forums has shown, a major step forward in system capabilities with many new features requires a phasing-in period for the specifications. Fortunately, the main functions have been verified in the various test systems in operation since 1995, but only the actual implementation will reveal any errors and inconsistencies in the fine detail of the specifications. In 3GPP the next version of the specifications was originally considered as Release 2000, but in the meantime the Release naming was adjusted, so that the next release in March 2001 was called Release 4. Release 4 cont ained only minor adjustments with respect to Release 1999. Bigger items that were included in Release 5 were High-Speed Downlink Packet Access (HSDPA) and IP-based transport layer, see Chapters 11 and 5 respectively. Release 5 was completed 03/2002 for the WCDMA radio aspects. Release ’99 specifications have a version number starting with 3 while Release 4 and 5 specifications have version numbers starting logically with 4 and 5 respectively. On the TDD side, the narrowband (1.28 Mcps) TDD mode originally from CWTS (China) was included in 3GPP Release 4. The 1.28 Mcps UTRA TDD mode, or TD-SCDMA, is covered in Chapter 13. Besides the IP-based transport option in Release 5 the protocols developed by the Int ernet Engineering Task Force (IETF) have also influenced the WCDMA specifications. Release 4 specifications contain robust IP header compression suitable for cellular transmission to enable an efficient Voice over IP (VoIP) service. The next step in the evolution is Release 6, which now has first versions of the specifications available (RAN side), but all features are currently scheduled to be available by 2H/2004. For Release 6, work has been done, e.g., on Multimedia Broadcast Multicast Service (MBMS), feasibility of HSDPA-related enhancements for uplink, radio resource management supporting measurements for beamforming and on other features to enhance the system performance . Work will then continue for Release 7. The exact timing for Release 7 has not been fixed yet, but it is expected to be towards the end of 2005. Which Release a particular feature will end up in will be determined only once the feature is mature enough to enable a change request to be written for the specifications. 72 WCDMA for UMTS References [1] Pajukoski, K. and Savusalo, J., ‘Wideband CDMATest System’, Proc. IEEE Int. Conf. on Personal Indoor and Mobile Radio Communications, PIMRC’97, Helsinki, Finland, 1–4 September 1997, pp. 669–672. [2] Nikula, E., Toskala, A., Dahlman, E., Girard, L. and Klein, A., ‘FRAMES Multiple Access for UMTS and IMT-2000’, IEEE Personal Communications Magazine, April 1998, pp. 16–24. [3] Klein, A., Pirhonen, R., Sko ¨ ld, J. and Suoranta, R., ‘FRAMES Multiple Access Mode 1 – Wideband TDMA with and without Spreading’, Proc. IEEE Int. Conf. on Personal Indoor and Mobile Radio Communications, PIMRC’97, Helsinki, Finland, 1–4 September 1997, pp. 37–41. [4] Ovesjo ¨ , F., Dahlman, E., Ojanpera ¨ , T., Toskala, A. and Klein, A., ‘FRAMES Multiple Access Mode 2 – Wideband CDMA’, Proc. IEEE Int. Conf. on Personal Indoor and Mobile Radio Commu- nications, PIMRC’97, Helsinki, Finland, 1–4 September 1997, pp. 42–46. [5] Universal Mobile Telecommunications System (UMTS), Requirements for the UMTS Terrestrial Radio Access System (UTRA), ETSI Technical Report, UMTS 21.01 version 3.0.1, November 1997. [6] Universal Mobile Telecommunications System (UMTS), Selection Procedures for the Choice of Radio Transmission Technologies of the UMTS, ETSI Technical Report, UMTS 30.03 version 3.1.0, November 1997. [7] Universal Mobile Telecommunications System (UMTS), UMTS Terrestrial Radio Access System (UTRA) Concept Evaluation, ETSI Technical Report, UMTS 30.06 version 3.0.0, December 1997. [8] ETSI Press Release, SMG Tdoc 40/98, ‘Agreement Reached on Radio Interface for Third Generation Mobile System, UMTS’, Paris, France, January 1998. [9] http://www.3GPP.org [10] http://www.itu.int/imt/ [11] ITU Press Release, ITU/99-22, ‘IMT-2000 Radio Interface Specifications Approved in ITU Meeting in Helsinki’, 5 November 1999. Background and Standardisation of WCDMA 73 5 Radio Access Network Architecture Fabio Longoni, Atte La ¨ nsisalmi and Antti Toskala 5.1 System Architecture This chapter gives a wide overview of the UMTS system architecture, including an introduction to the logical network elements and the interfaces. The UMTS system utilises the same well-known architecture that has been used by all main second generation systems and even by some first generation systems. The reference list contains the related 3GPP specifications. The UMTS system consists of a number of logical network elements that each has a defined functionality. In the standards, network elements are defined at the logical level, but this quite often results in a similar physical implementati on, especially since there are a number of open interfaces (for an interface to be ‘open’, the requirement is that it has been defined to such a detailed level that the equipment at the endpoints can be from two different manufacturers). The network elements can be grouped based on similar functionality, or based on which sub-network they belong to. Functionally the network elements are grouped into the Radio Access Network (RAN, UMTS Terrestrial RAN ¼ UTRAN) that handles all radio-related functionality, and the Core Network, which is responsible for switching and routing calls and data connections to external networks. To complete the system, the User Equipment (UE) that interfaces with the user and the radio interface is defined. The high-level system arch itecture is shown in Figure 5.1. From a specification and standardisation point of view, both UE and UTRAN consist of completely new protocols, the design of which is based on the needs of the new WCDMA radio technology. On the contrary, the definition of Core Network (CN) is adopted from GSM. This gives the system with new radio technology a global base of known and rugged CN technology that accelerates and facilitates its introduction, and enables such competitive advantages as global roaming. Another way to group UMTS network elements is to divide them into sub-networks. The UMTS system is modular in the sense that it is possible to have several network elements of the same type. In principle, the minimum requirement for a fully featured and operational WCDMA for UMTS, third edition. Edited by Harri Holma and Antti Toskala # 2004 John Wiley & Sons, Ltd ISBN: 0-470-87096-6 network is to have at least one logical network element of each type (note that some features and consequently some network elements are optional). The possibility of having several entities of the same type allows the division of the UMTS system into sub-networks that are operational either on their own or together with other sub-networks, and that are distin- guished from each other with unique identities. Such a sub-network is called a UMTS PLMN (Public Land Mobile Network). Typically one PLMN is operated by a single operator, and is connected to othe r PLMNs as well as to other types of network, such as ISDN, PSTN, the Internet, and so on. Figure 5.2 shows elements in a PLMN and, in order to illustrate the connections, also external networks. The UTRAN architecture is presented in Section 5.2. A short introduction to all the elements is given below. The UE consists of two parts:  The Mobile Equipment (ME) is the radio terminal used for radio communication over the Uu interface.  The UMTS Subscriber Identity Module (USIM) is a smartcard that holds the subscriber identity, performs authentication algorithms, and stores authentication and encryption keys and some subscription information that is needed at the terminal. UTRAN also consists of two distinct elements:  The Node B converts the data flow between the Iub and Uu interfaces. It also participates in radio resource management. (Note that the term ‘Node B’ from the corresponding Figure 5.1. UMTS high-level system architecture Figure 5.2. Network elements in a PLMN 76 WCDMA for UMTS [...]... Aspects and Principles 3GPP Technical Specification 25. 431 UTRAN Iub Interface: Layer 1 3GPP Technical Specification 25. 432 UTRAN Iub Interface: Signalling Transport 3GPP Technical Specification 25. 433 UTRAN Iub Interface: NBAP Signalling 3GPP Technical Specification 25. 434 UTRAN Iub Interface: Data Transport and Transport Signalling for CCH Data Streams 3GPP Technical Specification 25. 435 UTRAN Iub Interface:... the WCDMA air interface 5.7 UMTS Core Network Architecture and Evolution While the UMTS radio interface, WCDMA, represented a bigger step in the radio access evolution from GSM networks, the UMTS core network did not experience major changes in the 3GPP Release ’99 specification The Release ’99 structure was inherited from the GSM core network and, as stated earlier, both UTRAN and GERAN based radio access. .. perform processing in an MGW, e.g for echo cancellation An overview of the different elements and their interfaces can be found in [24] and further details of the core network protocols in [25] WCDMA for UMTS 98 References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [ 13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [ 23] [24] [25] 3GPP Technical Specification 25.401 UTRAN Overall Description 3GPP... General protocol model for UTRAN terrestrial interfaces 5 .3. 3 Vertical Planes 5 .3. 3.1 Control Plane The Control Plane is used for all UMTS- specific control signalling It includes the Application Protocol (i.e RANAP in Iu, RNSAP in Iur and NBAP in Iub), and the Signalling Bearer for transporting the Application Protocol messages The Application Protocol is used, among other things, for setting up bearers... the GTP tunnel requires only an identifier for the tunnel, and the IP addresses for both directions, and these are already included in the RANAP RAB Assignment messages The same information elements that are used in Iu CS for addressing and identifying the AAL2 signalling are used for the User Plane data in Iu CS Radio Access Network Architecture 85 5.4.2 .3 Iu PS User Plane Protocol Stack In the Iu... Location Measurement Unit (LMU) control  Fault management Radio Access Network Architecture 93 5.5.2.2 Dedicated NBAP When the RNC requests the first radio link for one UE via the C-NBAP Radio Link Set-up procedure, the Node B assigns a traffic termination point for the handling of this UE context, and every subsequent signalling related to this mobile is exchanged with dedicated NBAP (D-NBAP) procedures... the mapping of Radio Access Bearer parameters into air interface transport channel parameters, the handover decision, and outer loop power control, are executed in the SRNC The SRNC may also (but not always) be the CRNC of some Node B used by the mobile for connection with UTRAN One UE connected to UTRAN has one and only one SRNC WCDMA for UMTS 80 Figure 5.4 Logical role of the RNC for one UE UTRAN.. .Radio Access Network Architecture 77 3GPP specifications is used throughout Chapter 5 The more generic term ‘Base Station’ used elsewhere in this book means exactly the same thing.)  The Radio Network Controller (RNC) owns and controls the radio resources in its domain (the Node Bs connected to it) RNC is the service access point for all services UTRAN provides the CN, for example, management... for CCH Data Streams 3GPP Technical Specification 25.425 UTRAN Iur Interface: User Plane Protocols for CCH Data Streams 3GPP Technical Specification 25.426 UTRAN Iur and Iub Interface Data Transport and Transport Signalling for DCH Data Streams 3GPP Technical Specification 25.427 UTRAN Iur and Iub Interface User Plane Protocols for DCH Data Streams 3GPP Technical Specification 25. 430 UTRAN Iub Interface:... by O&M actions 5 .3. 3.2 User Plane All information sent and received by the user, such as the coded voice in a voice call or the packets in an Internet connection, are transported via the User Plane The User Plane includes the Data Stream(s), and the Data Bearer(s) for the Data Stream(s) Each Data Stream is characterised by one or more frame protocols specified for that interface 5 .3. 3 .3 Transport Network . Report, UMTS 30 . 03 version 3. 1.0, November 1997. [7] Universal Mobile Telecommunications System (UMTS) , UMTS Terrestrial Radio Access System (UTRA) Concept Evaluation, ETSI Technical Report, UMTS 30 .06. and EDGE. A new TSG, TSG GERAN was set up for this purpose. Figure 4 .3. 3GPP RAN TSG working groups 68 WCDMA for UMTS 4.7 How does 3GPP Operate? In 3GPP the work is organised around work items,. Mobile Radio Commu- nications, PIMRC’97, Helsinki, Finland, 1–4 September 1997, pp. 42–46. [5] Universal Mobile Telecommunications System (UMTS) , Requirements for the UMTS Terrestrial Radio Access