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WCDMA standard and its three versions

    Newly acquired mobile network operator license, operators, and its decision to deploy UMTS networks are facing the first problem is to choose which version of the standard. 3GPP WCDMA standard after years of effort, there are now R99, R4, R5 finalized in three versions, one of the latest version of the R5 to the completion in June 2002. Three versions of its own unique features.

R99

    R99 access some of the main definition of a new carrier frequency of each 5MHz W-CDMA access network, the adoption of the power control, soft handoff and soft handoff key technologies such as CDMA, baseband processor and spread-spectrum base stations only, Intelligent Access System RNC focused on unified management, the introduction of a suitable packet data transmission protocol and mechanisms to support data rate 144Kbit / s, 384Kbit / s, in theory, up to 2Mbit / s. Between base stations and RNC-based ATM's Iub interface, RNC, respectively, of the ATM AAL2 based Iu-CS and Iu-PS of AAL5 separately with the CS core network domain and PS domain linked.

    Net at the core of the process of definition, R99 gives full consideration to the backward-compatible GPRS, and GSM circuit domain is fully compatible codec converter through the implementation of voice ATM AAL2 to 64K from the conversion circuit in order to exchange GSMMSC. Packet domain is still used GPRSSGSN and GGSN network structure, compared with the GPRS, an increase of service level concept, grouping domain ability to improve operations quality assurance, bandwidth increase.

    From the system perspective, the system is still used for packet and circuit domain domain separately deal with the manner and bearing, respectively, access to PSTN and public data network. From the general point of view, R99 relatively sophisticated than necessary for the immediate deployment of new network operators, but also apply to have the GSM / GPRS networks, both mobile network operators, because of its full account of the existing products to Under the compatibility and investment protection, the current use of commercial deployment of all the R99, its main advantage is that:

     1. Technology is mature, the risk of small;

     2. Multi-vendor environment for the formation of supply;

     3. Basically completed interoperability testing;

     But are also taken into account because the downward-compatible, R99 also exist one way or another disadvantage:

     1. Core network because of the backward-compatible, and its development lags behind the access network, access network has been of the AAL2 packet voice codec must first go through the converter into a 64K circuit, reducing the voice quality, core network transmission resource utilization low;

     2. Net is still the core of the use of outdated TDM technology, although the technology is mature, interoperability, and the prices reasonable, but the future existence of technical obsolescence, manufacturers inadequate follow-up development, lack of spare parts, new business can not keep up, from 5-10 year investment perspective, it is still wasteful investment;

     3. Packet Domain and circuit domain, two networks in parallel, not only an increase in investment, and enhance the complexity of network management, network maintenance costs of the next higher, the evolution of ideas is not clear;

    4. Network Intelligence is still based on the node, the whole network deployment of new business need to upgrade-by-point, time-consuming and costly.