R99 and R4 versions of WCDMA

R99

The R99 access section mainly defines a new 5MHz broadband Code division multiple address network per carrier frequency, adopting the key technologies of CDMA, such as power control, soft switching and more soft switching, base station only does baseband processing and spread spectrum, the access system intelligence concentrates on the unified management of RNC, and introduces the protocol and mechanism suitable for packet data transmission. The data rate can support 144kbit/s, 384kbit/s, theoretically up to 2mbit/s. The ATM-based IUB interface is adopted between the base station and the RNC, respectively, and the RNC is connected with the CS domain and the PS domain of the core network respectively through the ATM AAL2 Iu-cs and the AAL5 iu-ps.

In the core network definition process, R99 fully consider the backward-compatible GPRS, its circuit domain and GSM fully compatible, through codec converter to achieve voice from ATM AAL2 to 64K circuit conversion, in order to exchange with Gsmmsc. The group domain still uses the network structure of GPRSSGSN and GGSN, compared with GPRS, the concept of service level is increased, and the QoS of group domain is improved and the bandwidth is increased.

From the system point of view, the system still uses the grouping domain and the circuit domain respectively load and the processing way, respectively accesses the PSTN and the public data network. From a general standpoint, R99 more mature, more suitable for the need to immediately deploy the network of new operators, but also for the GSM/GPRS network with the existing mobile network operators, because they fully consider the existing products backward and investment protection, the current commercial deployment are all adopted R99, the main advantage is: (Computer science)

1. The technology is mature, the risk is small;

2. Multi-vendor supply environment formation;

3. Interconnection and interoperability testing is basically completed;

But also because of backward compatibility, R99 also has the disadvantage of this or that:

1. Due to the consideration of backward compatibility, the core network has lagged behind the access network, the AAL2 voice which has been grouped by the Internet has to be converted into 64K circuit by codec converter, which reduces the voice quality and low utilization rate of the core network transmission resources;

2. The core network is still using outdated TDM technology, although the technology is mature, interoperability and reasonable price, but the future existence of outdated technology, manufacturers follow-up development efforts, insufficient spare parts, new business to keep up with the problem, from the perspective of 5-10-year investment, is still a waste of investment;

3. The packet domain and the circuit domain two network parallel, not only increases the investment, moreover the network management complexity enhancement, the net future maintenance expense is high, the evolution idea is not clear;

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

R4

The network structure of the R99,R4 wireless access network has not changed, changes are only some of the interface protocol features and enhancements, such as the introduction of repeater, to solve complex terrain coverage problems and sectors to reduce the terminal and base station transmission power to improve capacity, Node B synchronization to reduce the system adjacent to the intersection of interference, Reduce the cost of the transmission network, QoS optimization of AAL2 connections on Iub and iur, optimization of RRM (wireless Resource Management), QoS negotiation of Rab (Wireless access bearer) on IU, enhanced RAB support, modification of transmission loading process on Iub, iur and IU; and the core network circuit domain changes greatly , mainly reflected in:

1. The network evolved from TDM Central node switching to a typical packet voice distributed architecture;

2. The network adopts the open structure, the business logic is separated from the bottom load, the voice is grouped, and the Utran and the core network voice load mode are realized by the packet mode.

3. Because of the optimized voice codec converter, the delay of voice packet packet in WCDMA network is improved, and the speech quality is improved, the codec conversion may only be realized on the public network with PSTN, and the utilization of core network transmission resources is improved.

4. At the same time, because the voice uses the statistical multiplex way transmission, compared to TDM 64K static circuit bandwidth allocation, may improve the transmission network efficiency, realizes the network bandwidth dynamic allocation, avoids TDM expansion when needs to repeatedly deploy 2M circuit's cumbersome procedure.

But R4 relative to the R99, also has the shortcoming, mainly manifests in:

1. New protocols and technologies;

2. There is currently no commercial deployment;

3. Interconnection needs to be tested;

4. Basically the same as R99 business;