Go The structure and key technology of WCDMA system

Source: Internet
Author: User

This article transferred from: http://blog.csdn.net/lele52141/article/details/8498951

WCDMA System Structure:

CN refers to the core network, Utran access network, UE user equipment.

In Utran, Node B refers to the base station, and the RNC refers to the base station controller (or wireless network controller). The interface between the base station and the mobile phone is called UU interface, also known as the empty. The interface between the base station and the RNC is called the Lub interface, and the interface between CS and RNC is called Lu-cs. The interface between PS and RNC is called Lu-ps interface. CS is used to process voice services, and PS is used to process data services. The interface between the RNC and the RNC is called the Lur interface, which is mainly used across the RNC switchover.

WCDMA R99/GSM Network structure:

It can be seen from the figure that the 2G and 3G access network parts are completely different, but they are connected to the same core network. Msc,gmsc is the processing of speech, is our CS domain, SGSN,GGSN is processing data, is the PS domain. The data and voice have been separated in the R99.

Take the telephone as an example, the signal of the cell phone first arrives at the base station, the base station then sends the signal to the RNC inside, the RNC sends the signal to the core network again, the core network plays the function of the exchange (can connect the signal to the fixed network, or other region's route). The access terminal also has MSC, the signal from the MSC to reach the RNC, then to the base station, and then to the cell phone.

Rake Receiver:

Fast fading is due to multipath superposition caused by the signal fading, the performance of signal is strong when weak, rake receiver is a passive resistance to fast fading technology, it will be all the multipath signal received down to the phase superposition of the signal enhancement.

Fast power control of WCDMA

Proximity effect: Two mobile phones are not the same distance from the base station, a near, a far. When the two mobile phones with the same power transmission, the signal on the two mobile phone to the base station strength is certainly not the same, from the base station near the power, away from the base station, the power is weak, this time, from the base station near the user began to call, away from the base station users can not call.

Fast power control can resist fast fading, and solve the problem of near-far effect, power control speed can reach 1500 times/s, the advantages of fast power control are: electricity saving, reduce interference, reduce the near and far effect.

WCDMA Switching-switching

Hard switching exists in GSM and WCDMA, when the cell phone from a cell to B cell, will first cut off a cell, and then connected to the B cell, the connection may have a short break.

Both CDMA and WCDMA can use soft switching, soft switching at a certain time and two cells at the same time, so it will cost a certain amount of resources. Features of soft switching:

1 CDMA System Soft switch, can only be used in the same frequency cell

2 first set up the target cell link, after the end of the old cell link, can avoid the call gap.

3 Soft switching consumes system resources.

Switching between different cells in the same node B can use a softer switch to create two links, allowing the signals to be combined to enhance the signal.

Go The structure and key technology of WCDMA system

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