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37NC2About This Chapter

37.1 Overview

This topic describes network controlled cell reselection, which is also referred to as network

control mode 2 (NC2). In NC2 mode, the network requests measurement reports from the MS

and controls the cell reselection.

37.2 Availability

This topic describes the availability of NC2. The realization of NC2 depends on the cooperation

of relevant NEs, software, and licenses.

37.3 Technical Description

This topic describes three types of cell reselection modes in NC2: critical cell reselection, cell

load reselection, and general cell reselection.

37.4 Implementation

The implementation of NC2 consists of configuring NC2 and configuring the PCU.

37.5 Maintenance Information

This topic describes the maintenance information on NC2. The information refers to the related

performance counters.

37.6 References

HUAWEI BSC6000 Base Station Subsystem

BSS Feature Description 37 NC2

Issue 01 (2007-09-05) Huawei Technologies Proprietary 37-1

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37.1 Overview

This topic describes network controlled cell reselection, which is also referred to as network

control mode 2 (NC2). In NC2 mode, the network requests measurement reports from the MS

and controls the cell reselection.

Definition

If an MS is in NC2 and packet transfer mode, the network can send a Packet Cell Change Order

message to notify the MS to initiate a cell reselection.

For details of NC0, NC1, and NC2, refer to 36.1 Overview.

Purposes

In NC2 mode, the network orders the MS to reselect a new cell that has better transmission

quality. Compared with the autonomous cell reselection of the MS, the network controlled cell

reselection comprehensively considers the load condition of each cell and automatically adjusts

the loads of the cells.

Terms

None.

Abbreviation

Abbreviation Full Spelling

NC2 Network Control Mode 2

37.2 Availability

This topic describes the availability of NC2. The realization of NC2 depends on the cooperation

of relevant NEs, software, and licenses.

Network Elements Involved

Table 37-1 describes the NEs involved in NC2.

Table 37-1 NEs involved in NC2

MS BTS BSC PCU MSC MGW SGSN GGSN HLR

- - - - - -

NOTE

l -: not involved

l : involved

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BSS Feature Description

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Software Releases

Table 37-2 describes the software versions of GBSS products that support NC2.

Table 37-2 GBSS products and related versionsProduct Version

BSC BSC6000 V900R001C01 and later

releases

PCU PCU G3PCUV300R005C05 and

later releases

Miscellaneous

NC2 is available only when a license is obtained.

NC2 requires the support of an MS.

If an MS supports the NC2 mode, the MS sends a Packet Measurement Report message to trigger

an NC2 procedure.

37.3 Technical Description

This topic describes three types of cell reselection modes in NC2: critical cell reselection, cell

load reselection, and general cell reselection.

Critical Cell Reselection

Critical cell reselection is based on the transmission quality of cells. Based on the UL and DL

receive quality on the Um interface, the PCU determines whether a critical cell reselection should

be performed. Through bit error rates (BERs), the PCU determines the variation in the

transmission quality. The increase in BERs indicates that signal levels decrease or channel

interference increases. Then, the PCU orders the MS to reselect a neighbor cell that has stronger

signal strength.

Cell Load Reselection

In the network, the loads of some cells are heavy, whereas the loads of other cells are light. To

balance the loads of these cells, cell load reselection is performed. In a cell load reselection

procedure, some MSs in heavy-load cells are reselected to light-load cells. In addition, the MSs

in neighbor cells should not be reselected to heavy-load cells. Figure 37-1 shows the cell load

reselection mode.




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Figure 37-1 Cell load reselection mode (1)

A cell with

a heavy load

A cell with

a heavy load

A cell with

a heavy load

A cell witha light load

A cell with

a light load

A cell with

a light load

A cell witha light load

To determine the traffic load of a cell, compare the channel multiplexing rate with the predefined

threshold:

l If the channel multiplexing rate of a cell is higher than the start threshold of load cell

reselection, you can infer that the traffic load of the cell is heavy and load cell reselection

algorithms should be performed.

l If the channel multiplexing rate of a cell is lower than the receiving threshold of cell load

reselection, you can infer that the traffic load of the cell is light. Therefore, some of the

loads of heavy-load cells can be reselected to the cell.

In cell load reselection mode, an MS with overhigh signal levels cannot be reselected to a

neighbor cell. Through the setting of the level threshold of cell load reselection, an MS whose

signal level is lower than the level threshold of cell load reselection can be reselected to a

neighbor cell. Figure 37-2 shows the cell load reselection mode.

Figure 37-2 Cell load reselection mode (2)

Cell A Cell B

Normal

reselection border

Load reselection threshold

Load reselection area

General Cell Reselection

General cell reselection is based on signal levels. If the transmission quality and traffic load of

the serving cell do not trigger cell reselection, the MS is reselected to a neighbor cell that has

stronger signal strength through the general cell reselection procedure.

37.4 ImplementationThe implementation of NC2 consists of configuring NC2 and configuring the PCU.

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37.4.1 Configuring NC2

This topic describes how to configure NC2 on the BSC6000 Local Maintenance Terminal.

37.4.2 Configuring the PCU

This topic describes how to configure NC2 on the PCU Maintenance Terminal.

37.4.1 Configuring NC2

This topic describes how to configure NC2 on the BSC6000 Local Maintenance Terminal.

Procedure

Step 1 Apply for a license and activate the license.

1. Apply for the license of NC2. In theBSC6000V900R001 Exceptional Commercial License

Application Template, specify a value in the Number of the TRX supporting NC2 row

of the Resource control items column. The value indicates the number of TRXs thatsupport NC2.

2. Activate the license on the BSC6000 Local Maintenance Terminal. For details, refer to

Maintaining BSC License.

After the license is activated, the BSC can support NC2 mode. In addition, you need to set the

attributes and parameters of related objects on the BSC6000 Local Maintenance Terminal.

Step 2 On the Management Tree tab page of the BSC6000 Local Maintenance Terminal, right-clickthe target cell and then choose Configure Cell Attributes on the shortcut menu. A dialog box

is displayed, as shown in Figure 37-3.

Figure 37-3 Selecting a cell

Step 3 Double-click the target cell in the Cell view area to add the cell to the Selected cells list.



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Step 4 ClickNext. A dialog box is displayed, as shown in Figure 37-4.

Figure 37-4 Configuring Cells Attributes dialog box

Step 5 ClickSet Cell Properties. A dialog box is displayed, as shown in Figure 37-5.

Step 6 Select the Support NC2 check box. Then, clickOK.

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Figure 37-5 Set Cell Attributes dialog box (NC2)

Step 7 In the dialog box shown in Figure 37-6, clickFinish to complete the configuration.




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Figure 37-6 Configuring Cells Attributes dialog box (NC2)

Step 8 The configuration loading progress dialog box is displayed. When the configuration is complete,the progress dialog box disappears.

----End

37.4.2 Configuring the PCU

This topic describes how to configure NC2 on the PCU Maintenance Terminal.

Procedure

Step 1 Log in to the PCU maintenance terminal through Telnet.

Step 2 On the PCU maintenance terminal, run the pcu cell dynset command to enter thecell dynamic configuration window. Set table number to 12, as shown in Figure 37-7.

Figure 37-7 Cell dynamic configuration window

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Step 3 Set NCO to NC2, as shown in Figure 37-8.

Figure 37-8 Setting NC2 mode

Step 4 The setting is active, as shown in Figure 37-9.

Figure 37-9 Setting NC2 mode result window

----End

37.5 Maintenance Information

This topic describes the maintenance information on NC2. The information refers to the relatedperformance counters.




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Alarms

None.

Counters

Table 37-3 Counters related to NC2

Counter Description

Number of Cell Reselections

Controlled by the Network

The counter Number of Cell Reselections Controlled by the

Network is a cell-level performance counter.

Number of Critical Cell

Reselections Controlled by the

Network

The counter Number of Critical Cell Reselections

Controlled by the Network is a cell-level performance

counter.

Number of Cell LoadReselections Controlled by the

Network

The counter Number of Cell Load Reselections Controlledby the Network is a cell-level performance counter.

Number of General Cell


Network

The counter Number of General Cell Reselections


counter.

Number of Failed Cell


Network

The counter Number of Failed Cell Reselections


counter.

37.6 References

3GPP TS 44.060 V6.12.0

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