Common Radio Resource Management

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SingleRAN

Common Radio Resource Management

Feature Parameter Description

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Notice

The purchased products, services and features are stipulated by the commercial contract made between Huawei and the customer. All or partial products, services and features described in this document may not be within the purchased scope or the usage scope. Unless otherwise agreed by the contract, all statements, information, and recommendations in this document are provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute a warranty of any kind, express or implied.

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Common Radio Resource Management Contents

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1 Introduction ... 1-1

1.1 Scope ... 1-1 1.2 Intended Audience ... 1-1 1.3 Change History ... 1-1

2 Overview of Co-RRM ... 2-1

2.1 Introduction ... 2-1 2.2 Purposes ... 2-1

3 Cell Load Information Sharing ... 3-1

3.1 Common Measurement Procedure ... 3-1 3.2 Cell Load Information ... 3-2

4 Handover Based on Load Enhancement ... 4-1

4.1 UMTS Handover Based on Load Enhancement ... 4-1 4.1.1 Load-Based Inter-RAT Handover Enhancement ... 4-1 4.1.2 Inter-RAT Handover based on Hierarchical Cell Structure Enhancement... 4-2 4.2 GSM Handover Based on Load Enhancement ... 4-2

5 Service Distribution ... 5-1

5.1 UMTS-to-GSM Service Distribution ... 5-1 5.1.1 CS Service Distribution During RRC Setup... 5-1 5.1.2 Service Distribution After RAB Setup ... 5-2 5.2 GSM-to-UMTS Service Distribution ... 5-3

6 Load Balancing ... 6-1

6.1 UMTS Load Balancing ... 6-1 6.1.1 Load Balance During RRC Setup ... 6-1 6.1.2 Load Balancing After RAB Setup ... 6-2 6.2 GSM Load balancing ... 6-3

7 NACC Procedure Optimization... 7-1

8 Engineering Guidelines ... 8-1

9 Parameters ... 9-1

10 Counters ... 10-1

11 Glossary ... 11-1

12 Reference Documents ... 12-1

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Common Radio Resource Management 1 Introduction

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1 Introduction

1.1 Scope

This document describes the common radio resource management (Co-RRM) based on Iur-g interface. It covers information exchange between GSM and UMTS system over on Iur-g interface, GSM/UMTS handover based on load enhancement, GSM/UMTS service distribution, GSM/UMTS load balancing, and UMTS NACC procedure optimization. For ease of description and understanding, this document mainly describes the requirements for candidate cells during the inter-RAT handover between GSM and UMTS.

Before reading this document, you need to learn the handover mechanisms for GSM and UMTS, and the GSM and UMTS interoperability. You are advised to read the following documents: The Handover Feature Parameter Description of the GBSS, the Handover Feature Parameter Description of the RAN, and the Interoperability Between GSM and WCDMA Feature Parameter Description of the GBSS.

1.2 Intended Audience

This document is intended for:

 _{Personnel who are familiar with WCDMA and GSM basics}  _{Personnel who need to understand Co-RRM feature}  _{Personnel who work with Huawei products}

1.3 Change History

This section provides information on the changes in different document versions. There are two types of changes, which are defined as follows:

 _{Feature change: refers to the change in the Co-RRM feature.}

 _{Editorial change: refers to the change in wording or the addition of the information that was not}

described in the earlier version.

Document Issues

The document issues are as follows:

 _{01 (2011-03-30)}  _{Draft A (2010-12-30)}

01 (2011-03-30)

This is the document for the first commercial release of SRAN6.0.

Compared with issue Draft A (2010-12-30) of SRAN6.0, this issue optimizes the description.

Draft A (2010-12-30)

This is the draft of the document for SRAN6.0.

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Common Radio Resource Management 2 Overview of Co-RRM

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2 Overview of Co-RRM

Through cell load information sharing, Common Radio Resource Management (Co-RRM) makes full use of the advantages of both GSM and UMTS. With the Co-RRM feature, radio resources of GSM and UMTS can be managed collectively and efficiently.

2.1 Introduction

The Co-RRM feature utilizes information exchange between GSM and UMTS over the Iur-g interface to support the following functions and mechanisms:

 _{Cell Load Information Sharing}

 _{Handover Based on Load Enhancement}  _{Service Distribution}

 _{Load Balancing}

 _{NACC Procedure Optimization}

Through the internal information exchange, the load information of GSM and UMTS cells can be shared, and the procedure of Network Assisted Cell Change (NACC) can be optimized. Handover based on load enhancement, service distribution, and load balancing are based on the traffic load of GSM/UMTS cells and the characteristics of each network. The main difference between the three functions is the

requirements for candidate cells during inter-RAT handover. The following sections provide the detailed description for each function.

The BSC6900 is a GSM+UMTS multi-mode base station controller (MBSC) of Huawei. It implements the functions of both UMTS RNC and GSM BSC, as shown in Figure 2-1. In this document, the base station controller is referred to as BSC regarding GSM functions and as RNC regarding UMTS functions. Figure 2-1 BSC6900 in Co-RRM

2.2 Purposes

In Co-RRM, several GSM/UMTS interoperability functions are optimized in the BSC6900 to achieve better network convergence and enhance network throughput.

Some major advantages achieved through the Co-RRM feature, utilizing internal information exchange are:

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Common Radio Resource Management 2 Overview of Co-RRM

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 _{The load information of the GSM and UMTS neighboring cells can be shared, which enhances the}

load control capability between GSM and UMTS.

 _{The accuracy of the load information for handover decision between GSM and UMTS is enhanced,}

reducing the risk of ping-pong effect.

 _{The service load can be distributed based on the conditions in the GSM and UMTS networks through}

RRC redirection and service-based inter-RAT handover. This enables the GSM network to handle voice services and the UMTS network to handle high-speed PS services

 _{The service load can be distributed based on the service attributes and the conditions in the GSM and}

UMTS networks through RRC redirection and load-based inter-RAT handover. In this way, the load on the two networks in the same coverage area is increased evenly so the risk of network congestion due to load imbalance is reduced and the total network capacity is enhanced.

 _{The CN does not need to be involved in the GSM/UMTS PS NACC procedure under one BSC6900. In}

this way, the execution time for the NACC procedure is shortened and the PS service handover delay is reduced. In addition, an NACC solution is also provided when the CN does not support the RIM procedure.

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Common Radio Resource Management 3 Cell Load Information Sharing

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3 Cell Load Information Sharing

The load information sharing between GSM and UMTS cells is achieved through a common

measurement procedure in internal information exchange. This involves a procedure through which the BSC obtains the load information of UMTS neighboring cells and a procedure through which the RNC obtains the load information of GSM neighboring cells.

Through load information sharing, the load information of the cells of different systems can be obtained, avoiding unnecessary handover attempts.

3.1 Common Measurement Procedure

The basic procedure behind the cell load information sharing is a BSC6900 internal information exchange mechanism, where the BSC side of the BSC6900 sends a COMMON MEASUREMENT INITIATION REQUEST message to the RNC side and vice versa to initiate the common measurement procedure, requesting the target RNC/BSC to report the load information of its neighboring cells. If the target RNC/BSC supports the common measurement, it responds with a COMMON MEASUREMENT INITIATION RESPOSE message; otherwise, it responds with a COMMON MEASUREMENT

INITIATION FAILURE message.

After a successful common measurement initialization, the target RNC/BSC sends the COMMON MEASUREMENT REPORT message to the source BSC/RNC periodically to report its load information. If the measurement fails to be further performed, for example, when the cell is faulty, blocked, deleted, or deactivated, the common measurement is stopped. In this case, the target RNC/BSC sends a COMMON MEASUREMENT FAILURE INDICATION message to the source BSC/RNC.

Figure 3-1, Figure 3-2, Figure 3-3 and Figure 3-4 show the common measurement procedure. Figure 3-1 Successful common measurement initialization

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Common Radio Resource Management 3 Cell Load Information Sharing

3-2 Figure 3-3 Common measurement reporting procedure

Figure 3-4 Failed common measurement

3.2 Cell Load Information

During the common measurement procedure, load information related to GSM and UMTS cells, is shared between the BSC and RNC sides of the BSC6900. In addition, the GSM cell sends the information that whether it supports inter-RAT handover.

There are three load states: normal, basic congestion, and overload congestion. With uplink direction in GSM as an example, an uplink load lower than GSM uplink basic congestion threshold

(UlLdrThrd2GCell) represents the normal state. An uplink load above this threshold but below the GSM uplink overload congestion threshold (UlOlcThrd2GCell), represents the basic congestion state. An uplink load above this threshold represents the overload congestion state.

The BSC side of the BSC6900 sends the inter-RAT handover support information to indicate whether the CS/PS services can be handed over from a UMTS cell to a GSM cell. The inter-RAT handover support information includes the inter-RAT CS service handover support flag and the inter-RAT PS service handover support flag. If the inter-RAT CS service handover support flag is enabled, the corresponding GSM cell can be the target cell of the inter-RAT CS service handover from a UMTS cell; if the inter-RAT PS service handover support flag is enabled, the corresponding GSM cell can be the target cell of the inter-RAT PS service handover from a UMTS cell.

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Common Radio Resource Management 4 Handover Based on Load Enhancement

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4 Handover Based on Load Enhancement

The handover based on load enhancement function corresponds to the feature MRFD-211404 MBSC Handover based on Load Enhancement.

When the Co-RRM feature is used, the BSC6900 can select the target cell according to the traffic load in the cell before initiating an inter-RAT handover, reducing the ping-pong handover between GSM and UMTS and enhancing the network usage.

4.1 UMTS Handover Based on Load Enhancement

The UMTS handover based on load enhancement function corresponds to the feature WRFD-070004 Load Based GSM and UMTS Handover Enhancement Based on Iur-g.

Through the internal load information sharing mechanism, the load-based inter-RAT handover is enhanced in the UMTS.

 _{In the load-based inter-RAT handover, the UMTS selects the target GSM cell according to the load on}

the GSM neighboring cell and the load difference between the UMTS cell and the GSM neighboring cell.

 _{In the inter-RAT handover based on hierarchical cell structure, the UMTS selects the target GSM cell}

depending on the load on the neighboring cells.

The following paragraphs provide further descriptions of the two handover modes.

4.1.1 Load-Based Inter-RAT Handover Enhancement

When the indication of non-coverage-based handover based on GSM load (MBSCNcovHoOn2GldInd) and the indication of load-based handover based on the load difference between UMTS and GSM (LoadHoOn3G2GldInd) are set to ON, the load-based handover to the GSM cell is triggered when the traffic load on the UMTS cell is high. The RNC performs handover decision based on the load on the neighboring GSM cell and the load difference between the UMTS cell and the neighboring GSM cell. For the CS service, a GSM candidate cell must meet the following conditions:

 _{The cell supports the inter-RAT handover for CS services.}

 _{The load on the cell is lower than the CS outgoing inter-RAT handover GSM load threshold}

(CSHOOut2GloadThd).

 _{The load of UMTS source cell minus the load of the cell is higher than the threshold of CS load}

difference between UMTS and GSM (Mbsc3G2GLdBlcCsDeltaThrd). For the PS service, a GSM candidate cell must meet the following conditions:

 _{The cell supports the inter-RAT handover for PS services.}

 _{The load on the cell is lower than the PS outgoing inter-RAT handover GSM load threshold}

(PSHOOut2GloadThd).

 _{The load of UMTS source cell minus the load of the cell is higher than the threshold of PS load}

difference between UMTS and GSM (Mbsc3G2GLdBlcPsDeltaThrd). The RNC initiates the handover to the best GSM candidate cell.

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Common Radio Resource Management 4 Handover Based on Load Enhancement

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4.1.2 Inter-RAT Handover based on Hierarchical Cell Structure

Enhancement

When the indication of non-coverage-based handover based on GSM load (MBSCNcovHoOn2GldInd) is set to ON, the handover to the GSM cell is triggered when the traffic load on the UMTS cell is high. The RNC performs the handover decision depending on the load on the GSM neighboring cell. For the CS service, a GSM candidate cell must meet the following conditions:

 _{The load on the cell is lower than the CS outgoing inter-RAT handover GSM load threshold}

(CSHOOut2GloadThd).

For the PS service, a GSM candidate cell must meet the following conditions:

 _{The cell supports the inter-RAT handover for PS services.}

 _{The load on the cell is lower than the PS outgoing inter-RAT handover GSM load threshold}

(PSHOOut2GloadThd).

4.2 GSM Handover Based on Load Enhancement

The GSM handover based on load enhancement function corresponds to the feature GBFD-511101 Load Based Handover Enhancement on Iur-g.

When the inter-RAT load handover switch (OutSysLoadHoEn) is set to ON, the load-based handover from GSM to UMTS is triggered if the load on the GSM cell reaches load handover threshold and the Service Handover attribute of the current service is not "handover to UTRAN or cdma2000 shall not be performed".

The BSC checks all the neighboring UMTS cells. If the load of the GSM source cell minus the load of a neighboring UMTS cell is higher than the threshold of CS load difference between UMTS and GSM (G2G3GLdBlcDeltaThrd) and the level of the neighboring UMTS cell exceeds the load handover threshold, the UMTS cell is taken as a candidate cell.

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Common Radio Resource Management 5 Service Distribution

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5 Service Distribution

The service distribution function corresponds to the feature MRFD-211403 MBSC Service Distribution. The GSM and UMTS networks have different characteristics and capabilities with respect to services that can be provided. The GSM network carries CS services and low-rate data services. The UMTS network is characterized by high data rate and large capacity, which ensures the high data rate and short delay of the data services; however, when high CS traffic load runs on the UMTS network, delay is extended for CS services. Therefore, comparing a UMTS network running only data services, system throughput is considerably decreased. To optimize the utilization of resources in the GSM and UMTS networks, service distribution is introduced.

The inter-RAT service distribution is performed in two directions: UMTS to GSM (controlled by the RNC) and GSM to UMTS (controlled by the BSC). As a result of load-based system redirection and handover, the CS services will mainly be handled by the GSM network whereas the high-rate data services will mainly be handled by the UMTS network.

5.1 UMTS-to-GSM Service Distribution

The UMTS-to-GSM service distribution function corresponds to the feature WRFD-070007 GSM and UMTS Traffic Steering Based on Iur-g.

In UMTS-to-GSM service distribution, the users in the UMTS network are handed over to a GSM target cell that is not congested. The UMTS-to-GSM service distribution can be performed in either of the following phases:

 _{CS service distribution during RRC setup: During the RRC setup, the CS AMR services are redirected}

to the GSM cell.

 _{Service distribution after RAB setup: After the RAB is set up, the CS or PS services are handed over to}

the GSM cell.

5.1.1 CS Service Distribution During RRC Setup

If the CS service is initiated during the RRC setup stage and the service distribution and load balancing algorithm switch (MBSCServiceDiffLdbSwitch) is set to SERVICE-BASED, the service distribution is performed as shown in Figure 5-1.

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5-2 Figure 5-1 UMTS-to-GSM service distribution during the RRC setup

When the RRC is redirected, a GSM candidate cell must meet the following conditions:

 _{The GSM cell is in operation.}

 _{The uplink load and the downlink load of the cell are in normal state.}

The RNC initiates the redirection to the best GSM candidate cell. If no cell is suitable among the GSM neighboring cells, the UE accesses the UMTS cell.

5.1.2 Service Distribution After RAB Setup

After RAB setup, if the service distribution and load balancing algorithm switch

(MBSCServiceDiffLdbSwitch) is set to SERVICE-BASED and the Service Handover attribute carried in the assignment request from the MSC is "Handover to GSM should be performed", the service

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5-3 Figure 5-2 UMTS-to-GSM service distribution after RAB setup

For single CS/PS services, the RNC selects the cells that meet the following conditions from the neighboring cells, and then sends the measurement control to the UEs so that the UEs perform the 3C event measurement to those cells.

 _{The cell supports the inter-RAT handover for CS and PS services.}  _{The uplink load and the downlink load of the cell are in normal state.}

If any cell meets the 3C event reporting conditions, the UE reports the 3C event to the RNC, and then this cell is taken as a candidate cell. If there are multiple candidate cells, the RNC initiates the handover to the best GSM candidate cell. If no qualified cell is available among the GSM neighboring cells, the UE is retained in the UMTS cell.

5.2 GSM-to-UMTS Service Distribution

The GSM-to-UMTS service distribution function corresponds to the feature GBFD-511104 GSM and UMTS Traffic Steering Based on Iur-g.

 _{If the inter-RAT load handover switch (}_{InterRatServiceLoadHoSwitch}_{) is set to Cn Service-based}

and the Service Handover attribute carried in the assignment request from the MSC is "handover to UTRAN or cdma2000 should be performed", the BSC imitates the directed retry to the UMTS.

 _{If the inter-RAT load handover switch}_{(InterRatServiceLoadHoSwitch}_{) is set to Service-based, the}

CS traffic in the GSM system is retained in the GSM cell, avoiding the directed retry from the GSM to the UMTS when the Service Handover attribute is "handover to UTRAN or cdma2000 should be performed".

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 _{If the inter-RAT load handover switch (}_{InterRatServiceLoadHoSwitch}_{) is set to Dynamic}

Service/Load-based and the load in the GSM cell is in normal state, that is, the uplink load and downlink load are lower than UlLdrThrd2GCell and DlLdrThrd2GCell respectively, the CS traffic in the GSM system is retained in the GSM cell.

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Common Radio Resource Management 6 Load Balancing

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6 Load Balancing

The load balancing function corresponds to the feature MRFD-211402 MBSC Load Balancing.

In the case of GSM/UMTS co-existence, the traffic loads on the two networks are normally different. For better utilization of the resources in the GSM and UMTS networks, load balancing is introduced to balance the loads between the GSM and UMTS networks, avoiding the situation where one system is overloaded whereas the other one is only lightly loaded.

The BSC6900 enables the redirection and handover between the GSM and UMTS systems based on the load condition and difference in each network. In this way, the two networks in the same coverage area can have similar load conditions, reducing the risk of access congestion.

6.1 UMTS Load Balancing

The UMTS load balancing function corresponds to the feature WRFD-070006 GSM and UMTS Load Balancing Based on Iur-g.

With UMTS load balancing, the CS AMR services and the low-rate PS services are handed over from a UMTS cell to a GSM cell when the GSM cell load is in normal state. The UMTS load balance can be performed in either of the following phases:

 _{Load balancing during RRC setup: During the setup of the RRC connection, the CS AMR services are}

redirected to the GSM cell.

 _{Load balance after RAB setup: After the RAB is set up, the single CS or PS services are handed over}

to the GSM cell.

6.1.1 Load Balance During RRC Setup

If the CS AMR service is initiated during the RRC setup stage and the service distribution and load balancing algorithm switch (MBSCServiceDiffLdbSwitch) is set to LOAD-BASED, the service distribution is performed as shown in Figure 6-1.

Figure 6-1 UMTS load balance during RRC setup

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 _{The uplink load and downlink load in the GSM cell are not in overload congestion state.}  _{The cell supports the inter-RAT handover for CS services.}

 _{The load of UMTS source cell minus the load of the cell is higher than the threshold of CS load}

difference between UMTS and GSM (Mbsc3G2GLdBlcCsDeltaThrd).

The RNC initiates the redirection to the best GSM candidate cell. If no cell is suitable among the GSM neighboring cells, the UE accesses the serving UMTS cell.

6.1.2 Load Balancing After RAB Setup

Figure 6-2 UMTS load balancing after RAB setup

If the service distribution and load balancing algorithm switch (MBSCServiceDiffLdbSwitch) is set to LOAD-BASED and the Service Handover attribute carried in the assignment request from the MSC is "Handover to GSM should be performed", load balancing is performed. The RNC selects the cells that meet the following conditions from the neighboring cells, and then sends the measurement control to the UEs so that the UEs perform the 3C event measurement to those cells.

 _{The uplink load and downlink load in the GSM cell is not in overload congestion state.}

 _{For the CS service, the GSM cell supports incoming inter-RAT handover for CS services and the load}

of UMTS source cell minus the load of the GSM cell is higher than the threshold of CS load difference between UMTS and GSM (Mbsc3G2GLdBlcCsDeltaThrd). For the PS service, the GSM cell

supports incoming inter-RAT handover for PS services and the load of UMTS source cell minus the load of the GSM cell is higher than the threshold of PS load difference between UMTS and GSM (Mbsc3G2GLdBlcPsDeltaThrd).

If any cell meets the 3C event reporting conditions, the UE reports the 3C event to the RNC, and then this cell is taken as a candidate cell. If there are multiple candidate cells, the RNC initiates the handover

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6-3 to the best GSM candidate cell. If no qualified cell is available among the GSM neighboring cells, the UE is retained in the UMTS cell.

6.2 GSM Load balancing

The GSM load balancing function corresponds to the feature GBFD-511103 GSM and UMTS Load Balancing Based on Iur-g.

The load balancing can be enabled by setting the inter-RAT load handover switch

(InterRatServiceLoadHoSwitch) to Load-based. Based on the load in the target UMTS cells, the UEs in the GSM network are handed over to the UMTS cells. During the call setup, the GSM-to-UMTS load balancing is performed through directed retry, as shown in Figure 6-3.

Figure 6-3 GSM load balancing

The BSC performs load balancing when the Service Handover attribute carried in the channel

assignment request from the MSC is "handover to UTRAN or cdma2000 should be performed" and the uplink load and the downlink load on the GSM cell that carry the service are not in normal state. The BSC selects the UMTS neighboring cells that meet the following conditions as the candidate cells:

 _{The UMTS cell is in operation.}

 _{The uplink load and downlink load in the UMTS cell is not in overload congestion state.}  _{The load of GSM source cell minus the load of the cell is higher than the threshold of CS load}

difference between UMTS and GSM (G2G3GLdBlcDeltaThrd).

The BSC initiates the redirection to the best UMTS candidate cell. If no cell is suitable among the UMTS neighboring cells, the UE accesses the GSM cell.

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6-4 If the inter-RAT load handover switch (InterRatServiceLoadHoSwitch) is set to Dynamic

Service/Load-based and the serving cell is in load congestion, the BSC selects a suitable cell according to the preceding procedure for the UE to access.

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Common Radio Resource Management 7 NACC Procedure Optimization

7-1

7 NACC Procedure Optimization

The NACC procedure optimization function corresponds to the feature MRFD-211401 NACC Procedure Optimization, and the feature WRFD-070005 NACC Procedure Optimization Based on Iur-g between GSM and UMTS.

To perform NACC in the PS domain, the UMTS cell needs to obtain the system information related to the GSM cell. If the UMTS cell and the GSM cell are operated by the same BSC6900, system information related to the GSM cell can be obtained through internal information transfer rather than through the core network. This reduces the signaling load on the SGSN and makes the cell reselection operation faster.

In a common NACC procedure, when the RNC needs to obtain the system information related to a GSM cell, it sends a RAN INFORMATION REQUEST message to the SGSN. The SGSN then identifies the BSC that serves the target GSM cell, and then forwards the message to this target BSC. The response message, RAN INFORMATION, from the BSC is sent to the RNC through the SGSN. The signaling procedure is illustrated in Figure 7-1.

Figure 7-1 Normal NACC procedure

In the optimized NACC procedure, the SGSN is not involved. If the UMTS cell and the target GSM cell are operated by the same BSC6900, the RNC sends the INFORMATION EXCHANGE INITIATION REQUEST message tothe BSC through an internal message. In addition, the BSC sends the response message through the internal message. The signaling procedure is illustrated in Figure 7-2.

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Common Radio Resource Management 7 NACC Procedure Optimization

7-2 Figure 7-2 Optimized NACC procedure

When using this optimized NACC procedure, provided by the Co-RRM feature, the SGSN is not involved in the NACC procedure, so the execution time for the NACC procedure is reduced. In addition, the signaling load on the SGSN is reduced.

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Common Radio Resource Management 8 Engineering Guidelines

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8 Engineering Guidelines

This section provides engineering guidelines regarding the configuration of Co-RRM. For details, see the SingleRAN Feature Activation Guide.

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Common Radio Resource Management 9 Parameters

9-1

9 Parameters

Table 9-1 Parameter description

Parameter ID NE MML Command Description CSHOOut2Gloa dThd BSC6900 ADD UCELLINTERRATH ONCOV(Optional) MOD UCELLINTERRATH ONCOV(Optional)

Meaning: This parameter specifies the threshold for 2G load of relocation target, in an inter-RAT handover in CS domain. When the GSM load policy is used, that is, when "NcovHoOn2GldInd" in "SET

UINTERRATHONCOV" is set to ON, a

non-coverage-based handover to a 2G cell is stopped in a non-coverage-based 3G-to-2G handover

procedure if the uplink or downlink normalized load carried in the relocation response message from the 2G system exceeds the value of this parameter. GUI Value Range: 0~100

Actual Value Range: 0~1 Default Value: 80 DlLdrThrd2GCe ll BSC6900 SET GCELLHOINTERRA TLDB(Optional)

Meaning: When the downlink load of a cell is larger than the value of this parameter and is smaller than "2G Cell DL Overload Congest Thred", the downlink of the cell is in the basic congestion status.

GUI Value Range: 1~100 Actual Value Range: 1~100 Default Value: 90 G2G3GLdBlcD eltaThrd BSC6900 SET OTHSOFTPARA(Opt ional)

Meaning: Use this parameter to set Load difference threshold for load-based handovers between GSM and UMTS.

If the load balance between a 2G cell and a 3G cell is greater than the threshold, load balance is triggered. GUI Value Range: 0~200

Actual Value Range: -100~100 Default Value: 110 InterRatService LoadHoSwitch BSC6900 SET GCELLHOINTERRA TLDB(Optional)

Meaning: When this parameter is set to Service-based, the inter-RAT handover is triggered on the basis of the service distribution. In this case, the target cell is selected this parameter is set to Load-based, the inter-RAT handover is triggered on the basis of the load balance. In this case, the target cell is selected

according to the traffic load on the target cell and the load difference between 2G and 3G cells.

When this parameter is set to Dynamic Service/Load based, the target cell is dynamically selected by using the service-based algorithm or the load-based

algorithm according to the traffic load on the cell. When this parameter is set to CN Service-based, the inter-RAT handover decision is made on the basis of the service attribute of the core network.

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9-2 Parameter ID NE MML Command Description

When this parameter is set to OFF, no inter-RAT service handover or inter-RAT load handover in the access state is performed.

GUI Value Range: Service-based(Service-based), Load-based(Load-based), Dynamic-based(Dynamic Service/Load-based), CnService-based(CN

Service-based), OFF(OFF)

Actual Value Range: Service-based, Load-based, Dynamic-based,

CnService-based, OFF Default Value: OFF

LoadHoOn3G2 GldInd

BSC6900 SET

UMBSCCRRM(Optio nal)

Meaning: If the switch is ON, the load difference between 3G cell and target 2G cell will be considered during the load-base handover. If the switch is OFF, the load difference between 3G cell and 2G cell will not be considered.

GUI Value Range: OFF(OFF), ON(ON) Actual Value Range: OFF, ON

Default Value: OFF Mbsc3G2GLdBl

cCsDeltaThrd

BSC6900 SET

Meaning: This parameter defines the load difference threshold between 3G cell and 2G cell when CS service is distributed to 2G. If the load difference between 3G cell and target 2G cell exceeds this parameter value, then the load-based balance of CS service may be performed.

GUI Value Range: -100~100 Actual Value Range: -100~100 Default Value: 10 Mbsc3G2GLdBl cPsDeltaThrd BSC6900 SET UMBSCCRRM(Optio nal)

Meaning: This parameter defines the load difference threshold between 3G cell and 2G cell when PS service is distributed to 2G. If the load difference between 3G cell and target 2G cell exceeds this parameter value, then the load-based balance of PS service may be performed.

GUI Value Range: -100~100 Actual Value Range: -100~100 Default Value: 30 MbscNcovHoO n2GldInd BSC6900 SET UMBSCCRRM(Optio nal)

Meaning: If the switch is ON, the load state of target 2G cell will be considered during Non-covered InterRat handover procedure. If the switch is OFF, the load state of target 2G cell will not be considered. GUI Value Range: OFF(OFF), ON(ON) Actual Value Range: OFF, ON

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MbscServiceDif fLdbSwitch

BSC6900 SET

Meaning: This parameter defines the switch of service distribution and load balancing algorithm. If

SERVICE-BASED is selected, only load state of 2G target cell will be considered. If LOAD-BASED is selected, the difference between the load in the source cell and load in the target 2G cell will be considered in addition. If DYNAMIC-BASED is selected, it will be automatically adjusted to SERVICE-BASED or

LOAD-BASED according the load status of current cell. GUI Value Range: OFF(OFF),

SERVICE-BASED(SERVICE-BASED), LOAD-BASED(LOAD-BASED),

DYNAMIC-BASED(DYNAMIC-BASED) Actual Value Range: OFF, SERVICE-BASED, LOAD-BASED, DYNAMIC-BASED

Default Value: OFF OutSysLoadHo

En

BSC6900 SET

GCELLHOINTERRA TLDB(Optional)

Meaning: This parameter specifies whether to allow the inter-RAT load handover in connection mode (after the assignment is complete).

GUI Value Range: NO(No), YES(Yes) Actual Value Range: NO, YES

Default Value: NO PSHOOut2Gloa dThd BSC6900 ADD UCELLINTERRATH ONCOV(Optional) MOD UCELLINTERRATH ONCOV(Optional)

Meaning: This parameter specifies the threshold for 2G load of relocation target, in an inter-RAT handover in PS domain. When the GSM load policy is used, that is, when "NcovHoOn2GldInd" in "SET

UINTERRATHONCOV" is set to ON, a

non-coverage-based handover to a 2G cell is stopped in a non-coverage-based 3G-to-2G handover

procedure if the uplink or downlink normalized load carried in the relocation response message from the 2G system exceeds the value of this parameter. GUI Value Range: 0~100

Actual Value Range: 0~1 Default Value: 60 UlLdrThrd2GCe ll BSC6900 SET GCELLHOINTERRA TLDB(Optional)

Meaning: When the uplink load of a cell is larger than the value of this parameter and is smaller than "2G Cell UL Overload Congest Thred", the uplink of the cell is in the basic congestion status.

GUI Value Range: 1~100 Actual Value Range: 1~100 Default Value: 90 UlOlcThrd2GCe ll BSC6900 SET GCELLHOINTERRA TLDB(Optional)

Meaning: When the uplink load of a cell is greater than the value, the uplink of the cell is in the overload congestion status.

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GUI Value Range: 1~100 Actual Value Range: 1~100 Default Value: 100

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Common Radio Resource Management 10 Counters

10-1

10 Counters

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Common Radio Resource Management 11 Glossary

11-1

11 Glossary

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Common Radio Resource Management 12 Reference Documents

12-1

12 Reference Documents

[1] Handover Feature Parameter Description of the GBSS [2] Handover Feature Parameter Description of the RAN