Extended range

RAN

Extended Range

Issue 01

Date 2009-03-30

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RANExtended Range

About This Document

About This Document

AuthorPrepared by Fu Song Date 2008-12-26

Edited by Xin Lichen Date 2009-01-04

Reviewed by Ren Wei and Zhang Jianhua Date 2009-01-04

Translated by Wang Xiaofen Date 2009-01-15

Tested by Hu Zengqiang Date 2009-02-15

Approved by Li Qiang Date 2009-03-30

Issue 01 (2009-03-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co.,

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RANExtended Range

Contents

Contents

1 Change History...........................................................................1-22 Introduction...............................................................................2-2

2.1 Background.....................................................................................................................................................2-22.2 Introduction....................................................................................................................................................2-22.3 Availability......................................................................................................................................................2-2

2.3.1 Intended Audience.................................................................................................................................2-22.3.2 Impact....................................................................................................................................................2-22.3.3 Network Element Involved...................................................................................................................2-22.3.4 Software Versions..................................................................................................................................2-22.3.5 Protocol Compliance.............................................................................................................................2-2

3 Technical Description..................................................................3-23.1 RACH Subchannel.........................................................................................................................................3-23.2 Subchannel-Based Management....................................................................................................................3-23.3 Time Slice Allocation Policy..........................................................................................................................3-2

4 Implementing Extended Range....................................................4-24.1 Enabling Extended Range..............................................................................................................................4-2

4.1.1 Hardware Requirements........................................................................................................................4-24.1.2 Configuring Extended Range................................................................................................................4-24.1.3 Verifying the Enabling..........................................................................................................................4-2

4.2 Disabling Extended Range.............................................................................................................................4-24.2.1 Disabling Extended Range....................................................................................................................4-24.2.2 Verifying the Disabling.........................................................................................................................4-2

5 Extended Range Parameters.......................................................5-25.1 Description.....................................................................................................................................................5-25.2 Values and Ranges..........................................................................................................................................5-2

6 Maintenance Information............................................................6-26.1 Counters..........................................................................................................................................................6-26.2 Alarms.............................................................................................................................................................6-2

7 Reference Documents.................................................................7-2


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1 Change History

The change history provides information on the changes in different document versions.

Document and Product VersionsDocument Version RAN Version

01 (2009-03-30) 11.0

Draft (2009-03-10) 11.0

Draft (2009-01-15) 11.0

The available time of each feature is subject to the RAN product roadmap.

There are two types of changes, which are defined as follows:

Feature change: refers to the change in the extended range feature. Editorial change: refers to the change in the information that was inappropriately

described or the addition of the information that was not described in the earlier version.

01 (2009-03-30)This is the document for the first commercial release of RAN11.0.

Compared with draft (2009-03-10), this issue optimizes the description.

Draft (2009-03-10)This is the second draft of the document for RAN11.0.

Compared with draft (2009-01-15), draft (2009-03-10) optimizes the description.

Draft (2009-01-15)This is the initial draft of the document for RAN11.0.

This is a new document.


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2 Introduction

2.1 BackgroundMobile communications has penetrated into every aspect of social life. People expect to communicate with each other anytime, anywhere.

Traditional wireless services are provided mainly in densely populated areas. Therefore, the research on radio propagation models for areas such as urban areas, suburban areas, and open areas is sufficient. In comparison, the research on radio propagation models for thinly populated and remote areas such as the sea, grasslands, and deserts is insufficient.

With the economy growing at a healthy rate, industrial sectors such as coastal fishery, grassland tourism, and desert greening are rapidly developing and the demands for mobile communications are also increasingly improved. Telecom operators are facing the challenge of expanding their services to rural and remote areas.

In the initial stage of WCDMA, hardware resources and implementation difficulty limit the coverage radius of a cell to 30 km. In some special terrains such as islands, coastlines, and grasslands, the coverage of 30 km cannot meet the actual demands. Therefore, operators require a extended range solution.

Huawei WCDMA extended range solution can increase the coverage several times that of a traditional cell. The base station adopting this solution can support three cells with a coverage radius of 200 km each.

With the extended range technology, operators can rapidly deploy their WCDMA networks with fewer sites and lower investment.

2.2 IntroductionProviding wide coverage is a huge challenge for modern mobile communications. Distance is a main factor that affects the quality of signals. To counter signal fading, the UE must increase its power. How to control the UE power while ensuring the signal quality is a challenge for modern mobile technologies.

The area of extended range is very large, and it may have neighboring relations with many other cells. Therefore, it is necessary to select typical neighboring cells. Too many neighboring cells may lead to handover confusion, but too few neighboring cells may lead to


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high call drop rates. Neighboring cells may have the same frequency and the same base transceiver station identity code (BSIC).

Site survey is also a key factor in network planning for extended range. Extended range requires good radio propagation conditions between the antenna and the target coverage area. In addition, some special requirements of extended range need to be considered in selection of base station hardware.

Huawei extended range solution selects high-power amplifiers, high-power RRUs, high-gain antennas, and directional cells. Tower mounted amplifiers can also be configured to meet the requirement of extended range for uplink (UL) sensitivity and to reduce UL signal fading caused by long feeders.

In this solution, the base station uses the time division multiplexing (TDM) technology based on time slice. With this technology, only one cell can admit UEs at one moment. At the same time, the UEs in other cell cannot access the network because no time slice is available, but the power of the UEs will not increase.

Compared with common frequency planning, the frequency planning for extended range considers the distribution of base stations in the coverage area. Generally, base stations for extended range are built separately from other common base stations. The area of extended range is very huge, and thus the frequency planning for remote-coverage cells may be in conflict with that for normal cells. Therefore, the solution needs to fully consider the existing frequency plan and then select appropriate frequency resources for extended range.

In the coverage area, there may be many communication devices such as radars and broadcasting stations, which cause interference. In this case, you can configure the remote-coverage cell as a normal cell and use the UL frequency scanning function to identify the UL interference. Currently, the remote-coverage cell does not support the downlink (DL) frequency scanning function. Based on specific frequencies that cause UL interference, you can adjust the frequency plan.

2.3 Availability2.3.1 Intended Audience

This document is intended for:

System operators who need a general understanding of extended range feature. Personnel working on Huawei products or systems.

2.3.2 Impact Impact on the system

In TDM mode based on time slice, only one cell can admit UEs at one moment. Impact on other features

None.

2.3.3 Network Element InvolvedTable 2-1 lists the network elements (NEs) involved in extended range.


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Table 2-1 NEs involved in extended range

UE NodeB

RNC MSC Server

MGW SGSN GGSN HLR

– √ √ – – – – –

–: not involved √: involvedUE = User Equipment, RNC = Radio Network Controller, MSC Server = Mobile Service Switching Center Server, MGW = Media Gateway, SGSN = Serving GPRS Support Node, GGSN = Gateway GPRS Support Node, HLR = Home Location Register

2.3.4 Software VersionsTable 2-1 lists the product versions that support extended range.

Table 2-1 Product versions that support extended range

Product Version Remarks

BTS3812E/BTS3812AE V100R010 and later The EBBI needs to be configured.

DBS3800 V100R010 and later The EBBC needs to be configured.

DBS3900 V200R010 and later The WBBPb needs to be configured.

BTS3900/BTS3900A V200R010 and later The WBBPb needs to be configured.

2.3.5 Protocol ComplianceThis feature complies with 3GPP TS 25.211 and 3GPP TS 25.433.


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3 Technical Description

Chip 6102 provides only one set of resources for common channel search. In non-extended range mode, the traffic is relatively light, and therefore one set of resources can search three cells at the same time. In extended range mode, however, the three cells each have a coverage radius of 200 km and the traffic is relatively heavy. Therefore, the base station uses the TDM technology. In TDM mode based on time slice, only one cell can admit UEs at one moment. At the same time, the UEs in other cell cannot access the network because no time slice is available, but the power of the UEs will not increase.

The minimum unit used in resource pool search in TDM mode is time slice. The basic operations of preamble acquisition, message, and DPCCH multipath search are coherent. Therefore, the related resources can form a resource pool for TDM processing.

3.1 RACH SubchannelRACH subchannel is a subset of the set of all UL access slots. In total, there are 12 subchannels. Subchannel i (i = 0, …, 11) is composed of the following UL access slots:

UL access slot i corresponding to DL access slot i. Here, DL access slot i is within the P-CCPCH frame (10 ms) with SFN mod 8 = 0 or SFN mod 8 = 1.

UL access slot that is 12 access slots after UL access slot i.

Table 3-1 lists the UL access slots included in different RACH subchannels.

Table 3-1 UL access slots included in different RACH subchannels

Frame Specified by SFN Mod 8

Subchannel Number

0 1 2 3 4 5 6 7 8 9 10 11

0 0 1 2 3 4 5 6 7 - - - -

1 12 13 14 - - - - - 8 9 10 11

2 - - - 0 1 2 3 4 5 6 7 -

3 9 10 11 12 13 14 - - - - - 8

4 6 7 - - - - 0 1 2 3 4 5


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Frame Specified by SFN Mod 8

Subchannel Number

0 1 2 3 4 5 6 7 8 9 10 11

5 - - 8 9 10 11 12 13 14 - - -

6 3 4 5 6 7 - - - - 0 1 2

7 - - - - - 8 9 10 11 12 13 14

3.2 Subchannel-Based ManagementTime slice resources are limited. To implement extended range, TDM is applied. In TDM mode, only one cell can admit UEs at one moment. At the same time, the UEs in other cell cannot access the network because no time slice is available, but the power of the UEs will not increase. To avoid power increase in such a case, the RNC configures subchannels for each cell.

Considering the usage of access slots, the subchannel configuration scheme, as shown in Figure 3-1, is adopted for extended range.

Figure 3-1 Subchannel configuration scheme

Each cell is assigned 1,280 time slices, approximately 5,120 chips, for search. As shown in Figure 3-1, each cell uses three access slots for search and one for parameter setting.

3.3 Time Slice Allocation PolicyTime slice resources are limited. To implement extended range, TDM is applied. That is, time slices are assigned to different cells in turn.

One time slice can be assigned to only one cell at a time. When the coverage radius of a cell is 200 km, the two slots of a time slice are completely occupied by the cell. The original algorithm with the management period of two slots cannot support large-scale search. To meet


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the requirement of acquisition of three such cells, the typical time slice allocation policy, as shown in Figure 3-1, is used. This policy is based on the subchannel configuration scheme shown in 3.2.1 I. Step 1Figure 3-1.

Figure 3-1 Time slice allocation policy

As shown in Figure 3-1, the parameter setting for time slice allocation has a high requirement for time accuracy. If the time is set incorrectly, TDM in three cells cannot succeed.


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4 Implementing Extended Range

The following describes how to enable and disable extended range.

4.1 Enabling Extended Range4.1.1 Hardware Requirements

The hardware requirements of the base station for extended range are as follows:

EULP/EBBI/EBOI for BTS3812E/BTS3812AE EBBC for DBS3800 WBBPb for DBS3900 WBBPb for BTS3900/BTS3900A

4.1.2 Configuring Extended RangeDuring the initial data configuration, run the ADD LOCELL and MOD LOCELL commands, where the remote cell mode switch (RMTCM) is set to TRUE and the remote cell group index (RMTCGRPID) is set to the number of the remote cell group.

For example:

ADD LOCELL: SECT=REMOTE_SECTOR, RMTCM=TRUE, RMTCGRPID=0

4.1.3 Verifying the EnablingRun the LST LOCELL command to check whether the local cell is configured with the extended range feature.


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4.2 Disabling Extended Range4.2.1 Disabling Extended Range

During the running of the base station, run the MOD LOCELL command, where the RMTCM parameter is set to FALSE.

4.2.2 Verifying the Disabling Run the LST LOCELL command to check whether the extended range feature of the cell is disabled.


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5 Extended Range Parameters

5.1 DescriptionTable 5-1 Extended range parameter description

Parameter ID Description

RMTCM Remote Mode of the Local Cell

RMTCGRPID Remote Cell Group Index of Local Cell

5.2 Values and RangesTable 5-1 Extended range parameter values and parameter ranges

Parameter ID

Default Value

GUI Value Range

Actual Value Range

Unit MML Command

NE

RMTCM FALSE FALSE (Not Support), TRUE (Support)

FALSE, TRUE None ADD LOCELL(Optional)

NodeB

RMTCGRPID - 0~4294967295 0~4294967295 None ADD LOCELL(Optional)

NodeB

The Default Value column is valid for only the optional parameters.The "-" symbol indicates no default value.


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6 Maintenance Information

6.1 CountersNone.

6.2 AlarmsTable 6-1 Extended range alarms

Alarm ID Alarm Name Alarm Type

ALM-4033 Local Cell Unusable Fault alarm


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7 Reference Documents

The following lists the reference documents related to the feature:

1. 3GPP TS 25.211 "Physical channels and mapping of transport channels onto physical channels (FDD)"

2. 3GPP TS 25.433 "UTRAN Iub interface Node B Application Part (NBAP) signalling"3. Basic Feature Description of Huawei UMTS RAN11.0 V1.54. Optional Feature Description of Huawei UMTS RAN11.0 V1.5


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