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HOW TO CONFIGURE SMART RANGE WITH RBS2106/2206

© Ericsson AB 2005

The contents of this product are subject to revision without notice due to continued progress in methodology, design and manufacturing.

Ericsson shall have no liability for any error or damages of any kind resulting from the use of this document.

GUIDELINE

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REVISION HISTORY Rev Date Description

A 2005-01-31 Creation of document.

B 2005-03-04 Supreme Coverage added.

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Contents

1 Introduction ................................................................................4 1.1 Scope of the document ................................................4 1.2 Description of Smart Range .........................................4

2 Configuration implementation and considerations ................5 2.1 Initial configuration .......................................................5 2.2 Optimizing traffic in the subcells...................................5 2.3 GPRS/EDGE considerations........................................6 2.4 BCCH Redundancy......................................................6 2.5 Increasing cell capacity ................................................7

3 References ..................................................................................9 Appendix A – Configuring Smart Range with un-combinded mode

.................................................................................................10 Appendix B – Configuring Smart Range with TCC mode and Supreme

Coverage mode ......................................................................11

GUIDELINE

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1 Introduction

1.1 Scope of the document This guideline aims to give the reader knowledge on how to set radio network parameter to configure Smart Range using RBS 2106/2206.

The concept is supported for both RBS 2102/2202 and RBS 2106/2206, but in this document only RBS 2106/2206 is discussed.

This guideline will not describe the cabling inside the RBS 2106/2206 cabinet.

1.2 Description of Smart Range Smart Range is a solution that allows different output powers in a cell. Smart Range will facilitate increased capacity without decreasing coverage.

Smart Range utilizes the dynamic overlaid/underlaid subcell feature to implement a high power underlaid subcell, which will be used for BCCH and coverage and a low power overlaid subcell for traffic closer to the cell site.

There are three ways of implementing Smart Range in RBS2106/2206 with CDU-G.

Common for all three possible implementations are that capacity is handled by TRXs in combined mode, which are designated to overlaid subcell.

The high power underlaid subcell for coverage can by implemented by TRXs in

• Un-combined mode

• TCC mode

• Supreme Coverage mode (TCC mode combined with 4-way diversity on the uplink)

TCC and Supreme Coverage mode will have around 3 dB higher output compared to un-combined mode. The increased output power will need a doubling of the number of TRXs compared to un-combined mode for the same capacity in the underlaid subcell.

The Dynamic overlaid/underlaid subcell feature is also used to optimize the traffic distribution between the subcells.

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2 Configuration implementation and considerations

2.1 Initial configuration In Appendix A it is described how a cell without subcell structure is reconfigured to Smart Range configuration using TRXs in combined and one TRX in uncombined mode.

In Appendix B it is described how a cell without subcell structure is reconfigured to Smart Range configuration using TRXs in combined and one TRX in TCC mode or Supreme Coverage mode.

Also, the Operational Instruction, ref. [3], contains good information how this is done.

2.2 Optimizing traffic in the subcells It is important that there are always idle resources in the underlaid subcell so that incoming handover will be possible. Therefore, traffic that can be served by the overlaid subcell should be moved from underlaid subcell to overlaid as soon as possible. If CHAP=5 or 6 is used, the mobiles will be permitted to do handover directly to the overlaid subcell. The advantage with this setting is that the mobiles do not have to be connected to underlaid subcell before they are moved to overlaid subcell. CHAP=5 and 6 also allows calls to be set up directly on the OL in the case that the underlaid subcell is congested. The difference between CHAP 5 and CHAP 6 is that CHAP 6 allows immediate assignment on TCH and CHAP 5 does not. For more information about CHAPs, see [4].

The traffic in the overlaid subcell will be limited by the settings on LOL, DTCB and TAOL. If these parameters are set too low this will mean that too much traffic will be handled by the underlaid subcell, with the risk of congestion. If the parameters on the other hand is set too high there will be a risk of bad speech quality or even dropped calls in the overlaid subcell.

If frequency hopping is used in the overlaid subcell, this will compensate for the lower output power. It is recommended to hop over at least 8 frequencies to maximize the gain of frequency hopping.

Subcell Load Distribution (SCLD) can also be used to move traffic to the overlaid subcell. With SCLD the BSC decides which mobiles to move up to the overlaid by choosing the mobile with the lowest path loss. However, the parameters LOL, DTCB and TAOL will still decide when to move a mobile down from overlaid to underlaid. Therefore these parameters also need to be optimized to limit the traffic taking area of the overlaid subcell when SCLD is used.

Counters collected by STS should be used to evaluate the traffic distribution and if congestion occurred in the underlaid subcell.

The quality on overlaid subcell close to the border between subcells can be measured by MRR. This quality can be measured by starting a recording on overlaid subcell and using filter with a signal strength criteria equal to LOL - BSPWRT (OL).

GUIDELINE

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2.3 GPRS/EDGE considerations The recommendation is to allocate PDCH in the underlaid subcell to provide continuous GPRS/EDGE coverage in the cell.

However, by following this strategy there will be fewer resources available for speech in the in underlaid subcell.

If PDCH is decided to be configured on underlaid subcell, it is important to allow preemption of on-demand PDCH so that incoming calls from surrounding cells can be given a resource in underlaid subcell. A more aggressive setting of LOL, DTCB and TAOL can also be applied to move more traffic to the overlaid subcell and to avoid preemption.

Where PDCH both fixed and on-demand channels are configured is controlled by the parameters PDCHALLOC and SCALLOC.

2.4 BCCH Redundancy

2.4.1 Smart Range with uncombined mode

For larger Smart Range configurations, where more than one TRX/TX are used in underlaid subcell, there will be an automatic BCCH Redundancy. It can be achieved by only dedicating the TRXs/TXs in combined mode to a channel group.

To achieve BCCH Redundancy in this case the TRX in combined mode should be dedicated to the channel group used in overlaid subcell. The TRXs/TXs in un-combined mode should not be designated to any channel group. Since the underlaid subcell is allocated resources first, there should be no risk that an un-combined TRX/TX is used in the overlaid subcell.

If only one TRX/TX is configured in channel group 0, carrying the BCCH, there will be no automatic BCCH Redundancy. This is because TRXs/TXs have to be connected to specific channel groups to be able to configure Smart Range with un-combined mode.

This means that if the only TRX/TX locked to channel group 0 fails the BSC cannot reconfigure any of the TRXs/TXs used in another channel group to be used as BCCH in channel group 0.

In case of failure of the only TRX/ TX in channel group 0, the TRX/ TX must manually be unlocked from another channel group to be able to be reconfigured as BCCH until the failed TRX/ TX has been replaced or repaired.

2.4.2 Smart Range with TCC or Supreme Coverage mode

For larger configurations with more than two TRXs/TXs, more than one whole dTRU, that are using TCC in the underlaid subcell, there will be an automatic BCCH Redundancy.

If there are only two TRXs/TXs, one whole dTRU, that are using TCC in the underlaid subcell, there will be no automatic BCCH Redundancy. In this case, there are two ways to manually reconfigure BCCH. First option is that the ordered power on the BCCH transmitter can be decreased to an output power that can be handled by the TRX/TX,

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that is set BSPWRB to 47 dBm for 800/900 cell. Second option is to configure two of the combined TRX/TX to be able to use TCC, this is done by blocking and taking one TRX/TX out of service.

The first options leads to that the cell coverage decreases by 6dB and the second options leads to that capacity corresponding to one TRX is lost.

The choice of option will be determined by if coverage or capacity should be prioritized.

2.5 Increasing cell capacity As the traffic increases in the network more resources must be added. The capacity in Smart Range cells can, as in normal cells, be increased by adding TRXs. More than one cabinet can be used in Smart Range configurations together with the feature RBS2000 synchronization.

Below are a number of possible configurations shown as an example of how the capacity in a three-sector site can be increased. In the figures a dTRU with two cables connected symbolizes TRXs in un-combined mode whereas TRXs in combined mode have only one cable between the dTRU and the CDU-G.

The configurations, except 3/3/3, are also valid for Supreme Coverage in which a un-combined TRX is substituted by two TRXs using TCC.

Note that the 2/2/2 and 4/4/4 configurations are not Smart Range configurations and all TRXs in these configurations are in un-combined mode.

2/2/2

5 dTRU

CDU-G

Tx-cabling

3/3/3

5 dTRU

CDU-G

Tx-cabling

3/3/3

3 dTRU

CDU - G Tx - cabling

3 dTRU

CDU - G Tx - cabling

Cell A B C Cell A B C

6 dTRU

CDU - G Tx - cabling

4/4/4 6/6/6

9 dTRU

CDU-G

Tx-cabling

Cell A B C A B C Cell A B C A B C

= Cell A

= Cell B

= Cell C

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12 dTRU

CDU - G Tx - cabling

12 dTRU

CDU - G Tx - cabling

8/8/8Cell A A A B B B C C C

15 dTRU

CDU - G Tx - cabling

10/10/10Cell A A A B B B C C C

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3 References [1] User Description, Overlaid/Underlaid Subcells 66/1553-HSC 103 12/4

[2] User Description, Locating 65/1553-HSC 103 12/4

[3] BSC, Subcell Structure, Define OPI 3/154 31-ANT 240 09

[4] User Description, Channel Administration 54/1553-HSC 103 12/4

GUIDELINE

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Appendix A Configuring Smart Range with un-combined mode The procedure below assumes that two channel groups are used and any re-cabling needed in the BTS cabinet is performed.

1. Configure OL/UL subcell structure (RLDSI) 2. Copy UL parameter settings to OL.

BSPWRT and MSTXPWR (RLCPC: SCTYPE =OL…;) MS Power control (RLPCC: SCTYPE =OL,…..; ) BTS Power control (RLBCC: SCTYPE =OL,…..;) AMR Power control (RLAPC: SCTYPE =OL,…..;) Intra cell Handover (RLIHC: SCTYPE =OL,…..;) Urgency condition for Bad Quality HO (RLLUC: SCTYPE=OL,…..;)

3. Compensate Locating for lower output power in overlaid subcell BSTXPWR [OL] = BSTXPWR [UL] –3 (RLLOC: SCTYPE =OL,…..;)

4. Define cell locating overlaid subcell data. LOL, LOLHYST, TAOL, TAOLHYST (RLOLC: SCTYPE =OL,…..;)

5. If Subcell Load Distribution is used, set values. SCLD, SCLDLL, SCLDUL (RLLLC)

6. Connect TRX and TX to channel group. Connect TRX and TX in un-combined mode to CHGR 0 (RXMOC) Connect TRX and TX in combined mode to CHGR 1 (RXMOC) The TRX and TX have to be taken out of service to perform RXMOC.

7. Change CHAP setting to either 5, 6 (RLHPC) CHAP=5 does not allow immediate assignment on TCH CHAP=6 allows immediate assignment on TCH

8. Change SDCCH configuration Move all SDCCH/8 to CHGR 0 (RLCCC)

9. Move CHGR 1 to overlaid subcell (RLDGC) 10. Adjust supervision of logical channels to subcell structure (RLSLC, RLSLI) 11. Activate overlaid subcell (RLSTC: SCTYPE=OL, STATE=ACTIVE,…..)

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Appendix B Configuring Smart Range with TCC mode and Supreme Coverage mode The procedure below assumes that two channel groups are used and any re-cabling needed in the BTS cabinet is performed.

1. Configure OL/UL subcell structure (RLDSI) 2. Copy UL parameter settings to OL.

BSPWRT and MSTXPWR (RLCPC: SCTYPE =OL…;) MS Power control (RLPCC: SCTYPE =OL,…..; ) BTS Power control (RLBCC: SCTYPE =OL,…..;) AMR Power control (RLAPC: SCTYPE =OL,…..;) Intra cell Handover (RLIHC: SCTYPE =OL,…..;) Urgency condition for Bad Quality HO (RLLUC: SCTYPE=OL,…..;)

3. Compensate Locating for lower output power in overlaid subcell BSTXPWR [OL] = BSTXPWR [UL] –6 (RLLOC: SCTYPE =OL,…..;)

4. Define cell locating overlaid subcell data. LOL, LOLHYST, TAOL, TAOLHYST (RLOLC: SCTYPE =OL,…..;)

5. If Subcell Load Distribution is used, set values. SCLD, SCLDLL, SCLDUL (RLLLC)

6. Change CHAP setting to either 5, 6 (RLHPC) CHAP=5 does not allow immediate assignment on TCH CHAP=6 allows immediate assignment on TCH

7. Change SDCCH configuration Move all SDCCH/8 to CHGR 0 (RLCCC)

8. Block and take out of service TRXs, TX to use TCC (RXBLI, RXESE) 9. Adjust maximum power in TXs

For GSM800/900: RXMOC: MO=RXOTX-x-x-x, MPWR=51….) For GSM1800/1900: RXMOC: MO=RXOTX-x-x-x, MPWR=49….)

10. Deblock and take into service one of TRXs in dTRU to use TCC (RXESI, RXBLE)

11. If 4-way Diversity should be used Block and take out of service all TRXs in combined mode. (RXBLI, RXESE) Connect the TRXs to the CHGR to be used in OL subcell. (RXMOC) Deblock and take into service all TRXs in combined mode. (RXESI, RXBLE) Block and take out of service TRXs, RX to use TCC (RXBLI, RXESE) Activate 4-way Diversity on RX (RXMOC:MO=RXORX-x-x-x, RXD=ABCD;) Deblock and take into service one TRXs in each dTRU to use TCC (RXESI, RXBLE)

12. Activate TCC on BCCH TRX

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For GSM800/900: RLCPC: SCTYPE=UL, BSPWRB=51….) For GSM1800/1900: RLCPC: SCTYPE=UL, BSPWRB=49….)

13. Move CHGR 1 to overlaid subcell (RLDGC) 14. Adjust supervision of logical channels to subcell structure (RLSLC, RLSLI) 15. Activate overlaid subcell (RLSTC: SCTYPE=OL, STATE=ACTIVE,…..)