MBCMB C-Si Sin n le BCCH
Tr ần Việt Dũng-P.KTKT
- May 2011 -
Contents
Introduction
Trial project Discussion
2
Contents
Introduction
Trial project Discussion
2
Introduction
Some solutions solut ions for reduci ng TCH TCH con congestion gestion What is tra tr adit dition iona al dua du al site? si te? Wha hatt is MBC MBC--Sin le BC BCC CH? Why MBC-Single BCCH? Summary Summ ary of o f Adv Ad v./ ./Disadv. Disadv. of MBC MBC..
3
Introduction TCH congestion: Some solutions •
Hard solutions: More HW – Add TRXs. – Add BTSs.
•
Soft solution s: No more HW. – RNO. • Coverage. • Channel. • Service.
– Activate features supported by BSS. • Dynamic Half Rate Allocation. • Dynamic FR/HR Mode Adaptation . •
.
• Cell Load Sharing. • Multi -Band Cell (Singl e-BCCH).
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Introduction
Introduction of MBC – Multi Band Cell
5
Introduction
Tranditional Dualband Site: Dual BCCH. Multi-band Operation (D-BCCH) allows configuring two different frequency bands in the same or different site location using dual BCCH. It allows reselection, assignment and handovers between different bands. Cell DCS 1800 carries BCCH, SDCCH, PDCH & TCH
Cell GSM 900 carr ies BCCH, SDCCH, PDCH & TCH.
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Introduction What is Single-BCCH? z
Sin le-BCCH: Common BCCH Cell, also called GSM900&DCS1800, Multi-band cell;
z
Two layers in a cell: UL (900M) and OL (1800M);
z
The UL covers the whole cell area, The OL may not match the UL coverage area;
z
UL mana es BCCH, SDCCH,PDCH and TCH channels, while OL onl manages the TCH channels. OL(DCS 1800) cont ains only TCH, For Traffic Load
UL(GSM 900) carries BCCH, SDCCH, PDCH & TCH, For Coverage 7
Introduction
Multi Band Cell Configurations
8
Conf.
Subcell 1
Subcell 2
1
GSM800
GSM900
3
GSM800
GSM1900
4
GSM900
GSM1800
6
GSM800 AND GSM900
GSM800
7
GSM800 AND GSM900
GSM900
9
GSM800 AND GSM900
GSM1800
10
GSM800 AND GSM900
GSM1900
Introduction Why Single-BCCH? 1. Im prov e r adi o perf or manc e: There are several restrictions on the usage of features Dynamic BTS Power Control, Discontinuous Transmission and Frequency Hopping on the BCCH frequency. By omitting the BCCH from one of the fre uenc bands in a multi band cell, these restrictions are removed for that band. .
9
Introduction
Why Single-BCCH (cont.)? 2. Improve capability: UL and OL share the BCCH, SDCCH, PDCH, and the TCH channels will be increased accordingly.
OL(DCS 1800) cont ains only TCH, For Traffic Load
UL(GSM 900) carries BCCH, SDCCH, PDCH & TCH, For Coverage
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Introduction
Example of theoretical capacity gain… Traditional Dual-Band Cell
900 TCHs
SDCCH Required
Erlang B (2% GOS)
1800 TCHs
SDCCH Required
Erlang B (2% GOS)
900 + 1800 Erl ang B (2% GOS)
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1
2.3
29
2
21.0
23.3
14
1
8.2
29
2
21.0
29.2
21
2
14.0
29
2
21.0
35.0
29
2
21.0
29
2
21.0
42.0
Multi Band Cell 900 TCHs
1800 TCHs
Multi-Band o a
SDCCH equ re
Erlan B 2% GOS
4
32
36
3
27.3
12
32
44
3
34.7
19
32
51
4
41.2
27
32
59
4
48.7
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Introduction
Why Single-BCCH (cont.)? 3. Simplify network structure:
12
z
Reduce number of cells in the network
z
Reduce number of Location Area Codes
z
Reduce number of neighboring cells
z
Simplify multi-layer network into one layer network.
Æ
BSC capacity
Introduction
Multiband Operation – Dual BCCH cells
A D F C
13
E
B
A-B A-C A-D A-F B-C B-D B-F ... ... C-E C-F D-E E-F
A-B A-C B-A C-A C-B
Multiband Cell Common BCCH cells
A
C
B
Adv./Disadv. of Dual-BCCH and Single-BCCH
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Introduction
Adv./Disadv. of Dual-BCCH .
• Dual Band mobiles can camp on either band. • 1800 MHz can provide additional capacity in high density areas. • 1800 MHz single band mobiles can still be served on the 1800MHz layer. • The network optimization becomes easier. ¾Disadv.:
• Extra cells have to be defined. A dual band sector needs definition of 2 cells: one cell for each band. • Significant increase in neighbor relations since handovers will be permitted between cells with the same band and between the different bands. This could ecome a pro em e ne g or re a ons m s reac e an cou a ec the accuracy of measurement reports sent by the MS. • Spectrum to be allocated for BCCH in the two bands. Can be a problem in s ectrum-limited markets.
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Introduction
v.
sa v. o
-
¾ Adv.:
• Improve capacity. • Improve radio performance by DTX, BTSPC and FH, • The number of defined cells and neighbor relations in a BSC is reduced. Reduction in the number of neighbor relations contributes to . • Signaling load on the system eased: No reselection of 900M/1800M cells, less inter-cell HO. • Easy O&M. ¾Disadv.:
• Non-BCCH band single-band mobiles will have no coverage. • The network o timization becomes more difficult. 16
Contents
Introduction
Trial Project Discussion
17
Preparations
Transceiver Group Synchronization Dynamic Overlaid/Underlaid Subcells Multiband Cell DT Planning Considerations
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Preparations
Transceiver Group Synchronization
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Preparations Transceiver Group Synchronization In order to be able to configure a Multi Band Cell, , either being located in the same RBS cabinet and/or by using the feature Transceiver Group Synchronizations if the transceivers are located in different RBS cabinets.
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Preparations
ESB cable between two RBS 2216 (length 1.6m) – Product Number RPM 119 0158/01600
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Preparations
TT
ESB Cable Type
Description
Product Number
1
DB9 ‐ RJ45
RBS2206 ‐ RBS2216
RPM 119 0476/15000
2
DB9 ‐ DB9
3
DB9 Terminator
RBS2206 ‐ RBS2206 RPM 513 1104/15000 Terminator at ESB port of RBS2206 RPT 403 805/01 Terminator at ESB port of
5
ESB cable 2206
ESB Cable connect from DXU to ESB port
RPM 513 904/1+
For more details, refer this document
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TG synchronization-User Guide
Preparations
DCS1800 Overlay
GSM900 Underlay
23
Preparations
Dynamic Overlaid/Underlaid Subcells In multi band networks it can often be assumed that one frequency band has generally "better" coverage than the other. When combining two such frequency bands into one cell it is naturally suitable to re-use the subcell structure concept from the feature Dynamic Overlaid/Underlaid Subcells. The feature Dynamic Overlaid/Underlaid Subcells is a prerequisite for the u t an e . e requency an w t etter coverage can be configured in the UL subcell and the other frequency band with "worse" coverage in the OL subcell. The parameter group in a subcell. The parameter CSYSTYPE has a different meaning in multi band cells, as it defines the BCCH frequency . 24
Preparations
Dynamic Overlaid/Underlaid Subcells (cont.) The pathloss, TA and DTCB (Distance-To-Cell-Border) frequency band used in the OL subcell in order to secure continuous service within the cell
25
Preparations
Dynamic Overlaid/Underlaid Subcells (cont.) The traffic load distribution between the two different frequency bands is handled by the Subcell Load Distribution function, allowing the frequency band in the preferred subcell (UL or OL as selected by the parameter to e e rst, an a ter a certa n amount o traffic has been reached, the frequency band in the other subcell.
26
Preparations
Dynamic Overlaid/Underlaid Subcells (cont.) It is also possible to configure the BCCH in the Overlaid " " coverage, but this is not advisable as this frequency band may experience greater attenuation leading to MS’s not bein able to re-select the network es eciall inside buildings, or in basements, etc.)
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Preparations
Multiband Cell DT
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Multiband Cell DT.doc
Preparations
Planning Considerations
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Preparations
• Synchronization If 900 and 1800 cabinets are combined, their synchronization mus e ep : rror o ync …
• SDCCH Capacity Limitations Due to the fact that SDCCHs should not be configured in the GSM-1800 Overlaid Subcells, it is possible that the default limitation of 1 SDCCH/8 per TRX in each channel group will prove to be a problem. Æ Activate feature Increase SDCCH/8.
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Preparations
• Selection of the BCCH frequency band , should be considered: Coverage and frequency planning. • The preferred subcell: UL or OL
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Preparations
• Azimuth of the antenna. , the coverage direction of 900M and 1800M should be identical whenever possible. Æ The swa ed antenna is bi roblem.
• Backup Power.
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Contents
Basic Principles
Trial Project Discussion
33
Trial Project Preparations completed
P.KT: PA trien khai va CDD Dai VT: HW, cable, bus
BTS configuration
Đài ĐHKT: Khai báo CDD Trial Project
Data configuration
Parameter Tuning
DT and Traffic analysis
Trial completed and Report
P.KT: DT, Tối ưu tham số Report
Contents
Basic Principles
Trial and Implementation Discussion
