PCH – AGCH - LAC
BSC Paging capacity
The maximum delivery rate of 1 paging/15ms = 240.000 pagings per hour which is applied in releases starting from BR70/30 (the slightly slower delivery rate was applied in order to avoid unnecessary buffer congestion situations in the BTS). It is recommended to plan LAC-splitting or BSC re-homing if the PCH-Load reaches 80% and before PCH-Load reaches 90%, perform LAC-splitting or BSC re-homing. 80% load = 192.000 pagings per hour/LAC 90% load = 216.000 pagings per hour/LAC The maximum number of configurable LAC is restricted to 20, the number of paging blocks possible are 9 (cells with number of paging blocks greater than 8 are handled all together in the fastest delivery rate)
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BTS Paging capacity BTS Paging capacity CCCH Utilization NBLKACGR=1 3 Subscriber pages/CCCH Ù TMSI Reallocation =ON Paging Repetition Factor = 1.3 Combined BCCH: 33% CCCH-Utiliz.: 33% x 2 x 3 x 4.25 x
3600 / 1.3 = 23,303
66% CCCH-Utiliz.: 66% x 2 x 3 x 4.25 x 3600 / 1.3 = 46,606
Uncombined BCCH: 33% CCCH-Utiliz.: 33% x 8 x 3 x 4.25 x
3600 / 1.3 = 93,212
66% CCCH-Utiliz.: 66% x 8 x 3 x 4.25 x 3600 / 1.3 = 186,424
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AGCH Capacity • The logical Channels PCH and AGCH share the same CCCH-Blocks whereas the PCH takes precedence over the AGCH when a PCHCommand is waiting in the queue. • Reserved AGCH using parameter NBLKACGR = 1 (value: 0..7) • Up to BR7 the number of AGCH events that can be served per AGCH message = 1 (one) immediate assignment (IMASS)
NBLKACGR = 1: AGCH Capacity = 4.25 IMASS/sec or 15,300 IMASS/hr With refer to this, whenever the threshold of NBLKACGR = 1 is exceeded additional reserved AGCH is required accordingly
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Simulation CCCH Parameter CCCH Blocks
Blocks 9
51 Multi-frames/s Pages/CCCH Paging Rep
CCCH-AGCH CCCH-PCH
1 8
4.25 4.25
1 3
CCCH-AGCH CCCH-PCH
2 7
4.25 4.25
CCCH-AGCH CCCH-PCH
3 6
CCCH-AGCH CCCH-PCH
Ref. Max. Pages/h
CCCH-PCH Utilization
1.3
15,300 180,000
64%
1 3
1.3
30,600 180,000
73%
4.25 4.25
1 3
1.3
45,900 180,000
85%
4 5
4.25 4.25
1 3
1.3
61,200 176,538
100%
CCCH-AGCH CCCH-PCH
5 4
4.25 4.25
1 3
1.3
76,500 141,231
100%
CCCH-AGCH CCCH-PCH
6 3
4.25 4.25
1 3
1.3
91,800 105,923
100%
CCCH-AGCH CCCH-PCH
7 2
4.25 4.25
1 3
1.3
107,100 70,615
100%
CCCH-AGCH CCCH-PCH
8 1
4.25 4.25
1 3
1.3
122,400 35,308
100%
Note: Maximum Allowed AGCH reserved based on the simulation is proposed NBLKACGR = 3 in order to have safety margin of CCCH utilization for shared PCH & AGCH Page 5
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Counter PCH: TACCBPRO 1: Number of accesses to the PCH NTDMPCH: 1 Number of transmitted messages for CS traffic 2 Number of transmitted messages for PS traffic 3 Number of messages discarded from the paging queue (NTDMPCH) resp. packet paging queue (NTDMPPCH) for CS traffic 4 Number of messages discarded from the paging queue (NTDMPCH) resp. packet paging queue (NTDMPPCH) for PS traffic
AGCH: TACCBPRO 2: Number of accesses to the AGCH NTDMAGCH: 1 Number of transmitted messages on the AGCH CS traffic 2 Number of transmitted messages on the AGCH PS traffic 3 Number of messages discarded from the AGCH queue CS traffic 4 Number of messages discarded from the AGCH queue PS traffic Page 6
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LAC Splitting - Guideline - High Season Factor - Measurement PCH & AGCH: TACCBPRO NTDM
Calculate High Season Load Estimation: PCH & AGCH
AGCH Reserved Requirement
>3
If required with max NBLKACGR=5 as limit, with dimensioning parameter: Max Paging 120,000 pages/h per LAC
NBLKACGR
≤3 Max Paging 150,000 pages/h per LAC
Dimensioning Result: # LAC # NBLKACGR
Note: For NBLKACGR is based on 15,300 IMASS/hr per 1(one) reserved AGCH therefore the AGCH reserved requirement for High Season is defined by using NBLKACGR = [Estimated Load AGCH]/ 15,300 Page 7
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LAC Splitting 1. Guideline for AGCH is NBLKACGR=1 with 4.25 IMASS/sec or 15,300 IMASS/hr 2. Guideline for PCH with max NBLKACGR = 3 (45,900 IMASS/hr) is proposed resulting CCCH-PCH utilization 85% with refer to 180,000 pages/h. Though, for dimensioning 150,000 pages/h is proposed as max paging per LAC to have a safety margin 3. For the case where the estimation of AGCH reserved requirement >3 then LAC dimensioning will be based on 120,000 pages/h as max paging per LAC to have a safety margin (Note: NBLKACGR = 5 as the limitation) 4. HO Attempt should be used as reference to split the LAC border in the urban area
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