Frequency Planning
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Frequency Planning Frequency Planning By Muhammad Rehan Ashraf LCC South
Transcript of Frequency Planning
Frequency PlanningFrequency Planning
By
Muhammad Rehan AshrafLCC South
Overview
• Traditional Frequency PlanningMultiple Reuse Planning
Fractional Load Planning
• GSM SpectrumGSM 900 Spectrum
GSM 1800 Spectrum
• TP South Frequency PlanGSM 900 Strategy
GSM 1800 Strategy
• Automatic Frequency Planning
• Manual Vs. Automatic Frequency Planning
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Traditional Frequency Planning
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Multiple Reuse Planning
• MRP (Multiple Reuse Planning) technology divide the whole frequency resources into different subgroups according to specific principles.
• The most common frequency re‐used patterns are the 7/21, 4/12 and sometimes also the 3/9.
• The definition of a 7/21 re‐use pattern is that all available frequencies are divided into 21 frequency groups and that all ofthese groups are used in 21 cells (7/21) before they are repeated. These cells are then used in 7 sites (7/21). This is true if “three sector sites” are used (7 sites with 3 cells each ⇒ 21 cells).
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Multiple Reuse Planning
• Divide the spectrum into groups.
• For example N=7, divide the spectrum into 21 groups.
• Assign them manually to the 21 sectors of the cluster.
• Rules:– Avoid co‐channel neighbors.
– Avoid adjacent neighbors.
– Avoid 2nd co‐channel neighbors.
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Fractional Load Planning
• The principles of fractional re‐use are to change the TCH frequency plan. Instead of respecting a conventional pattern, TRXs are hopping on frequency groups.
• The most common FLP patterns are 1/1 and 1/3.
– in 1/1 all cells in an area use the same TCH frequencies.
– in 1/3 where every third cell use the same TCH frequencies.
• FLP requires Synthesizer hopping with parameters HSN, MAIO to avoid the co‐channel and adjacent channel interference.
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Fractional Load Planning
1/1 Reuse pattern• All the TCH frequencies are
gathered in one unique group T, that is allocated to every cell as shown in figure.
• The reuse distance here only refers to the distance between two cells using co‐channel frequencies. But, in 1/1, HSN and MAIO allocation strategies allow to avoid co‐channel collision in a site.
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Fractional Load Planning
1/3 Reuse pattern• The TCH available
bandwidth is divided in three groups T1, T2 and T3 and allocated as shown in figure.
• The co‐sector separation, between TCH TRX within one sector, is 600 KHz.
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Fractional Load Planning
Fractional Load• It represents the time fraction for a given frequency being used in the
network.
• fractional load is simply the ratio between the number of hopping TRXs in a cell and the number of hopping frequencies.
Fractional Load per cell = Number of Hopping TRXs * 100 %
Number of Hopping Frequencies
Reuse Pattern Max Fractional Load
1/1 16%
1/3 50%
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GSM Spectrum
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GSM 900 Spectrum
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GSM 900 Spectrum
• Width of Duplex sub‐band is 25 MHz and Duplex spacing is 45 MHz. Frequency spacing between carriers is 200 KHz (0.2MHz)
• Total number of carriers = [ Duplex band (Uplink or Downlink) – Frequency Spacing] / Frequency Spacing]
= [ 25 – 0.2 (Guard band) / 0.2 ]
= [ 24.8 / 0.2]
Total number of carriers = 124
Uplink and Downlink ARFCN’s for GSM 900Uplink and Downlink ARFCN’s can be calculated from the following formula:
• Uplink Frequencies: Fu(n) = 890 + 0.2 n where (1<=n<=124)
• Downlink Frequencies: Fd(n) = Fu(n) + 45Where n is ARFCN (Absolute Radio Frequency Carrier Number)
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TP GSM 900 Spectrum
No. ARFCN Uplink Downlink
1 63 902.6 947.6
2 64 902.8 947.8
3 65 903 948
4 66 903.2 948.2
5 67 903.4 948.4
6 68 903.6 948.6
7 69 903.8 948.8
8 70 904 949
9 71 904.2 949.2
10 72 904.4 949.4
11 73 904.6 949.6
12 74 904.8 949.8
No. ARFCN Uplink Downlink
13 75 905 950
14 76 905.2 950.2
15 77 905.4 950.4
16 78 905.6 950.6
17 79 905.8 950.8
18 80 906 951
19 81 906.2 951.2
20 82 906.4 951.4
21 83 906.6 951.6
22 84 906.8 951.8
23 85 907 952
24 86 907.2 952.213
GSM 1800 Spectrum
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GSM 1800 Spectrum
• Width of duplex sub‐band is 75 MHz and Duplex spacing is 95 MHz. Frequency spacing is 200 KHz and with one guard band we get:
Total number of carriers = (75 – 0.2) / 0.2
Total number of carriers = 374
Uplink and Downlink ARFCN’s for DCS 1800
Uplink and Downlink ARFCN’s can be calculated from the following formula:
• Uplink Frequencies: Fu(n) = 1710.2 + 0.2 (n – 512) where (512 <=n<= 885)
• Downlink Frequencies: Fd(n) = Fu(n) + 95
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TP GSM 1800 Spectrum
No. ARFCN Uplink Downlink
1 586 1725 1820
2 587 1725.2 1820.2
3 588 1725.4 1820.4
4 589 1725.6 1820.6
5 590 1725.8 1820.8
6 591 1726 1821
7 592 1726.2 1821.2
8 593 1726.4 1821.4
9 594 1726.6 1821.6
10 595 1726.8 1821.8
11 596 1727 1822
12 597 1727.2 1822.2
13 598 1727.4 1822.4
14 599 1727.6 1822.6
15 600 1727.8 1822.8
No. ARFCN Uplink Downlink
16 601 1728 1823
17 602 1728.2 1823.2
18 603 1728.4 1823.4
19 604 1728.6 1823.6
20 605 1728.8 1823.8
21 606 1729 1824
22 607 1729.2 1824.2
23 608 1729.4 1824.4
24 609 1729.6 1824.6
25 610 1729.8 1824.8
26 611 1730 1825
27 612 1730.2 1825.2
28 613 1730.4 1825.4
29 614 1730.6 1825.6
30 615 1730.8 1825.8
No. ARFCN Uplink Downlink
31 616 1731 1826
32 617 1731.2 1826.2
33 618 1731.4 1826.4
34 619 1731.6 1826.6
35 620 1731.8 1826.8
36 621 1732 1827
37 622 1732.2 1827.2
38 623 1732.4 1827.4
39 624 1732.6 1827.6
40 625 1732.8 1827.8
41 626 1733 1828
42 627 1733.2 1828.2
43 628 1733.4 1828.4
44 629 1733.6 1828.6
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TP South Frequency Plan
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GSM 900 Strategy
Urban/Sub Urban
• BCCH frequencies are chosen best available basis.
• FLP 1/1 is used for TCH
• MAIO 1,3 and 5 can be used.
• Ideally 3 and maximum 4 hopping TRXs allowed.
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GSM 900 Strategy
Rural/Rural Road/ Extremely Remote
• BCCH frequencies are chosen best available basis.
• FLP 1/1 is used for TCH
• MAIO 0,2,4,6,8 and 10 can be used.
• Maximum 6 hopping TRXs allowed.
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GSM 1800 Strategy
• BCCH frequencies are chosen best available basis.
• FLP 1/3 is used for TCH
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GSM 1800 Strategy
MA List
MAIO Management
• Maximum 5,4,5 hopping TRXs allowed on sectors 1,2 and 3 respectively.
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Automatic Frequency Planning
• AFP dramatically shortens the amount of time an engineer spends on frequency planning by automatically generating plans through an algorithmic process.
• AFP can generate an initial plan for a brand new network or reconfigure an RF plan for an existing network.
• ILSA is an example of AFP tool by Aircom.
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Manual Vs Automatic Frequency Planning
Manual
• Easy maintenance.
• Inefficient use of spectrum.
• Doesn't take advantage of terrain characteristics.
• Unable to cope with capacity needs.
• Implementation and maintenance is costly.
• Efficient usage of spectrum.
• Use terrain characteristics.
• Resolve capacity needs.
Automatic
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