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# Gsm frequency-planning-issue2

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### Gsm frequency-planning-issue2

2. 2. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page2 Contents 1. Frequency Planning 2. Normal Frequency Reuse Technology 3. Tight Frequency Reuse 4. Multiple Reuse Pattern Technology 5. Concentric Cell Technology 6. Frequency Hopping
3. 3. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page3 Contents 1. Frequency Planning Basic 1.1 Frequency Resource of GSM System 1.2 Concept of Frequency Reuse 1.3 Reuse Density 1.4 C/I Ratio
4. 4. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page4 P-GSM 900 : DCS 1800 : 1710 1785 1805 1880 Duplex distance : 95 MHz 890 915 935 960 Duplex distance : 45 MHz Frequency Resource of GSM System
5. 5. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page5 Frequency Resource of GSM System Frequency Spectrum Range (MHz) Uplink Frequency Value ARFCN Downlink Frequency Value P-GSM900 890~915 935~960 Fu(n)=890+0.2n 1≦n ≦ 124 Fd(n)=Fu(n)+45 E-GSM900 880~915 925~960 Fu(n)=890+0.2n Fu(n)=890+0.2(n-1024) 0 ≦ n ≦ 124 975 ≦ n ≦ 1023 Fd(n)=Fu(n)+45 R-GSM900 876~915 921~960 Fu(n)=890+0.2n Fu(n)=890+0.2(n-1024) 0 ≦ n ≦ 124 955 ≦ n ≦ 1023 Fd(n)=Fu(n)+45 DCS1800 1710~1785 1805~1880 Fu(n)=1710.2+0.2(n-512) 512 ≦ n ≦ 885 Fd(n)=Fu(n)+95 PCS1900 1850~1910 1930~1990 Fu(n)=1850.2+0.2(n-512) 512 ≦ n ≦ 810 Fd(n)=Fu(n)+80
7. 7. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page7 Example of Frequency Reuse  Frequency resource is limited. If there is 8MHz frequency resource, 8 MHz = 40 channels × 8 timeslots = 320  Max. 320 users can access the network at the same time.  If every frequency is reused N times  Max. 320×N uses can access the network at the same time.
8. 8. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page8  The spectrum utilization ratio can be expressed by frequency reuse density (freuse), which reveals the tightness of the frequency reuse and can be expressed by the following equation  NARFCN is the total number of the available channel numbers,  NTRX is the number of TRXs configured for the cell. Reuse Density TRX ARFCN reuse N N f
9. 9. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page9 Question (1) Frequency bandwidth is 12MHZ, if frequency reuse density is 4x3,each cell has how many TRX? (2) Frequency bandwidth is 6MHZ, if frequency reuse density is 2x3,each cell has how many TRX?
10. 10. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page10 Looser reuse Higher frequency reuse efficiency, but interference is serious. More technique is needed. Tighter reuse 0 12 20 Little interference, but frequency reuse efficiency is low. Reuse Density  Reuse density is the number of cells in a basic reuse cluster.  For the n x m frequency reuse pattern,  n: The number of BTSs in the reuse clusters  m: The number of the cells under each BTS. mnfreuse
11. 11. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page11 4×3 Frequency Reuse A1 C1 B1 D1 A2 A3 B2 B3 C2 C3 D2 D3 A1 C1 B1 D1 A2 A3 B2 B3 C2 C3 D2 D3 A1 C1 B1 D1 A2 A3 B2 B3 C2 C3 D2 D3 A1 C1 B1 D1 A2 A3 B2 B3 C2 C3 D2 D3 A1 C1 B1 D1 A2 A3 B2 B3 C2 C3 D2 D3 A1 C1 B1 D1 A2 A3 B2 B3 C2 C3 D2 D3
12. 12. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page12 Requirement for C/I Ratio All useful signals Carrier All useless signals Interference= Useful signal Noise from environment Other signals C/I =
13. 13. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page13 Requirement for C/I Ratio Interference C/I C/I in Actual Project (3 dB margin is needed ) Co-channel ≥ 9dB ≥ 12dB Adjacent-channel ≥- 9dB ≥- 6dB Carrier offset reaches 400 KHz ≥- 41dB
14. 14. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page14 Exercise Cell A fre 5 Cell C fre 4 Cell D fre 3 Cell B fre 5?dB< ?dB< ?dB< -70dB
15. 15. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page15 Contents 1. Frequency Planning 2. Normal Frequency Reuse Technology 3. Tight Frequency Reuse 4. Concentric Cell Technology 5. Multiple Reuse Pattern Technology 6. Frequency Hopping
16. 16. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page16 Example of 4 x 3 Frequency Reuse Hereunder are several assumptions The available bandwidth is 10MHz. The channel number is 45~94  BCCH 81~94 (14 channel numbers in total, 81~82 are reserved)  The other channel numbers are allocated to TCH  So the maximum base station configuration is S4/4/4, and the frequency reuse density is 12.5 (50/4 = 12.5) Frequency group number A1 B1 C1 D1 A2 B2 C2 D2 A3 B3 C3 D3 Channel Number of Each Frequency Group 94 93 92 91 90 89 88 87 86 85 84 83 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45
17. 17. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page17 4 x 3 Frequency Reuse Conclusion  The 4 x 3 frequency reuse pattern is a basic technology applied in frequency planning. Which must be applied to the BCCH in frequency aggressive reuse technologies  If the network capacity needs to be further expanded, the following measures can be taken:  Split a cell into smaller cells.  Utilize new frequency resources. For example, you can establish a DSC 1800MHz network.  Under the current 900MHz network, use more tight frequency reuse technology to expand the network capacity.  At present, the tight frequency reuse technology works as the most economical and convenient way to expand the network capacity, so it is also the most popular with carriers.  The typical frequency reuse technology includes 3 x 3, 2 x 6, 2 x 3, 1 x 3, and 1 x 1.
18. 18. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page18 Contents 1. Frequency Planning 2. Normal Frequency Reuse Technology 3. Tight Frequency Reuse 4. Concentric Cell Technology 5. Multiple Reuse Pattern Technology 6. Frequency Hopping
19. 19. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page19 1 x 3 Frequency Reuse Pattern  1 x 3 frequency reuse pattern is also called fractional reuse.  For 1 x 3 or 1 x 1 frequency reuse pattern, the reuse distance is quite small, so the interference in the network is quite great. Therefore, to avoid frequency collision, you must use RF hopping technology and set the parameters, including MA (mobile allocation), HSN (hopping sequence number), and MAIO (mobile allocation index offset). The ratio of number of the TRXs to that of the available frequency hopping is FR LOAD (generally, it is smaller than 50%). A1 A2 A3 A1 A2 A3 A1 A2 A3 A1 A2 A3
20. 20. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page20 Example of 1 x 3 Frequency Reuse  If the available bandwidth is 10MHz ,the channel numbers are 45~94  For BCCH carriers, channel numbers is 81~94, frequency reuse pattern is 4×3  For TCH carriers, channel numbers is 45~80, frequency reuse pattern is 1×3  Because FR LOAD 1 to 2, if the bandwidth is 10MHz, the maximum base station type can be configured as S7/7/7. In this case, the frequency reuse degree is 7.14 Frequency group number Channel number MAIO A 80, 77, 74, 71, 68, 65, 62, 59, 56, 53, 50, 47 0, 2, 4,6, 8, 10 B 79, 76, 73, 70, 67, 64, 61, 58, 55, 52,49, 46 1, 3, 5, 7, 9, 11 C 78, 75, 72, 69, 66, 63, 60, 57, 54, 51, 48, 45 0, 2, 4, 6, 8, 10 space grouping Frequency group number Channel number MAIO A 80, 79, 78, 77, 76, 75, 74, 73,72, 71, 70, 69 0, 2, 4, 6, 8, 10 B 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57 0, 2, 4, 6, 8, 10 C 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45 0, 2, 4, 6, 8, 10 sequence grouping
21. 21. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page21 Example of 1×3 Frequency Reuse  Suppose 900 band: 96～124  BTS configuration: S3/3/3  BCCH layer: 96～109 reuse pattern: 4×3  TCH layer: 110～124 reuse pattern: 1×3
22. 22. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page22 TCH Consecutive Allocation Scheme MAIO CELL1(MA1) 110 111 112 113 114 0,2 CELL2(MA2) 115 116 117 118 119 0,2 CELL3(MA3) 120 121 122 123 124 0,2 MA1 MA2 MA3 Cell1 Cell2Cell3 MA1 MA2 MA3 Cell1 Cell2Cell3 MA1 MA2 MA3 Cell1 Cell2Cell3 (110,112) (110,112) (110,112) (115,117) (115,117) (115,117) (120,122) (120,122) (120,122)
23. 23. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page23 TCH Interval Allocation Scheme MAIO CELL1(MA1) 110 113 116 119 122 0,1 CELL2(MA2) 111 114 117 120 123 2,3 CELL3(MA3) 112 115 118 121 124 4,0 MA1 MA2 MA3 Cell1 Cell2Cell3 MA1 MA2 MA3 Cell1 Cell2Cell3 MA1 MA2 MA3 Cell1 Cell2Cell3 (110,113) (110,113) (110,113) (117,120) (117,120) (117,120) (124,112) (124,112) (124,112)
24. 24. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page24 The Characteristics of the 1 x 3  The frequencies are more tightly reused, so the network capacity is great.  When planning a network, only need to plan BCCH, while it’s unnecessary to re- plan frequencies. So the efficiency for network planning is high.  Wideband combiner must be used, but the cavity combiner with frequency selectivity is inapplicable.  Co-channel and neighbor channel interference increases as the frequency reuse distance decreases.  RF hopping must be used, and the channel numbers participating frequency hopping is twice that of the number of carriers at least.  In actual conditions, BCCH cannot take measures, such as RF hopping, DTX, and power control, therefore, in order to ensure network quality, BCCH can only use the looser 4 x 3 frequency reuse pattern.
25. 25. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page25 Example of 1 x 1 Frequency Reuse  One cell of one base station forms a frequency reuse cluster  If the available bandwidth is 6MHz ,the channel numbers are 96~124  For BCCH carriers, channel numbers is 111~124, frequency reuse pattern is 4×3  For TCH carriers, channel numbers is 96~110, frequency reuse pattern is 1×1  the maximum base station type can be configured as S4/3/3 under 1 x 1 frequency reuse pattern. In this case, the frequency reuse degree is 7.25/9.67/9.67, so the average value is 8.86.  Therefore, the maximum base station configuration under 1 x 1 frequency reuse pattern is the same as that under 1 x 3 frequency reuse space grouping pattern, so is the network capacity. Frequency group number Channel number MAIO A 96,97,98,99,100,101,102,103,104,105,106,107,108,109,110 0,2,4 B 96,97,98,99,100,101,102,103,104,105,106,107,108,109,110 6,8 C 96,97,98,99,100,101,102,103,104,105,106,107,108,109,110 10,12
26. 26. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page26 BCCH14+TCH36： 1BCCH+3TCH 1BCCH+3TCH 1BCCH+3TCH 1BCCH+12TCH 1BCCH+12TCH 1BCCH+12TCH 4×3 1×3 1×3 and 1×1 1BCCH+TCH 1BCCH+36TCH 1BCCH+36TCH 1×1
27. 27. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page27 TRX1 TRX2 ... TRX7 TRX8 TRX9... TRX14 TRX15 TRX16...TRX21 TRX1 TRX2 ... TRX7 TRX8 TRX9... TRX14 TRX15 TRX16...TRX21 The red items are BCCH RCs Illustration of 1×3 or 1×1
28. 28. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page28 Contents 1. Frequency Planning 2. Normal Frequency Reuse Technology 3. Tight Frequency Reuse 4. Concentric Cell Technology 5. Multiple Reuse Pattern Technology 6. Frequency Hopping
29. 29. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page29 Conception of MRP Technology  According to multiple reuse pattern (MRP), the carriers are divided into several groups.  The carries in each group work as an independent layer, and each layer uses a different frequency reuse pattern.  During frequency planning, configure the carriers layer by layer, with reuse density increases layer by layer, as shown in the next slide.
31. 31. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page31  Capacity increase when reuse density is multiplied:  Supposing there are 300 cells  Bandwidth: 8 MHz (40 frequency)  Normal 4×3 reuse: reuse density=12  Network capacity = (40/12)×300 = 1000 TRX  Multiple reuse: BCCH layer: re-use =12, (14 frq.) Normal TCH layer: re-use =10, (20 frq.) Aggressive TCH layer: re-use = 6, (6 frq.)  Network capacity = (1 +2 +1)×300 = 1200 TRX Example of MRP
32. 32. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page32 Example of MRP  Capacity increase when reuse density is multiplied:  Supposing there are 300 cells  Bandwidth: 8 MHz (40 frequency)  Normal 4×3 reuse: reuse density=12  Network capacity = (40/12)×300 = 1000 TRX  Multiple reuse: BCCH layer: reuse density=12, (14 frequency) Normal TCH layer: reuse density=10, (20 frequency) Aggressive TCH layer: reuse density= 6, (6 frequency)  Network capacity = (1 +2 +1)×300 = 1200 TRX
33. 33. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page33 Contents 1. Frequency Planning 2. Normal Frequency Reuse Technology 3. Tight Frequency Reuse 4. Concentric Cell Technology 5. Multiple Reuse Pattern Technology 6. Frequency Hopping
34. 34. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page34 Conception of Concentric Cell Technology  In the GSM network, concentric cell technology is used to divide the service area into two parts: overlaid and underlaid.  Essentially, the concentric cell technology concerns channel allocation and handover, but when combining this technology with various frequency planning technologies, both expand network capacity can be improved network quality. Overlaid-cell Underlaid-cell
35. 35. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page35 Overlaid/Underlaid Frequency Configuration Super fn Regular fm Regular fm Regular fm Super fn BCCH 15f Regular 24f Super 12f BCCH TRX reuse density: 12 Regular TCH TRX reuse density: 12 Super TCH TRX reuse density: 6 Super fn
36. 36. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page36 Conception of Concentric Cell Technology  Generally, 4 x 3 frequency reuse pattern is used for the underlaid. For overlaid, the frequency reuse patterns, such as 3 x 3, 2 x 3, or 1 x 3, are used. Therefore, all carriers can be divided into two groups, one for underlaid, and the other one for overlaid. Underlaid Overlaid
37. 37. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page37 Contents 1. Frequency Planning 2. Normal Frequency Reuse Technology 3. Tight Frequency Reuse 4. Concentric Cell Technology 5. Multiple Reuse Pattern Technology 6. Frequency Hopping
38. 38. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page38 Contents 6. Frequency Hopping 6.1 Classification of hopping 6.2 Advantages of hopping 6.3 Parameter of hopping 6.4 Collocation of hopping data
40. 40. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page40 Advantages of Hopping  Get an agreeable radio environment.  Provide a similar communication quality for every user.  Tighter reuse patterns are possible to be used for larger capacity.
43. 43. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page43 Classification of Hopping  According to implementation mode  Base-band hopping  RF hopping  According to the minimum hopping time unit  Timeslot hopping  Frame hopping
45. 45. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page45 Base Band Hopping Principle  BCCH carrier attends hopping, on which TS0 can not attend hopping No Hopping TRX0 TRX1 TRX2 TRX3 TS 0 TS 1 TS 2 TS 3 TS 4 TS 5 TS 6 TS 7 ARFCN 5(BCCH carrier) 10(TCH carrier) 15(TCH carrier) 20(TCH carrier) MA={5,10,15,20}MA={10,15,20}
46. 46. Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved. Page46 Base Band Hopping Principle  BCCH carrier does not attends hopping TRX0 TRX1 TRX2 TRX3 TS 0 TS 1 TS 2 TS 3 TS 4 TS 5 TS 6 TS 7 MA={10,15,20} ARFCN 5(BCCH carrier) 10(TCH carrier) 15(TCH carrier) 20(TCH carrier) No Hopping No Hopping No Hopping No Hopping No Hopping No Hopping No Hopping No Hopping