Modul 5 bss parameter

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Explain about parameter GSM that can be optimized. Like handover parameter, access parameter, etc

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Modul 5 bss parameter

  1. 1. GSM-GPRS Operation BSS Parameter Module 5
  2. 2. 2 Outline  BSS Parameters Structure  BTS Parameters  MS Mode  Idle Mode  Cell Selection  Cell Reselection  Dedicated Mode  Handover  Power Control  BSC parameters kris.sujatmoko@gmail.com
  3. 3. GSM-GPRS Operation BSS Parameters BTS Parameters BSC Parameters
  4. 4. 4 BSS Parameters Structure kris.sujatmoko@gmail.com
  5. 5. 5 BSS Parameters Structure (2)  Base Station Controller (BSC)  The BSC object contains BSC-specific radio network data.  BCCH Allocation Frequency List (BA)  The BA object contains data for building the BCCH allocation.  Mobile Allocation Frequency List (MA)  The MA object contains data for building the mobile allocation for RF hopping.  Base Control Function (BCF)  The BCF object contains data that is specific for the O&M functions of the BTS.  Base Transceiver Station (BTS)  The BTS object contains BTS-specific radio network data.  Handover Control (HOC)  The handover control object contains parameters which control the handover procedure. kris.sujatmoko@gmail.com
  6. 6. 6 BSS Parameters Structure (3)  Power Control (POC)  The power control object contains parameters which control the power control procedure.  Adjacent Cell (ADJC)  The adjacent cell object contains a description of the adjacent cell of the BTS.  Transceiver (TRX)  The TRX object contains TRX-specific data.  Radio Time Slot (RTSL)  The radio time slot object contains parameters for the physical radio time slot.  Frequency Hopping System (FHS)  The frequency hopping system object contains hopping parameters for the BTS. kris.sujatmoko@gmail.com
  7. 7. GSM-GPRS Operation BTS Parameters
  8. 8. 8 BTS - Parameter kris.sujatmoko@gmail.com
  9. 9. GSM-GPRS Operation Parameter Related To Idle Mode
  10. 10. 10 MS Mode Search for Frequency Correction Burst Search for Synchronisation sequence Read System Informations listen for Paging send Access burst wait for signalling channel allocation Call setup traffic channel is assigned Conversation Call release FCCH SCH BCCH PCH RACH AGCH SDCCH FACCH TCH FACCH idle mode “off” state dedicated mode idle mode kris.sujatmoko@gmail.com
  11. 11. 11 Idle Mode – Cell Selection  Radio constraints:  The MS uses a "path loss criterion" parameter C1 to determine whether a cell is suitable to camp on [GSM 03.22]  C1 depends on 4 parameters:  Received signal level (suitably averaged)  The parameter rxLevAccessMin, which is broadcast on the BCCH, and is related to the minimum signal that the operator wants the network to receive when being initially accessed by an MS  The parameter msTxPwrMaxCCH, which is also broadcast on the BCCH, and is the maximum power that an MS may use when initially accessing the network  The maximum power of the MS. kris.sujatmoko@gmail.com
  12. 12. 12 Idle Mode – Cell Selection (2)  Path loss criterion parameter C1 used for cell selection and reselection is defined by :  C1 = (A - Max(B,0))  where  A = Received Level Average - rxLevAccessMin  B = msTxPwrMaxCCH – P  Except for the class 3 (4 watts) DCS 1 800 MS where :  B = msTxPwrMaxCCH + POWER OFFSET - P kris.sujatmoko@gmail.com
  13. 13. 13 Idle Mode – Cell Selection (3)  rxLevAccessMin = Minimum received level at the MS required for access to the system.  msTxPwrMaxCCH = Maximum TX power level an MS may use when accessing the system until otherwise commanded.  POWER OFFSET = The power offset to be used in conjunction with the MS TXPWR MAX CCH parameter by the class 3 DCS 1 800 MS.  P = Maximum RF output power of the MS. kris.sujatmoko@gmail.com
  14. 14. 14 Idle Mode – Cell Selection (4)  Procedure kris.sujatmoko@gmail.com
  15. 15. 15 Idle Mode – Cell Selection (5)  Example  C1(cell_A) = AV_RXLEV - rxLevAccessMin - Max(0, msTxPwrMaxCCH – max output power of MS)  C1(cell_A) = -80dBm – (-100dBm) – max(0, 36dBm – 33dBm)  C1(cell_A) = 17 > 0  C1(cell_B) = -82dBm – (-105dBm) – max(0, 33dBm – 33dBm)  C1(cell_B) = 23 > C1(cell_A)  Thus MS camps on cell_B kris.sujatmoko@gmail.com
  16. 16. 16 Idle Mode – Cell Reselection  Why C2 ?  Cell Prioritisation  As a means of encouraging MSs to select some suitable cells in preference to others  Example:  In dualband network--to give different priorities for different band  In multilayer--to give priority to microcell for slow moving traffic  Any other special case where specific cell required higher priority than the rest kris.sujatmoko@gmail.com
  17. 17. 17 Idle Mode – Cell Reselection (2)  How the MS knows?  cellReselectOffset, penaltyTime, temporaryOffset are cell reselection parameters  These parameters are broadcast on the cell BCCH when cellReselectparamInd is set to yes  Cell Reselection Strategy:  Positive offset--encourage MSs to select that cell  Negative offset--discourage MSs to select that cell for the duration penaltyTime period kris.sujatmoko@gmail.com
  18. 18. 18 Idle Mode – Cell Reselection (3)  MS will calculate the C1 and C2 for the serving cell, every 5 s  MS will calculate the C1 and C2 for the neighbour cells, every 5 s  Cell re-selection is needed if :  Path Loss criterion C1 < 0 for cell camped on, for more than 5 sec  There is DL signaling failure  The cell camped on has been barred  The is a better cell in terms of C2 criterion kris.sujatmoko@gmail.com
  19. 19. 19 Idle Mode – Cell Reselection With C2 (1) kris.sujatmoko@gmail.com
  20. 20. 20 Idle Mode – Cell Reselection With C2 (2)  For penaltyTime = 640 seconds,  C2 = C1 – cellReselectOffset  For penaltyTime < 640 seconds,  C2 = C1 + cellReselectOffset – temporaryOffset for T <= penaltyTime  C2 = C1 + cellReselectOffset for T > penaltyTime kris.sujatmoko@gmail.com
  21. 21. 21 Idle Mode – Cell Reselection With C2 (3) kris.sujatmoko@gmail.com
  22. 22. 22 Idle Mode – Cell Reselection With C2 (3) kris.sujatmoko@gmail.com
  23. 23. 23 Cell Selection Case Study  A dualband network, 1800 layer is preferred during call setup  Why?  To relieve blocking in 900 layer  To absorb traffic from 900 layer  Strategy?  Use C2 parameters  How?  Minimising massive BSS parameters change in the existing 900 layer  Traffic is increase in a control manner  Only 1800 layer required BSS parameter change kris.sujatmoko@gmail.com
  24. 24. 24 Cell Selection Case Study (2)  How to set?  Cell Reselection Parameters activated in 1800 layer  900 layer remain unchanged--operation as normal  What value?  reselectOffset is initial set at low value during initial stage and further optimised in later stage kris.sujatmoko@gmail.com
  25. 25. 25 Cell Selection Case Study (3)  The Rationale?  cellReselectParamInd--YES  No C2 parameters will be broadcast on cell BCCH if this parameter is not turned on  cellReselectOffset = 8 dB  The 1800 layer having a C2 of 8 dB higher than C1 of 900 after the penaltyTime expires  PenaltyTime = 20 seconds  Assume 1800 cell radius 400 meters  Fast moving traffic speed 80 km/h  A MS takes approximately 20 seconds to cross a cell 1800 cell  Because the initial coverage for 1800 is not contiguous, the fast moving traffic is not allowed to move to 1800 layer kris.sujatmoko@gmail.com
  26. 26. 26 Cell Selection Case Study (4)  The Rationale?  PenaltyTime = 20 seconds  During the penaltyTime period, the fast moving MS will set up call on 900 layer  Slow moving traffic will set up call on 1800 layer  temporaryOffset = 10 dB  This value should be set higher than cellReselectOffset value  In order to have a negative offset (with reference to 1800 C1 value) during the penaltyTime period kris.sujatmoko@gmail.com
  27. 27. 27 Cell Selection Case Study (5)  The Rationale?  cellBarQualify = NO  Cell selection priority is normal status  If set to YES, cellBarred parameter can be overwrite and cell selection priority will become low kris.sujatmoko@gmail.com
  28. 28. 28 Cell Selection Case Study (6)  The Scenario:  GSM900: rxLevAvg = -75dBm; rxLevAccessMin = -97dBm  DCS1800: rxLevAvg = -80dBm; rxLevAccessMin = -95dBm  For serving GSM900 cell,  C2 = C1 = rxLev – rxLevAccessMin – max ([msTxPowerMaxCCH - max RF output of MS], 0)  C1 = -75dBm – (-97dBm) – max([33 – 33], 0)  C1 = 22 dB kris.sujatmoko@gmail.com
  29. 29. 29 Cell Selection Case Study (7)  The Scenario:  For non-serving DCS1800 cell,  C1 = rxLev – rxLevAccessMin – max ([msTxPowerMaxCCH – maxRF output of MS], 0)  C1 = -80dBm – (-95dBm) – max([30 – 30], 0)  C1 = 15 dB  During the penalty time period of 20 seconds; before the penalty time expires  C2 = C1 + cellReselectOffset – temporaryOffset = 15 + 8 –10 = 13dB < C2 for GSM900 cell (= 22dB)  MS stays in GSM900 layer during this period kris.sujatmoko@gmail.com
  30. 30. 30 Cell Selection Case Study (8)  The Scenario:  After the penalty time period of 20 seconds expires  C2 = C1 + cellReselectOffset = 15 + 8 = 23dB > C2 for GSM900 cell (= 22dB)  MS reselects DCS1800 layer after penalty time expires kris.sujatmoko@gmail.com
  31. 31. 31 Cell Selection Case Study (9) kris.sujatmoko@gmail.com
  32. 32. 32 Cell Selection Case Study (10) kris.sujatmoko@gmail.com
  33. 33. 33 Cell Selection Case Study (11) kris.sujatmoko@gmail.com
  34. 34. 34 Idle Mode – Cell Reselection Hysteresis  Cell Reselection Hysteresis  MS is moving in a border area between location areas  MS might repeatedly change between cell of different location areas  Each change of location area requires a location update  LU causes  Causes heavy signalling load  Increases risk of paging message being lost  To prevent this, cell reselect hysteresis is used  How this parameter works?  A cell in a different location area is only selected if it is “better” than all the cell in the current LA by at least the value of cellReselectHysteresis  In term of path loss criterion kris.sujatmoko@gmail.com
  35. 35. 35 Idle Mode – Cell Reselection Hysteresis(2)  Cell Reselection Hysteresis  What value to set?  Typical value is 6~8 dB  Example:  A static class 4 MS camping on cell 1 in idle mode.  The MS monitor the BCCH of cell 1 and cell 2 and measures the following levels  rxLevAvg = -80dBm in cell 1  rxLevAvg = -86dBm from neighbour cell 2  The following parameters are set: kris.sujatmoko@gmail.com
  36. 36. 36 Idle Mode – Cell Reselection Hysteresis(3)  Does the MS perform cell reselect?  If cell 1 and cell 2 belong to the same LA  If the cell 1 and cell 2 belong to different LAs kris.sujatmoko@gmail.com
  37. 37. 37 Idle Mode – Cell Reselection Hysteresis(4)  What are the conditions?  For the same LA:  C1 (cell 2) > C1 (cell 1)  For the different LA:  C1 (cell 2) > C1 (cell 1) + cellReselectHysteresis  C1 (cell 1) = rxLevAvg – rxLevAccessMin – max ([msTxPowerMaxCCH – max RF output of MS], 0)  C1 (cell 1) = -80dBm – (-100dBm) – max([36 – 33], 0)  C1 (cell 1) = 17 dB  C1 (cell 2) = rxLevAvg – rxLevAccessMin – max ([msTxPowerMaxCCH – max RF output of MS], 0)  C1 (cell 2) = -84dBm – (-104dBm) – max([33 – 33], 0)  C1 (cell 2) = 20 dB kris.sujatmoko@gmail.com
  38. 38. 38 Idle Mode – Cell Reselection Hysteresis(5)  C1 (cell 2) = 20 dB > C1 (cell 1) = 17 dB  For the same LA:  C1 (cell 2) > C1 (cell 1)  cell reselection  For the different LA:  C1 (cell 2) < C1 (cell 1) + cellReselectHysteresis  No cell reselection kris.sujatmoko@gmail.com
  39. 39. 39 Idle Mode – Cell Reselection Hysteresis(6) kris.sujatmoko@gmail.com
  40. 40. GSM-GPRS Operation Parameter Related To Dedicated Mode
  41. 41. 41 Dedicated Mode  Handover  Power Control kris.sujatmoko@gmail.com
  42. 42. GSM-GPRS Operation Handover Parameters
  43. 43. 43 Handover Parameter kris.sujatmoko@gmail.com
  44. 44. 44 Handover Design (1)  Handover definition:  A mechanism that transfers an ongoing call from one cell to another as a user moves through a coverage area of a GSM system  Trends:  Smaller cells to meet the demands for increased capacity  number of cell boundary crossing increase  Impact:  Network Resource: switching load  Delay  Quality of Service kris.sujatmoko@gmail.com
  45. 45. 45 Handover Design (2)  Network resource:  Minimising number of HO  minimising switching load  QoS :  Minimising delay  minimises co-channel interference  Challenge  optimium HO parameters settings using the existing HO algorithm so that the perceived QoS does not degrade kris.sujatmoko@gmail.com
  46. 46. 46 Handover Design (3) – Guidelines  General HO Design Guidelines  HO design involves setting of:  HO parameters  GenHandoverRequestMessage in BSC parameter  MsTxPwrMax in BTS parameter  PcLowerThresholdLevDL/UL in power control parameter  hoMargin in adjacency parameter  HO objectives:  maintenance of connection in case of cell change (movement)  channel change in case of severe disturbance (interference)  design of cell borders and radio network structure kris.sujatmoko@gmail.com
  47. 47. 47 Handover Design (4)  HO is divided into several sub processes kris.sujatmoko@gmail.com
  48. 48. 48 Handover Design (5) kris.sujatmoko@gmail.com
  49. 49. 49 Handover Design (6)  HO Sub Processes Flow kris.sujatmoko@gmail.com
  50. 50. 50 Handover Design (7)  Handover performance metrics used to evaluate HO performance:  Call blocking probability -the probability that a new call attempt is blocked  Handover blocking probability - the probability that a handover attempt is blocked  Handover probability - the probability that, while communicating with a particular cell, an ongoing call requires a handover before the call terminates. This metric translates into the average number of handovers per call  Call dropping probability - the probability that a call terminates due to a handover failure. This metric can be derived directly from the handover blocking probability and the handover probability kris.sujatmoko@gmail.com
  51. 51. 51 Handover Design (8)  Probability of an unnecessary handover - the probability that a handover is stimulated by a particular handover algorithm when the existing radio link is still adequate  Rate of handover - the number of handovers per unit time. Combined with the average call duration, it is possible to determine the average number of handovers per call, and thus the handover probability.  Duration of interruption - the length of time during a handover for which the mobile terminal is in communication with neither base station. This metric is heavily dependent on the particular network topology and the scope of the handover  Delay -the distance thc mobile moves from the point at which the handover should occur to the point at which it does kris.sujatmoko@gmail.com
  52. 52. 52 Handover Design (9) kris.sujatmoko@gmail.com
  53. 53. 53 Handover Design (10)  Relative signal strength:  HO triggered at point A  Unnecessary HO when the serving cell signal is still adequate  Relative signal strength with threshold:  If threshold set at T1, same as relative signal strength trigger point A  If threshold set at T2, HO is delayed, occurs at point B  If threshold set at T3, delay too long# may result in dropped call and suffers co-channel interference kris.sujatmoko@gmail.com
  54. 54. 54 Handover Design (11)  Relative signal strength with margin:  Triggered only when the target cell signal strength is stronger than the serving cell by a margin h, point C  Prevent “ping-pong” effect  repeated HO between two cells due to rapid fluctuations in received signal from both cells  Unnecessary HO may occur if the serving cell is sufficiently strong  Relative signal strength with margin and threshold  Triggered when the serving cell signal drop below threshold and the target cell signal is stronger by a margin  Occurs at point C if the threshold is set at T1 and T2  Occurs at point D if threshold is set at T3 kris.sujatmoko@gmail.com
  55. 55. 55 Handover Design (12)  HO initiation criteria based on 4 variables:  Averaging window size  Measurement value weighting  Threshold level  Margin kris.sujatmoko@gmail.com
  56. 56. 56 Handover Design (13)  Parameter to enable different type Of HO : kris.sujatmoko@gmail.com
  57. 57. 57 Handover Design (14) – HO Priority  RR-radio resource:  target cells are ranked according to radio link properties and  priority levels  Imperative:  target cells are ranked according to radio link properties  priority levels are not used kris.sujatmoko@gmail.com
  58. 58. 58 Handover Design (15) – HO Priority kris.sujatmoko@gmail.com
  59. 59. 59 Handover Causes And Decisions (1) kris.sujatmoko@gmail.com
  60. 60. 60 Handover Causes And Decisions (2) kris.sujatmoko@gmail.com
  61. 61. 61 Handover Regions (1) – Threshold Setting kris.sujatmoko@gmail.com
  62. 62. 62 Handover Regions (2) – Handover Level Threshold kris.sujatmoko@gmail.com
  63. 63. 63 Handover Flow kris.sujatmoko@gmail.com
  64. 64. 64 Handover Scenario (1)  HO Thresholds:  Set to meet the optimum HO performance  2 Scenarios to be considered:  Noise Limited  Interference Limited  MS behaves differently in the above 2 scenarios kris.sujatmoko@gmail.com
  65. 65. 65 Handover Scenario (2)  HO Thresholds parameters and values kris.sujatmoko@gmail.com
  66. 66. 66 Handover – Noise Limited Scenario  Noise Limited Scenario  Large cell with low traffic load, specially in rural area  rxLev at cell border is just a few dB higher than receiver reference sensitivity  Main Handover criteria is level criteria  Receiver Reference Sensitivity according to GSM 05.05 kris.sujatmoko@gmail.com
  67. 67. 67 Handover – Noise Limited Scenario (2)  Noise Limited Scenario  Imperative to set the optimum values to avoid “forward-back” HO  General guideline:  rxLevMinCell – hoThresholdsLevDL = level hysteresis > 0 (+4dB..10dB)  rxLevMinCell > hoThresholdsLevDL + level hysteresis and  hoThresholdsLev > MS sensitivity + 3 dB  only DL is mentioned for illustration; in actual parameters planning, both UL/DL kris.sujatmoko@gmail.com
  68. 68. 68 Handover – Noise Limited Scenario (3) kris.sujatmoko@gmail.com
  69. 69. 69 Handover – Noise Limited Scenario (4) kris.sujatmoko@gmail.com
  70. 70. 70 Handover – Noise Limited Scenario (5) kris.sujatmoko@gmail.com
  71. 71. 71 Handover – Noise Limited Scenario (6) kris.sujatmoko@gmail.com
  72. 72. 72 Handover – Interference Limited Scenario (1)  Interference Limited Scenario  Small cell with high traffic load, especially in urban area  rxLev at cell border is significant higher than the receiver sensitivity  C/I is not much higher than the reference interference level  Main Handover criteria is power budget criteria  Receiver Reference Interference Level according to GSM 05.05 kris.sujatmoko@gmail.com
  73. 73. 73 Handover – Interference Limited Scenario (2)  Interference Limited Scenario  Better cell criteria should be the main HO criteria  Power budget HO guarantee that the MS is served by the cell with lowest path loss  Thus, higher chance for power control to reduce interference kris.sujatmoko@gmail.com
  74. 74. 74 Handover – Interference Limited Scenario (3)  General guideline:  hoMarginPBGT (cell1 cell2) + hoMarginPBGT (cell2 cell1) = PBGT hysteresis > 0 (+6dB..12dB)  Normally hoMarginPBGT is set symmetrically  Low hoMarginPBGT values  high “forward-backward” HO rate  High hoMarginPBGT values  low “forward-backward” HO rate  Unsymmetrical hoMarginPBGT value is set to adapt cell service area to traffic load  Increases one cell service area and at the same time reducing its corresponding neighbour cell service area kris.sujatmoko@gmail.com
  75. 75. 75 Handover – Interference Limited Scenario (4)  Power Budget Hysteresis kris.sujatmoko@gmail.com
  76. 76. 76 Handover – Interference Limited Scenario (5) kris.sujatmoko@gmail.com
  77. 77. 77 Handover – Interference Limited Scenario (6)  General guideline:  Symmetrical hoMarginPBGT = 6dB: point x and a  Unsymmetrical hoMarginPBGT (cell1  cell2) = 9dB and hoMarginPBGT (cell2  cell1) = 3dB  PBGT hysteresis = 12dB  Point y and b  Cell2 service area reduced from point x to y  Cell1 service area increased from point a to b kris.sujatmoko@gmail.com
  78. 78. 78 Handover – Interference Limited Scenario (7) kris.sujatmoko@gmail.com
  79. 79. 79 Other HO Types And Features kris.sujatmoko@gmail.com
  80. 80. 80 Umbrella Handover  The Objective:  To serve the target traffic more efficiently  Umbrella HO has priority over power budget HO  The mapping table for gsmMacrocellThreshold and gsmMicrocellThreshold kris.sujatmoko@gmail.com
  81. 81. 81 Umbrella Handover (2)  What does the table mean?  Example:  If you set the gsmMocrocellThreshold** smaller than the MS class maximum output power, the MS is only allowed to HO to macrocell  At the same cell, its adjacency parameter msTxPwrMaxCell(n) should be set smaller than gsmMacrocellThreshold Note ** gsmMacrocellThreshold is a BSC parameter, it need additional adjacency parameter to control per adjacency basis kris.sujatmoko@gmail.com
  82. 82. 82 Umbrella HO Algorithm kris.sujatmoko@gmail.com
  83. 83. 83 Umbrella Handover (3) kris.sujatmoko@gmail.com
  84. 84. 84 Umbrella Handover (4)  When AV_RXLEV_NCELL(n) = -75dBm  A MS class 4 in dedicated mode is in macrocell  1’ AV_RXLEV_NCELL(n) > hoLevUmbrella(n)  (MS class 4 = 33dBm) <= (gsmMicrocellThrsehold = 33dBm) and  (MsTxPwrMaxCell(n) = 33dBm) <= (gsmMicrocellThreshold = 33dBm)  Umbrella HO to microcell occurs  When MS is at microcell border, av_rxLev = -98dBm and av_rxLev_cell(n) = - 82dBm  1. av_RxLevUL/DL < hoThresholdsLevUL/DL  2. AV_RXLEV_NCELL(n) – av_RxLevDL – (btsTxPwrMax – BTS_TXPWR) > hoMarginLev(n) kris.sujatmoko@gmail.com
  85. 85. 85 Umbrella Handover (5)  When MS is at microcell border, av_rxLev = -98dBm and AV_RXLEV_NCELL(n) = -82dBm  1. av_RxLevDL < hoThresholdsLevDL -98 dBm < -95 dBm  2. AV_RXLEV_NCELL(n) – av_RxLevDL – (btsTxPwrMax – BTS_TXPWR) > hoMarginLev(n) -82 – (-98) – (0 – 0) = 16 dB > 3 dB  HO due to level kris.sujatmoko@gmail.com
  86. 86. 86 Handover Due To Fast/Slow MS Speed  2 possibilities:  MS speed in relation to cell size  Measured MS speed  Both need AdjCellLayer(n) and hoLevelUmbrella(n) parameters ** Note ** see detail HO due to fast/slow moving MS algorithm kris.sujatmoko@gmail.com
  87. 87. 87 Handover Due To Fast/Slow MS Speed Algorithm kris.sujatmoko@gmail.com
  88. 88. 88 Handover Due To Fast/Slow MS Speed (2) kris.sujatmoko@gmail.com
  89. 89. 89 Handover Due To Fast/Slow MS Speed (3)  MS speed in relation to cell size  Parameters are set per adjacency basis  From Macro to micro  Counter for each adjacent microcell  +2 for each measurement >= rxLevMinCell(n)  –1 for each measurement < rxLevMinCell(n) or no measurement kris.sujatmoko@gmail.com
  90. 90. 90 Handover Due To Fast/Slow MS Speed (4)  How to set fastMovingThreshold?  if microcell radius is about 200 meters, taking 2.5 m/s as slow moving limit; thus  total time to cross the microcell is 200/2.5 = 80 seconds  if averaingWindowSizeAdjCell is set to 6 SACCH, this equal to about 3 seconds for each measurement  it take 5 seconds to decode an adjacent cell BSIC, thus total measurements is (5 + 3* measurements) = 80 seconds  thus total measurements are (80-5)/3 = 25 number of measurements  the fastMovingThreshold = 25*2 = 50 (because counter increases by 2 for each measurement) kris.sujatmoko@gmail.com
  91. 91. 91 Handover Due To Fast/Slow MS Speed (5)  When the counter > fastMovingThreshold = 50; and  AV_RXLEV_NCELL(n) > hoLevUmbrella (n) = -80dBm  Umbrella HO due to slow moving MS  ? what is the speed limit if fastMovingThreshold = 24 for a cell radius of 205 meters ?  24 = 12 measurements; 12*3 + 5 = 41 seconds; 200 meters/ 41 = 4.8 m/s kris.sujatmoko@gmail.com
  92. 92. 92 Handover Due To Fast/Slow MS Speed (6) kris.sujatmoko@gmail.com
  93. 93. 93 Handover Due To Fast/Slow MS Speed (7)  Measured MS speed  Related parameters:  Slow moving MS to lower layer adjacent cells (lowerSpeedLimit)  Fast moving MS to upper layer adjacent cells (upperSpeedLimit)  One unit value of lowerSpeedLimit upperSpeedLimit equal to 2km/h kris.sujatmoko@gmail.com
  94. 94. 94 Handover – MS-BTS Distance  To prevent MS from exceeding cell boundary  Related Parameters:  msDistanceBehaviour  0 : Release immediately  1 - 60 : Release after certain time 1 - 60 s, try imperative handover during that time  255 : No release, only imperative handover attempt kris.sujatmoko@gmail.com
  95. 95. 95 Handover – MS-BTS Distance (2)  msDistanceHoThresholdParam  1 step size correlates to 550 meters  this parameter value depends on the designed cell radius  if the value is set to 2, the maximum cell radius for the MS is 2*550 = 1100meters before the imperative HO is attempted in the 30 seconds period set in the parameter msDistanceBehaviour; if HO execution fails; the call will be terminated  enableMSDistanceProcess  Set to yes to activate this feature kris.sujatmoko@gmail.com
  96. 96. 96 Traffic Reason Handover  TRHO effectively  reduces the service area of a congested cell and  Increases the service area of the under-utilised target cells  HO is triggered with amhTrhopPbgtMargin instead of hoMarginPBGT  General guideline:  Target cell minimum access level should be set higher to avoid bad DL rxQual after HO  amhTrhoPbgtMargin should be much lower than hoMarginPBGT kris.sujatmoko@gmail.com
  97. 97. 97 TRHO Algorithm kris.sujatmoko@gmail.com
  98. 98. 98 Traffic Reason Handover (2) – TRHO Parameter  BSC Parameter  BTS Parameter kris.sujatmoko@gmail.com
  99. 99. 99 Traffic Reason Handover (3) – TRHO Parameter  Adjacency Parameters  amhTrhoPbgtMargin(n) should be set lower than hoMarginPBGT  trhoTargetLevel(n) should be set higher than rxLevMinCell(n) to ensure only good adjacent cell is used kris.sujatmoko@gmail.com
  100. 100. 100 Traffic Reason Handover (4) kris.sujatmoko@gmail.com
  101. 101. 101 Directed Retry (DR)  A transition (handover) from a SDCCH in one cell to a TCH in another cell during call setup due to unavailability of an empty TCH within the first cell  To control traffic distribution between cells to avoid a call rejection  Can be used for both MOC and MTC  Setting guidelines:  drThreshold should be higher than rxLevMinCell; else the improved target cell selection criteria will be ignored even drMethod = 1 kris.sujatmoko@gmail.com
  102. 102. 102 Directed Retry (2) – Parameter Related kris.sujatmoko@gmail.com
  103. 103. 103 Directed Retry (2) - Algorithm kris.sujatmoko@gmail.com
  104. 104. 104 Directed Retry (3)  Example kris.sujatmoko@gmail.com
  105. 105. 105 Directed Retry (4)  the BSC cannot start the target cell evaluation within 2 seconds period from the start of directed retry procedure is triggered  after 2 seconds, the BSC continues to evaluate the target cell until 6 seconds period expires and if no suitable target cells are available, directed retry will be aborted **  ** MS need at least 5 seconds to decode the neighbouring BSIC. Thus minimum maxTimeLimitDirectedRetry should be 5 seconds  cellType will be set based on the macro or micro cell in the network kris.sujatmoko@gmail.com
  106. 106. 106 Intelligent Directed Retry (IDR) kris.sujatmoko@gmail.com
  107. 107. 107 Queuing  Queuing Parameters :  If both queuePriorityUsed and msPriorityUsedInQueueing are used, queuePriorityUsed will be dominant factor  TimeLimitCall should be shorter than (maxTimeLimitDirectedRetry + minTimeLimitDirectedRetry) kris.sujatmoko@gmail.com
  108. 108. 108 Queuing (2)  MaxQueueLength: The parameter specifies the number of call attempts and handover attempts that can wait for a TCH release in a BTS. The value is the percentage of TRXs times 8  For a 4 TRXs cell, maxQueueLength = 50%, 50%*4*8 = 16 call attempts and HO attempts can wait for a TCH release in a cell  queuingPriorityHandover should be set higher than queuingPriorityCall  queuingPriorityCall should be set higher than queuePriorityNonUrgentHo  Non urgent HO: power budget HO, umbrella HO, slow moving MS HO and traffic reason HO  Urgent HO: quality and level reason HO kris.sujatmoko@gmail.com
  109. 109. 109 Queuing And Directed Retry kris.sujatmoko@gmail.com
  110. 110. 110 Queuing And Directed Retry (2)  Reference to Figure in previous slide,  Timing Diagram for Queuing and Directed Retry  the call setup will not be able to handover to directed retry if the timeLimitCall is longer than maxTimeDirectedRetry and the call will be terminated when the timeLimitCall expires kris.sujatmoko@gmail.com
  111. 111. GSM-GPRS Operation Power Control parameters
  112. 112. 112 Power Control (1) kris.sujatmoko@gmail.com
  113. 113. 113 Power Control (2)  Objective:  To adapt the transmit power of MS & BTS to reception conditions kris.sujatmoko@gmail.com
  114. 114. 114 Power Control (3)  Power control advantages:  reduction in MS average power consumption  reduction in overall network interference level  Power control is applied separately:  for uplink and downlink  each logical channel  Power control is not applied to:  downlink burst using the BCCH frequency kris.sujatmoko@gmail.com
  115. 115. 115 Power Control (4) - Algorithm kris.sujatmoko@gmail.com
  116. 116. 116 Power Control (5) - Regions kris.sujatmoko@gmail.com
  117. 117. 117 Power Control (6) - Implementation kris.sujatmoko@gmail.com
  118. 118. 118 Power Control (7)  Measurement preprocessing for power control:  for each call  UL and DL received signal level  UL and DL received signal quality  The measurements are made over each SACCH multiframe  104 TDMA frames (480 ms) for a TCH  102 TDMA frames (470,8 ms) for an SDCCH  every SACCH multiframe, MS sends in the next SDCCH message block the DL measurement on dedicated channel via the Measurement report message to the serving TRX of the BTS  serving TRX performs UL measurements on the dedicated channel kris.sujatmoko@gmail.com
  119. 119. 119 Power Control (8) – General POC Parameters kris.sujatmoko@gmail.com
  120. 120. 120 Power Control (9) – Step Size kris.sujatmoko@gmail.com
  121. 121. 121 Power Control (10) – Step Size Or Variable kris.sujatmoko@gmail.com
  122. 122. 122 Power Control (11) – POC Range kris.sujatmoko@gmail.com
  123. 123. 123 Power Control (12) – POC Range  If optimumRxLevUL feature is activated; i.e. set to –85 dBm;  alternative power control algorithm for MS will be used  pwrDecrLimitBand0  pwrDecrLimitBand1  pwrDecrLimitBand2  pwrdecrQualFactor kris.sujatmoko@gmail.com
  124. 124. 124 Power Control (13) - Power Decrement Band Setting kris.sujatmoko@gmail.com
  125. 125. 125 Power Control (14) - Power Decrement Band Setting  TRX parameter: optimumRxLevUL = -85 dBm  POC parameter:  pcUpperThresholdQualUL = 1  pwrDecrLimitBand0 = 10 dB  pwrDecrLimitBand1 = 8 dB  pwrDecrLimitBand2 = 6 dB  av_rxLev_UL = -80 dBm and av_rxQual_UL = 0  Power reduction is MS is 10 dB  av_rxLev_UL = -88 dBm and av_rxQual_UL = 0  Power reduction is MS is 4 dB kris.sujatmoko@gmail.com
  126. 126. 126 Power Control (15) - Power Decrement Band Setting kris.sujatmoko@gmail.com
  127. 127. 127 Power Control (16) - Power Decrement Band Setting  TRX parameter: optimumRxLevUL = -85 dBm  POC parameter:  pcUpperThresholdQualUL = 1  pwrDecrLimitBand0 = 10 dB  pwrDecrLimitBand1 = 8 dB  pwrDecrLimitBand2 = 6 dB  av_rxLev_UL = -80 dBm and av_rxQual_UL = 1  Power reduction is MS is 8 dB  av_rxLev_UL = -88 dBm and av_rxQual_UL = 1  Power reduction is MS is 2 dB kris.sujatmoko@gmail.com
  128. 128. 128 Power Control (17) - Power Decrement Band Setting  Averaging  Weighting is used when DTX is activated in the network kris.sujatmoko@gmail.com
  129. 129. 129 Power Control (18) - Power Decrement Band Setting  Weighting:  Window size = 8, weighting = 2 kris.sujatmoko@gmail.com
  130. 130. 130 Power Control (19) - Power Control Averaging  PC Priority:  PC due to Lower quality thresholds (UL and DL)  PC due to Lower level thresholds (UL and DL)  PC due to Upper quality thresholds (UL and DL)  PC due to Upper level thresholds (UL and DL) kris.sujatmoko@gmail.com
  131. 131. 131 Power Control (19) - Threshold kris.sujatmoko@gmail.com
  132. 132. 132 Power Control (20) - Threshold  Guideline:  thresholds setting is imperative to avoid undesirable ping pong effect of power control  if the pcUpperThresholdsLev is set too low, power down due to level at low rxlev will casue rxqual to deteriorate and subsequently power up occurs due to rxqual  rxqual improvement will lead to power down due to level again and the loop recurs kris.sujatmoko@gmail.com
  133. 133. 133 Power Control (21) - Regions kris.sujatmoko@gmail.com
  134. 134. 134 Power Control (22) - POC Threshold Values Example kris.sujatmoko@gmail.com
  135. 135. 135 Power Control (23) - MS Power Optimization  MS Power Optimisation  2 scenario:  During call setup  During handover  Use the optimized MS output power to reduce the uplink interference kris.sujatmoko@gmail.com
  136. 136. 136 Power Control (24) - MS Power Optimization  MS Power Optimisation  Without MS Power Optimisation, MS access the cell with maximum Tx power as specified by msTxPwrMaxCCH  During Call Setup:  Related Parameters: per TRX  Example:  MS_TXPWR_ OPT = MsTxPwrMax - MAX ( 0, (RXLEV_UL - OptimumRxLevUL) )  When RXLEV_UL = -80dBm  MS-TXPWR_OPT = 33 – max(0, (-80 + 85) = 28dBm  compare to maximum power 33 dBm kris.sujatmoko@gmail.com
  137. 137. 137 Power Control (25) - MS Power Optimization  MS Power Optimisation  During Handover:  Related Parameters: per Adjacency  Indicates the optimum UL RF signal level after Handover  Only for intra-BSC HO  When BSC calculates the optimized MS output power, it presumes that the UL signal level is equal to downlink signal level measured by MS  If the DL is stronger than UL by 6 dB, msPwrOPtLevel should be set 6 dB than the desired UL signal level kris.sujatmoko@gmail.com
  138. 138. 138 Power Control (26) - MS Power Optimization  MS Power Optimisation  During Handover:  If AV_RXLEV_NCELL(n) = -75dBm, and Set msPwrOptLevel = -80dBm  MS_TXPWR_ OPT(n) = msTxPwrMax(n) - MAX ( 0, (AV_RXLEV_NCELL(n) - msPwrOptLevel) )  MS_TXPWR_ OPT(n) = 33 – max ( 0, (-75 + 80) = 28 dBm  Thus MS uses 28 dBm output power instead of 33 dBm kris.sujatmoko@gmail.com
  139. 139. 139 Power Control And Handover Control  Rule of thumb:  POC should happen before HOC  2 ways to make this happens  Thresholds  Averaging windows size  RxLev Thresholds for POC > RxLev Thresholds for HOC  RxQual Thresholds for POC >= RxQual Thresholds for HOC  Window size (POC) <= window size (HOC) kris.sujatmoko@gmail.com
  140. 140. 140 Power Control And Handover Control (2)  Rxlev timing diagram kris.sujatmoko@gmail.com
  141. 141. 141 Power Control And Handover Control (3) - Example  RxLev Thresholds and window size:  For UL (refer to the figure in previous slide)  POC:  pcUpperThresholdsLevDL = -75 dBm, px = 2, nx = 3  pcLowerThresholdsLevDL = -89 dBm , px = 2, nx = 3  HOC:  hoThresholdsLevDL = -95 dBm, px = 3, nx = 4  What these setting mean? kris.sujatmoko@gmail.com
  142. 142. 142 Power Control And Handover Control (4) - Example  MS will power down if the 2 out of 3 av_RxLev_UL measurement samples is better than –75dBm  MS will power up if the 2 out of 3 av_RxLev_UL measurement samples is worse than –89dBm  If after powering up, the av_RxLev_UL is still lower than –95dBm with measurement sample 3 out of 4, HO will take place** **Note: this happen when the MS is at the cell border and is transmitting at the maximum power kris.sujatmoko@gmail.com
  143. 143. 143 Power Control And Handover Control (5)  RxQual timing diagram kris.sujatmoko@gmail.com
  144. 144. 144 Power Control And Handover Control (6)  POC And HO relationships kris.sujatmoko@gmail.com
  145. 145. 145 Power Control And Handover UL kris.sujatmoko@gmail.com
  146. 146. 146 Power Control And Handover UL (2) kris.sujatmoko@gmail.com
  147. 147. 147 Power Control And Handover DL kris.sujatmoko@gmail.com
  148. 148. 148 Power Control And Handover DL (2) kris.sujatmoko@gmail.com
  149. 149. GSM-GPRS Operation TRX parameters
  150. 150. 150 TRX Parameter kris.sujatmoko@gmail.com
  151. 151. 151 TRX Parameters kris.sujatmoko@gmail.com
  152. 152. 152 TRX parameters (2)  preferredBCCHMark:  BCCH is automatically configure to its original state after the TRX fault has been eliminated  Benefit of using TRX output power within a common cell  optimumRxLevUL:  Used in conjunction with POC –MS power optimisation  ETRX:  Extended TRX  A cell radius of an ordinary cell is 35 km.  Extended TRX can serve up to about 70 km  The implementation is based on one-BCCH (broadcast control channel) and two-TRX (transceiver) solution.  The normal coverage area is served with different TRXs than the extended coverage area. kris.sujatmoko@gmail.com
  153. 153. 153 TRX Parameters (3)  ETRX:  Timing of the TRXs which serve the extended coverage area is delayed so that they can serve the area beyond 35 km  Effectively 2 cell radius for a single cell  floatingMode:  TRX can be dynamically switched to operate in any of the sectors within a BTS  Automatically replaces a faulty BCCH TRX kris.sujatmoko@gmail.com
  154. 154. GSM-GPRS Operation Adjacency Parameters
  155. 155. 155 Adjacency Parameters kris.sujatmoko@gmail.com
  156. 156. 156 Adjacency Parameters (2)  Used to control dedicated mode MS for HO purpose  These parameters play only the support role to HO or any other optional features kris.sujatmoko@gmail.com
  157. 157. 157 Adjacency Parameters (3) kris.sujatmoko@gmail.com
  158. 158. 158 Adjacency Parameters (4)  hoTargetArea:  indicates whether the adjacent cell is an extended range cell or a normal cell  If the adjacent cell is an extended cell, it determines which TRX (extended or normal) of the adjacent cell from where the BSC will allocates a TCH during an intra-BSC HO attempt  0 = Normal cell  1 = Extended range cell, a TCH is allocated from a normal TRX  2 = Extended range cell, a TCH is allocated from an extended range TRX.  3 = Extended range cell, a TCH is allocated from a TRX whose type (extended range or normal range) is the same as the type of the serving TRX. kris.sujatmoko@gmail.com
  159. 159. 159 Dualband Parameters  multibandCell  define whether adjacent cells with a BCCH allocated from a different frequency band than the serving cell BCCH are taken into account in handovers and in idle mode cell selection or reselection  earlySendingIndication  accept or forbid the early sending of the MS Classmark 3 message in call setup phase to the network  multiBandCellReporting  define the number of adjacent cells from the other frequency band that the MS will report in the RX level report kris.sujatmoko@gmail.com
  160. 160. GSM-GPRS Operation MS Mobility Management
  161. 161. 161 Mobility Management  Dual-band MS:  Idle mode  Dedicated mode  Objectives:  To manage traffic more efficiently  To increase call setup success rate  Strategies:  Accommodate both single and dualband MS in both dedicated and idle mode with existing network configuration and traffic volume  How to design?  Using existing BSS parameters  Dualband parameters kris.sujatmoko@gmail.com
  162. 162. 162 MM (2) – Idle Mode kris.sujatmoko@gmail.com
  163. 163. 163 MM (3) – Case Study  Case study as follows:  Network access preference:  GSM900 layer  DCS1800 layer  Justification?  GSM900 is a contiguous coverage layer  DCS1800 is a capacity relief layer  How to design?  Idle Mode:  Make DCS1800 layer less attractive by setting negative offset to C2  Only singleband (1800) MS is allowed to access the DCS1800 layer  Dualband and singleband(900) access GSM900 layer kris.sujatmoko@gmail.com
  164. 164. 164 MM (4) – Dedicated Mode kris.sujatmoko@gmail.com
  165. 165. 165 MM (5) – Case Study  Case study as follows:…continue  Dedicated Mode:  Depending on the cell traffic and cell configuration  HO preference:  G900 to D1800 (negative power budget margin)  D1800 to D1800 (normal power budget with higher priority)  G900 to G900 (normal power budget with lower priority)  D1800 to G900 (large positive power budget margin) kris.sujatmoko@gmail.com
  166. 166. 166 MM (6)  Case study as follows:…continue  The good and the bad of this strategy  Advantage:  Simple parameter modification (only C2 required change for idle mode MM)  DCS1800 traffic load can be managed based on cell-by- cell basis  Disadvantage:  GSM900 may suffer call setup blocking (both dualband and G900 MS access network directly)  High HO rate kris.sujatmoko@gmail.com
  167. 167. 167 MM (7) – Idle Mode kris.sujatmoko@gmail.com
  168. 168. 168 MM (8) – Dedicated Mode kris.sujatmoko@gmail.com
  169. 169. 169 Dual Band Network Operation  Idle Mode For Dualband Mobile Management kris.sujatmoko@gmail.com
  170. 170. 170 MM (9)  A dual-band multi-layer network design  Design criteria:  GSM band layer consideration  Macro-micro layer consideration  Idle mode preference:  GSM900->DCS900  Micro followed by macro for slow moving  Macro followed by micro for fast moving  Dedicated mode preference:  DCS1800->GSM900 kris.sujatmoko@gmail.com
  171. 171. 171 MM (10)  A dual-band multi-layer network design…continue  Network topology consideration  Neighbour relationships  Adjacency parameters set kris.sujatmoko@gmail.com
  172. 172. GSM-GPRS Operation BSC Parameters
  173. 173. 173 BSC Parameters kris.sujatmoko@gmail.com
  174. 174. 174 BSC Parameters (2)  Cell Definition For Multilayer Network kris.sujatmoko@gmail.com
  175. 175. 175 BSC Parameters (3) – Cell Definition  How to set?  MsTxPwrMaxCell(n) >= gsmMacrocellThreshold– adjacent cell type is macrocell  MsTxPwrMaxCell(n) <= gsmMicrocellThreshold– adjacent cell type is microcell  BSC Parameters:  gsmMicrocellThreshold = 33 dBm  gsmMacrocellThreshold = 35 dBm  Cell Parameter:  msTxPwrMax(n) = 33 dBm kris.sujatmoko@gmail.com
  176. 176. 176 BSC Parameters (4) – Cell Definition  What these values mean?  (MsTxPwrMax(n) = 33dBm) <= (gsmMicrocellThreshold = 33dBm)  the adjacent cell type is microcell kris.sujatmoko@gmail.com
  177. 177. 177 BSC Parameters (5) – MSC HO kris.sujatmoko@gmail.com
  178. 178. 178 BSC Parameters (6) – MSC HO  How to set disableIntHo?  Set to YES – not all HO is controlled by MSC  Only inter-BSC HO requires MSC  Intra-BSC HO will not require MSC  To reduce MSC load  Set to NO - all HO is controlled by MSC kris.sujatmoko@gmail.com
  179. 179. 179 BSC Parameters (7) – MSC HO  How to set genHandoverRequestMessage?  Typical values is 3  3 preferred cells are included in the HANDOVER REQUIRED message  The message is sent from BSC to MSC  Only for inter-BSC HO scenario kris.sujatmoko@gmail.com
  180. 180. 180 BSC Parameters (8) – Directed Retry  How to set disableExtDr?  Set to YES – external directed retry HO will not be allowed  Set to NO – external directed retry HO will be allowed when it is necessary  Inter-BSC directed retry HO will take place for cells at the BSC boundary kris.sujatmoko@gmail.com
  181. 181. 181 BSC Parameters (9) – Handover Type  How to set hoPreferenceOrderInterfDL?  Set to inter – intercell HO is preferred when HO is due to DL interference  Set to intra - intracell HO is preferred when HO is due to DL interference kris.sujatmoko@gmail.com
  182. 182. 182 BSC Parameters (10) – Handover Type  How to set msDistanceBehaviour?  Action taken after timing advance has exceeded the threshold  Value = 255 – no channel release, only HO attempts  Value = 0 – release channel immediately, no HO attempts  Value = 10  HO attempt within 10 seconds after the timing advance has been exceeded  Channel will be released if HO does not succeed during the 10 seconds window period kris.sujatmoko@gmail.com
  183. 183. 183 BSC Parameters (11) – Handover Type  How to set rxLevBalance?  This parameter is used for the purpose of uplink interference level calculation  Typical value = 6 dB kris.sujatmoko@gmail.com
  184. 184. 184 BSC Parameters (12) – MS Speed Detection  How to set msSpeedC11?  This parameter for MS speed related HO  If you decide maximum MS speed for slow moving traffic is 20 km/h  The value should be set to 10  Any MS speed exceeds the 20 km/h threshold will be considered fast moving traffic kris.sujatmoko@gmail.com
  185. 185. 185 BSC Parameters (13) – Advanced Multilayer Handling kris.sujatmoko@gmail.com
  186. 186. 186 BSC Parameters (14) Advanced Multilayer Handling  How to set amhUpperLoadThreshold?  This parameter defines the maximum cell traffic load  When the the cell traffic load exceeds the threshold, intra-BSC traffic reason HO will occur  Example: amhUpperLoadThreshold = 70%  If the cell traffic load is 75%, Traffic Reason HO will be initiated kris.sujatmoko@gmail.com
  187. 187. 187 BSC Parameters (15) Advanced Multilayer Handling  How to set amhLowerLoadThreshold?  This parameter defines the minimum cell traffic load  If the traffic load of the serving cell does not exceed the amhLowerLoadThreshold, the IUO handover or the Direct Access to super- reuse TRX are not allowed kris.sujatmoko@gmail.com
  188. 188. 188 BSC Parameters (16) Advanced Multilayer Handling  How to set amhMaxLoadOfTargetCell?  This parameter defines the maximum adjacent cell traffic load  If the adjacent cell traffic load is below this threshold, the cell can be the target for Traffic Reason HO  Example: amhMaxLoadOfTargetCell = 80%  If the adjacent cell traffic load is 60%, this cell can be the target cell for Traffic Reason HO kris.sujatmoko@gmail.com
  189. 189. 189 BSC Parameters (17) Advanced Multilayer Handling  How to set amhTrhoGuardTime?  This parameter defines the guard time before Handover back to original cell is allowed  If set to 10 seconds  BSC-controlled or MSC-controlled Traffic Reason HO occurs  During this 10 seconds period, HO back to the original cell is NOT allowed  Handover back to original cell can only be allowed after the 10 seconds period expires kris.sujatmoko@gmail.com
  190. 190. 190 BSC Parameters (18) – Dynamic Hotspot  What these parameters mean?  badQualLimit:  define the limit for bad signal quality in term of proportion of bad samples in all samples in signal quality measurement.  goodQualLimit:  define the limit for good signal quality.  The value of the parameter has to be equal to or smaller than the value of the signal quality limit 2 (SQL2) parameter. kris.sujatmoko@gmail.com
  191. 191. 191 BSC Parameters (19) – Dynamic Hotspot  sigQualLimit1:  define the lower limit for adequate signal quality in adjacent cells.  the value of the parameter has to be equal to or smaller than the value of the bad quality limit (BQL) parameter.  sigQualLimit2:  define the upper limit for adequate signal quality in adjacent cells.  The value of the parameter has to be equal to or smaller than the value of the signal quality limit 1 (SQL1) parameter.  GQL<=SQL2<=SQL1<=BQL kris.sujatmoko@gmail.com
  192. 192. 192 BSC Parameters (20) – Dynamic Hotspot  tchProbability1: define the probability of TCH allocation when signal quality in the adjacent cell, x signal quality limit 1 (SQL1) <= x < bad quality limit (BQL) .  tchProbability2: define the probability of TCH allocation when signal quality in the adjacent cell, y signal quality limit 2 (SQL2) <= y < signal quality limit 1 (SQL1) >= TCH probability 1 (TCP1) parameter.  tchProbability3: define the probability of TCH allocation when signal quality in the adjacent cell, z good quality limit (GQL) <= z < signal quality limit 2 (SQL2). >= TCH probability 2 (TCP2) parameter. kris.sujatmoko@gmail.com
  193. 193. 193 BSC Parameters (21) – Dynamic Hotspot  Operator defined probability table  The probability is set by operator kris.sujatmoko@gmail.com
  194. 194. 194 BSC Parameters (22) – Dynamic Hotspot Example kris.sujatmoko@gmail.com
  195. 195. 195 BSC Parameters (23) – Dynamic Hotspot Example  The probability to allocate TCH in cell A is 51%  The probability to allocate TCH in cell B is 80%  The average probability is 51%*80% = 40% < fixed reference = 50%  Reject resource request kris.sujatmoko@gmail.com
  196. 196. GSM-GPRS Operation End of Section 5 BSS Parameter

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