PRFAIL2013 - 08 - 28

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PRFAIL Counters

Random Access and RACH

Random Access Channel (RACH) is transmitted on UL

When a MS is paged it replies on RACH requesting signaling channel (SDCCH)

RACH is also used for MS originating call

PRFAIL – percentage random access failures,

RAACCFA – failed random accessCNROCNT – all accepted random accessPDRAC – packet data random access

PRFAIL FORMULA

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What causes poor Random Access?

Random Access & Accessibility

PRFAIL – percentage random access failures, forms part of broader Accessibility KPI’s, contribute 5.32% to GSM Primary HI

RAACCFA – failed random access must be minimized

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What causes poor Random Access?

co BCCH/BSIC clashes – need to minimize the use of co BCCH/BSIC across the same BSC

Poor BCCH plan – an MS originating call or MS response to paging uses timeslot on BCCH frequency, high level of interference co/adj on BCCH can poor Random Access success rate

Poor Coverage or Overshooters – check cells with high drops due to UL/DL signal strength, confirm TA using MRR or may use Arieso to check cell footprint, improve dominance, downtilt/uptilt

Hardware alarms, high VSWR

Idle Mode Parameters – AccMin & CRO

One can tune AccMin and CRO for an overshooting cell with high RAACCFA, but this is not good solution, DOWNTILT as a permanent solution

MAXTA and TX ParametersCheck correct settings of MAXTA and TX parameters (RSLBP)

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SanRan Week-34 Worst PRFAIL

CELL SITENAME NE PLANNER PRFAIL RAACCFA PRFAIL_HI PRIMARY_HI ERLANG

2087A Heyns Films RBBSC2 TRENADE GOUNDER 0.81 10,614 58.34 36.86 313.37

433A Andrew Forssman RBBSC2 TRENADE GOUNDER 0.74 9,631 60.69 78.97 1,203.05

3041B 393 Aureole Road NLBSC2 ABEGAIL MABUNDA 5.29 41,866 0.74 72.06 307.78

2455C Vorna Valley Spar RBBSC2 TRENADE GOUNDER 1.05 7,562 45.91 49.96 495.73

7495A Elshama Guest House GEBSC2 TRENADE GOUNDER 2.12 11,301 17.41 43.89 142.57

2162B Villa Seville RBBSC3 TRENADE GOUNDER 0.24 4,053 88.8 51.01 633.34

2537C Standard Bank Riverclub RBBSC2 TRENADE GOUNDER 0.85 3,626 59.18 58.55 235.74

1410B Hillfox Trade Centre RBBSC3 ABEGAIL MABUNDA 0.44 3,659 78.23 90.92 1,106.03

2087C Heyns Films RBBSC2 TRENADE GOUNDER 0.14 3,226 93.72 73.9 728.76

4895B Sunninghill CC RBBSC2 TRENADE GOUNDER 2.41 8,109 14.73 89.52 295.37

9142C Boundary Park Eaton NLBSC2 ABEGAIL MABUNDA 0.21 3,370 90.22 32.11 141.96

2147A Schoongezight Bergbron NLBSC4 ABEGAIL MABUNDA 0.54 2,566 75.59 47.38 84.41

7782B Park Centre RBBSC1 SIMON MAKGOPA 0.73 2,019 66.07 84.62 147.48

7491B Republic Dam CC RBBSC3 ABEGAIL MABUNDA 0.66 2,206 65.74 94.9 299.59

1001C Randpark Ridge S/Centre RBBSC3 ABEGAIL MABUNDA 0.56 2,318 74 83.29 170.92

7497C Megawatt Park Rooftop RBBSC2 TRENADE GOUNDER 2.01 4,747 21.44 91.18 88.26

6885A Wendywood High VC RBBSC2 TRENADE GOUNDER 2.8 4,403 8.11 91.97 51.02

628C Mainline RBBSC3 ABEGAIL MABUNDA 0.81 985 61.6 74.43 36.94

2328A Esher Place RBBSC1 SIMON MAKGOPA 0.67 1,400 61.44 72.2 37.11

1145C Pine Park Centre RBBSC1 ABEGAIL MABUNDA 3.01 3,966 6.88 61.1 42.69

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T2087A Arieso RxLev footprint

T2087A – overshooting ~ 5km away, DOWNTILT

Tune CRO from 0dB to -8dBi.e. CRO changed from 0 to 4 and PT from 0 to 31

@11:30AM 28-Aug-2013

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