Hard Blocking & Soft Blocking:In Data Services PDTCH access failure can be separated in two types. 1. Hard blocking 2. Soft blocking Hard Blocking. Hard blocking describes the situation when NO Radio Resources are assigned after the GPRS/EDGE service request in Data Services and access to Data services is denied. For instance, if we consider a case when a user requests resource for Data Service access and no resources at all are assigned, this is characterized as Hard Blocking. Soft Blocking. Soft blocking considered the scenarios that allocated channel numbers doesn’t meet the MS multi-timeslot capability after data service has established i.e. Soft blocking where users are assigned a “PORTION” of the resources they request.
Hard Blocking Formula & Counter:Hard Blocking UL (%) = (([A9203]+[A9003])/([A9001]+[A9201]))*{100} where, A9203=Number of Failed Uplink EGPRS TBF Establishments due to No Channel A9003=Number of Failed Uplink GPRS TBF Establishments due to No Channel A9001=Number of Uplink GPRS TBF Establishment Attempts A9201=Number of Uplink EGPRS TBF Establishment Attempts
Similarly, Hard Blocking DL (%) = (([A9103]+[A9303])/([A9101]+[A9301]))*{100} where, A9103=Number of Failed Downlink GPRS TBF Establishments due to No Channel A9303=Number of Failed Downlink EGPRS TBF Establishments due to No Channel A9101=Number of Downlink GPRS TBF Establishment Attempts A9301=Number of Downlink EGPRS TBF Establishment Attempts
Checks for Removal of Hard Blocking:-
1. Find out the sectors with Hard Blocking greater than 2% (cells coming in any three days out of Five Working Days). 2. HB > 2%, Utilization > 80%, TRX > 8 :- Capacity Sites Required/IBCA 3. HB > 2%, Utilization > 80%, TRX < 8 :- TRX Addition to be done 4. HB > 2%, Utilization < 80%, TRX < 8 :- TRX Addition to be done 5. HB > 2%, Utilization < 80%, TRX > 8 TCH Blocking < 0.0 :- Static PDCH Addition to be done and TCH Blocking need to moniter. 6. HB > 2%, Utilization < 60%, TRX > 8, TCH Blocking < 0.25 :- Static PDCH Addition to be done.
NOTE: Pls keep Static TS addition as a last option.
Soft Blocking Formula & Counter:Soft Blocking DL (%) = ({1}-(([DL tsl allocated Soft Blocking_NUM 1]+[DL tsl allocated Soft Blocking_NUM 2])/([DL tsl allocated Soft Blocking_DENOM 1]+[DL tsl allocated Soft Blocking_DENOM 2])))*{100}
DL tsl allocated Soft Blocking_ NUM 1
([S9314:Times of Downlink Timeslot Occupancy 1/5]*{1}+[S9315:Times of Downlink Timeslot Occupancy 2/5]*{2}+[S9316:Times of Downlink Timeslot Occupancy 3/5]*{3}+[S9317:Times of Downlink Timeslot Occupancy 4/5]*{4}+[S9318:Times of Downlink Timeslot Occupancy 5/5]*{5}+[S9319:Times of Downlink Timeslot Occupancy 1/4]*{1}+[S9320:Times of Downlink Timeslot Occupancy 2/4]*{2}+[S9321:Times of Downlink Timeslot Occupancy 3/4]*{3}+[S9322:Times of Downlink Timeslot Occupancy 4/4]*{4})
DL tsl allocated Soft Blocking_ NUM 2
([S9323:Times of Downlink Timeslot Occupancy 1/3]*{1}+[S9324:Times of Downlink Timeslot Occupancy 2/3]*{2}+[S9325:Times of Downlink Timeslot Occupancy 3/3]*{3}+[S9326:Times of Downlink Timeslot Occupancy 1/2]*{1}+[S9327:Times of Downlink Timeslot Occupancy 2/2]*{2}+[S9328:Times of Downlink Timeslot Occupancy 1/1]*{1})
DL tsl allocated Soft Blocking_D ENOM 1
([S9314:Times of Downlink Timeslot Occupancy 1/5]*{5}+[S9315:Times of Downlink Timeslot Occupancy 2/5]*{5}+[S9316:Times of Downlink Timeslot Occupancy 3/5]*{5}+[S9317:Times of Downlink Timeslot Occupancy 4/5]*{5}+[S9318:Times of Downlink Timeslot Occupancy 5/5]*{5}+[S9319:Times of Downlink Timeslot Occupancy 1/4]*{4}+[S9320:Times of Downlink Timeslot Occupancy 2/4]*{4}+[S9321:Times of Downlink Timeslot Occupancy 3/4]*{4}+[S9322:Times of Downlink Timeslot Occupancy 4/4]*{4})
DL tsl allocated Soft Blocking_D ENOM 2
([S9323:Times of Downlink Timeslot Occupancy 1/3]*{3}+[S9324:Times of Downlink Timeslot Occupancy 2/3]*{3}+[S9325:Times of Downlink Timeslot Occupancy 3/3]*{3}+[S9326:Times of Downlink Timeslot Occupancy 1/2]*{2}+[S9327:Times of Downlink Timeslot Occupancy 2/2]*{2}+[S9328:Times of Downlink Timeslot Occupancy 1/1]*{1})
Checks for Removal of Soft Blocking:-
1. Find out the sectors with Soft Blocking greater than 20% (cells coming in any three out of Five Working Days). 2. SB > 20%, Utilization > 80%, TRX > 8 :- Capacity Sites Required/IBCA. 3. SB > 20%, Utilization > 80%, TRX < 8 :- TRX Addition to be done 4. SB > 20%, Utilization < 80%, TRX < 8 :- TRX Addition to be done 5. SB > 20%, Utilization < 80%, TRX > 8 TCH Blocking < 0.0:- Static PDCH Addition to be done. 6. SB > 20%, Utilization < 60%, TRX > 8, TCH Blocking < 0.25:- Static PDCH Addition to be done.
NOTE: Pls keep Static TS addition as a last option.
Abis Congestion Calculation:Below are counters we use to monitor the Abis status for PS service. They are captured in Report called “EDAP Report”. This is Cell Level D-BBH Report.
R9101:Number of Application Attempts of Abis Timeslot(times) R9102:Number of Successful Application Attempts of Abis Timeslot(times) R9109:Number of Unsuccessful Application Attempts of Abis Timeslot Because of no Idle Timeslot(times)
EDAP Congestion is counted as below, = 100* (R9101 – R9102) / (R9101)
Event Triggering (R9101, R9102, R9109): When the Abis interface uses the TDM connection mode, if the PDCH coding scheme is adjusted, the idle Abis timeslot application or release may be initiated to support the adjustment of the PDCH coding scheme. Each time the PDCH requests an Abis timeslot for the adjustment of the PDCH coding scheme, the counter is incremented by one.
EDAP configuration (Idle TS):-
Maximum no of Idle TS we can use based on no. of TRXs is as below
But this EDAP Configuration can’t be appropriate in present MS scenarios.
TATA Requirement for Data Services on UM Interface are 2 Static TS & 100% Switchable TS. Also it is requested to have EDAP Congestion very Low.
With 100% switchable TS on UM, EDAP Congestion Level will be very High as whenever system allows to convert TCH to PDTCH (depending on CS Traffic) it will be done on UM but failed on Abis part as ABIS Resources are always limited (DSP Capacity/Max Idle TS Definition).
Checks for Removal of Abis Congestion:-
1. Find out the sectors with EDAP Failure (Unsuccessful Application Attempts of Abis Timeslot Because of no Idle TS/ Application Attempts of Abis TS) greater than 30% and Application Attempts of Abis TS is above 100 (sites coming in Five continue Working Days). 2. Check for IDLE TS configuration. Add maximum IDLE TS in existing E1. 3. Mapping must be proper of idle TS. 4. Check Data download (MB) of a site before adding second E1, Download of DATA BBH should be greater than 100Mb. 5. Additional E1 to be added.
TCH to PDTCH Conversion Details:
R9341: TCH_TO_PDTCH_ATMPT:-
Description This measurement provides the number of attempted conversions from the TCH to the PDCH in a cell in a granularity period.
Unit: None.
Measurement Point In a granularity period, the counter is incremented by one every time a TCH attempts to convert into a PDCH.
R9342: TCH_TO_PDTCH_SUCC
Description This measurement provides the number of successful conversions from the TCH to the PDCH in a cell in a granularity period.
Unit: None.
Measurement Point In a granularity period, the counter is incremented by one every time a TCH is successfully converted into a PDCH.
TCH to PDTCH Conversion Logic:-
Convert TCH to PDTCH if TCH (Switchable TS) are available for Data Services. This is done after verifying 1 Vacant TCH TS is available.
Idle TS (Abis) are available for TCH to PDTCH conversion.
PDTCH on carrier is less than Maximum PDTCH numbers of carrier
% PDTCH on cell level is less than Maximum Ratio Threshold of PDCHs in a Cell (%).
Busy Dynamic PDTCH Reclaim:-
R9344: RECLAIM_DYN_LOAD_PDCH:-
Description
This measurement provides the number of times the BSC converts the busy dynamic PDCH to the TCH in a cell in a granularity period. It indicates the situation where the CS service preempts the PS service in a granularity period.
Dynamic PDCH reclaim: Convert condition Dynamic PDCH will be preempted by CS service when no CS idle channel left.
