|
KPI |
Target |
FORMULAE - ERICSSON |
|
Random Access Success Rate % |
>=98 |
100 * CNROCNT / (CNROCNT + RAACCFA) |
|
SDCCH Blocking % |
<=0.5 |
100 * CCONGS / CCALLS |
|
SDCCH Drop % |
<=1.2 |
100 * (CNDROP - CNRELCONG) /
CMESTAB |
|
TCH Blocking % |
<=1 |
100 * (CNRELCONG + TFNRELCONG +
THNRELCONG) / TASSALL |
|
TCH Time Congestion/Cell |
<=50 sec |
Cells with Full Rate only: 100 *
TFTCONGS / (PERLEN*60) Cells with Half Rate: 100 * THTCONGS / (PERLEN*60) |
|
TCH Assignment Success Rate % |
>=97 |
100 * TCASSALL / TASSALL |
|
TCH Drop % |
<=2 |
100 * TNDROP / TCASSALL |
|
Handover Success Rate % |
>=95 |
100 * HOVERSUC / HOVERCNT |
|
Avg SDCCH Congestion/cell |
<=50 sec |
100 * CTCONGS / (PERLEN*60) |
|
Avg TCH Congestion/cell |
<=200 sec |
Cells with Full Rate only: 100 *
TFTCONGS / (PERLEN*60) Cells with Half Rate: 100 * THTCONGS / (PERLEN*60) |
|
Network Availability (Radio)% |
>=99.90 |
100 * (No of days * 24 * 60 * Total
No of Cells – Summation of Downtime in minutes of Cells) / (No of days *
24 * 60 * Total No of Cells) |
|
SDCCH Congestion <=30 sec |
>90 |
100 * CTCONGS / (PERLEN*60) |
|
% of cells having SQI samples
between 16-30 >90% |
>90 |
90% of cells having percentage of
Good samples>90% |
|
Peak Processor Load (MSCs/BSCs) % |
<=80 |
ACCLOAD/NSCAN (These counters are
available in object type LOAS) |
|
Switch BHCA Utilization (during
Switch NBH) |
<=80 |
100*( BHCA/SwitchBHCA Capacity) |
|
Paging Success Rate (24 hrs) % |
>=90 |
100 * (NLAPAG1RESUCC + NLAPAG2RESUCC)
/ NLAPAG1TOT |
|
Location Update Success Rate (24
hrs) % |
>=95 |
100 * NLALOCSUCC / NLALOCTOT |
|
Successful Call Rate (24 Hrs) % |
>=95 |
(NBANS + NABEFA1 + NABEFA2 +
NCAWNOA + NTOBEFA + NBOUT + NBBUSY) / NCALLS |
|
Network Availability (Switch/IN)% |
>99.99 |
100 * (No of days * 24 * 60 * Total
No of Nodes – Summation of Downtime in minutes of Nodes) / (No of days *
24 * 60 * Total No of Nodes) |
|
Core Network Availability % |
>99.99 |
100 * (No of days * 24 * 60 * Total
No of Nodes – Summation of Downtime in minutes of Nodes) / (No of days *
24 * 60 * Total No of Nodes) |
|
Attach Success Rate excluding
Unregistered Subs. % |
>=99 |
100 * [1 - ((gprsMmSgsnUnsuccAttReq
- gprsMmSgsnUnsuccAttReqCC7/8/14) / gprsMmSgsnAttReq)] |
|
PDP context activation success rate
(Only NW Cause codes) % |
>=99 |
100 * gprsSmSgsnSuccActivations /
(gprsSmSgsnSuccActivations + gprsSmSgsnUnsuccActivations) |
|
Round trip time |
<=700 ms |
Ping either a DNS server or an
external Internet server by the MS PING SIZE - 32BYTE |
|
Average UL throughput per TBF |
>=20 kbps |
ULBGEGTHR / ULBGEGDATA |
|
Average DL throughput per TBF |
>=45 kbps |
DLBGEGTHR / DLBGEGDATA |
Ericsson KPI Formula
Timer Parameter
TIMER PARAMETER
T3103 - Handover command
T100 - RLT is the timer for holding of call if SACCH multiframe is not decoded than RLT
timer is start and if RLT is reach is zero than call will disconnected.
Default value of this timer is 28.
T3105 - Time between repetitions of physical information to MS. Will be repeated NY1 times.
Recommend Value 8 (1 = 10MiliSecond)
T3124 - Handover access
T3212 - Location Update parameter
T3107 - Assignment command
T3113 - This timer is start after PAGING REQUEST and stop before paging response.
T3260 - The timer is started when AUTHENTICATION REQUEST is sent from MSC.
The timer is stopped when AUTHENTICATION RESPONSE is received in MSC.
T3101 - The BSS allocates a SDCCH, if available, and sends a IMMEDIATE ASSIGNMENT message on the downlink. This message contains the details of allocated SDCCH, TSC, and TA etc. As soon as the BSS allocates and sends message on the AGCH, it starts a timer T3101. This timer is set in millisecs.
T3110 - On the receipt of the channel release, the MS starts internal timer T3110 and disconnects the main signalling link.
T3111 - When T3111 has expired all RF links are terminated.
AMR (Adaptive Multi Rate)
Adaptive Multi Rate (AMR) is a new speech and channel codec for both half rate and full rate channels. By adapting the codec rate to the radio conditions the speech quality is enhanced. At low C/I, a large amount of channel coding is applied and less speech coding. When the C/I increase the speech coding is increased and the channel coding is decreased.
Both the BTS (uplink) and the MS (downlink) continuously measures the radio quality (C/I) and based on these measurements the codec rate is changed. AMR requires support in all network nodes, i.e. MSC, BSC, BTS and MS and AMR is only supported in cells where all TRUs are AMR capable.
AMR makes it possible to change codec rate during a call. There are 8 different codec rates available in the AMR transcoder: 12.2kbps, 10.2kbps, 7.95kbps, 7.40kbps, 6.70kbps, 5.90kbps, 5.15kbps, and 4.75kbps
According to the standard, 12.2 kbps and 10.2 kbps can only be used in FR channels and the other six can be used in both FR and HR channels, on the air interface.
Frequency Hopping
Frequency Hopping:
Frequency Hopping is mechanism in which the system changes the frequency (uplink and downlink) during transmission at regular intervals. It allows the RF channel used for signaling channel (SDCCH) timeslot or traffic channel (TCH) timeslots, to change frequency every TDMA frame (4.615 ms). The frequency is changed on a per burst basis, which means that all the bits in a burst are transmitted in the same frequency. In 1Sec= 217Hopes
Advantages of Frequency Hopping: Frequency Diversity, Interference Averaging, Increase capacity
There are two types of hopping 1 Base Band FH (BBH) 2 Synthesizer FH (SFH).
1. Base Band Frequency Hopping: In baseband hopping, each transmitter is assigned with a fixed frequency. At transmission, all bursts, irrespective of which connection, are routed to the appropriate transmitter of the proper frequency. The advantage with this mode is that narrow-band tunable filter combiners can be used.
2. Synthesizer Frequency Hopping (SFH). Synthesizer hopping means that one transmitter handles all bursts that belong to a specific connection. The bursts are sent "straight on forward" and not routed by the bus. In contrast to baseband hopping, the transmitter tunes to the correct frequency at the transmission of each burst the advantage of this mode is that the number of frequencies that can be used for hopping is not dependent on the number of transmitters. It is possible to hop over a lot of frequencies even if only a few transceivers are installed. A disadvantage with synthesizer hopping is that wide-band hybrid combiners have to be used. This type of combiner has approximately 3 dB loss making more than two combiners in cascade impractical.
Frequency Hopping Parameters
Mobile Allocation (MA): Set of frequencies the mobile is allowed to hop over. Maximum of 63 frequencies can be defined in the MA list.
Hopping Sequence Number (HSN): Determines the hopping order used in the cell. It is possible to assign 64 different HSNs. Setting HSN = 0 provides cyclic hopping sequence and HSN = 1 to 63 provide various pseudo-random hopping sequences.
Mobile Allocation Index Offset (MAIO): Determines inside the hopping sequence, which frequency the mobile starts do transmit on. The value of MAIO ranges between 0 to (N-1) where N is the number of frequencies defined in the MA list. Presently MAIO is set on per carrier basis.
Basic Parameter of WCDMA
Basic Parameters of WCDMA
Frequency Band : 2100 MHz
1920-1980MHz (UL) &2110-2170 MHz (DL)
Duplex Space : 190 MHz
Channel bandwidth : 5 MHz
Coding Spacing : 200 KHz (RASTER)
UARFCN Range : 10562-10838 (Total ARFCN – 276)
Duplex mode : FDD and TDD
Downlink RF channel structure : Direct spread
Chip rate& Chips : 3.84 Mcps& It is pulse of spreading spectrum n
It’s in rectangular shape of +1 & -1
Frame length : 10 ms (38400 chips) = 15Slots, & 1slot = 2650chips
Superframe : A Superframe has a duration of 720ms and consists
Of 72 radio frames. The super frame boundaries are
Defined by the System Frame Number (SFN)
Spreading modulation : Balanced QPSK (downlink)
Dual-channel QPSK (uplink)
Complex spreading circuit
Data modulation : QPSK (downlink) & BPSK (uplink)
Channel coding : Convolution (Voice) and turbo (data) codes
Coherent detection : User dedicated time multiplexed pilot (DL and UL),
Common pilot in the downlink
Channel multiplexing in downlink : Data and control channels time multiplexed
Channel multiplexing in uplink : Control and pilot channel time multiplexed
I&Q multiplexing for data and control channel
Spreading factors : 4–256 (uplink), 4–512 (uplink)
Power control : Open and fast closed loop (1.6 kHz)
Power control period : 1500Hz
Power control step size : 0.5, 1, 1.5 and 2db
Power control range
Handover : Soft HO, softer HO, Inter frequency and IRAT HO
2G GSM Network Quality Index ( NQI )
Network_Quality_Index_(NQI)
| ||
Radio_NBH_KPI
| ||
1
|
SDCCH_Completion_Rate_(NBH)_NQI
|
Max:100,Min:99,Wtg:5
|
2
|
TCH_Completion_Rate_(NBH)_NQI
|
Max:100,Min:98.5,Wtg:5
|
3
|
Handover_Success_Rate_NQI
|
Max:100,Min:97,Wtg:4
|
4
|
SDCCH_Assignment_Success_NQI
|
Max:100,Min:99.5,Wtg:4.5
|
5
|
TCH_Assignment_Success_NQI
|
Max:100,Min:98,Wtg:4.5
|
6
|
TCH_Congestion_NQI
|
Max:0,Min:2,Wtg:3
|
7
|
RX_Quality_DL(0-5)_NQI
|
Max:100,Min:97,Wtg:3
|
8
|
Radio_Network_Availability_(24_hours)_NQI
|
Max:100,Min:99.95,Wtg:5
|
9
|
ErlangMinutesperDrop(NBH)@NQI
|
Max:360,Min:120,Wtg:3
|
Cell_BBH_KPI
| ||
10
|
SDCCH_Completion_Rate_(BBH)>=98%_NQI
|
Max:100,Min:95,Wtg:8
|
11
|
TCH_Completion_Rate_(BBH)>=98%_NQI
|
Max:100,Min:95,Wtg:8
|
12
|
Handover_Success_Rate_(BBH)>=95%_NQI
|
Max:100,Min:95,Wtg:3
|
13
|
SDCCH_Assignment_Success_(BBH)>=99%_NQI
|
Max:100,Min:95,Wtg:5.5
|
14
|
TCH_Assignment_Success_(BBH)>=97%_NQI
|
Max:100,Min:95,Wtg:5.5
|
15
|
TCH_Congestion_(BBH)<2%_NQI
|
Max:100,Min:95,Wtg:3
|
16
|
RX_Quality_DL(0-5)_(BBH)>=96%_NQI
|
Max:100,Min:95,Wtg:3
|
17
|
Random_Access_rate>=95%_NQI
|
Max:100,Min:95,Wtg:3
|
Data_KPI
| ||
22
|
EDGE_DL_Average_Thruput_per_TBF_(DBH)_NQI
|
Max:110,Min:100,Wtg:2
|
23
|
GPRS_DL_Average_Thruput_per_TBF_(DBH)_NQI
|
Max:36,Min:27,Wtg:2
|
24
|
TBF_Success_Rate_(DBH)_NQI
|
Max:100,Min:93,Wtg:2
|
25
|
DL_Multislot_Assignment_Success_(DBH)_NQI
|
Max:100,Min:95,Wtg:2
|
Total NQI
| ||
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