TEMS GSM PARAMETERS On completion of the module one should be clear about the parameters required during drive test what does it means and how important they are. Parameters regarding in windows like:
Current Channel Radio Parameters Serving + Neighbors EGPRS Line Chart GSM Data Timeslots
GSM CURRENT CHANNEL Dinec Global Resources Limited (DGRL)
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Time: It is system time of computer in text format: HH:MM:SS.mm, where mm = decimal seconds. Cell name: It displays the name of the sector which is
serving according to the cell-file that is loaded in TEMS. CGI : It stands for the Cell Global Identity which is unique for every sector of the site. It consists of MCC, MNC, LAC, CI. MCC: Mobile Country Code 0 – 999 (e.g. 621 in Nigeria), MNC: Mobile Network Code 0 – 99 (e.g. 50 for Globacom in Nigeria) LAC : Location Area Code 0 -65535 (e.g. 30403 in Rivers State) CI: Cell Identity 0 – 65535 (e.g. 14977) Cell GPRS Support: Tells sector is having GPRS or not. Values are Yes or No. Band: It tells in which Freq. Band mobile is operating e.g. GSM 900/ 1800. BCCH ARFCN: It tells by which BCCH is the mobile station getting served. Dinec Global Resources Limited (DGRL)
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TCH ARFCN: On which Traffic Freq. call is going on. BSIC (Base Station Identity Code): It is combination of Network Color Code (NCC) (0 - 7) & Base Station Color Code (BCC) (0 – 7). e.g. 70. It is decoded by mobile on every Synchronization Channel Message. Mode: It is shows in which state is mobile operating, No Service, Idle, Dedicated, Limited Service, Scan, Packet & Packet Idle modes. Time slot: On which time slot of current TCH call is going on. Viz. time slot no. of TRX. Channel Type: Type of channel mobile is getting now. Like BCCH / SDCCH/8 + SACCH/C8 or CBCH / TCH/F+FACCH/F +SACCH/F. Channel Mode: Shows mode of coding like Speech Full Rate of Half Rate. Speech Codec: It shows FR for Full Rate, HR for Half Rate & EFR for Enhanced Full Rate. Ciphering Algorithm: It shows ciphering algorithm used by the system to protect data for privacy. E.g. Cipher by A5/2. Sub Channel Number: It is displayed at a time when mobile is on dedicated mode at time of call setup when it is getting SDCCH at that time it shows which SDCCH it is getting out of 8 available. E.g. 0. Hopping Channel: It shows that current sector is having hopping feature or not. Values are either Yes or No. Hopping Frequencies: It displays no. of freq. on which mobile is allowed to hop. viz. MA List for hopping of that sector.
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Mobile Allocation Index Offset (MAIO): It is the number which tells from which freq. from given MA list for sector hopping has to be started. E.g. 0 means sector will start from first freq. to hop up to 63. Hopping Sequence Number (HSN): Indicates sequence in which frequencies are allowed to hop from the MA List. 0 63. 0 for Cyclic Hopping, 1 – 63 random hopping sequences.
GSM RADIO PARAMETERS
RxLev: Receiving level in terms of dBm that mobile is receiving from the site. Subtracting 110 from the seen RxLev value on TEMS to get the dBm value. Range of -30 dBm to -110dBm. RxQual: Quality of voice which is measured on basis of BER. Range of RxQual 0 -7.
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FER: Frame Erasure Rate it represents the percentage of frames being dropped due to high number of non-corrected bit errors in the frame. It is indication of voice quality in network. BER Actual: Ratio of the number of bit errors to the total number of bits transmitted in a given time interval. BER is a measure for the voice quality in network. Depending on BER RxQual is measured. E,g, BER 0 to 0.2 % corresponds to RxQual 0. Max. BER countable and useful is up to 12.8 % which corresponds to RxQual of max. 7. SQI: SQI is a more sophisticated measure which is dedicated to reflecting the quality of the speech (as opposed to radio environment conditions). This means that when optimizing the speech quality in your network, SQI is the best criterion to use. SQI is updated at 0.5 s intervals. It is computed on basis of BER and FER. For EFR 30, FR – 21 & HR – 17 are respectively ideal values. C/I: The carrier-over-interference ratio is the ratio between the signal strength of the current serving cell and the signal strength of undesired (interfering) signal components. It should be at least > 9. MS Power Control Level: Phone transmit power ordered by the base station, It displays range of power control from 0 to 31 depending upon network design. E.g. 0 means no power control and 1 means level that is defined by operator. DTX: Discontinuous transmission (DTX) is a mechanism allowing the radio Dinec Global Resources Limited (DGRL)
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transmitter to be switched off during speech pauses. This feature reduces the power consumption of the transmitter, which is important for MSs, and decreases the overall interference level on the radio channels affecting the capacity of the network. TA: Value that the base station calculates from access bursts and sends to the mobile station (MS) enabling the MS to advance the timing of its transmissions to the BS so as to compensate for propagation delay. Value of 0 means MS in radius of 550mt from BS. RL Timeout Counter (Cur): This parameter defines the maximum value of the value of the radio link counter expressed in SACCH blocks. Range of 4 – 64 in step size of 4. It shows current value of RLT. Decrease by 1 but increase by 2. When it reaches zero it results in normal DROP call. RL Timeout Counter (Max): This parameter defines the maximum value of the value of the radio link counter expressed in SACCH blocks. Range of 4 – 64 in step size of 4. It shows current value of RLT. Normally 16, 20, 24. MS Behavior Modified: Indicates whether the phone’s behavior has been changed from the default. Most of what follows is applicable only to Sony Ericsson GSM phones. Empty string: No modification of phone behavior B: Modification of behavior not related to channel selection (the information elements Adjacent Scan, Band Control, Forced Power Class, Idle Channel Quality) C: Modification of channel selection
behavior
(the
information elements Disable Handover, Ignore Cell Barred, Dinec Global Resources Limited (DGRL)
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Prevent Handover List Active, Prevent Serving Cell List, Serving Cell List Active, Target Handover) G: Modification of GPRS behavior (the information elements Forced GPRS Class, Forced Multi-slot Class, Forced Quality of Service). Any combination of these letters may appear.
GSM SERVING + NEIGHBORS
Cell Name: Name that describes the neighboring cell as per
the cell-file. ARFCN: Channel number mobile receives as neighbor. BSIC: BSIC of the neighboring cell. RxLev: Receiving Level in dBm of neighboring cell. C1 & C2: These are the cell path loss criterion and cell
reselection criteria. Valid during idle mode of mobile station. C31 & C32: GPRS signal strength threshold criterion C31 and GPRS cell ranking criterion C32. Valid both in packet idle and packet dedicated mode.
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EGPRS LINE CHART
Sub-Network (SNDCP)
Dependent
Throughput
DL
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Convergence (Kbit/s):
Data
Protocol throughput Page 8
(including protocol headers, but excluding retransmissions) on downlink at SNDCP protocol level. The range is 0 – 400 kbit/s LLC Throughput DL (Kbit/s): Data throughput (including protocol headers, but excluding retransmissions) on downlink at the LLC protocol level. The range is 0 – 400 kbit/s RLC Throughput DL (Kbit/s): Data throughput (including protocol headers, but excluding retransmissions) on downlink at RLC protocol level. The range is 0 – 400 kbit/s Number of Used Timeslots DL: Number of timeslots in use on the downlink. . The range is 0 – 8 GSM DATA TIMESLOTS
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TS Channel Type: Type of channel in each timeslot on downlink. Channel type, also indicating which speech coder is used. For example, “TCH/F + FACCH/ F and SACCH/M”, “BCCH”, or “PDCH”. PDCH is the channel type for data in GSM. C/I Worst:
For
multi-slot
allocations:
Timeslot
list
corresponding to the C/I Worst element. The range is 0 – 7 and an argumented value of 0 – 511. 0 gives the timeslot of the channel having the worst C/I, etc. BER/TS: Bit error rate for each used timeslot. Valid for data services only. The range is 0 – 26% and an argumented value of 0 – 7. 0 represents the first used timeslot (not TS 0), etc. BLER/TS: Block error rate for each timeslot used. Valid for data services only. The range is 0 – 100% and an argumented value of 0 – 7. 0 represents the first used timeslot (not TS 0), etc. CS-n Data: These elements contain the distribution of coding scheme usage (on the downlink and for own data only) for each timeslot. The range is 0 – 100% and an argumented value of 0 – 7. 0 represents the first used timeslot (not TS 0), etc. MCS-n Data: These elements contain the distribution of modulation coding scheme usage (on the downlink and for own data only) for each timeslot. The range is 0 – 100% and an argumented value of 0 – 7. 0 represents the first used timeslot (not TS 0), etc.
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