Golden Ru les for collecting Data Dat a dur ing drive test: Do not drive away too much from the site. Drive in to the Site passing through the clutter as well as crossing the clutter Try and drive many roads close to the site unless the clutter is so important. Try to avoid driving the same road twice. Do not drive over a bridge or in to a tunnel inside a clutter area, otherwise take that parts of data a out of the data file collected for this clutter. 6) Make short calls and Long calls, Short calls is the average duration by customers, short calls are to know whether calls will survive the setup and the termination successfully, it also determines the setup time… 7) Long calls are to test the hand over capabilities. 8) The 6 neighboring cells are those who are listed in the scan list these do not mean that these are the only channels that the phone can see. 9) You have to make sure of the values you are getting out of the surveying equipment do actually make sense. 10) Know the exact power out of the antenna, ERP level, (Effective Radiation Power). 11) Everything about the antenna conditions, during the test time should be reported in the finalreport. 12) Weather conditions should be reported as well. 13) Know the distance and direction of any buildings blocking your way. 14) Finally, report all sorts of problems. 1) 2) 3) 4) 5)
Steps for DT For My Junior RF Engineer brothers Steps follow ed to perform Drive Test •Physical Verification •Alarm Checking •Frequency Plan Verification •Hardware Configuration Verification
Steps for DT-1
Physical Verification Physical Verification Verification is carried out by verifying physical parameter of the New Site with the TSSR (Technical Site Survey Report) such as Address, Lat, Long, Building Height, Antenna Height, Antenna Type, Orientation, Tilt. Alarm Verification Alarms are generated mainly due to number of reasons, and these needs to checked before Drive is being carried out for the Site. Alarms are checked from the NOC
(Network Operating Centre) and if found needs to be verified before drive being carried out. Frequency Plan Verification Frequency Plan can be verified from the NOC (Network Operating Centre) for BCCH and TCH frequencies being implemented as per the Site Integration Sheet sent to NOC (Network Operating Centre). Hardware Configuration Verification Hardware verification is performed to know the Site type, BTS Type, TRX Configuration, VSWR checking , Power measurement for each TRX.
Steps for DT-2 Following is the procedure a nd param eters that need to checked while perform ing Drive Test for a New Site. •CPC (Cell Parameter Check) •MOC (Mobile Originated Calls) •MTC (Mobile Terminated Calls – Prepaid to Postpaid) •SMS (Short Messaging Service) •GPRS •Intra Site Handover •Inter Site Handover •TRX Test •Idle Drive (Normal Drive & Frequency Lock Drive) •Dedicated Drive
Steps for DT-3
CPC (Cell Param eter Check) Given are the param eters that need to be checked while performing CPC. CGI (Cell Global Identity) cons ists if MCC+NCC+LAC+CI BCCH Frequency BSIC GSM Band
Steps for DT-4
MOC and MTC Given are parameter need to be checked while performing MOC and MTC RX Level (-47 dbm to -110dbm) RX Quality (0 to 7)
SQI (20 to 30) DTX HSN (Hopping Sequence Number) (0 to 63) MAIO Hopping Frequency C/ I Ratio (>15 dbm) C/ A Ratio (>12 dbm)
Steps for DT-5
GPRS (General Packet Radio System ) This is performed to check whether GPRS is working on the Site. This is done by browsing a web page in browser of the phone. For GPRS to be checked it is necessary to see that the handset is WAP, GPRS enabled.
Steps for DT-6
TRX Test TRX Test is done to check whether calls originated are being handled by all the TRX’s. Call made during the process is tracked by the MAIO number displayed on the screen for all the TRX’s. e.g. for Site of configuration 6 TRX per sector the MAIO values for TRX test shall be 0,1,2,3,4. Call can be originated on the BCCH or the TCH frequencies. Hence MAIO values will be reflected only for calls on TCH frequency and not on BCCH frequency.
Intra Site Hando ver Intra Handover is performed to check whether handover is taking place both ways on the Site. Handover is performed among all the Sectors of the Site.
Inter Site Hand over Inter Handover is performed to check whether handover is taking place both ways on the Site with it’s adjacent neighbor. Handover needs to checked mandatorarily for primary neighbor. Handover is performed with all the defined neighbor's in the integration sheet. Steps for DT-7 Idle Drive is performed in two fashion •Normal Drive
•Frequency Lock Drive Normal Drive This is done to frame the potential area of the new site planned. It also helps us to get to know the important neighboring sites for which the handover has to take place. Frequency Lock Drive This is done by locking the BCCH frequency of the serving cell and performing the drive for the same cell unless the mobile enters into No Service Mode. This is useful for making decision related to GSM antenna height, tilt, and orientation.
Dedicated Drive Dedicated drive is an important part of Drive Test. Here call is made to a test number and drive is done for the potential areas of the Site. During drive being carried out one has constantly monitor parameters such as RX Level, RX Quality, SQI, DTX, C/I Ratio, Hopping Channel, Neighbor list, TA (Timing Advance). Constant changes in these parameter are helpful for post Optimization of the site.
Definition of Radio P aram eters: •RxLev : Receiving level in terms of dBm that mobile is receiving from the site. Range of -30 dBm to 110dBm. •RxQual : Quality of voice which is measured on basis of BER. Range of RxQual 0 -7. •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 atleast > 9 . •MS Power Control Level : Displays range of power control from 0 to 8 depending upon network design. E.g. 0 means no power control and 1 means level that is defined by operator viz. 2 dBm less acc. To airtel. •DTX : Discontinuous transmission (DTX) is a mechanism allowing the radio 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 define the maximum 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 define the maximum 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 Mod ified : This window shows current settings for the mobile station, for instance whether handover is disabled or multiband r eporting enabled.
Definitions: .Time: It is system time of computer. .Cell nam e: It displays the name of the sector which is serving according to the cellfile that is loaded in TEMS. .CG I : It stands for the Cell Global Identity which is unique for every sector of the site. It consists ofMCC,MNC,LAC,CI. MCC : Mobile Country Code 0 – 999 MNC: Mobile Network Code 0 – 99 LAC : Location Area Code 0 65535 CI: Cell Identity 0 – 65535 •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. •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. 62. It is decoded by mobile on every Sync. Channel Message. •Mode: It is shows in which state is mobile operating, Idle, Dedicated & Packet. •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 orCBCH / 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 callsetup when it is getting SDCCH at that time it shows which SDCCH it is getting out of 8 available.E.g. 2. •Hopping Channel : It shows that current sector is having hopping feature or not. Values are 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.
•Mobile Allocation Inde x 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. •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.
