DRIVE TEST ACCEPTANCE CRITERIA FOR ANY SWAP/REFRESH PROJECT Date Author
23/06/2005 Dr; Hatem Mokhtari
Summary 1. 2. 3. 4. 5. 6. 7. 8. 9.
Scope of Work Input Data List of checks to be performed for the BEFORE Drive Tests List of checks to be performed for the AFTER Drive Tests Checklist Summary Decisional Flowchart Dual Band Sites Conclusion Annex
1. Scope of Work This document aims at providing clear acceptance criteria for the drive tests before and after the swap. It encompasses study cases with drive test and route snapshots. A decisional flowchart is also provided in the annex to help accept or reject a drive test. Furthermore, because before and after drive tests have different acceptance criteria, the document presents both specific and intrinsic assessment methods. The idea is, indeed, to provide a common acceptance process within THE COMPANY to focus on the main issues and have a faster, and yet more effective drive test validation process. Adopting a common assessment method will give THE COMPANY Engineers more pro activity and, therefore, avoid deadline FN8 production and overhead costs for THE COMPANY. 2. Input Data This document relies on tools and data received from THE COMPANY third party Drive Test supplier. The tools are basically the most commonly used ones, namely: TEMS Investigation, Actix Analyzer, and Mapinfo. Drive tests are supplied by First Line Telecom. Besides, THE COMPANY have developed customized applications to automatically produce FN8s in Excel file as required by the client. The KPI segment is out of scope of this document. Before starting any DT assessment, the log files both MOC MTC and normal log files have to be available. If any is missing, the DT can be deemed as incomplete and therefore rejected. 3. List of checks to be performed for the BEFORE Drive Tests Before doing anything, it is strongly advised to open the CHECKLIST excel file supplied by First Line. This should enable the engineer to immediately pinpoint DT problems that might have been encountered or if any route closed for work that could markedly influence the results. Also this file could contain DT problems such as major outage on a site, drop calls noted, etc. Drive tests performed before the swap have to fulfill certain criteria. These are summarized as followed: 3.1. Rxlev fast glance check The DT route as defined and agreed by First Line Telecom has to be loaded in Mapinfo. Afterwards, The DT is thus compared, eventually superimposed on the same layer of the DT route. The Route and DT should have sufficient match. We may assume that roughly 80% of the route is driven. At this stage, if the route is not sufficiently represented the DT can me considered as void and therefore rejected. Immediately, the Engineer has to report it to The Troubleshooting team AND the DT coordinator, who will take necessary action to ask the supplier (FLT) to re-do the DT. The DT snapshots have to be put in an excel file and copied onto
FLT Faulty DT Folder. For example for the site 087G1 the faulty logfiles should be copied in : ftp://bel-ftp01.The Companynet.com/first.line/Tems.LogFiles/Faulty%20Logfiles/LEVEL3/087G1/
3.2. Seamless Coverage Sometimes the DT show that GPS data are lost or the measurements could not be reported by the MS. In this case one may pinpoint this during the initial check. Too many scattered data may lead to misinterpretation and tedious comparison with the after measurements. When this happens, the Engineer should inform the TS Team and the DT coordinator. DT logfiles should show quasi uniform distribution of the samples on each route. We may tolerate, of course, some scattered data but widespread distribution is not acceptable. 4. List of checks to be performed for the AFTER Drive Tests At this stage, we assume that DT Before is already accepted. The Engineer will have generated the FN8 excel file for the site under study. Subsequent step is the comparison between the DT route and DT After as in the before check as mentioned in section 3. If the match between the DT route and the DT itself is acceptable, we should look if the coverage does not look poor. Sometimes, in the after period, a sector cell is down for I&C issues and this can be seen on the DT itself. Immediately the Engineers should alert the TS Team and DT Coordinator. The drive test cannot be used for comparison. Too less samples in the after period can lead to rejection of the After DT. Examples are given in the annex with DT snapshots. The route sense has to be the same in the Before/After otherwise BCCH coverage maps and HO areas will be shifted and therefore completely different, making the comparison impossible. 5. Checklist summary 5.1. Before DT Checklist - Number of samples higher than 1000 - DT Route and DT itself should match for more than 80% - Each sector is sufficiently represented - Major roads are driven as defined in DT Routes - No sector cell is locked or shutdown during the DT day Important Note : Initial assessment can be done using TEMS/ACTIX/FN8N Tool. There is no requirement as what tool to use. As long as enough info can be monitored and the site comprehensively assessed, feel free to use either tool. 5.2. After DT Checklist - Number of samples should lie within a reasonable range compared to the Before. Say, 10% higher or lower is tolerable
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DT Route and DT itself should match for more than 80% After DT and before DT should visually match at 90% approximately No cross feeder is present. This is identified by assessing best server, HO and especially strange drop calls. Make sure that the routes are driven in the same way in both Before-After periods. E.g. from point A to point B in both periods. This can be seen on the BCCH Map on FN8 Sheets. Make sure that there is no poor coverage in the vicinity of a sector of the site under test ; this may lead to poor coverage and quality. On FN8, check the Rxlev histogram. If the difference is much higher than 3 dB please alert the TS Team and DT Coordinator.
6. Decisional Flowchart
“BEFORE” DT CHECK
No
- Normal & MOCMTC Files available ?
Yes Use FN8 Tool to produce the “Before” Maps and Histograms Open DT Route in Mapinfo
Display RxLev Map
- DT Route and DT Log match > 80 % ? - Major roads covered ? - Site Design Targets covered ?
Yes
“Before” DT Accepted Wait for the “After” DT
No
DT Rejected
Immediately Inform Hatem or David by email Provide a copy of the snapshot onto FTP FLT Faulty Directory
“AFTER” DT CHECK
No
- Normal & MOCMTC Files available ?
Yes
GENERATE FN8 FN8 Sheet : Values Read Total Number of Samples
Samples After > 90% of Samples Before
No
Yes
Immediately Inform Hatem or David by email
FN8 Sheet : FN8N Average Rxlev Sub Check
Yes | AverageAfter AverageBefore| > 3.5 dB
DT Rejected
Provide a copy of the snapshot onto FTP FLT Faulty Directory
No FN8 Sheet : RxLev Map Check the visual match and # Samples for each environment category
(1)
(2)
(3)
(1)
(2)
(3)
No Samples for each category are within comparable range?
Yes FN8 Sheet : BCCH Map This sheet should help assess the route sense and that DT Before/After done in the same directions
BCCH Coverage is roughly the same ? (DT direction the same Before/After)
No
Yes
Cross-Feeder Issue? (check Drop calls, HO area, and Quality)
(3)
Yes
Drive Tests Before and After are Acceptable and FN8 can be assessed to cope with Mobistar Coverage Quality Requirements
7. Dual Band Sites The following applies to DUAL BAND SITES ONLY ! In the Before, if MS2 is not locked on 900 the Drive Test MUST BE REJECTED !!! The same rule applies for the AFTER. If MS2 is not locked on 900 the Drive Test is rejected and has to be redone !!! 8. Conclusion The document provided a generic process based on both our experience in assessing DT and FN8 analyses, but on common sense as well. Subsequent improvement still can be possible.
9. Annex
Example of mismatch between DT Route (blue) and DT logfile (Green)
Example of Logfile and route mismatch between Before and After periods
The number of sample in Deep indoor are completely imbalanced and the drive test in the After period should be “Re-DONE
