Model Tuning Process on Aircom Asset

March 25, 2018 | Author: Raj Ranjan | Category: Antenna (Radio), Calibration, Radio Propagation, Map, Bandwidth (Signal Processing)


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ASSET WORKSHOP Model TuningMOBILINK-PAKISTAN Site Selection .AGENDA Aim of Model Tuning CW Measurement . Rajendra AIRCOM INTERNATIONAL Limited 2 .CW Drive Route Definition .Equipment configuration Model Tuning Process Model Calibration Analysis ASSET WORKSHOP-2007. Provide cost efficient Nominal Plan ASSET WORKSHOP-2007.Aim of Model Tuning Determine model parameters in accordance to realistic propagation effects existing within proposed regions. Rajendra AIRCOM INTERNATIONAL Limited 3 . Make sure calibrated model corresponds well with the collected data is essential. Minimise Standard Deviation Error. Rajendra AIRCOM INTERNATIONAL Limited 4 .CW Measurements and Model Calibration Process Propagation Model Requirements Identification Site Selection Drive Route Definition CW Survey Campaign Data Post Processing Data Data Validation Validation Calibration YES Report Pass Model? NO ASSET WORKSHOP-2007. Within geographic region of model Spread of site heights representative of network sites heights within modelled region Allow measurements in all clutter types Rooftop sites are preferred in a case test transmitter has to be mounted Ease of access No blocking objects in close vicinity Nothing unusual.CW MEASUREMENT More or 10 sites per model. Less number of sites can be considered if modelled geographical area is fairly small. we are characterising the majority of the network not the minority ASSET WORKSHOP-2007. Rajendra AIRCOM INTERNATIONAL Limited 5 . do not drive other lake side Avoid large blocking objects as high building or long roof Long enough to ensure sufficient data is captured Check map data validity ASSET WORKSHOP-2007.CW MEASUREMENT Distance Must account for expected coverage propagation Must account for expected interference propagation Clutter Sufficient measurement in all local clutter types ( >1000 ) Roads Avoid street canyons. cuttings etc Mix of radial and tangential roads Miscellaneous Do not plan a map along the roads with ground height above the transmitter antenna. if site is on the one side of the lake. tunnels. Good balance between measurements taken in LOS and NLOS situations Do not plan a route across a big water surface. Rajendra AIRCOM INTERNATIONAL Limited 6 . elevated roads. elevated roads. Rajendra AIRCOM INTERNATIONAL Limited 7 . tunnels. EiRP should be greater than 40dBm Raw/Averaged data Use Omni antenna with minimum vertical beam width of 12 degrees Directional antenna can be used but in post processing everything beyond 3dBm should be dismissed Driving Do not drive out of RX noise floor Avoid street canyons.CW MEASUREMENT Spectrum clearance During CW survey allocated test frequency shouldn’t be use for other purposes 10-15KHz bandwidth monitoring Check restrictions on test frequency TX EIRP Equipment configuration Accurate Radiated Power setting. cuttings etc Distance/Time triggering ASSET WORKSHOP-2007. The more data the model is more realistic ASSET WORKSHOP-2007. As stated before. Common practise is to have at least 30000 data. Rajendra AIRCOM INTERNATIONAL Limited 8 . 30000 data gives total driven distance of 30000x40λ=198km or 20km per site for 1800MHz range. 50 samples should be averaged and give the local mean. Common practice is to take 50 samples which gives one sample every 0. tuning can be performed with 10000 data or 22km per site. statistically sufficient number of data need to be collected.8λ. If this distance is not achievable due to limitation in drivable roads it is recommended to have more than 10 sites per model. in a case of modelling small geographical area with 3 sites.DATA REQUIREMENT In order for model to be realistic. Rajendra AIRCOM INTERNATIONAL Limited 9 . Check the driven routes against vectors within the map data. Location. Filter out any invalid data that may cause anomalies in the calibration process Make sure that details relating to a site (EIRP. Use Asset utilities to get visual representation of the received signal vs distance. Height.VALIDATION DATA Compare the site data (photographs. Antenna file) correspond to reports from CW Survey. ASSET WORKSHOP-2007. surrounding clutter and terrain profile) to the Clutter and DTM layer of the map data provided. ASSET WORKSHOP-2007.VALIDATION DATA Filter clutter types that have less than 500 bins. Unusually high signal level at far distance can be caused by reflection over big water surface. Rajendra AIRCOM INTERNATIONAL Limited 10 . Unusually weak signal level can be caused by driving behind blocking object. Filter out any file which shows extreme in signal level. or driving along route which is higher than antenna. Okumura –Hata can’t model above situations. therefore these data must be filtered out. Clutter offsets or them will be estimated later in the model tuning process. Rajendra AIRCOM INTERNATIONAL Limited 11 . This is because they relate to mobile height which in a typical cellular system is constant making these coefficients redundant. K6 <0 Above step can be easily fulfil by determining the delta range under Auto tune window ASSET WORKSHOP-2007. K7 >0 K3. K5. K2. K7 is the diffraction parameter. All K parameters must keep the same polarity as in the original Okumura Hata model K1.K PARAMETERS K3 and K4 are not altered. It can be determined by tuning just NLOS data. K PARAMETERS Default K PARAMETERS ASSET WORKSHOP-2007. Rajendra AIRCOM INTERNATIONAL Limited 12 . Rajendra AIRCOM INTERNATIONAL Limited 13 . Estimation is done relative to the clutter offsets with sufficient data. Clutter offsets must be realistic relative to each other. CLUTTER OFFSET Some through clutter offsets and clutter offsets need to be estimated due to insufficient data. Apply found k parameters.k6 and k7 locked and filter out distances above 700m. Water will have the smallest offset while building and forest the highest.K PARAMETERS K1 and K2 Near Calibration If model is not good close to the site. If standard deviation is still bad try with other distances until you find the best fit. for example up to 700m. ASSET WORKSHOP-2007. Tune model again with k5. Result will be k1near and k2 near. auto tune the model from 700m to 10k. Rajendra AIRCOM INTERNATIONAL Limited 14 .K PARAMETERS Mean error is usually altered after estimation of clutter offsets. ME can be easily bring back to 0 by changing k1 If mean error is ∆ change k1 to k1+ ∆ ASSET WORKSHOP-2007. Rajendra AIRCOM INTERNATIONAL Limited 15 .MODEL TUNING PRACTICAL IN ASSET LOAD CW DATA AND SETTING CW MEASUREMENT ASSET WORKSHOP-2007. MODEL TUNING PRACTICAL IN ASSET DEFINE DEFAULT MODEL AND FILTER ASSET WORKSHOP-2007. Rajendra AIRCOM INTERNATIONAL Limited 16 . Rajendra AIRCOM INTERNATIONAL Limited 17 .MODEL TUNING PRACTICAL IN ASSET GRAPH FOR DATA VALIDATION ASSET WORKSHOP-2007. Rajendra AIRCOM INTERNATIONAL Limited 18 .MODEL TUNING PRACTICAL IN ASSET CW Signal CW Signal ERROR ASSET WORKSHOP-2007. Rajendra AIRCOM INTERNATIONAL Limited 19 .MODEL TUNING PRACTICAL IN ASSET AUTO TUNE ASSET WORKSHOP-2007.
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