Alcatel-Lucent Drive Test-1 Part-1.pdf

Drive Test Overview

Created by Pulok Sinha ((Trainer,, ALUMS)) 09320096525 All Rights Reserved © Alcatel-Lucent 2009

Objectives In this session following aspects will be covered: ¾ Drive Test and its significance. ¾ Drive Test kit and its accessories. ¾ Basic definition ¾ Process involved in Drive Test ¾ Basic Rules of Drive Test ¾General DT Kit Issue

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All Rights Reserved © Alcatel-Lucent 2009

Drive Test and Its Significance

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Drive Test and Its Significance Definition: ¾ Drive test is real time process by which various network parameters of an operational network are gathered and are further analyzed for various problems if exist. • Analysis of Downlink Network performance • Network optimization. • Problem Indicator

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Drive Test and Its Significance Significance of Drive Test is to: 9Verify performance of new sites 9Verify Sectorizations 9Verify Frequency Plan 9Verify coverage 9Verify handovers

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Drive Test and Its Significance Significance of Drive Test is to: 9Verify Interference 9Verify Overshooting sites 9Verify data after Re–Homes 9Verify Faulty Installations 9Benchmarking

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Drive Test and Its Significance Modes of Drive Test: ¾Idle mode Drive test: – To check the network Coverage

¾Dedicated Mode Drive Test – To check the voice or data performance

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Drive Test Kit and its Accessories

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Drive Test Kit and its Accessories Drive Test Kit Kit:: • • • • • •

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Laptop Drive Test Software Test Mobile Global Positioning System (GPS) ( ) Cables and Connectors Drivers Software


Drive Test Kit and its Accessories Laptop: It basically is the user interface in which the Drive Test Software is installed and is used to collect and store the log files.

Drive Test Software: The drive Test software controls the whole process and integrates the information received by the test mobile with that provided by the GPS receiver. receiver

Test Mobile: The test mobile monitors the GSM channels for the appropriate messages and can simulate subscriber actions.

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Drive Test Kit and its Accessories Global Positioning System (GPS): The GPS provides positioning information to be used in conjunction with the collated network data.

Cables and Connectors: Cables and connectors are needed for Connection of external accessories. For Example - like Data Cable for Mobile, GPS Cable, PCMCIA Card, etc

Drivers Software: The external accessories may not be compatible to the Laptop so specific drivers of those are needed to be installed.

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Drive Test Kit and its Accessories Available Drive Test Tools: • TEMS (Ericson) • NEMO (Anite) • AGILENT (Agilent Technologies) • NTAS (Beijing Rising Technology Co. Ltd.)

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Basic Definition

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Basic Definition Decibel (dB) • dB is a relative unit of measurement used to describe power gain or loss. • Decibel is logarithmic value that represent ratio of two given power. power • dB can be expressed as follows: X dB = 10 llog (Po / Pin) • The powers Po ad Pin must be in the same units. If the units are not compatible, compatible then they should be transformed. transformed • Equal power corresponds to 0dB.

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Basic Definition Decibel with respect to milli milli--watt (dBm) (dBm) • dBm is a standard unit for measuring levels of power in relation to a 1 milli-watt reference signal. • It is different from the dB because A dB has no particular defined reference while a dBm is referenced to a specific quantity: the milli-watt (1/1000 of a watt). • dBm can be expressed as follows: dBm =10 log10 (Signal Power / .001 watt )

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Basic Definition Propagation Mechanisms Reflection f • Occurs when a wave impinges upon a smooth surface. • Dimensions of the surface are large relative to λ. • Reflections R fl ti occur from f th surface the f off the th earth, th from f b ildi buildings, walls, mountains, etc.

Diffraction (Shadowing) • Occurs when the path is blocked by an object with large dimensions relative to λ and sharp irregularities (edges). (edges) • Diffraction gives rise to bending of waves around the obstacle.

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Basic Definition Scattering • Occurs when a wave impinges upon an object with dimensions on the order of λ or less, causing the reflected energy to spread out or “scatter” in many directions. • Small objects such as street lights, signs, & leaves cause scattering

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Basic Definition Antennas • Antenna is an essential p part of a transmitting g or receiving g system which is designed to radiate or to receive electromagnetic waves. •A An antenna t can also l b viewed be i d as a transitional t iti l structure t t between free-space and a transmission line (such as a coaxial line). • An important property of an antenna is the ability to focus and shape the radiated power in space e.g.: it enhances the power in some wanted directions and suppresses pp the p power in other directions. • Many different types and mechanical forms of antennas exist and each type is specifically designed for special purposes. purposes All Rights Reserved © Alcatel-Lucent 2009

Basic Definition Antenna Types In mobile communications two main categories of antennas used are:

− Omni directional antenna These antennas radiates equally in all horizontal direction.


Basic Definition − Directional antenna •

These antennas are mostly used to get higher gain compared to Omni-directional antenna and to minimise interference effects in the network.

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In these type of antennas, the radiation is directed at a specific angle instead of uniformly across all azimuth angles in case of Omni antennas.


Basic Definition Radiation Pattern •

The main characteristics of antenna is the radiation pattern.

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The antenna pattern is a graphical representation in three dimensions of the radiation of the antenna as a function of angular direction.

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Antenna radiation performance is usually measured and recorded in two orthogonal principal planes (E-Plane and Hplane or vertical and horizontal planes). planes)

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The pattern of most base station antennas contains a main lobe and several minor lobes, termed side lobes.

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A side lobe occurring in space in the direction opposite to the main lobe is called back lobe.


Basic Definition Radiation Pattern


Basic Definition Directivity of Antenna: • Directivity is the ability of an antenna to focus energy in a particular direction when transmitting or to receive energy better from a particular direction when receiving.

G i off A Gain Antenna: t • The gain is a measure of how much of the input power is concentrated in a particular direction. • It is expressed with respect to a hypothetical isotropic antenna, which radiates equally in all directions. • The relation between gain and directivity includes a new parameter “η“ which describes the efficiency of the antenna.

G=η.D η 23


Basic Definition Beamwidth of an Antenna: • Beamwidth is usually understood to mean the half-power beamwidth. • Half power Beamwidth (HPBW) is the angle between the halfpower p p points of the main lobe, referenced to the p peak power p of main lobe. • Beam width is categorized as: −

Horizontal Beamwidth

−

Vertical Beamwidth

• Beamwidth is measured in degrees.

Beamwidth

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Basic Definition Horizontal Beamwidth: •

Horizontal beamwidth is the beamwidth of the radiation pattern in Horizontal Plane .

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Generally, in City, antenna with 65⁰ Horizontal Beamwidth is g y antenna with 33⁰ Horizontal Beam width used and in highway is used.

Vertical Beamwidth: •

Vertical Beamwidth of an antenna is the beamwidth of the radiation pattern in vertical plane.

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Vertical beamwidth Varies from 4⁰ - 8⁰ depending upon the model of the antenna

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Basic Definition

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Basic Definition Relation between Beam width, Gain and Directivity

Beamwidth

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G i Gain


Di Directivity i i

Basic Definition Azimuth: • An azimuth is an angular measurement in a spherical coordinate system. It gives apparent direction of an object • It is measured in degrees. • Measured with help of compass

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Basic Definition Obstacle requirement


Basic Definition Antenna Tilt: •

The tilting of the vertical main lobe towards the ground by specific angle with respect to horizon is known Antenna tilting.

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The Maximum power of the lobe is at zero and can be place within the cell by y down tilting g the antenna.

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Down tilt can be use to:

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Improve the coverage

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Reduce interference

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Adjust the cell radius

Basically there are two types of Down tilting −

Mechanical Tilt

−

Electrical Tilt


Basic Definition Mechanical Down tilt

Electrical Down Tilt

¾In

Mechanical down tilting, antenna is physically down tilted towards the ground.

¾In

¾In

a mechanical down tilt as the front lobe moves downward the back lobe moves upwards.

¾Electrical

¾Side

¾In

lobe increase with mechanical down tilting

Electrical down tilt, the beam is tilted by altering the signal phasing. tilting g is done by y using the tilt knob integrated in the antenna

Electrical down tilting, g, all the lobes (main, back as well as ¾Mechanical tilt have no impact side) has distinct advantage of tilting on the gain. ¾In electrical down tilting, gain also reduces in all direction

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Basic Definition

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Basic Definition

Mechanically tilted Antenna 33

Electrically tilted Antenna All Rights Reserved © Alcatel-Lucent 2009

Basic Definition Multipath Propagation: • • • • •

Multipath, p , is the result of reflections and scattering g of radio waves due to buildings, mountains and other objects, etc. Multipath, in effect, creates multiple transmission path of the signal which arrive at the receiver at different times When the components are in phase, the signal gets added. When they arrive out of phase, they cancel each other. Give rise to Rayleigh Fading − Ricean fading −

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Basic Definition Rayleigh Fading The Rayleigh fading is applicable to obstructed propagation paths. • All the signals are NLOS signals and there is no dominant direct path. • Signals from all paths have comparable signal strengths. • The instantaneous received power seen by a moving antenna becomes a random variable depending on the location of the antenna. •


Basic Definition Ricean Fading This phenomenon is due to multipath propagation of the signal. • In this case there is a partially scattered field. • One dominant signal. g • Others are weaker. •


Basic Definition Diversity: •

Diversity Di it techniques t h i i an effective is ff ti means which hi h enhances h th the immunity of the communication system to the multipath fading.

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Diversity reception is a way to improve the quality and strength of the signal arriving at the base station, by receiving it in several independent ways

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Two forms of diversity reception often employed are:

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−

Space diversity

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Polarization diversity


Basic Definition Spatial (Space) Diversity • The spatial diversity antenna system is constructed by physically separating two receiving base station antennas. • If they are far apart, the received signals will be independent of each other. • If one has suffered fading, the other may not. • A suitable distance is generally about 10 wavelengths (10λ) • Plan Pl views i off two t possible ibl tri-sectored t i t d site it antenna t systems t

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Basic Definition Polarisation •

Polarisation l is the h propagation off the h electric l f ld vector . field

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Antennas used in cellular communications are usually vertically polarised or cross polarised.

Dual Polarised Antennas •

A dual-polarisation antenna consists of two sets of radiating elements which radiate or, in reciprocal, receive two orthogonal polarised fields. fields

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Dual Polarised antenna are of 2 types

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−

Vertical Polarised

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C Crossed d Polarised P l i d


Basic Definition Vertical Polarized antenna: • Good diversity performance only in cities • Horizontal termination cannot be used for Tx

Cross Polarized antenna • Equivalent diversity results compared to space diversity either in cities or in rural areas • Both terminations are suitable for Rx and Tx

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Process Involved in Drive Test

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Process Involved in Drive Test Various Procedures in Drive Test:: Test

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Collection of Data

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Post Processing

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Analysis l off the h extracted d data. d

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Suggesting changes based on y . the analysis


Process Involved in Drive Test Collection of Data Data:: Drive test involves collection of various radio parameters and air interference signal data as Log File. These Log Files are further used for post processing. processing

Post Processing Processing: g: From the data collected, various information can be extracted which depict the performance of BTS sites and the network as a whole.

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Process Involved in Drive Test Analysis of the extracted data data:: The information extracted from the collected data is then analysed. It is used to infer cause of detected problem in the network if there is any. any

Suggesting gg g changes g based on the analysis analysis: y : After detection of the causes of the deviation from the requirement or network related problems, measures are taken to improve the performance of the network and to match customer’s requirement.

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Process Involved in Drive Test Example of RxLev Plot:

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Process Involved in Drive Test Example of RxQual Plot:

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Process Involved in Drive Test Example of C/I Plot:

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Basic Rules for Drive Test

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Basic Rules for Drive Test Basic Points for drive test: ¾ As soon as sites are allocated, verify the data in database and plan your work accordingly. ¾ Update U d t the th cell ll file fil from f latest l t t database. d t b ¾ Before moving for the site, make sure that all the equipments are working properly. properly ¾ Performance Effecting Alarm Should be checked. ¾ While going to the site one must keep the Drive Test kit on and continuously track the Cell ID, BCCH ARFCN and BSIC to search the site.

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Basic Rules for Drive Test ¾ After reaching to the site one must verify the corresponding Cell ID, BCCH ARFCN and BSIC for the each sector. ¾ Pre-drive of the site need to be done. ¾ Physical Ph i l verification ifi ti viz. i Tower T h i ht building height, b ildi h i ht Total height, T t l tower height, GSM antenna height, Orientation, Tilt, Antenna Model etc. to be noted. ¾ Orientation of antenna should be taken properly and compass should be kept away from mobile, watch, any magnetic metal etc while measuring the orientation. ¾ Before using compass, its magnetic needle should be check properly p p y for any y shift.

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Basic Rules for Drive Test ¾ The tracker for physical data should me maintained regularly and should be send on regular basis. ¾ Feeder Cables are to be traced and the connectors need to be checked accordingly. If any anomalies are found, has to be reported and rectified accordingly. ¾ No obstacle should be there in main lobe of antenna. ¾ Proper route should be covered while drive, if routes not given all the roads in each sector should be covered. ¾ Driving the same road twice should be avoided or else record a separate log file.

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Basic Rules for Drive Test ¾ While driving over a bridge or in to a tunnel, always make a separate log file. ¾ While drive Short calls as well as Long calls are to be made. ¾ Short calls are to know whether calls will survive the setup and the termination successfully, it also determines the setup time. ¾ Long g calls are to test the hand over capabilities p as well as RX Level and RX Qual. ¾ Intra and inter handovers with each neighbours should be verified properly and should be reported if any anomalies found. ¾ The vehicle speed should be maintained between 20-40 km per h hour, d nott perform do f d i test drive t t att high hi h speed. d 52


Basic Rules for Drive Test ¾ Log files should not be too heavy nor should it be too small. Generally, Log file of 5-15 MB is recorded. ¾ Each and every log file should be named such that it gives a clear picture for what the log file is. For example, Type‐Of‐Drive _ Site‐Clutter‐Route‐Name _ Date ShortCall_Bandra_18‐07‐2010 / LongCall_BSC10_18‐07‐2010

¾ Check the log files, files if possible export it and then check, check before leaving the site. ¾ Distance and direction of any obstacles blocking in the way should be noted. ¾ Finally, report all sorts of problems.

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General DT Kit Issue

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General DT Kit Issue ¾ Check if dongle is properly connected. Dongle has to be connected first. ¾ Check if there is any loose connection, if it is there the tightened it. ¾ Check if the Mobile handsets and the GPS are defined in proper port ¾ Check if the respective drivers have been installed properly for example- phone driver data cable driver, example driver GPS driver, driver USB USBRS232 driver, etc ¾ If there is more than two handset check the level of each handset if there is difference in level then check the handsets first swapping the data cable and then swapping the ports. ─ By this, one can find if the problem is with the Handset, Data Cable Cab eo or Port. o t.

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General DT Kit Issue ¾ If problem is with the hand set then change the soft port of the handset and then verify it. ¾ If the kits gets hang close all application one by one then, turn off the KIT and Disconnect all the external peripherals, wait for some time and again start it, connect the dongle and then connect each of the peripherals one by one. ¾ Eye should be kept on MS connection as well as GPS connection as they y should not g get disconnected. ¾ Moreover, kit should be as per configuration to support required no of Handsets, else may face problem of kit hanging. ¾ The accessories should be kept properly and no rough handling should be there, else accessories may get damage decreasing the engineer o/p.

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Questions

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Alcatel-Lucent Drive Test-1 Part-1.pdf

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