DRIVE TEST IN MOBILE COMMUNICATION
The Drive test is a test that usually after a new site installation. At a Drive test ,it is used to verify several RF parameters like coverage, channel quality etc. . Basically there are 3 main Drive tests can be listed as below.
- SSV - single site verification test
- Cluster – more than one sites have to be subjected during this test
- Bench mark - there are many service providers assigning in the test
SSV- single site verification
In single site verification a DT Engineering team has to visits the site. They used modern facility of GPS to locate the site. Usually they used TEMS software for Drive test and the GPS facility also have included to that TEMS software. At the beginning it is worth to test the probability that the site has swap. Therefore keeps a record file for swap test and goes around the site to see the signal coverage and verifying that site have no swap . (if there any have to be corrected with connection of IDU) after the swap verification we started the call tests and hand over tests .
TEMS TM, TEst Mobile System, is the optimization software solution package from ERICSSON. It can perform Real-time diagnostics, Autonomous Monitoring, Network performance evaluation which greatly reduces the complexity inherentto large geographically variant GSM and UMTS Radio Network Planning.
Drive Test Equipment Set(Figure 5.4)
- power supply needed, usually using inverter in the vehicle from laptop, GPS and 3MS
- a GPS should use
- MS position should be carefully chosen and stable during drive test
Swap test of (SSV)
- At the beginning a vehicle that has the drive test setup of equipment goes around the site as shown in figure -5.7.1. While go around the site keeps a record of TEMS software.
- If there no evidence of recode for swap there is no swap and if so as figure -5.7.2 can have probability to swap in DCS antenna of site, therefore we noted down the swap as possible to be them .
- Since swap is notifying by TEMS , we check the azimuths angles of DES antennas which cell files given by planning section .
- If there are no errors in azimuths angles, we have swap in DCS sector antennas. But error must corrected if any error in cell files
- If there is a swap we have to correct that swap with IDU in BTS
Call test of (SSV)
The call tests subjected for all three DCS antennas place in GSM tower .Therefore this test doing near by the site about 300m in range and for all DCS sectors respectively. We followed following tests with TEMS software.
- Makes about 15 calls or more (depend on vendor requirement)
In some case of call tests there are failures due to signal weakening and mobiles disconnections.
Hand over test of (SSV)
There are three kind of hand over test have to be done for SSV. Those handover tests can be listed as bellow
- DCS sector antenna hand over test in same site
- DCS sector antenna hand over test with neighbors sites
- I-rate hand over test ( ie signal s verification test for change signals 3G to 2G )
DCS sector hand over test in same site
This test is similar to swap test, but consider only hand over of DCS sector antennas in same site. That is we test how the DCS sectors handover one to others in same site. Figure-5.7.1 shows the way of done this in a typical drive test. More it shows clock wise and anti-clock wise directional verification for DCS sectors handover in same site. In here that we select one DCS sector antenna for the TEMS and observed how the sector antenna hand over to corresponding sector antenna of neighboring DCS antenna of same site.
DCS sector antennas hand over test in same site(Figure 5.7.1)
- Select TEMS software to the band 900MHz for both MS-1 and MS-2
- Take a call MS-1 to MS-2
- Set MS-3 for data download
DCS sector hand over test with neighbor sites
Consider only hand over of DCS sector antennas with neighbor sites. That is we test how the DCS sectors handover one to other with neighbor sites for each DCS. Figure-5.7.2 shows the typical hand over test. In here that we select one DCS sector antenna for the TEMS and observed how the sector antenna hand over to corresponding sector antenna of neighboring DCS antenna of neighbor site.
- Select TEMS software to the band 900MHz and 1800MHz for both MS-1 and MS-2
- Set MS-3 to rack to normal mode
- Keeps MS-1 ideal and take a long call for a test number
- Set MS3- for data download
: hand over test with neighbor sites (Figure 5.7.2)
I-rate handover test
The test assigning 3G signals handover in to 2G signals. During this test it is necessary to check all DCS sectors how hand over 3G signals into 2G signals. Hence it is necessary to traveled as shown in figure-5.7.3. But we can do this, covering the relevant MS- 3 as we are doing the DT outside the site.