BHARAT SANCHAR NIGAM LIMITED OFFICE OF THE CHIEF GENERAL MANAGER, T&D CIRCLE, SANCHAR VIKAS BHAVAN, JABALPUR-482001 (MP)
ENGINEERING INSTRUCTIONS
ACCEPTANCE TESTING OF BTS IN GSM ERICSSON [EI No.: - ELECTORNIC SWITCHING/ GSM/ AT – 002]
1.0
SCOPE
This Engineering Instruction describes about acceptance testing procedure of GSM BTS of Ericsson. 2.0
GENERAL
The BTS (Base Transceiver Station) is the Radio or Air-interface with mobile phone on move (Subscriber’s Mobile Set) to log on to the network enabling the Calling Subscribers to be switched to the Called party through BSC & MSC. The Access method used is FDMA/TDMA. The directional antenna is either dual polarised or single cross polarised. To complete the function, software is playing the dominant roll and as such most of the tests are derived from software information rather than actual measurement except the output power of the Transmitter and VSWR of the feeder wave-guide. Besides these, Hardware conformity, physical verification of the equipment, installation and layout, Infrastructure of the site is incorporated in the TestSchedule. 3.0
PRE-REQUISITE OF TEST
The site-specific document containing the BTS site hardware and software details, approved layout details, etc. shall be available at site prior to testing. Check that BTS Equipment hardware has been installed perfectly in all respect. 4.0
MEASURING INSTRUMENT REQUIRED
(i) (ii) (iii) (iv)
Digital Multimeter, Site-master with accessories, OMT, TEMS (Test Engineering Mobile Set).
5.0
TEST PROCEDURE
The testing of the GSM BTS consists of testing of BTS equipment and testing of the infrastructure provided for the BTS viz. Power Plant, Battery, Tower, Earthing, Engine Alternator, Fire detection/fighting system, media, anti-static flooring, etc. The scope of this EI is limited to the testing of BTS equipment only. The testing of the infrastructure shall be carried in accordance with the relevant test schedule of T&D Circle. 5.1
Site Details (General)
TECHNICAL & DEVELOPMENT CIRCLE ENGINEERING INSTRUCTION
ACCEPTANCE TESTING OF BTS IN GSM ERICSSON
Check the Site ID, Name of the BTS-Site (whether BSNL or Non-BSNL), Location Area and the Base-Station Identity Code (BSIC) by using TEMS phone and verify it from the site document. 5.2
Site Details (Equipment)
Physical verification with respect to site specific document of the number of cabinet used with serial no, Number of TRUS installed, Quantity and Type of Antenna (whether cross or dual polarised and vertical or horizontal) are to be done and recorded in the TestSheet. [21 dbi 30° cross-polarised Antenna used for High-Way BTS-Site and for City BTS-Site it is 18 dbi ±45 vertical dual polarised Antenna]. Frequencies (ARFCN) used & Cell ID for Sector- I, II & III and Cell-ID also be noted from TEMS and verified with site document. 5.3
Voltage Drop
The difference between the Battery terminal voltage and voltage available at BTS input should be less than 1 Volt. 5.4
Documents Provided
BTS document should be readily available at the BTS-Site. SACFA clearance also shall be provided for the frequencies used at the site. 5.5
Location, Alignment & Rigidity
Check that the equipment is installed at the location shown in approved lay-out plan and rigidity as well as alignment of Equipment. Also check that sufficient space is available for BTS cabinet door movement. 5.6
Hardware And Software Conformity Check
Check the BTS Hardware and Software conformity as per site-specific document physically and by OMT respectively. 5.7
Cable Laying And Termination
Check that the power cables and PCM cables are neatly laid, terminated and labeled as per the site document. The power cables shall be provided through fuses/circuit breakers. The DDF should be properly installed and neatly labeled. 5.8
Redundancy Test of PSU
PSUs (Power Supply Units) are four in numbers and work in load sharing mode and also provides redundancy for cabinet-load. Even, more than one PSU may be switched off depending upon the number of TRU used, the system should not fail. Rotationally all
[EI No.: - ELECTORNIC SWITCHING/ GSM / AT – 002] Page 2 of 5
TECHNICAL & DEVELOPMENT CIRCLE ENGINEERING INSTRUCTION
ACCEPTANCE TESTING OF BTS IN GSM ERICSSON
PSU one at a time may be switched off and on, check that BTS functioning is not affected. 5.9
Initialisation and Self-Diagnostic Test
The restart and recovery function is used to determine whether a unit is capable of being brought into operation by itself through initialisation. The BTS under normal operation should be switched OFF and then ON. The BTS on power ON first carries out selfdiagnostic and then carries out the software initialisation. The normal BTS operation shall be restored within five minutes approx. Also verify the function of the ‘CPU RESET’ button to reset all the sub-units of the BTS and the BTS shall function normally. 5.10
Alarm Test
The alarm test in BTS consists of two parts (1) System Alarm tests and (2) Infrastructure Alarm tests. 5.10.1 System Alarm Test In BTS, a number of system alarms can be generated. Whenever a system alarm condition exists, the ‘FAULT’ LED on the concerned unit, for e.g. DXU, CDU, ECU and PSU, glows and a corresponding alarm message occurs in the MSC. The alarm can be simulated by (1) disconnecting E-1 link for DXU, (2) by disconnecting the wave guide for CDU, (3) by switching off all the fans for ECU and (4) Switching off Power supply for PSU. On simulation of the above alarms, verify that the ‘FAULT’ LED of the concerned unit glows. Also verify that ‘BS’ LED located on DXU, indicating occurrence of any fault in the base station, is lighted. The alarm text message corresponding to the simulation should be available in the MSC. Remove the alarm simulation and verify that alarm LEDs goes OFF and alarm message is cleared. 5.10.2 Infrastructure Alarm Test The BTS can collect, interpret and display sixteen numbers of External Alarms. Some of these alarms are Mains fail alarm, Fire alarm, Temp. Alarm, Door Alarm, etc. These alarms have designated terminals at the alarm collection point and can be simulated by giving proper alarm signal. Simulate External Alarm points and verify that the corresponding alarm text appears along with glowing of ‘EXTN’ LED on DXU. 5.11
Transmitter O/P Power Measurement/Control
Connect OMT on RS.232 port of DXU. The TX power can be set in the range of +30dbm to +45 dbm and the same can be verified at the TX output by Site-master or powermeter.
[EI No.: - ELECTORNIC SWITCHING/ GSM / AT – 002] Page 3 of 5
TECHNICAL & DEVELOPMENT CIRCLE ENGINEERING INSTRUCTION
ACCEPTANCE TESTING OF BTS IN GSM ERICSSON
5.12
Antenna & Feeder Test
Following tests are carried on the wave guide and the antenna. 5.12.1 Laying Of Feeder Wave guide The feeder wave-guide should be neatly laid over the runway with proper clamps and it should be taken out of the equipment room through a water protected ROXTEK wall pit. The wave-guide should not sharp bending. 5.12.2 Protection & Sealing Of Wave guide The wave-guides shall be protected from damage by External elements outside the building. This can be done by providing iron-mesh over the wave-guides along the Runway. The antenna coupling of the wave-guides shall be properly sealed to prevent ingress of moisture, which may affect the VSWR, and thereby the coverage provided by the BTS. 5.12.3 Labeling of Wave guide Proper labeling is to be done on wave guide to identify the TRU and Antenna related to it. 5.12.4 Earthing Of Feeder Wave guide Earthing at top and bottom of vertical part of the wave-guide to be checked. In horizontal part if it is more than 50 meter along the Runway. Earthing is to be done with bare copper cable connected to tower. 5.12.5 VSWR Measurement The Site-master (VSWR measuring instrument) is calibrated for 890 MHz – 960 MHz range and the feeder under test is disconnected from CDU and connected to the Test port. The measured value should be better than 1.3 5.13
Tower Test
The tower on which the antennae are mounted form a critical infrastructure component of the BTS site. If the tower is new, all tests of new tower as prescribed by T&D Circle test schedule should be conducted and cleared. If the tower exists, verify that all the legs of the tower are properly connected to the ring earth. The tower should have lightening spike, which shall be connected to the earth through a separate copper cable. 5.14
Tower Mounted Amplifier (Where Ever Applicable)
The TMA (Tower Mounted Amplifier) is used for high power transmission in highway BTS-site. Required voltage for the Amplifier is supplied by the bias-injector. Healthy [EI No.: - ELECTORNIC SWITCHING/ GSM / AT – 002] Page 4 of 5
TECHNICAL & DEVELOPMENT CIRCLE ENGINEERING INSTRUCTION
ACCEPTANCE TESTING OF BTS IN GSM ERICSSON
condition of the TMA is indicated by the Green-lamp on control-module installed near to the Bay. 5.15
MINILINK 15GHz Digital M/W System Test (Where Ever Applicable)
In some cases the BTS – BSC 2 Mbps media connectivity may be provided through Minilink of M/s. Ericsson, which is a 15GHz Digital Microwave system. The test for the same is required to be taken as per approved survey report and digital microwave test schedule covering following main items. a. b. c. d. e. f. 5.16
Trans Power (as per specification of manufacturer). Receive Power (as per survey report). Trans frequency (as assigned for the link). 2 Mbps check (as per G-703). Stability test. VSWR of the feeder cable.
Call Test
5.16.1 Calls For Cell Id Establish a call with the help of TEMS in the BTS coverage area, Cell ID can be checked and by shutdown of the TRU concerned to the Cell of the particular sector this information can be confirmed. This operation should be repeated for each sector. 5.16.2 Intra-BTS Call Handover Test After establishing a call with the help of TEMS in a particular cell it is to observe that the call does not drop while moving around BTS with smooth hand-over of the call from one cell to other cell of the BTS. Change of cell can be confirmed by the change of ARFCN and Cell ID of the Cell. 5.16.3 Calls to PSTN/PLMN A number of calls to PSTN & other PLMN may be established by TEMS and quality of speech may be checked and noted in the test sheet. 6.0
CONCLUSION
7.0
The EI describes the testing procedure for BTS of M/s. Ericsson. The infrastructure provided for BTS plays an equal important role in successful and continuous functioning of the BTS and therefore should be tested. Any discrepancies observed during testing should be brought to the notice of installer for rectification. END Chief General Manager Technical & Development Circle Jabalpur- 482001 [EI No.: - ELECTORNIC SWITCHING/ GSM / AT – 002] Page 5 of 5
