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Optimization & troubleshooting (CDMA)
 
Q1: Low Rxpower in the coverage
Q: Rx_power of donor signal is low.
A: Use the testing mobile or spectrum analyzer to find a place and direction where Rx_power is sufficient. Donor antenna need be line-of- sight from donor antenna.
 
Q: Donor antenna or cable connecting donor antenna to repeater is damaged.
A: Check VSWR of the antenna and cable. The standard is lower than 1.5. After then check the Rx_power of signal entering into the repeater.
 
Q: Repeater's gain setting is low.
A: Check and set the repeater's gain through OMT.
 
Q: Repeater's frequency has been changed.
A: Check and set repeater's working frequency through OMT.
 
Q: Cable or passive components of the coverage system are damaged.
A: Check VSWR of the coverage system.
 
Q2: Bad Ec/Io inside coverage
Q: Ec/Io of donor signal is bad.
A: Connect the donor antenna with testing mobile to find the suitable place and direction where Ec/Io is better than -7dB.
 
Q: Pilot channel pollution, which means more than 2 pilot channel with similar Ec/Io exist inside the coverage.
A: Adjust donor antenna to make sure the Ec/Io of primary pilot channel is at least 8dB better than secondary channel. Make sure the donor antenna is installed lower than 8F.
 
Q: Cable connecting with donor antenna and repeater has been damaged.
A: Test the VSWR of that cable. The criteria of repeater project is VSWR ≤ 1.5.
 
Q: Self-osciallation occurs. The AGC alarm of the repeater will be flickering. It can be observed that the Rx power is fluctuating, and Ec/Io is deteriorated inside the coverage.
A: To solve this problem, test the isolation at first, and then set the gain to be at least 15dB lower than isolation value.
 
Q: Interference exists inside the coverage.
A: Connect spectrum analyzer with 0dBi antenna to check the signal condition inside the coverage before and after coverage. Compare the test result to see whether interference exist or not.
 
Q3: Signal is excellent, but cannot make the call.
Q: Donor BTS hasn't enough capacity.
A: Consult with the operator or re - select the donor signal.
 
Q: BTS noise floor is increased.
A: Test and set repeater's UL gain properly. Make sure UL noise floor reaching BTS is lower than -114dBm.
 
Q: Search Windows setting of donor BTS is small, so that the signal amplified through repeater cannot be detected by mobile.
A: Increase the SRCH_WIN_A, SRCH_WIN_N and SRCH_WIN_R of the donor BTS.
 
Q: Unbalance between uplink and downlink.
A: Reset the gain, and make sure UL gain is lower than DL gain no more than 10dB for indoor coverage, and 5dB for outdoor coverage.
 
Q: Interference exist inside the coverage.
A: Check the signal inside the coverage by spectrum analyzer.
 
Q4: Call drop occurs rapidly in coverage area
Q: Self-osciallation occurs.
A: Test system's isolation, and set gain to be at least 15dB lower than isolation value.
 
Q: Pilot channel pollution.
A: Adjust donor antenna, and make sure that Ec/Io of primary pilot channel is 8dB better than secondary pilot channel.
 
Q: There's problem with donor BTS.
A: Reselect the donor BTS.
 
Q5: Signal Leak in coverage area
Q: Unreasonable design.
A: Take the method,more antennas with lower output power , to make the coverage. In indoor coverage, make sure each antenna's input power is less than 15dBm.
 
Q: Indoor service antenna is close to the window.
A: Move the Indoor service antenna away from the coverage edge. Another solution is use the directional antenna to send the signal from outside to inside to make coverage.
 
Q: Service antenna's output power is stronger than required value.
A: Decrease the service antenna's output power to be as low as possible when coverage requirement is enough.
 
Q: Surrounding has been changed.
A: Make site survey and re-design the project.
 
Optimization & troubleshooting (GSM)
 
Q1: Low Rxlev in the coverage
Q: Rxlev of donor signal is low.
A: Use the testing mobile or spectrum analyzer to find a place and direction where Rxlev is strong. Donor antenna need be line-of- sight from donor antenna.
 
Q: Donor antenna or cable connecting donor antenna to repeater is damaged.
A: Check VSWR of the antenna and cable. The standard is lower than 1.5. And then check the Rxlev of signal entering into the repeater.
 
Q: Repeater's gain setting is low.
A: Check and set the repeater's gain through OMT.
 
Q: Repeater's frequency has been changed.
A: Check and set repeater's working frequency through OMT.
 
Q: Cable or passive components of the coverage system are damaged.
A: Check VSWR of the coverage system.
 
Q2: Bad Rxqual in Coverage
Q: Rxqual of donor signal is bad.
A: Connect the donor antenna with testing mobile to find the suitable place and direction where Rxqual is better than 3.
 
Q: Pilot channel pollution, which means more than two donor signals with similar Rxlev exist inside the coverage.
A: Adjust donor antenna to make sure the Rxlev of primary BCCH is at least 6dB stronger than secondary BCCH. Make sure the donor antenna is installed lower than 8F.
 
Q: Cable connecting with donor antenna and repeater has been damaged.
A: Test the VSWR of that cable. The criteria of repeater project is VSWR ≤ 1.5.
 
Q: Self-osciallation occurs. The AGC alarm of the repeater will be flickering. It can be observed that the Rxlev is fluctuating, and Rxqual is deteriorated inside the coverage.
A: To solve this problem, test the isolation at first, and then set the gain to be at least 15dB lower than isolation value.
 
Q: Interference exists inside the coverage.
A: Connect spectrum analyzer with 0dBi antenna to check the signal condition inside the coverage before and after coverage. Compare the test results to see whether interference exist or not.
 
Q3: Low "make call" successful ratio inside the coverage.
Q: Donor BTS hasn't enough capacity.
A: Consult with the operator or re - select the donor signal.
 
Q: BTS noise floor is increased.
A: Test and set repeater's UL gain properly. Make sure UL noise floor reaching BTS is lower than -121dBm.
 
Q: Unbalance between uplink and downlink.
A: Reset the gain, and make sure UL gain is lower than DL gain no more than 10dB for indoor coverage, and 5dB for outdoor coverage.
 
Q: Interference exist inside the coverage.
A: Check the signal inside the coverage by spectrum analyzer.
 
Q: Self-osciallation occurs. In this condition, the Rxlev fluctuates while the Rxqual is deteriorated.
A: Test isolation, and set the gain to be 15dB lower than isolation.
 
Q4: Call drop occurs rapidly in coverage area
Q: Self-osciallation occurs
A: Test isolation, and set the gain to be 15dB lower than isolation.
 
Q: Donor signal handover frequently
A: Use the mobile phone to re-select the donor signal: make sure that primary BCCH must be 6dB higher than secondary BCCH.
 
Q: Donor BTS problem
A: Re-select the donor BTS.
 
Q5: Low handover successful rate in coverage
Q: Handover hasn't been defined between donor cell and neighboring cell.
A: Consult with operator to define handover between donor cell and neighboring cell.
 
Q: Interferences exist.
A: Check the donor signal, to see whether donor signal has been interfered or not. And then check whether interference exists inside the coverage or not.
 
Q6: Signal Leak in coverage area
Q: Unreasonable design.
A: Take the method,more antennas with lower output power , to make the coverage. In indoor coverage, make sure each antenna's input power is less than 15dBm.
 
Q: Indoor service antenna is close to the window.
A: Move the Indoor service antenna away from the coverage edge. Another solution is use the directional antenna to send the signal from outside to inside to make coverage.
 
Q: Service antenna's output power is stronger than required value.
A: Decrease the service antenna's output power to be as low as possible when coverage requirement is enough.
 
Q: Surrounding has been changed.
A: Make site survey and re-design the project.