| Optimization & troubleshooting (CDMA) |
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| 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. |
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| 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. |
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| Q: Repeater's gain setting is low. |
| A: Check and set the repeater's gain through OMT. |
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| Q: Repeater's frequency has been changed. |
| A: Check and set repeater's working frequency through OMT. |
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| Q: Cable or passive components of the coverage system are damaged. |
| A: Check VSWR of the coverage system. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| Q: Interference exist inside the coverage. |
| A: Check the signal inside the coverage by spectrum analyzer. |
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| 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. |
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| 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. |
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| Q: There's problem with donor BTS. |
| A: Reselect the donor BTS. |
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| 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. |
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| 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. |
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| 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. |
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| Q: Surrounding has been changed. |
| A: Make site survey and re-design the project. |
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| Optimization & troubleshooting (GSM) |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| 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. |
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| Q: Donor BTS problem |
| A: Re-select the donor BTS. |
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| 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. |
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| 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. |
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| 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. |
