adewijaya
2011-07-28, 08:01 AM
Signal Fluctuation during a Call
1) Cell Handover during a Call
Cell handover keeps continuity of a call when a MS moves from one cell to another. If the target cell is far from the source one, signal fluctuation may arise.
2) Interference during a Call
I. When interference arises during a call, the uplink and downlink level is high, but the signal is of poor quality (high BER). Cell handover is caused in this case. If the signal strength of the target cell and that of the source cell are greatly different, the signal fluctuates.
II. If hardware faults are cleared but the voice quality of the TRX is still poor, it is an indication that the sampled frequency point encounters interference. Suppress the interference.
3) Improper Parameter Configuration during a Call
Signal fluctuation during a call may be influenced by some parameters, such as uplink power control threshold, frequency hopping related parameters and so on.
Instances:
I. When the value of the uplink power control threshold is too low, and the uplink has interference, the quality of reception is low. The handover happens for the sake of quality recovery. If the signal strength of the target cell and that of the source cell are greatly different, the signal fluctuates.
II. When the network adopts frequency hopping mode, HSN and MAIO are used to select a traffic channel. If the HSN and MAIO of different channels within the range of the frequency reuse cluster are set the same, great interference may arise inside the cell or between cells that have the same frequency hopping group. In this situation, handover happens for the sake of quality recovery. If the signal strength of the target cell and that of the source cell are greatly different, the signal fluctuates.
4) Network Fault during a Call
A network fault refers to a hardware fault. For example, an uplink receiver is brown down, or transmission interrupts. A network fault can cause a call drop.
1) Cell Handover during a Call
Cell handover keeps continuity of a call when a MS moves from one cell to another. If the target cell is far from the source one, signal fluctuation may arise.
2) Interference during a Call
I. When interference arises during a call, the uplink and downlink level is high, but the signal is of poor quality (high BER). Cell handover is caused in this case. If the signal strength of the target cell and that of the source cell are greatly different, the signal fluctuates.
II. If hardware faults are cleared but the voice quality of the TRX is still poor, it is an indication that the sampled frequency point encounters interference. Suppress the interference.
3) Improper Parameter Configuration during a Call
Signal fluctuation during a call may be influenced by some parameters, such as uplink power control threshold, frequency hopping related parameters and so on.
Instances:
I. When the value of the uplink power control threshold is too low, and the uplink has interference, the quality of reception is low. The handover happens for the sake of quality recovery. If the signal strength of the target cell and that of the source cell are greatly different, the signal fluctuates.
II. When the network adopts frequency hopping mode, HSN and MAIO are used to select a traffic channel. If the HSN and MAIO of different channels within the range of the frequency reuse cluster are set the same, great interference may arise inside the cell or between cells that have the same frequency hopping group. In this situation, handover happens for the sake of quality recovery. If the signal strength of the target cell and that of the source cell are greatly different, the signal fluctuates.
4) Network Fault during a Call
A network fault refers to a hardware fault. For example, an uplink receiver is brown down, or transmission interrupts. A network fault can cause a call drop.