Can someone plz explain what it means by path balance and path imbalance....what are the parameters and KPIs to observe and understand path balancing and imbalancing (in HUAWEI/2G)..
In an optimum system, power should be well estimated in design to enable the balance between the coverage of uplink signals and the coverage of downlink signlas. If the coverage of uplink signals is wider than the coverage of downlink signals, the downlink signals at the cell edge are weak and easy to be overwhelmed by strong signals in other cells. If the coverage of downlink signals is wider than the coverage of uplink signals, the MS has to camp on the cell with strong signals; however, the uplink signals are weak and the speech quality is poor. The balance does not refer to the absolute balance. The MR on the Abis interface can be used to check whether the coverage of uplink signals and the coverage of downlink signals are in balance.
The MR received by the BSC contains the uplink receive level and the downlink receive level. Subtract the uplink receive level and the parameter X from the downlink receive level. The results in dB are graded from levels 1 to 11, and the number of MRs of each level is calculated. Table 1 lists the mapping between the balance level and the receive level.
Table 1 Mapping between the uplink-downlink balance level and the receive levelLevel of the Balance Between the Uplink and the Downlink
Downlink Receive Level - Uplink Receive Level - Parameter X 1=≤-15 dB 2=-14 dB, -13 dB, -12 dB, -11 dB, -10 dB 3=-9 dB, -8 dB, -7 dB, -6 dB 4=-5 dB, -4 dB, -3 dB 5=-2 dB, -1 dB, 0 dB 6=0 dB 7=1 dB, 2 dB 8=3 dB, 4 dB, 5 dB 9=6 dB, 7 dB, 8 dB, 9 dB 10=10 dB, 11 dB, 12 dB, 13 dB, 14 dB 11=15 dB, 16 dB, 17 dB, 18 dB, 19 dB, 20 dB
Can someone plz explain what it means by path balance and path imbalance....what are the parameters and KPIs to observe and understand path balancing and imbalancing (in HUAWEI/2G)..
Thanks in advance...
BR
Guess
Path balance simply means that signal losses in DL direction should be equal to that in the UL direction (or at least to have 3dB difference due to diversity ) i.e provides an indication of the RF link between the MS and BTS. Usually when you have very big difference in path balance distribution first step is to check the equipment - TRX calibration, malfunction, poor cabling installation, present of interferences in the RF environment, some UEs also can distort path balance and etc. there are really many reasons and you have to identify where the problem is.
path balance = path losses difference = UL path loss - DL path loss.
(Amplifiers external to the cabinet, mast mount pre-amps, power amps excreta, are not included in the calculation and will have a larger impact on the PB number)
By looking into tx_balance_lev 1 to 11 how does this statistics suppose to look like for me to say this site cell is having poor path balance. please explain.
to add on the troubleshooting of poor path balance causes
1. if the problem exists on one radio, you can try to swap with another radio of the same site! and check if the problem followed the rtf or stayed with the radio.If the problem is on multiple radios then focus on number 2 below
2.Is there poor VSWR ,if return loss is more than 6dBm?, try to focus on cabinet/antenna cabling,the enviroment,backplane, bad duplexer..
Last edited by leelio; 2010-11-27 at 09:37 PMReason: edit
By looking into tx_balance_lev 1 to 11 how does this statistics suppose to look like for me to say this site cell is having poor path balance. please explain.
thanks in advance
I really don't understand Huawei 2G and their statistics but obviously if you have 5-7 (or even 4-8) is OK and for everything above/below i.e 1-4/8-11 you should pay attention. There are some vendors that even tollerate 10dB difference. The best is to check what Huawei recommendation is.
By looking into tx_balance_lev 1 to 11 how does this statistics suppose to look like for me to say this site cell is having poor path balance. please explain.
In an optimum system, power should be well estimated in design to enable the balance between the coverage of uplink signals and the coverage of downlink signlas. If the coverage of uplink signals is wider than the coverage of downlink signals, the downlink signals at the cell edge are weak and easy to be overwhelmed by strong signals in other cells. If the coverage of downlink signals is wider than the coverage of uplink signals, the MS has to camp on the cell with strong signals; however, the uplink signals are weak and the speech quality is poor. The balance does not refer to the absolute balance. The MR on the Abis interface can be used to check whether the coverage of uplink signals and the coverage of downlink signals are in balance.
The MR received by the BSC contains the uplink receive level and the downlink receive level. Subtract the uplink receive level and the parameter X from the downlink receive level. The results in dB are graded from levels 1 to 11, and the number of MRs of each level is calculated. Table 1 lists the mapping between the balance level and the receive level.
Table 1 Mapping between the uplink-downlink balance level and the receive levelLevel of the Balance Between the Uplink and the Downlink
Downlink Receive Level - Uplink Receive Level - Parameter X 1=≤-15 dB 2=-14 dB, -13 dB, -12 dB, -11 dB, -10 dB 3=-9 dB, -8 dB, -7 dB, -6 dB 4=-5 dB, -4 dB, -3 dB 5=-2 dB, -1 dB, 0 dB 6=0 dB 7=1 dB, 2 dB 8=3 dB, 4 dB, 5 dB 9=6 dB, 7 dB, 8 dB, 9 dB 10=10 dB, 11 dB, 12 dB, 13 dB, 14 dB 11=15 dB, 16 dB, 17 dB, 18 dB, 19 dB, 20 dB
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Path Balance/Imbalance
Originally Posted by guess.who
Reputation: 491
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