Problem in Allocating RBs to Adjacent Cells

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RSRQSrsPeriodicityltens-3-usersschedulersinr

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Thomas Sanders

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Jun 20, 2016, 8:08:37 AM6/20/16

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Hi all,

I am facing problems mainly in simulating an LTE network scenario. First when I simulated a single user two cells scenario everything was fine and I collected phy layer, mac layer, etc. statistics...

Now when I used two cells and multiple users distributed over their coverage area, I found that the downlink linear SINR collected through phy layer statistics is very low, due to high interference of neighbouring cell (as I checked). But even after I allocated different RBs to the two cells edge users but still the results of DL SINR is very low (due to high interference) and has no effect of the soft frequency reuse algorithm (LteFrSoftAlgorithm) that I am using to allocate different RBs to the edge users of neighbouring cells (below please check the code for it). Can any one figure out what is the reason? Also please note at each eNodeB round robin scheduler is used. Also by enabling the log of RrFfMacScheduler I can't see any difference in the allocation of resource blocks for cell users even though the RSRQ threshold (i.e. m_edgeSubBandThreshold) is increased to a significantly higher value (to enable orthogonal RBs allocation to edge users of neighbouring cells).

Second main problem is that, can any one tell me the different between the RSRQ (and RSRP) value at ue phy layer and the RSRQ value that is used to compare with the m_edgeSubBandThreshold for the corresponding reuse algorithm (let say LteFrSoftAlgorithm)? Because as I see my downlink RSRQ value calculated at ue phy (for edge users) is very small (i.e. -9.8333) but the corresponding RSRQ for edge users in frequency reuse algo (in LteFrSoftAlgorithm) is significantly high (i.e. 30 dB). Can any one tell me from where does the later comes from?

        lteHelper->SetFfrAlgorithmType ("ns3::LteFrSoftAlgorithm");
        lteHelper->SetFfrAlgorithmAttribute ("DlEdgeSubBandOffset", UintegerValue (0));
        lteHelper->SetFfrAlgorithmAttribute ("DlEdgeSubBandwidth", UintegerValue (6));
        lteHelper->SetFfrAlgorithmAttribute ("UlEdgeSubBandOffset", UintegerValue (0));
        lteHelper->SetFfrAlgorithmAttribute ("UlEdgeSubBandwidth", UintegerValue (6));
        lteHelper->SetFfrAlgorithmAttribute ("AllowCenterUeUseEdgeSubBand", BooleanValue (false));
        lteHelper->SetFfrAlgorithmAttribute ("RsrqThreshold", UintegerValue (35));
        lteHelper->SetFfrAlgorithmAttribute ("CenterPowerOffset", UintegerValue (LteRrcSap::PdschConfigDedicated::dB0));
        lteHelper->SetFfrAlgorithmAttribute ("EdgePowerOffset", UintegerValue (LteRrcSap::PdschConfigDedicated::dB3));
        macroEnbDevs.Add(lteHelper->InstallEnbDevice (macroEnbs.Get(0)));
        lteHelper->SetFfrAlgorithmAttribute ("DlEdgeSubBandOffset", UintegerValue (6));
        lteHelper->SetFfrAlgorithmAttribute ("DlEdgeSubBandwidth", UintegerValue (6)); // 6-12 RBs group need to be used by edge users of 2
        lteHelper->SetFfrAlgorithmAttribute ("UlEdgeSubBandOffset", UintegerValue (6)); //
        lteHelper->SetFfrAlgorithmAttribute ("UlEdgeSubBandwidth", UintegerValue (6));
        lteHelper->SetFfrAlgorithmAttribute ("AllowCenterUeUseEdgeSubBand", BooleanValue (false));
        lteHelper->SetFfrAlgorithmAttribute ("RsrqThreshold", UintegerValue (10));
        lteHelper->SetFfrAlgorithmAttribute ("CenterPowerOffset", UintegerValue (LteRrcSap::PdschConfigDedicated::dB0));
        lteHelper->SetFfrAlgorithmAttribute ("EdgePowerOffset", UintegerValue (LteRrcSap::PdschConfigDedicated::dB3));
        macroEnbDevs.Add(lteHelper->InstallEnbDevice (macroEnbs.Get(1)));