lancing via exit/entry point tuning for non-equal priority layers Inter-layer Mobility Optimization Load balancing between 2.6G/20 MHz and 800M/10 MHz LTE layer DL traffic volume (GB) 2.6G DL traffic volume (GB) 800M DL PRB utilization 2.6G DL PRB utilization 800M Day (relative) Figure 15.18 Example of intra-sector traffic balancing via static exit/entry mobility threshold tuning, from lower carrier frequency to higher The principle shown in Figure 15.17 is illustrated by the example in Figure 15.18 where the high-priority layer is 20 MHz LTE2600 and the lower priority layer is 10 MHz LTE800. In this case the 2.6 GHz higher priority layer is almost unutilized. The LTE2600 layer RSRP exit and entry points are decreased by 8 dB on day 46 while keeping the hysteresis as a constant at 4 dB. This results in the LTE2600 layer absorbing more traffic. While the carried traffic and PRB utilization of the LTE2600 layer increase by a factor of almost three, the LTE2600 utilization at daily level still remains low relative to layer capacity. This demonstrates the expected outcome that the tuning of the static mobility thresholds has somewhat limited traffic steering capability which is strongly dependent on the UE distribution and the path loss difference between layers. In terms of service level the lower exit point also decreases the minimum UE throughput offered by the higher priority layer. Figure 15.19 shows an example where the high-priority layer is 20 MHz LTE2600 and the lower priority layer is 10 MHz LTE800. In the example the LTE2600 layer is congested and the 800 MHz layer is underutilized in terms of served traffic volume. The LTE2600 layer exit point and LTE800 entry point are modified on day 17, in order to increase footprint of the 800 MHz layer. The change results in increased traffic on the LTE800 layer. However, closer analysis reveals that in this case most of the traffic volume increase is due to traffic obtained from other sites while the LTE2600 layer still remains highly loaded. This exemplifies anothe