high band is in general easier to optimize and therefore high band can provide better spectral efficiency. The higher the carrier frequency the less is the PUSCH SINR decrease while the uplink data volume per cell increases as shown in Figure 13.16. Also the more the bandwidth available the more uplink data volume can be delivered with certain PUSCH SINR level. Based on Figure 13.16 the 20 MHz bandwidth allocation provides more than double uplink data volume per cell compared to the high band 10 MHz bandwidth allocation at the same PUSCH SINR level (with PUSCH SINR 5 to 10 dB). As can be seen from Figure 13.16 there are several low band cells (grey circle) which are suffering from excessive uplink inter-cell interference. These cells are having massive overshooting coverage area and therefore PUSCH SINR performance is poor regardless of uplink data volume. Capacity Optimization Low band (10 MHz) High band (10 MHz) High band (20 MHz) Log. (low band (10 MHz)) Log. (high band (10 MHz)) Log. (high band (20 MHz)) y = 1.7381n(x) + 19.873 y = -2.658ln(x) + 22.918 y = -2.0861n(x) + 14.336 Average UL data volume per cell (MB) Figure 13.16 Average PUSCH SINR per cell as a function of average uplink data volume per cell. Highest loaded cells included with 15-minute statistics samples The actual spectral efficiency in terms of bit/s/Hz per cell can be calculated based on the active cell throughput statistics and allocated bandwidth per cell. Figure 13.17 shows example per different bands and bandwidths. As can be seen from Figure 13.17 the 3GPP-simulated spectral efficiency of 0.74 bit/s/Hz [3] per cell for 100% load can be met and exceeded provided that the PUSCH SINR is better than 6 dB. It should be also noted that this high spectral efficiency can be achieved by low band and high band with 10 and 20 MHz bandwidths. The 3GPP simulations for spectral efficiency are using full buffer traffic model which means that each cell is having 100% UL PRB utilization at the same time. The own cell UL PRB utilization and its neighbour