Praise for Fundamentals of WiMAX

416 Chapter 12 • System-Level Performance of WiMAXTable 12.4 Average Throughput per BS Site for Handheld and Desktop Device withBand AMC Subcarrier Permutation in DL and ULScenarioHandheld DeviceDesktop DeviceDL (Mbps) UL (Mbps) DL (Mbps) UL (Mbps)(1,1,3) reuse in Ped B 131.47 21.13 146.77 23.59(1,3,3) reuse in Ped B 57.09 9.18 57.08 9.17(1,1,3) reuse in Ped A 139.88 22.48 150.26 24.15(1,3,3) reuse in Ped A 57.62 9.26 57.86 9.30Table 12.5 Fifth and Tenth Percentile Data Rate for Basic ConfigurationScenarioHandheld DeviceDesktop Device5% (Mbps) 10% (Mbps) 5% (Mbps) 10% (Mbps)(1,1,3) reuse in Ped B 0.025 0.075 0.146 0.252(1,3,3) reuse in Ped B 0.449 0.525 0.480 0.550(1,1,3) reuse in Ped A 0.025 0.075 0.036 0.220(1,3,3) reuse in Ped A 0.351 0.490 0.406 0.517The DL throughput shown in this section is significantly higher than the UL throughout,since the number of OFDM symbols (28) allocated for the DL subframe is larger than the numberof OFDM symbols (9) allocated for the UL subframe. Varying the number of symbols to be usedfor DL and UL subframes makes it possible to control the ratio of the DL and UL throughputs.Figure 12.7 shows the throughput performance for the PUSC and the band AMC subcarrierpermutations. Since no precoding or beamforming is used, depending on the multipath channelband AMC provides an improvement of only 14 percent to 18 percent in the overall sectorthroughput compared to PUSC.Figure 12.8 shows the throughput performance of the round-robin and proportional-fairness(PF) scheduling algorithms. The sector throughout improves by approximately 25 percent byusing a proportional fairness (PF) scheduler compared to a round-robin (RR) scheduler, due tothe ability of the PF scheduler to exploit multiuser diversity to a certain extent. Table 12.6 summarizesthe DL throughput for the PF and RR schedulers in various multipath environments.12.3.2 System-Level Results of Enhanced ConfigurationsIn this section, we estimate the impact on system capacity of a WIMAX network of some of theMIMO features that are part of the IEEE 802.16e-2005 standard. See Chapter 8 for a detaileddescription of the various open- and closed-loop MIMO schemes.The average per sector throughput for the basic and various enhanced configurations isshown in Figure 12.9 and Figure 12.10. Based on these results, one can conclude that both