. The AP is connected to the CPE which is connected via the air to a WiMAX base station. The AP and CPE both have different QoS priorities for delivering video. Table 4.2 proposes a mapping mechanism that maps the QoS classes of WiMAX to WiFi QoS classes. This mechanism can be installed via software upgrade in the necessary entities (BS, AP, CPEs) of both the networks. When the CPE detects that is connected to the WiFi AP it needs to change its WiMAX QoS priorities to the one proposed in Table 4.2. Similarly, when the AP detects that it is hooked up to a WiMAX CPE it needs to change its WiFi QoS priorities to the one proposed in Table 4.3 After switching to Table 4.2 priorities the correct QoS can be delivered to the end-user (Figure 4.13). The mechanism defines new priorities for the different classes of traffic. Some classes are combined into one traffic category since those are applied to the same application. For example, nrtPS (WiMAX QoS priority 3) applies to MPEG video SO does the video (priority 4) of WiFi. For such cases, the new QoS mechanism combines the two but similar QoS classes into one and assigns priority # 14. 4.4.2 WiMAX Femtocells WiMAX operates at 2.3, 2.5, and 3.5 GHz frequency ranges, which are higher than cellular operating frequencies, and thus expected to have poorer indoor coverage than traditional cellular technologies that operate in 800/900/2100 MHz bands. WiMAX Femtocells, though not endorsed by neither by IEEE 802.16 working group nor by WiMAX Forum, can solve the problem of indoor coverage. WIMAX QoS Mechanism VolP Packets VolP Packets (UGS QoS) VolP Packets (UGS QoS) (UGS QoS) Access ((o)) Controller WiMAX CPE Base Station WiFiAP Ethernet Cable IP backbone WiFi QoS Access Mechanism Controller IP backbone Outdoor CPE Ethernet Base Station (wall mounted) Cable WiFi/WiMAX hybrid Network WiMAX Network Figure 4.12 Successful delivery of QoS in a WiMAX/WiFi hybrid network NewQoS Machanism Enabled VolP Packets (UGS QoS) VolP Packets VolP Packets (UGS QoS) (UGS QoS) Access ((o)) Controll