Tham khảo tài liệu 'quality of service and resource allocation in wimaxfig part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Multi Radio Resource Management over WiMAX-WiFi Heterogeneous Networks Performance Investigation 141 User position behavior WiFi only WiMAX only Smooth Tx Qu 1 Still near the PoA 2 Still 30 m far from the PoA 3 Moving away at 1 m s starting from the PoA 4 Near the PoA for half sim. then 30 m far away Table 1. TCP layer average throughput. Single user 1 WiFi access point and 1 WiMAX base station co-located. 10 seconds simulated. order of few dozens of meters . the coverage range of a WiFi where both RATS are available for this reason the x-axis of Fig. 5 ranges from 0 to 30 meters. The different curves of Fig. 5 refer in particular to the traffic-management strategy above described and for comparison to the cases of a single WiFi RAT and of a single WiMAX RAT. Of course when considering the case of a single WiMAX RAT the throughput perceived by an user located in the region of interest is always at the maximum achievable level as shown by the flat curve in Fig. 5. As expected on the contrary the throughput provided by WiFi in the same range of distances rapidly decreases for increasing distances. The most important result reported in Fig. 5 however is related to the upper curve that refers to the previously described traffic-management strategy when applied in the considered heterogeneous WiFi-WiMAX network. As can be immediately observed the throughput provided by this strategy is about the sum of those provided by each single RAT which proves the effectiveness of the proposed traffic-management strategy. The impact of the user s position and mobility has also been investigated the results are reported in Table 1 and are related to four different conditions 1. the user stands still near the PoA optimal signal reception 2. the user stands still at 30 m from the access PoA optimal WiMAX signal but medium quality WiFi signal 3. the user moves away from the PoA at a speed of 1 m s low mobility 4.
