**3.2 Bandwidth requirement based on measurement result**

Bandwidth occupation by Mix traffic from smartphones and iPads can be seen in Figure 10 and Figure 11 respectively.

Fig. 10. Femtocell mix traffic bandwidth from 4 smartphones, measured in xDSL (layer 2) and application (layer 7)

The summary of statistical properties for individual traffic and mixed traffic accessed by both smartphone and iPad are shown in Table 4 and Table 5 respectively.

Since both DL and UL traffic follow lognormal distribution, maximum value is used so that all traffic can traverse smoothly. According to Table 4, we can see that the bandwidth required for a femtocell depends on the type of traffics. In downlink side it requires about 602 kbps to perfectly handle mix traffic from 4 smartphones while in uplink is about 175 kbps. The uplink traffic in smartphone contains voice AMR (12.2kbps) so ideally the bandwidth should be preserved above 84.8 kbps.

150 Mobile Networks

repeated several times, i.e. 30 times effectively, but only the best 3 retries with similar

The measurement process was divided into two phases. Firstly, we captured individual bandwidth consumed by http, ftp, voice (AMR) and youtube streaming. The service was accessed from a smartphone connected to a FAP. Secondly, we observed the throughput for four simultaneous voice calls and mix traffic (HTTP, FTP, youtube, voice) from four

We repeated the similar observation for iPad. Since iPad is designed to access packet data only, hence voice AMR call cannot be tested. We replaced the voice call with facebook. We understood that most iPad users frequently download new applications, audio-video podcasts, mp3 music, ebooks from iTunes or Apple Store. For similarity with the observation in smartphone, we used ftp traffic from 4shared.com to download bigger file size compared to the one from smartphone. We also used the same page from detik.com. While from smartphone, mobile page version was displayed; in the iPad, full web page was

Bandwidth occupation by Mix traffic from smartphones and iPads can be seen in Figure 10

a) downlink b) uplink Fig. 10. Femtocell mix traffic bandwidth from 4 smartphones, measured in xDSL (layer 2)

The summary of statistical properties for individual traffic and mixed traffic accessed by

Since both DL and UL traffic follow lognormal distribution, maximum value is used so that all traffic can traverse smoothly. According to Table 4, we can see that the bandwidth required for a femtocell depends on the type of traffics. In downlink side it requires about 602 kbps to perfectly handle mix traffic from 4 smartphones while in uplink is about 175 kbps. The uplink traffic in smartphone contains voice AMR (12.2kbps) so ideally the

both smartphone and iPad are shown in Table 4 and Table 5 respectively.

bandwidth should be preserved above 84.8 kbps.

statistical properties will be shown.

different smartphone at the same time.

and Figure 11 respectively.

and application (layer 7)

displayed, hence the consumed bandwidth is different.

**3.2 Bandwidth requirement based on measurement result** 

Fig. 11. Femocell mix traffic bandwidth from 4 iPads, measured in xDSL (layer 2) and application (layer 7)

In case of iPad being used as shown in Table 5, the downlink bandwidth consumption is about 857 kbps and the uplink is about 632 kbps. The uplink traffic for iPad is higher than smartphone because mix traffic mainly used by youtube. However as can be seen from Figure 11 peak throughput of 632 kbps is occurred only small portion compared to overall throughput shape, the rest of throughput is below 400 kbps.


Table 4. Statistical properties of individual and mix traffic in smartphone case

So far we have derived the bandwidth requirement for femtocell by monitoring the throughput from Femtocell NMS.


Femtocell Performance Over Non-SLA xDSL Access Network 153

higher bandwidth consumption, the bandwidth requires for smartphone case logically will also be supported. For femtocell we use generated traffix mix from Spirent Test Centre (STC) and Cisco Telepresence Service. This is important since we need a reference service performance to be monitored in the presence of other traffic from other FUEs as well as the PC. In this case video conference is used since it has several performance metrics including throughput, jitter and packet loss for both video and audio quality. In order to approach femtocell BR obtained from bandwidth requirement observation which uses real traffic, we generated mix traffic from STC is made as close as possible to the iPad mix traffic. The comparison between generated traffic and real iPad mixed traffic can be seen in Figure 12.

Fig. 12. The comparison between generated traffic and iPad mix traffic

**4.2 Performance degradation due to background traffic in access** 

BR obtained from scenario 1.

loss < 3%, jitter < 40ms).

The test scenario is divided into two sub scenarios. The first sub-scenario is to obtain the femtocell performance without background traffic. While in the bandwidth requirement measurement (scenario 1) we set xDSL profile only to 20 Mbps; in this sub-scenario we set the line bandwidth to 20 Mbps, 1 Mbps, and 800 kbps. In each line profile we observed the video-audio performance. It will give a performance reference as well as verification to the

In the second sub-scenario we activate the traffic from PC. We then analized the performance of video conference (packet loss, jitter) with the existence of background traffic. In this case we used reference performance of xDSL set to 1 Mbps without background and compare the new video performance in the presence of background from PC. We increased the bandwidth profile step by step until the video performance below the threshold (packet

Table 6 shows the video conference performance without PC background. When the xDSL bandwidth profile set to 800 Kbps or equal to BR for iPad, the video quality for iPad is maintained below the threshold; the packet loss below 3% and the jitter far below than 40 ms. By giving 20% more bandwidth to 1 Mbps it will give additional space to anticipate other header and load during busy hours and also it will give better performance for real time


Table 5. Statistical properties of individual and mix traffic in iPad case
