6.4.3 Test Result

6.4.3        Test Result

            Wi-Fi range for outdoors is 95 Meters with data rate transfer 54 Mbps which is 54 megabits per second where when the data size to be transferred is 54MB. One byte is equal to eight bits. This means 54 Mbps which is 54 megabits per second is equal to 6.75 MBps which is 6.75 megabytes per second. The range and speed of the synchronization operation is shown in Figure 6.4. The Wi-Fi range and data rate transfer depends on the wireless access point specifications and the size of data being transferred. The D-Link DWL-2100AP used as a Wi-Fi access point for this offline email system where the effective range is shown in Table 5.1.

            Online server computer storage is Samsung HD754JJ with sequential reads speed is 89.30 MBps and writes speed is 130.3 MBps. Infomediary device storage is Kingston Micro SD with sequential reads speed is 20.04 MBps and writes speed is 2.03 MBps. Offline server computer storage is Western Digital WD5000BEVT with sequential reads speed is 54.42 MBps and writes speed is 28.79 MBps. The read and write speeds of Online server computer storage, informediary device storage and offline server computer result is produced by CrystalDiskMark version 3.0.2. The comparison of transfer rate, read speed and write speed is summarized in Table 6.3.

No	Device	Read Speed	Write Speed
1	Wi-Fi Access Point: Offline server computer (D-Link DWL-2100AP) Online server computer (Riger DB 108-WL Wireless ADSL Modem 2/2+)	Outdoors operation transfer rate is 6.75 MBps with effective range 95 meters
2	Online server computer storage (Samsung HD754JJ)	89.30 MBps	130.3 MBps
3	Infomediary device storage (Kingston Micro SD)	20.04 MBps	2.03 MBps
4	Offline server computer storage (Western Digital WD5000BEVT)	54.42 MBps	28.79 MBps

Table 6.3 Transfer rate, read speed and write speed comparisons

            The transfer rate of data during database synchronization is limited by infomediary device storage write speed which is 2.03 MBps. This means that when the size of data to be transferred is 54MB with the transfer rate is 2.03 MBps and range between server computer and infomediary device is 95 meter, the speed of infomediary device movement through the Wi-Fi range of the server computer is:

       (Network range/Size of data) x transfer rate = (95 meter/54 MB) x 2.03 MBps = 3.57 m/s

Equation 6.1 Infomediary device movement speed

            Based on calculation, the maximum recommended speed of infomediary device movement through the Wi-Fi range of the server computer is 3.57 m/s equal to 12.85 km/hr or less. The data synchronization is not completed if the infomediary device movement exceeds this speed. It is also recommended if the infomediary device is staying for about five to ten minutes at the server computer. This will allow for database synchronization to complete successfully.

Figure 6.4: Range and speed for mail data synchronization