A report titled WILLCOM XGP Field Test: Over 11Mbps Under Favorable Conditions was published on Nikkei Communications’ July 1 issuance. We hereby extracted the key part from the report to introduce the advantages of XGP with some comment on it. Interested party of the original report can purchase the magazine from http://ec.nikkeibp.co.jp/item/backno/CC0537.html

 

 

WILLCOM has started leasing out data card for WILLCOM Core XGP, or next generation PHS network under trial run since late June. The magazine obtained a card of the kind and carried out appraisal on its effective speed in Tokyo. As a result, the magazine recorded the best effective rate for downlink at 11Mbps. It also measured the similar rate for downlink and uplink in XGP system under favorable conditions. These results proved XGP a system with performance beyond ordinary expectation.

 

To be prepared for XGP commercial service planed on October 2009, WILLCOM is providing area restricted service from April 22 on. The terminals on lease during the period are GX000IN made by NetIndex and GX000N by NEC Infrontia. Both are terminal in PC card shape. After confirming that there is no obvious functional difference between the two types of terminals, the magazine chose GX000IN for the appraisal test.

 

Regarding the test operation, XGP’s theoretical best rate for both uplink and downlink is 20Mbps (see Chart 1). How much the effective speed can draw close to with this theoretical value, is the point of the evaluation this time. To compare with, the magazine carried out measurement for two other terminals. One of them is UQ WiMax for mobile WiMax service started in July 1^st by UQ Communications. The other is an HSPA (High Speed Packet Access) terminal by for E-mobile service.

 

Theoretical best rate is 40Mbps at downlink and 10Mbps at uplink for UQ WiMax, while 7.2Mbps at downlink and 5.8Mbps at uplink for E-mobile’s HSPA terminal D23HW.

 

 

This time, the magazine conducted measurement on ①Effective Speed ②Round Trip Time（RTT）. To obtain a reliable result, the magazine chose scattered spots to carry out the measurement of ①effective speed. The three testing spots are chosen as East Entrance of Ikebukuro Station, Southern Entrance of Shinjuku Station, and Maruno-Utsi Entrance of Tokyo Station. Considering the business function, the magazine has chosen window-side seats in station’s coffee shop, where radio signals are comparatively easy to be picked up, to conduct the measurement. 

 

Speed was measured by transmitting a file of 1Mb between a PC connected to a terminal and an FTP server. Measurement for each terminal is carried out at three times. Average was adopted as the result for appraisal. PC which was connected to home FTTH circuit with uplink /downlink rate of 100Mbps was used in the FTP server.

 

Test result was shown in Image 1. At all the three spots in Tokyo, XGP demonstrated better performance than other systems.

 

Looking at downlink rate, at Ikebukuro, where all systems managed to receive stable radio signal, XGP was recorded an average speed of 5.6Mbps. Comparing to that, UQ WiMax scored 3.85Mbps and HSPA of E-mobile reached 4.1Mbps. At other measuring spots, XGP gained better outcome than other systems too.

 

Although not recorded in Image 1, there was one time that the effective speed of over 11Mbps was recorded for XGP at Minato District, Tokyo, where WILLCOM headquarter is close and radio signal is strong.

 

Looking at uplink rate, one could tell obvious advantage of XGP. At Ikebukuro, XGP recorded an average rate at 4.09Mbps. Comparing to that, UQ WiMax got 830Mbps only and HSPA of E-mobile 860Kbps. At other spots, XGP all kept an uplink rate of over 3Mbps.

 

This proved that XGP’s uplink rate is almost unchanged to its downlink rate. We can say that the symmetrical transmission rate for downlink and uplink is a unique and favorable feature of XGP.

 

Chart 1　Equipment Used in Measurement
PC used in measurement are Let’s Note CF－R8 （carrying Windows Vista Business）by Panasonic.

 

 

Despite, transmission rate is influenced by the amount of users. It must be mentioned that the test operation for limited amount of users gave the method a favorable position.

 

Image 1　Measurement of Effective Speed of Three Methods
1Mb file was downloaded/uploaded from Internet through FTP server. Recorded result was the average from 3 times’ operation. Measurement was conducted in the afternoon of July 19.

Image 2　Measurement of RRT and Its Quiver
RTT from sending ping command to connected to www.nikkeibp.co.jp measured. Recorded are 4 times’ average, maximum and minimum.

Despite of having favorable record on transmission speed, XGP, which is still introducing equipment to expand coverage, faces rigorous market condition. Besides, indoor communication, which was a weak point of UQ WiMax, is less problematic as long as the connection is guaranteed at window-side seat. It is commonly felt that XGP shall have a higher indoor connection rate than UQ WiMax.

 

(by translator: MAC and PHY design of XGP enabled it to make best use of Adaptive Antenna System, hence, we believe that the indoor penetration rate of an XGP system is absolutely advantageous than WiMax.)