Philippines Adopts NICT’s TV White Space Database for Free Wi-Fi Project

ICTO of the Philippines is promoting a project to deploy wireless network infrastructure to provide free Wi-Fi Internet access in public places all over the country. ICTO has decided to utilize White Spaces in the TV band for wireless networking in the project particularly for underserved and unserved areas. In utilizing TV White Space, it is crucial to operate equipment carefully so as not to interfere with TV broadcastings. To avoid such interference, the White Space Database (WSDB) is needed for analyzing available TV channels at each location. Meanwhile, NICT has been developing WSDBs which satisfy the regulations of some different countries around the world for the purpose of technical evaluations, since the WSDB is regarded as one of the essential technologies to utilize the TV White Space. In response to the request from ICTO, NICT signed an MOU with ICTO in March 2015. Since then, both have engaged a series of discussions aiming to exploit NICT’s WSDB technologies for free Wi-Fi Internet access in public places.

NICT and ICTO have concluded a license agreement, providing ICTO with the WSDB developed by NICT. This WSDB stores all the TV broadcasting information and calculates the broadcasting areas, according to the geography of the Philippines. The WSDB is capable of listing up TV channels which are available for operating equipment at specified locations. In the future, it is expected that the equipment sends its location to the WSDB, the WSDB sends back available channels to the equipment, and the equipment automatically starts operation in the TV White Space. The Philippines has started terrestrial TV broadcasting services since February 2015 using the ISDB-T system developed in Japan. Accordingly, the WSDB also supports the radio propagation model for the ISDB-T system that is used in Japan to calculate TV broadcasting areas.

The White Space Database stores TV broadcasting information about the Philippines, calculates radio propagation of TV broadcastings based on terrestrial data, and draws TV broadcasting areas.

Figure 1 shows a screen shot of the White Space Database. The area marked in red indicates the calculated TV broadcasting areas on channel 31 in Cebu Island. This channel is used for TV broadcasting in the red area, however, it is available for wireless systems in the other area as TV White Space. When wireless systems operate in TV White Space, it is necessary to check whether a wireless system is in the red area or not. As there are multiple TV channels, it is required to check it throughout the all TV channels. Practically, the criteria of the TV channel availability in the database are not so simple as mentioned above, since interferences from wireless systems to TV broadcastings also need to be taken into consideration.

In deciding TV White Space availability, it takes too much time and workload when this analysis is conducted manually for all the TV channels. Consequently, NICT implements a feature to create a list of availability on each TV channel in the White Space Database. By dropping a pin on the map, setting some parameters and clicking a button, the White Space Database shows a list of channel availability at the top of the screen as shown in Figure 1. The green mark means available and the red mark means unavailable for wireless systems to use the channel.

In actual operation of the White Space Database, processes can be automated, so that an operator has no need to manually operate every time manually by operators. Location information acquired by GPS of a wireless system is sent to the White Space Database and the list of TV White Space is automatically calculated. The list is sent back to the wireless system and the channel(s) is(are) selected by the wireless system for its operation.