The 21st Meeting of the APT Wireless Group (AWG-21)
3 – 7 April 2017, Bangkok, Thailand
27 March 2017
Introduction of practical use example of FWS
using the VHF band broadband radio system toward the proposal
for a draft outline for a new APT report on applications of fixed
wireless systems to resolve digital divides
At the AWG-20 held in Bangkok, September 2016, the new APT Report on fixed wireless systems in APT region was completed. Its contents are mainly focused on enabling technologies for fixed wireless systems. To facilitate application of fixed wireless systems, information of practical usage scenarios may be useful.
Based on the above, this document was wrote to show some practical cases of bridging digital divide with the fixed wireless systems. We hope this could help countries of APT to better understand the signification of fixed wireless systems and promote the utilization of fixed wireless systems.
In APT countries, some rural areas face difficulties in providing broadband internet access via optical fibers because of their geographical conditions such as mountains, islands, etc. Fixed wireless systems are effective solutions for digital divides.
Digital divide is becoming a worldwide concern in 21st century. Especially in the developing countries, digital divide is thought to be a reason of poverty. ICT is considered to be an important social infrastructure next to water, electricity and gas. Poor region will stay poor if digital divide continues. In recent years, with the progress of social ICT, the gap caused by the digital divide has been getting wider.
By connecting the rural area with internet, services that are contributing to live could be available to the rural residents. For example, e-health services including the tele-medicine system, health management application and medical consultation can be available for improving the health of the nation and protecting lives of the nation from superstition and other dangerous. Also, e-education services such as web service and tele-education can be introduced to increase the education chances and improve the education quality. Moreover, by expanding internet in the nationwide, young generation is able to establish new industry in anywhere they want, and governments are able to maintain the national sovereignty via ICT infrastructure.
Compared to optical fiber, the fixed wireless radio system with superiorities such as low cost and easy construction is considered to be a more effective solution to the digital divide. To study variety of cases of the fixed wireless radio system is believed to help the effort on bridging the digital divide.
Japan proposes to initiate to develop a new APT report on applications of fixed wireless systems to resolve digital divides such as the system shown in the Annex 1. Annex 2 will become the basis for the structure of a draft new APT report, and Annex 3 will be the workplan of this report.
ANNEX 1 Introduction of practical use example of FWS using the VHF band broadband radio system
ANNEX 2 Draft outline for a new APT report on applications of fixed wireless systems to resolve digital divides
ANNEX 3 Draft workplan of the new report
Introduction of practical use example of FWS using the VHF band broadband radio system
Outline of VHF/UHF band radio system
The network construction in digital divide areas is not so easy considering factors like geography, cost and so on. To overcome these problems, the technology of VHF/UHF band radio systems are considered to be very effective solutions.
Fig.1 shows the network connection image with VHF/UHF band radio systems in digital divide areas. With the feature of frequencies, VHF/UHF band radio systems are suitable for communicating over obstacles such as the mountainous area.
Fig.1: Network connection image with VHF/UHF band radio system in digital divide area
To bridging the digital divide, there are many solutions such as the optical fiber, wireless LAN (Wi-Fi) and Satellite Link. However, most of these solutions require high cost and have many requirements on the construction environment, which make them difficult to be adopted commonly. Comparing to the above solutions, VHF/UHF band radio system has many superiorities such as:
lower interference risk,
superior VHF/UHF long-range propagation / nice diffraction (non- line-of-sight communication is available)
effective utilization of vacant radio resource, and so on.
Fig. 2: Typical Usage of VHF/UHF broadband radio system in digital divide area
Fig.2 shows the Typical Usage of VHF/UHF broadband radio system in digital divide areas. Generally, with the nationwide IP networks, residents in the urban area of a country can access to the internet easily, while for the residents in the rural area, due to factors such as economy and geography, internet accessing is still impossible. VHF/UHF broadband technology is considered to be useful for expand internet service to such kind of remote rural area. Utilizing VHF/UHF broadband radio, services such as internet surfing, e-mail, social network service (SNS), public service, disaster information would be available to the rural area residents.
Practical use example: Internet access for school in Nepali mountainous area
To support the recovery concerning the massive earthquake hit Nepal in April 2015, Hitachi Kokusai Electric donated a VHF-Band broadband radio system for network connection in remote rural area to E-Networking Research and Development (ENRD), which is a not-for-profit organization (NPO) in Nepal. Also, in November 2016, Hitachi Kokusai Electric dispatched engineers to Nepal under the support of APT-J Nepal Project to provide a train on the donated radio system to local engineers from Nepal Wireless(NPO).
ENRD and Nepal Wireless have been devoting to connecting schools in the remote rural areas of Nepal with broadband network for many years. Last year, they constructed a broadband network in one of the rural school with the VHF-Band broadband radio system donated by Hitachi Kokusai Electric.
A license was required for using the corresponding frequency and Nepal Wireless applied for it from the Ministry of Information and Communications Technology (MoICT) of Nepal. As a result, Nepal Wireless was provided permission to use some VHF and TVWS band by Nepal Telecommunication Authority (NTA) with the recommendation from MoICT of Nepal in May 2016. The allowable frequency bands are shown in Fig. 3.
Accordingly, they can use 192.5 MHz to 202.5 MHz (10 MHz) in VHF band and 560 MHz to 578 MHz (18 MHz) in TVWS（TV White Space） band for rural broadband network.
VHF：192.5 MHz to 202.5 MHz (10 MHz)
TVWS：560 MHz to 578 MHz (18 MHz)
100 200300400500600 [MHz]
Fig 3: Spectrum for rural broadband in Nepal
The frequency available for Hitachi’s VHF-Band broadband radio system is from 192.5MHz to 202.5MHz as shown in Fig. 3.
The appearance and specifications of the radio device for VHF-Band broadband radio system are shown in Fig.4 and Table 1, respectively (This product is designed and manufactured with the technology transfer from National Institute of Information and Communications Technology (NICT)). There are three schemes for the data-ratio of uplink to downlink, which are 12 to 35, 21 to 26 and 38 to 9. For Nepali case, the uplink to downlink data ratio was set as 12 to 35 by considering the priority of internet access.
Sites to be connected were selected from the candidate list provided by Nepal Wireless. With a comprehensive analyzation based on the link budget calculation and surrounding terrain, Nagarkot and Jholunge were determined to be the sites for base station and rural station, respectively. Fig.5 shows the terrain and altitude of the sites.
Fig 5: Sites (Terrain and Altitude)
As shown in Fig.5, terrain configuration between Nagarkot and Jholunge was so severe that an in line-of-sight communication was impossible. However, it was considered to be effective by utilizing the properties such as reflection and sneak of mountainous terrain.
Fig.6, Fig.7 and Fig.8 show the scenes of base station site and rural station site. As shown in Fig.8, instead of a point against terrain construction, the antenna direction of the rural station was set at the point where a higher received power was available.
Fig 6: Base Station（Nagarkot）
Fig 7: Rural Station（Jholunge）
Fig 8: Antenna direction setting at Jholunge
Fig.9 shows the statistics of radio connection obtaining from a maintenance PC. By setting the modulation and coding scheme (MCS) as QPSK 1/2, the throughput of uplink and downlink was obtained at 2Mbps and 400kbps, respectively, which enabled the network access. And right side of Fig.9 shows the constellation of demodulated QPSK signal.
In this Nepali case, the network construction including the antenna installation for each site was accomplished in around 3 hours by 3 people.
Fig 9: Statistics of radio connection
The Nepali case verified that the network construction could be realized without costing too much time even in the non-line-of-sight environment such as the mountainous area with the VHF-Band broadband radio system.
Different from Wi-Fi technology, by utilizing the VHF-Band’s superiority of propagation property, the prospect between antennas is no longer required. Accordingly, a relay station in a steep mountain for assuring the prospect is not necessary, which enables the maintenance and operation to be much more comfortable.
Moreover, to realize the goal including achieving a broadband internet user penetration rate of 30% by 2018, expanding the broadband connection to 70% in villages and providing at least 1Mbps broadband connection to 20% of public secondary schools shown in the National Broadband Policy disclosed by MoICT of Nepal in 2014, VHF-Band broadband radio system is considered undoubtedly to be an effective solution to overcome the limitations of mountainous terrain in Nepal.
In the near future, by bridging the digital divide, improvement of nation’s life quality and new employment opportunities could be expected.
Draft outline for a new APT report on applications of fixed wireless systems
to resolve digital divides
3. Vocabulary of terms
5. Current status of digital divides in APT countries