Television White Spaces (TVWS) are set to deliver faster and wider-reaching broadband connectivity in rural areas of South Africa.
A large number of the country’s population currently resides in rural locations, where the need for effective communication technologies remains high.
The rollout of expensive broadband technologies like fibre, LTE, and 5G is is difficult to justify in areas which are rife with poverty.
The need therefore exists for solutions that can provide widespread connectivity at a relatively low cost.
According to CSIR principal researchers Dr Albert Lysko and Prof Luzango Mfupe, TVWS is one of the technologies that could help overcome this challenge.
TVWS are the gaps within the lower frequency spectrum range between the 470-694MHz (excluding 606-614MHz) on which analogue TV broadcasts are currently transmitted.
These gaps can be observed in the white noise or snow between analogue channels on a TV.
With the right equipment, these gaps can then be used for data transfers, just like other spectrum used for mobile and Wi-Fi connectivity from the 1GHz band and above.
The CSIR team has trialled the technology and developed a geolocation spectrum database (GLSD) which will help ICASA manage the allocation of spectrum to TVWS service providers without causing interference to TV broadcasting.
Lysko said that there were plenty of these gaps of spectrum available for use, particularly in rural areas. He provided the following graph and map to illustrate this availability during a recent presentation in a webinar.
Performance and suitability
Lysko explained that TVWS offers wide coverage and good propagation – penetrating well through objects like vegetation and walls.
The CSIR’s tests showed that while using the spectrum it was possible to achieve a download speed of 54Mbps over 4km with a direct line of sight.
At around 431m away from the antenna, the speed increased to 87Mbps with a direct line of sight, while 42Mbps was recorded with a restricted line of sight at 717m away.
Typically, TVWS bands allowed for data transfer speeds between 20Mbps and 50Mbps.
The CSIR said that TVWS was ideally suited for areas with population densities of between 18 to 100 people, while it could also be utilised in conjunction with satellite and 1GHz+ cellular technologies like Wi-Fi for locations of between 5 to 500 people.
This means that up to 41% of the country’s population could benefit from TVWS networks, as shown in the table and maps below.
Costs and coverage
According to Lysko, the typical pricing per TVWS base station ranges between $3,500 (R54,920) and $4,500 (R70,610), while a CPE is priced at $460 (R7,220) to $600 (R9,417).
The number of client devices which can be supported by a single base station may vary by brand/model – from eight to 50.
While the CSIR said this made TVWS devices much more affordable than LTE equipment, it submitted it was more expensive than Wi-Fi infrastructure.
However, Lysko outlined several key advantages over Wi-Fi networks which could account for this cost, including:
- Around eight-times better propagation.
- Several times wider area coverage – Fewer nodes needed to cover an area, which means lower total cost.
- More flexibility for selecting sites.
- More robust to theft as the equipment must be linked to the GLSD to work.
Overall, this meant that it was likely that TVWS offered a lower network cost than 5.8GHz+ Wi-Fi.
Lysko added that TVWS standards have also been established in South Africa, while equipment is already available from multiple manufacturers – such as Adaptrum, Carlson, Redline, and 6Harmonics.