When Telkom switches off ADSL…
What if LTE can’t meet the “off-grid” demand?
A recent article quoted Telkom CEO Sipho Maseko saying Telkom recently developed a roadmap concerning the proactive migration of customers to newer infrastructure. “We are hoping that in the next five years, we would have exited copper entirely,” Maseko said. This means if it is successful with its plan, Telkom’s operational network would primarily comprise mobile, LTE and fibre technology.
At the same press event, Maseko continued to say that the company’s fixed-broadband subscriber base – which includes ADSL and FTTH customers – decreased by 13.8% to 847 650 over the period and added that Telkom’s fixed LTE customer base now represents more than its historical peak ADSL user base. Interesting statistics and indeed a fine achievement from a technology growth and future-ready strategy perspective.
What will it take to replace ADSL with LTE?
From various press comments, we understand that Telkom’s aim is not merely to replace its ageing ADSL infrastructure and service the current subscriber base. Rather, Telkom is striving to implement an upgraded service and enable a wider digital economy through increasing the access footprint and providing broadband services to all.
When considering this objective and evaluating LTE as a primary technology to replace ADSL, some interesting basic questions arise. How many additional LTE towers will be needed to provide the required signal coverage? Will all LTE users receive the same broadband speeds regardless of distance from the tower and signal strength? What frequency spectrum will be needed to meet the demand to replace the ADSL subscriber base?
While most of these questions can only be precisely answered through detailed engineering modelling and network prediction algorithms, we can achieve a sound understanding by considering some fundamentals. Since signal range, or network coverage and connection data rates are very much the key considerations for any wireless broadband access market, we will review these as a reference.
Data connection speeds on cellular and LTE networks are dependent on the signal strength as well as the congestion on the network. That is, the total number of users that are active within the tower range.
Lab tests conducted by Cellular Insights shows the data throughput significantly degrades as the signal weakens when moving further away from the tower. At signal levels of -105dBm (this is a weak to poor signal level), 50% of the theoretical data rates can be expected.
The communication distance from user devices to network towers depends on many aspects. Cell towers are more likely to work on a maximum range of about 16km, because the protocol used for cellphone calls become unreliable further than this distance. In rural areas, the tower's range usually goes from 3.2km up to 9.6km. In suburban areas, the tower's range usually goes from 1.1km to 3.2km, and in an urban area, the tower's range is usually 100 metres to 500 metres.
This bias of LTE networks to be more short-range and more applicable to high density areas is evident from Telkom’s current LTE coverage maps, shown below. Note that this focus area and target market is mostly the same area and target market as the current metropolitan fibre network services. From this perspective, LTE and fibre will both service the high-density urban areas and not the traditional ADSL market, which was reached via the copper networks.
Will LTE replace ADSL?
LTE can certainly be an effective broadband technology and can be used very effectively to connect broadband subscribers.
But whether LTE will replace ADSL is a much more complex question, and one that is essentially about network capital investment, large-scale deployments of LTE tower infrastructure, and extensive fibre backhaul networks. All of this is required to service low density subscriber geographical areas. The business case for LTE as a profitable option to connect subscribers outside the high-density metros is yet to be seen in actual deployments.
Satellite as an immediate alternative
While LTE has a difficult business case to balance and will need significant investor capital, the recently developed high throughput satellite (HTS) networks such as the Twoobii are ready for service. With performance and price points on par with LTE, HTS satellite offers attractive options for reliable off-grid business connectivity.