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- 2014 (3) (remove)
Keywords
- IEEE 802.11n (1)
- Long-distance (1)
- MIMO (1)
- Wireless back-haul (1)
This work describes extensions to the well-known Distributed Coordination Function (DCF) model to account for IEEE802.11n point-to-point links. The developed extensions cover adaptions to the throughput and delay estimation for this type of link as well peculiarities of hardware and implementations within the Linux Kernel. Instead of using simulations, the approach was extensively verified on real-world deployments at various link distances. Additionally, trials were conducted to optimize the CWmin values and the number of retries to maximize throughput and minimize delay. The results of this work can be used to estimate the properties of long-distance 802.11 links beforehand, allowing the network to be planned more accurately.
The lack of affordable broadband Internet connectivity in rural areas, especially in emerging regions, is seen as a major barrier for access to knowledge, education or government services. In order to reduce the costs of back-hauling in rural regions, often without access to a stable power grid, alternative solutions are required to provide high-bandwidth back-hauling at minimal power consumption to allow solar-powered operation. In this paper, we show that cost-effective low-power IEEE802.11n (MIMO) hardware together with a single cross-polarized antenna can be a viable solution to the problem. Our study shows that up to 200 Mbps of actual throughput can be achieved over distances larger than 10 km while the power consumption of a typical forwarding node is well below 10 Watts (http://wiback.org/repeater) - suitable for a cost-effective solar-powered operation. Through theoretical analysis and extensive measurements we show that such a low-cost setup can be used to establish reliable long-distance links providing high-bandwidth connectivity at low latencies and consequently providing the capacity demanded by today’s services - everywhere. Exploiting these findings we are in the process of extending existing fiber-based infrastructures in rural Africa with our Wireless Back-Haul (WiBACK) architecture.
TV white spaces (TVWS), are seen as a key technology to enable the efficient use of scarce sub-GHz spectrum allowing for applications that may have a huge impact on internet penetration in rural parts of Africa. We first give an overview on TVWS, its use cases and highlight possible challenges against its uptake. Then we describe our carrier-grade wireless back-hauling solution (WiBACK) and discuss its capability for working with a geolocation database ensuring zero interference with licensed users.
