Wireless Local Loop (WLL) or Radio Local Loop (RLL) is the wireless realization of the last mile, the wireless subscriber connection between the local exchange and the house connection. Wireless Local Loop is an alternative wherever new network operators implement the subscriber access and where the costs for wired cabling
would be considerably higher due to the settlement. The basis of a WLL network is the WLL radio cell. Here, a WLL radio cell divided into sectors is broadcast by radio from a base station. The area of such a WLL cell is between 8 sq km and 30 sq km and can be divided into four or eight sectors. The radio transmission takes place as a point-to-multipoint connection (P2MP) and, depending on the frequency used, must be licensed by the regulatory authority RegTP. The frequency ranges subject to licensing are 2.5 GHz, 3.5 GHz and 26 GHz and offer transmission rates of 2 Mbit/s to 3 Mbit/s in the lower frequency ranges and 30 Mbit/s to 40 Mbit/s in the upper range. The connections
from the base station to the end customer are star-shaped, with several end customers connected simultaneously to one base station. The range of the antennas is several kilometers, so that several base stations are required to open up a region
The various WLL technologiesIngeneral, all radio technologies such as the DCS-1800 network, GSM or the C-network
aresuitable for implementing the Wireless Local Loop. Some technologies are not suitable because of their low subscriber density, poor voice quality and low transmission speed
.WLL technologies are divided into small cell networks, cellular mobile radio systems, microwave radio systems and satellite systems. Small cell networks are based on the advanced DECT standard forcordless telephony
. Here, the base station, which is operated at theexchange
, supplies several end customers.In cellular mobile radio systems such as GSM, the transmission channels can be used to connect stationary end devices. In radio relay systems, a distinction is made between point-to-point and point-to-multipoint links, the latter of which can serve multiple end users. In addition to radio-based transmission, there are also systems that use optical directional radio with laser beams. In terms of satellite systems, only those using LEO satell
itesand MEO satellites (low and medium earth orbit) are suitable, because only these enable direct communication with the end devices at low transmission power
. Wireless Local Loop (WLL) is a thing of the past.
Most of the projects were already discontinued in 2002 and 2003 due to the investment involved, as the providers needed their own completely new network structures for base station communications if they did not want to be dependent on Deutsche Telekom. WiMAX can be seen as an alternative radio technology that can also be used in the access area.