Each TAWA system essentially includes one BSC, multiple BSs and a combination of different subscriber terminals (WS, MWS). RBS can be used to increase the coverage area of a BS and BSD can be employed to increase the distance between BSC and BS. The number of BSs and subscriber terminals supported by the system depends on the configuration. The BSC acts as a switch or a Remote Switching Unit, connected to E1 lines using R2-MF or V5.2 protocols. Individual BS can be connected to the BSC using three pairs of twisted copper wires. The power required for the BS operation is fed on the same cables from the BSC. Each isolated BS can serve about 50 subscribers at 0.1 Erlang per subscriber providing a grade of service 1 %. The range supported is 5 kms in the line-of-sight situation when BSs are mounted on roof-tops or towers.

A group of BS can be connected to the BSC, on fibre or radio medium by employing BSD. Each BSD can support four BSs. BSD has to be locally powered and BSD intern powers the BS.

To serve subscribers in rural areas, it is possible to program the Wallset in a special mode which would allow it to be used up to 10 Kms from a BS with a line-of-sight link. Further, using Relay Base Station, the coverage area of a TAWA WLL system can be extended to 25 Kms to serve subscribers in sparsely populated areas.
     
The TAWA system is designed to provide a cost-effective wireless high-quality voice and data connection in dense urban as well as sparse rural areas. It is composed of :  

 


BSC (Base Station Controller)

Performs switching, system control and interfaces TAWA WLL system to telecom network.

  


BS (Base Station)

Provides wireless access in an area and supports twelve simultaneous full duplex channels.
 
 


WS (WallSet)

A wireless fixed terminal, connected to any standard telephone, modem or fax machine and/or to a personal computer.

  


WS-IP (WallSet-IP)

It ensures the same services of voice as the WS, but it allows in more an Internet access without recourse to modem.
     


MWS
(Multi-WallSet )

Wireless fixed terminal, providing four independent (telephone, fax, modem) connection in a building.

  


BSD
(Base Station Distributor)

Connects four remotely-located BSs to the BSC using an E1 link, radio or fibre.
     


RBS
(Relay Base Station)

A relay device to extend the BS wireless coverage to 25 kms.

  


NMS
(Network Manager System)

Manages multiple BSCs and their associated BS, wallset, multiwallset, BSDs and RBS.
     


RAS
(Remote Access Server)

RAS allows INTERNET connectivity for TAWA subscribers.

  


Parc Technologique des Communications, Route de Raoued - B.P. 16 - Ariana - Tunisia / Phone (+216) 71 857 738 / Fax (+216) 71 857 740