tailieunhanh - CDMA: Access and Switching P3

Switched CDMA Networks Overview Code Division Multiple Access (CDMA) has been widely accepted and used for wireless access in terrestrial and satellite applications. These applications often require switching of the CDMA traffic channels in order to establish connectivity between end users. In existing terrestrial wireless networks, while CDMA is used for access, connectivity and routing is achieved via the Public Switched Telephone Network (PSTN). It is often desirable, however, that access and switching is performed within the same network in many applications. An example of such an application is the Satellite Switched CDMA (SS/CDMA) system presented in. | CDMA Access and Switching For Terrestrial and Satellite Networks Diakoumis Gerakoulis Evaggelos Geraniotis Copyright 2001 John Wiley Sons Ltd ISBNs 0-471-49184-5 Hardback 0-470-84169-9 Electronic 3 Switched CDMA Networks Overview Code Division Multiple Access CDMA has been widely accepted and used for wireless access in terrestrial and satellite applications. These applications often require switching of the DMAA traffic channels in order to establish conncctivity between end users. In existing tetrestlral wtrelees nctworks tvliie- CIM1A ss iiewl for acesss connectivity and routing is cciiii e-dd via hie Pbbfic twite lied helehCohe Nctwork PSTN . It is often desirable however that access and switching ss performed withm the same network in many applications. An example of such an application is the Satellite Switched CDMA SS CDMA system presented in 1 . The SS CDMA network is comprised of a multibeam satellite and a large population of ground users as illustrated in Figure . Ground users within each beam access the satellite by CDMA. The satellite is equipped with an on-board switch for routing mter- r intra-beam calls. The SS CDMA network is described in detail in Section . Similar satellite systems based on TDMA called Satellite Switched TDMA SS TDMA are presented elsewhere 2 3 and 4 . As in the satellite example CDMA switchingmay also be used in terrestrial applications. These applications include wireless and cable networks that have CDMA as their access method. An example of such a network called Base-station Switched CDMA BS CDMA is illustrated in Figure . The BS CDMA is comprised of a CDMA exchange node connected to a number of Radio Distribution Points RDPs via distribution lines which carry the CDMA signal. The exchange node in this case provides the switchingcapability for establishingconnectivity between the wireless users. This wireless network may be used for fixed or mobile services. Similar systems based on TDMA have also been .