CDMA WLL SYSTEM IS 95

The Wireless Local Loop platform is a versatile supplement or substitute for wired local switching service. Based on IS-95 cdmaOne and 1XRTT, it possesses the quality, reliability and functionality of wired networks with the quick, cost-effective deployment associated with wireless access. It's an exceptionally powerful product for creating revenue. It is connected with mobile stations through air interfaces on one hand, and with Local Exchange(LE) through V5-interfaces on the other.

The WLL system enables complete transparency to the Local Exchange (LE) services, such as PSTN call, charging meters, reverse polarity, and variable data services.

            WLL consists of the following two primary components that are required to supply telecommunication services to subscribers:

1. BSC: The main controller of the WLL system. The BSC is connected to both the LE and radio base stations and can be located either at the LE building, another site close by, or at a remote location.

2. BTS: The radio base station that provides coverage for serviced area.

As the control part of the base station system, the BSC(base station controller) includes High-speed Interconnect Router Subsystem (HIRS), selector/vocoder bank subsystem (SVBS), call processing subsystem (CPS), base station management subsystem (BSM) and timing subsystem (TS). One end of the BSC is connected with the BTS through a CDSU, and the other end is connected with the LE through as SVICM, with the BSS system’s operation and maintenance performed at the BSC side. The BSC is mainly responsible for wireless network management, wireless resource management, BSS maintenance and management, call processing and control, MS handoff and voice coding.

The BTS(base transceiver system) is the wireless part of the BSS. It includes baseband digital subsystem (BDS), radio frequency subsystem (RFS) and timing frequency subsystem (TFS). Controlled by the BSC, the BTS realizes the wireless transmission and related control functions. Modules in the BDS are interconnected through the internal S_HIRS.