Документация для Samsung SGH 600DY
1. General Description
1-1 GSM System
is an acronym for Global System for Mobile communications
, using TDMA for wide-area cellular
operation. The GSM system consists of the sub-systems shown;The Mobile Station (MS) talks to the Base Station System (BSS) via an RF air interface. The Base Station System(BSS) consists of Base Transceiver Station (BTS) and a Base Station Controller (BSC). The microwave linkbetween BTS and BSC is called an Abis interface. Generally one BSC controls 20 to 30 BTSs, and a MobileSwitching Center (MSC) controlling the traffic among different cells would be reported back from a number ofBSSs. A Visitor Location Register (VLR) will be allocated to one MSC to find the mobiles out of their home cellby listing them to VLR. The MSC would also be connected to the Home Location Register (HLR), theAuthentication Center (AC) and the Equipment Identity Register (EIR) So the system verify that the users andequipment are legal subscriber.
Channels used in the GSM system can be divided into two classes - Logical and Physical channel. Physicalchannels can be described in terms of their frequency and time domain characteristics. They are the actualfrequencies and timeslots the MS and BS transmits or receives on. The logical channels are mapped onto thesephysical channels logically. Any particular and instant, physical channels may be control or traffic channels,which determines the function of a physical channel at a particular point in time.
1-1-3 Airinterface of ARFCN (Absolute Radio Frequency Channel Number)
P-GSM: TX: Fl(n) = 890 + 0.2*n (1
RX: Fu(n) = Fl(n) + 45
< Fig. 1 ARFCN Diagram >