Samsung SGH-2488, Руководство по обслуживанию, Страница: 3 / 42

Samsung Electronics 1-1
1. General Description
1-1 Dualband System
1-1-1 Calls
Dual band handsets supports the E-GSM and DCS system, DCS is an acronym for Digital Cellular system, and
GSM
¨ is an acronym for Global System for Mobile communications © , using TDMA for wide-area cellular
operation. The GSM and DCS 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 interface between BTS
and BSC is called an Abis interface. Generally one BSC controls 20 to 30 BTSs, and a Mobile Switching Center
(MSC) controlling the traffic among different cells would be reported back from a number of BSSs. A Visitor
Location Register (VLR) will be allocated to one MSC to find the mobiles out of their home cell by listing them
to VLR. The MSC would also be connected to the Home Location Register (HLR), the Authentication Center
(AC) and the Equipment Identity Register (EIR) So the system verify that the users and equipment are legal
subscriber.
1-1-2 Channels
Channels used in the E-GSM and DCS system can be divided into two classes - Logical and Physical channel.
Physical channels can be described in terms of their frequency and time domain characteristics. They are the
actual frequencies and timeslots the MS and BS transmits or receives on. The logical channels are mapped onto
these physical 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)
975 1023 0 1 2 3 123 124 ... ... ... ...
880.2 MHz 890.2 MHz 914.8 MHz
DCS Rx: Fdl(n) = Ful(n) + 95MHz
< Fig. 1 ARFCN Diagram >
E-GSM: TX: Ful(n) = (0.2MHz) • n, 0
≤
n
≤
124 and
Ful(n) = (0.2MHz) • (n-1024), 975
≤
n
≤
1023
512 885
1710.2 MHz 1784.8 MHz
DCS Tx: Ful(n) = 1 (0.2MHz) • (n-511)
n = ARFCN, 512
≤
n
≤
885
512 885
1805.2 MHz 1879.8 MHz
975 1023 0 1 2 3 123 124 ... ... ... ...
925.2 MHz 935.2 MHz 959.8 MHz
E-GSM: RX: Fdl(n) = Ful(n) + 45MHz