D

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[範例]
CTV(Chinese Translation Version)，中文譯稱。一段中文或英文的簡短說明:-:知識分類。====================================================
DB(Dummy Burst)，樣版burst。DB is transmitted on one frequency of the cell allocation CA, when no other bursts are to be transmitted. The frequency channel used is the same one that carries the BCCH, i.e. it is the BCCH carrier. This ensures that the BCCH transmits a burst in each time slot which enables the mobile station to perform signal power measurements of the BCCH, a procedure also known as quality monitoring.

Since the base station has to transmit in each time slot of the BCCH carrier to enable a continuous measurement of the BCCH carrier by the mobile station, a DB is transmitted in all time slots with no traffic.

Ref:
[-] Jörg Erbespächer, Hans Jörg Vogel, GSM: Switching services and protocols, Wiley 1999.

DTAP(Direct Transfer Application Part)，直接傳送應用部。類似於UMTS的NAS，在Um與Abis界面上，通訊協定載送呼叫控制(Call Control;CC)及移動管理(Mobility Management;MM)的訊息，而且它的傳送對BSS是通透性的，不做任何處理。:-:GSM網路堆疊應用層總稱。

說明：逐漸了解到DTAP是種運輸訊息的功能，它是沒有"聲音"的，所以妳找不到DTAP的專屬message。

DTAP process which allows the direct transfer of messages between individual MSs and the MSC with no interpretation of layer 3 information at the BSS.

3GPP TS 48.002 contains more detail relating to the handling of DTAP messages at the BSS, the multiplexing of themessages onto the relevant signalling channels of the radio interface, and the use of the SCCP services.

Messages received from the MS are identified as DTAP by the Protocol Discriminator Information Element asdescribed in 3GPP TS 24.008, except for Initial Layer 3 messages (see sub-clause 3.1.16).

The majority of radiointerface messages are transferred across the BSS MSC interface by the DTAP, the exceptions being messages belonging to the Radio Resource (RR) management protocol.

Ref:
[-] 何瑞光，GSM基地台系統網路界面及協定，第81期 2000.10月號
[-] (2005-09) Digital cellular telecommunications system (Phase 2+);Mobile Switching Centre - Base Station system (MSC-BSS) interface; Layer 3 specification(3GPP TS 48.008 version 6.11.0 Release 6)

070720r4版本