g8-7-8-9.htm

介绍移动通信gsm原理的书籍

            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的连接可以是直达链路，也可</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; mso-spacerun: yes">&nbsp; 
            </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">由汇接局转接。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">VLR</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">查出被叫客户的位置区识别码</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(LAI)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">之后，</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">将寻呼消息发送给位置区内所有的</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">BTS</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，由这些</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">BTS</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">通过无线路径上的寻呼信道</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(PCH)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">发送寻呼消息，在整个位置区覆盖范围内进行广播寻呼。守候的空闲</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MS</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接收到此寻呼消息，识别出其</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">IMSI</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">码后，发送应答响应。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">&nbsp;</SPAN></FONT></P>
            <P class=MsoNormal 
            style="TEXT-INDENT: 21.75pt; LINE-HEIGHT: 150%"><FONT 
            color=#000066><SPAN lang=EN-US 
            style="FONT-SIZE: 12pt"><O:P></O:P></SPAN></FONT></P>
            <P class=MsoNormal 
            style="TEXT-INDENT: 21.75pt; LINE-HEIGHT: 150%"><FONT 
            color=#000066><B><SPAN lang=EN-US style="FONT-SIZE: 12pt"><A 
            name="7.9  释  放">8.9<SPAN style="mso-spacerun: yes">&nbsp; 
            </SPAN></A></SPAN><A name="7.9  释  放"><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">释</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt; mso-spacerun: yes">&nbsp; 
            </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">放</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><O:P> 
            </O:P></SPAN></A></B></FONT></P>
            <P class=MsoNormal 
            style="TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><FONT 
            color=#000066><SPAN lang=EN-US 
            style="FONT-SIZE: 12pt">GSM</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">系统使用的呼叫释放方法与其它通信网使用的呼叫释放方法基本相同，通信的双方都可以随时终止通信。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><O:P> </O:P></SPAN></FONT></P>
            <P class=MsoNormal 
            style="TEXT-INDENT: 24pt; LINE-HEIGHT: 150%; mso-char-indent-count: 2.0; mso-char-indent-size: 12.0pt"><FONT 
            color=#000066><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">GSM</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">实施第一阶段的规范中，对释放过程可以简化成只用两条消息，如释放由移动台发起，客户按“结束</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(END)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">”键发“拆除”</SPAN><SPAN 
            style="FONT-SIZE: 12pt"> </SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">消息，</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">收到后就发送“释放”消息。若是网路端</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">(</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">PSTN)</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">发起的释放过程，</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">收到“释放”消息就向移动台发出“拆线”消息。在</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">GSM</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">实施的第一阶段，客户从拆线到释放这段时间内不再交换信令数据，于是释放过程可以简化成只用两条消息。</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt"><O:P> </O:P></SPAN></FONT></P>
            <P class=MsoNormal 
            style="TEXT-INDENT: 21.75pt; LINE-HEIGHT: 150%"><FONT 
            color=#000066><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">用三条消息这种更复杂的释放过程只是用于将来在客户拆线到释放这段时间交换必要的信令。</SPAN></FONT></P>
            <P class=MsoNormal 
            style="TEXT-INDENT: 21.75pt; LINE-HEIGHT: 150%"><FONT 
            color=#000066><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如果是一次</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">ISDN</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的通信，</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">ISUP</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">上送出“释放”消息，通知对方通信终止，端到端的连接到此结束。但至此呼叫并末完全释放，</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">到移动台的本地链路仍然保持还需执行一些辅助任务，例如向移动台发送收费指示等。当</SPAN><SPAN 
            lang=EN-US style="FONT-SIZE: 12pt">MSC</SPAN><SPAN 
            style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">认为没有理由再保持与移动台之间的链路时，就向移动台送“拆除”消息，移动台返回“释放完成”消息，这时所有低层链路才释放，移动台回到空闲状态。</SPAN></FONT></P>
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