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<TD borderColor=#6699ff><FONT
size=2>您的位置：技术园地>技术讲座-GSM蜂窝移动通信系统 </FONT></TD></TR>
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<DIV align=center><FONT size=4><B><FONT color=#000099>第三讲
GSM关键技术</FONT></B></FONT></DIV></TD></TR>
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<P> </P>
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<P class=MsoNormal><B><SPAN
style="FONT-SIZE: 15pt; COLOR: navy; mso-bidi-font-size: 10.0pt; mso-hansi-font-family: Times New Roman"><SPAN
lang=EN-US><O:P></O:P></SPAN></SPAN></B><SPAN lang=EN-US
style="FONT-SIZE: 10pt; mso-hansi-font-family: Times New Roman; mso-spacerun: yes">
</SPAN><SPAN lang=EN-US
style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes"> </SPAN>3.1 <B>工作频段的分配<O:P>
</O:P></B></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><SPAN
lang=EN-US style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes"> </SPAN><B>（1）工作频段<O:P>
</O:P></B></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><SPAN
lang=EN-US style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes"> </SPAN><FONT
face=楷体_GB2312
color=#000066>见图3-1。我国陆地公用蜂窝数字移动通信网GSM通信系统采用900MHz频段：<O:P>
</O:P></FONT></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><FONT
face=楷体_GB2312 color=#000066><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes">
</SPAN>905～915（移动台发、基站收）<O:P> </O:P></SPAN></FONT></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><FONT
face=楷体_GB2312 color=#000066><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes">
</SPAN>950～960（基站发、移动台收）<O:P> </O:P></SPAN></FONT></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><FONT
face=楷体_GB2312 color=#000066><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes">
</SPAN>随着业务的发展，可视需要向下扩展，或向1.8GHz频段的DCSI800过渡，即1800MHz频段：<O:P>
</O:P></SPAN></FONT></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><FONT
face=楷体_GB2312 color=#000066><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes">
</SPAN>1710～1785（移动台发、基站收）<O:P> </O:P></SPAN></FONT></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><FONT
face=楷体_GB2312 color=#000066> <SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman">1805～1880（基站发、移动台收）<O:P>
</O:P></SPAN></FONT><FONT face=楷体_GB2312><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"><O:P></O:P></SPAN></FONT><FONT
face=楷体_GB2312><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"><O:P></O:P></SPAN></FONT><SPAN
lang=EN-US
style="mso-hansi-font-family: Times New Roman"><O:P></O:P></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-INDENT: 21pt; TEXT-ALIGN: justify"
align=center><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman">
<IMG height=207 src="g3-1.files/g3-1.H3.gif" width=393
v:shapes="_x0000_i1025"></SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt; TEXT-ALIGN: center"
align=center><SPAN
style="mso-hansi-font-family: Times New Roman"><FONT face=楷体_GB2312
color=#000066>图<SPAN lang=EN-US>3-1<SPAN
style="mso-spacerun: yes">
</SPAN>我国陆地蜂窝移动体系系统频段分配图</SPAN></FONT></SPAN><FONT face=楷体_GB2312
color=#000066><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"> </SPAN></FONT><SPAN
lang=EN-US style="mso-hansi-font-family: Times New Roman"><O:P>
</O:P></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><SPAN
lang=EN-US style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes"> </SPAN><B>（2）频道间隔<O:P>
</O:P></B></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><SPAN
lang=EN-US style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes"> </SPAN><FONT
face=楷体_GB2312
color=#000066>相邻两频道间隔为200kHz，每个频道采用时分多址接入（TDMA）方式，分为8个时隙，即8个信道（全速率）。每信道占用带宽200kHz／8=25kHz，同模拟网TACS制式每个信道占用的频率带宽。从这点看二者具有同样的频谱利用率。<O:P>
</O:P></FONT></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-INDENT: 21pt; TEXT-ALIGN: justify"><FONT
face=楷体_GB2312 color=#000066><SPAN
style="mso-hansi-font-family: Times New Roman">将来<SPAN
lang=EN-US>GSM采用半速率话音编码后，每个频道可容纳16个半速率信道。</SPAN></SPAN></FONT><SPAN
lang=EN-US
style="mso-hansi-font-family: Times New Roman"> <O:P>
</O:P></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify"><SPAN
lang=EN-US style="mso-hansi-font-family: Times New Roman"><SPAN
style="mso-spacerun: yes"> </SPAN><B>（3）频道配置<O:P>
</O:P></B></SPAN></P>
<P class=MsoNormal
style="TEXT-JUSTIFY: inter-ideograph; TEXT-INDENT: 21pt; TEXT-ALIGN: justify"><SPAN
style="mso-hansi-font-family: Times New Roman"><FONT face=楷体_GB2312
color=#000066>采用等间隔频道配置方法，频道序号为<SPAN
lang=EN-US>76～124，共49个频点（见图3-2）。频道序号和频点标称中心频率的关系为：<O:P>
</O:P></SPAN></FONT></SPAN></P>
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face=楷体_GB2312 color=#000066><SPAN lang=EN-US
style="mso-hansi-font-family: Times New Roman"> <IMG height=137
src="g3-1.files/g3-1.H4.gif" width=383
v:shapes="_x0000_i1026"></SPAN></FONT></P>
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