TD、WCDMA和CDMA2000天线系统覆盖比较

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<p>&nbsp;&nbsp;&nbsp; TD-SCDMA系统中使用了多端口阵列天线，通过调整不同的权值来实现扇区覆盖与波束扫描，业务波束的扫描实现了用户的跟踪。图1给出天线在跟踪过程中天线波束扫描的效果。</p><p>&nbsp;&nbsp;&nbsp; 而WCDMA和CDMA2000使用的天线与2G移动通信系统中实用的天线相同，都是固定波束天线，图2给出TD-SCDMA采用扇区天线阵覆盖与WCDMA、CDMA2000采用常规波束宽度65度增益18dBi定向天线以及波束宽度120度增益16dBi定向天线覆盖区域比较。</p><p><img src="http://www.cww.net.cn/upLoadFile/2007/7/12/2007712154214734.jpg" border="1" alt=""/></p><p>&nbsp;&nbsp;&nbsp; 图1：TD-SCDMA系统天线波束跟踪过程</p><p><img src="http://www.cww.net.cn/upLoadFile/2007/7/12/2007712154215580.jpg" border="1" alt=""/></p><p>&nbsp;&nbsp;&nbsp; 图2：三种系统覆盖比较</p><p>&nbsp;&nbsp;&nbsp; TD-SCDMA智能天线与WCDMA、CDMA2000传统天线场强覆盖比较有以下结果：</p><p>&nbsp;&nbsp;&nbsp; 1、无论在扇区的中心方向还是扇区的边缘方向，TD－SCDMA系统天线比传统天线信号场强：高5～8dB（在发射功率相等的情况下）；或要达到同样信号唱片，基站的发射功率小3～6倍。</p><p>&nbsp;&nbsp;&nbsp; 2、传输距离：远77％～150％。</p><p>&nbsp;&nbsp;&nbsp; 3、基站数目：少2/3～5/6。</p><p>&nbsp;&nbsp;&nbsp; 在多用户情况下，TD-SCDMA上下链路平衡，而WCDMA、CDMA2000上下链路不平衡。</p><p>&nbsp;&nbsp;&nbsp; 如果考虑到智能天线基站接收灵敏度与信号/噪干正相关，不仅信号增益高，而且噪声、干扰、多径衰落由于工作波束的变窄而减小，实际通信情况可能还比图3（A）中显示的更乐观。</p><p><img src="http://www.cww.net.cn/upLoadFile/2007/7/12/2007712154216621.jpg" border="1" alt=""/></p><p>&nbsp;&nbsp;&nbsp; 图3：三种系统比较</p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/" target="_blank"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">文章出处</span></span><font face="Times New Roman">:</font></a><a href="http://bbs.tong-xin.com/" target="_blank"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">通信广角</span></span></a></span><span lang="EN-US" style="FONT-SIZE: 12pt; COLOR: black; FONT-FAMILY: 宋体;"><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/" target="_blank"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">参考资料</span></span><font face="Times New Roman">:</font></a><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-2514-5-2.html" target="_blank"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">第三代移动通信系统原理篇</span></span></a><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-1000-1-1.html" target="_blank"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp;</font></span><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">第三代移动通信系统原理篇</span></span></a><font face="Times New Roman"><span style="mso-spacerun: yes;">&nbsp; </span><p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-2479-1-2.html" target="_blank"><font face="Times New Roman">CDMA</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">数字移动通信系统的软切换技术</span></span></a><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-63-1-5.html" target="_blank"><font face="Times New Roman">CDMA</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">及第三代移动通信系统专题讲座</span></span></a><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-2435-1-2.html" target="_blank"><font face="Times New Roman">3G</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">无线基本原理培训</span></span></a><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-317-1-4.html" target="_blank"><font face="Times New Roman">CDMA</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">通信经典讲义</span></span></a><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-2462-1-2.html" target="_blank"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">第三代移动通信中上、下行链路业务量不等时频带资源的分配</span></span></a><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-2171-1-3.html" target="_blank"><font face="Times New Roman">CDMA</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">无线</span></span><font face="Times New Roman">(RF)</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">网络规划</span></span></a><font face="Times New Roman">
                        </font></span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;"><p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-486-1-4.html" target="_blank"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">软件无线电<span lang="EN-US">技术在</span></span></span><font face="Times New Roman">3G</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">和</span></span><font face="Times New Roman">4G</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">中的应用</span></span></a><font face="Times New Roman">
                                <p></p></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 17.6pt;"><span lang="EN-US" style="COLOR: black;"><a href="http://bbs.tong-xin.com/thread-81-1-4.html" target="_blank"><font face="Times New Roman">SCDMA</font><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;mso-hansi-font-family:&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><span lang="EN-US">的关键技术与无线接入技术的走势</span></span></a></span><span lang="EN-US" style="COLOR: black; FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体;"><p></p></span></p><p><p><br/></p></p>