[转帖]1G?2G?2.5G?3G?

tony0415

<p class="MsoNormal" align="center" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center;"><b><span style="FONT-SIZE: 11pt; FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">什么是</span></b><font face="Times New Roman"><chmetcnv wst="on" unitname="g" sourcevalue="1" hasspace="False" negative="False" numbertype="1" tcsc="0"><b><span lang="EN-US" style="FONT-SIZE: 11pt;">1G</span></b></chmetcnv><b><span lang="EN-US" style="FONT-SIZE: 11pt;">/<chmetcnv wst="on" unitname="g" sourcevalue="2" hasspace="False" negative="False" numbertype="1" tcsc="0">2G</chmetcnv>/<chmetcnv wst="on" unitname="g" sourcevalue="2.5" hasspace="False" negative="False" numbertype="1" tcsc="0">2.5G</chmetcnv>/<chmetcnv wst="on" unitname="g" sourcevalue="3" hasspace="False" negative="False" numbertype="1" tcsc="0">3G</chmetcnv>? GSM? GPRS?<p></p></span></b></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman">&nbsp;</font></p></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 15pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><chmetcnv wst="on" unitname="g" sourcevalue="1" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">1G</span></chmetcnv><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">（<span lang="EN-US">first generation</span>）表示第一代移动通讯技术。如现在以淘汰的模拟移动网。<span lang="EN-US"><p></p></span></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 15pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><chmetcnv wst="on" unitname="g" sourcevalue="2" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">2G</span></chmetcnv><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">（<span lang="EN-US">second generation</span>）表示第二代移动通讯技术。 代表为<span lang="EN-US"> GSM </span>。以数字语音传输技术为核心。<span lang="EN-US"><p></p></span></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 15pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><chmetcnv wst="on" unitname="g" sourcevalue="2.5" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">2.5G</span></chmetcnv><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">
                </span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">是基于<chmetcnv wst="on" unitname="g" sourcevalue="2" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">2G</span></chmetcnv>与<span lang="EN-US">
                                <chmetcnv wst="on" unitname="g" sourcevalue="3" hasspace="False" negative="False" numbertype="1" tcsc="0">3G</chmetcnv>
                        </span>之间的过渡类型。代表为<span lang="EN-US"> GPRS </span>。比<chmetcnv wst="on" unitname="g" sourcevalue="2" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">2G</span></chmetcnv>在速度、带宽上有所提高。可使现有<span lang="EN-US">GSM </span>网络 轻易地实现与高速数据分组的简便接入。<span lang="EN-US">
                                <p></p></span></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 15pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><chmetcnv wst="on" unitname="g" sourcevalue="3" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">3G</span></chmetcnv><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">（<span lang="EN-US">third generation</span>）表示第三代移动通讯技术。面向高速、 宽带 数据传输。国际 电信 联盟（<span lang="EN-US"> ITU </span>）称其为<span lang="EN-US">IMT-2000</span>（<span lang="EN-US">International Mobile Telecom-munication</span>）。最高可提供<span lang="EN-US">2Mbp/s</span>的数据传输速率。主流技术为<span lang="EN-US"> CDMA </span>技术代表有<span lang="EN-US"> WCDMA </span>（欧，日）、<span lang="EN-US"> CDMA2000 </span>（美）和<span lang="EN-US">TD</span>－<span lang="EN-US">SCDMA</span>（中）。<span lang="EN-US"><p></p></span></span></p><p class="MsoNormal" align="left" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 15pt; TEXT-ALIGN: left; mso-pagination: widow-orphan; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto;"><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">什么是<span lang="EN-US">GSM</span>？<span lang="EN-US">
                                <br/></span>全球移动通讯系统（<span lang="EN-US">Global system for Mobile communications</span>）的英文缩写。<chmetcnv wst="on" unitname="g" sourcevalue="2" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">2G</span></chmetcnv>的主流技术，数据速率为<span lang="EN-US">9.6kb/s</span>。<span lang="EN-US">
                                <p></p></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: 宋体;">什么是<span lang="EN-US">GPRS</span>？<span lang="EN-US"><br/></span>通用分组无线业务（<span lang="EN-US">General Packet Radio Service</span>）的英文缩写。是一种基于<span lang="EN-US">GSM</span>系统的无线 分组交换 技术。是<chmetcnv wst="on" unitname="g" sourcevalue="2.5" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">2.5G</span></chmetcnv>的主流技术。理论最高数据速率为<span lang="EN-US">171.2kb/s</span>。<span lang="EN-US"><p></p></span></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">参考资料：</span><span lang="EN-US"><font face="Times New Roman">http://www.ldci.com.cn/docc/news_detail.asp?id=79&amp;sortid=6</font></span></p>