BISDN采用的传输模式主要有哪些？ BISDN采用的传输模式主要有高速分组交换、高速电路交换、异步传输模式ATM和光交换方式四种
求ATM（异步传输模式）相关英文文章 Asynchronous Transfer Mode(ATM)is a cell relay，packet switching network and data link layer protocol which encodes data traffic into small(53 bytes；48 bytes of data and 5 bytes of header information)fixed-sized cells.ATM provides data link layer services that run over Layer 1 links.This differs from other technologies based on packet-switched networks(such as the Internet Protocol or Ethernet)，in which variable sized packets(known as frames when referencing Layer 2)are used.ATM is a connection-oriented technology，in which a logical connection is established between the two endpoints before the actual data exchange begins.The standards for ATM were first developed in the mid 1980s.The goal was to design a single networking strategy that could transport real-time video and audio as well as image files，text and email.Two groups，the International Telecommunications Union[ITU 2004]and the ATM Forum[ATM 2004]were involved in the creation of the standards.ATM has been used primarily。
LTE的几种传输模式介绍 标签：4G(192)TD LTE(3)1.TM1，单天线端口传输：主要应用于单天线传输的场合。2.TM2，发送分集模式：适合于小区边缘信道情况比较复杂，干扰较大的情况，有时候也用于高速的情况，分集能够提供分集增益。3.TM3，开环空间分集：合适于终端（UE）高速移动的情况。4.TM4，闭环空间分集：适合于信道条件较好的场合，用于提供高的数据率传输。5.TM5，MU-MIMO传输模式：主要用来提高小区的容量。6.TM6，Rank1的传输：主要适合于小区边缘的情况。7.TM7，Port5的单流Beamforming模式：主要也是小区边缘，能够有效对抗干扰。8.TM8，双流Beamforming模式：可以用于小区边缘也可以应用于其他场景。9.TM9，传输模式9是LTE-A中新增加的一种模式，可以支持最大到8层的传输，主要为了提升数据传输速率。
