《TD-LTE和FDD-LTE帧结构差别.doc》由会员分享，可在线阅读，更多相关《TD-LTE和FDD-LTE帧结构差别.doc（3页珍藏版）》请在三一文库上搜索。
1、TD-LTE禾口 FDD-LTE帧结构差另LTE（Long Term Evolution, 长期演进）项目是3G的演进，始于2004年3GPP的多伦多会议。LTE并非人们普遍误解的4G技术，而是3G与4G技术之间的一个过渡，是3.9G的全球标准，它改进并增强了 3G的空中接入技术，采用OFDM和MIMO作为其无线网络演进的唯一标准。在20MHz频谱带宽下能够提供下行326Mbit/s与上行86Mbit/s的峰值速率。改善了小区边缘用户的性能，提高小 区容量和降低系统延迟。4 Frame structureThroughout this specificati on, unl ess other
2、wise no ted, the size of various fields in the time doma in is expressed as a n umber of time un its Ts = 15000 2048 sec on ds.Downlink and uplink transmissions are organized into radio frames withTf =307200 Ts = 10 msdurati on. Two radio frame structures are supported:- Type 1, applicable to FDD,-
3、Type 2, applicable to TDD.4.1 Frame structure type 1Frame structure type 1 is applicable to both full duplex and half duplex FDD. Each radio frame is Tf =307200 Ts =10 ms long and consists of 20 slots of length Tslot =15360 Ts=0.5ms , numbered from 0 to 19. A subframe is defined as two consecutive s
4、lots where subframei consists of slots2i and2i 1.For FDD, 10 subframes are available for downlink transmission and 10 subframes are available for upli nk tran smissi ons in each 10 ms in terval. Upli nk and dow nli nk tra nsmissi ons are separated in the frequency domain. In half-duplex FDD operatio
5、n, the UE cannot transmit and receive at the same time while there are no such restrictions in full-duplex FDD.One radio frame, Tf = 307200 Ts = 10 msFigure 4.1-1: Frame structure type 1.4.2 Frame structure type 2Frame structure type 2 is applicable to TDD. Each radio frame of lengthT = 307200 Ts =
6、10 msconsists of two half-frames of length153600 Ts =5 ms each. Each half-frame consists of fivesubframes of length 30720 Ts =1 ms. The supported uplink-downlink configurations are listed in Table4.2-2 where, for each subframe in a radio frame,“ D” denotes the subframe is reserved for downlinktransm
7、issions,“ U' denotes the subframe is reserved for uplink transmissions and“ S” denotes asubframe with the three fields DwPTS, GP and UpPTS. The length of DwPTS and UpPTS is given byTable 4.2-1 subject to the total length of DwPTS, GP and UpPTS being equal to30720 Ts = 1ms . Eachsubframe i is def
8、ined as two slots, 2i and2i 1 of length Tslot =15360 Ts =0.5 ms in each subframe.Uplink-downlink configurations with both 5 ms and 10 ms downlink-to-uplink switch-point periodicityare supported.In case of 5 ms downlink-to-uplink switch-point periodicity, the special subframe exists in both half-fram
9、es.In case of 10 ms downlink-to-uplink switch-point periodicity, the special subframe exists in the first half-frame on ly.Subframes 0 and 5 and DwPTS are always reserved for dow nli nk tra nsmissi on. UpPTS and the subframe immediately followi ng the special subframe are always reserved for upli nk
10、 tra nsmissi on.Subframe #0DwPTS GPSubframe #2Subframe #3Subframe #51I1Subframe #71Subframe #8Subframe #4DwPTS GP SpPTSubframe #9UpPTSr1:One half-frame, 153600 Ts = 5 ms:One radio frame, Tf = 307200 Ts = 10 msOne slot, 'slot =15360 Ts30720T s*Figure 4.2-1: Frame structure type 2 (for 5 ms switch
11、-po int periodicity).Table 4.2-1: Co “figuration of special subframe (le ngths of DwPTS/GP/UpPTS).SpecialNormal cyclic prefix in downlinkExtended cyclic prefix in downlinksubframe configurationDwPTSUplNormal cyclic prefix in uplinkPTSExtended cyclic prefix in uplinkDwPTSUpNormal cyclic prefix in upl
12、inkPTSExtendedcyclic prefix in uplink06592 Ts2192 忑2560 Ts7680 Ts2192 Ts2560 Ts119760 Ts20480 Ts221952 Ts23040 Ts324144 Ts25600 -Ts426336 Ts7680 Ts4384 Ts5120 ” T56592 Ts4384 T5120 Ts20480 Ts619760 Ts23040 -Ts721952 Ts-824144 Ts-Table 4.2-2: Upli nk-dow nli nk con figurati ons.Uplink-downlink configurationDownlink-to-UplinkSwitch-point periodicitySubframe number012345678905 msDSUUUDSUUU15 msDSUUDDSUUD25 msDSUDDDSUDD310 msDSUUUDDDDD410 msDSUUDDDDDD510 msDSUDDDDDDD65 msDSUUUDSUUD5Upli nk