lte概述(編輯修改稿)
2025-08-18 09:47 本頁面
【文章內(nèi)容簡介】 8 144 2048 144 2048 144 2048 (x Ts) 1slot = 15360 1 0 2 3 4 5 6 1 0 2 3 4 5 6 0 1 2 3 4 5 6 PSCH SSCH PBCH PDCCH Reference Signal 1 frame 1 subframe 1 slot 0 1 8 2 3 4 5 6 7 9 10 11 12 19 13 14 15 16 17 18 Ts = 1 / (15000x2048)= Configuration CP length Guard interval FS type1 FS type2 Normal CP ?f=15kHz 160 (0) 512 (8 slot0) 224 otherwise 0 (slot) 288 otherwise 144 (1..6) Extended CP ?f=15kHz 512 (0 .. 5) 768 (7 slot0) 512 otherwise 0 (slot) 288 otherwise ?f= 1024 (0..2) 1280 (3 slot0) 1024 otherwise Ts = 1 / (15000x2048)= Ts: Time clock unit for definitions Frame Structure type 2 (TDD) DwPTS, T(variable) One radio frame, Tf = 307200 x Ts = 10 ms One halfframe, 153600 x Ts = 5 ms 0 2 3 4 5 One subframe, 30720 x Ts = 1 ms Guard period, T(variable) UpPTS, Ｔ(variable) One slot, Tslot =15360 x Ts = ms 7 8 9 For 5ms switchpoint periodicity For 10ms switchpoint periodicity LTE Layer 2/3 User Plane LTE protocol stacks PDCP UE RLC MAC Physical Layer PDCP eNode B RLC MAC Physical Layer LTE Layer 2 ? Layer 2 protocols (=MAC amp。 RLC) terminate in BTS (eNode B) ? Also PDCP (Packet Data Convergence Protocol) terminates in eNode B – PDCP includes IP header pression and ciphering Functionality of L2 Layer (MAC, RLC, PDCP) MAC ? Data Transfer via Logical Channels. ? Multiplexing Logical Channels and mapping to Transport Channels. ? Scheduling and Radio Resource Allocation between UEs and between Logical Channels. ? Transport Format Selection. ? Hybrid ARQ Protocol. Functionality of L2 Layer (MAC, RLC, PDCP) RLC ? TM, UM, AM Data Transfer. ? Automatic Repeat Request (ARQ) Protocol. ? Concatenation, Segmentation, Resegmentation. ? InSequence Delivery. Duplicate Detection. Functionality of L2 Layer (MAC, RLC, PDCP) PDCP ? Data Transfer for User and Control Plane. ? Header Compression. ? Ciphering. ? Integrity Protection. ? Sequence Numbering. InSequence Delivery during HO. Duplicate Detection. LTE Layer 3 (RRC) Control Plane LTE protocol stacks RRC UE RLC MAC Physical Layer RRC eNode B RLC MAC Physical Layer ? Radio Resource Control (RRC) signaling is also terminated in eNode B (pared to RNC in WCDMA) ? One of the enablers for the flat model is the lack of macrodiversity ? RRC handles Broadcast, Paging, RRC connection management, Mobility managements and UE measurements LTE Peak Bit Rates Res ou r c e b l oc k s 6 15 25 50 1
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