lte概述(存儲版)
【正文】 period (switching from DL UL) Physical Layer definitions – Frame Structure (DL) – Slot/Frame NsymbDL OFDM symbols (=7 OFDM symbols Normal CP) Cyclic Prefix 160 2048 144 2048 144 2048 144 2048 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。 Freq. (Frequency Selective Scheduling) TX RX Tx Rx MIMO Channel DL: OFDMA UL: SCFDMA scalable HARQ: Hybrid Automatic Repeat Request 64QAM Modulation 1 2 2 1 NACK ACK Rx Buffer Combined decoding LTE Architecture Our Key Architectural Concept Flat and Cost effective Mobile Network GSM/EDGE/ UMTS/HSPA Access Core Control WCDMA BTS RNC IMS HLR/HSS LTE / SAE Shift of functionality 2G BTS BSC MSC MGW SGSN GGSN LTE BTS (eNodeB) MME SAEGW MGW ? From CS to PS domain (VoIP), split of functions between eNodeB 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, Segmenta
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