LTE-A : 4G Wireless Broadband Networks 中山大學 電機系 許蒼嶺教授

行動通信標準演進

Evolution of Wireless Access Technologies 4G Air Interfaces CDMA 2000-1X HRPDA 1x EVDO 1x EVDV Rel. C Rel. D Wide Area Mobile 3GPP2 MOBILE BROADBAND GSM GPRS EDGE UMTS HSPA LTE 3GPP 802.16e (Mobile WIMAX) Mobile Industry Coverage/Mobility Metro Area Nomadic 802.16a/d (Fixed NLOS) Fixed Wireless Industry 802.11n (smart antennas) 802.11 Mesh extns. 802.16 (Fixed LOS) Dial Up DSL Experience Local Area Fixed Data Rates (kbps) 802.11b/a/g 100,000 + Higher Data Rate / Lower Cost per Bit

3GPP

3GPP Radio Access Milestones

Operator’s Service Stack IMS Layer Application services Mobility, Policy and Administration Services EPC Core network Access technologies connection gateways Access Technologies WiMAX LTE DSLAM WiFi Devices

Population penetration of mobile, fixed and broadband across Asia-Pacific

TDMA/OFDM/OFDMA

Modulations & Channel Size Uplink Mandarory US European Downlink Mandarory Access Range: QPSK > QAM-16 > QAM-64 Data Rate: QAM-64 > QAM-16 > QPSK

Frame Durations with TDD Frame Structure 0.5/1/2 ms

Number of PS in 16-QAM Frame duration = 1 ms Signal (Baud) rate = 16 Mbauds/sec 4 bits in a signal (baud) using 16-QAM Ts=LT, Data rate, R = LS = 4 x16 = 64 Mbps Number of PS (Physical Slot) (64 Mbps x 1 ms) / 16 bits = 4000 Assume every PS = 16 bits

4G: LTE-A vs IEEE 802.16m ITU-R’s IMT-Advanced (4G) requirements up to 1 Gbps in static or low mobility environment up to 100 Mbps in high-speed mobile environment Multicarrier is the technology to utilize wider bandwidth for parallel data transmission across multiple RF carriers. IEEE 802.16m LTE-A Carrier Aggregation (CA) Component Carrier (CC)

IEEE 802.16m OFDMA Parameters Nominal Channel Bandwidth (MHz) 5 7 8.75 10 20 Over-sampling Factor 28/25 8/7 Sampling Frequency (MHz) 5.6 8 11.2 22.4 FFT Size 512 1024 2048 Sub-Carrier Spacing (kHz) 10.937500 7.812500 9.765625 Useful Symbol Time Tu (μs) 91.429 128 102.4 Cyclic Prefix (CP) Tg=1/8 Tu Symbol Time Ts (μs) 102.857 144 115.2 FDD No. of OFDM symbols per Frame 48 34 43 Idle time (μs) 62.857 104 46.40 TDD 47 33 42 TTG + RTG (μs) 165.714 248 161.6 Tg=1/16 Tu Symbol Time Ts(μs) 97.143 136 108.8 51 36 45 45.71 50 35 44 142.853 240 212.8 Number of used subcarriers 433 865 1729

802.16m Guard Bands

Baud Rate B: baud rate, number of symbols in one second S: number of symbols in an OFDMA frame T: OFDMA frame duration N: number of carriers in an OFDMA frame B = ( ) x N

Data Rate vs Baud Rate R: data rate (bps) M: number of different signal elements in MCS B: baud rate, number of symbols in one second R = B x

LTE Frame Structure Assume total BW = 30 Mhz and 64-QAM One sub-carrier = 15 Khz Total sub-carriers = 30 MHz/15 Khz = 2000 sub-carriers Total capacity (Data rate) = 2000 x 14000 symbols/sec x 6 bits/symbol = 168 Mbps One OFDMA frame (10 msec) = 10 sub-frames One sub-frame (1 msec) = 2 slots One slot (0.5 msec) = 7 symbols Symbol rate = 7/0.5 msec = 14000 symbols/sec One RE = One symbol x one sub-carrier One RB = 7 symbols x N sub-carriers

 

Frame time = 5 msec , Number of carriers = 192   Frame time = 5 msec , Number of carriers = 192 Data Rate = (360/5 msec)x192= 13.824 Mbps

LTE-A Enhanced Multicast Broadcast Service (EMBS)

Channel Coding Systematic bits Turbo coding 1/3 Systematic bits Parity bits Mapping to the circular buffer Systematic bits Parity bits

不同重傳次數的HARQ封包 RV=0 RV=1 RV=2 RV=3 Coding rate=3/4 1st transmission Systematic bits Parity bits 1st transmission 2nd transmission 3rd transmission 4th transmission Coding rate=3/4

HARQ在Uplink的運作流程 + 1st transmission 2nd transmission 3rd transmission ERROR MN NACK BS ACK success ERROR 1st transmission 2nd transmission || 3rd transmission + 4th transmission MN’s HARQ buffer BS’s HARQ buffer

LTE-A: E-MBS Deployment with Broadcast Only and Mixed Carrier

LTE-A: Carrier Types From the perspective of an advanced MS (AMS) Primary carriers exchanges traffic and control signals with an advanced BS (ABS) mobility, state, and context Secondary carriers An ABS can additionally assign secondary carrier(s) to an AMS Controlled by the ABS through the primary carrier

LTE-A: Carrier Types From the perspective of an ABS Fully configured carrier carrying all control channels synchronization, broadcast, multicast, and unicast control channels both single-carrier and multicarrier AMSs can be served Partially configured carrier primarily to support downlink only transmission only for frequency-division duplex (FDD) deployment a dedicated EMBS carrier is one example

Multicarrier Frame Structure (LTE-A and WiMAX 802.16m) An example of multicarrier frame structure with legacy support.

Multicarrier Transceiver Architectures (LTE-A) Basic concept of subcarrier alignment.

Multicarrier Transceiver Architectures (LTE-A) Different types of AMS transceiver architecture for multicarrier aggregation.

Network entry procedure for multicarrier support. Network Entry (LTE-A) Network entry procedure for multicarrier support. AAI: Advanced Air Interface AAI_REG-REQ: 3 bits

Activation and Deactivation of Assigned Carriers (LTE-A) Multilevel carrier management scheme.

Handover (LTE-A)

Relay Related Connections

Fractional Frequency Reuse (FFR) for Directional Antenna

CA Scenarios and Component Carrier (CC) Types (LTE-A) Example of carrier aggregation scenarios: a) contiguous aggregation of five component carriers with equal bandwidth b) non-contiguous aggregation of component carriers with different bandwidths

Primary and Secondary CCs (LTE-A) UE served bPCell/SCell configuration for different y the same eNB