LTE Downlink Uplink FDD Frequency Division Duplex FDD

LTE Downlink & Uplink

FDD (Frequency Division Duplex) • FDD為分頻雙 • FDD利用不同頻率來分隔上傳與下 載的訊號，因此e. NB傳送及接收的 資料互不影響 Frequency • FDD的訊框架構 https: //www. 2 cm. com. tw/2 cm/zhtw/tech/9 AC 15 B 5620004618 B 2 A 90 D 7 E 2 D 281291 Time

TDD (Time Division Duplex) • TDD為分時雙 • TDD利用不同時間來分隔上傳與下 載的訊號 Frequency • TDD的訊框設計，可依實際上下行 需求做配置，較有彈性 https: //www. 2 cm. com. tw/2 cm/zhtw/tech/9 AC 15 B 5620004618 B 2 A 90 D 7 E 2 D 281291 Time

TDD的訊框架構 • Dw. PTS (Downlink Pilot Time Slot)為下行子訊框 • Up. PTS (Uplink Pilot Time Slot)為上行子訊框 • GP (Guard Period)為保護時間，也是上下行切換的 時間點 DL UL UL DL • Dw. PTS、GP、Up. PTS在一個子訊框內所占的時間 比例，可依不同的需求來做調整 https: //www. 2 cm. com. tw/2 cm/zhtw/tech/9 AC 15 B 5620004618 B 2 A 90 D 7 E 2 D 281291

DL & UL - Channels Physical Downlink Control Channel 載送UE的 控制訊息 Physical Uplink Control Channel 載送UE的控制 訊號到基地台 Physical Uplink Shared Channel Physical Downlink Shared Channel 載送UE的資料 訊號到基地台

Downlink - OFDMA Frame Duration = 10 ms (10 Sub-frame) Sub-frame = 1 ms (2 Slots) Slot = 0. 5 ms (7 Symbols) • • Carrier = 180 KHz (12 Sub-carriers) Sub-carrier = 15 KHz • • RE (Resource Element) = 1 Symbol * 1 Sub-carrier RB (Resource Block) = 1 Slot * 1 Carrier OFDMA Frame … • • • f Bandwidth = 180 MHz Modulation type = 64 -QAM (1 Symbol = 6 bits) RB 1個RE的Data Rate 1個RB的Data Rate Sub-carrier … RE t Symbol Slot = 0. 5 ms Sub-frame = 1 ms OFDMA Frame Duration = 10 ms

FTP、ICMP & HTTP byte MAC Header RLC Header 2 2 PDCP Header 2 共 56 + X bytes Modulation type = 64 -QAM (1 Symbol = 6 bits) 1個RB的Data Rate 1 RB可傳的資料量 假設 1 RB傳 1個封包 X = 63 – 56 = 7 bytes TCP Header IP Header Application Header Payload Padding CRC 20 20 3 X 5 2

Bit Rate(Mbps) MDR t (sec) Overflow ：λ > μ Underflow ：λ < μ Licensed band Mean data rate = MDR Queue Length μ λ Arrival rate Threshold Departure rate Unlicensed band

Layers Data Flow lte-enb-rrc. cc lte-pdcp. cc lte-rlc. cc lte-enb-mac. cc lte-enb-phy. cc 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

RRC (Radio Resource Control) Layer RRC層是對無線資源進行分配並發送相關訊息 lte-enb-rrc. cc Fig. LTE radio protocol stack architecture for the e. NB on the data plane 參考資料: https: //www. nsnam. org/docs/models/html/lte-design. html

PDCP (Packet Data Convergence Control) Layer (1/3) PDCP層是處理Header的壓縮及加密 lte-pdcp. cc Fig. LTE radio protocol stack architecture for the e. NB on the data plane 參考資料: https: //www. nsnam. org/docs/models/html/lte-design. html

PDCP (Packet Data Convergence Control) Layer (2/3) lte-pdcp. cc 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

PDCP (Packet Data Convergence Control) Layer (3/3) lte-pdcp. cc 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

RLC (Radio Link Control) Layer (1/2) RLC層包含了 ARQ 及 HARQ 等重傳機制，以及為了配合 下層 MAC 的各個 frame 大小進行封包的分割與重組 lte-rlc. cc Fig. LTE radio protocol stack architecture for the e. NB on the data plane 參考資料: https: //www. nsnam. org/docs/models/html/lte-design. html

RLC (Radio Link Control) Layer (2/2) lte-rlc. cc 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

MAC Layer (1/2) MAC層則主要做 Qo. S (Quality of Service) 的排程 lte-enb-mac. cc Fig. LTE radio protocol stack architecture for the e. NB on the data plane 參考資料: https: //www. nsnam. org/docs/models/html/lte-design. html

MAC Layer (2/2) lte-enb-mac. cc 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

建立DL PHY PDU 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

PHY Layer (1/2) PHY層將資料轉為實體訊號發送 lte-enb-phy. cc Fig. LTE radio protocol stack architecture for the e. NB on the data plane 參考資料: https: //www. nsnam. org/docs/models/html/lte-design. html

PHY Layer (2/2) lte-enb-phy. cc 參考來源: https: //www. tutorialspoint. com/lte_layers_data_flow. htm

LAA traced code (NS-3)

Block diagram of coexistence simulator https: //www. nsnam. org/~tomh/ns-3 -lbt-presentations/LAA-Wi-Fi-Coexistence-May 2016. pdf

LBT Algorithm

NS 3 traced code (1/11) LBT Channel Access Manager lbt-access-manager-ed-threshold-test. cc 檔

NS 3 traced code (2/11) RNTI (Radio Network Temporary Identifier) e. NB用來辨識UE身分的ID

NS 3 traced code (3/11) LBT Channel Access Manager lbt-access-manager-ed-threshold-test. cc 檔

NS 3 traced code (4/11) lbt-access-manager. cc 檔 • 監聽 Wi-Fi PHY 的事件， 再回報Lbt. Access. Manager • 監聽內容如下: • • • Rx Tx CCA Busy Sleep Wakeup

NS 3 traced code (5/11) lbt-access-manager. cc 檔 • 監聽NAV的事件，再回報 Lbt. Access. Manager • 監聽內容如下: • NAV開始與重置 • ACK Timeout開始與重置 • CTS Timeout開始與重置

Slot time 設為 9 us CCA時間設為 43 us contention window最小值設為 15 contention window最大值設為 63 Tx. OP的channel access grant時間設為 8 ms 使用Reservation Signal 當資料還沒有準備好傳 輸時使用預留訊號 根據他的定義來更新CW的大小 更改CW記錄

NS 3 traced code (7/11)

NS 3 traced code (8/11)

NS 3 traced code (10/11)

NS 3 traced code (11/11) Channel state 是 busy的情形，取消等待 Backoff Event Channel state 非 busy的情形 Backoff Count=Backoff Count - 1