LTE Introduction 0056532 Tzu-chin Liu 15th March 2012

Outline Overview Network architecture Protocol stack Resource element Frame structure TDD frame configuration TDD special subframe MIMO Random access procedure

LTE Overview LTE – Long Term Evolution: The 4th generation telecommunication standards. Evolved from the 3GPP system.(R8) RAN: LTE Core: SAE(System Architecture Evolution) Characteristics: Packet switching All – IP network Higher data rate OFDMA based MIMO supported Lte 是什麼? 是現今4G通訊標準之一 由3gpp演進而來 最大的特色: all ip , pkt switching, high data rate, broadband? --- 使用OFDMA, MIMO等技術; duplex有TDD/FDD

SAE – System Architecture Evolution 接下來看LTE的network Arch. 一般所說的LTE其實包含了兩套標準: LTE/SAE 其中LTE是定義radio access network, SAE 是定義core network. RAN就是指e-utran這邊 從UE(手機)連上基地台enodeB, 接著才練上核心網 他的core裡有幾個重要的entity: 第一個是mme: …

Protocol Stack User plane: Control plane:

Resource element The basic unit when allocating carrier resource. Resource Element(RE): One subcarrier by one symbol Resource Block(RB): 12 subcarriers by 7 symbol Resource Element Group(REG): For control plane One REG has 4 or 6 REs.

LTE Frame Structure One radio frame has 10 ms: Duplexing: 10 subframes, each of 1 ms. Duplexing: FDD TDD 在傳輸時把時間單位切成一個個的frame 一個frame是10millisec.

LTE TDD Frame UL-DL configuration: Special Subframe: LTE TDD can have 7 UL-DL subframe configurations. Special Subframe: Provide a gap to allow switching from DL to UL a transition subframe. 接下來要講怎麼樣去透過frame的設定來做雙工

LTE TDD UL-DL configuration

MIMO Multiple-Input Multiple-Output: Better throughput multiple antennas at both the transmitter and receiver to improve communication performance. Better throughput Longer transmission distance

MIMO modes Downlink Transmission Mode: Release 8 have defined 7 transmission modes.

Random Access Procedure Random access purpose: Set up the RRC (Radio Resource Control) connection when: Idle state or initial power on Handover Synchronization Reset RRC

Random Access Procedure

Q & A

References TDD LTE Air Interfaces v.1 TS 33.401 3GPP System Architecture Evolution (SAE): Security architecture TS 36.213 Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures TS 36.321 Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification