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Introduction Toto 4G4G LTELTE--Advancedadvanced Overview IntroductionIntroduction toto 4G4G LTELTE--AdvancedAdvanced Overview 1. LTE-Advanced: Requirements and New Technologies Raj Jain 2. Carrier Aggregation Washington University in Saint Louis 3. Coordinated Multipoint Operation Saint Louis, MO 63130 4. Small Cells [email protected] 5. Inter-Cell Interference Coordination Audio/Video recordings of this class lecture are available at: Note: This is the 2nd lecture in a series of lectures on http://www.cse.wustl.edu/~jain/cse574-16/ Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain WashingtonLTE University and in St. LouisLTE-Advancedhttp://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-1 17-2 What is 4G? LTE-Advanced Requirements International Mobile Telecommunication (IMT) Advanced UMTS Rel. 10, 2011H1 Requirements in ITU M.2134-2008 Goal: To meet and exceed IMT-advanced requirements IP based packet switch network Data Rate: 3 Gbps downlink, 1.500 Mbps uplink (low 1.0 Gbps peak rate for fixed services with 100 MHz mobility) using 100 MHz 100 Mbps for mobile services. High mobility to 500 km/hr Spectral Efficiency: 30 bps/Hz using 8x8 MIMO downlink, 15 Feature Cell Cell Edge Peak bps/Hz assuming 4x4 MIMO uplink DL Spectral Efficiency (bps/Hz) 2.2 0.06 15 Cell Spectral Efficiency: DL 3.7 bps/Hz/cell assuming 4x4 UL Spectral Efficiency (bps/Hz) 1.4 0.03 6.75 MIMO, 2.4 bps/Hz/cell assuming 2x2 MIMO (IMT-Adv Seamless connectivity and global roaming with smooth requires 2.6 bps/Hz/cell) handovers Downlink Cell-Edge Spectral Efficiency: 0.12 bps/Hz/User High-Quality Multimedia assuming 4x4 MIMO, 0.07 bps/Hz/user assuming 2x2 MIMO ITU has approved two technologies as 4G (Oct 2010) (IMT-Adv requires 0.075 bps/Hz/user) ¾ LTE-Advanced Ref: 3GPP, “Requirements for Further Advancements for E-UTRA (LTE-Advanced),,” 3GPP TR 36.913 v8.0.1 (03/2009), ¾ WiMAX Release 2 (IEEE 802.16m-2011) http://www.3gpp.org/ftp/specs/archive/36_series/36.913/ Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-3 17-4 LTE-Advanced Requirements (Cont) LTE Advanced Techniques Latency: Less than 10 ms from dormant to active; Three Key Factors: Spectrum (Band, Bandwidth), Spectral Less than 50 ms from camped to active Efficiency, and Cell sizes Mobility: up to 500 kmph Bandwidth: 100 MHz using carrier aggregation Spectrum Flexibility: FDD and TDD, Wider channels up to 5 carriers allowed now. 32 in future. 100 MHz Higher UE power Used if high throughput needed Spectral Efficiency: ¾ Frequency Reuse Factor of 1 ¾ Higher order MIMO (8x8 DL, 4x4 UL) ¾ New MIMO Techniques: Single-user uplink MIMO ¾ Inter-Cell Interference Co-ordination and cancellation Cell Sizes: ¾ Relays ¾ Home eNB Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-5 17-6 Carrier Aggregation Carrier Aggregation (Cont) Aggregation = Combine multiple bands (Component Carriers) Components can be contiguous (adjacent) or non-contiguous (inter-band or intra-band) Each component carrier has a serving cell. Size of different component carrier cells may differ PHY, MAC, RLC are all extended to handle varying number of Fr equenc components y e.g., Larger buffers in RLC to accommodate larger data rate Fre quency Backward compatible with LTE (Single carrier) Each band can be 1.4, 3, 5, 10, or 20 MHz f Maximum 5 component carriers 100 MHz max Each component can be different width Number of components in DL and UL can be different, but Number of components in DL > Number of components in UL Ref: http://www.3gpp.org/technologies/keywords-acronyms/97-lte-advanced Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-7 17-8 MIMO Precoding 8x8 MIMO in DL and 4x4 in UL Used to map the modulation symbols to different antennas MIMO used only when SINR is high Good Channel Depends upon the number of antennas and number of layers If SINR is low, other spectral efficiency techniques, such as, Reference (Pilot) signals are transmitted with the data transmit diversity, are used. Code-Book based precoding: Cell Reference Signals (CRS) Many different transmission modes defined. Non-Code book based precoding: Demodulation Reference UE is informed about the mode to use via signaling Signals (DM-RS) are added before precoding. Modes differ in number of antennas, antenna port, precoding Receiver can infer precoding from the pilots. type, type of reference signal CRS1 DM-RS1 Three new categories of UE: Category 6, 7, 8 Data Data Category 8 supports maximum features Data Data Precoding Precoding Receiver Receiver Transmitter Transmitter Cell-Specific CRS2 DM-RS2 UE-Specific Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-9 17-10 Coordinated Multipoint Operation (CoMP) Relay Nodes To improve performance at cell edge Relay Nodes: Low-power base stations Base stations coordinate transmissions and reception Used to enhance performance at cell edges, hot-spot areas, indoor coverage Joint Transmission: Multiple transmitters in the same subframe Donor eNB (DeNB): Primary base station Dynamic Point Selection: Transmission scheduled from one BS A modified version of E-UTRAN air interface Uu is defined: Joint Reception: Multiple BS receive the signal from one UE and combine Un Both Donor and Relays may use the same/different frequencies UE is informed about different UL/DL decisions Self-Interference: Relay transmission may interfere with its reception on the same frequency Avoided using time sharing Donor does the mobility management eNB eNB eNB eNB Uu Un (a) Joint Transmission (b) Dynamic Point Selection RN DeNB Donor Cell Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-11 17-12 HetNet/Small Cells HetNet/Small Cells (Cont) Macro eNB: Normal Base Station UE selects the BS with the strongest Signal in DL (SSDL) Relay Node (RN): Micro or Pico Cell. Both BS have same SSDL at the edge HeNB: Home eNB for indoor coverage in homes, offices, Cell Range Extension (CRE): Allow small cell to serve more malls. Privately owned and operated. Femto Cell. users by requiring UE to join small cell even if the power is Remote Radio Heads (RRH): Relay nodes connected to DeNB via fiber slightly below the macro cell Interference from macro is mitigated by coordination Femto Cell HeNB eNB Macro Cell SSDLSmall = SSDLMacro SSDLSmall + Offset = SSDLMacro Small Small Cell RN DeNB Cell RN DeNB Donor Cell Macro Cell Ref: 3GPP, “HetNet/Small Cells,” http://www.3gpp.org/hetnet Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-13 17-14 Types of Cells FemtoCells: Key Features Cell (MacroCell): Cover a few miles. Public Access. Open 50-100 m cell radius Area. Indoor -6 MicroCell (10 ): Less than a mile wide. Public Access. Malls, Residential, Small office/home office (SOHO) Hotels, Train Stations Backhaul over DSL PicoCell (10-12): in-Building with public access Plug and Play: Self-Organizing, Self optimizing FemtoCell (10-15): In-Building with restricted access Omni-directional antenna. No sectorization AttoCell (10-18): In-room 10-50 users, 10-40 Mbps, Low cost ZeptoCell (10-21): On-Desk Defined User group No milli, nano cells. Continuation of Macro network: Handover of calls Regular mobile equipment work in femtocells Multiple FemtoCells should coexist Femto Femto Femto New Applications: HD video streaming, LAN services Internet DSL Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-15 17-16 Self-Organizing Network (SON) Management and Configuration Installation Measurement Self-configuration Measurement Self-Configuration Remote configuration by service provider Self-Healing Self-optimization Femtocell senses the channel to detect neighboring cells User installable. 70M UMTS femtocells expected in 2012 May broadcast messages for neighbors Not-physically accessible to the carrier Operator provides femtocell ID. Customer registers location Self-Configures: ¾ Transmission Frequencies ¾ Transmission Power ¾ Preamble: Identifies the segment (IDcell). Some IDs for reserved for femtocells. Helps differentiate from macrocell. ¾ Neighbor Cell list: Helps in handover Turned on/off by the consumer Dynamic topology Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse574-16/ ©2016 Raj Jain 17-17 17-18 Enhanced Inter-Cell Interference Carrier Aggregation with Coordination (eICIC) Cross-Carrier Scheduling ICIC: A eNB sends a “load information” message to the Physical DL Control channel (PDCCH) in macro cell and neighbor eNB about interference level per physical resource small cell is sent on different carriers and may be at a higher power than traffic channels block. The neighbor adjusts DL power levels at those blocks A UE can talk to both BS’s using control channels on different Almost Blank Subframes (ABS): Only control channels and carriers Subframe Subframe cell-specific pilots, no user data Allows UEs in CRE region 1 ms 1 ms to mitigate macro-cell interference = eICIC Power UEs at Cell Edge Power f f Load Info Primary Secondary Secondary Primary ABS Interference on PRB 1,2,3 ABS Carrier Carrier Carrier Carrier I will schedule cell edge UEs on 4&5 ABS Pattern Info Frequency Small eNB eNB Cell eNB eNB eNB eNB Macro Cell Washington University in St.
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