LTE and the Evolution to LTE-Advanced Fundamentals

Transcription

1 LTE and the Evolution to LTE-Advanced Fundamentals Based on the 2 nd Edition book LTE and the Evolution to 4G Wireless Design and Measurement Challenges Presented by: Agilent Technologies

2 Agenda Introduction to LTE - Evolution and Motivation - Major features and requirements Air Interface Concepts - Frequency bands - OFDMA/SC-FDMA - Structure frame, slots, resource blocks - Physical signals and channels MIMO Concepts LTE-Advanced Major Features and Design Challenges - Carrier Aggregation - Enhanced Uplink Multiple Access (clustered SC-FDMA) - High Order MIMO - Other Study Items Question and Answer

3 Cellular Evolution Technology evolution Market evolution W-LAN Increasing efficiency, bandwidth and data rates 2G 2.5G 3G 3.5G 3.9G/ 4G 4G / IMT- Advanced PDC (Japan) imode W-CDMA (FDD & TDD) HSDPA HSUPA HSPA+ / E-HSPA HSCSD GSM (Europe) TD-SCDMA (China) EDGE Evolution GPRS LTE (R8/9 FDD & TDD) LTE-Advanced (R10 & beyond) IS-136 (US TDMA) E-GPRS (EDGE) 1x EV-DO 0 A B e (Mobile WiMAX) IS-95A (US CDMA) IS-95B (US CDMA) cdma2000 (1x RTT) m / WiMAX2 WirelessMAN-Advanced d (Fixed WiMAX) WiBRO (Korea) b a/g h n ac ad

4 3GPP UMTS Long Term Evolution Release Stage 3: Core specs complete Main feature of Release Rel-99 March 2000 UMTS 3.84 Mcps (W-CDMA FDD & TDD) Rel-4 March Mcps TDD (aka TD-SCDMA) Rel-5 June 2002 HSDPA Rel-6 March 2005 HSUPA (E-DCH) Rel-7 Dec 2007 HSPA+ (64QAM DL, MIMO, 16QAM UL). LTE & SAE Feasibility Study, Edge Evolution Rel-8 Dec 2008 LTE Work item OFDMA air interface SAE Work item New IP core network UMTS Femtocells, Dual Carrier HSDPA Rel-9 Dec 2009 Multi-standard Radio (MSR), Dual Carrier HSUPA, Dual Band HSDPA, SON, LTE Femtocells (HeNB) LTE-Advanced feasibility study, MBSFN Rel-10 March 2011 LTE-Advanced (4G) work item, CoMP Study Four carrier HSDPA Rel-11 Sept 2012 CoMP, edl MIMO, eca, MIMO OTA, HSUPA TxD & 64QAM MIMO, HSDPA 8C & 4x4 MIMO, MB MSR Rel-12 June -> Sept 2014 New carrier type, LTE-Direct, Active Antenna Systems, small cells Rel-13 Dec 2015 Just starting more CA

5 LTE Commercial Networks FDD & TDD

6 LTE-TDD Investment Worldwide

7 LTE Major Features Feature Access modes Channel BW 1RB = 12 subcarriers = 180 khz Transmission Scheme Modulation Formats MIMO Technology Peak Data Rates Bearer services Transmission Time Interval (TTI) Capability FDD & TDD 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz 6 RB 15 RB 25 RB 50 RB 75 RB 100 RB Downlink: OFDMA (Orthogonal Frequency Division Multiple Access) Uplink: SC-FDMA (Single Carrier Frequency Division Multiple Access QPSK, 16QAM, 64QAM Downlink: Tx diversity, Rx diversity, Single-User MIMO (up to 4x4), beamforming Uplink: Multi-User MIMO Downlink: 300 Mbps (4x4 MIMO, 20 MHz, 64QAM) Uplink: 75 Mbps ( 20 MHz BW, 64QAM) Packet only no circuit switched voice or data services are supported voice must use VoIP 1 ms

8 Agenda Introduction to LTE - Evolution and Motivation - Major features and requirements Air Interface Concepts - Frequency bands - OFDMA/SC-FDMA - Structure frame, slots, resource blocks - Physical signals and channels MIMO Concepts LTE-Advanced Major Features and Design Challenges - Carrier Aggregation - Enhanced Uplink Multiple Access (clustered SC-FDMA) - High Order MIMO - Other Study Items Question and Answer

9 Frequency Bands Release Independent Release independent means that a band defined in a later release can be applied to an earlier release This significantly simplifies the specifications There are currently 42 frequency bands defined by 3GPP for LTE with more on the way in Release 12 FDD TDD Release (excl. 15,16*) Release Release Release Release 12 30, 31, plus * Bands 15 and 16 are specified by ETSI only for use in Europe

10 LTE FDD Frequency Bands March 2014 Band Uplink MHz Downlink MHz Width Duplex Gap * * N/A Width Uplink Band Duplex spacing Gap Frequency Width Downlink Band There is a lot of overlap between band definitions for regional reasons The Duplex spacing varies from 30 MHz to 799 MHz The gap between downlink and uplink varies from 5 MHz to 680 MHz Narrow duplex spacing and gaps make it hard to design filters to prevent the transmitter spectral regrowth leaking into the receiver (self-blocking) Bands 13, 14, 20 and 24 have reversed uplink downlink frequencies Bands 15 and 16 are specified by ETSI only for use in Europe Band 29 restricted to E-UTRA operation when carrier aggregation is configured.

11 LTE TDD Frequency Bands March 2014 Band Uplink MHz Downlink MHz Width Width Transceive Band Frequency

12 Orthogonal Frequency Division Multiplexing Figure 1: Frequency-Time Representation of an OFDM Signal LTE provides QPSK, 16QAM, 64QAM as downlink modulation schemes Each sub-carrier carries a separate low-rate stream of data 15 khz subcarrier spacing Each sub-carrier is independently modulated Cyclic prefix is used as guard interval to minimize inter-symbol interference

13 OFDMA: The Basis for LTE s Downlink Transmission OFDM is already widely used in non-cellular technologies and was considered by ETSI for UMTS in 1998 CDMA was favored since OFDM requires large amounts of baseband processing which was not commercially viable at that time OFDMA advantages Almost completely resistant to multi-path due to very long symbols Optimum use of available spectrum and efficient receiver architecture Ideally suited to MIMO due to easy matching of transmit signals to the uncorrelated RF channels OFDMA disadvantages Sensitive to frequency errors and phase noise due to close subcarrier spacing Sensitive to Doppler shift which creates interference between subcarriers Pure OFDM creates high PAR which is why SC-FDMA is used on UL More complex than CDMA for handling inter-cell interference at cell edge

14 Why SC-FDMA for the Uplink? SC-FDMA is a new hybrid transmission scheme combining the low PAR single carrier methods with the frequency allocation flexibility and long symbol time of OFDMA DFT is first applied to block of N TX modulated symbols to transform them into frequency domain Sub-carrier mapping allows flexible allocation of signal to available sub-carriers SC-FDMA is sometimes referred to as Discrete Fourier Transform Spread OFDM = DFT- SOFDM Time domain Frequency domain Time domain Coded symbol rate= R DFT Sub-carrier Mapping IFFT CP insertion N TX symbols Size-N TX Size-N FFT TR Figure Transmitter structure for SC-FDMA.

15 Comparing OFDMA and SC-FDMA QPSK example using M=4 subcarriers 1, 1-1,-1-1, 1 1, -1 1,1 1, -1-1,1-1,-1-1,1 Q 1,1 Time I -1,-1 1,-1 V V CP CP f c 15 khz Frequency f c 60 khz Frequency OFDMA Data symbols occupy 15 khz for one OFDMA symbol period SC-FDMA Data symbols occupy M*15 khz for 1/M SC-FDMA symbol periods

16 OFDMA Signal Generation QPSK example using M=4 subcarriers One OFDMA symbol period Each of M subcarriers is encoded with one QPSK symbol M subcarriers can transmit M QPSK symbols in parallel -1,1-1,-1 Q 1,1 I 1,-1 1, , , f 0 (F cycles) f khz (F+1 cycles) f khz (F+2 cycles) The amplitude of the combined four subcarrier signal varies widely depending on the symbol data being transmitted 1, f khz (F+3 cycles) Peak created by transmitting four identical symbols Null created by transmitting four different symbols One symbol period With many subcarriers the waveform becomes Gaussian not sinusoidal

17 SC-FDMA Signal Generation QPSK example using M=4 subcarriers To transmit the sequence: 1, 1-1,-1-1, 1 1,-1 using SC-FDMA first create a time domain representation of the IQ baseband sequence -1,1-1,-1 Q 1,1 I 1, V(I) +1-1 V(Q) One SC-FDMA symbol period One SC-FDMA symbol period Perform a DFT of length M and sample rate M/(symbol period) to create M FFT bins spaced by 15 khz V,Φ Frequency Shift the M subcarriers to the desired allocation within the system bandwidth V,Φ Frequency Perform an IFFT to create a time domain signal of the frequency shifted original Insert the cyclic prefix between SC-FDMA symbols and transmit Important Note: The PAR is the same as the original QPSK data symbols

18 Complimentary Cumulative Distribution Function Gaussian 16 QAM SC-FDMA CCDF is several db below Gaussian reference line - what OFDMA would have given.

19 Physical Layer Definitions - Frame Structure Frame Structure type 1 (FDD) One slot = 0.5 ms FDD: Uplink and downlink are transmitted separately #0 #1 #2 #3. #18 #19 One subframe = 1ms One radio frame = 10 ms Transmission time interval is 1 subframe = 2 slots Subframe 0 Subframe 1 Subframe 9 Frame Structure type 2 (TDD) One half-frame = 5 ms 5ms switch-point periodicity: Subframe 0, 5 and DwPTS for downlink, Subframe 2, 5 and UpPTS for Uplink 10ms switch-point periodicity: Subframe 0, 5,7-9 and DwPTS for downlink, Subframe 2 and UpPTS for Uplink One radio frame = 10 ms One subframe = 1 ms For 5ms switch-point periodicity #0 #2 #3 #4 #5 #7 #8 #9 DwPTS, T(variable) UpPTS, T(variable) Guard period, T(variable) One slot = 0.5 ms For 10ms switch-point periodicity

20 TDD Downlink and Uplink Allocation 5ms switch-point periodicity Subframe 0, 5 and DwPTS for downlink, Subframe 2, 7 and UpPTS for uplink #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 DwPTS GP UpPTS DwPTS GP UpPTS 10ms switch-point periodicity Subframe 0, 5-9 and DwPTS for downlink,subframe 2 and UpPTS for Uplink #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 DwPTS GP UpPTS : downlink; :uplink DwPTS: Downlink Pilot Timeslot GP: Guard Period UpPTS: Uplink Pilot Timeslot

21 TDD Downlink and Uplink Switch-Points Depends on configuration #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 DwPTS GP UpPTS DwPTS GP UpPTS Configuration Switchpoint periodicity Subframe number ms D S U U U D S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D D: downlink; U: uplink S: Special subframe

22 Special Subframe Configuration DwPTS GP UpPTS Subframe 1 Special subframe New in 3GPP Rel 11 Special subframe config Normal Cyclic prefix length in OFDM symbols Extended Cyclic prefix length in OFDM symbols DwPTS GP UpPTS DwPTS GP UpPTS Golden Rule: the total length for DwPTS + GP + UpPTS = 1ms = 14 symbols in normal CP or 12 symbols in extended CP DwPTS: Downlink Pilot Signal carries PDCCH, P-SS, RS, PDSCH GP: Guard Period, separates between the UL and DL UpPTS: Uplink Pilot Signal carries PRACH, S-RS

23 Special Subframe Configuration DwPTS GP UpPTS Subframe 1 Special subframe Special subframe config Normal Cyclic prefix in DL and UL DwPTS GP UpPTS Max cell size km km km km km km km km km Golden Rule: the total length for DwPTS + GP+ UpPTS = 1ms = 14 symbols in normal CP or 12 symbols in extended CP DwPTS: Downlink Pilot Signal carries PDCCH, P-SS, RS, PDSCH GP: Guard Period, separates between the UL and DL UpPTS: Uplink Pilot Signal carries PRACH, S-RS

24 Slot Structure and Resource Block (RB) One downlink slot, T slot A Resource Element (RE) is the smallest unit in the physical layer and occupies one symbol in the time domain and one sub-carrier in the frequency domain. subcarriers DL N symb OFDM symbols : Resource Block (RB) RB x N sc DL N symb Resource Element (RE) (k, l) A Resource Block (RB) is basic scheduling unit. It contains: 7 symbols (1 slot) X 12 subcarriers for normal cyclic prefix or; 6 symbols (1 slot) X 12 subcarriers for extended cyclic prefix Minimum user allocation is 1 ms (2 slots) and 180 khz (12 subcarriers, 1RB). subcarriers Condition - Uplink N RB sc N UL symb Normal cyclic prefix 12 7 Extended cyclic prefix 12 6 : l=0 l= N DL symb 1 DL RB Condition - Downlink N symb N sc Normal f=15khz 12 7 cyclic prefix Extended f=15khz 12 6 cyclic prefix f=7.5khz 24 3

25 Transmission Bandwidth Configuration Channel bandwidth BW Channel [MHz] Transmission bandwidth configuration N RB Transmission bandwidth configuration N Sub-carriers

26 LTE Physical Layer Overview LTE air interface consists of two main components: signals and channels - Physical Signals These are generated in Layer 1 and are used for system synchronization, cell identification and radio channel estimation - Physical Channels These carry data from higher layers including control, scheduling and user payload

27 DL Mapping of Logical,Transport & PHY Channels/Signals Logical Channels BCCH PCCH CCCH DCCH DTCH MCCH MTCH Transport Channels BCH PCH DL-SCH MCH DCI CFI HI Physical Channels PBCH PDSCH PMCH PDCCH PCFICH PHICH P-SS S-SS C-RS Logical Transport Physical BCCH Broadcast Control Channel BCH Broadcast Channel PBCH Physical Broadcast Channel PCCH Paging Control Channel PCH Paging Channel PDSCH Physical Downlink Shared Channel CCCH Common Control Channel BCH Broadcast Channel PMCH Physical Multicast Channel DCCH Dedicated Control Channel DL-SCH Downlink Shared Channel PDCCH Physical Downlink Control Channel DTCH Dedicated Traffic Channel MCH Multicast Channel PCFICH Physical Control Format Indicator Channel MCCH Multicast Control Channel DCI Downlink Control Information PHICH Physical Hybrid ARQ Indicator Channel MTCH Multicast Traffic Channel CFI Control Format Indicator P-SS Primary synchronization signal HI HARQ Indicator S-SS Secondary synchronization signal C-RS Cell-specific reference signal

28 LTE Air Interface: Downlink Physical Signals P-SS - Primary Synchronization Signal S-SS - Secondary Synchronization Signal C-RS Cell-Specific Reference Signal (Pilot) Base Station (enb) P-SS: Used in cell search and initial synchronization procedures Carries part of the cell ID (one of 3 sequences) and identifies 5 ms timing S-SS: Used to identify cell-identity groups. Also identifies frame timing (10 ms) Carries remainder of cell ID (one of 168 binary sequences) C-RS: Used for DL channel estimation and coherent demodulation User Equipment (UE)

29 LTE Air Interface: Downlink Physical Channels (1 of 2) Broadcast Channel PBCH Physical Broadcast Channel Indicator Channels PCFICH Physical Control Format Indicator Channel PHICH Physical Hybrid-ARQ Indicator Channel Base Station (enb) PBCH: Carries cell specific information such as system bandwidth, number of Tx antennas etc PCFICH: Carries information on the number of OFDM symbols used for transmission of PDCCH s in a sub-frame PHICH: Carries the hybrid-arq ACK/NACK feedback to the UE for the blocks received User Equipment (UE)

30 LTE Air Interface: Downlink Physical Channels (2 of 2) Control Channel PDCCH Physical Downlink Control Channel Shared (Payload) Channel PDSCH - Physical Downlink Shared Channel Base Station (enb) PDCCH Carries uplink and downlink scheduling assignments and other control information depending on format type PDSCH Carries downlink user data User Equipment (UE)

31 Downlink FDD Resource Mapping (Single Antenna Port) N symb DL OFDM symbols (=7 OFDM Normal CP) 1slot = (x Ts) slot Cyclic Prefix 1 slot Ts = 1 / (15000x2048)=32.552nsec Sub-Carrier (RB) Time (Symbol) 1 Subframe = 2 slots S-SS on 2 nd last symbol of slot # 0 & 10 P-SS on last symbol of slot 0 & 10 P-SS S-SS PBCH PDCCH PDSCH Reference Signal 1 frame = 10 SF= 20 slots

32 Downlink TDD Frame Structure N symb DL OFDM symbols (=7 OFDM Normal CP) 1slot = (x Ts) slot Cyclic Prefix 1 slot Ts = 1 / (15000x2048)=32.552nsec Subframe 0 S-SS on last symbol of subframe 0 & 5 Subframe 1 (Special Field) P-SS on 3 rd symbol subframe 1 & 6 Subframe 2 Subframe 3 Downlink P-SS S-SS PBCH PDCCH PDSCH Reference Signal Uplink Reference Signal (Demodulation) PUSCH UpPTS #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 1 frame

33 Downlink FDD Frame Structure Analysis C-RS Cell-Specific Reference Signal (Pilot) P-SS - Primary Synchronization Signal S-SS - Secondary Synchronization Signal PBCH - Physical Broadcast Channel PCFICH Physical Control Format Indicator Channel PHICH Physical Hybrid ARQ Indicator Channel PDCCH - Physical Downlink Control Channel PDSCH - Physical Downlink Shared Channel Slot#0 Symbol#0 RS + PCFICH + PHICH + PDCCH Frequency (Sub-Carrier or RB) Time (Symbol)

34 Technical Differences Between FDD and TDD - Downlink a0,...,, a1 a A 1 Transport block CRC attachment b0,...,, b1 b B 1 Code block segmentation Code block CRC attachment cr0 cr1,..., cr, K r 1 Channel coding ( i) ( i) dr0, dr1,..., dr er0 er1,..., er ( i) Dr 1, E r 1 Rate matching TDD and FDD differences f0,...,, f1 f G 1 Code block concatenation code words Scrambling Scrambling Modulation mapper Modulation mapper Layer mapper layers Precoding Resource element mapper Resource element mapper OFDM signal generation OFDM signal generation antenna ports

35 Uplink Signal Types and Channels Logical Channels CCCH DCCH DTCH Transport Channels RACH UL-SCH Physical Channels PRACH PUSCH PUCCH Control information can be carried in PUSCH and PUCCH UCI (Uplink Control Information) Transport Channel UL-SCH RACH UCI Channel Name Uplink Shared Channel Random Access Channel Uplink Control Information Physical Channel Physical channel Name Purpose PUSCH Physical Uplink Shared Channel User data, Channel reports, RRC setup information PRACH PUCCH PUSCH Physical Random Access Channel Physical Uplink Control Channel Physical Uplink Shared Channel Initiates connection Channel reports, HARQ-ACK, Scheduling Request, SR

36 LTE Air Interface: Uplink Physical Signals DM-RS - (Demodulation) Reference Signal S-RS - (Sounding) Reference Signal Base Station (enb) DM-RS: There are two types of DM-RS. PUCCH-DMRS and PUSCH-DMRS PUSCH-DMRS: Used for uplink channel estimation PUCCH-DMRS: Used for uplink channel estimation. Only transmitted when no PUSCH is transmitted S-RS: Used for uplink channel quality estimation when no PUCCH or PUSCH is scheduled. User Equipment (UE)

37 LTE Air Interface: Uplink Physical Channels Random Access Channel PRACH - Physical Random Access Channel Control Channel PUCCH Physical Uplink Control Channel Shared (Payload) Channel PUSCH - Physical Uplink Shared Channel Base Station (enb) PRACH: Used for call setup Allows the enb to calculate the time delay to the UE and identify it prior to establishing a packet connection PUCCH: Carries ACK/NACK for downlink packets, CQI information and scheduling requests Never transmitted at same time as PUSCH from the same UE PUSCH: Carries uplink user data Carries control information User Equipment (UE)

38 Uplink FDD Frame Structure - PUSCH Mapping DL N symb The Cyclic Prefix is created by prepending each symbol with a copy of the end of the symbol OFDM symbols (= 7 OFDM Normal CP) (x Ts) CP 0 CP 1 CP 2 CP 3 CP 4 CP 5 CP 6 etc. Ts = 1/(15000 x 2048) = 32.6 ns 1 slot = Ts = 0.5 ms 1 sub-frame = 2 slots = 1 ms PUSCH - Physical Uplink shared Channel Reference Signal (Demodulation) #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 1 frame = 10 sub-frames = 10 ms

39 Uplink FDD Frame Structure Analysis PUSCH - Physical Uplink Shared Channel PUSCH-DMRS Demodulation Reference Signal (pilot) Slot #0 Symbol #0: PUSCH Frequency (Sub-Carrier or RB) Time (Symbol)

40 Uplink FDD Frame Structure Analysis PUSCH - Physical Uplink Shared Channel PUSCH-DMRS Demodulation Reference Signal (pilot) Slot #0 Symbol #3: PUSCH-DMRS Frequency (Sub-Carrier or RB) Time (Symbol)

41 Technical Differences Between FDD and TDD - PRACH TDD only! Format 4 is only used in TD-LTE, and only when special subframe configurations with UpPTS lengths of 2 symbols PRACH format4

42 Technical Differences Between FDD and TDD - Sounding RS In FDD, Sounding RS is transmitted on the last SC-FDMA symbol of the sub-frame. In TDD, Sounding RS is also transmitted in UpPTS. Sounding RS is very important in TDD, especially for beamforming Downlink Subframe Special Subframe Uplink Subframe

43 Uplink Mapping PUSCH 64QAM Demodulation Reference Signal (for PUSCH) 16QAM QPSK BPSK(1a) QPSK(1b) PUCCH Demodulation Reference Signal for PUCCH format 1a/1b Zadoff-Chu PUSCH 3RB QPSK PUSCH < 3RB or PUCCH

44 Agenda Introduction to LTE - Evolution and Motivation - Major features and requirements Air Interface Concepts - Frequency bands - OFDMA/SC-FDMA - Structure frame, slots, resource blocks - Physical signals and channels MIMO Concepts LTE-Advanced Major Features and Design Challenges - Carrier Aggregation - Enhanced Uplink Multiple Access (clustered SC-FDMA) - High Order MIMO - Other Study Items Question and Answer

45 Multi-Antenna Techniques Summary SISO - No diversity protection against fading Tx Rx Tx Rx : SIMO - Rx diversity - Rx smart antenna (beamforming) - Improved SINR MISO - Tx diversity Tx : Rx - Tx smart antenna (beamforming) Tx : : Rx - Improved SINR MIMO - Tx/Rx diversity - Tx/Rx smart antenna (beamforming) - Spatial multiplexing - Improved SINR or Improved Spectral Efficiency / Data Rates

46 Multi-Antenna Techniques Tx Diversity Transmit orthogonally modified redundant copies across multiple antenna s Robustness to channel fading / noise Tx0 Tx1 s0 -s1* s1 s0* Frequency domain Spatial Multiplexing Transmit different data streams simultaneously across multiple antenna s Improved spectral efficiency / throughput Tx0 Tx1 s0 s1 Beamforming Transmit per antenna weighted signal copies across multiple antenna s Coherent beamforming gain (db) at receiver Tx0 Tx1 S0,w0 S0,w1

47 LTE DL Transmission Modes 3GPP Release 8 TM1: TM2 : TM3: TM4: TM5: TM6: TM7: SISO single antenna transmissions Tx Diversity using 2 or 4 antennas Open-Loop SU-MIMO (Spatial Multiplexing) with CDD Closed-Loop SU-MIMO Closed-Loop MU-MIMO Closed-Loop, Rank 1 Spatial Multiplexing Rank 1 Spatial Multiplexing (Single-Layer Beamforming) Codebook based precoding 3GPP Release 9 TM8: Rank 2 Spatial Multiplexing (Dual-Layer Beamforming) Non-Codebook based precoding 3GPP Release 10 TM9: Up to 8 layer transmissions using Ports 7 to 14

48 MIMO in LTE 3GPP Release-8: Cell-specific RS MIMO/BF Downlink Based on Cell-specific RS (CRS) Transmitted on antenna ports 0 through 3 Support for up to 4x4 MIMO Transmit diversity or spatial multiplexing Codebook-based precoding Limited set of precoding matrices UE has to be informed of precoding layers antenna ports Layer mapper Precoding Cell-specific RS Resource element mapper Resource element mapper OFDM signal generation OFDM signal generation Reference: 3GPP TS Figure Overview of physical channel processing.

49 Single-User MIMO

50 MIMO in LTE 3GPP Release-9/10: UE-specific RS MIMO/BF Downlink Based on UE-specific RS (UE-RS) Transmitted on antenna port 5 (Single Layer transmission) TM7 Transmitted on antenna ports 7 & 8 (Dual Layer transmissions) TM8 Multi-User (MU) MIMO or Beamforming (BF) Non-codebook-based precoding UE-RS undergoes the same precoding. UE-RS is precoded same as PDSCH is. No need to inform UE of precoding. layers antenna ports Physical antennas Layer mapper UE-specific RS Precoding Resource element mapper Resource element mapper OFDM signal generation OFDM signal generation Beamforming weights UE-specific pattern Reference: 3GPP TS Figure Overview of physical channel processing.

51 8x2 Beamforming Modulation Analysis Example MIMO/BF Downlink

52 Agenda Introduction to LTE - Evolution and Motivation - Major features and requirements Air Interface Concepts - Frequency bands - OFDMA/SC-FDMA - Structure frame, slots, resource blocks - Physical signals and channels MIMO Concepts LTE-Advanced Major Features and Design Challenges - Carrier Aggregation - Enhanced Uplink Multiple Access (clustered SC-FDMA) - High Order MIMO - Other Study Items Question and Answer

53 3GPP UMTS Long Term Evolution 1999 Release Stage 3: Core specs complete Main feature of Release Rel-99 March 2000 UMTS 3.84 Mcps (W-CDMA FDD & TDD) Rel-4 March Mcps TDD (aka TD-SCDMA) Rel-5 June 2002 HSDPA Rel-6 March 2005 HSUPA (E-DCH) Rel-7 Dec 2007 HSPA+ (64QAM DL, MIMO, 16QAM UL). LTE & SAE Feasibility Study, Edge Evolution Rel-8 Dec 2008 LTE Work item OFDMA air interface SAE Work item New IP core network UMTS Femtocells, Dual Carrier HSDPA Rel-9 Dec 2009 Multi-standard Radio (MSR), Dual Carrier HSUPA, Dual Band HSDPA, SON, LTE Femtocells (HeNB) LTE-Advanced feasibility study, MBSFN Rel-10 March 2011 LTE-Advanced (4G) work item, CoMP Study Four carrier HSDPA Rel-11 Sept 2012 CoMP, edl MIMO, eca, MIMO OTA, HSUPA TxD & 64QAM MIMO, HSDPA 8C & 4x4 MIMO, MB MSR 2015 Rel-12 June -> Sept 2014 New carrier type, LTE-Direct, Active Antenna Systems, small cells Rel-13 Dec 2015 Just starting more CA

54 Comparing LTE, LTE-Advanced and IMT-Advanced Requirements Peak Data Rate Peak Spectrum Efficiency [bps/hz] Tx Bandwidth LTE 3GPP Release 8 LTE-Advanced IMT-Advanced 3GPP Release 10 International Telecommunications Union True 4G DL 300 Mbps 1 Gbps 100 Mbps UL 75 Mbps 500 Mbps (high mobility) 1 Gbps (low mobility) DL UL UL & DL Up to 20 MHz Up to 100 MHz Up to 40 MHz

55 LTE-Advanced and Beyond Features 1. Carrier aggregation 2. Enhanced uplink multiple access a) Clustered SC-FDMA b) Simultaneous Control and Data Rel-10 LTE-A 3. Enhanced multiple antenna transmission a) Downlink 8 antennas, 8 streams b) Uplink 4 antennas, 4 streams 4. Heterogeneous network support 5. Coordinated Multipoint (CoMP) 6. Relaying 7. Home enb mobility enhancements Other Rel-10 and beyond 8. Self organizing networks (SON)

56 1. What is Carrier Aggregation? Extends the maximum transmission bandwidth, up to 100 MHz, by aggregating up to five LTE carriers also known as component carriers (CCs) Lack of sufficient contiguous spectrum forces use of carrier aggregation to meet peak data rate targets: - 1 Gbps in the downlink and 500 Mbps in the uplink Motivation: - Achieve wide bandwidth transmissions - Facilitate efficient use of fragmented spectrum - Efficient interference management for control channels in heterogeneous networks Component Carrier (CC) up to 20 MHz BW Resource block

57 1. Carrier Aggregation Modes Component Carrier (CC) up to 20 MHz BW Resource block Band A f Intra -band contiguous allocation Resource block Band A f Intra-band non-contiguous allocation Resource block Band A Band B f Inter-band non-contiguous allocation

58 2. Enhanced Uplink Multiple Access Clustered SC-FDMA and Simultaneous PUCCH/PUSCH Multi-clustered SC-FDMA Maximum of 2 frequency-separated clusters for PUSCH transmission on a single component carrier. Simultaneous control (PUCCH) and data (PUSCH) transmission LTE Rel8/9 (Inherently single carrier) Partially allocated PUSCH f Lower PUSCH Upper PUSCH Fully allocated PUSCH LTE-Advanced Rel10 (Potentially in-channel multi-carrier) Partially allocated PUSCH + PUCCH Partially allocated Clustered-PUSCH + 2 PUCCHs Partially allocated Clustered-PUSCH Fully allocated PUSCH + 2 PUCCHs

59 Enhanced Uplink: Multi-Clustered SC-FDMA LTE 0 Subcarriers (resource blocks) are allocated contiguously PUSCH Modulation symbols Serial to parallel DFT Sub-carrier mapping 0 IFFT Parallel to Serial Add CP Tx SC-FDMA (contiguous resource allocation). Used in 3GPP Release 8 and 9 Subcarriers (resource blocks) are allocated in two clusters LTE-Advanced 0 PUSCH Modulation symbols Serial to parallel DFT Sub-carrier mapping 0 IFFT Parallel to Serial Add CP Tx 0 2 clusters Clustered SC-FDMA (non-contiguous resource allocation). Two clusters used in 3GPP Release 10 The difference between LTE and LTE-Advanced is at sub-carrier mapping block.

60 Enhanced Uplink: Simultaneous Control & Data Transmissions LTE 0 PUSCH (or PUCCH*) Modulation symbols Serial to parallel DFT Subcarrier mapping 0 IFFT Parallel to Serial Add CP Tx PUSCH or PUCCH transmission. Used in 3GPP Release 8 and 9 LTE-Advanced PUSCH Modulation symbols PUCCH * Modulation symbols Serial to parallel Serial to parallel DFT DFT Subcarrier mapping Simultaneous PUSCH and PUCCH transmission used in 3GPP Release 10 *only PUCCH Format 3 goes through DFT. PUCCH Formats 1 and 2 don t go through DFT 0 0 IFFT Parallel to Serial Add CP Tx PUSCH PUCCH

61 Enhanced Uplink: CCDF (PAPR) AWGN Comparable to Rel-8 (b) (c) (a) (d) Worse PAPR than Rel8; Still better than OFDMA

62 3. Enhanced Multiple Antenna Transmission Up to 8x8 Downlink (from 4x2 for Rel-8) Baseline being 4x4 with 4 UE Receive Antennae Peak data rate reached with 8x8 SU-MIMO Up to 4x4 Uplink (from 1x2 for Rel-8) New for LTE-A UE 1, 2 or 4 transmitters and 2, 4 or 8 receivers Baseline being 2x2 with 2 UE Transmit Antennae Peak data rate reached with 4x4 SU-MIMO Use of beamforming with spatial multiplexing to increase data rate, coverage and capacity Adds Downlink Transmission Modes 8 and 9 enodeb 2, 4 or 8 transmitters and 2, 4 or 8 receivers

63 LTE-Advanced and Beyond Features 1. Carrier aggregation 2. Enhanced uplink multiple access a) Clustered SC-FDMA b) Simultaneous Control and Data 3. Enhanced multiple antenna transmission a) Downlink 8 antennas, 8 streams b) Uplink 4 antennas, 4 streams Rel-10 LTE-A 4. Heterogeneous network support 5. Coordinated Multipoint (CoMP) 6. Relaying 7. Home enb mobility enhancements Other Rel-10 and beyond 8. Self organizing networks (SON)

64 4. Heterogeneous Networks Core Network Wireless Relay Fiber Optic Internet Pico/Micro Macro RRH/DAS Femto Pico/Micro Pico/Micro

65 5. Coordinated Multi-Point (CoMP) By coordinating transmission and reception among enbs co-located or across geographically separated locations (points) - it is possible to enhance network performance Multiple enbs cooperate to determine the scheduling, transmission parameters and transmit antenna weights for a particular UE Requires a high-capacity backhaul link as well as tight synchronization and time alignment between enbs CoMP operation can be divided into two: Coordinated scheduling/beamforming Joint processing

66 6. Relaying Basic in-channel relaying uses a relay node (RN) that receives, amplifies and then retransmits DL and UL signals to improve coverage RN is a network node connected wirelessly, via LTE air interface, to a source enb (donor enb) enb Over The Air backhaul RN Cell Edge enb Main use cases: Urban/indoor for throughput or dead zone Rural for coverage RN RN Multi-hop relaying Area of poor coverage with no cabled backhaul

67 7. Home enb Mobility Enhancements The concept of Home enb (femtocells) is not new to LTE-A In Release 8 femtocells were introduced for UMTS In Release 9 they were introduced for LTE (HeNB) In Release 10 further enhancements were added to enable HeNB to HeNB mobility This is very important for enterprise deployments

68 8. Self Organizing Networks (SON) Today s cellular systems are very much centrally planned, and the addition of new nodes to the network involves expensive and timeconsuming work, site visits for optimization, and other deployment challenges. The intent is to substantially reduce the effort required to introduce new nodes to the network. Examples of use cases : - Adding a new enb - Self configuration - Self Healing - Continuous optimization - Interference control - Capacity and coverage optimization

69 LTE-Advanced Deployment The first question to ask about LTE-A deployment timing is which feature LTE-A, Release 10, is a large grouping of backwards-compatible features, none of which are mandatory First to be deployed: - Some limited form of carrier aggregation to increase instantaneous bandwidth is particular local operator areas Example: US operator combining 10 MHz at 700 with 10 MHz at Uplink MIMO Requires two UE transmitters expensive, battery issues - Enhanced downlink MIMO for example 8x2

70 3GPP UMTS Long Term Evolution 1999 Release Stage 3: Core specs complete Main feature of Release Rel-99 March 2000 UMTS 3.84 Mcps (W-CDMA FDD & TDD) Rel-4 March Mcps TDD (aka TD-SCDMA) Rel-5 June 2002 HSDPA Rel-6 March 2005 HSUPA (E-DCH) Rel-7 Dec 2007 HSPA+ (64QAM DL, MIMO, 16QAM UL). LTE & SAE Feasibility Study, Edge Evolution Rel-8 Dec 2008 LTE Work item OFDMA air interface SAE Work item New IP core network UMTS Femtocells, Dual Carrier HSDPA Rel-9 Dec 2009 Multi-standard Radio (MSR), Dual Carrier HSUPA, Dual Band HSDPA, SON, LTE Femtocells (HeNB) LTE-Advanced feasibility study, MBSFN Rel-10 March 2011 LTE-Advanced (4G) work item, CoMP Study Four carrier HSDPA Rel-11 Sept 2012 CoMP, edl MIMO, eca, MIMO OTA, HSUPA TxD & 64QAM MIMO, HSDPA 8C & 4x4 MIMO, MB MSR 2015 Rel-12 June -> Sept 2014 New carrier type, LTE-Direct, Active Antenna Systems, small cells Rel-13 Dec 2015 Just starting more CA

71 RAN Work Items / Study Items per Release 300 number of RAN WIs/SIs after RAN # REL-9: : 4Q REL-10: : 5Q REL-11: : 6Q REL-12: : 8Q REL-13: : 5Q core WI perf WI test WI SI total total/rel length Fig. F-1: Number of all RAN work items (WI) and RAN study items (SI) in the different releases after RAN #63 (NOTE: An extension of REL-12 until Sep.14 is already included here.) The above figure from the RAN #63 report indicates the increasing fragmentation of the 3GPP radio standards. Rel-13 is just starting but will be shorter than Rel-12. More than half the activity in Rel-12 is carrier aggregation.

72 3GPP Standards Update R12 and Beyond Higher order modulation; 256QAM for DL Dual connectivity - Simultaneous connection to macro & small cell Ability to enable/disable small cells New carrier type (NCT) - The so-called lean carrier not backwards compatible with Rel-8/9. Less control channel overhead, can be switched on and off based on load Inter-cell synchronization via air interface Carrier aggregation - Aggregation of FDD & TDD spectrum - Aggregation of 3 Component Carriers Mobility & load balancing improvements between cellular & WiFi networks Additional SON enhancements UE-specific elevation beamforming / 3D-MIMO LTE-direct: Device to device discovery Device to device (D2D) communication LTE-Unlicensed focus on 5.8 GHz band

73 Agilent Solutions Across the Ecosystem for LTE/LTE-A Electronic system design software Vector signal analysis software Signal Analyzers with a variety of wireless Measurement Apps Signal Generators with Signal Studio software Scopes and Logic Analyzers LTE Signalling, RF, protocol and pre-conformance test platforms Pre-conformance Design Simulation Module and Chipset Development RF and BB Design Integration System Design Validation Conformance Manufacturing Protocol Development Deployment Widest bandwidth analysis for chipset design & verification Manufacturing test platforms Battery Drain Test Baseband generator and channel emulator RDX for DigRF v4 Interactive functional test SW Multi-channel signal analysis RF and Protocol Conformance test systems PXI solutions RF Handheld Analyzers

74 Agilent Tools to Help You Add Youtube videos Including Webcasts

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76 New Frequency Bands : Release 12 Three new FDD frequency bands will be defined: Band/Usage Uplink MHz Downlink MHz Width TBD/ITU Region TBD/Brazil TBD/US WCS Study Item Study item: - Currently widely allocated for satellite communications but terrestrial use now being considered, particularly for ITU Region 3 (Asia). - The potential for 110 MHz pairing with band 1 is also being considered.

77 Understanding 3GPP Release Structure The official scope of each 3GPP release is documented at: Each release has dates for the three main development stages - Stage 1: Service description from a service-user s point of view. - Stage 2: Logical analysis, breaking the problem down into functional elements and the information flows amongst them across reference points between functional entities. - Stage 3: is the concrete implementation of the protocols appearing at physical interfaces between physical elements onto which the functional elements have been mapped. And some less formal stages - Stage 0: Used to describe 3GPP feasibility studies (study items) - Stage 4: Used to describe the development of test specifications

78 Tracking Work Items and Study Items A complete list of 3GPP work items back to Release 99 can be found at Easy steps to find changed specifications for work items Click a Release (tabs at the top) Click a Feature or Study Item (on the left) See list of affected specifications: Click a unique ID # (UID) (on the left)