1 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Channel Configuration LTE Radio Parameters RL10 LTEPAR Pilot Dsseldorf CW 22 2010 & Reviewed

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4 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Module Contents Overview Generic DL Channels and signals UL Channels and Signals

5 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Overview - Channels Upper Layers RLC MAC PHY Logical channels Transport channels BCCH CCCH PCCH MTCH MCCH BCH PCH DL-SCH RACH UL-SCH PBCH PDSCH PHICH PDCCH PCFICH PMCH PUCCH PRACH PUSCH MCH CCCH DCCH DTCH ULDL Air interface DCCH DTCH

6 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use eNode B PDCCH PDSCH CQI, PMI, RI, ACK/NACK SR RNTI DL scheduling UL Grant UL PWRC n x per cell DL control configuration 1x per cell PCFICH PHICH HARQ Info PUSCHPUCCH CQI, PMI, RI, ACK/NACK Overview Control Information

7 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use 7 symbols (0.5 ms) 12subcarriers (180kHz) Symbol rate = 168 ksps QPSK => 2 bits per symbol => 336 kbps 16QAM => 4 bits per symbol => 672 kbps 64QAM => 6 bits per symbol => 1.008 Mbps Resource Block (RB) Basic unit of resource 12 subcarriers wide in the frequency domain 7 symbols long in the time domain Thus, 84 symbols per resource block Bit Rate per Resource Block depends upon modulation scheme Exercise - Theoretical RB Capacity (normal cyclic prefix case) Bit Rates per Resource Block Based upon 3GPP TS 36.211 TTI is 1 ms, i.e. duration of 2 resource blocks

8 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Channel Bandwidth 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz QPSK 2.016 5.040 8.400 16.800 25.200 33.600 16QAM 4.032 10.080 16.800 33.600 50.400 67.200 64QAM 6.048 15.120 25.200 50.400 75.600 100.800 64QAM (2+2 MIMO) 12.096 30.240 50.400 100.800 151.200 201.600 64QAM (4+4 MIMO) 24.192 60.480 100.800 201.600 302.400 403.200 Bit Rates per Resource Block Number of Resource Blocks These bit rates are applicable to the bottom of the Physical Layer, i.e. coding rate has not been taken into account Also requirement to account for the overheads generated by Reference and Synchronisation Signals + other Physical Channels Exercise - Theoretical LTE Bit Rates - Downlink Figures in Mbps

9 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use DL Physical Channels Allocation PBCH: Occupies the central 72 subcarriers across 4 symbols Transmitted during second slot of each 10 ms frame on all antennas PCFICH: Transmitted during the first symbol of each TTI Occupies up to 16 RE per TTI PHICH: Tx during 1st symbol of each TTI or alternativ during symbols 1 to 3 of each TTI PhichDur Each PHCIH group occupies 12 RE PDCCH: Occupies the REs not used by PCFICH and PHICH and Reference Signals within the first 1, 2 or 3 symbols of each TTI (case 1.4 MHz: within the first 2, 3 or 4 symbols) In RL09/10: configuration static by MaxNbrOfOFDMSymsForPDCCH PDSCH: Is allocated the RE not used by signals or other physical channels RB

10 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use UL Physical Channels PUSCH: Physical Uplink Shared Channel Intended for user data (carries traffic for multiple UEs) and control data If control data is to be sent when traffic data is being transmitted, UE multiplexes both streams together PUCCH: Physical Uplink Control Channel Carries H-ARQ Ack/Nack indications, uplink scheduling request, CQIs and MIMO feedback Only control information is sent. The UE uses Resources Element at the edges of the channel PRACH: Physical Random Access Channel For Random Access attempts. PDCCH indicates the resource elements for PRACH use PBCH contains a list of allowed preambles (64 per cell) and the required length of the preamble. RACH CCCH DCCH DTCH UL-SCH PRACH PUSCH PUCCH Logical Transport PHYS. RLC MAC

11 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Generic - Bandwidth Channel bandwidth: Bandwidths ranging from 1.4 MHz to 20 MHz Data subcarriers: They vary with the bandwidth 72 for 1.4MHz to 1200 for 20MHz Exercise: Describe bandwidths in terms of RBs

12 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Generic - Carrier Frequency and Bandwidth (FDD) 100 kHz ... ... FUL = FUL_low + 0.1(NUL NOffs-UL) FDL = FDL_low + 0.1(NDL NOffs-DL) Example (band 12) UL: 708 MHz = 698 MHz + 0.1 (23100 23000) MHz DL: 738 MHz = 728 MHz + 0.1 (5100 5000) MHz EARFCN NUL : earfcnUL NDL : earfcnDL Bandwidth UL: ulChBw DL: dlChBw

13 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Generic - Physical Layer Cell Id Physical Layer Cell Identity defines uniquely a cell. It consists of the two parts; Physical layer Cell Identity Group and Physical layer Identity Physical Layer Cell Identity = 3 x Physical layer Cell Identity Group + Physical layer Identity Decoded during synchronisation using primary and secondary sync signal Strongest Signal Primary Synchronization Signal Secondary Synchronisation Signal L1 id, slot (0/10) Physical Layer Cell ID, Frame Alignment Cell ID Group 0 (3 L1 ids) Group 167 Cell ID Group i (3 L1 ids)168 Cell ID groups Phy L Cell ID PSS/SSS are used for: Initial cell search and neighbor cell search As a result of cell search the UE should acquire: PHY cell ID DL center frequency 10ms and 5ms timing CP length Duplex mode (TDD/FDD)

14 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Generic - Time Structure (Frame Type 1) 19 144 Ts = 4.69 s 160 Ts CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol 512 Ts = 16.7 s CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol CP Symbol 1024 Ts = 33.3 s CP Symbol CP Symbol 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 0 Radio frame = 10 ms subframe = 1 ms Cyclic Prefix x2047-Ncp, x2047 Cyclic Prefix x2047-Ncp, x2047 OFDM Symbol (Time Domain Samples) x0, x1, , x2047 OFDM Symbol (Time Domain Samples) x0, x1, , x2047 Symbol Tsym = 2048 Ts = 66.67 sTcp = Ncp Ts f = 15 kHz, UL/DL - Extended Prefix f = 7.5 kHz, UL/DL - Extended Prefix f = 15 kHz, UL/DL - Normal Prefix Slot = 15360 Ts = 500s

15 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Generic Time Structure and CP length Short cyclic prefix: Long cyclic prefix: Copy= Cyclic prefix = Data 5.21 s 16.67 s Subframe length is 1 ms for all bandwidths Slot length is 0.5 ms 1 Subframe= 2 slots Slot carries 7 symbols with normal cyclic prefix or 6 symbols with extended prefix CP length depends on the symbol position within the slot: Normal CP: symbol 0 in each slot has CP= 160 x Ts (5.21s and remaining symbols CP= 144 x Ts ( 4.7s) Extended CP: CP length for all symbols in the slot is 512 x Ts ( 16.67s) Ts: sampling time of the overall channel. Basic Time Unit. Ts = 1 sec Subcarrier spacing X max FFT size Ts = 32.5nsec

16 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Generic: Parameters

17 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use DL - Channels and Signals Overview Upper Layers RLC MAC BCCH CCCH PCCH MTCH MCCH BCH PCH DL-SCH PBCH PDSCH PHICH PDCCH PCFICH PMCHMCH Air interface DCCH DTCH Synch RS PHY HI CFI DCI

18 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use 180 kHz 0.5 ms Secondary Synchronisation Signal (SSS) Primary Synchronisation Signal (PSS) DTX Slot id: 0 1 2 . . ..10.. ..19 0 1 Synch Signals Time and Frequency

19 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Synchronization Signals Detection Cell ID: One of 504 IDs detected from the index of PSS and the combination of two SSS segments CP length: Detected from the relative PSS-to-SSS time distance TDD/FDD: Detected from the relative PSS-to-SSS time distance 5ms timing: Detected from PSS time position 10ms timing: Detected from the interlaced SSS segments swapping:

20 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Reference Signals Common Reference Signals: Cell-specific FDM/TDMuxed Defined per antenna port F-density 6 sub-carriers (or 3 sub-carriers if staggered structure is considered) BW invariant mapping to REs Used for: Channel estimation (in case of CRS-based transmission with known/signaled precoding) Mobility measurements Auxiliary UE functions like: Time tracking Frequency tracking Cell ID verification CP length verification

21 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Incremental Time-Frequency Structure of Cell-specific Reference Signal Resource Element (RE) k, l Not used for transmission on this antenna port (DTX) Reference symbols (RS) on this antenna port l=0 ...... 6, 0 .. 6l=0 ...... 6, 0 .. 6 l=0 ...... 6, 0 .. 6 Antenna port 0 Antenna port 1 Antenna port 2 Antenna port 3 Fourantennaports

22 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use UE-specific Reference Signal Dedicated Reference Signals, support for DRS is mandatory for TDD and a UE capability for FDD: Used for single layer dedicated beamforming i.e. the same precoding applied on PDSCH and the DRS UE-specific FDM/TDMuxed with data Re-initialization period: each subframe Frequency-first mapping to REs

23 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Physical Broadcast Channel PBCH carriers essential system information like: DL BW configuration PHICH configuration System Frame Number (8 MBS bits) PBCH enables blind detection of: DL antenna configuration {1TX, 2TX, 4TX} via CRC masking 40 ms timing (2 LSB bits of SFN) via 40ms scrambling

24 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PBCH Structure Frequency: Occupies central 72 sub-carriers (excluding the DC) Time: TTI/scrambling period: 40ms Duration: first 4 OFDM symbols in slot #1 TBS: Fixed TB size of 40 bits (including 16 bit CRC) Transmission Scheme: QPSK, Tail Biting Convolutional Coding TX diversity: none, SFBC, SFBC-FSTD depending on the number of cell-specific antenna ports

25 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Physical Layer Downlink DL-Physical Data & Control Channels PBCPBC HH

26 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Physical Layer Downlink DL-Physical Data & Control Channels PCFICHPCFICH General Physical Control Format Indicator Channel (PCFICH) carries the CFI (Control Format Indicator) (Indicates the number of OFDM symbols used for transmission of control channel information in each subframe) Carriers dedicated to MBSFN have no physical control channel and therefore no PCFICH 4 code words defined 3 CFIs used and one reserved for future use (see table below) CFI CFI codeword 1 2 3 4 (reserved) Transmitted In the first OFDM symbol in a subframe The 32 bits of the CFI are mapped to 16 REs using QPSK modulation PCFICH is transmitted on the same antenna ports as the PBCH (1Tx, SFBC, SFBC-FSTD) Cell specific offset is added Cell specific scrambling

27 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Physical Control Format Indicator Channel (PCFICH) The PCFICH carries information about the number of OFDM symbols used for control signaling in a subframe Transmitted in the first OFDM symbol in a subframe with a target error probability of 10-3 The set of possible OFDM symbols for control signaling given in table Subframe Number of OFDM symbols for PDCCH and PHICH Subframe 1 and 6 for frame structure type 2 (TDD) 1,2 MBSFN subframes on a carrier supporting both PMCH and PDSCH 1,2 MBSFN subframes on a carrier not supporting PDSCH 0 All other subframes 1,2,3 (2,3,4 for 1.4 MHz)

28 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PCFICH Mapping to Resource Elements The mapping is done in terms of quadruplets of modulation symbols for each antenna port A quadruplet is defined as d(4i), d(4i+1), d(4i+2), d(4i+3) Reference symbols REs are always reserved for at least 2Tx antennas The four quadruplets shall be mapped to four resource element groups (REG) (aka mini-CCE) in the first OFDM symbol Example: 72 RB case (1.4 MHz): ( ) ( )DL RB cell ID RB sc 2mod2 NNNk = Starting position depends on cell id Distance between mini-CCEs Ant 0 Ant 1 frequency d0 d1 d2 d3 -d1 d0 -d3 d2 * * * * 22 RB sc DL RB NN Ant 0 Ant 1 frequency d0 d1 d2 d3 -d1 d0 -d3 d2 * * * * Ant 2 Ant 3 frequency Resour ce elemen t group

29 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PHICH For HARQ ACK/NACK signaling the PHICH is deployed. A PHICH is defined by its PHICH group number and an orthogonal sequence number within the group. PHICH modulation is BPSK. Applying I/Q separation and an SF=4 yields 8 orthogonal sequences for normal CP. SF 2 is in use in case of extended CP, hence there are 4 orthogonal sequences. I,e. in total there may be 8 .. 224 PHICHs in one subframe. Example:, BW=15 subcarriers normal CP, Ng=1/6, 1 PHICH group. 12 symbols are to be transmitted. They form a mapping unit which is further split in three quadruplets and mapped to REs as shown in the figure below NRB DL : DL BW / RBs Ng = 1/6, 1/2, 1, 2. setting: phichRes ( ) ( ) = prefixcyclicextendedfor82 prefixcyclicnormalfor8 DL RBg DL RBggroup PHICH NN NN N +j -j -j +j7 +j +j -j -j6 +j -j +j -j5 +j +j +j +j4 +j -j+1 -1 -1 +13 +j +j+1 +1 -1 -12 +1 -1+1 -1 +1 -11 +1 +1+1 +1 +1 +10 Extended CPNormal CP Orthogonal sequenceSequence Index +j -j -j +j7 +j +j -j -j6 +j -j +j -j5 +j +j +j +j4 +j -j+1 -1 -1 +13 +j +j+1 +1 -1 -12 +1 -1+1 -1 +1 -11 +1 +1+1 +1 +1 +10 Extended CPNormal CP Orthogonal sequenceSequence Index

30 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PHICH Association and Resource Indication PHICH duration: 1 or 3 OFDM symbols in normal subframes (indicated via PBCH) 1 or 2 OFDM symbols in MBSFN subframes and in DwPTS (Downlink Pilot Time Slot) PHICH linked to UL PRB Scattered grouping - spreads out the PHICH of adjacent PRBs to different PHICH groups When DM RS (Demodulation Reference Signal) CS (Cyclic Shift) index is configured in UL grant, use DMRS CS index as modifier to adjust PHICH allocation Avoid PHICH collision e.g. in case of UL MU-MIMO Balance power among PHICH groups PHICH indexing: Both index of the group and within the group depend on first UL PRB index and UL DM RS Cyclic Shift

31 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Physical Hybrid-ARQ Indicator Channel (PHICH) The PHICH carries the hybrid ARQ ACK/NACK corresponding to uplink transmissions Up to 8 Ack/Nacks (PHICHs) can be mapped to the same PHICH group separated by Walsh sequences A PHICH is identified uniquely by the index pair BPSK modulation Cell-specific scrambling and spreading with: Spreading Factor 4 for normal CP Spreading Factor 2 for extended CP The resulting sequence is mapped to 3 REGs by 3/6-fold repetition ( )seq PHICH group PHICH ,nn

32 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PDCCH Overview The PDCCH carries the UL and DL scheduling assignments A PDCCH is transmitted on an aggregation of one 1, 2, 4 or 8 control channel elements (CCE). A CCE consists of 36 REs The aggregations of CCEs have a tree structure, where an aggregation consisting of n CCEs starts on position (i mod n), where i is the CCE number Further restrictions on the aggregations are defined with a Hashing function described later Aggregation of 1 CCE Aggregation of 2 CCEs Aggregation of 4 CCEs Aggregation of 8 CCEs 0 1 102 3 4 5 6 7 8 9 11 12 13 14 15 16 17 18 19 2 0 21 2 2 23CCE number

33 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use DL - L1/L2 control info: PDCCH Resources The MaximumNumberOfOFDMSymbolsForPDCCH parameter defines how many OFDM symbols can be used. eNB selects the actual value for each TTI, which is signalled to UE in PCFICH. (Note, RL09 and RL10 uses fix allocation) Range: 1, 2, 3 (BW > 1.4 MHz); Range: 2, 3, 4 (BW = 1.4 MHz) setting: maxNrSymPdcch Example shows dynamic case for MaximumNumberOfOFDMSymbolsForPDCCH=3 (yellow)

34 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Physical Layer Downlink Summary DL-Physical Data & Control Channel DL-ChannelDL-Channel OverviewOverview

35 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Exercise: PDCCH Resources Task: Consider cell configuration: BW=50 PRB, 2 antenna ports, normal CP MaximumNumberOfOFDMSymbolsForPDCCH=2 Ng = 1/6 Calculate the number of available PDCCHs. Assume for frequency of occurancies of different aggregation levels (AL) AL4 is 2 times the frequency of AL8 AL2 is 2 times the frequency of AL4 AL1 is 1/2 times the frequency of AL2

36 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Solution: PDCCH Resources Task: Consider cell configuration: BW=50 PRB, 2 antenna ports, normal CP MaximumNumberOfOFDMSymbolsForPDCCH=3 Ng = 1/6 Calculate the max number of PDCCHs. Solution: - 1st symbol yields 2 RBGs per PRB x 50 PRB = 100 RBGs - 2nd yields each 3 x 50 = 150 RBGs. Total: 250 RBGs. - 4 RBGs for PCFICH, 2x3=6 for PHICH 240 RBGs remain for PDCCH - 390 div 9 = 26 CCEs are available - For 1 distribution 1xAL8 + 2xAL4 + 4xAL2+2xAL1 - Aggregation level 8 1x = 8 CCEs - Aggregation level 4 2x = 8 CCEs - Aggregation level 2 4x = 8 CCEs - Aggregation level 1 2x = 2 CCEs 26 CCEs are consumed for 9 PDCCH. Note: due to allocation constraints some might be blocked

37 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PDCCH Multiplexing and Scrambling PDCCH is FEC encoded and aggregated (rate matched) to 1, 2, 4 or 8 CCEs The PDCCHs are concatenated, possible with CCE holes in between due to placement restrictions. Unspecified bits are added so that the PDCCHs occupy the whole space reserved for PDCCH transmission The block of bits are scrambled with a cell-specific Gold code FEC and rate matching CCEs Scrambli ng PDCCHs CCE aggregation PDCCH0 PDCCH1 PDCCH2 PDCCH3 Unspecifi ed bits PDCCH4 Unspecified bits PDCCH5Unspecified bits

38 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PDCCH Mapping to Resource Elements The block of quadruplets for each antenna port is permuted with the sub-block interleaver, where interleaving is done on symbol quadruplets The block of permuted quadruplets are then cyclically shifted The quadruplets are cyclically shifted and finally mapped to resource element groups (aka mini-CCEs), which have not been allocated to a PCFICH or a PHICH, in a time first order. Example mapping for 2 TX: 1 2 3 4 5 6 7 8 frequen cy time RS REG

39 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Downlink Control Information (DCI) A DCI transports control information for one MAC ID, which is implicitly signaled in the CRC. Format 0 Used for defining the transmission of PUSCH assignments Format 1 Used for defining the transmission of PDSCH assignments for single codeword (SCW) operation Format 1A Compact form for the transmission of PDSCH assignments for SCW operation. Has same size as format 0 Format 1B Compact form like 1A but supports closed-loop rank 1 precoding Format 1C Signaling for PCH, RACH and BCCH on DLSCH (aka dynamic BCCH) Format 1D Like DCI 1A but supports power offsets for DL MU-MIMO and TPMI Format 2 Used for defining the transmission of DL-SCH assignments for Closed-Loop MIMO operation Format 2A Used for defining the transmission of DL-SCH assignments for Open-Loop MIMO operation Format 3 Used for TPC commands for PUCCH and PUSCH with 2-bit power adjustments. Has same size as format 0 Format 3A Used for TPC commands for PUCCH and PUSCH with 1-bit power adjustments. Has same size as format 0

40 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use DCI Format 1 Control information for 10 MHz BW for FDD, 1TX/TxDiv Fields for Format 1 Bits Comments Resource allocation header 1 Indicates resource allocation type 0 or 1 RB allocation 17 Resource allocation type 0 or 1 MCS 5 Hybrid ARQ process number 3 3 for FDD, max 4 for TDD New data indicator 1 Toggled for each new transport block Redundancy version 2 TPC 2 Power control of PUCCH RNTI / CRC 16 16 bit RNTI implicitly encoded in CRC Total 47

41 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Format 1A Compact control information for 10 MHz BW for FDD, 1Tx/TxDiv Fields for Format 1A Bits Comments Format 1 Uplink grant or downlink assignment (Flag for format0/format1A differentiation) Distributed transmission 1 RB assignment 12 Resource allcation type 2 MCS 5 Hybrid ARQ process number 3 (4 bits for TDD) New data indicator 1 Toggled for each new transport block Redundancy version 2 {0, 1, 2, 3} TPC 2 Power control of PUCCH RNTI / CRC 16 16 bit RNTI implicitly encoded in CRC Total 43

42 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Format 2 Control information for 10 MHz BW, SU-MIMO Fields for format 2 Bits Comment Resource allocation header 1 Indicates allocation type 0 or 1 RB allocation 17 Resource allocation type 0 or 1 TPC 2 Power control of PUCCH Hybrid ARQ process number 3 3 for FDD, max 4 for TDD HARQ swap flag 1 Indicates whether the two transport blocks should be swapped before being mapped to codewords MCS, first transport block 5 New data indicator (1st TB) 1 Toggled for each new transport block Redundancy version (1st TB) 2 MCS, second transport block 5 New data indicator (2n TB) 1 Toggled for each new transport block Redundancy version (2nd TB) 2 Precoding information 3-6 3 bits for 2 Tx, 6 bits for 4 Tx. This field is jointly coded with PMI, rank indicator and PMI report indicator. For open loop MIMO 0 or 2 bits are used for the 2Tx and 4Tx cases respectively RNTI / CRC 16 Total 59 For closed loop MIMO 2 Tx FDD

43 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PDCCH Blind Detection The UE is required to blindly decode the control region in order to find a PDCCH with its own RNTI or common RNTIs Max. number of 44 blind decoding trials per subframe Because the total number of potential PDCCHs is very high a hashing function is used to assign the CCEs that a UE shall monitor Common search space (CSS): Two DCI sizes are possible in CSS: DCI 0/1A/3/3A and DCI 1C UE specific search space (USS): Each UE will additionally monitor a set of control channel candidates at each aggregation level. Two DCI sizes are possible in USS DCI 0/1A and DCI 1/1B/2/2A1D Search space CCE Aggregation level Size in CCEs # of PDCCH candidates UE- specific 1 6 6 2 12 6 4 8 2 8 16 2 Common 4 16 4 8 16 2

44 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use DL L1/L2: Exercise x x x x x x x x x x Indicate PHICH and the other DL phys. channels / signals. Which value is used for Ng, 1/6, 1/2, 1, 2 ?

45 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use DL L1/L2 - Parameters

46 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use UL Channels The mapping of transport channels and UL control information (UCI) to physical channels is a task of the physical layer (PHY). Furthermore reference signals are provided by the physical layer which do not transfer any higher layer information. Logical channel mapping is provided by the MAC layer. Physical channel for data and signalling from higher layers: Physical Uplink Shared Channel, PUSCH. Physical Random Access Channel, PRACH. Physical channels with UL control - related signalling: Physical Uplink Control Channel, PUCCH. and signals with no information of higher layers: Demodulation Reference Signals (DRS). Sounding Reference Signal (SRS).

47 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use UL Channel Mapping Upper Layers RLC MAC PHY RACH CCCH DCCH DTCH Air interface PRACH PUSCHUL-SCH PUCCH UCI DRS SRS

48 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use UE Channel state information (CSI) feedback types in LTE The purpose of CSI feedback is to provide the eNodeB information about DL channel state to help in the scheduling decision. Compared to the WCDMA/HSPA, the main new feature in the channel feedback is the frequency selectivity of the report CSI is measured by the UE and signaled to the eNodeB using PUCCH or PUSCH Channel state information in LTE can be divided into three categories: CQI - Channel Quality Indicator RI - Rank Indicator PMI - Precoding Matrix Indicator In general the CSI reported by the UE is just a recommendation The eNodeB does not need to follow it The corresponding procedure for providing information about the UL channel state is called Channel Sounding and it is done using the Sounding Reference Symbols, SRS (not considered in this presentation) (1) eNodeB transmission (3) UE feedback (2) UE CSI measurement

49 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Channel Quality Indicator (CQI) The most important part of channel feedback is the CQI The CQI is defined as a table containing 16 entries with modulation and coding schemes (MCSs) The UE shall report back the highest CQI index corresponding to the MCS for which the transport block BLER shall not exceed 10% CQI index modulatio n coding rate x 1024 efficiency 0 out of range 1 QPSK 78 0.1523 2 QPSK 120 0.2344 3 QPSK 193 0.3770 4 QPSK 308 0.6016 5 QPSK 449 0.8770 6 QPSK 602 1.1758 7 16QAM 378 1.4766 8 16QAM 490 1.9141 9 16QAM 616 2.4063 10 64QAM 466 2.7305 11 64QAM 567 3.3223 12 64QAM 666 3.9023 13 64QAM 772 4.5234 14 64QAM 873 5.1152 15 64QAM 948 5.5547

50 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use CQI Measurement The CQI report transmitted in the uplink subframe n+4 corresponds to the reference period of the downlink subframe n for FDD. This ensures that the UE has always at least 2.33 ms processing time for the CQI measurement

51 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Rank Indicator (RI) Rank Indicator is only relevant when the UE is operating in MIMO modes with spatial multiplexing For single antenna operation or TX diversity it is not used RI is the UEs recommendation for the number of layers to be used in spatial multiplexing The RI can have values {1 or 2} with 2-by-2 antenna configuration and {1, 2, 3, or 4} with 4-by-by antenna configuration The RI is always associated to one or more CQI reports

52 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Precoding Matrix Indicator (PMI) PMI provides information about the preferred Precoding Matrix Just like RI, also PMI is relevant to MIMO operation only MIMO operation with PMI feedback is called Closed Loop MIMO Example: codebook for 2 TX antennas

53 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Periodic and Aperiodic reporting The channel feedback reporting in LTE is divided into two main categories: Periodic and Aperiodic Periodic reporting The baseline mode for CQI/PMI/RI transmission is periodic reporting on PUCCH If the UE is scheduled to send UL data in the subframe where it should transmit periodic CQI/PMI/RI, the periodic report is moved to PUSCH and multiplexed with data The eNodeB configures the periodicity parameters The size of a single report is limited up to about 11 bits depending on the reporting mode Limited amount of frequency information Aperiodic Reporting Aperiodic reports are explicitly triggered by the eNodeB using a specific bit in the PDCCH UL grant Aperiodic report can be either piggybacked with data or sent alone on PUSCH Possibility for large and detailed reports (up to more than 60 bits) The two modes can also be used to complement each other: - The UE can be e.g. configured to send Aperiodic reports only when it is scheduled, while periodic reports can provide coarse channel information on a regular basis

54 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use CQI compression schemes (1/2) Compared to the WCDMA/HSPA, the main new feature in the channel feedback is the frequency selectivity of the report This is an enabler for the Frequency Domain packet Scheduling (FDPS) Since providing a full 4-bit CQI for all the PRBs would mean excessive UL signaling overhead, some feedback compression schemes are used In order to reduce feedback, the CQI is reported per subband basis The size of the subbands varies depending on the reporting mode and system bandwidth The main compression methods are: Wideband feedback Best-M average aka UE selected subband feedback Full Feedback aka Higher Layer Configured subband feedback Additionally, Delta compression can be used E.g. in MIMO case the CQI for the 2nd Code Word can be signaled as a 3-bit delta relative to the CQI of the CQI of the 1st CW

55 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use CQI compression schemes (2/2) Wideband feedback Only a single CQI value is fed back for the whole system band Cannot be utilized in FDPS Best-M average aka UE selected subband feedback For the M best subband an average CQI value is reported Full Feedback aka Higher Layer Configured subband feedback A separate CQI is reported for each subband using Delta compression An example of Best-M Average reporting with 3 MHz BW M = 3 best Subbands are selected and an average CQI value is reported Channel SINR Subband index 1 2 3 4 5 6 7 8 PRB index 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

56 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use CQI periodic reporting on PUCCH Wideband feedback or UE selected subband Period configurable 2, 5, 10, 16, 32, 40, 64, 80, 160 ms, off A single CQI result per report Best subband per BW part Configured by higher layer signalling BW / RB Subband Size k BW Parts (J) 6-7 NA NA 8-10 4 1 11-26 4 2 27-63 6 3 64-110 8 4

57 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Categorization of CQI/PMI/rank reporting options LTE CQI reporting family tree Periodic Frequency selective Aperiodic Single CQI Full FeedbackBest-M Average No PMI Mode 2-0 24 bits No PMI Mode 3-0 30 bits Multi PMI 1-2 60 bits Single PMI Mode 3-1 64 bits Multi-PMI Mode 2-2 38 bits Wideband No PMI Mode 2-0 6 bits Single PMI Mode 2-1 11 bits No PMI Mode 1-0 4 bits Single PMI Mode 1-1 11 bits Single or Multi-PMI = closed loop MIMO with PMI feedback No PMI = Single antenna, TxDiv or OL MIMO The maximum number of feedback bits for each option Assuming 20 MHz BW and 4*4 CL MIMO is listed excluding RI - With Periodic reporting RI is sent in separate subframes with potentially larger periodicity - In Aperiodic reporting The RI is separately coded with each CQI/PMI report

58 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PDCCH Uplink Grant The eNodeB allocates the Uplink resources to the UEs by sending an UL Grant UL Grant contents Resource Block assignment Indicates the PRB the UE may use for transmission Signaling format: index of starting PRB & number of contiguous PRBs Modulation and Coding Scheme and the Redundancy version (5 bits) Power control command (2 bits) Cyclic Shift for the demodulation reference symbols CQI request flag PUSCH Hopping flag New data indicator TDD specific UL index (indicates which UL subframe the grant refers to) Downlink assignment index

59 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Zadoff-Chu sequences Zadoff-Chu sequences are used as UL demodulation and sounding reference signals random access preamble sequence DL primary synchronization signal ZC sequences are CAZAC (constant amplitude zero autocorrelation) sequences Low cubic metric and flat frequency response The elements of ZC sequence are points from unit circle It is possible to create ZC sequences of any length with relatively simple formulas Depending on sequence length different number of base/root sequences can be formed Sequence with prime number of elements is optimal Root sequence can be considered as circular. Different cyclic shifts of a root sequence can be obtained by changing the starting element Cyclic shift must larger than time ambiguity of received sequence

60 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use UL DM RS The good cross correlation properties of ZC sequences are only applicable between sequences of the same length Cells of the same eNB may have coordination in scheduling but generally it can not be assumed that UL allocations in the neighboring cells are the same When UL allocations are not coordinated high cross correlations are possible between UEs in neighboring cells In order to average the cross correlations, DM RS sequences change between slots. Both root sequence and cyclic shift can change when group hopping/sequence hopping and cyclic shift hopping are used Cell A Cell B Cell C freq UE 1 UE 2 UE 3 Orthogonal DM RS High cross- correlation

61 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Uplink Control Signaling: PUCCH vs. PUSCH PUCCH (Physical Uplink Control Channel) Used when the UE is not sending data simultaneously Shared frequency and time resource reserved exclusively for the UEs transmitting only L1/L2 control signals Optimized for large number of simultaneous UEs with relatively small number of control signaling bits per UE (111) Very high multiplexing capacity, spectral efficiency e.g. 18 UEs/RB transmitting ACK/NACK (PUCCH Format 1a/1b) 6 UEs/RB transmitting 11-bit CQI + 2-bit A/N (PUCCH Format 2b) PUSCH (Physical Uplink Shared Channel) Used when the UE transmits also data UE-specific resource that can be used for L1/L2 control signaling (based on scheduling decisions made by Node B) Capable to transmit control signals with large range of supported control sizes (1 64 bits) TDM between control and data (multiplexing is made prior DFT) Single carrier limitations: Simultaneous transmission of PUCCH and PUSCH is not allowed. Separate control resources for the cases with and without UL data are required

62 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PUCCH, basics PUCCH (from single-UE perspective) Frequency resource of one RB Time resource of one sub-frame (A/N repetition is also supported) Slot based frequency hopping is always used It provides the sufficient degree of frequency diversity Hopping takes place on the band edges, symmetrically over the center frequency Multiplexing between UEs FDM btw RBs CDM inside the RB slot system bandwidth Resource block PUCCH

63 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PUCCH, UE Multiple Access Within a RB UEs are separated using of CDM (within an RB) Two orthogonal CDM techniques are applied on PUCCH CDM using cyclic shifts of CAZAC* sequence CDM using block-wise spreading with the orthogonal cover sequence Multiplexing example: PUCCH Format 1/1a/1b (e.g., A/N) Both CDM techniques are in use -> 18 parallel resources *) The applied sequences are not true CAZAC but computer searched Zero-Autocorrelation (ZAC) sequences RS RS RS slot SF=3 SF=4 Cyclic Orthogonal cover code shift 0 1 2 0 0 12 1 6 2 1 13 3 7 4 2 14 5 8 6 3 15 7 9 8 4 16 9 10 10 5 17 11 11 block-wise spreading CDM in CS domain

64 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PUCCH Formats (1/2) Format 1/1a/1b Length-12 CAZAC sequence modulation + block-wise spreading Format 2/2a/2b Length-12 CAZAC sequence modulation PUCCH formats Control type PUCCH Format 1 Scheduling request PUCCH Format 1a 1-bit ACK/NACK PUCCH Format 1b 2-bit ACK/NACK PUCCH Format 2 CQI PUCCH Format 2a CQI + 1-bit ACK/NACK PUCCH Format 2b CQI + 2-bit ACK/NACK

65 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Scheduling request (SR) Scheduling Request mechanism is used for the active mode UEs having no valid UL grant for PUSCH available UE can indicate the need to transmit UL data by sending a SR Non-contention based: a distinct SR resource is given to each UE Scheduling request indicator (SRI) utilizes PUCCH Format 1: 2 states, On-off keying: only positive SR is transmitted SR scheme is compatible with the ACK/NACK structure Multiplexing capacity: 18 UEs/sub-frame (every second CS used)

66 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Mapping of logical PUCCH resources into physical PUCCH resources m=1 m=0 m=3 m=2 m=2 m=3 m=0 m=1 slot system bandwidth PUCCH Periodic CQI is located at the outermost RBs These resources are allocated explicitly via RRC SR and persistent A/N are next to Periodic CQI These resources are allocated explicitly via RRC Dynamic A/N is located at the innermost PUCCH RBs Allocated implicitly based on PDCCH allocation

67 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Capacity of PUCCH resources 6 CS 6 UEs (12 CS 12 UEs) 10 msec period, 2 RB total 120 UEs (240) 6 CS & 3 cover codes 18 UEs 5 msec period, 2 RB total 180 UEs Configuration example: 6 CS & 3 cover codes 18 Ues per subframe Frame (10 msec) RB (180 kHz) PUSCH

68 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Control signaling on PUSCH (1/2) TDM multiplexing between control and data Data and the different control fields (ACK/NAK, CQI/PMI) are mapped to separate modulation symbols Separate coding btw data and control Separate coding btw different control fields Same gain factor for control and data Control modulation CQI utilizes the same modulation as data ACK/NACK is transmitted always using QPSK constellation Outermost constellation points are selected in the case of 16QAM/64QAM MUX DFT IFFT CP Data symbols CQI symbols ACK/NACK symbols

69 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Control signaling on PUSCH (2/2) Time-first mapping for CQI CQI resources are placed at the beginning of the SC-FDMA Symbols ACK/NACK is placed at the end of the SC-FDMA symbols RI+data AN+data DM RS AN+data RI+data RI+data AN+data DM RS AN+data RI+data slot #1 slot #2 Control and data multiplexing is performed in such that control is present on both slots of the subframe ( FH gain when available) ACK/NACK is placed next to RS (at maximum 2 blocks/slot for A/N) Rank indicator is placed next to the A/N (at maximum 2 blocks/slot for RI)

70 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Channel coding for UL control information PUCCH Format 1/1a/1b: repetition coding only PUCCH Format 2/2a/2b, CQI: Block coding, (20, N) PUSCH 1-bit ACK/NACK or RI: repetition coding only 2-bit ACK/NACK or RI: simplex coding 411 bit CQI: Block coding, (32, N) CQI>11 bits: Tail-biting convolutional coding (1/3), CRC

71 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Sounding reference signal PRB sub- framei i +1 1 1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 PUSCH (scheduled) PUSCH (persistent) DM RS PUCCH SRS Cell specific SRS bandwidth Transmission from one UE (example) SRS is used to assist frequency dependent scheduling Wide BW signal or frequency hopping/scanning can be used to obtain info about channel characteristics outside current PUSCH frequencies Zadoff-Chu sequences are used. UEs can be multiplexed to same resources by Interleaved FDMA (every other subcarrier is used by one UE) Different cyclic shifts SRS can also be used as reference for timing advance measurements. Low periodicity is sufficient in this case NOT IN RL10

72 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Sounding Reference Signal The sequence index is derived from the PUCCH base sequence index. The cyclic shift is signalled to the UE. SRS bandwith depends on the cell bandwith and the configuration. Frequency hopping can be deployed. Every second RE in frequency domain is transmitted. Not transmitted if PUCCH is needed. For RL09 and RL10: SRS n/a NOT IN RL10

73 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use CQI Reporting - Parameters

74 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use PUCCH - Parameters

75 Nokia Siemens Networks LTE Radio Parameters / v001 / Document Number For internal use Sounding Reference Signal - Parameters