12 initial parameter planning gc

1 © Nokia Siemens Networks RA4120BCEN20GLA0

LTE RPESSInitial Parameter Planning

3 © Nokia Siemens Networks RA4120CEN20GLA0

Module Objectives

After completing this module, the participant should be able to:

• Describe the concept of channel configuration parameters• Understand the PRACH configuration parameters• Understand the PCI configuration parameters• Understand the UL DM & RS configuration parameters• Understand the PDCCH capacity & parameters• Understand the PUCCH capacity & parameters


Initial Parameter Planning

PRACH Planning PCI Planning UL DM RS Planning PDCCH Dimensioning PUCCH Dimensioning


PRACH PlanningPrinciple

PRACH configuration: two cells must be different within the PRACH re-use distance to increase the RACH decoding success rate

PRACH transmission can be separated by:• Time (prachConfIndex)

– PRACH-PUSCH interference: If PRACH resources are separated in time within eNB– PRACH-PRACH interference: If same PRACH resources are used for the cells of an eNodeB. – PRACH-PRACH interference is preferred to PRACH-PUSCH interference so prachConfIndex of the cells

on one site should be the same

• Frequency (prachFreqOff)– Allocation of PRACH area should be next to PUCCH area either at upper or lower border of frequency

band, however should not overlap with PUCCH area– Avoid separation of PUSCH in two areas by PRACH (The scheduler can only handle one PUSCH area)– For simplicity use same configuration for all cells

• Sequence (PRACH CS and RootSeqIndex)– Use different sequences for all neighbour cells


Preamble Formats

• 3GPP (TS36.211) specifies 4 random access formats for FDD

• Difference in formats is based in the different durations for the cyclic prefix, sequence and guard time which have an effect on the maximum cell radius

• Formats 0 and 1 are supported in RL30 Recommendation:

Select Format0 for cell ranges <14.53 km

Select Format1 for cell ranges <77.34 km


PRACH Configuration IndexprachConfIndex

• The parameter defines the Allowed System Frame for random access attempts, the Sub-frame numbers for random access attempts and the Preamble format

• Supported values:– For Preamble Format 0: 3 to 8– For Preamble Format 1: 19 to 24

• RACH Density indicates how many RACH resources are per 10ms frame.

• Only RACH density values of 1 and 2 are supported .E.g.

– RACH density=1 Only one random access attempt per frame

– RACH density=2 Two random access attempts per frame

Extract of the random access preamble configurations table (only for supported preamble formats 0 and 1)

Recommendation: Configure the same PRACH configuration Indexes at

cells belonging to the same site. E.g.: 3 or 4 or 5 if RACH density=1 and 6 or 7or 8 if RACH

density=2 (Preamble Format 0)prachConfIndexLNCEL; 3..24;1; 3 (Range; Step; Default)

Range is restricted to two different ranges: 3-8 and 19-24 (internal)


PRACH Frequency OffsetprachFreqOff

• Indicates the first PRB available for PRACH in the UL frequency band• PRACH area (6 PRBs) should be next to PUCCH area either at upper or lower border of frequency

band to maximize the PUSCH area but not overlap with PUCCH area• Parameter is configured based on the PUCCH region (see PUCCH dimensioning) i.e. its value

depends on how many PUCCH resources are available.• If PRACH area is placed at the lower border of UL frequency band then:

PRACH_Frequency Offset= roundup [PUCCH resources/2]

• If PRACH area is placed at the upper border of the UL frequency band then:

PRACH_Frequency Offset= NRB -6- roundup [PUCCH resources/2]

NRB: Number of Resource Blocks

prachFreqOffFirst PRB available for PRACH in UL

LNCEL; 0...94;1; -

Max. value is ulChBw(in PRB) - 6


PRACH Cyclic ShiftPrachCS

• PrachCS defines the configuration used for the preamble generation. i.e. how many cyclic shifts are needed to generate the preamble

• PrachCS depends on the cell size – Different cell ranges correspond to different PrachCS

• Simplification: To assume all cells have same size (limited by the prachConfIndex)

Recommendation: Select PrachCS based on the cell range E.g. if

estimated cell range is 15km then PrachCS: 12 If all cells in the network are assumed to have

same cell range then PrachCS is the same network wise

prachCSPreamble cyclic shift (Ncs configuration)

LNCEL;0…15;1; 12


PrachCS and rootSeqIndex

• PrachCS defines the number of cyclic shifts (in terms of number of samples) used to generate multiple preamble sequences from a single root sequence

• Example based on PrachCS=12 -> number of cyclic shifts: 119

– Root sequence length is 839 so a cyclic shift of 119 samples allows ROUNDDOWN (839/119)= 7 cyclic shifts before making a complete rotation (signatures per root sequence)

• 64 preambles are transmitted in the PRACH frame. If one root is not enough to generate all 64 preambles then more root sequences are necessary

– To ensure having 64 preamble sequences within the cell it is necessary to have ROUNDUP (64/7)= 10 root sequences per cell

rootSeqIndexLNCEL;0…837;1; 0


PRACH Cyclic ShiftrootSeqIndex

• RootSeqIndex points to the first root sequence to be used when generating the set of 64 preamble sequences.

• Each logical rootSeqIndex is associated with a single physical root sequence number.

• In case more than one root sequence is necessary the consecutive number is selected until the full set is generated

Logical root sequence number

Physical root sequence index (in increasing order of the corresponding logical sequence number)

0–23 129, 710, 140, 699, 120, 719, 210, 629, 168, 671, 84, 755, 105, 734, 93, 746, 70, 769, 60, 779

2, 837, 1, 838

24–29 56, 783, 112, 727, 148, 691

30–35 80, 759, 42, 797, 40, 799

36–41 35, 804, 73, 766, 146, 693

42–51 31, 808, 28, 811, 30, 809, 27, 812, 29, 810

52–63 24, 815, 48, 791, 68, 771, 74, 765, 178, 661, 136, 703

…. …..

64–75 86, 753, 78, 761, 43, 796, 39, 800, 20, 819, 21, 818

810–815 309, 530, 265, 574, 233, 606

816–819 367, 472, 296, 543

820–837 336, 503, 305, 534, 373, 466, 280, 559, 279, 560, 419, 420, 240, 599, 258, 581, 229, 610

Extract from 3GPP TS 36.211 Table 5.7.2.-4 ( Preamble Formats 0-3). Mapping between logical and physical root sequences.

Recommendation: Use different rootSeqIndex across neighbouring cells means to ensure neighbour cells will use different preamble sequences

rootSeqIndexLNCEL;0…837;1; 0


PRACH PlanningWrap Up

Steps: 1. Define the prachConfIndex

• Depends on preamble format (cell range)• It should be the same for each cell of a site

2. Define the prachFreqOff• Depends on the PUCCH region• It can be assumed to be the same for all cells of a network (simplification)

3. Define the PrachCS• Depends on the cell range• If for simplicity same cell range is assumed for all network then prachCS is the same for all cells

4. Define the rootSeqIndex• It points to the first root sequence • It needs to be different for neighbour cells• rootSeqIndex separation between cells depends on how many are necessary per cell (depends

on PrachCS)


Exercise

• Plan the PRACH Parameters for the sites below:

• Assumptions:– PUCCH resources =6– Cell range = 12km (all cells have same range)– BW:10MHz

Sites Cell Azimuth PrachConfIndex PrachFreqOff PrachCs rootSeqIndex

A1 0 2 120 3 240

B1 0 2 120 3 240

C1 0 2 120 3 240

D1 0 2 120 3 240

E1 0 2 120 3 240


Solution (1/3)

Steps: 1. Define the prachConfIndexCell Range is 12 Km therefore Format 0 is plannedFor start RACH density 1 is selectedTherefore: prachConfIndex = 3, for example the same in all the cells

2. Define the prachFreqOffWe assume that PRACH area is placed at the upper border of the UL frequency band then:

PRACH-Frequency Offset= NRB -6- roundup [PUCCH resources/2]

(NRB = 50 for 10 MHz (1...50) & PUCCH resources = 6)

prachFreqOff = 50 – 6 – roundup[6/2] = 41


Solution (2/3)

Steps: 3. Define the prachCsCell range is 12 Km therefore the prachCS = 11In this case there are 93 cyclic shifts to generate thepreambles and 9 signatures per root sequence

4. Define the rootSeqIndexThere are in total 838 root sequences There are 8 root signatures required per cellThe planning could be done to allocate therootSeqIndex per clusterWe assume that the planned cells in the example are beloning to one clusterIn this way the first cell is taking the rootSeqIndex= 0..7, the second cell 8..15, the third cell 16..23 and

so on


Solution (3/3)

• The final planning below:

• Assumptions:– PUCCH resources =6– Cell range = 12km (all cells have same range)– BW:10MHz

Sites Cell Azimuth PrachConfIndex PrachFreqOff PrachCs rootSeqIndex

A1 0 3 41 11 02 120 3 41 11 83 240 3 41 11 16

B1 0 3 41 11 242 120 3 41 11 323 240 3 41 11 40

C1 0 3 41 11 482 120 3 41 11 563 240 3 41 11 64

D1 0 3 41 11 722 120 3 41 11 803 240 3 41 11 88

E1 0 3 41 11 962 120 3 41 11 1043 240 3 41 11 112


PCI PlanningIntroduction

• There are 504 unique Physical Cell IDs (PCI) Physical Layer Cell Identity = (3 × NID1) + NID2

NID1: Physical Layer Cell Identity group. Range 0 to 167– Defines SSS sequence

NID2: Identity within the group. Range 0 to 2– Defines PSS sequence

Resource element allocation to the Reference Signal

• PCI impacts the allocation of resource elements to the reference signal and the set of physical channels

• Allocation pattern repeats every 6th Physical Layer Cell Identity

phyCellId:Physical Cell IdLNCEL; 0..503; 1; - (Range; Step; Default)


PCI Planning

• Analogous to scrambling code planning in UMTS– Maximum isolation between cells with the same PCI

▪ To ensure that UE never simultaneously receive the same identity from more than a single cell• Physical Cell Identity is defined by the parameter phyCellID:

Parameter Object Range Default

phyCellId LNCEL 0 to 503 Not Applicable

• There should be some level of co-ordination across international borders when allocating PCIs. – This will help to avoid operators allocating the same identity to cells on the same RF carrier and in

neighbouring geographic areas


Physical Cell identification and Global Cell ID identification

Physical Layer Cell ID (PCI)

Global Cell ID (ECGI)

7777

• The sequence to generate the Reference Signal depends upon the PCI• Short repetition cycle of 1 ms• Limited to 504 values so not unique• Careful assignment needed because a UE shall never receive the

same value from 2 different cells

• E-UTRAN Cell Global identifier• Part of SIB 1• SIB 1 is sent once every 20ms• Unique in the network: constructed from MCC, MNC en E-UTRAN Cell Identifier


PCI PlanningRecommendations

In priority order, number 1 most important (all four should be fulfilled, ideally)

1. Avoid assigning the same PCI to neighbour cells

2. Avoid assigning the same mod3 (PCI) to ‘neighbour’ cells

3. Avoid assigning the same mod6(PCI) to ‘neighbour’ cells

4. Avoid assigning the same mod30 (PCI) to ‘neighbour’ cells

Id = 5

Id = 4

Id = 3

Id = 11

Id = 10

Id = 9

Id = 8

Id = 7

Id = 6

Id = 2

Id = 1

Id = 0

Example 1 PCI Identity Plan

Example 2 PCI Identity Plan


UL Reference SignalOverview

Types of UL Reference Signals• Demodulation Reference Signals (DM RS)

– PUSCH/PUCCH data estimation• Sounding Reference Signals (SRS)

– Mainly UL channel estimation UL (not in RL30)

DM RS is characterised by:• Sequence (Zadoff Chu codes)• Sequence length: equal to the # of subcarriers used for

PUSCH transmission (multiple of 12)• Sequence group:

▪ 30 options▪ Cell specific parameter

• Cyclic Shift: UE and cell specific parameter

UL DM RS allocation per slot for Normal Cyclic Prefix


UL DM Reference SignalNeed for Planning

Issue: • DM RS occupy always the same slot in time domain• In frequency domain DM RS of a given UE occupies the

same PRBs as its PUSCH/PUCCH data transmission• Possible inter cell interference for RS due to

simultaneous UL allocations on neighbour cells– No intra cell interference because users are

separated in frequency– Possible inter cell interference

Scope of planning: • DM RS in co-sited cells needs to be different

UL DM RS allocation per slot for Normal Cyclic Prefix


• RS sequences for PUSCH have different lengths depending the UL bandwidth allocated for a UE

• 30 possible sequences for each PRB allocation length of 1-100 PRBs• Sequences are grouped into 30 groups so they can be assigned to cells (different

sequence group to different cells)• Sequence group number ‘u’:

RS Sequences and RS Sequence Groups Sequence Group Id, ‘u’

30modSCHgrpAssigPU PCIu

grpAssigPUSCHdefines the assigned PUSCH group

LNCEL; 0..29; 1; 0


Cyclic Shift

• Additional sequences can be derived from a basic sequence by applying a cyclic shift• The reference signals derived from different cyclic shift of the same basic reference signal are

orthogonal• The basic reference signal length is 12 therefore up to 12 cyclic shifts can be derived • However in practice not 12 but maximum 8 cyclic shifts of a basic sequence are derived given

by the parameter ulRsCs = 0..7– The main reason to use only 8 cyclic shifts is to preserve the orthogonality between the reference signals

• Cyclic Shifts of a basic reference sequence are used to multiplex RS from different UEs within a cell

• Note that Cyclic shifts of an extended ZC sequence are not fully orthogonal, but have low cross-correlation– An extended sequence is a sequence with the length multiple of 12, e.g. 36, 72, …

ulRsCsDefines cyclic shift of UL RS

LNCEL; 0..7; 1; 0


UL DM Reference SignalHopping Techniques

• Reason for Hoping: Simultaneous UL allocation on neighbouring cells can have different bandwidth -> prevent RS cross-correlation between cells

• Sequence Hopping – Intra-Subframe hopping between two sequences within a sequence group for allocations larger

than 5PRBs– Only enabled is Sequence Group hopping in disabled– Not enabled in RL30: ulSeqHop= false

• Sequence Group Hopping– In each slot, the UL RS sequences to use within a cell are taken from one specific group– If group varies between slots: Group hopping– Group Hopping not enabled in RL30: UlGrpHop = false

▪ Group is the same for all slots

• Cyclic Shift Hopping– Always used– Cell specific cyclic shift added on top of UE specific cyclic shift


PlanningFrom Theory to Practice… (1/2)

Theory: • It should be possible to assign to the cells of one site the same sequence group ‘u’ and

‘differentiate’ the sequences using different cell specific cyclic shifts i.e. allocating different ulRsCs

Remember!: Cyclic shifts of an extended ZC sequence are not fully orthogonal, but have low cross-correlation


PlanningFrom Theory to Practice… (2/2)

Practice: • It doesn’t seem to work• UL Throughput gets considerably affected if UL traffic in neighbour cell

– From 40 Mbps to ~ 22 Mbps in the example

PCI grpAssigPusch sequence id u ulRsCs cinit75 0 15 0 7976 29 15 4 79


PlanningNew rule

• Allocate different sequence group u for every cell, including cells of the same site– Cross-correlation properties between sequences from two different groups are good because of sequence

grouping in the 3GPP spec• ulRsCs does not matter (it is only relevant for sequences within one seq group u)


Planning Results

• UL Throughput still suffers from UL interference in neighbour cell but the effect is lower

PCI grpAssigPusch sequence id u ulRsCs cinit75 0 15 0 7976 0 16 0 80


Pros an cons of the new planning rule

• [+]: Results seem to be better• [+]: Less parameters to plan, only PCI planning needed

– UlRsCs only relevant when using sequences of the same group– ‘u’ will be different if PCI module 3 rule is followed. In that case ‘grpAssigPUSCH’ value is not

relevant

• [ -]: Reduced group reuse distance compared to the case of assigning the same group per each site



UL DM RS PlanningWrap up

– If cells of the site follow the PCImod3 rule, the sequence group number ‘u’ will be different

– If PCImod3 rule is not followed, check PCImod30 rule ▪ If problems use grpAssigPUSCH to differentiate the ‘u’ - sequence group number-

– If same ‘u’ has to be used in neighbouring cells and cannot be changed using grpAssigPUSCH then assign different ulRsCs to the cells of a site. Range [0…7]

• Principle: DM RS needs to be different in cells from a same eNodeB

• Current planning approach:– Assign different sequence group number ‘u’ to the cells of the same site. Range: [0…

29]. grpAssigPUSCH can be constant =no need for planning



PDCCH Dimensioning

Scope: Optimize the resources reserved for PDCCH as they represent an overhead via maxNbrOfdmSymblPDCCH as RL10 & RL 20 does not support the dynamic variation of symbols per subframe

Note that in RL30 with the feature LTE616: Usage based PDCCH adaptation the number of OFDM symbols for PDCCH is dynamically adapted

• PDCCH resources are accounted in terms of CCEs that can also be aggregated in groups of 1, 2, 4 or 8 CCE. – 1 CCE = 9 Quadruplets = 36 RE– The higher the aggregation the more robust PDCCH (e.g. good at cell edge)

• Max. number of CCE for PDCCH depends on the bandwidth and the parameter maxNbrOfdmSymblPDCCH

• As PDCCH carriers the DCI not all the CCE are available for allocating user plane resources– Some of those CCEs broadcast DCI for system information and paging

Maximum number of CCE for different BW


PDCCH DimensioningmaxNrSymPdcch

• maxNbrOfdmSymblPDCCH defines how many symbols per subframe (1ms) are dedicated to carry PDCCH resources

• Considerations when planning the parameter value:– Max. number of simultaneous UL and DL grants to be scheduled per TTI– Desired aggregation level for users at cell edge:

▪ if not enough PDCCH capacity available scheduling will be blocked– Additional DL overhead introduced by increasing the number of PDCCH symbols and its impact

on the max achievable user throughputs

• Recommendation: maxNbrOfdmSymblPDCCH = 2 required to support 10UEs per TTI in RL10 & RL 20

– Information coming from Integration &Verification (I&V) for 20MHz BW.– It could be possible than in 10MHz value 3 is needed

• In RL30 maxNbrOfdmSymblPDCCH = 3 since the actual size will be dynamically aadapted

maxNrSymPdcchLNCEL; 1..3; 1; 3


PUCCH Dimensioning

Scope: Dimensioning of the PUCCH region (how many RBs) to avoid excessive overheads• PUCCH is used to transfer Uplink Control Information (UCI) when the PUSCH is not in use through

different PUCCH formats:

• PUCCH is allocated RBs at the 2 edges of the channel BW– To avoid fragmenting PUSCH RBs– To provide frequency diversity

• PUCCH always occupies 2 RBs distributed across the two time slots of a subframe• Each PUSCH transmission uses 1 RB on each side of the channel bandwidth

Note: RB in here corresponds to 3GPP definition of 12 subcarriers x 1 slot


n1PucchAnOffset to calculate ACK/NACK resources from PDCCH CCE

LNCEL; 0..2047; 1; 36

PUCCH Structure

• The logical split between the PUCCH formats is the following:• 1. Resources allocated for format 2/2a/2b i.e. CQI

– Number of resource blocks (RBs) defined by the parameter nCqiRb– The Parameter is semistatic allocated (and broadcasted)– Depends on the number of RRC connected UEs – Allocated on the outermost RBs (edge of the UL bandwidth)

• 2. Resources allocated for format 1/1a/1b – Semistatic allocation for Scheduling Request Information (SRI)– For SRI the parameter n1pucchAn is used to calculate the number of RBs (the parameteris broadcasted)– It depends on the number of RRC connected UEs– Dynamic allocation for ACK/NACK – The number of RBs for ACK/NACK depends on the total number of scheduled UEs

• 3. Mixed formats 1 & 2– Used for small bandwidth (e.g. 1.4 MHz)– pucchNanCS parameter used to calculated the number of RBs for mixed formats

pucchnanCSNumber of cyclic shifts for PUCCH formats 1/1a/1b in the mixed region

LNCEL; 0..7; 1; 0

(0 means no use of mixed formats )

nCqiRbreserved RBs per slot for PUCCH formats 2/2a/2b

LNCEL; 1..98; 1; 2


PUCCH UEs Multiplexing in One Resource Block

• For formats 2/2a/2b UEs are separated using CDM (code division multiplexing) inside the RB– CDM is using the cylcic shift of the length 12 CAZAC sequence– The numeber of cyclic shifts is given by the parameter deltaPucchShift – deltaPucchShift = 1,2,3 indicating 12, 6 or 4 shifts – With 12 shifts 12 UEs could be multiplexed in one RB, with 6 shifts 6 UEs could be multiplexed and so on – It is recommended that no more than 6 UEs are multiplexed per RB (even if 12 are possibile) to minimize interference

• For formats 1/1a/1b on top of CDM also a block wise spreading with an orthogonal cover sequence is applied – 3 orthogonal codes are used so the multiplexing capacity is 3 times increased – If 6 cyclic shifts and 3 orthogonal codes are used then the multiplexing capacity is 6*3= 18 UEs per RB

PUCCH formats Control typePUCCH Format 1 Scheduling requestPUCCH Format 1a 1-bit ACK/NACKPUCCH Format 1b 2-bit ACK/NACKPUCCH Format 2 CQIPUCCH Format 2a CQI + 1-bit ACK/NACKPUCCH Format 2b CQI + 2-bit ACK/NACK

Number of Bits Multiplexing Capacity (UE/RB)ON/OFF keying 36, *18, 12

1 36, *18, 12 2 36, *18, 12

20 12, *6, 42122

12,* 6, 412, *6, 4

*typical value deltaPucchShiftdelta cyclic shift for PUCCH formats 1/1a/1b

LNCEL; 1..3; 1; 2 (i.e. 6 cyclic shifts)


Number of Resource Blocks for formats 2/2a/2b

• The number of RBs required for formats 2/2a/2bdepends on the number of RRC connected UEsDefined by maxNumRrc parameterExample configuration 2:

• CQI periodicity is 20 ms -> there are 20 TTIs transporting CQIs • Assuming 6 UEs multiplexed per TTI and per RB then there are 6*20= 120 UEs (per 20 TTIs/ per RB)• So to support 840 RRC connected UEs we need: 840/120 = 7 RBs

• Please note that only 6 cyclic shifts are used in order to avoid interference (even if 12 cyclic shifts possible)

• With 12 cyclic shifts 12 UEs are multiplexed per TTIso the capacity is doubled (the number are in the brackets in the table)

Config

Number of RRC connected UEsmaxNumRrc

Number of RBsnCqiRb

CQI PeriodicitycqiPerNp

1. 840 (1680) 14 10 ms

2. 840 (1680) 7 20 ms

3. 768 (1536) 4 32 ms

4. 420 (840) 7 10 ms

5. 480 (960) 4 20 ms

6. 384 (768) 2 32 ms

7. 240 (480) 2 20 ms

8. 120 (240) 2 10 ms

9. 192 (384) 1 32 ms

10. 120 (240) 1 20 ms

11. 60 (120) 1 10 ms

Number of RBs allocated for

formats 2/2a/2b example

maxNumRrcMax. number of Ues in the cell with established RRC connection

LNCEL; 0..840; 1; 240 (*420 for 20 MHz bandwidth)cqiPerNpCQI periodicity

LNCEL; 2; 5; 10; 20; 20 ms


Number of Resource Blocks for formats 1/1a/1b – SRI

• The number of RBs for SRI depends on: • parameter n1PucchAn (Ack/Nack offset relative to the Lowest CCE index of the associated DL scheduling PDCCH)• Number of cyclic shifts deltaPucchShift

Example: Assuming that deltaPucchShift = 2 and the periodicity of SRI is 20 ms (cellSrPeriod parameter) then18 UEs could be multiplexed per TTI and per RB So there are 20*18 = 360 UEs per 20 msAssuming that maximum number of RRC connections maxNumRrc is 840 then we need roundup(840/360) = 3 RBsfor SRISo the offset for Ack/Nack -> n1PucchAn = 54

deltaPucchShift n1PucchAn Number of RBs for SRI

1 36 1

1 72 2

1 108 3

1 144 4

… … …

1 360 10

2 18 1

2 36 2

2 54 3

2 72 4

… … …

2 180 10

3 12 1

… … …

3 120 10

)12*3

*1(___

ShiftdeltaPucchPucchAnnroundupSRIRBsPUCCHNumber

cellSrPeriodSRI repetition period

LNCEL; 5ms(0), 10ms(1), 20ms(2), 40ms(3), 80ms(4); 20ms(2)


Number of Resource Blocks for formats 1/1a/1b – dynamic ACK/NACK

• The number of resource blocks for dynamic ACK/NACK is not fixed but it depends on the amount of scheduled UEs

• For the dimensioning of PUCCH resources for ACK/NACK the total number of CCE (control channel elements) available for PDCCH are considered :

• The total number of CCEs depends on the system bandwidth:

• Example: Assume that bandwidth is 10Mhz and the deltaPucchShift is 2 then the number

of resource blocks for dynamic ACK/NACK is:

)12*3

*(/___

ShiftdeltaPucchETotalNumCCroundupNACKACKRBsPUCCHNumber

Bandwidth Total Number of CCEs

5 MHz 21

10 MHz 43

15 MHz 65

20 MHz 87

3)12*3

2*43(/___ roundupNACKACKRBsPUCCHNumber


Number of RBs for PUCCH – total

• The total number of RBs required for PUCCH is the sum of RBs required for CQI, for SRI and dynamic ACK/NACK:

• If mixed formats 1/1a/1b and 2/2a/2b are supported for small bandwith then the total number of RBs for PUCCH is:

12*3

*1__

ShiftdeltaPucchPucchAnnETotalNumCCroundupnCqiRbRBsPUCCHNumber

812*3

*3*

1

__pucchNAnCs

roundup

ShiftdeltaPucchShiftdeltaPucch

pucchNAnCsPucchAnnETotalNumCC

roundupnCqiRbRBsPUCCHNumber


Exercise

• Assumptions:• Mixed formats 1/1a/1b and 2/2a/2b not used• Channel Bandwidth = 10 MHz • Maximum Number of RRC connections is MaxNumRrc = 240• The number of cyclic shifts is given by deltaPucchShift = 2 (6 cyclic shifts)• CQI periodicity given by CqiPerNp = 20 ms • SRI periodicity given by cellSrPeriod = 20 ms

• Task:• Plann the number of required RBs for PUCCH


Solution

• Step 1: identify the number of RBs required for formats 2/2a/2b (CQI)• CQI periodicity is 20 ms -> there are 20 TTIs transporting CQIs • The cyclic shift is 6 so there are 6 UEs multiplexed per TTI and per RB• 6 UEs multiplexed per TTI and per RB then there are 6*20= 120 UEs (per 20 TTIs/ per RB)• So to support 240 RRC connected UEs we need: 240/120 = 2 RBs• Step 2: identify the number of RBs required for formats 1/1a/1b for SRI• deltaPucchShift = 2 and because another 3 orthogonal codes are used -> 6*3= 18 UEs could be

multiplexed per RB and per TTI • SRI periodicity is cellSrPeriod = 20 ms so in 20ms there are 20*18 = 360 UEs per 20 ms • The number of RRC connected UEs is 240 < 360 so 1 RB is enough for SRI • Note that n1PucchAn = 18• Step 3: identify the number of RBs required for formats 1/1a/1b for dynamic ACK/NACK • Channel Bandwidth is 10 MHz so the total number of CCEs is 43• Number of required RBs = roundup((43*2)/(3*12)) = 3 RBs • Total number of RBs is the sum of the above = 2RBs + 1 RB + 3 RBs = 6 RBs

12 initial parameter planning gc

Documents

mixed formats 1 1a 1b

sequence group number

formats 1 1a 1b

multiplexing capacity

formats 2 2a 2b

sequence group

rl10

3 orthogonal codes