lte scheduling

L13 Radio Network Functionality Ch 4

Power control scheduling ,Link adaption

Commercial in confidence | 2013-07-29 |

1. Introduction

2. QoS Handling

3. Scheduling

4. Serving specific DRX

5. Power control

6. Link adaptation

7. MIMO in LTE

8. Parameters

Agenda


introduction

訊息回報

訊息下載

上行功率控制


eNBessential function

Scheduling(DRA)

eNB Essential function

資料下載Transport format 所傳送的資料格式

控制訊息 : transmitter power control(closed loop)SIB2 power control(open loop)

downlink

訊息回報 :

Channel quality indicator目前的下行通道狀況為何Rank indicatorUE 建議使用的 MIMO 狀況Precoding Matrix indicatorUE 建議使用的編碼方式

UECFR

http://www.sharetechnote.com/html/PowerControl_LTE.html

Page 149


introduction

上報通道狀況

由 CQI 回算 RS 的 SINR 推算出 PDSCH 的 SINR



Scheduling(DRA)

訊息回報 :

Channel quality indicator目前的下行通道狀況為何

由 UE 回報的 CQI 來進行通道估測算出 RS 的 SINR, 再算出 GINR, 再算出 PDSCH 的SINR

SINR (PDSCH)

downlink

UE



SINR/GINR http://www.hindawi.com/journals/ijdsn/2010/509297/

K 個子載波的 Channel Gain 總和

Noise + 從其他 cell 來的”干擾”信號的強度

SINR=


CQI & Channel Prediction


CQI-MCS-TBS


One Radio Frame 10ms= 10 sub-frame (1ms X10)

1 sub-frame (1ms) = 2 slotSlot = 7 Symbols ( CP+ Useful symbol)

==10ms 有 7X2X10= 140 symbol

For 64QAM and 2X2 MIMO, 15M BW ( 1 ) X 6X2X140X100X900= 151Mbps

15M= 75 PRB= 900 RE

5M= 25 PRB= 300RE

Fre

que

ncy (Ba

ndw

idth)

Time =10ms (1 Radio Frame) = 140 symbol

通道狀況

c


DL throughputestimated

Table 7.1.7.1-1_PDSCH Table 7.1.7.2.1-1

3GPP TS36.213

Microsoft Excel 97-2003 Worksheet

Estimated=105 Mbps


introduction

訊息回報訊息上載

由 PHR 推估 PSD



Scheduling(DRA)

uplink

資料上載Transport format 所傳送的資料格式

控制訊息 : transmitter power control(closed loop) SIB2 power control(open loop)

訊息回報 :Power Head Room還有多少可調整空間Buffer Status ReportUE 告訴基站緩衝區的狀態Scheduling RequestUE 告訴基站的”排程需求” UE




Scheduling(DRA)

eNB Essential function uplink

訊息回報 :Power Head Room還有多少可調整空間

UE

SINR (PUSCH) PSD (RX),G

由 UE 回報的 PHR 來估計 PSD(TX)運用 UE 回報 PSD(RX) 與計算的 Gain 來評估UL Power Control


PSD power spectrum density


QoS Handling&Scheduler

QCI table

QoS Handling

Scheduler


QCI table/Qos configuration

non-GBR = none guaranteed bit rate

VoLTE

Now


QCI information & DSCPQCI Traffic Class

Traffic HandlingPriority

SignallingIndication

Source StatisticsDescriptor

QCI Profile Predefined ID

DSCP LGC

1 Conversational N/A N/A Speech qci1 46 1

2 Conversational N/A N/A Unknown qci2 36 1

3 Conversational N/A N/A Unknown qci3 34 1

4 Streaming N/A N/A Unknown qci4 38 1

5 Interactive 1 Yes N/A qci5 40 1

6 Interactive 1 No N/A qci6 26 1



9 Background N/A N/A N/A qci9 14 1

10-255 Not defended default 0 1

(THP)

2^5 (1)+2^3(1)+2^2(1)+2^1(1) =32+8+4+2=46

K-get data

Now


Mapping QCI to DSCP

BSR= buffer status report


QoS Aware Scheduler


NEMO-example


SchedulingRRM, power control, Link ada…ICIC

downlink


› Proportional Fair Scheduling has 5 Main Scheduling Flavors– Equal Rate– Proportional Fair High– Proportional Fair Medium– Proportional Fair Low– Max C/I

› Minimum Bit Rate Scheduling– Allows operator to configure different minimum bit rates for different bearer types– Consistent cell edge throughput

Market deployment considerations

TTITTI

PR

B

PR

B

Equal Rate schedulingMax C/I scheduling

Higher Fairness Higher Cell Capacity

TTI

PR

B

Resource Fair scheduling

Lower RF UE More PRB resources Higher RF UE

More PRB resources

P.F.H.

P.F.M.

P.F.L.

High RF User Medium RF User Low RF User


Scheduler Control


CQI sub-band

Band Width

Sub-band size (k)

6 – 7 N/A

8 – 10 4

11 – 26 4

27 – 63 6

64 - 110 8

Band Width

Number of sub-bands

6 N/A

15 4

25 7

50 9

75 10

100 13

75/8=9…39+1=1050/6=8…2 8+1=9

不同頻寬 (RB)的狀況下 CQI所代表的頻寬並不相同 ,上報的數量也不相同

頻寬 =75 RBs 時拆分成 10組來上報

頻寬 =50 RBs 時拆分成 9 組來上報


Example-CQI sub-band

L1800@BW=15MHz L900@BW=10MHz

0~9

0~8

L900@BW=5MHz

0~6


Band Width

RBG Size (P)

≤10 1

11 – 26 2

27 – 63 3

64 - 110 4

DL resource block allocation

Band Width

Number of RBG’s

6 6

15 8

25 13

50 17

75 19

100 254 RBs 1 RBG每 4 個 RB 組成一個 RBG

75/4=18…319每個 RBG 有 4 個 RB最後一個 RBG 僅有 3 個 RB


DOWNLINK PRBS (NEMO)

4 個 RB 組成 RBG


DOWNLINK PRBS (NEMO)

共 19 組 RBG


Scheduling

uplink


UPLINK PRBS (NEMO)

3 個 RB 組成 RBG


UPLINK PRBS (NEMO)

2 個 RB 所組成 RBG


For UE synchronization

for UE determiningthe serving cell coverage

Commercial in confidence | 2013-07-29 | 1 Radio Frame


1 slot 7 OFDMA symbol (Normal CP)

12

Su

b ca

rrie

r

1 Resource Block = 12 x 7 =84 Resource element

delta f=15KHz 15x12=180KHz(1 RB =180KHz)


BW=5 MHz FFT size=512對應到 PHY 層時，意義為產生 512 個正交的子載波 (subcarrier)然而實際用於傳輸的頻寬僅有 4.5MHz, 左右保留 0.25MHz 作為保護頻寬

Example of BW=5MHz delta f=15KHz1 RB 包含 12 個 delta f15x12=180KHz

15MHz 共有 75 個 RB 180x75=13.5MHz

15MHz 實際有用 1536 個子載波 15x1536=23.04MHz


Freq.

Power


Master information block (MIB)10ms

Repeated MIB New MIB

› Resource elements used by MIB are the first 4 OFDMA symbols of second slot of first sub-frame of a radio frame.

› On frequency domain it occupies 72 sub-carriers.

4 OFDMA Symbols

Slot 1

Slot 2

Period=40ms

PBCH(1/2)


@ sub-frame 0, slot 2, symbol 0~3

PBCH(MIB) QPSKMaster information block72x 15KHz= 1080KHz=1.08MHz72x 4=288 there are12 CRS RE288-12=276 REsoccupied 240 REs

PBCH(2/2)


› Synchronization signal : › On frequency domain it occupies 72 sub-carriers.

› Primary SS @ symbol 6, › Secondary SS @ symbol 5

72 R

es=

6 R

Bs

P-SS & S-SS


@ sub-frame 0& 5, slot 1, symbol 5 for SSS(0~167) BPSKSymbol 6 for PSS(0~2) Z-Chu72x 15KHz= 1080KHz=1.08MHzReserve 5 delta f for future use at each side72x4=288 occupied 288 REs

5 delta f

P-SS & S-SS


PCFICHphysical control Format indicator Channel

› Symbol 0~2 for each 1ms sub-frame.› More user long overhead low data rate› Less user short overhead high data rate

CFI=1 CFI=3

PCFICH occupies four REGs (16 REs),independent of system bandwidth. It is mapped on OFDM symbol 0 of the first slot in all downlink sub-frames


@ sub-frame 0~9, slot 1, symbol 0~2PCFICHQPSKRBs x12 x 15KHz= full bandCFI=1 (12 -2)*RBs or (12-4)*RBsCFI=2 <CFI=1> + 12*RBsCFI=3 <CFI=2> + 12*RBs


PHICHphysical Hybrid ARQ indicator Channel

PHICH is only mapped to sub-frames in downlink where HARQ signaling can be expected. Therefor is the number of downlink sub-frames that carry PHICHequal to the number of configured uplink sub-frames.

PHICH group =10 10 * 12 (REs)* 10 (sub-frame) =1200


@ sub-frame 0~9, slot 1, symbol 0~2PHICHBPSK


PCFICH & PHICHhttp://www.slideshare.net/deepakecrbs/ltetutorial-100126072043-phpapp01-1

12 bits


PCFICH & PHICH

Example:120120 + (50/2)*(12/2) = 270120 + 2*(50/2)*(12/2) = 420120 + 3*(50/2)*(12/2) = 570

PCI=0~503

Sub-carrier=12

RB=75 @15MHz

http://4g-lte-world.blogspot.tw/2013/09/physical-control-format-indicator.html

http://www.sharetechnote.com/html/Handbook_LTE_PHICH_PHICHGroup.html

#Num PHICH group @ Normal-CP

Example:[ 1* (75/8) ]=[9.375]=10[ 1/6* (75/8) ]=[1.625]=2


PDCCH

4 REs1 REGs, 9 REGs 1 CCE(36REs)


PDCCH CCE allocation


CRSCell specific Reference signals

8 RE for Reference signal @ Ant. port0

4 x 2 (slot 0~1) x 75(RBs) x10(sub-frame0~9)

4 RE hole

Shift 6 REs


› ftp://www.3gpp.org/workshop/2009-12-17_ITU-R_IMT-Adv_eval/docs/pdf/REV-090007%20SelfEvalulation%20assumption.pdf


ftp://www.3gpp.org/workshop/2009-12-17_ITU-R_IMT-Adv_eval/docs/pdf/REV-090007%20SelfEvalulation%20assumption.pdf

Ant. port0 Ant. port1



http://www.sharetechnote.com/html/FrameStructure_DL.html


RS power (5W)

6.7dBm+30dB=36.7dBm 36.7dBm≈5W.-0.3dBm+30dB=29.7dBm 29.7dBm≈1W.


PDCCh-CFI

CHT parameter

PDCCH is transmitted in the beginning of each downlink sub-frame in REsnot used for reference signals, PHICH or PCFICH. Mapping the PDCCHs toREs is based on CCEs, see Section 2.5 on page 6. The number of CCEsrequired for a certain PDCCH depends on the PDCCH message size and onthe channel coding rate. It is restricted to four different aggregation levels, 1,2, 4 or 8 CCEs per PDCCH.

1 CCE= 36 Res @ 1 sub-frame 360 REs @ 1 frame

CHT BW=15MHz75*12*2*10=18000

-CRS -PCFICH-PHICH

13320 ??

L1800


PUCCH› PUCCH is used for:

› Hybrid Automatic Repeat Request (HARQ) – ACK/NACK› Scheduling Request (SR)› Channel status reports, Channel Quality Indicator (CQI) and Rank Indicator (RI)

Freq.

Freq.

PUCCH


AILGAILG=50% AILG=75%

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