LTE PHY Overview
Gwanmo Ku Adaptive Signal Processing and Information Theory Research Group Nov. 4, 2011
Outline 2/25
LTE Introduction LTE PHY PHY Standard Descriptions Protocol Architecture Standard Docs. Parameters Frame Structures PHY Resources Modulation, Channel Coding, and Physical Channels
References
2/11
LTE Introduction
Why LTE? 4/25
Continuity of Competitiveness of 3G System
Higher Data Rate QoS
Packet Switch Optimized System
LTE High Spectral Efficiency Very Low Latency Support of Variable Bandwidth
(Reference: http://www.3gpp.org/LTE)
LTE Multiple Access 5/25
Base Station (eNB) DL : OFDMA with CP
UL : DFTS-OFDMA with CP Mobile (UE)
DL (Downlink), UL (Uplink), CP (Cyclic Prefix) eNB (e Node B), UE (User Equipment) DFTS-OFDMA (DFT Spread OFDMA) : also called as SC-FDMA (Single Carrier FDMA) (Reference : p7, 3GPP TS 36.201 V8.3.0 (2009-03))
OFDMA & SC-FDMA 7/25
OFDMA
Bits
Constellation Mapping & S/P
- DFT
Subcarrier Mapping
- IFFT
Add CP & P/S
DFT Spread
+
SC-FDMA (DFT Spread OFDMA)
S/P (Serial to Parallel Conversion), P/S (Parallel to Serial Conversion) : Used Subcarriers : Total Subcarriers
(Reference : p. 71, 3GPP TR 25.814 V7.1.0 (2006-09))
2/11
LTE PHY Standard Descriptions
LTE Protocol Architecture 9/25
LTE Protocol Architecture around PHY Layer 3
Radio Resource Control (RRC)
Logical Channels Layer 2
Medium Access Control (MAC)
Control / Measurements
Transport Channels Layer 1
Physical Layer (PHY)
Logical Channels : Type of information transferred Transport Channels : How the information is transferred (Reference : p. 7, 3GPP TS 36.201 V8.3.0 (2009-03))
LTE PHY Standard Docs. 10/25
Rel-8 36 Series : LTE Requirements
Rel-9 36 Series : LTE with Enhancement Rel-10, 11, … 36 Series : LTE Advanced Rel-8 362XX : LTE PHY Technical Spec. 36201 : LTE PHY General Descriptions
Layer 1
36211 : Physical channels and modulation 36.212 : Multiplexing and channel coding 36.213 : Physical layer procedures
Layer 2 & 3
36.214 : Physical layer Measurements
PHY Parameters 11/25
DL/UL Parameters System BW [MHz]
1.4
3
5
10
15
20
# Resource Blocks
6
15
25
50
75
100
2048
∆ =
FFT Size -
∆ = .
4096* 12
∆ =
# Subcarriers per RB -
∆ = . ∆ =
72
180
300
24* 600
900
1200
# Used Subcarriers -
∆ = .
Sampling Rate [MHz]
1.92
3.84
7.68
2400* 15.36
23.04
30.72
Subcarrier Spacing ∆ = 15 UL/DL, ∆ ∗ = 7.5 DL only
(Reference : 3GPP TS 36.101 V8.15.0 (2011-09))
PHY Parameters – CP Length
12/25
One Slot 0.5 ms (500 s)
DL/UL Normal CP 5.2083 0
4.6875 Symbol 0
1
Symbol 1
2
Symbol 2
3
Symbol 3
4
Symbol 4
5
Symbol 5
6
Symbol 6
CP5
Symbol 5
66.6667
DL/UL Extended CP with Freq. Spacing 15 KHz 66.6667 cp0
Symbol 0
CP1
Symbol 1
CP2
Symbol 2
CP3
Symbol 3
CP4
Symbol 4
16.6666
DL Extended CP with Freq. Spacing 7.5 KHz 133.33 cp0
Symbol 0
CP1
Symbol 1
CP2
Symbol 2
33.333
(Reference : 3GPP TS 36.211 V8.9.0 (2009-12))
Operating Bands (700 MHz) 13/25 FDD Uplink
FDD Downlink
TDD LTE Recommendation
700 MHz
699
716
Band 12
704
729
746
Band 12
800
750
756
758
Band 13
768
Band 14
777
787
Band 13
788
798
Band 14
716
Band 17
Band 17
757
C
776
C
Verizon LTE Plan in US FCC Upper 700 MHz Band C FCC Band in US
References : [1] 3GPP TS 36.101 V8.15.0 (2011-09) [2] FCC Doc. : http://transition.fcc.gov/Daily_Releases/Daily_Business/2011/db0630/FCC-11-103A1.pdf
Operating Bands (800 MHz) 14/25 FDD Uplink
FDD Downlink
TDD LTE Recommendation
800 MHz
850 824
849
869
Band 5
830
900
750
950
894
960
Band 5
840
875
Band 6
885
Band 6
880
915
Band 8
Cellular
925
Band 8
Cellular FCC Cellular Band But unavailable for LTE
References : [1] 3GPP TS 36.101 V8.15.0 (2011-09) [2] FCC Doc. : http://transition.fcc.gov/Daily_Releases/Daily_Business/2011/db0630/FCC-11-103A1.pdf
Operating Bands (1700-2200 MHz) 15/25 FDD Uplink
FDD Downlink
TDD LTE Recommendation
1700 MHz
1800
1710
1785
Band 3
1900
1805
2000
1880
Band 3
1770
1920
Band 39
1850
Band 10
1910
Band 35
1980
Band 1 1930
Band 37
2010 Band 34
2100 2025
2200
2110
2170
Band 1
1990
Band 36
1755
Band 10
2155
Band 4
Band 2
1749.9
1784.9
Band 9
1844.9
Band 2
Band 4
1879.9
Band 9
Band33
FCC PCS Broadband and Advanced Wireless Services (AWS) AWS1
PCS Broadband
PCS Broadband
AWS1
AT&T LTE Plan : AWS band References : [1] 3GPP TS 36.101 V8.15.0 (2011-09) [2] FCC Doc. : http://transition.fcc.gov/Daily_Releases/Daily_Business/2011/db0630/FCC-11-103A1.pdf
Operating Bands (1400 & 2300-2700 MHz) 16/25 FDD Uplink
1400 MHz
1500
FDD Downlink
TDD
2300
2400
2500
LTE Recommendation 2600 2700
1427.9 1447.9 1475.9 1495.9
Band11
2570
Band11
Band 40
Band 7
2620
Band38
2690
Band 7
FCC Broadband Radio Service (BRS) and Educational Broadband Service (EBS) BRS EBS BRS + EBS
2502
2602
2673.5
2690
But LTE available BW upto 5MHz
References : [1] 3GPP TS 36.101 V8.15.0 (2011-09) [2] FCC Doc. : http://transition.fcc.gov/Daily_Releases/Daily_Business/2011/db0630/FCC-11-103A1.pdf
Frame Structure 17/25
Frame Structure Type 1 : FDD
Frame Structure Type 2 : TDD
5ms Switch
10ms Switch
(Reference : 3GPP TS 36.211 V8.9.0 (2009-12))
Frame Structure – TDD (Cont.)
18/25
UL/DL Configurations Sub-frame Number
UL-DL Configuration
DL to UL Switch Point Periodicity
0
1
2
3
4
5
6
7
8
9
0
5 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
Subframe Index : D (Downlink), U (Uplink), S (Special) (Reference : 3GPP TS 36.211 V8.9.0 (2009-12))
PHY Resources 19/25
Resources in LTE
Resources : # Usable Subcarriers
Resource Block & Slot Frequency
0.5 ms
Resourcce Block BW
180 kHz
time
(Reference : 3GPP TS 36.211 V8.9.0 (2009-12))
PHY Resources – UL Slot Structure
20/25
Frequency Nullities …
SC-FDMA Symbols
∙
BW [MHz]
1.4
3
5
10
15
20
6
15
25
50
75
100
128
256
512
1024
1536
2048
Configuration
Normal CP
12
7
Extended CP
12
6
Configuration
CP Length 160 for 0th Symbol
Normal CP 144 for 1~6th Symbol …
Extended CP
512 for 0~5th Symbol
Nullities
time 1 Slot
(Reference : 3GPP TS 36.211 V8.9.0 (2009-12))
PHY Resources – DL Slot Structure
21/25
Frequency Nullities …
OFDMA Symbols
BW [MHz]
1.4
3
5
10
15
20
6
15
25
50
75
100
128
256
512
1024
1536
2048
∆ = 15
12
7
∆ = 15
12
6
∆ = 7.5
24
3
Configuration Normal CP
∙
Extended CP
Configuration
CP Length 160 for 0th Symbol
Normal CP
∆ = 15
144 for 1~6th Symbol …
∆ = 15
512 for 0~5th Symbol
∆ = 7.5
1024 for 0-2 nd Symbol
Extended CP
Nullities
time 1 Slot
(Reference : 3GPP TS 36.211 V8.9.0 (2009-12))
Modulations, Coding, Physical Channels 22/25
Modulations
Channel Coding
QPSK, 16QAM, 64QAM
Turbo Coding
Physical Channels
DL Physical Channels PDSCH, PDCCH, PCFICH, PBCH, PMCH, PHICH
UL Physical Channels PUSCH, PUCCH, PRACH (Reference : 3GPP TS 36.212 V8.8.0 (2009-12))
Future Work (Next Talk) 23/25
LTE
Resource Allocation
AMC (Adaptive Modulation and Coding)
2/11
References
References 25/25 •
•
LTE related Webpages
http://www.3gpp.org
: 3GPP Standard Web
http://www.fcc.gov/
: FCC
http://wireless.fcc.gov/uls/
: FCC Band License Search
LTE Standard Docs. – Release 8 Technical Specs.
•
FCC Useful Doc. – 15th Report
•
http://www.3gpp.org/ftp/Specs/latest/Rel-8/36_series/
http://transition.fcc.gov/Daily_Releases/Daily_Business/2011/db0630/FCC-11-103A1.pdf
DFTS-OFDMA (SC-FDMA)
http://sites.google.com/site/hgmyung/scfdma
