Reference Signal for LTE-Advanced

1. Reference Signal
for LTE-Advanced
Arumjeni Mitayani

2. Prologue

3. Reference Signal
• Downlink
– Cell-specific reference signals
– MBSFN reference signals
– UE-specific reference signal (evo)
– Positioning reference signal
– CSI reference signal (evo)
• Uplink
– Generation of the reference signal sequence
– Demodulation reference signal (evo)
– Sounding reference signal (evo)

4. Cell-specific RS
• Rel. 8
– Non-MBSFN transmission
• Rel. 9
– PDSCH transmission
• Rel.10
– PDSCH transmission

5. Cell-specific RS (2)
0l
0R
0R
0R
0R
6l 0l
0R
0R
0R
0R
6l
OneantennaportTwoantennaports
Resource element (k,l)
Not used for transmission on this antenna port
Reference symbols on this antenna port
0l
0R
0R
0R
0R
6l 0l
0R
0R
0R
0R
6l 0l
1R
1R
1R
1R
6l 0l
1R
1R
1R
1R
6l
0l
0R
0R
0R
0R
6l 0l
0R
0R
0R
0R
6l 0l
1R
1R
1R
1R
6l 0l
1R
1R
1R
1R
6l
Fourantennaports
0l 6l 0l
2R
6l 0l 6l 0l 6l
2R
2R
2R
3R
3R
3R
3R
even-numbered slots odd-numbered slots
Antenna port 0
even-numbered slots odd-numbered slots
Antenna port 1
even-numbered slots odd-numbered slots
Antenna port 2
even-numbered slots odd-numbered slots
Antenna port 3

6. Cell-specific RS (3)
• Generation
12,...,1,0,)12(21
2
1
)2(21
2
1
)( DLmax,
RB, s
Nmmcjmcmr nl
CP
cell
ID
cell
IDs
10
init 2121172 NNNlnc
Input:
- N max DL RB
- N cell ID
- N CP
- n s
Output:
- CRS (3 dimension)

7. Cell-specific RS (4)
• Mapping
)'(s,
)(
, mra nl
p
lk
DL
RB
DLmax,
RB
DL
RB
DL
symb
shift
12,...,1,0
3,2if1
1,0if3,0
6mod6
NNmm
Nm
p
pN
l
vvmk
Input:
- N max DL RB
- N DL RB
- N cell ID
- n s
- CRS
3if)2mod(33
2if)2mod(3
0and1if0
0and1if3
0and0if3
0and0if0
s
s
pn
pn
lp
lp
lp
lp
v
6modcell
IDshift Nv
Output:
- Slot (3 dimension)

8. MBSFN-RS
• Only supported in extended cyclic prefix mode
0l 5l 0l 5l
even-numbered slots odd-numbered slots
Antenna port 4
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
4R
Using antenna
port 4

9. MBSFN-RS (2)
• Generation
16,...,1,0,)12(21
2
1
)2(21
2
1
)( DLmax,
RB, s
Nmmcjmcmr nl
MBSFN
ID
MBSFN
ID
9
init 121172 NNlnc s
Input:
- N max DL RB
- N MBSFN ID
- n s
Output:
- MBSFNRS (3 dimension)

10. MBSFN-RS (3)
• Mapping
)(s,
)(
, mra nl
p
lk
DL
RB
DLmax,
RB
DL
RB
s
s
s
s
3
16,...,1,0
kHz5.7and12modif2,0
kHz5.7and02modif1
kHz15and12modif4,0
kHz15and02modif2
kHz5.7and0if24
kHz5.7and0if4
kHz15and0if12
kHz15and0if2
NNmm
Nm
fn
fn
fn
fn
l
flm
flm
flm
flm
k
Input:
- n s
- N max DL RB
- N DL RB
- MBSFNRS
Output:
- Slot (3 dimension)

11. UE-specific RS
• Purpose
– Enable channel estimation for demodulation
– Allows reduced RS overhead
– Obtain more accurate interference estimates in
partial loading scenarios
• 1
• 2
• 3

12. UE-specific RS (2)
0l
even-numbered slots odd-numbered slots
Antenna port 5
5R
5R
5R
5R
5R
5R
5R
5R
5R
5R
5R
5R
0l 6l6l

13. UE-specific RS (3)
0l 6l 0l 6l
Specialsubframe,configuration1,2,6or7Specialsubframe,configuration3,4or8
0l 6l 0l 6l 0l 6l 0l 6l
0l 6l 0l 6l 0l 6l 0l 6l
Allotherdownlinksubframes
0l 6l 0l 6l 0l 6l 0l 6l
even-numbered slots odd-numbered slots
Antenna port 7
even-numbered slots odd-numbered slots
Antenna port 8
even-numbered slots odd-numbered slots
Antenna port 9
even-numbered slots odd-numbered slots
Antenna port 10
7R 7R 7R 7R
7R7R7R7R
7R 7R 7R 7R 8R 8R 8R 8R
8R 8R 8R 8R
8R 8R 8R 8R
9R 9R 9R 9R
9R 9R 9R 9R
9R 9R 9R 9R
10R 10R 10R 10R
10R 10R 10R 10R
10R 10R 10R 10R
7R 7R
7R7R
7R 7R
7R 7R
7R7R
7R 7R 8R 8R
8R 8R
8R 8R
8R 8R
8R 8R
8R 8R
7R 7R
7R7R
7R 7R
7R 7R
7R7R
7R 7R 8R 8R
8R 8R
8R 8R
0l 6l 0l 6l
8R 8R
8R 8R
8R 8R
0l 6l 0l 6l 0l 6l 0l 6l
0l 6l 0l 6l 0l 6l 0l 6l
9R 9R
9R 9R
9R 9R
9R 9R
9R 9R
9R 9R
10R 10R
10R 10R
10R 10R
10R 10R
10R 10R
10R 10R
9R 9R
9R 9R
9R 9R
9R 9R
9R 9R
9R 9R
10R 10R
10R 10R
10R 10R
10R 10R
10R 10R
10R 10R

14. UE-specific RS (4)
• Generation
11210,)12(21
2
1
)2(21
2
1
)( PDSCH
RBs
N,...,,mmcjmcmrn
RNTI
16cell
IDsinit 21212 nNnc
prefixcyclicextended11610
prefixcyclicnormal11210
,)12(21
2
1
)2(21
2
1
)( DLmax,
RB
DLmax,
RB
N,...,,
N,...,,
mmcjmcmr
SCID
16cell
IDsinit 21212/ nNnc
Input:
- N PDSCH RB
- N cell ID
- n RNTI
- N max DL RB
- n SCID
Output:
- DMRS for port 5
(2 dimension)
- DMRS for others
(3 dimension)

15. UE-specific RS (5)
• Mapping
)'3( PDSCH
RB
)(
, s
mNlra n
p
lk
13,...,1,0'
12modif2,3
02modif1,0
35
22
16
03
6,5if4mod)2(4m'
3,2if'4
mod)(
PDSCH
RB
s
s
shift
shift
PRB
RB
sc
RB
sc
Nm
n
n
l
l
l
l
l
l
lv
lvm
k
nNNkk
Input:
- N PDSCH RB
- n s
- N sc RB
- n PRB
- DMRS
Output:
- Slot (3 dimension)
3modcell
IDshift Nv

16. UE-specific RS (6)

17. Positioning RS
0l 6l 0l 6l
FourPBCHantennaports
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
0l 6l 0l 6l
OneandtwoPBCHantenna
ports
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
6R
even- numbered slots odd- numbered slots
Antenna port 6
even-numbered slots odd- numbered slots
Antenna port 6

18. Positioning RS (2)
• Generation
12,...,1,0,)12(21
2
1
)2(21
2
1
)( DLmax,
RB, s
Nmmcjmcmr nl
CP
cell
ID
cell
IDs
10
init 2121172 NNNlnc
Input:
- N max DL RB
- n s
- N cell ID
- N CP
Output
- PRS (3 dimension)

19. Positioning RS (2)
• Mapping
)'(s,
)(
, mra nl
p
lk
PRS
RB
DLmax,
RB
PRS
RB
s
s
s
shift
PRS
RB
DL
RB
12,,1,0
portsantennaPBCH4and12modif6,5,3,2
portsantennaPBCH2or1and12modif6,5,3,2,1
02modif6,5,3
6mod66
NNmm
Nm
n
n
n
l
vlNNmk

6modcell
IDshift Nv
Input:
- N DL RB
- N PRS RB
- N max DL RB
- N cell ID
- PRS
Output:
- Slot (3 dimension)

20. CSI-RS
• Purpose
– To support 8-layer spatial multiplexing
– Replace legacy data symbols on CSI-RS REs
– Better support of coordinated multipoint (CoMP)
• 1
• 2

21. CSI-RS (2)
even-numbered slots odd-numbered slots even-numbered slots odd-numbered slots even-numbered slots odd-numbered slots even-numbered slots odd-numbered slots
0l 6l 0l 6l 0l 6l 0l 6l 0l 6l 0l 6l 0l 6l 0l 6l
0l 6l 0l 6l 0l 6l 0l 6l 0l 6l 0l 6l 0l 6l 0l 6l
15R 15R 16R 16R
17R 17R 18R 18R
19R 19R 20R 20R
21R 21R 22R 22R

22. CSI-RS (3)
• Generation
1,...,1,0,)12(21
2
1
)2(21
2
1
)( DLmax,
RB, s
Nmmcjmcmr nl
CP
cell
ID
cell
IDs
10
init 2121172 NNNlnc
Input:
- N max DL RB
- N cell ID
- N CP
- n s
Output:
- CSIRS (3 dimension)

23. CSI-RS (4)
• Mapping )'(s,"
)(
, mrwa nll
p
lk
2
DL
RB
DLmax,
RB'
1
DL
RB,...,1,0
1,0"
22,20,18,16
"
1
21,19,17,151
prefixcyclicextended27,-0ionsconfiguratsignalreferenceCSI"
prefixcyclicnormal31,-20ionsconfiguratsignalreferenceCSI"2
prefixcyclicnormal19,-0ionsconfiguratsignalreferenceCSI"
'
prefixcyclicextended,22,21for9
prefixcyclicextended,20,19for6
prefixcyclicextended,18,17for3
prefixcyclicextended,16,15for0
prefixcyclicnormal,22,21for7
prefixcyclicnormal,20,19for1
prefixcyclicnormal,18,17for6
prefixcyclicnormal,16,15for0
12'
NN
mm
Nm
l
p
l
p
lw
l
l
l
ll
p
p
p
p
p
p
p
p
mkk
Input:
- N DL RB
- N max DL RB
- P
- CSI config
- N CP
- CSIRS
Output:
- Slot (3
dimension)

24. CSI-RS (5)

25. Demodulation RS
• To reduce downlink signaling overhead, 3 bit
field is used to signal combination of CS and
OCC

26. Evolution
• LTE Release 8
– SRS is based on the extended ZC sequence
• LTE Release 10
– Aperiodic SRS (A-SRS)
• 2

27. Sounding Reference Signal