IEEE C80216m-09/0156r1
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Data mapping for SFBC
Date
Submitted
2009-1-5
Source(s)
Xiaolong ZHU, Dong LI, Hongwei Yang,
Keying WU
Voice: + 86-21-50554550;
Fax:+ 86-21-50554554
Mail to: [email protected]
Alcatel Shanghai Bell
Re:
IEEE 802.16m-08/052 Call for Comments on Project 802.16m System Description Document
(SDD): 11.8 & 11.12
Abstract
This contribution presents the data mapping for downlink and uplink space-frequency block
coding (SFBC), which aligns well with the one specified for space-time block coding (STBC) in
legacy IEEE802.16e systems.
Purpose
Adopt the proposed text into SDD.
Notice
Release
Patent
Policy
This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It
represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for
discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material
contained herein.
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution,
and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name
any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole
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contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.16.
The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and
<http://standards.ieee.org/guides/opman/sect6.html#6.3>.
Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and
<http://standards.ieee.org/board/pat>.
Data Mapping for SFBC
Xiaolong ZHU, Dong LI, Hongwei YANG, Keying WU
Alcatel Shanghai Bell
1 Introduction
In the current 16m SDD [1], space-frequency block coding (SFBC) is accepted as one of transmit diversity
schemes for both downlink and uplink. This contribution presents the detailed data mapping for SFBC. The
proposed data mapping aligns well with the one specified for space-time block coding (STBC) in legacy
802.16e systems as shown in Figure 1 (cf. Figure 274 in [2]). More specifically, the legacy STBC encoder (or
decoder) can be reused for 802.16m SFBC by only adjusting the mapping (or de-mapping) pattern.
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IEEE C80216m-09/0156r1
Figure 1 ---- Data mapping example for STBC in legacy 802.16e systems [2].
2 Data mapping for downlink SFBC
The downlink physical structure is defined in Section 11.5. The downlink open-loop single-user transmit
diversity schemes are defined in 11.8.2.1.1.1, as follows [1]:

2Tx rate-1: For M=2, SFBC, and for M=1, a rank-1 precoder

4Tx rate-1: For M=2, SFBC with precoder, and for M=1, a rank-1 precoder

8Tx rate-1: For M=2, SFBC with precoder, and for M=1, a rank-1 precoder
For the transmit diversity modes with M=2, the input to the MIMO encoder is x=[s1;s2], and the MIMO encoder
generates the following SFBC matrix
s
z 1
 s2
 s2* 

s1* 
where the row indicates the index of transmit antennas, the column indicates the index of subcarriers, and the
superscript “*” denotes complex conjugate.
The 2-stream pilot pattern A is shown in Figure 2 (cf. Figure 40 in [1]), and the pilot locations are expressed by
Pilot Location for Stream #0 = 18*k – 8*mod(m+2,3) + 16
Pilot Location for Stream #1 = 18*k – 8*mod(m+2,3) + 17
Where m = [symbol index], symbol index 0 is the first symbol in which the STC zone is applied, k is the LRU
index numbering from 0. That is, symbol index shall be reset to 0 when a new STC zone is applied. The first
subcarrier of the first LRU is numbered from 0.
If 2-stream interlaced pilot pattern A is used (cf. Figure 41 in [1]), then m = mod([symbol index] - [cyclic shift],
6), where cyclic shift = 0,1,2 for the three interlacing patterns, respectively.
For the type-1 subframe containing one idle symbol, the last OFDM symbol in Figure 2 is replaced with an idle
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IEEE C80216m-09/0156r1
symbol. For the type-2 subframe, the first OFDM symbol in Figure 2 is added as the 7th symbol.
Symbol Index
1
2
1
2
Subcarrier Index
Pilot Stream 0
1
1
2
2
Pilot Stream 1
1
1
2
2
Figure 2 ---- Pattern A for 1 or 2 pilot streams.
The modulated data symbols shall be sequentially mapped for two transmit antennas in LRU-first order. The
mapping inside one LRU continues first in an ascending manner along the subcarriers of the first OFDM symbol
and then proceeds to the next OFDM symbol in time. When the LRU boundary is reached, the mapping
proceeds to the next LRU. An illustration of the mapping rule for two transmit antennas is shown in Figure 3,
assuming six OFDM symbols in one LRU. For the type-1 subframe containing one idle symbol, the last OFDM
symbol in Figure 3 is replaced with an idle symbol. For the type-2 subframe containing seven symbols, the data
mapping is illustrated in Figure 4.
By comparing Figures 3~4 with Figure 1, we can see that the presented data mapping for SFBC aligns well with
the one specified for STBC in legacy 802.16e systems. Consequently, the legacy encoder and decoder of STBC
can be reused for SFBC by only adjusting the data mapping and de-mapping patterns.
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IEEE C80216m-09/0156r1
Symbol Index, antenna#1
Subcarrier Index
Symbol Index, antenna#0
S16
S32
S64
S80
S17
S33
S65
S81
-S17*
-S33*
-S65*
-S81*
S16*
S32*
S64*
S80*
S0
S18
S34
S48
S66
S82
S1
S19
S35
S49
S67
S83
-S1*
-S19*
-S35*
-S49*
-S67*
-S83*
S0*
S18*
S34*
S48*
S66*
S82*
S2
S20
S36
S50
S68
S84
S3
S21
S37
S51
S69
S85
-S3*
-S21*
-S37*
-S51*
-S69*
-S85*
S2*
S20*
S36*
S50*
S68*
S84*
S4
S22
S38
S52
S70
S86
S5
S23
S39
S53
S71
S87
-S5*
-S23*
-S39*
-S53*
-S71*
-S87*
S4*
S22*
S38*
S52*
S70*
S86*
S6
S24
S54
S72
S7
S25
S55
S73
-S7*
-S25*
-S55*
-S73*
S6*
S24*
S54*
S72*
S8
S26
S40
S56
S74
S88
S9
S27
S41
S57
S75
S89
-S9*
-S27*
-S41*
-S57*
-S75*
-S89*
S8*
S26*
S40*
S56*
S74*
S88*
S10
S28
S42
S58
S76
S90
S11
S29
S43
S59
S77
S91
-S91*
S10*
S28*
S42*
S58*
S76*
S90*
-S11*
-S29*
-S43*
-S59*
-S77*
S12
S30
S44
S60
S78
S92
S13
S31
S45
S61
S79
S93
-S13*
-S31*
-S45*
-S61*
-S79*
-S93*
S12*
S30*
S44*
S60*
S78*
S92*
S14
S46
S62
S94
S15
S47
S63
S95
-S15*
-S47*
-S63*
-S95*
S14*
S46*
S62*
S94*
Pilot subcarrier
for stream #0
Pilot subcarrier
for stream #1
Null subcarrier
Data subcarrier
Figure 3 ---- Data mapping example of SFBC for 2Tx antennas with six OFDM symbols in one LRU.
Symbol Index, antenna#1
Subcarrier Index
Symbol Index, antenna#0
S16
S32
S64
S80
S17
S33
S65
S81
-S17*
-S33*
-S65*
-S81*
S16*
S32*
S64*
S80*
S0
S18
S34
S48
S66
S82
S96
S1
S19
S35
S49
S67
S83
S97
-S1*
-S19*
-S35*
-S49*
-S67*
-S83*
-S97*
S0*
S18*
S34*
S48*
S66*
S82*
S96*
S2
S20
S36
S50
S68
S84
S98
S3
S21
S37
S51
S69
S85
S99
-S3*
-S21*
-S37*
-S51*
-S69*
-S85*
-S99*
S2*
S20*
S36*
S50*
S68*
S84*
S98*
S4
S22
S38
S52
S70
S86
S100
S5
S23
S39
S53
S71
S87
S101
-S5*
-S23*
-S39*
-S53*
-S71*
-S87*
-S101*
S4*
S22*
S38*
S52*
S70*
S86*
S100*
S6
S24
S54
S72
S102
S7
S25
S55
S73
S103
-S7*
-S25*
-S55*
-S73*
-S103*
S6*
S24*
S54*
S72*
S102*
S8
S26
S40
S56
S74
S88
S104
S9
S27
S41
S57
S75
S89
S105
-S9*
-S27*
-S41*
-S57*
-S75*
-S89*
-S105*
S8*
S26*
S40*
S56*
S74*
S88*
S104*
S10
S28
S42
S58
S76
S90
S106
S11
S29
S43
S59
S77
S91
S107
-S91*
-S107*
S10*
S28*
S42*
S58*
S76*
S90*
S106*
-S11*
-S29*
-S43*
-S59*
-S77*
S12
S30
S44
S60
S78
S92
S108
S13
S31
S45
S61
S79
S93
S109
-S13*
-S31*
-S45*
-S61*
-S79*
-S93*
-S109*
S12*
S30*
S44*
S60*
S78*
S92*
S108*
S14
S46
S62
S94
S110
S15
S47
S63
S95
S111
-S15*
-S47*
-S63*
-S95*
-S111*
S14*
S46*
S62*
S94*
S110*
Pilot subcarrier
for stream #0
Pilot subcarrier
for stream #1
Null subcarrier
Data subcarrier
Figure 4 ---- Data mapping example of SFBC for 2Tx antennas with seven OFDM symbols in one LRU.
3. Data mapping for uplink SFBC
According to the current SDD [1], the downlink 18x6 pilot pattern shown in Figure 2 is also applicable to the
uplink 18x6 pilots. Therefore, the data mapping rule for SFBC illustrated in Figures 3~4 can also be used for the
uplink.
In addition, for the 6x6 uplink tile (cf. Figure 45 in [1]) and the uplink physical structure for legacy support (cf.
Figures 46~47 in [1]), we can define the data mapping for SFBC similarly based on the following rule: The
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IEEE C80216m-09/0156r1
modulated data symbols shall be sequentially mapped for two transmit antennas in LRU-first order. When the
LRU boundary is reached, the mapping proceeds to the next LRU. The mapping inside one LRU is performed in
tile-first order and inside one tile the mapping continues first in an ascending manner along the subcarriers of
the first OFDM symbol and then proceeds to the next OFDM symbol in time. When the tile boundary is reached,
the mapping proceeds to the next tile.
4. Proposed SDD text
------------------------------------------- Start of Proposed SDD Text -----------------------------------------------------11.8 DL MIMO Transmission Scheme
11.8.2.1.1 Open-loop SU-MIMO
11.8.2.1.1.1 Transmit Diversity
……
The MIMO encoder generates the SFBC matrix
s
z 1
 s2
 s2* 
 , Equation 6
s1* 
Then the output of the MIMO encoder is multiplexed by NTx2 matrix W, where W is described in section
11.8.2.1.1.
The 2-stream pilot pattern A is shown in Figure 40, and the pilot locations are expressed by
Pilot Location for Stream #0 = 18*k – 8*mod(m+2,3) + 16
Pilot Location for Stream #1 = 18*k – 8*mod(m+2,3) + 17
Where m = [symbol index], symbol index 0 is the first symbol in which the STC zone is applied, k is the LRU
index numbering from 0. That is, symbol index shall be reset to 0 when a new STC zone is applied. The first
subcarrier of the first LRU is numbered from 0.
If 2-stream interlaced pilot pattern A is used as shown in Figure 41, then m = mod([symbol index] - [cyclic
shift], 6), where cyclic shift = 0,1,2 for the three interlacing patterns, respectively.
The modulated data symbols shall be sequentially mapped for two transmit antennas in LRU-first order. The
mapping inside one LRU continues first in an ascending manner along the subcarriers of the first OFDM symbol
and then proceeds to the next OFDM symbol in time. When the LRU boundary is reached, the mapping
proceeds to the next LRU. An illustration of the mapping rule for two transmit antennas is shown in Figure x,
assuming pilot pattern A with up to seven OFDM symbols in one LRU. For the general type-1 subframe, the
seventh OFDM symbol is removed in Figure x. For the type-1 subframe containing one idle symbol, the seventh
OFDM symbol is removed and the sixth OFDM symbol in Figure x is replaced with an idle symbol.
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IEEE C80216m-09/0156r1
Symbol Index, antenna#1
Subcarrier Index
Symbol Index, antenna#0
S16
S32
S64
S80
S17
S33
S65
S81
-S17*
-S33*
-S65*
-S81*
S16*
S32*
S64*
S80*
S0
S18
S34
S48
S66
S82
S96
S1
S19
S35
S49
S67
S83
S97
-S1*
-S19*
-S35*
-S49*
-S67*
-S83*
-S97*
S0*
S18*
S34*
S48*
S66*
S82*
S96*
S2
S20
S36
S50
S68
S84
S98
S3
S21
S37
S51
S69
S85
S99
-S3*
-S21*
-S37*
-S51*
-S69*
-S85*
-S99*
S2*
S20*
S36*
S50*
S68*
S84*
S98*
S4
S22
S38
S52
S70
S86
S100
S5
S23
S39
S53
S71
S87
S101
-S87*
-S101*
S4*
S22*
S38*
S52*
S70*
S86*
S100*
-S5*
-S23*
-S53*
-S71*
S6
S24
-S39*
S54
S72
S102
S7
S25
S55
S73
S103
-S7*
-S25*
-S55*
-S73*
-S103*
S6*
S24*
S54*
S72*
S102*
S8
S26
S40
S56
S74
S88
S104
S9
S27
S41
S57
S75
S89
S105
-S9*
-S27*
-S41*
-S57*
-S75*
-S89*
-S105*
S8*
S26*
S40*
S56*
S74*
S88*
S104*
S10
S28
S42
S58
S76
S90
S106
S11
S29
S43
S59
S77
S91
S107
-S107*
S10*
S28*
S42*
S58*
S76*
S90*
S106*
-S11*
-S29*
-S43*
-S59*
-S77*
-S91*
S12
S30
S44
S60
S78
S92
S108
S13
S31
S45
S61
S79
S93
S109
-S13*
-S31*
-S45*
-S61*
-S79*
-S93*
-S109*
S12*
S30*
S44*
S60*
S78*
S92*
S108*
S14
S46
S62
S94
S110
S15
S47
S63
S95
S111
-S15*
-S47*
-S63*
-S95*
-S111*
S14*
S46*
S62*
S94*
S110*
Pilot subcarrier
for stream #0
Pilot subcarrier
for stream #1
Null subcarrier
Figure x ---- Data mapping example of SFBC for 2Tx antennas using pilot pattern A with up to 7 OFDM symbols in one LRU.
11.12 UL MIMO Transmission Scheme
11.12.2.1.1 Open-loop SU-MIMO
11.12.2.1.1.1 Transmit Diversity
……
The MIMO encoder generates the SFBC matrix
s
z 1
 s2
 s2* 
 , Equation 14
s1* 
Then the output of the MIMO encoder is multiplexed by NTx2 matrix W, where W is described in section
11.12.2.1.1.
The downlink 18x6 pilot pattern shown in Figure 40 is also applicable to the uplink 18x6 pilots. The data
mapping rule for SFBC illustrated in Figure x is also used for the uplink.
For the 6x6 uplink tile and the uplink physical structure for legacy support, the data mapping for SFBC is
defined similarly. The modulated data symbols shall be sequentially mapped for two transmit antennas in LRUfirst order. When the LRU boundary is reached, the mapping proceeds to the next LRU. The mapping inside one
LRU is performed in tile-first order and inside one tile the mapping continues first in an ascending manner along
the subcarriers of the first OFDM symbol and then proceeds to the next OFDM symbol in time. When the tile
boundary is reached, the mapping proceeds to the next tile.
------------------------------------------- End of Proposed SDD Text ------------------------------------------------------
References
[1] IEEE 802.16m-08/003r6, “The Draft IEEE 802.16m System Description Document.”
[2] IEEE P802.16Rev2/D8, December 2008.
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