IEEE C802.16m-09/2065
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposed Changes to Frame Structure for 7 MHz Channel Bandwidth with 1/8 Tb CP
(15.3.3)
Date
Submitted
2009-08-30
Source(s)
Jin Sam Kwak, HanGyu Cho, Dongguk
Ihm
Voice : +82-31-450-7902
E-mail: samji@lge.com
LG Electronics
Jaeweon Cho, Hokyu Choi
Samsung Electronics Co., Ltd.
+82-31-279-5796
jaeweon.cho@samsung.com
Re:
IEEE 802.16m-09/0045, IEEE 802.16 Working Group Letter Ballot #30
Abstract
This contribution proposes some changes of the TDD and FDD frame structures for 7MHz
system bandwidth with 1/8 Tb CP. In order to avoid the Type-3 subframe in the uplink, it is
desirable to configure the frame by using the Type-1 and Type-2 subframes with a commonality
between TDD and FDD frame structures.
Purpose
To be discussed and adopted by TGm.
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
discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The
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>.
Proposed Changes to Frame Structure for 7 MHz Channel Bandwidth
with 1/8 Tb CP (15.3.3)
Jin Sam Kwak, HanGyu Cho, Dongguk Ihm
LG Electronics
Jaeweon Cho, Hokyu Choi
Samsung Electronics Co., Ltd.
1
IEEE C802.16m-09/2065
1. Introduction
This contribution proposes some changes of the frame structure for 7MHz channel bandwidth in the IEEE
P802.16m/D1 [1]. The current frame structure for 7MHz bandwidth with G =1/8 includes TWO Type-3
subframes among 7 subframes in each DL/UL frame for FDD mode. In order to not make a new design of UL
control channels for supporting 5-symbol subframe, it is necessary to re-configure the frame with 1/8 Tb CP by
using the Type-1 and Type-2 subframes, along with the commonality between TDD and FDD frame structures.
2. Proposed Frame Structure for the 7 MHz bandwidth with G =1/8
2.1 Design Criteria
In the IEEE P802.16m/D1, four types of subframes have been defined, i.e., type-1 with 6 symbols, type-2 with 7
symbols, type-3 with 5 symbols, and type-4 with 9 symbols. Therefore, the main rule of re–design of frame
structure for 7 MHz with G = 1/8 is to use two types of subframes, i.e., Type-1 and Type-2 subframes, for
accommodating 34 (33) OFDMA symbols in a FDD (TDD) frame. Here are our summarized design criteria:
 A new frame structure should be designed by type-1 and type-2 subframes, excluding type-3 and type-4
subframes.
 New subframe type definitions and additional PHY design for support the extended usage of the
existing type of subframe should be avoided. It should be considered that the utilization of type-4
subframe is limited to the frame structure for 8.75 MHz in the legacy support mode.
 A new frame structure should support the WirelessMAN-OFDMA for the 7 MHz channel bandwidth
with 12 UL OFDMA symbols.
 There should be commonalities between TDD and FDD frame structure.
 The switching point of TDD frame structure having a CP length of 1/8 Tb should be aligned with that of
the Advanced Air Interface frame with a CP length of 1/16 Tb in IEEE P802.16m/D1 [1].
2.2 Proposed Frame structure for CP = 1/8 Tb
Figure 1 shows examples of the proposed TDD and FDD frame structure. In FDD, there are one type-1
subframe and four type-3 subframes with 7 OFDMA symbols. The single type-1 subframe is located in the first
DL subframe for SFH transmission and other subframes are type-3 subframes. The TDD frame structure has a
commonality with the FDD frame structure in the number of subframes, and, since one OFDMA symbol should
be an idle symbol for transition time, two subframes can be configured as the type-1 subframe, and three
subframes should be configured as the type-3 subframe with a TTG of 188 us and a RTG of 60 us, which are
exactly the same as those in the WiMAX profile.
2
IEEE C802.16m-09/2065
TTG:188.0
2060
7 MHz
1/8 Tb
TDD (2:3)
2880 (20 symbols)
1872 (13 symbols)
(7)
(6)
(7)
(6)
1
RTG : 60.0
(7)
(7)
TTG:188.0
3068
7 MHz
1/8 Tb
TDD (3:2)
1872 (13 symbols)
2880 (20 symbols)
(7)
(6)
(7)
(6)
1
RTG : 60.0
(7)
(7)
7 MHz
1/8 Tb
FDD
Idle : 104
4896 (34 symbols)
(7)
(6)
(7)
(7)
(7)
5000 (us)
Figure 1 Examples of TDD and FDD Frame Structures with a CP of 1/8 Tb
2.3 Frame Structure for Legacy Support
In order to support the legacy system in the TDD frame structure, it is necessary to consider the switching point
alignment with 12 UL OFDMA symbols and to allow the coexistence with the 16m systems operating with
other CP length. Figure 2 shows examples of the proposed frame structure in the legacy support mode and
coexistence with 1/16 Tb CP length.
802.16m in Legacy-Support Mode (Tg = 1/8 Tb)
TTG:188.0
3212
7 MHz
1/8 Tb
TDD (3:2)
3024 (21 symbols)
Legacy Zone
1728 (12 symbols)
16m Zone
1
3128 (23 symbols)
(6)
(6)
(6)
TTG:180
3308
7 MHz
1/16 Tb
TDD (4:2)
(6)
1632 (12 symbols)
(5)
(6)
1
(6)
RTG : 60.0
(6)
5000 (us)
Figure 2 Examples of TDD Frame Structures in the legacy support mode
In addition, by using the “FRAME-OFFSET” and the fixed number of DL/UL subframes, it is natural to define
the legacy DL zone as 3+9·(FRAME_OFFSET - 1) in order to maintain the concept that all subframes in 16m
DL zone consists of the same type, i.e., type-1 subframes.
3
IEEE C802.16m-09/2065
3. References
[1] IEEE P802.16m/D1, “DRAFT Amendment to IEEE Standard for Local and Metropolitan Area Networks
Part16: Air Interface for Broadband Wireless Access Systems.”
4. Text proposals for the IEEE P802.16m/D1
============================== Start of Proposed Text =================================
[Remedy #1: Adopt the following changes to the text and illustration for Figure 391 on page 243 in line 32
(Section 15.3.3.2.1)]
Figure 391 illustrates an example FDD frame structure, which is applicable to the nominal channel bandwidth
of 7 MHz with G = 1/8. Four subframes among six five subframes are the type-12 subframes, and the other two
one subframes are the type-31 subframe. The third and forth subframes are the type-3 subframe.
Superframe: 20 ms (4 frames, 20 subframes)
UL/DL PHY Frame 5ms (subframe + idle time)
F0
F1
F2
F3
Idle time : 104 us
UL/DL PHY Subframe 0.864 ms
UL/DL PHY Subframe 0.720 ms
DL/UL
SF2 (6)
DL/UL
SF0 (6)
DL/UL
SF3 (5)
DL/UL
SF4 (5)
DL/UL
SF6 (6)
DL/UL
SF5 (6)
One OFDAM Symbol
One OFDAM Symbol
s0
s0
s1
s2
s3
s4
s1
s2
s5
Type-3 subframe
CP = 1/8 Tb
Type-1 subframe
CP = 1/8 Tb
4
s3
s4
IEEE C802.16m-09/2065
Superframe: 20 ms (4 frames, 20 subframes)
UL/DL PHY Frame 5ms (subframe + idle time)
F0
F1
F2
F3
Idle time : 104 us
UL/DL PHY Subframe 1.008 ms
UL/DL PHY Subframe 0.864ms
DL/UL
SF0 (6)
DL/UL
SF2 (7)
DL/UL
SF1 (7)
DL/UL
SF4 (7)
DL/UL
SF3 (7)
One OFDMA Symbol
One OFDAM Symbol
s0
s0
s1
s2
s3
s4
s1
s2
s3
s4
s5
s6
s5
Type-2 subframe
Type-1 subframe
CP = 1/8 Tb
CP = 1/8 Tb
Figure 391 — Frame structure for 7 MHz FDD mode (G = 1/8)
[Remedy #2: Adopt the changes to the following text on page 244 in line 46 (Section 15.3.3.2.2)]
In a TDD frame with DL to UL ratio of D:U, the 1st contiguous D subframes and the remaining U subframes are
assigned for DL and UL, respectively, where D + U = 8 for 5, 10 and 20 MHz channel bandwidths, D + U = 7
for 8.75 MHz channel bandwidth, and D + U = 65 for 7 MHz channel bandwidth.
[Remedy #3: Adopt the following changes to the text and illustration for Figure 394 on page 245 in line 36
(Section 15.3.3.2.2)]
Figure 394 illustrates an example TDD frame structure with D:U = 43:2, which is applicable to the nominal
channel bandwidths of 7 MHz with G = 1/8. Three subframes among six five subframes are the type-12
subframes, and the other three two subframes are the type-31. The second, third and forth DL subframes are the
type-3 subframe. TTG and RTG are 188μs and 60μs, respectively.
5
IEEE C802.16m-09/2065
Superframe: 20 ms (4 frames, 20 subframes)
UL/DL PHY Frame 5ms (5 subframes)
F0
F1
F2
F3
Switching points for DL:UL=4:2
RTG
TTG
DL
SF1 (5)
DL
SF0 (6)
DL
SF2 (5)
UL
SF4 (6)
DL
SF3 (5)
UL
SF5 (6)
Subframe length = 6 full OFDM symbols = 0.864 ms
s0
s1
s2
s3
s4
s5
Subframe length = 5 full OFDM symbols = 0.720 ms
Type-1 subframe
s0
s1
s2
s3
CP = 1/8 Tb
s4
Type-3 subframe
Superframe: 20 ms (4 frames, 20 subframes)
UL/DL PHY Frame 5ms (5 subframes)
F0
F1
F2
F3
Switching points for DL:UL=3:2
RTG
TTG
UL
SF0 (6)
DL
SF1 (7)
DL
SF2 (7)
UL
SF3 (6)
DL
SF4 (7)
Subframe length = 6 full OFDM symbols = 0.864 ms
Subframe length = 7 full OFDM symbols = 1.008 ms
s0
s0
s1
s2
s3
s4
s3
s4
s1
s2
Type-1 subframe
s3
s4
s5
CP = 1/8 Tb
Type-2 subframe
Figure 394 — Frame structure for 7 MHz TDD mode
[Remedy #4: Adopt the changes to the following text on page 254 in line 45 (Section 15.3.3.4.2)]
When the Advanced Air Interface frames support the WirelessMAN-OFDMA for the 8.75 MHz channel
bandwidth with 15 UL OFDM symbols and for the 7 MHz channel bandwidth with 12 UL OFDM symbols, all
subframes in the Advanced Air Interface DL Zone are type-1 subframe. The number of symbols in the
WirelessMAN-OFDMA DL Zone is 3+6·(FRAME_OFFSET - 1) for 8.75 MHz and 9+6·(FRAME_OFFSET 1) for 7 MHz.
============================== End of Proposed Text =================================
6