Transcript IEEE C802.16m-10/0017

Comparisons on Frame Structures for Supporting WirelessMAN-OFDMA (16.3.3.7)
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-10/0017
Date Submitted:
2010-01-11
Source:
Dongguk Lim, HanGyu Cho, Jin Sam Kwak
Email: {dongguk.lim, hg.cho, jinsam.kwak } @lge.com
LG Electronics
Re:
IEEE 802.16m-09/0045, IEEE 802.16 Working Group Letter Ballot #30b
Venue:
IEEE Session #65
Base Contribution:
IEEE C802.16m-10/0017
Purpose:
To be discussed and adopted by TGm.
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Comparisons on Frame Structures
for Supporting WirelessMAN-OFDMA
Contents
 Introduction
 Frame Structure for supporting WirelessMAN-OFDMA in D3
 Further Consideration Points: Midamble Transmission, 1-
subframe for MZone, Subframe Alignment, etc
 Possible Options for Legacy Support
 Option I: Utilization of the type-2 subframe
 Option II: SFH allocation in 4 OFDMA symbols
 Option III: Decoupling b/w subframe & midamble allocation
 Text proposal
 References
Introduction
 Frame Structure for supporting both WirelessMAN-OFDMA MSs & AMSs
•
ABS supports the mixed operation for supporting both 16e and 16m MSs
 In D3, there are two types of frame configurations for legacy support:
 Separated by two zones only: L-zone and M-zone (Fixed zone allocation)
 Separated by multiple zone switches (Flexible zone allocation)

A support of coexistence with fixed zone allocation in the neighbor BS
- Fixed zone allocation
L-zone
- Multiple switching mode
L-zone
M-zone
M-zone
L-zone
Frame configurations for mixed mode support
Frame Structure for supporting WirelessMAN-OFDMA
 Further Considerations on Frame Configurations for Legacy Support
•
•
Not support all possible ratio of L-zone and Mzone
 At least two subframes are allocated for Mzone:
 If only one subframe is allocated to Mzone, midamble cannot be
transmitted in M-zone. This is because the type-1 subframe cannot
include all control signals, i.e., A-Preamble, SFH and Midamble.
Not align with 16m-only frame structure (Not maintain the commonality)
 Since a type-3 subframe for 5/10/20 MHz with 1/8 Tu CP should be
allocated in Lzone, there are all type-1 subframes in Mzone.
 In the legacy support mode, the subframe configuration (or order) is
different from the 16m-only mode.
 To resolve the above issues in mixed mode operation, we can consider several
options as follows:
•
•
•
Option I: Utilization of type-2 subframe
Option II: Control/data allocation in 4 OFDMA symbols
Option III: Decoupling b/w subframe & midamble allocation
Option I : Utilization of type-2 subframe
 A-Preamble + SFH + Midamble in Type-2 Subframe
•
The control signals such as A-Preamble, SFH and Midamble can be
transmitted in one subframe in Mzone at the same time.
 The type-2 subframe is always allocated to Mzone and the first subframe
of Mzone is a type-2 subframe.
 There is no coverage issue of SFH by using the same structure, i.e.,
resource size & code rate, in the 16m-only mode.
 The commonality with 16m-only FS is destroyed due to the type-2 & type3 subframes in the Mzone.
Option II: Control/data allocation in 4 OFDMA symbols
 A-Preamble + SFH + Midamble in Type-1 Subframe
•
In order to transmit A-Preamble, SFH and Midamble in the type-1 subframe,
the SFH allocation should be allocated in 4 OFDMA symbols as a reservation of
one OFDMA symbol for transmitting midamble.
 There is a coverage loss of SFH due to the limited resources for new SFH structure. It
is necessary to verify the SFH coverage in 4 OFDMA symbols.
•
In the subframe containing A-Preamble and midamble, it is necessary to allow
to allocate 4 OFDMA symbols for normal data/control channels.
 In this case, since the current type-3 subframe can transmit the midamble, there is
no need to change the current frame structure if Mzone occupies more than 2
subframes.
Option III: Decoupling b/w subframe & midamble allocation
 A Midamble is transmitted just before Type-1 subframe which can
accommodate A-Preamble and SFH in the manner of 16m-only mode.
•
•
•
•
Subframe-level alignment: The frame for 16m AMS in the mixed mode starts
from the same subframe boundary in the 16m-only TDD FS.
The midamble is transmitted just before the start of 16m frame.
The number of symbols in the first Lzone is the same in D3. There is no change
of definition of Lzone by using one symbol in type-1 subframe as a midamble.
The only modification is to add type-3 subframe in Mzone if the number of
subframes in Mzone is larger than 1 as in D3.
Summary (1/3)
 Option I
• Pros.
 All control signal, i.e., A-Preamble, SFH, Midamble, can be
transmitted through one subframe (Type-2 subframe).
 Support the variable ratio of L-zone and M-zone
• Cons.
 Impacts on the current frame structure
 Due to generation of Type -2 subframe, type-3 subframe should be
located in Mzone.
 Different frame configuration with 16m only (not maintain
commonality)
 Impact on the UL control channel structure in FDD
 5 symbol UL subframe
 The subframe alignment with 16m-only frame structure is broken.
Summary (2/3)
 Option II
• Pros.
 All control signal, i.e., A-Preamble, SFH, Midamble, can be
transmitted through one subframe (Type-1 subframe).
 Support the variable ratio of L-zone and M-zone
 Maintain the commonality with 16m-only FS
• Cons.
 Need a new design of SFH structure
 Due to 4-OFDMA symbols for SFH, the coverage loss is not avoidable.
 Not possible to use the remaining resource in SFH subframe for
data/A-MAP transmission
 The 4-OFDMA symbol should be also used for data/control
transmission in the subframe not transmitting the SFH. It is the
same to design a new type of subframe.
 The subframe alignment with 16m-only frame structure is broken.
Summary (3/3)
 Option III
•
Pros.
 Maintain the commonality with 16m-only frame structure
 The 16m-only FS is directly extended to Lzone & Mzone configuration.
 Subframe alignment with 16m-only frame structure can be achieved.
 No impact on resource allocation for Lzone in D3
 All possible ratios of L-zone and M-zone are supported.
 Not need to allocate the subframe for midamble transmission in legacy
support
•
Cons.
 Even though the frame offset (the definition of 16m frame) is not changed,
the Mzone in DL starts with midamble.
 Considering commonality and subframe alignment with 16m-only frame
structure, Option III is more suitable than Option I or II for midiamble
transmission and 1-subframe allocation for Mzone in legacy support mode.