1. Uplink Subframe Aggregation
IEEE Presentation Submission Template (Rev. 9)
Document Number:
IEEE S802.16maint-08/215
Date Submitted:
Source:
Sten Sjoberg, Havish Koorapaty
Ericsson AB
Venue:
IEEE Session #55
Base Contribution:
IEEE C802.16maint-08/215r1
Purpose: To propose uplink subframe aggregation in A logical aggregation of consecutive UL subframes to carry one MAC PDU to get improved cell coverage and to increase effective uplink data rates seen at the cell edge
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2. Uplink Subframe Aggregation
This contribution introduces a new logical concept into the UL transmission. The proposal introduces an optional logical aggregation of consecutive UL subframes to carry one MAC PDU burst.
This addresses improved cell coverage and increases effective uplink data rates at the cell edge.

3. The UL problem
Large imbalance in BS and MS Tx powers
Transmission only a fraction of the time, equals a relatively low energy per burst
Large MAC PDU overhead (10 bytes minimum OH per burst with ARQ, 22 bytes OH if CMAC is used)
Fragmentation inefficient for low rate communication (due to high MAC OH)

4. Proposal
Introduce the option of aggregating multiple UL subframes into one logical unit for modulation and decoding, where one UL MAC PDU may span over multiple frames such that enough symbol energies are accumulated for better coverage and larger payload can be accomodated for better efficiency.

5. Proposed Uplink Subframe Aggregation
Example of transmission with aggregated uplink subframes
(the same color/pattern represents one logical uplink data burst)

6. Gains by aggregation (example) 35:12, QPSK rate ½, 2 repetitions
# of aggregated subframes
(one subch)
Total PHY payload bits
MAC overhead
MAC PDU payload
PHY data rate
Effective data rate 1 96 80 16
19.2 kbps
3.2 kbps 2
192
112
11.2 kbps
(3.5x)
(5.4 dB) 3
288
208
13.86 kbps
(4.3x)
(6.3 dB) 4
384
304
15.2 kbps
(4.75x)
(6.8 dB)

7. Proposed Text Additions
Add a new UL-MAP Extended-2 IE Section Aggregated UL-MAP IE
Add text at the end of section UL transmission allocations
Add section Segmentation for UL Frame Aggregation
Add capability to OFDMA MAP Capability
Please see contribution C802.16maint-08/215r1or higher revision for the actual text proposal.