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DL-FDMA considerations. Authors:. Date: 2014-09-12. Abstract. This contribution considered Down Link FDMA (DL-FDMA) as a candidate technique for access efficiency improvement for 11ax. Conceptions. AP 20MHzBW * 4CH f requency d ivision m ultiplex transmission (in case of 80MHzBW totally)

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dl fdma considerations
DL-FDMA considerations

Authors:

  • Date:2014-09-12

Katsuo Yunoki, KDDI R&D Labs.

abstract
Abstract
  • This contribution considered Down Link FDMA (DL-FDMA) as a candidate technique for access efficiency improvement for 11ax.

Katsuo Yunoki, KDDI R&D Labs.

conceptions
Conceptions
  • AP
    • 20MHzBW * 4CH frequency division multiplex transmission (in case of 80MHzBWtotally)
    • Up to 4 data streams to 4 STAs are available
    • 4 concurrent ACKs on different 4 * 20MHz CH
  • STAs
    • Data streams on 4 channels will be received and demodulated in parallel
    • Target data streams are recognized by destination address in MAC header
    • STA will reply ACK using channels which included the data stream to the STA

Katsuo Yunoki, KDDI R&D Labs.

figure of conceptions dl fdma ap 4 stas
Figure of ConceptionsDL-FDMA: AP  4 STAs

DIFS

+ CW

SIFS

Ex.

CCA

Data to STA-1

AP

CH36

t

STA-1

ACK

CCA

Data to STA-2

AP

t

CH40

STA-2

ACK

CCA

Data to STA-3

AP

CH44

t

STA-3

ACK

CCA

Data to STA-4

AP

CH48

t

STA-4

ACK

Katsuo Yunoki, KDDI R&D Labs.

sequence by the current standards
Katsuo Yunoki, KDDI R&D Labs.Sequence by the current standards

DIFS

+CW

DIFS

+CW

DIFS

+CW

DIFS

+CW

SIFS

SIFS

SIFS

SIFS

AP

Data

Data

Data

Data

ACK

STA1

ACK

STA2

ACK

STA3

ACK

STA4

Medium time for a set of data deliveries to 4 STAs

sequence by this proposal dl fdma
Katsuo Yunoki, KDDI R&D Labs.Sequence by this proposal(DL-FDMA)

DIFS

+CW

SIFS

Data1

Data2

AP

Data3

Data4

STA1

ACK

Simultaneous 4 ACKs are responded on different 4 frequency channels.

STA2

ACK

STA3

ACK

ACK

STA4

Medium time for a set of data deliveries to 4 STAs

medium time comparison data delivery to 4 stas
Katsuo Yunoki, KDDI R&D Labs.Medium Time Comparison(Data delivery to 4 STAs)

Medium time usage is reduced.

Medium Time (us)

MPDU size (byte)

Refer to Slide-12 for details.

available bandwidth
Available Bandwidth

Interference

80MHz

40MHz

0MHz

20MHz

CH

Primary 20M

Primary 20M

Primary 20M

36

36

36

36

Secondary 20M

Secondary 20M

11ac

(80M*1)

40

40

40

40

Secondary 40M

44

44

44

44

48

48

48

48

80MHz

60MHz

60MHz

60MHz

CH

36

36

36

36

FDMA

(20M*4)

40

40

40

40

44

44

44

44

48

48

48

48

FDMA may also have some advantages on available bandwidth in densely deployed environment.

Katsuo Yunoki, KDDI R&D Labs.

mixed operation with legacy stas
Mixed Operation with Legacy STAs

This FDMA concept may be applicable for mixed operation with legacy STAs. The primary 20MHz channel would be used for a legacy STA on a priority basis and other channels for 11ax supported STAs. It might improve access efficiency of legacy STAs too.

CH

for a legacy STA

36

Primary 20M

FDMA

(20M*4)

40

for 11ax STAs

44

48

Katsuo Yunoki, KDDI R&D Labs.

summary
Summary
  • FDMA may have some advantages in access efficiency on:
    • Less medium time,
    • Shorter latency,
    • Wider available bandwidth in dense environment,
    • Mixed operation with legacy STAs
  • Detailed considerations is needed for feasibility study.

Katsuo Yunoki, KDDI R&D Labs.

straw poll
Straw poll
  • Do you support to study DL-FDMA as a possible technique for efficiency improvement for 11ax?
  • Y/N/A =

Katsuo Yunoki, KDDI R&D Labs.

backup medium time of frames
BackupMedium Time of Frames

40us

8us

8us

4us

8us

4us

4us

4us

L-STF

L-LTF

L-SIG

VHT-SIG-A

VHT-

STF

VHT-

LTF

VHT-

SIG-B

Data

  • Data Frame [us]

40 + {(Service + MPDU + PHY pad + Tail) / NDBPS}* 4

= 40 + roundup{(16 + MPDU[byte]*8 + 6) / NDBPS}* 4

MPDU includes MAC header (26 bytes).

  • ACK Frame [us]

40 + {(Service + MPDU(ACK frame) + PHY pad + Tail) / NDBPS}* 4

= 40 + roundup{(16 + 14*8 + 6) / NDBPS}* 4

NDBPS: the number of data bits per OFDM symbol

Katsuo Yunoki, KDDI R&D Labs.

references
References
  • [1] Brian Hart et al, IEEE 11-14/855r0, “Techniques for Short Downlink Frames”

Katsuo Yunoki, KDDI R&D Labs.

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