Dl fdma considerations
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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

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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.


Dl throughput per a sta without considerations on upper layer protocols

Katsuo Yunoki, KDDI R&D Labs.

DL Throughput per a STAwithout considerations on upper layer protocols

Throughput (Mbps)

MPDU size (byte)


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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