11 02 0138-00-0wng throughput analysis for ieee 802 11a higher data rates

8/11/2019 11 02 0138-00-0wng Throughput Analysis for Ieee 802 11a Higher Data Rates

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doc.: IEEE 802.11-02/138r0

Submission

March 2002

Yang Xiao and Jon Rosdahl , Micro LinearSlide 1

Throughput Analysis forIEEE 802.11a Higher Data

Rates

Yang Xiao and Jon Rosdahl

Micro L inear Co.


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


Agenda

Assumptions

Throughput Formulations

IEEE 802.11a parameters

Numerical Results

Improved Performance

AssumptionsNumerical Results

Conclusions


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


Assumptions

Data rates higher than 54Mbps have the

same set of overhead parameters as in IEEE

802.11a.

There are only two nodes in the BSS: one is

the sender and the other is the receiver.

The sender always has packets to send.


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doc.: IEEE 802.11-02/138r0

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March 2002


Throughput Formulations

ACKDSIFSDATADDIFSslot

DATA

TTTTTCW

LThroughput

__min

2

8

DBPS

DATASYMPHYHeambleDATAD

N

LCeilingTTTT

828*8616*_Pr_

DBPS

SYMPHYHeambleACKDN

CeilingTTTT14*8616

*_Pr_

delaynpropagatio:

symbolaoftimeontransmissi:

header,PHYoftimeontransmissi:

symbol,OFDMperbitsdata:

_

SYM

PHYH

DBPS

T

T

N


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


IEEE 802.11a parameters

In numerical results:

(data rate, control rate) is (6,6), (9,6), (12, 12), (18, 12), (24, 24), (36, 24), (48, 24)or (54, 24) for IEEE 802.11a.

For data rates > 54Mps , both data rate and control rate are increased proportionally.

Table 1 Data Rates for the IEEE 802.11a

Data Rate (Mbps) Modulation NDBPS

6 BPSK 24

9 BPSK 36

12 QPSK 48

18 QPSK 72

24 16-QAM 96

36 16-QAM 144

48 64-QAM 192

54 64-QAM 216

,1,4,4,16

1023,,15,34,16,9

_Pr

maxmin

ssTsTsT

CWCWsTsTsT

SYMPHYHeamble

DIFSSIFSslot


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doc.: IEEE 802.11-02/138r0

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March 2002


Throughputs for Higher Data Rates (HDR)

Data Rate Throughput

54Mbps 30.34Mbps

108Mbps 42.93Mbps

216Mbps 52.75Mbps

For 1500 bytes Payload

The throughput is quite

small compared to the datarate.

0 500 1000 15000

10

20

30

40

50

60

Packet Size (Bytes)

Throughput(Mbps)forhighe

rdatarates

6Mbps9Mbps12Mbps18Mbps24Mbps36Mbps48Mbps54Mbps72(=2*36)Mbps96(=2*48)Mbps108(=2*54)Mbps

144(=3*48)Mbps162(=3*54)Mbps192(=4*48)Mbps216(=4*54)Mbps


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


Bandwidth Efficiency (BE) for HDR

Data Rate BE

6Mbps 89.8%

54Mbps 56.2%

108Mbps 39.75%

216Mbps 24.4%


BE is defined as thethroughput divided by thedata rate.

BE decreases as data rateincreases.0 500 1000 15000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Packet Size (Bytes)

BandwidthEfficiencyforhighe

rdatarates

6Mbps9Mbps12Mbps18Mbps24Mbps36Mbps48Mbps54Mbps72(=2*36)Mbps96(=2*48)Mbps

108(=2*54)Mbps144(=3*48)Mbps162(=3*54)Mbps192(=4*48)Mbps216(=4*54)Mbps


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doc.: IEEE 802.11-02/138r0

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March 2002


Throughput Increases for doubling rates

Data Rate Increase

2*6Mbps 4.65Mbps

2*54Mbps 12.59Mbps


Increase as compared to theoriginal ones.

0 500 1000 15000

2

4

6

8

10

12

14

Packet Size (Bytes)

T

hroughputincrease(Mbps)fordoub

lingdatarates

12(=2*6)Mbps18(=2*9Mbps24(=2*12)Mbps36(=2*18)Mbps48(=2*24)Mbps72(=2*36)Mbps96(=2*48)Mbps108(=2*54)Mbps


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doc.: IEEE 802.11-02/138r0

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Throughput Increase (%) for doubling Rates

Data Rate Increase

2*54Mbps 41.5%

41.5% is far from

doubled, i.e. 100%

increase


0 500 1000 15000

10

20

30

40

50

60

70

80

90

Packet Size (Bytes)

Throughputincrease(%)fordoublingdatarates

12(=2*6)Mbps18(=2*9Mbps24(=2*12)Mbps36(=2*18)Mbps48(=2*24)Mbps72(=2*36)Mbps96(=2*48)Mbps108(=2*54)Mbps


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Throughput Increases (%)

for Tripling/Quadrupling Rates

Data Rate Increase (%)

144Mbps 68.4%

162Mbps 65.1%

192Mbps 86.2%

216Mbps 77%

The increased rates are farfrom tripling/Quadrupling,i.e. 200% or 300% increase.


0 500 1000 15000

10

20

30

40

50

60

70

80

90

Packet Size (Bytes)

Throughputincrease(%)fortripling/qu

adruplingdatarates

144(=3*48)Mbps162(=3*54)Mbps192(=4*48)Mbps216(=4*54)Mbps


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doc.: IEEE 802.11-02/138r0

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March 2002


Improved Performance: Assumptions

A specific method to reduce the overhead is

not proposed in the presentation.

Under the assumption that the overhead can

be reduced, the improved performance

follows.

In particular, assume that all the overheadscan be reduced by 10%, 30%, and 50%.


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


Throughputs for HDR with overheads reduced

For 1500 bytes PayloadData rate: 6Mbps

Overhead

Reduced

Throughput

0% 5.39Mbps

10% 5.44Mbps

30% 5.55Mbps

50% 5.66Mbps0 500 1000 15000

1

2

3

4

5

6

Packet Size (Bytes)

Throughput(Mbps)forhigh

erdatarates

6Mbps6Mbps with 10% overheads reduced6Mbps with 30% overheads reduced6Mbps with 50% overheads reduced


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Overhead

Reduced

Throughput

0% 30.34Mbps

10% 31.62Mbps

30% 34.52Mbps

50% 38.49Mbps

Data rate: 54Mbps

0 500 1000 15000

5

10

15

20

25

30

35

40

Packet Size (Bytes)

Throughput(Mbps)forhigherd

atarates

54Mbps

54Mbps with 10% overheads reduced54Mbps with 30% overheads reduced54Mbps with 50% overheads reduced


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Data rate: 108Mbps

Overhead

Reduced

Throughput

0% 42.9Mbps

10% 45.5Mbps

30% 51.8Mbps

50% 60.1Mbps0 500 1000 1500

0

10

20

30

40

50

60

70

Packet Size (Bytes)

Throughput(Mbps)forhigherdatarates

108(=2*54)Mbps

108(=2*54)Mbps with 10% overheads reduced108(=2*54)Mbps with 30% overheads reduced108(=2*54)Mbps with 50% overheads reduced


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


Bandwidth Efficiency with overheads reduced


Data rate: 6Mbps

Overhead

Reduced

Bandwidth

Efficiency

0% 89.79%

10% 90.60%

30% 92.44%

50% 94.53%0 500 1000 1500

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Packet Size (Bytes)

BandwidthEfficiencyforhigherdatarates

6Mbps6Mbps with 10% overheads reduced6Mbps with 30% overheads reduced6Mbps with 50% overheads reduced


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March 2002




Data rate: 54Mbps

Overhead

Reduced

Bandwidth

Efficiency

0% 56.19%

10% 58.55%

30% 63.92%

50% 71.28%0 500 1000 1500

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Packet Size (Bytes)

BandwidthEfficiencyforhigherd

atarates

54Mbps

54Mbps with 10% overheads reduced54Mbps with 30% overheads reduced54Mbps with 50% overheads reduced


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doc.: IEEE 802.11-02/138r0

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March 2002




Data rate: 108Mbps

Overhead

Reduced

Bandwidth

Efficiency

0% 39.8%

10% 42.2%

30% 48.0%

50% 55.6%0 500 1000 1500

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Packet Size (Bytes)

BandwidthEfficiencyforhigher

datarates

108(=2*54)Mbps108(=2*54)Mbps with 10% overheads reduced108(=2*54)Mbps with 30% overheads reduced108(=2*54)Mbps with 50% overheads reduced


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doc.: IEEE 802.11-02/138r0

Submission

March 2002


Throughput Increase with overheads reduced


Doubled Rate: 12 (=2*6)Mbps

Overhead

ReducedThroughput

Increase

0% 4.65Mbps

10%

4.82Mbps30% 5.14Mbps

50% 5.52Mbps0 500 1000 1500

0

1

2

3

4

5

6

Packet Size (Bytes), Note: assume that the original is not reduced

Throughputincrease(Mbps)fordoubleddatarates

12(=2*6)Mbps12(=2*6)Mbps with 10% overheads reduced12(=2*6)Mbps with 30% overheads reduced12(=2*6)Mbps with 50% overheads reduced


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doc.: IEEE 802.11-02/138r0

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March 2002


Throughput Increase with overheads reduced


Doubled Rate:108(=2*54)Mbps

Overhead

ReducedThroughput

Increase

0% 12.59Mbps

10%

15.19Mbps30% 21.46Mbps

50% 29.73Mbps0 500 1000 15000

5

10

15

20

25

30

Packet Size (Bytes), Note: assume that the original is not reduced

Throughputincrease(Mbps)fordo

ubleddatarates

108(=2*54)Mbps

108(=2*54)Mbps with 10% overheads reduced108(=2*54)Mbps with 30% overheads reduced108(=2*54)Mbps with 50% overheads reduced


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doc.: IEEE 802.11-02/138r0

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March 2002


Conclusions

Higher Data Rates with IEEE 802.11a

compatibility should be pursued.

Effective throughput can be increased byreducing overhead.

How to achieve the Higher Data Rates and

reduce the overhead are open issues

11 02 0138-00-0wng throughput analysis for ieee 802 11a higher data rates

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