Submission doc.: IEEE 11-14/0868r0 July 2014 Johan Söder, Ericsson ABSlide 1 UL & DL DSC and TPC...
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Transcript of Submission doc.: IEEE 11-14/0868r0 July 2014 Johan Söder, Ericsson ABSlide 1 UL & DL DSC and TPC...
Submission
doc.: IEEE 11-14/0868r0July 2014
Johan Söder, Ericsson ABSlide 1
UL & DL DSC and TPC MAC simulationsDate: 2014-07-14
Name Affiliations Address Phone email Johan Söder Ericsson AB Färögatan 6, Stockholm,
Sweden +46 722449170 johan.soder
@ericsson.com Filip Mestanov Ericsson AB filip.mestanov
@ericsson.com Leif Wilhelmsson Ericsson AB leif.r.wilhelmsson
@ericsson.com Hakan Persson Ericsson AB hakan.z.persson
@ericsson.com Kåre Agardh Sony Mobile kare.agardh
@sonymobile.com
Bill Carney Sony USTSO William.Carney @am.sony.com
Kazuyuki Sakoda Sony ITDD KazuyukiA.Sakoda @jp.sony.com
Authors:
Submission
doc.: IEEE 11-14/0868r0July 2014
Johan Söder, Ericsson ABSlide 2
Abstract
In this presentation we share system simulations results obtained from the evaluation of a Dynamic Sensitivity
Control (DSC) mechanism (for both UL and DL) as well as results evaluating the potential of Transmission Power
Control (TPC)
Submission
doc.: IEEE 11-14/0868r0July 2014
Johan Söder, Ericsson ABSlide 3
Context
• DSC [1], [2] has been shown to provide performance improvements in UL
• However, the majority of the traffic is still in DL direction; hence DL optimization techniques need also be considered
• Transmit Power Control (TPC) is another proposed feature that shows promising results
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
Simulation scenario 2:Enterprise
Slide 4
July 2014
› “Enterprise Scenario” as defined in [3]• 8 offices, 64 cubicles per office, 2 STAs
per cubicle • (8 x 64 x 2) / 32 = 32 STA/AP
• 4 x 20MHz channels (8 APs on the same channel)
• 32 x 8 = 256 STAs on the same channel
• COST231 propagation model› Web-browsing and local file transfer
AP<->STA
› No P2P links included
BSS9-12 BSS13-16 BSS24-28 BSS29-32
BSS1-4 BSS5-8 BSS17-19 BSS20-23
20 m
20 m
STA1
STA2
STA3
2 m
2 m
STA4
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
Simulation assumptions
• MAC layer simulator
• 802.11n
• Tx Power AP = 20dBm
• Tx Power STA = 20dBm
• Antennas AP: 2Tx, 2Rx
• Antennas STA: 2Tx, 2Rx
• Reference CCAT = -82dBm
Slide 5
July 2014
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
Traffic assumptions
• Files arrive independently in the buffers of the STAs(UL) and the APs (DL, files labelled with a receiver STA)
• Arrival process is a Poisson process
• Arrival intensity of DL and UL files has ratio 80/20
• Different system loads are modelled by varying arrival intensity, the file size is kept constant
• Sample file size is 1MB
Slide 6
July 2014
Submission
doc.: IEEE 11-14/0868r0
Definitions
• Packet throughput = packet size / packet delay
• Packet delay = time from packet arrives in buffer until time the last ACK is received
• User throughput = average of packet throughputs for a user
• Served traffic = Sum of all successfully received packets / simulation time
• Served traffic ~ system arrival intensity * packet size
Slide 7 Johan Söder, Ericsson AB
July 2014
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
UL:Dynamic sensitivity control
• The DSC mechanism evaluated in this work consists of each STA autonomously setting their respective Rx sensitivity threshold as:
RxSensT= RSSI – MAR• RSSI is received signal strength from AP
• MAR is a parameter that controls how aggressive the algorithm is
• CCA threshold (CCAT) is set as:• CCAT = max(CCAT_default, RxSensT)
• In these evaluations MAR = 15dB
Slide 8
July 2014
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
• The AP per-link CCAT evaluated in this work consists of the AP setting an individual CCAT for each STA:
CCATA = max(CCATDefault, RSSIA – MARA )
CCATB = max(CCATDefault, RSSIB – MARB )
• RSSIA, B are the received signal strength for
STAs A and B respectively
• MARA, B are parameters that controls
how aggressive the algorithm is
• In these evaluations MARA = MARA = 15dB
DL:AP per-link CCAT adaptation
July 2014
Slide 9
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
0 5 10 15 20 250
20
40
60
80
100
120
140
Served traffic per AP (DL+UL) [Mbps]
Fif
th P
erc
en
tile
Us
er
Th
rou
gh
pu
t [M
bp
s]
Ref [DL]Ref [UL]DSC [DL]DSC [UL]DSC+AP Per-Link CCAT [DL]DSC+AP Per-Link CCAT [UL]
0 5 10 15 20 250
20
40
60
80
100
120
140
Served traffic per AP (DL+UL) [Mbps]
Fif
th P
erc
en
tile
Us
er
Th
rou
gh
pu
t [M
bp
s]
Ref
DSCDSC+AP Per-Link CCAT [DL]
Enterprise scenario:Sensitivity control
Some gains from DSC in user throughput for all links (left figure), mainly impacts the UL (right figure)
DSC in combination with AP per-link CCAT shows great potential, improves both DL & UL user throughput
July 2014
Slide 10
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
0 5 10 15 20 250
10
20
30
40
50
60
Served traffic per AP (DL+UL) [Mbps]
DL
SIN
R (
Me
an
an
d 5
th p
erc
) [d
B]
RefDSCDSC+AP Per-Link CCAT [DL]
2 4 6 8 10 12 140
1
2
3
4
5
6x 10
-5
Served traffic per AP (DL+UL) [Mbps]
De
lay
[s
]
Queuing
Contention
Collision
SINR and Delay time
DL SINR is reduced but still very high
Queuing time is reduced
Slide 11
July 2014
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
Enterprise scenario:Combined results
Capacity for 20Mbps user throughput requirement (95%)
Slide 12
July 2014
Ref UL DSC DL+UL DSC 0
5
10
15
20
25
System capacity [Mbps/AP]
30%
90%
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
Transmit power control (TPC)
• DL power reduction: DL power is set to reach a target SNR at the potential STA location with highest pathloss• Time-varying DL TPC where the associated STA with highest
pathloss is used to set the power could also be investigated.
• Link-dependent DL TPC could also be investigated
• UL power control: UL power is set to reach a target SNR at the AP
• Target SNR DL & UL is 30dB
Slide 13
July 2014
Submission
doc.: IEEE 11-14/0868r0
Johan Söder, Ericsson AB
0 5 10 15 20 250
20
40
60
80
100
120
140
Served traffic per AP [Mbps]
Fif
th P
erc
en
tile
Ob
jec
t D
ata
Ra
te [
Mb
ps
]
RefDL pwr, 30dBDL pwr+UL PC, 30dB
Enterprise scenario:Power control
Ref: DL: 20dBm, UL: 20dBm
DL Pwr: Adjust AP DL power to get target SNR at STA with highest pathloss
UL PC: Adjust STA UL power to get target SNR at AP
July 2014
Slide 14
Ref DL TPC DL+UL TPC05
10152025
System capacity [Mbps/AP]
30%77%
Submission
doc.: IEEE 11-14/0868r0July 2014
Johan Söder, Ericsson ABSlide 15
Conclusion
• DSC improves performance in UL
• Setting the CCAT at AP (for transmission in DL) gives improvements in DL
• Combining DSC and DL CCAT setting gives a well balanced UL & DL performance.
• TPC gives system capacity gains
Submission
doc.: IEEE 11-14/0868r0July 2014
Johan Söder, Ericsson ABSlide 16
References
[1] 11-14-0779-00-00ax-dsc-practical-usage
[2] 11-14-0523-00-00ax-mac-simulation-results-for-dsc-and-tpc
[3] 11-14-0621-04-00ax-simulation-scenarios