doc.: IEEE 802.11-15/0551r1

Submission Suhwook Kim, LG ElectronicsSlide 1

OBSS Preamble Detection Evaluation

Date: 2015-05-11

Authors:

Name Affiliations Address Phone EmailSuhwook Kim LG Electronics

19, Yangjea-daero 11gil, Seocho-gu,

Seoul 137-130, Korea

+82-2-6912-6589 suhwook.kim@lge.comWookbong Lee LG Electronics wookbong.lee@lge.comHyeyoung Choi LG Electronics hy0117.choi@lge.comJeongki Kim LG Electronics jeongki.kim@lge.comKiseon Ryu LG Electronics kiseon.ryu@lge.comHanGyu Cho LG Electronics hg.cho@lge.com

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Abstract• This submission provides evaluation of OBSS preamble

detection using PHY/MAC integrated simulator– We use preamble decoding procedure which is agreed within

integrated simulator member

– We consider frame type (Data/ACK) and link direction (DL/UL) to analyze OBSS preamble detection probability

Suhwook Kim, LG ElectronicsSlide 2

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Submissions on Preamble Detection• 14-1420r1[1], 15-367r0[2]

– Evaluate OBSS preamble detection using MAC simulator

– OBSS preamble error probability is above 80%

Suhwook Kim, LG ElectronicsSlide 3

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Preamble Error Model

Suhwook Kim, LG ElectronicsSlide 4

Signal Detect Preamble Error Detect

PreamblePPDU

• Signal Detect: At the start of preamble, – If the signal strength is above -82 dBm, receiver can start to detect the PPDU. [1]– The receiver should be in IDLE status to detect the preamble.– If the receiver is sending/receiving a frame or processing in inter-frame (SIFS), it cannot

detect any preamble even though the signal strength is above -82 dBm

• Preamble Error Detect: At the end of preamble, – In 1420r1, if minimum SINR ≤ 0 dB in preamble duration, then the preamble has errors.

Otherwise, the preamble is correct. [1]– But in this submission, we use SINR-PER curve which is addressed from Box 0 calibration

with channel model defined in SS document (980r10)– Preamble is modeled as 24 bits/symbol (BPSK 1/2) [3]

• Preamble of Data frame: L-Part (5 symbols) + VHT-Part (5 symbols) • Preamble of Control frame: L-Part (5 symbols)

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Preamble Error Model • The receiver will be locked by the first-arrived packet,

and later-arrived packets are considered as interference [3]

• If preamble passes, the receiver continues to receive the rest part of the packet [3]– If successfully decoding of a MAC frame, defer for NAV;

– Otherwise, set CCA to busy for the entire PPDU

• If preamble fails, the receiver terminates current reception [3]– The entire PPDU fails

– The receiver is unlocked again and then CCA-ED threshold is used to determine if the medium is busy

– In this submission, CCA-ED=-62 dBm

Suhwook Kim, LG ElectronicsSlide 5

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Simulation Setup [2]

Suhwook Kim, LG ElectronicsSlide 6

Simulator TypeMAC simulator (in 367r0)

PHY/MAC Integrated simulator

Tx Power (AP/STA) 20/15dBm

Antenna Gain (AP/STA) 0/-2 dBi

Traffic ModelUL only full buffer (in 367r0)

DL only, UL only, mixed DL&UL full buffer

BSS Bandwidth 80MHz

Noise Figure 0

Noise Floor -101dBm per 20MHz

Rate Control Algorithmsingle MCS chosen per link to maximize goodput

(in 367r0)Open Loop Link Adaption [4]

MSDU size (bytes) 1476

TXOP size 4 ms

Max Retx 10

Simulation Time (sec) 10

PER CurveAWGN(in 367r0)

addressed from Box 0 calibration

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Simulation Setup: modified Scenario 1 [2]

Suhwook Kim, LG ElectronicsSlide 7

• Same as 15-367r0[2]

• 3 channels– Chosen to maximize

distance between two apartments one 1 channel.

• 5 STAs per AP

• 1 antenna per AP & STA

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Throughput

Suhwook Kim, LG ElectronicsSlide 8

5% 50% 90% Mean

DL only 0.67 Mbps 10.15 Mbps 42.53 Mbps 16.08 Mbps

UL only 3.24 Mbps 7.69 Mbps 27.33 Mbps 11.80 Mbps

DL (in DL&UL) 1.08 Mbps 2.59 Mbps 4.65 Mbps 2.82 Mbps

UL (in DL&UL) 2.36 Mbps 5.74 Mbps 14.13 Mbps 7.65 Mbps

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Preamble detection

• Nt: number of total OBSS preambles which has signal strength above -82 dBm

• Nd: number of detected OBSS preambles – signal strength is over -82 dBm & arrived at IDLE status

• Ns: number of success decoded OBSS preambles

Suhwook Kim, LG ElectronicsSlide 9

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

OBSS Preamble detection

Suhwook Kim, LG ElectronicsSlide 10

May 2015

Nd / Nt Ns / Nd Ns / Nt

DL onlyDL Data 90.51% 46.17% 41.79%

UL ACK 92.50% 71.73% 66.35%

UL onlyUL Data 63.07% 63.08% 39.78%

DL ACK 65.35% 99.14% 64.79%

DL & UL

DL Data 61.09% 27.11% 16.56%

UL ACK 63.42% 51.83% 32.87%

UL Data 57.93% 50.40% 29.20%

DL ACK 63.28% 99.21% 62.78%

doc.: IEEE 802.11-15/0551r1

Submission

OBSS Preamble detection per BSS

Suhwook Kim, LG ElectronicsSlide 11

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

• Data Frame

RSSI of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 12

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

RSSI of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 13

May 2015

Preamble sent by AP

Preamble sent by STA

• ACK Frame

doc.: IEEE 802.11-15/0551r1

Submission

Effective SINR of detected OBSS preambles• Data Frame – Success

Suhwook Kim, LG ElectronicsSlide 14

May 2015

Maximum SINR of BPSK ½ in RBIR = 9.1 dB

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

Effective SINR of detected OBSS preambles• Data Frame – Failed

Suhwook Kim, LG ElectronicsSlide 15

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

• ACK Frame – Success

Effective SINR of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 16

May 2015

Maximum SINR of BPSK ½ in RBIR = 9.1 dB

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

Effective SINR of detected OBSS preambles• ACK Frame – Failed

Suhwook Kim, LG ElectronicsSlide 17

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

Simulation Setup: Scenario 3• 1 channel

– 19 APs operate in one same channel

• 30 STAs per AP

• 1 antenna per AP & STA

• ICD = 30 meter

Suhwook Kim, LG ElectronicsSlide 18

May 2015

22

11

3344

0055

66

1616

1515

99

1010

77

1414

1111

1212

1717

88

1818

1313

doc.: IEEE 802.11-15/0551r1

Submission

Throughput

Suhwook Kim, LG ElectronicsSlide 19

5% 50% 90% Mean

DL only 0.0 Mbps 0.50 Mbps 2.26 Mbps 0.85 Mbps

UL only 0.0 Mbps 0.75 Mbps 2.32 Mbps 1.02 Mbps

DL (in DL&UL) 0.0 Mbps 0.0 Mbps 0.32 Mbps 0.08 Mbps

UL (in DL&UL) 0.0 Mbps 0.73 Mbps 2.20 Mbps 0.98 Mbps

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

OBSS Preamble detection

Suhwook Kim, LG ElectronicsSlide 20

May 2015

Nd / Nt Ns / Nd Ns / Nt

DL onlyDL Data 93.22% 31.49% 29.35%

UL ACK 97.53% 52.41% 51.11%

UL onlyUL Data 73.24% 35.53% 26.02%

DL ACK 84.28% 99.05% 83.48%

DL & UL

DL Data 78.84% 15.31% 12.07%

UL ACK 83.62% 17.85% 14.92%

UL Data 72.65% 34.47% 25.04%

DL ACK 84.23% 99.01% 83.39%

doc.: IEEE 802.11-15/0551r1

Submission

OBSS Preamble detection per BSS

Suhwook Kim, LG ElectronicsSlide 21

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

• Data Frame

RSSI of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 22

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

• ACK Frame

RSSI of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 23

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

• Data Frame – Success

Effective SINR of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 24

May 2015

Maximum SINR of BPSK ½ in RBIR = 9.1 dB

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

Effective SINR of detected OBSS preambles• Data Frame – Failed

Suhwook Kim, LG ElectronicsSlide 25

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

• ACK Frame – Success

Effective SINR of detected OBSS preambles

Suhwook Kim, LG ElectronicsSlide 26

May 2015

Maximum SINR of BPSK ½ in RBIR = 9.1 dB

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

Effective SINR of detected OBSS preambles• ACK Frame – Failed

Suhwook Kim, LG ElectronicsSlide 27

May 2015

Preamble sent by AP

Preamble sent by STA

doc.: IEEE 802.11-15/0551r1

Submission

Conclusion• In this submission, we evaluate OBSS preamble detection

using PHY/MAC integrated simulator– We ran the simulations in modified residential scenario and indoor

small BSS scenario

– We observed following trends• Preamble error prob. of Data frame is HIGHER than ACK frame

• Preamble error prob. of DL Data frame is HIGHER than UL Data frame

• On the other hand, preamble error prob. of DL ACK frame is LOWER than UL ACK frame

• Preamble error prob. is generally higher in mixed DL&UL traffic model

• Preamble of DL ACK is almost decoded successfully (~99%)

Suhwook Kim, LG ElectronicsSlide 28

May 2015

doc.: IEEE 802.11-15/0551r1

Submission

Reference• [1] 11-14/1420r1 The Impact of Preamble Error on MAC

System Performance

• [2] 11-15/0367r0 OBSS Preamble Detection

• [3] 11-14/1523r5 Offline Discussion Minutes of SLS Calibration

• [4] 11-14/620r0 link adaptation for PHY SLS calibration

Suhwook Kim, LG ElectronicsSlide 29

May 2015