Submission doc.: IEEE 802.11-14/1179r0 September 2014 Gwangzeen Ko, ETRISlide 1 Considerations for Partial Band Interference between WLAN Systems Date:

Submission

doc.: IEEE 802.11-14/1179r0September 2014

Gwangzeen Ko, ETRISlide 1

Considerations for Partial Band Interference between WLAN Systems

Date: 2014-09-10

Name Affiliations Address Phone email

Gwangzeen Ko ETRI Korea +82-42-860-

4862 [email protected]

Hyunduk Kang ETRI Korea +82-42-860-


Igor Kim ETRI Korea +82-42-860-


Jin-Hyung Oh ETRI Korea +82-42-860-


Myung-Sun Song ETRI Korea +82-42-860-


Jae-Ick Choi ETRI Korea +82-42-860-


Authors:

Submission



Abstract

• In the OBSS area, WLAN throughput decrease depending on number of overlapped BSS due to the time sharing policy between WLAN systems.

• There are two types of interferers between overlapped BSSs. One is full band interference from neighbor BSSs. Another is partial band interference.

• In this presentation, we will discuss both partial band interference problems and possible solution.

Submission



Introduction

• Full band interference• When two or more devices’ operation band are fully

overlapped. This type of interference is called by Full band interference each others

• Both center frequency and bandwidth are exactly same

• Partial band interference• When two or more devices’ operation band are partially

overlapped. This type of interference is called by Partial band interference each others

• Both center frequency and bandwidth are NOT exactly same

Submission



Introduction

• Full band vs Partial band interference example in 2.4GHz band

CH#1

CH#3

CH#2

AP

AP

AP

STA

STA

CH.1 CH.3

10MHz Overlap

CH.1 CH.2

15MHz Overlap

Partial Bandwidth Overlap

Partial Bandwidth Overlap

STA

AP

CH.1

20MHz Overlap

Full Bandwidth Overlap

CH#1

2400MHz 2483.5MHz5MHz

20MHz

CH.1 CH.2 CH.3 CH.4 CH.5 CH.6 CH.7 CH.8 CH.9 CH.10CH.11CH.12 CH.13

Submission

doc.: IEEE 802.11-14/1179r0


September 2014

Bandwidth Overlap Problems

• Because of time sharing policy for coexistence between BSSs called CSMA/CA, bandwidth overlap yields performance degradation.

• This performance degradation is an expected problem since WLAN was born.

• However, this simple coexistence protocol is a good solution for bandwidth overlap between BSSs.

• Solution of this problem will be supported by Functional Requirement of IEEE 802.11ax(TGax R7)[1]• The 802.11ax amendment shall provide a mechanism to facilitate frequency reuse and

manage interference between neighboring overlapping BSS (OBSS) in dense deployment scenarios with a high density of STAs per BSS or a high density of both STAs and BSSs

Submission

doc.: IEEE 802.11-14/1179r0


September 2014

Difference between Full and Partial Bandwidth Overlap

• In full bandwidth overlap case, time division solution is available.

• Whereas, in partial bandwidth overlap case, there are some clean frequency bands additionally.

• These clean parts of bandwidth are a hiding resource of current WLAN networks.

• So, if we can use those clean part of bandwidth, WLAN performance can be improved. CH.1 CH.2

15MHz Overlap

CH.1 CH.3

10MHz Overlap

Clean Bandwidth = No WLAN interference

Submission

doc.: IEEE 802.11-14/1179r0


September 2014

Characteristics of Fully and Partially Overlapped Bandwidth

• Fully overlapped bandwidth• Possible : both physical layer detection and NAV information

• Partially overlapped bandwidth• Possible : physical layer detection and expected low signal

strength• Hard to decode NAV information

• To detect partial overlap bandwidth accurately, we need modification of existing CCA procedure based on signal characteristics of partial overlap cases.

Submission

doc.: IEEE 802.11-14/1179r0

Gwangzeen Ko, ETRI

What about 5GHz?

• Similar situation in 5GHz band!

Slide 8

September 2014

20MHz

80MHz

40MHz

AP

AP

AP

STA

STA

20M BW 40M BW

20MHz Overlap

STA20M BW 80M BW

20MHz Overlap

Submission

doc.: IEEE 802.11-14/1179r0

Gwangzeen Ko, ETRI

Possible Solution for Bandwidth Overlap Problem

Slide 9

September 2014

• Non Overlap approach(Level 1)• Higher Layer or User Management

• Government Guide Line for band selection• Powerful for 2.4GHz and enterprise devices

• Providing intelligence initial bandwidth selection and updating mechanism• How often?• Automatically or User setting?

• Overlap approach(Level 2)• Full band overlap case

• Time Division Access• Partial band overlap case

• Time and Frequency Division Access OFDMA

Submission

doc.: IEEE 802.11-14/1179r0

Gwangzeen Ko, ETRI

Summary

• IEEE 802.11ax will support various performance enhancement techniques

• There are unused resource in the frequency domain which is some clean bandwidth under partially overlapped OBSS situation

• Usage of these unused bands provides higher performance in IEEE 802.11ax standard

Slide 10

September 2014

Submission



References

[1]Lei Wang et. al.,11-14-0567-07-00ax-proposed-tgax-functional-requirements

Documents

Submission doc.: IEEE 802.11-14/1179r0 September 2014 Gwangzeen Ko, ETRISlide 1 Considerations for Partial Band Interference between WLAN Systems Date: