Submission

doc.: IEEE 802.11-15/0097r0

Slide 1

Performance Analysis of Frequency Selective Scheduling

Date: 2015-01-12Authors:

Ningbo Zhang, BUPT

January 2015

Name Affiliations Address Phone Email

Ningbo Zhang

Beijing University of

Posts and Telecommunicati

ons

Beijing, China nbzhang@bupt.edu.cn

Guixia Kang

Beijing University of

Posts and Telecommunicati

ons

Beijing, China gxkang@bupt.edu.cn

Submission

doc.: IEEE 802.11-15/0097r0

Abstract

• Background• Evaluation methodology• Simulation Parameters• Performance comparison • Conclusions

Slide 2 Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

Background

• OFDMA is a positional technology to increase the spectral efficiency in 802.11ax

• Frequency selective scheduling is allowed in OFDMA systems

• The gain of frequency selective scheduling depends on: – Scheduling algorithm– Number of users– Radio environment – Channel estimation – Channel state information(CSI) reporting delay

• In this contribution, we study the performance of frequency selective in fading channels

Slide 3 Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

Evaluation methodology

• Scheduling algorithms• Single user

• Algorithm 1: one user transmits data packet on the fixed subband• Algorithm 2: one user transmits data packet on a random subband • Algorithm 3: Frequency selective scheduling, one user transmits data

packet on the best subband

• Multiple Users• Algorithm 1: multiple users transmits data packets on the fixed subbands• Algorithm 2: multiple users transmits data packets on a random subbands • Algorithm 3: Frequency selective scheduling, users are allocated to

suitable subbands to transmit data packets

Slide 4 Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

Simulation Parameters

Slide 5

• Bandwidth: 20MHz• Number of STA: 4• MCS selection: MCS to achieve highest throughput• Channel estimation: MMSE• CSI feedback: Perfect CSI feedback• Channel model: EPA

Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

Performance comparison for single user

Slide 6

0 2 4 6 8 10 12 14 16 18 201

2

3

4

5

6

7

8

9x 10

6

SNR(dB)

Thr

ough

put(

bps)

Algorithm1: Fixed Subband Algorithm2: Random Subband Algorithm3: Frequency Selective Subband

• The performance of random selective subband is similar with fixed subband.

• Frequency selective subband shows large performance gains compared with random subband and fixed subband.

Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

Performance comparison for multiple users

Slide 7

• The performance of frequency selective subband outperforms fixed subband and random subband

• The throughput gain of multiple user is smaller than that of single user.

0 2 4 6 8 10 12 14 16 18 200

0.5

1

1.5

2

2.5

3

3.5

4x 10

7

SNR(dB)

Thr

ough

put(

bps)

Algorithm 1: Fixed SubbandAlgorithm 2: Random SubbandAlgorithm 3: Frequency Selective Subband

Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

Conclusions

• The performance of random selective subband is similar to the performance of fixed subband.

• Frequency-selective scheduling can provide gain for both single user and multiple user cases.

• The performance gain of single user is larger than that of multiple users.

• The inaccurate CSI feedback may lead to scheduling performance loss, but need further study.

Slide 8 Ningbo Zhang, BUPT

January 2015

Submission

doc.: IEEE 802.11-15/0097r0

References

[1]11-14/0858r0, “Analysis on Multiplexing Schemes exploiting frequency selectivity in WLAN Systems”

[2] 11-14/1227r3, “OFDMA Performance Analysis”

[3] “LTE Frequency Selective Scheduling Performance and Improvements Assessed by Measurements”, IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011.

Slide 9 Ningbo Zhang, BUPT

January 2015