Doc.: IEEE 802.11-10/1244r1 Submission Nov.2010 Sun Bo, ZTE CorpSlide 1 Authors: Transmission...

transcript

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

Sun Bo, ZTE CorpSlide 1

Authors:

Transmission Mechanism in MU-MIMO

Date: 2010-11-10

Name Affiliations Address Phone Email

Sun Bo ZTE Corporation No.10 Sth Tangyan Rd. Xi’an, China

86 29 88723975 Sun.Bo1@zte.com.cn

Tian Kaibo ZTE Corporation No.10 Sth Tangyan Rd. Xi’an, China

86 29 88723973 tian.kaibo@zte.com.cn

Lv Kaiying ZTE Corporation No.10 Sth Tangyan Rd. Xi’an, China

86 29 88724130 lv.kaiying@zte.com.cn

Zhendong Luo China Academy of Telecommunication Research (CATR)

No.52 Huayuan Bei Rd. Beijing, China

86 10 62300171 luozhendong@catr.cn

Siyang Liu China Academy of Telecommunication Research (CATR)

No.52 Huayuan Bei Rd. Beijing, China

86 10 62300175 liusiyang@catr.cn

Liang Peng China Telecom No. 118, Xizhimengnei St., Beijing, China

86 10 58552342 liangpeng@ctbri.com.cn

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

Abstract

A detailed transmission mechanism for MU-MIMO are proposed in this contribution, including protective mechanism with CTS-to-Self and scheduled multiple RTS/CTS frame changes, MU-MIMO data transmission, scheduled ACK and exception handling.

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

Background

• Current data transmission mechanism was designed for SU-MIMO only– Tx STA sends RTS addressing one Rx STA with one RA field.

– Rx STA addressed by the RA field responds with CTS.

– Not all recipients’ neighbors can be protected.

• Challenges to MU-MIMO data transmission:– Define multiple recipients RTS/CTS protective mechanism.

– Define MU-MIMO data selection method.

– Define multiple recipients ACK scheduling.

– Define retransmission rules.

– Be compatible with legacy devices.

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

MU-MIMO Transmission Mechanism

• A short PPDU, e.g. CTS-to-Self is used to start MU-MIMO transmission and reserve the MAX transmission duration, including all RTS/CTSs, MU-MIMO data frames, scheduled ACKs and all xIFSs.

• Multiple RTS/CTS frame exchanges are used to reserve bandwidth for multiple recipients

• The RTS/CTSs for primary STAs will be arranged first.

• If no CTS is correctly received from any primary STA, the current MU-MIMO transmission is failed. If the remaining time within the TXOP duration is sufficient to complete an MU-MIMO transmission, AP may initiate a new transmission or retry the previous MU-MIMO transmission. AP may terminate the TXOP with a CF-END.

• Otherwise, if a CTS is not correctly received, AP should issue the next RTS, until RTS/CTS exchanges for all rest scheduled recipients are issued.

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

MU-MIMO Transmission Mechanism (cont.)

• MU-MIMO data streams are carried in a MU-MIMO data frame based on above reservation.

• Only data with successfully received CTS will be carried in the MU-MIMO data frame;

• Planned data without a successfully received CTS will be removed from the MU-MIMO data frame.

• Scheduled ACKs are used for each recipient to acknowledge the receiving of data carried in MU-MIMO data frame.

• A CF-END may be used to terminate a MU-MIMO transmission if the transmission is terminated before the duration reserved by CTS-to-Self.

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

MU-MIMO Transmission Mechanism Analysis

CTS-to-Self RTS

Multi-use-dataSIFS

• A CTS-to-Self is used to reserve a long duration allowing MU-MIMO transmission through “duration” field

• AP checks scheduled recipient one by one by RTS/CTS exchanges

• The RTS(s) for primary STA(s) should be arranged firstly.

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

MU-MIMO Transmission Mechanism Analysis (cont.)

• If AP does not detect a valid CTS frame within one SIFS period plus a delta time (TBD) following the RTS transmission, AP shall initiate the next RTS/CTS frame exchange, or start MU-MIMO data frame transmission.

• The data for a scheduled recipient with unsuccessful RTS/CTS frame exchange will be removed from the transmitted MU-MIMO data frame.

CTS-to-Self RTSRTS

MU-MIMO dataSIFS

CTS is missed

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

MU-MIMO data

• The ACK(s) is (are) scheduled based on the stream information indicated in the Nsts field of MU-MIMO data frame.

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

• If one ACK is missed, the other STA(s) will send ACK at the scheduled time shown as below.

MU-MMO data

ACK is missed

retransmission

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

• Only when any primary STA failed to receive MU-MIMO data, the AP will initiate retransmission.

• The retransmission could be:

• retransmitted MU-MIMO data frame which includes at least the data for a primary STA failed in previous MU-MIMO transmission, and the data for other STA(s) failed in previous MU-MIMO transmission, or

• retransmitted SU-MIMO data frame which includes the data for a primary STA failed in previous MU-MIMO transmission, or

• retransmitted MU-MIMO data frame which includes at least the data for a primary STA failed in previous MU-MIMO transmission, and the data for other STA(s) failed in previous MU-MIMO transmission, and new data for other STA(s) succeeded in previous MU-MIMO transmission

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

Summary

• The proposed MU-MIMO transmission mechanism provides following advantages:

– Avoiding hidden node problems in BSS and OBSS

– Compatibility with legacy devices

– Reuse of legacy RTS/CTS frame exchanges

– Avoiding unexpected confliction during the gap when a CTS is missed

– Efficient MU-MIMO transmission

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

References

[1] Yun.Joo.Kim , et. al., “considerations-on-mu-mimo-protection-in-11ac” IEEE 802.11-10/335r01.

[2] Allan Zhu, et. al, “txop-sharing-for-dl-mu-mimo-support” IEEE 802.11-10/1123r00

[3] Tian Kaibo, et. al, “Multiple CTSs in MU-MIMO transmission” IEEE 802.11-10/1067r00

doc.: IEEE 802.11-10/1244r1

Submission

Nov.2010

Thank you!

Sun Bo, ZTE Corp

Doc.: IEEE 802.11-10/1244r1 Submission Nov.2010 Sun Bo, ZTE CorpSlide 1 Authors: Transmission...

Documents