Date: 2013-04-24

1. Backward Compatibility Feature for 802.11aj Date: 2013-04-24 Presenter: Xiaoming Peng

2. Author List Xiaoming Peng

3. Abstract • This document is to describe the understanding of the backward compatibility feature for 802.11aj for the 60GHz frequency band • To respond to 11-13/0292r0 – Backward compatibility of 11aj with 11ad • This contribution has been discussed in CWPAN group Xiaoming Peng

4. Background • IEEE 802.11aj PAR specified backward compatibility to IEEE 802.11ad. • Definition of backward compatibility is crucial to 802.11aj in deciding the level of support required. • There is no consensus yet on the meaning of backward compatibility. • In this presentation, we present a definition based on broad principles of fairness and efficiency. • Seek to achieve a broad consensus within 802.11aj Task Group if possible or identified the points of contention for future resolution. Xiaoming Peng

5. Backward Compatibility Feature 802.11aj MAC (amendment to 802.11-2012 + amendment to 802.11ad) 802.11aj STA 802.11aj PHY in 45GHz 802.11ad PHY 60GHz 802.11aj PCP 802.11ad STA 802.11aj PHY in 60GHz Scenario: 802.11aj (60GHz) 802.11aj Architecture • Only when 802.11aj device operates over Chinese 60GHz channel, it is required to keep the backward compatibility to 802.11ad Xiaoming Peng

6. Comments on 11-13/0292r0 • 11-13/0292r0 highlighted the following • 11n does not have modes: 11n has PHY formats (legacy, HT-MM, HT-GF) with associated usage rules to ensure backwards compatibility • Greenfield “mode” does NOT imply that there is no backward compatibility • Greenfield allows data transmissions in a BSS to be restricted to a given mode (e.g., HT), but backward compatibility still exists • Use of HT-GF format is subject to an array of restrictions to minimize backwards compatibility issues. E.g., review the HT Protection, Nongreenfield HT STAs Present and OBSS Non-HT STAs Present fields in the HT Operation element, and associated normative text • It is agreeable to remove the “Exclusive Mode” described in 11-13-1750r0 in the following slide Xiaoming Peng

7. Compatibility Modes(IEEE 802.11 Precedent) • IEEE 802.11n supports three compatibility modes to a/b/g • Legacy Mode • Mixed Mode • Greenfield Mode • We propose 11aj to support two correspondingly compatibility modes to 11ad • Legacy Model (Large Band Only Mode) • 802.11aj operate as 802.11ad device (Outside China). • Mixed Mode • 802.11aj can support both the 802.11ad STAs and 802.11aj STAs. Xiaoming Peng

8. Legacy Mode • 802.11aj devices will operate according to 802.11ad channels and protocols. • No new protocols required. • Used primarily when 802.11aj devices are operating outside of China. Xiaoming Peng

9. Mixed Mode • 802.11aj BSS can support the operation of both the 11ad devices and 11aj devices. • 802.11ad STAs able to join the network and perform data exchange with AP/PCP and other STAs in 802.11aj BSS • 802.11aj STAs able to join the network and perform data exchange with other 802.11aj STAs; • Formation of new network • 802.11ad AP/PCPs can start a new network if channel is available. Xiaoming Peng

10. Principles in Determining Channel Access • Principle: Equal priority between IEEE 802.11ad and IEEE 802.11aj STA. • Application of the principles to the different operating scenarios • Formation of new network • New STAs joining existing network Xiaoming Peng

11. Thank YOU Xiaoming Peng