Enhanced Beam Tracking Against Blockage: Resolution to CID 145 Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Enhanced Beam Tracking Against Blockage: Resolution to CID 145 Date: 2014-9-5 Bo Gao, Tsinghua University John Doe, Some Company

Bo Gao, Tsinghua University September 2014 Abstract This is a submission for comment resolution on D0.01 for comment #145. This submission provides an enhance beam tracking mechanism against human blockage. The mechanism can reduce the outage probability, and obtain a competitive throughput. Bo Gao, Tsinghua University

Bo Gao, Tsinghua University September 2014 Comment #145 According to the usage model of 11aj, the mobile device (e.g. smart phones) application is considered. In the case of device movement, the blockage probability of the transmission link is increasing significantly. Thus, the problem of unexpected blockage should be resolved. Resolution： This submission provides an enhance beam tracking mechanism against human blockage, by tracking and switching an alternative beam pair. Bo Gao, Tsinghua University

Bo Gao, Tsinghua University Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Human Blockage Owing to the huge path loss, the 60-GHz communications have to utilize the high-antenna-gain directional transmission. However the directional communications limit the multipath diversity and make them vulnerable to human blockage. Human blockage poses approximately 20 dB attenuation. These attenuation can prevent the 60-GHz WLAN system from supporting multi-gigabit throughput and even break the communication link. Based on the usage model of 11aj, the mobile device (e.g. smart phones) application is considered. In the case of device movement, the blockage probability of the transmission link is increasing significantly. Thus, the problem of unexpected blockage should be resolved Bo Gao, Tsinghua University John Doe, Some Company

Bo Gao, Tsinghua University Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Blockage Model The shadowing induced by human blockage is described by a piecewise linear model, based on study of Peter et al [3]. The attenuation in dB is modeled by a period with linear increase, a period with a constant level and a period with linear reduction. The duration of a decay of attenuation, i.e., tdecay, is about 100 ms, which is enough for a 60-GHz transceiver to detect the blockage and switch to an alternative link. Bo Gao, Tsinghua University John Doe, Some Company

Beam Tracking Against Blockage (1) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Beam Tracking Against Blockage (1) In DMG STA Capability Information field, one reserved bit (i.e., B62: Enhanced Beam Tracking Supported) is used to illustrate the support for enhanced beam tracking. Bo Gao, Tsinghua University John Doe, Some Company

Beam Tracking Against Blockage (2) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Beam Tracking Against Blockage (2) Enhanced Beam Tracking IE is added to 11aj. Element ID is equal to the value for the DMG BSS Parameter; Length is setting to 4; Backup AWV Setting is to update the alternative AWV of peer. The default of alternative AWV is omni-directional antenna: if Backup AWV Setting is 00, it indicates that the peer does not update the alternative AWV ; if Backup AWV Setting is 01, it indicates that the peer updates the alternative AWV according to the AWV specified by Peer Tx_Sector ID and Peer Tx_Antenna_ID ; if Backup AWV Setting is 10, it indicates that the current received AWV of peer is used to update the alternative AWV ; if Backup AWV Setting is 11, it indicates that the lasted transmitted AWV of peer is used to update the alternative AWV. Bo Gao, Tsinghua University John Doe, Some Company

Beam Tracking Against Blockage (3) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Beam Tracking Against Blockage (3) Enhanced Beam Tracking IE is added to 11aj. Peer Tx_Sector ID indicates the Sector ID of alternative Tx AWV of peer. Peer Tx_Antenna ID indicates the Antenna ID of alternative Tx AWV of peer. If E-BT-R Request is 1, it indicates that the peer is requested to enable the enhanced beam tracking for RX; otherwise, it is set to 0. If E-BR-R OK is 1, it indicates that the device has been enabled the enhanced beam tracking for RX ; otherwise, it is set to 0. If E-BT-T Request is 1 , it indicates that the peer is requested to enable the enhanced beam tracking for TX ; otherwise, it is set to 0. If E-BR-T OK is 1, it indicates that the device has been enabled the enhanced beam tracking for TX ; otherwise, it is set to 0. If Switch to Backup AWV is 1, it indicate that the reception/transmission of the next packet is starting to use the alternative AWVs; otherwise, it is set to 0. Bo Gao, Tsinghua University John Doe, Some Company

Beam Tracking Against Blockage (4) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Beam Tracking Against Blockage (4) In order to maintain multi-gigabit transmission against blockage, an appended field is added to the end of the beam refinement (BRP) packet. Enhanced beam refinement packet is proposed in Fig. 1. The appended STF and CE field shall be transmitted and received by the alternative beam pair. The STF field is to accomplish packet detection, AGC adjustment, synchronization to establish communication. The CE field is to achieve the SNR estimation about alternative beam pair. While obtaining the higher SNR than the current transmission link, the transmitted and received beams switch to alternative pair immediately. Fig.1. Enhanced beam refinement packet Bo Gao, Tsinghua University John Doe, Some Company

Enhanced Beam Tracking Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Enhanced Beam Tracking The enhanced beam tracking for RX is illustrated as follows. Bo Gao, Tsinghua University John Doe, Some Company

Enhanced Beam Tracking Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Enhanced Beam Tracking The enhanced beam tracking for TX is illustrated as follows. Bo Gao, Tsinghua University John Doe, Some Company

Performance Evaluation (1) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Performance Evaluation (1) The scheme in comparison is the single-link beam tracking scheme in IEEE 802.11ad. In the simulation, we consider the indoor scenario where the room size is 8 m × 8 m. DEV-a and DEV-b are randomly placed in the room. Received power trajectory: The results reveal that the received signal obtained by the proposed scheme can serve the upper-bound of the performance. When the human blockage is finished, the proposed scheme can switch to the optimal link in time. Since not probes the blocked link, the single-link beam tracking scheme can only maintain the current link when received power drops severally. Bo Gao, Tsinghua University John Doe, Some Company

Performance Evaluation (2) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Performance Evaluation (2) The scheme in comparison is the single-link beam tracking scheme in IEEE 802.11ad. In the simulation, we consider the indoor scenario where the room size is 8 m × 8 m. DEV-a and DEV-b are randomly placed in the room. Outage Probability: Compared with the single-link beam tracking scheme, the proposed scheme has a prominent improvement. It is due to the fact that the proposed scheme can switch to alternative link without the requirement of additional beam training. The scheme can thus effectively reduce retransmission of dropped packet. Bo Gao, Tsinghua University John Doe, Some Company

Performance Evaluation (3) Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2014 Performance Evaluation (3) The scheme in comparison is the single-link beam tracking scheme in IEEE 802.11ad. In the simulation, we consider the indoor scenario where the room size is 8 m × 8 m. DEV-a and DEV-b are randomly placed in the room. Throughput: If the human blockage probability is zero, the throughput of the proposed scheme is slightly less than that of the single-link beam tracking scheme. It is because that the proposed scheme needs the aided pilots to probe and maintain the alternative link. Once the blockage happens, the throughput of the single-link beam tracking scheme is down sharply. In contrast, the proposed scheme keeps a high-level throughput. Bo Gao, Tsinghua University John Doe, Some Company

Bo Gao, Tsinghua University September 2014 Summary This submission provides an enhanced beam tracking mechanism against human blockage for comment #145 on the comment resolution for D0.01. Modifications to 802.11aj MAC: In DMG STA Capability Information field, one reserved bit (i.e., B62: Enhanced Beam Tracking Supported) is used to illustrate the support for enhanced beam tracking. Enhanced Beam Tracking IE is added to 11aj. Modifications to 802.11aj PHY packet: The appended STF and CE field is added in the end of BRP packet, which is transmitted once conducting enhanced beam tracking. Bo Gao, Tsinghua University

Bo Gao, Tsinghua University September 2014 Question-A Qs: The proposal is mandatory or optional? Answer: Optional. One bit in DMG STA Capability Information field is used to indicate whether the device supports the enhanced beam tracking scheme. Bo Gao, Tsinghua University

Bo Gao, Tsinghua University September 2014 Reference IEEE P802.11ad, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications – Amendment 3: Enhancements for Very High Throughput in the 60 GHz band,” December 2012. IEEE P802.11aj, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications Amendment X: Enhancements for Very High Throughput to Support Chinese Millimeter Wave Frequency Bands(60GHz) ,” January 2014 M. Peter, et al., “Analyzing human body shadowing at 60 GHz: Systematic wideband MIMO measurements and modeling approaches,” in Proc. 2012 IEEE EUCAP, pp. 468–472. K. Huang, Z. Wang, “Millimeter wave communication systems,” John Wiley & Sons Ltd., 2011 Bo Gao, Tsinghua University