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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ Improve the latency between GTS request and usage] Date Submitted: [31 Aug, 2008] Source: [Betty Zhao, Yongjun Liu] Company [Huawei Technologies, Co., Ltd.]

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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Improve the latency between GTS request and usage] Date Submitted: [31 Aug, 2008] Source: [Betty Zhao, Yongjun Liu] Company [Huawei Technologies, Co., Ltd.] Address [Kuike Building, 9 Shangdi Xinxi Road, Haidian District, Beijing 100085] Voice: [86 10 82836033], Fax: [86 10 82836920], Email: [betty.zhao@huawei.com, yongjunliu@huawei.com] Re: [15-08-0373-01-004e-call-for-proposals] Abstract: [This document proposes a method to improve the latency between GTS request and usage by enhancing IEEE 802.15.4-2006 MAC.] Purpose: [This document is a response to Call for Proposals.] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Huawei Technologies Co., Ltd.

  2. Improve the latency between GTS request and usage Betty Zhao, Yongjun Liu Huawei Technologies Co., Ltd. Huawei Technologies Co., Ltd.

  3. GTS allocation procedure and problem • The device sends GTS request command and receives acknowledgement from the coordinator. • The device starts to track beacon for GTS descriptor from the next superframe. • The device uses GTS or request GTS again according to GTS descriptor. - Problem: if the device fails to track beacon, it must wait for at least one more beacon interval to start using GTS, which is a big latency for the data to be transmitted in GTS for lower latency. Huawei Technologies Co., Ltd.

  4. Inactive GTS GTS CAP CAP GTS GTS GTS GTS Device Fail to track beacon Can’t use this GTS Track beacon successfully Start to use GTS OR Request GTS again in the next CAP If the device fails to track the beacon, either its GTS transmission or GTS re-request will be delayed for at least a beacon interval. GTS allocation procedure and problem Huawei Technologies Co., Ltd.

  5. Proposed Solution • Precondition - According to “7.5.4.1: All devices operating on a beacon-enabled PAN shall be able to acquire beacon synchronization in order to track the beacon.”, a device known beacon synchronization can be aware of its failure of tracking the beacon. Huawei Technologies Co., Ltd.

  6. Proposed Solution Step 1: • The device sends a command (GTS information request command) to coordinator immediately after finding it failing to track the beacon (during CAP). Step 2: • On reception of GTS information request command, coordinator sends the GTS information and timestamp to the device before CFP. Step 3: • The device synchronizes with coordinator through timestamp and then uses GTS or requests GTS again according to the received GTS information. Huawei Technologies Co., Ltd.

  7. GTS CAP GTS Inactive GTS request command in 15.4 7 1 MHR fields Command Frame Identifier (TBD) GTS information request command Coordinator GTS information and timestamp GTS information request command Use GTS Device Find it failing to track beacon 7 Synchronize with coordinator 1 1 MHR fields Command Frame Identifier (0x09) GTS Characteristics Proposed Solution Huawei Technologies Co., Ltd.

  8. Proposed Solution • If “GTS information request command” is sent during CAP, - The command contains an acknowledgment request, and the PAN coordinator shall confirm its receipt by sending an acknowledgment frame. - In order for successful transmission, the device can send the command more than once until receiving the acknowledgment. • If “GTS information request command” is sent during CFP, - The PAN coordinator will check the Command Frame Identifier subfield of the received MAC command frame. - If it’s GTS information request command, the PAN coordinator will accept and process it. Huawei Technologies Co., Ltd.

  9. Thank you! Huawei Technologies Co., Ltd.

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