1. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 1 User Scenario example; Sensor Overlay Network Notice: This document has been prepared to assist IEEE 802.11. 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 grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Date: 2005-03-15 Authors:

2. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 2 Abstract Factory automation management service providers, such as a building facility management company, have been studying how to use WLAN infrastructure to the system which monitors environmental information such as temperature, humidity, lightness, frost, etc., in Japan. In such systems, it is indispensable to keep the data reliability from sensor nodes to a monitoring server which is connected to a fixed network. However, sensor nodes have limited resources (CPU, memory, battery power, etc.), they have limited wireless communication range. As a result, sensor nodes can not directly communicate to an AP which is located in the edge of the fixed network. One solution is to use WLAN as a bridging network between a sensor network and a fixed network. We call this hybrid wireless network as “a sensor overlay network”. We would like to add this user model to a candidate of user scenarios in TGv. We show a brief overview of the sensor overlay network in this presentation.

3. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 3 Sensor overlay network Definition: –Sensor overlay network consists of a wireless LAN constructed by a few APs and sensor networks. Objectives: –Provide reliable wireless access network Data collection (Data are sent from sensors to a monitoring server) Remote sensor control (Control messages are pushed to sensors from a monitoring server) Requirements: –Enable a sensor server to select an AP according to the network condition based on 802.11k and 802.11v. Fixed LAN WLAN Sensor network Sensor server Gateway (AP) Sensor node A monitoring server

4. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 4 Flexible gateway selection method for reliable sensor overlay networks Sensor Network Sensor server Fixed LAN WLAN Communication obstacle Gateway (AP) Sensor node (2) (3) Context transfer Including key management information Data (1) (1) A sensor server “A” detects a failure or quality degradation to AP “X”. (2) The sensor server “A” tries to look for an alternative gateway. (3) If it does not find, it notifies sensor nodes to select another sensor server. A X A monitoring server Y B

5. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 5 Sensor overlay network (ZigBee NWK) 802.11 Resource and fault management IP 802.15.4 Application SN (Sensor Network) WLAN 802.11k/802.11vZigBee LQI, etc. LQI (Link Quality Identification)

6. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 6 Basic functions of sensor overlay networks Detect link failure/degradation Find and create alternative links –in WLAN (by sensor servers collaborating with APs) –in SN (by sensors collaborating with sinks) Reconstruct routes –on WLAN –on SN (out of scope in terms of 11v)

7. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 7 Requirements for APs and sensor servers Detect link failure/degradation –Link quality (bit/frame error rate, etc.) –Traffic load (avg., max., current, etc.) –Congestion Find and create alternative WLAN links –Channel availability –Topology Available APs (in the infrastructure mode) Available STAs (in the ad-hoc mode) –(and 3 parameters listed above)

8. doc.: IEEE 802.11-05/0048r0 Submission March 2005 Tatsuji Munaka, Mitsubishi Electric Corp.Slide 8 References