Source: [Chunhui Zhu] Company [Samsung] September, 2007 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Technical Discussion - Network Formation and Device Joining] Date Submitted: [Sep 17, 2007] Source: [Chunhui Zhu] Company [Samsung] Address [75 W Plumeria Dr. San Jose, CA 95134] Voice:[408-544-5667], FAX: [408-544-5666], E-Mail: [c.zhu@samsung.com] Re: [] Abstract: [This is for the discussion on 802.15.5 low rate WPAN mesh.] Purpose: [for discussion and reference] 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. Chunhui Zhu / Samsung

Network Formation and Device Joining September, 2007 Network Formation and Device Joining Chunhui (Allan) Zhu September 17th, 2007 Samsung Electronics Chunhui Zhu / Samsung

September, 2007 Outline Services provided by 802.15.4 MAC for forming and joining a network Channel Scan Two approaches in mesh layer Comparison Conclusion Chunhui Zhu / Samsung

Services provided by 802.15.4 MAC September, 2007 Services provided by 802.15.4 MAC 802.15.4 provides the following mechanisms (primitives) for forming and joining a network Channel Scan Association/Disassociation Orphan Start Chunhui Zhu / Samsung

Channel Scan Energy Detection Scan Active Scan Passive Scan September, 2007 Channel Scan Energy Detection Scan For PAN Coordinator to select a channel on which to operate prior to starting a new PAN. Active Scan Allows a device to locate any coordinator transmitting beacon frames within its POS. Work only in non-beacon mode. Passive Scan It is the same as Active Scan except that the beacon request command is not transmitted. To be used only in beacon-enabled networks. Orphan Scan Allows a device to relocate its coordinator following a loss of synchronization. Chunhui Zhu / Samsung

Two Approaches (1/2) Approach 1 Current approach September, 2007 Two Approaches (1/2) Approach 1 Current approach 3 mesh layer primitives: Discovery (MAC: Active Scan) Start Mesh (MAC: ED Scan, Active Scan, and Start) Join (MAC: Active Scan, and Associate) Procedure: Use Discovery for gathering network information (Active Scan), such as which networks are out there. The result is not used for starting a mesh or a device. Use Start Mesh to find appropriate channel (ED Scan), find existing networks (Active Scan) and select PAN ID, then start the network (Start). Use Join to find existing networks (Active Scan), select and join the network (Associate). Chunhui Zhu / Samsung

Two Approaches (2/2) Approach 2: September, 2007 Two Approaches (2/2) Approach 2: Approach suggested during the comment resolution 3 mesh layer primitives (same as #1 but different meanings): Discovery (MAC: Active Scan, sometimes ED Scan) Start Mesh (MAC: Start) Join (MAC: Associate) Procedure: Step 1: Use Discovery to find existing networks (Active Scan), if PAN found, join it (step 3); if PAN not found, MC-capable: ED Scan, start a new one (step 2). Non-MC-capable: joining failed. Wait and try to join again. Step 2: Use Start Mesh to start a mesh network (Start). Step 3: Use Join to join the network (Associate). Chunhui Zhu / Samsung

Comparison Approach 1 Approach 2 Advantages Disadvantages September, 2007 Comparison Approach 1 Approach 2 Advantages Each mesh layer primitive has a clear function. One primitive for one completed process. NHL does not need to participate in the intermediate process. By using the results from Discovery primitive, Start Mesh and Start Device do not need to scan again (no function overlap). Disadvantages Result of Discovery not used for starting a network or a device. Some function overlaps in different primitives. Use two primitives (processes) for one process (start mesh or start device). Discovery results will be sent to the NHL for it to issue the second primitive. NHL has to involve in the intermediate process. This is an extra burden for the NHL. Chunhui Zhu / Samsung

September, 2007 Conclusion Prefer to keep the current solution for mesh network forming and device joining processes. Chunhui Zhu / Samsung

September, 2007 TG Conclusion During the discussion, the group came to the following conclusion: Take the first approach with the following modification. Make the active scan (at MAC layer) of the Join primitive optional. Add two more fields to the Join primitive A DirectJoin flag The device address of the parent node this node wants to join directly. This approach allows flexibility of either joining an specific parent node directly or joining the existing network based on the result of active scan. Modified Operation of this approach The NHL can decide whether to join a specific node directly or join an existing network based on the result of active scan. If the DirectJoin flag is set and a parent device address is provided in the Join primitive, the active scan will be skipped and the device will join the parent node directly (The next higher layer can do this because the Discovery primitive can provide channel conditions for it to make a decision on which parent node to join). Otherwise, the active scan will be performed and the result will be used for joining the network. Chunhui Zhu / Samsung