18 July 2007 doc IEEE 802 15 -07 758 r

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Discussion on Coexistence Mechanism] Date Submitted: [9 July 2007] Source: [(alphabetical list) Beom. Jin (Paul) Jeon 1, James P. K. Gilb 2, Jeff Gilbert 3, John Marshall 4 Yong. Hoon Kim 5] Company [1, 5 LG Electronics Inc. , 2, 3, 4 Si. BEAM, Inc. ] Address [1, 516 Woomyeon-Dong, Seocho-Gu, Seoul, Korea, 2, 3, 4555 N Mathilda Ave Ste 100, Sunnyvale, CA 94085] Voice: [1, 5+82 2 526 4065, 2, 3, 4+1 408 245 3120], FAX: [], E-Mail: [1 bjjeon at lge dot com, 2 gilb at ieee dot org, 3 jgilbert at sibeam dot com, 4 jmarshall at sibeam dot com, 5 yonghkim 2002 at empal dot com] Re: [] Abstract: [Discussion topic on the purposes and methods of coexistence of multiple PHY systems in 60 GHz band. ] Purpose: [To initiate open discussion on the optimal coexistence mechanism in mm. Wave] Notice: This document has been prepared to assist the IEEE P 802. 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 P 802. 15. TG 3 c Presentation 1 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Overview • A view on coexistence – Principles of coexistence & related issues • Coexistence Mechanism – Optimal coexistence mechanism discussion • Concluding Remark TG 3 c Presentation 2 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Background • In the last meeting : – 16 PHY Proposals were presented – Their channelizations, modulation schemes, coverage and bit rate were different. – 8 of them declared, in the content, that they would merge with other candidates. • In 5 proposals : – Several coexistence mechanisms were proposed but the targeting coexistence were slightly different. TG 3 c Presentation 3 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Levels of Coexistence Mechanism Coexistence In the Same space By Simple Detect and Avoid Power Detect Preamble Correlation PHY Identifier in Preamble f Coexistence In the Same Frequency Channel By mm. Wave’s Inherent Directionality Coexistence In the Same Piconet By Sharing Scheduling Information Sending multiple beacons for each PHY t Using additional common PHY mode TG 3 c Presentation 4 t LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 The key principles for coexistence • What are the key features required for two heterogeneous PHY systems to coexist? • The human world case study : – mutual respect for territorial integrity – mutual non-aggression – non-interference in each other’s internal affairs – equality and mutual benefit – peaceful co-existence The Five Principles of Peaceful Coexistence, “Panchsheel”, from the peace agreement between China and India in 1954 TG 3 c Presentation 5 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Mutual respect for territorial integrity • What will be the territory in the wireless world? – A territory is a defined area considered to be a possession of, usually legally administered by, a person, organization, …. – In the 802. 15. 3 c world, the beacon coverage area of a certain network may be considered as a territory of it. – Issue #1 : How to identify the territories of heterogeneous PHY networks. – Issue #2 : Un-identical beacon coverage – Issue #3 : Stations in the edge TG 3 c Presentation 6 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Mutual non-aggression • Fortunately, at this moment, there is no way to attack any heterogeneous station which might have entered (or initiated a network) accidentally in the already occupied channel. – Issue #4 : Even with “Listen before configuration” mechanism, in case of miss-configuration, how to detect the interference and who shall surrender the channel if it detects interference. TG 3 c Presentation 7 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 non-interference in each other’s internal affairs • Issue#5 : How to avoid interference – Just move to the other empty channel sub issue #5 -1 : Finite usable channels – Or share the channel with the existing network by using empty time slot in TDMA manner sub issue #5 -2 : How to share the scheduling information among heterogeneous stations – Or just use the same channel hoping that the directivity of mm. Wave beam will minimize the interference. sub issue #5 -3 : How to guarantee no-interference. - Beacons may be omni-directional - Depends on the locations of devices TG 3 c Presentation 8 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 equality and mutual benefit • This means that it is not desirable to have un -equality like below : “Devices using PHY ‘A’ can go without any coexistence measures but others must detect PHY ‘A’ network and avoid interference with it by all costs. ” Or, “I have no coexistence measure at all. So, please avoid me if possible although I cannot avoid you” ( = “My car has no braking system. ”) Issue #2 : The un-identical beacon coverage Issue #4 : Then who will surrender the channel TG 3 c Presentation 9 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Solution comparison (example) Solution 1. Simple and no-interference but finite useable channel issue must be considered. Solution 2. If we can guarantee no-interference, it is optimal for mm. Wave. Solution 3. Coexist in the same piconet method is good for many coexistence issues except its complexity. Besides the complexity, from the application point of view, different PHY shares channel time, their real through put might not be served at its maximum and also there is no reason to share the superframe time in view of application. In addition, un-identical beacon coverage issue must be addressed. TG 3 c Presentation 10 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal coexistence mechanism for mm. Wave? • As simple as possible thinking of the frequency of interference case. (How many mm. Wave communication application will be running in the same room and at the same time? ) • Different levels of sensitivity shall be taken into account. HD video streaming may be more sensitive to interference than file transfer. Slow file transfer may be tolerable but defects on the movie screen cannot be tolerated. (Users willingly wait for 2 hours downloading a cool movie file. ) • Making the best of 802. 15. 3 c characteristics. We have coordinators and omni-directional beacons but our mm. Wave beams used for application data transfer are highly directional. • A structure with high flexibility for optional usage and backward compatibility. TG 3 c Presentation 11 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussions • Issue #1 : How to identify the territories The coordinator may add some dedicated common codes ahead of the beacon preambles to identify its service area and sensitivity grade (for example, Video Streaming or File Transfer). By this common code, stations using even heterogeneous PHY can identify the service area and its sensitivity to interference and can choose to move to other empty channel or choose to stay but in very “cautious manner”. For other PHYs only Common Codes for Sensitivity & Area For our own PHY Specific PLCP Preamble Portion PLCP Header BEACON PSDU Beacon Starting Time TG 3 c Presentation 12 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussions • Issue #2 : Un-identical beacon coverage The beacon coverage is enough to cover only its service area. And we can repeat only the “common codes for sensitivity & area” portion to make identical detection coverage regardless of beacon coverage. Common Codes for S&A PLCP Preamble PLCP Header TG 3 c Presentation 13 BEACON PSDU LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Repetition of Code (example) Walsh Length =2 Barker 13 Walsh Length =4 Barker 13 TG 3 c Presentation 14 Barker 13 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussions • Issue #3 : Station at the edge The station can report its intolerable interference (i. e. channel condition) to its coordinator and persuade the coordinator to change its operating channel. But if the coordinator can secure it service area beyond its beacon coverage, the probability of this kind of problem can be reduced. TG 3 c Presentation 15 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussions • Issue #4 : How to detect interference and Who will surrender The coordinator can notify the interference to the interference source using “Alert Codes”. And the coordinator in the “cautious manner” will be listening to detect the interference (i. e. whether it causes interference or not), if it detects the interference, it can take adequate actions like below : - Reduce TX power - Reduce Data Rate (i. e. TX duty) - Stop transmitting and move to the other channel For other PHYs only For our own Common Codes for Alert PHY Specific PLCP Preamble Portion PLCP Header BEACON PSDU Beacon Starting Time TG 3 c Presentation 16 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussions • Issue #5 : How to avoid interference 1 If a station detect a high sensitivity network in a channel, it may choose to move to another empty channel. But the useable channel number is finite, so it may want to stay in the same channel. In that case, the omni-directional beacons may conflict with each other. So, for the omni-direction beacons of multiple PHYs, we may set up multiple narrow band in one channel and let them use these narrow band channels for their beacon signaling. TG 3 c Presentation 17 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussion • Issue #5 : How to avoid interference 2 Further more, we can dedicate a certain narrow band channel (red) for the beacon of the most sensitive application. We can make the coordinators (yellow and green) of non sensitive application (like file transfer) always monitor the dedicated beacon channel (red) to detect interference to the sensitive application like HD video transmission. TG 3 c Presentation 18 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Optimal Solution Discussion In ? ? years, … In 3 years, … OR? Not so many devices in a house. Couple of devices in one room. TG 3 c Presentation 19 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Flow Chart (Example) Power On Searching Channels Your Coordinator is Found? Yes Sensitivity level is acceptable? Associate with it! No No No Are there any empty channel? Yes Can it be upgrade? Yes Go there and Start Piconet there! No If all useable Channels are occupied then choose most insensitive channel TG 3 c Presentation 20 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Flow Chart (Example)-Cont’ If all useable Channels are occupied then choose most insensitive channel Lowest sensitivity level is high? Yes My sensitivity level also is high? No Yes My sensitivity level is high? Select Highest Priority Beacon channel and start piconet there No Just select empty Beacon channel and start piconet there You may use this channel but Qo. S cannot be guaranteed. Start Piconet there but periodically monitor the highest priority beacon channel Are there any interference Alert? No Reduce TX Power or Reduce date rate (or duty) or Find other channel to share! Yes Keep using it! TG 3 c Presentation 21 LG Electronics & Si. BEAM

18/July/2007 doc. : IEEE 802. 15 -07/758 r 2 Concluding Remark • We, together, would better develop the optimal coexistence mechanism for our mm. Wave WPAN. – It should be able to answer the known issues. – It should be as simple as possible with respect to the issue’s severity. – The sensitivity of the each application should be reflected. – It should make the best of 802. 15. 3 c WPAN characteristics. – It should be flexible structure for optional usage. • Next Step : We’d like to proceed to the optimal solution proposal with many interested individuals by the next meeting. TG 3 c Presentation 22 LG Electronics & Si. BEAM