1. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 1 Coexistence in TV White Space Date: 2008-12-17 Authors:

2. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 2 Abstract There are likely to be multiple non- interoperable standards operating in the TV white space spectrum It is important to provide mechanisms to facilitate coexistence between these systems

3. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 3 Scope of Coexistence Two Network designed according to different standards –Network A –Network B Scope of coexistence work –Coexistence between Network A and Network B Not within scope of coexistence work –Coexistence between Network A and Incumbent systems –Coexistence between Network A and another Network A

4. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 4 Categories of Coexistence Mechanisms 1.Non-cooperative Each network attempts to maximize its performance Examples: selection of channels with limited interference, spatial interference cancelation or beam forming, adaptive frequency hopping, etc. 2.Cooperative – Rules Based Agree to follow a set of rules without having to exchange messages Examples: listen-before-talk, divide up the spectrum a priori, transmit power control, etc. 3.Cooperative – Message Based Negotiation of which channels to use Negotiation on time domain sharing Negotiation of transmit power control

5. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 5 Working Group Cooperation Non-cooperative techniques do not require WGs to agree on any network behavior – However, could limit coexistence Rules-based techniques requires agreeing on network behavior but does not require interoperability Message-based techniques provides the most flexibility but also requires a control channel between networks. Two options for control channel 1.Simple common PHY 2.Backhaul since all networks have Internet access and are location aware

6. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 6 Adaptive (Cognitive) versus non-Adaptive Coexistence A adaptive coexistence mechanism adapts its transmissions to enhance coexistence, based on its awareness to local spectrum activity –Adaptive frequency hopping in Bluetooth –Exponential back-off in 802.11 A non-adaptive mechanism has fixed behavior –Divide up the spectrum a priori between fixed and portable Adaptive is preferred –Full utilization of spectrum when Network A is the only network in the area –Sharing of spectrum when Network A and Network B are in a common area

7. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 7 Cognitive Coexistence in TV White Space Cognitive requires –Awareness –Adaptation Methods of Awareness –Observe spectrum –Observe location –Observe location of other networks (control channel) Adaptation parameters –Selection of channel –Bandwidth –Transmit power –Time of transmission –Modulation and coding rate

8. sg-whitespace-08/0006r0 Submission December 2008 Steve Shellhammer, QualcommSlide 8 Recommendations Investigate –Methods of awareness (autonomous and control channel) –Methods of adaptation Evaluate effectiveness of rules on network behavior –Rules for awareness –Rules for adaptation based on set of conditions