A Cooperation Mechanism for Coexistence between Secondary User Networks on TVWS

1. A Cooperation Mechanism for Coexistence between Secondary User Networks on TVWS Authors: Date: 2009-07-14 Notice:This document has been prepared to assist IEEE 802.19. 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. Ari Ahtiainen, Nokia

2. Abstract This presentation deals with coexistence between secondary user networks operating in TVWS. Database is believed to be the solution to protect the primary users of the TVWS spectrum. We doubt its applicability to address coexistence problems between all secondary users. In this presentation we present an idea of a cooperation network to address the problems in a distributed and more flexible manner. Ari Ahtiainen, Nokia

3. Outline • Problem description (and some terminology) • Solution proposal • Coexistence network between heterogeneous TVBD networks • Outline of the solution • Cooperation Radio and Network • Characteristics and requirements • Selected functionalities • Conclusions Ari Ahtiainen, Nokia

4. Terminology and Goal Setting • Coexistence – Effective common use of the spectrum among networks of TV band devices • Coexistence Mechanism – A technique to provide effective sharing of the spectrum between networks of TV band devices. Examples include DFS, TPC, listen before talk, TDMA, Message-based Spectrum Contention, etc. Goal setting by 802 EC (March 2009) • Support for coexistence mechanisms so that multiple technologies can effectively utilize the spectrum is important Ari Ahtiainen, Nokia

5. Problem Description • In TVWS the operation environment will be very heterogeneous • Multiple TVBD networks and technologies will coexist on the TVWS bands • Radio technologies will evolve towards frequency agility • Radio channel status is very local • Propagation environment is very local • TVBD networks can be very dynamic • Heterogeneous systems require cooperation mechanisms • Cooperation mechanism is the common etiquette for the TVBD networks • Radio-level listen before talk is not enough • Cooperation enables • Sharing of spectrum sensing responsibilities (who and when) • Possibility for common quiet periods • Spectrum resource use negotiation (who and what) • Accommodates TDM, FDM, etc. schemes Ari Ahtiainen, Nokia

6. Why Distributed Cooperation? • Due to the heterogeneity, effective centralized cooperation will become complex • A lot of radio measurement data need to be delivered to the centralized controller • The controller needs to have means to analyze radio environment in every possible location upon requests • Distributed cooperation will provide a more feasible solution • Can accommodate large amount of networks • Mobile devices with sensing only capability would require another radio to access the database • No single point of failure • The best and up to date knowledge about local radio environment is available in devices locally present • Local radio environment information can be measured by the devices in accurate and timely manner Ari Ahtiainen, Nokia

7. Solution Proposal – Introduction • Cooperation with Cognitive Cooperation Radio Network (CCRN) • Control (only) network dedicated for cooperation signaling between TVBD networks • Secondary user networks agree with each other locally about the resource sharing • CCRN enables cooperation information flow between the networks • Devices looking for connectivity alternative obtain the required information from CCRN • Messages on CCRN are defined to be independent of the internal architectures of the networks to be connected • Targeted to connect different kinds of TVBD networks • Access or non-access networks • Infrastructure based or device only networks • Operated or ad hoc networks Ari Ahtiainen, Nokia

8. WMAN Base station (Fixed device) User network 1: WMAN WMAN portable (Mode I or Mode II device) WLAN Access Point (Mode II device) WLAN portable (Mode I device) User network 2: WLAN Ad-hoc node (Mode II or Sensing-only device) User data link Cognitive Cooperation Radio link User network 3: WAHN Solution Proposal – CCRN Concept • CCRN consists of nodes from all TVBD networks operating in the same area • Each node has the capability of using the CCRN for cooperation signaling Ari Ahtiainen, Nokia

9. CCRN – Connectivity • Physical connectivity • Narrowband radio, dedicated for CCRN operation, especially between heterogeneous user networks • Frequency assignment to CCRN • most efficient solution is to assign dedicated band(s) for the CCRN operation • In each user network at least one node is actively connected to the CCRN • Logical connectivity • All the nodes connected to user networks have access to information on CCRN • Nodes not yet connected to any user networks can also access the information on CCRN • Encapsulation of CCRN information depends on the user network (in-band communication) Ari Ahtiainen, Nokia

10. CCRN – Characteristics • Target is to have a lightweight, power efficient solution • Narrowband, low-capacity radio as a carrier is sufficient • Allows for stateless routing by message flooding over multiple radio links when needed • No QoS support required • All messages on CCRN assumed to be equally important Ari Ahtiainen, Nokia

11. CCRN – Usage • Initial access • To efficiently find out TVBD networks in complex heterogeneous environments • Collaborative spectrum sensing • To distribute the sensing responsibilities and results between participating nodes (possibly connected to different user networks) • Dissemination of local spectrum use policies • To ensure that all the nodes follow the same policies (if applicable) • Spectrum usage information and negotiation • To distribute the local spectrum map, and agree on shared spectrum utilization • Inter-network synchronization • To create spectrum sensing measurement period (quiet period), common to user networks • E.g. to support TDM-based coexistence schemes Ari Ahtiainen, Nokia

12. CCRN – What it Takes? • CCRN radio has unique characteristics that are not met with any existing standard radio • User data networks are heavyweight solutions for the CCRN • IEEE 802 architecture fits well in the CCRN requirements • Simple radio designed for CCRN • CCRN requires a frequency channel allocated to it • In the case of TVWS one narrowband channel should be allocated for CCRN • Small portion of 6 MHz channels enough Ari Ahtiainen, Nokia

13. Summary • Cognitive Cooperation Radio Network concept introduced • Important technology enabler for cooperative coexistence in heterogeneous cognitive radio ecosystems • Future work • Concept finalization and more detailed specifications • Detailed performance assessment • Regulatory impacts • Standardization • Proposed actions • IEEE 802.19 TAG is doing a study on Coexistence Mechanisms for 802 radios on White Space – scheduled to finish in November 2009 • Include further development of the CCRN-based coexistence schemes into the summary and recommendations from the .19 SG to 802 EC Ari Ahtiainen, Nokia

14. Further Info • Ahtiainen, A., Kasslin, M. et al, “Awareness Networking in Wireless Environments”, to appear in IEEE Vehicular Technology, September 2009. Ari Ahtiainen, Nokia