July 2009 doc.: IEEE 802.19-09/xxxxr0 July 2009 On-demand spectrum contention: a scalable and fair spectrum sharing protocol for TVWS coexistence Date: 2009-07-14 Authors: 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. Wendong Hu, STMicroelectronics Ari Ahtiainen, Nokia

July 2009 doc.: IEEE 802.19-09/xxxxr0 July 2009 Abstract This contribution presents an overview of the On-demand Spectrum Contention (ODSC) protocol for distributed and dynamic spectrum sharing in TV white-space. Wendong Hu, STMicroelectronics Ari Ahtiainen, Nokia

Outline Overview of ODSC protocol Illustrations of ODSC protocol July 2009 Outline Overview of ODSC protocol Illustrations of ODSC protocol Performance evaluation of ODSC protocol Conclusion Wendong Hu, STMicroelectronics

Inter-Network Spectrum Sharing in TVWS July 2009 Inter-Network Spectrum Sharing in TVWS Wendong Hu, STMicroelectronics

Overview of On-demand Spectrum Contention Protocol July 2009 Overview of On-demand Spectrum Contention Protocol Message-based, demand-driven, distributed spectrum sharing protocol TVBD cells exchange contention messages, containing random contention numbers, to determine their rights of media access. Designed for fair, low-overhead, QoS-aware spectrum sharing among the coexisting network cells. Categorized into Coarse-grain (channel-based) and Fine-grain (frame-based) sharing The basic principle is adopted in IEEE 802.22 draft standard [1] Wendong Hu, STMicroelectronics

Example of Channel-based ODSC July 2009 Example of Channel-based ODSC Wendong Hu, STMicroelectronics

Example of Frame-based ODSC July 2009 Example of Frame-based ODSC Provide a better QoS as compared to the channel-based approach Wendong Hu, STMicroelectronics

Message Flow of ODSC Protocol July 2009 Message Flow of ODSC Protocol Wendong Hu, STMicroelectronics

Spectrum Contention Algorithm July 2009 Spectrum Contention Algorithm Spectrum Contention Number Generation SCN = RANDOM (0, 2^16 ). Wendong Hu, STMicroelectronics

Properties of ODSC Protocol July 2009 Properties of ODSC Protocol Require a standardized protocol for all (both heterogeneous and homogeneous) coexisting networks Require a reliable and efficient inter-network communication mechanism for coexistence. Require synchronized frame / superframe structure when finer grain spectrum sharing is employed. Wendong Hu, STMicroelectronics

Performance Evaluation – Tool & Settings July 2009 Simulation Tool NS2 (Network Simulator) [2] Model for IEEE 802.22 with ODSC implemented Simulation Parameters Single channel sharing Size of super-frame: 16 frames Frame size: 10ms Self-coexistence Window size: 1ms Simulation time: 10,000 seconds Coexistence Scenarios (see more next slide) Complete Graph scenarios Cycle Graph scenarios Wheel Graph scenarios Evaluation Metrics Fairness and Convergence Time Wendong Hu, STMicroelectronics

Coexistence Scenarios July 2009 Coexistence Scenarios Complete Cycle Wheel Wendong Hu, STMicroelectronics

Performance Evaluation – Results (1) July 2009 Performance Evaluation – Results (1) Wendong Hu, STMicroelectronics

Performance Evaluation – Results (2) July 2009 Performance Evaluation – Results (2) Wendong Hu, STMicroelectronics

Performance Evaluation – Results (3) July 2009 Performance Evaluation – Results (3) Wendong Hu, STMicroelectronics

Fairness and Convergence Time July 2009 Fairness and Convergence Time [2] Wendong Hu, STMicroelectronics

Conclusion ODSC Protocol Efficient Fair Scalable Stable July 2009 enable efficient, scalable, and fair inter-network spectrum sharing Efficient Simple contention process (random number exchange) Contentions are in parallel with data transmissions Avoid collisions and the hidden node problem Fair Random number comparisons On-demand iterative contention process Scalable Distributed decision making, no central arbiter needed. Stable Cooperation among networks to achieve the goals of fairness and efficiency of spectrum sharing Wendong Hu, STMicroelectronics

July 2009 References [1] IEEE P802.22™/ DRAFTv2.0 Draft Standard for Wireless Regional Area Networks Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Policies and procedures for operation in the TV Bands [2] “The network simulator – ns-2,” http://www.isi.edu/nsnam/ns/v2.28 [3] Jain, R., Chiu, D.M., and Hawe, W. (1984) A Quantitative Measure of Fairness and Discrimination for Resource Allocation in Shared Systems. DEC Research Report TR-301 Wendong Hu, STMicroelectronics