Large-Scale Distributed Internet-based Discovery Mechanism for Dynamic Spectrum Allocation

Scarcity of frequencies and the demand for more bandwidth is likely to increase the need for devices that utilize the available frequencies more efficiently. Radios must be able to dynamically find other users of the frequency bands and adapt so that they are not interfered, even if they use different radio protocols. As transmitters far away may cause as much interference as a transmitter located nearby, this mechanism can not be based on location alone. Central databases can be used for this purpose, but require expensive infrastructure and planning to scale. In this paper, we propose a decentralized protocol and architecture for discovering radio devices over the Internet. The protocol has low resource requirements, making it suitable for implementation on limited platforms. We evaluate the protocol through simulation in network topologies with up to 2.3 million nodes, including topologies generated from population patterns in Norway. The protocol has also been implemented as proof-of-concept in real Wi-Fi routers.Comment: Accepted for publication at IEEE DySPAN 201

Game Theoretical Approaches for Wireless Networks

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2017. 2. 김성철.In this dissertation, I introduce three algorithms, which are connectivity reconstruction game (CRG), adaptive sector coloring game (ASCG), and asymmetric transmission game (ATG), by mainly using supermodular game and exact potential game with considerations of various objectives (e.g., energy consumption and interference management) in wireless sensor and cellular networks. My main contributions are threefold: 1) connectivity relaxation (energy saving) in wireless localization2) intercell interference coordination in wireless cellular networks3) interference minimization in wireless ad-hoc relay networks. The corresponding explanations are as follows. 1) In geographically dense and energy limited wireless sensor networks, connectivity based localization with full power transmission can be inefficient in terms of energy consumption. In this work, I propose a distributed power control based connectivity reconstruction game, which takes into considerations of both energy efficiency and the quality of localization. The proposed scheme results in a better performance with an improved 61.9% reduction in energy consumption while maintaining the performance of localization at a level similar to the conventional algorithm with full power transmission. 2) Inter-cell interference coordination (ICIC) is a promising technique to improve the performance of frequency-domain packet scheduling (FDPS) in downlink LTE/LTEA networks. However, it is difficult to maximize the performance of FDPS using static ICIC schemes because of insufficient consideration of signal-to-interference-and-noise ratio (SINR) distribution and user fairness. On the other hand, dynamic ICIC schemes based on channel state information (CSI) also have difficulty presented in the excessive signaling overhead and X2 interface latency. In order to overcome these drawbacks, I introduce a new concept of ICIC problem based on geometric network information (GNI) and propose an ASCG as a decentralized solution of the GNI based ICIC problem. Furthermore, I develop an ASCG with a dominant strategy space noted as ASCGD to secure a stable solution through proving the existence of Nash equilibrium (NE). The proposed scheme provides better performance in terms of system throughput gain of up to about 44.1%, and especially of up to about 221% for the worst 10% users than static ICIC schemes. Moreover, the performance of the CSI based ICIC, which require too much computational load and signaling overhead, is only 13.0% and 5.6% higher than that of ASCG-D regarding the total user throughput and the worst 10% user throughput, respectively. The most interesting outcome is that the signaling overhead of ASCG-D is 1/144 of dynamic ICIC schemes one. 3) In this work, I introduce the new concept of temporal diversity utilization based on asymmetric transmission to minimize network interference in wireless ad-hoc networks with a two-hop half-duplex relaying (HDR) protocol. Asymmetric transmission is an interference-aware backoff technique, in which each communication session (source-relay-destination link) adaptively chooses a certain subset of spectrallyorthogonal data streaming which should be delayed by the duration of one time-slot (i.e., half of one subframe). I design the problem in the HDR scenario by applying the concept of asymmetric transmission, and evaluate the game-theoretical algorithm, called ATG, to derive the suboptimal solution. I show that ATG is an exact potential game, and derive its convergence and optimality properties. Furthermore, I develop an approximated version of ATG (termed A-ATG) in order to reduce signaling and computational complexity. Numerical results verify that two algorithms proposed showsignificant synergistic effects when collaborating with the conventional methods in terms of interference coordination. Ultimately, the energy consumption to satisfy the rate requirement is reduced by up to 17:4% compared to the conventional schemes alone.1 INTRODUCTION 1 1.1 Application of Supermodular Game for Connectivity Relaxation in Wireless Localization 2 1.2 Application of Exact Potential Game for Effective Inter-Cell Interference Coordination in Wireless Cellular Networks 3 1.3 Application of Exact Potential Game for Interference Minimization in Wireless Ad-hoc Relay Networks 7 1.4 Dissertation Outline 11 2 APPLICATION OF SUPERMODULAR GAME: Distributed Power Control based Connectivity Reconstruction Game inWireless Localization 13 2.1 Brief Introduction 13 2.2 System Model 13 2.3 Proposed Power Control Algorithm 14 2.3.1 Reliability Function 14 2.3.2 Game Formulation 15 2.3.3 Convergence Properties of CRG 17 2.4 Simulation Results 20 3 APPLICATION OF EXACT POTENTIAL GAME: Adaptive Sector Coloring Game for Geometric Network Information based Inter-Cell Interference Coordination in Wireless Cellular Networks 24 3.1 Brief Introduction 24 3.2 Network Model 26 3.2.1 System Preliminaries 26 3.2.2 Determination of Time Policy 27 3.2.3 Two-Stage Framework of RB Allocation 27 3.3 PROBLEM FORMULATION: Geometric Network Information based ICIC 28 3.3.1 Outline 28 3.3.2 What Is the GNI 28 3.3.3 Temporal Perspective: Why GNI 29 3.3.4 Spatial Perspective: How do I Design a Suitable Utility Function 29 3.3.5 GNI based ICIC Problem 33 3.4 ADAPTIVE SECTOR COLORING GAME 33 3.4.1 Design of ASCG 33 3.4.2 ASCG with a Dominant Strategy Space 35 3.4.3 Summary of System Operation 40 3.5 PERFORMANCE EVALUATION 41 3.5.1 Simulation Settings and Baselines for Comparison 41 3.5.2 SINR Distribution and Average User Throughput 43 3.5.3 Signaling Overhead for ICIC and FDPS 47 3.5.4 Reduction of Feasible ASCG Strategy Space 49 4 APPLICATION OF EXACT POTENTIAL GAME: Asymmetric Transmission Game for Interference Coordination in Wireless Ad-hoc Relay Networks 51 4.1 Brief Introduction 51 4.2 Problem Formulation 52 4.2.1 System Preliminaries 52 4.2.2 The Concept of Asymmetric Transmission for Interference Coordination: A Simple Example 53 4.2.3 Optimization Problem 54 4.3 Asymmetric Transmission Game 55 4.3.1 Game Formulation 55 4.3.2 Convergence and Optimality Properties of Asymmetric Transmission Game 55 4.3.3 Approximated Version of Asymmetric Transmission Game . . 58 4.4 Simulation Results 61 4.4.1 Parameters Settings 61 4.4.2 Network Interference in One-shot Game 62 4.4.3 Individual Power Consumption in One-shot Game 66 4.4.4 Total Energy Consumption in 1000-shot Games 70 4.4.5 Complexity Analysis for Varying K and M 71 5 CONCLUSION 74 Appendix A Derivation of number of partitions for extracting the dominant feasible strategy set 76 Appendix B Derivation of the cardinal number of the dominant feasible strategy set 78 Appendix C Existence of NE in ASCG-D 79 Appendix D The Required Signaling overhead of ASCG-D 82 Bibliography 83 Abstract (In Korean) 93Docto