I. INTRODUCTION
A. Related Surveys in the Literature
B. Survey Structure

II. INTERFERENCE TAXONOMY & PROBLEM STATEMENT

III. SPECTRUM SHARING: A SYSTEM-LEVEL VIEW
A. Regulatory Framework Constraints & Spectrum Sharing at Layer 0
B. Spectrum Sharing at Layer 2
C. Spectrum Sharing and Interference Mitigation at Layer 1
D. Constraints of Applications at Layer 7
E. Constraints of Business Models and Social Practices at Layer 8
F. Literature Review Structure

V. LITERATURE REVIEW OF INTER-TECHNOLOGY COEXISTENCE IN A SPECTRUM COMMONS
A. Coexistence with Low Traffic Technologies
B. Coexistence among Broadband Technologies
C. Summary & Insights

VI. DISCUSSION & FUTURE RESEARCH DIRECTIONS
A. A System-Level View of Inter-Technology Spectrum Sharing
B. Recent Trends in Spectrum Sharing
C. Challenges for Spectrum Sharing in a Spectrum Commons
D. Layer 2 Spectrum Sharing in a Spectrum Commons
E. Layer 1 Spectrum Sharing in a Spectrum Commons
F. Performance Evaluation of Spectrum Sharing Mechanisms
G. Other Open Challenges

VII. CONCLUSIONS