I. Introduction  
II. Related IIoT Testbed Surveys  
A. IIoT, CPS, ICS and WSAN  
B. CPS Testbed Surveys  
C. ICS Testbed Surveys  
D. WSAN Testbed Surveys  
III. Industrial IoT Overview  
A. IIoT Architecture  
B. IIoT Communication Protocols  
C. Resource Management in IIoT Systems  
D. IIoT Testbed Classification  
IV. TSN-based IIoT Testbeds  
A. General TSN Testbeds  
B. OPC-UA-TSN Testbeds  
C. Wireless TSN Testbeds  
V. IEEE 802.15.4-based IIoT Testbeds  
A. IEEE 802.15.4-based Testbeds  
B. IEEE 802.15.4e-based Testbeds  
VI. IEEE 802.11-based IIoT Testbeds  
A. Industrial Platforms  
B. Simulators  
C. Academic SDR Platforms  
D. FGPA-based SDR Platforms  
VII. 5G-based IIoT Testbeds  
A. Large-Scale 5G-based IIoT Testbeds  
B. Small-Scale 5G-based IIoT Testbeds  
VIII. Suggestions and Practices  
IX. Conclusion