to avoid congestion situations in WSNs, two types of solutions are possible:
- Use of an congestion-oriented Routing Algorithm,
- The use of a congestion-aware Objective Function in the Routing Protocol RPL.
My little list of literature may help.
H. A. Al-Kashoash, Y. Al-Nidawi and A. H. Kemp: Congestion-Aware RPL for 6LoWPAN Networks , IEEE Wireless Telecommunications Symposium (WTS), Apr. 2016; DOI: 10.1109/WTS.2016.7482026
http://ieeexplore.ieee.org/document/7482026/
W. Tang, X. Ma, J. Huang and J. Wie: Toward Improved RPL: A Congestion Avoidance Multipath Routing Protocol with Time Factor for Wireless Sensor Networks, Journal of Sensors, Vol. 2016, Jan. 2016; DOI: 10.1155/2016/8128651
H. A. A. Al-Kashoash, M. Hafeez and A. H. Kemp: “Congestion Control for 6LoWPAN Networks: A Game Theoretic Framework”, IEEE Internet of Things Journal, DOI 10.1109/JIOT.2017.2666269, 2017
F. Ren, T. He, S. Das and C. Lin: Traffic-Aware Dynamic Routing to Alleviate Congestion in Wireless Sensor Networks, IEEE Transactions on Parallel and Distributed Systems, Vol. 22, No. 9, Sep. 2011