Aiming at wireless sensor networks（ WSNs） node congestion problem of TCP transmission mechanism

on the basis of transmission layer

combine with SNR parameter of physical layer to estimate channel condition

and constantly adjust transmission model

implement cross-layer control. This cross-layer method makes full use collaboration relationship between layers of WSNs which changes the previous single layer congestion control method

use discrete sliding mode control structure model control based on self adaptive reaching-law as controller

which is simple and easy to implement. Simulation results show that the cross-layer congestion control method has characteristics of fast response speed

small delay

good robustness.