  Recently, physical layer security based approaches have drawn considerable
attentions and are envisaged to provide secure communications in the wireless
networks. However, most existing literatures only focus on the physical layer.
Thus, how to design an effective transmission scheme which also considers the
requirements from the upper layers is still an unsolved problem. We consider
such cross-layer resource allocation problem in the multi-user downlink
environment for both having instantaneous and partial eavesdropping channel
information scenarios. The problem is first formulated in a new security
framework. Then, the control scheme is designed to maximize the average
admission rate of the data, incorporating delay, power, and secrecy as
constraints, for both non-colluding and colluding eavesdropping cases in each
scenario. Performance analysis is given based on the stochastic optimization
theory and the simulations are carried out to validate the effectiveness of our
scheme.
