BB84 (Bennett and Brassard 1984) is one of the well known protocols of quantum keys distribution. It is built to allow two interlocutors commonly called Alice and Bob to share two similar binary keys and to detect the eavesdropper presence (the eavesdropper is commonly called Eve). However, Eve presence in a disturbed environment causes errors to the sifted keys and decreases the amount of secure information between Alice and Bob. One of the most important stages in BB84 protocol is to decide by using error probability estimation if we can continue the protocol phases or no. Indeed, this decision is function of some factors like: what is the amount of information that we will lose in the error correction phase? What is the degree of errors detected in our sifted keys? What is the origin of these errors: Eve strategy or the channel disturbance? For these reasons, we will study in this study some conditions to stop BB84 protocol in the context of depolarizing channel. We implement two types of eavesdropping strategy: Intercept and Resend and Cloning Attack.

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With the ever-increasing number of intelligent devices, extensive research efforts have been spent towards developing efficient resource allocation in underlying device to device communications. Centralised and distributed approaches have been proposed to improve the network performances through uplink and downlink schemes. However, the full-duplex resource allocation remains challenging. Here, a joint uplink-downlink resource block assignment for device to device communications is proposed. The device's geometric distribution via the Poisson point process is formulated and the optimization problem as a mixed strategy non-cooperative game is modelled. The proposed resource allocation scheme allows many device to device communication pairs to share the same cellular resource block but does not restrict their number in advance; it is determined dynamically according to the channel's capacity and interference condition. Inversely, a device to device communication transmitter can simultaneously be allocated many resource blocks according to its bandwidth requirement and the number of its antennas. Furthermore, the optimal amount of data and power transmitted by each device is calculated. The efficiency of this algorithm is evaluated through computer simulations, and the results demonstrate good performances in the spectral and energy efficiency with relatively low complexity and convergence time.

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