Physical Layer Security in Nonorthogonal Multiple Access Wireless Network with Jammer Selection

Langtao Hu,Chunsheng Chen,Xin Zheng

doi:10.1155/2019/7869317

Abstract

The physical layer security of downlink nonorthogonal multiple access (NOMA) network is analyzed. In order to improve the secrecy probability, friendly jammers are jointed in the NOMA network. Two jammer schemes are proposed in the NOMA network. All the jammers transmit jamming signal without jammer selection in the first scheme (NO JS scheme). Jammers are selected to transmit jamming signal if their interfering power on scheduled users is below a threshold in the second scheme (JS scheme). A stochastic geometry approach is applied to analyze the outage probability and the secrecy probability. Compared with the NO JS scheme and traditional scheme (without jointing jammers), the jammer selection scheme provides a good balance between the user outage probability and secrecy probability. Numerical results demonstrate that the security performance of the two proposed schemes can be improved by jointing the jammers in the NOMA wireless network.

Highlights

We present Monte Carlo simulations to evaluate the performance of the proposed scheme, and analytical results are illustrated and validated with extensive simulations in nonorthogonal multiple access (NOMA) network. e default parameters are listed in Table 1 unless otherwise stated
Our first proposed scheme is that all jammers are active without jammer selection in NOMA network, which is marked as “NO JS scheme.”
Default value 1/km2 10/km2 11/km2 100/km2 46 dBm 23 dBm 0.3 4 0.1 km scheme is that some jammers are active with jammer selection in NOMA network, which is marked “JS

Summary

System Model

E UE and EVE locations are distributed as an independent homogeneous PPP ΦU and ΦE with densities λU and λE, respectively. Existing results have shown that the NOMA group with more than two UEs may provide a better performance gain [18]. We assume λU ≫ λB so that a sufficient number of UEs can always be found to form the NOMA group in each cell. To enhance the security performance, friendly jammers are jointed in NOMA network. The threshold is the jammer exclusion zone around the scheduler user, i.e., ΦJS 􏽮j | j ∈ ΦJ, PJR−j,aUi < PJD− a,. ΦUs denotes the point process of scheduled users. UE1 is assumed to be with a better normalized channel gain. All hi are assumed to be i.i.d. ri is the distance between BS0 and UEi. ni is the additive noise

NOMA User Outage Probability

NOMA User Secrecy Probability

Simulation Results and Discussion