  Wireless networks with the consideration of social relationships among
network nodes are highly appealing for lots of important data communication
services. Ensuring the security of such networks is of great importance to
facilitate their applications in supporting future social-based services with
strong security guarantee. This paper explores the physical layer
security-based secure communication in a finite Poisson network with social
friendships among nodes, for which a social friendship-based cooperative
jamming scheme is proposed. The jamming scheme consists of a Local Friendship
Circle (LFC) and a Long-range Friendship Annulus (LFA), where all legitimate
nodes in the LFC serve as jammers, but the legitimate nodes in the LFA are
selected as jammers through three location-based policies. To understand both
the security and reliability performance of the proposed jamming scheme, we
first model the sum interference at any location in the network by deriving its
Laplace transform under two typical path loss scenarios. With the help of the
interference Laplace transform results, we then derive the exact expression for
the transmission outage probability (TOP) and determine both the upper and
lower bounds on the secrecy outage probability (SOP), such that the overall
outage performances of the proposed jamming scheme can be depicted. Finally, we
present extensive numerical results to validate the theoretical analysis of TOP
and SOP and also to illustrate the impacts of the friendship-based cooperative
jamming on the network performances.
