The rise of heterogeneity in technology, types of services, and coverage area of radio access in the Fifth Generation (5G) wireless communication, opens new challenges in optimising users’ access to the networks. To fully utilise the capacity of such rich field of wireless connectivity, mobile devices can not any more be confined with accessing only their previously agreed home operator’s infrastructure. On the other hand, and in order to keep up with the agility required to deliver promises in providing new services and applications, virtualization and softwarization are introduced in the 5G. To this end, we propose an on-the-fly Radio Resource Sharing (RRS) scheme between different mobile infrastructures so as to provide mobile devices with the freedom to access all available radio resources around them. Such on-the-fly RRS is empowered by employing the concepts of Software-defined Networking (SDN) and virtualization of radio access resources. We argue that the RRS service is a step forwards in achieving the convergence as foreseen by the 5G: convergence of SDN, virtualization, and wireless control, convergence of heterogeneous wireless infrastructure, and above all, convergence of different operators’ infrastructure in a transparent manner.

The proliferation of radio-enabled equipment, including sensors, controllers, actuators, mobile handhelds, etc., into the today's heterogeneous wireless network (HWN) has led to the support of different vertical services on-top of the same physical infrastructure. Such an approach increases the potential for enhanced multiplexing gains due to the joint utilization of multiple network tiers and their resources. However, it also links the availability of new services to the robustness of the HWN infrastructure against malicious attacks. In this paper, we study the impact of two prominent denial of service (DoS) attacks, the jamming and the black hole attack, on network coverage of multi-tier HWNs. In particular, we consider a HWN model of multiple tiers, where the locations of nodes belonging to each tier are modeled by a homogeneous Poisson Point Process (PPP) with known intensity. Each tier consists of regular nodes, jammers (disrupting downlink communications by transmitting at constant power), and black holes (appearing as regular nodes but without forwarding received packets to their legitimate destination). The type of nodes for a given network tier is given by a prescribed probability, whereas jammer and black hole nodes are considered to act independently from each other. We further focus on the challenging scenario where end users can access a limited number of network tiers, while we also allow different tiers to potentially utilize different spectrum bands. Assuming that successful service reception from a WNE belonging to a given network tier requires a minimum received signal quality threshold to be attained, which for analytical tractability we consider to be higher than the unit, we derive exact expressions and performance bounds on the coverage probability of random multi-tier HWNs with joint jamming and black hole attacks depending on the capability of network nodes to detect and avoid association with malicious nodes (i.e. jammers or black holes). Detailed numerical results highlight the usefulness of the proposed analysis, providing valuable insights on system design and parameterization towards enhanced network robustness.

The IEEE 802.16 standard provides a high degree of flexibility for setting up and operating wireless broadband networks in metropolitan environments. The standard supports numerous capabilities, including mesh topologies and multimedia communications. In this paper, we study these two features by investigating how efficiently an IEEE 802.16 mesh network can treat distributed multimedia traffic by providing differentiated quality of service (QoS). A key component of the system is the ldquoenhanced frame registry tree schedulerrdquo (E-FRTS) that provides QoS-aware resource allocation using a tree structure to prepare the creation of time frames and reduce processing requirements at the beginning of each frame. Simulation results show that distributed multimedia traffic can be efficiently supported in mesh 802.16 networks, provided efficient scheduling and a reasonable number of hops.