Abstract
IEEE 802.11 is currently one of the main wireless technologies enabling ubiquitous Internet access. With the growing demand for wireless Internet access and the limited 802.11 radio range, 802.11-based Wireless Mesh Networks have been proposed as a flexible and cost-effective solution to extend the radio coverage of existing network infrastructures. Many solutions have been proposed to create Wireless Mesh Networks automatically. However, they are either too complex or deal with multicast traffic inefficiently using pure flooding. We propose a simple and efficient solution, called WiFIX+, to forward multicast traffic over 802.11-based Wireless Mesh Networks. It is based on WiFIX, an existing solution targeted at unicast traffic and extends it with new mechanisms. WiFIX+ was implemented and evaluated in a laboratorial test-bed. The experimental results obtained show that it outperforms IEEE 802.11s, the reference solution for 802.11-based Wireless Mesh Networks, as far as data throughput, delay, and packet loss are concerned. © 2010 IEEE.

Abstract
This Special Issue originates from the international conference 2021 Joint EuCNC & 6G Summit (Joint European Conference on Networks and Communications and 6G Summit), which was held in June 2021 in virtual format. The Technical Programme Chairs of the conference selected the best papers and invited authors to submit an extended version of their paper by at least one-third of their length. Only the top ranked papers were invited to this Special Issue, in order to fulfil its purpose. The main target was to collect and present quality research contributions in the most recent activities related to technologies, systems and networks beyond 5G. Through this Special Issue, the state-of-the-art is presented and the new challenges highlighted, regarding the latest advances on systems and network perspectives that are already being positioned beyond 5G, bridging as well with the evolution of 5G, including applications and trials. Therefore, the motivation for this Special Issue is to present the latest and finest results on the evolution of research of mobile and wireless communications, coming, but not exclusively (since Joint EuCNC & 6G Summit is a conference open to the whole research community), from projects co-financed by the European Commission within its R&D programmes.

Abstract
The Internet is characterized by the coexistence of two Internet Protocol (IP) versions and multiple autoconfiguration mechanisms which are deployed targeting specific communication scenarios. This heterogeneity requires user pre-configurations, namely with respect to the proper autoconfiguration mechanism to be used at each time. On the other hand, future networks may imply that users own personal networks demanding self-configuration and self-management, and being part of very dynamic scenarios. In this paper we make a survey of the autoconfiguration mechanisms available for IP networks, and argue that a new solution is needed, so that the proper autoconfiguration mechanism can be selected automatically, dynamically and efficiently, and future communication paradigms can be properly addressed. Copyright 2005 ACM.

Abstract
Wireless Mesh Networks (WMNs), which feature infrastructureless broadband network configurations, are attracting attention as an elemental technology when it comes to the extension of current WLAN infrastructures. State of the art solutions addressing WMNs usually assume the use of omnidirectional antennas. In this paper we evaluate the performance improvements obtained when using directional antennas. By using simulations, we analyze the gains in terms of throughput, delay and fairness, considering a grid network topology used to extend an infrastructure network. Simulation results show that by changing the type of antenna in use from omnidirectional to directional, the average throughput of a WMN can increase about 56% and the average network delay can be reduced by approximately 40%, without compromising fairness. © 2010 IEEE.

Abstract
In the Next Generation Networks (NGNs) users will carry multiple devices forming cooperative networks known as Personal Area Networks (PANs). Some existing technologies enable this type of networks, such as Bluetooth or IEEE 802.15.4, but a unified framework capable of self-organizing them dynamically in a full heterogeneous environment populated by these and other technologies still has to be defined. Also, these networks are envisioned to be connecting dynamically to the Internet, and may use two IP versions and their autoconfiguration mechanisms. In this paper we propose a new framework, the Autoconfiguration and Self-management of Personal Area Networks (ASPAN), which enables the automatic and dynamic deployment of PANs in the heterogeneous environments envisioned for NGNs and handles the automatic and dynamic connection of a PAN to the global Internet. Copyright 2006 ACM.

Abstract
Communication networks have been developed based on two networking approaches: bridging and routing. The convergence to an all-Ethernet paradigm in Personal and Local Area Networks and the increasing heterogeneity found in these networks emphasizes the current and future applicability of bridging. When bridging is used, a single active spanning tree needs to be defined. A Minimum Routing Cost Tree is known to be the optimal spanning tree if the probability of communication between any pair of network nodes is the same. Given that its computation is a NP-hard problem, approximation algorithms have been proposed. We propose a new approximation Minimum Routing Cost Tree algorithm. Our algorithm has time complexity lower than the fastest known approximation algorithm and provides a spanning tree with the same routing cost in practice. In addition, it represents a better solution than the current spanning tree algorithm used in bridged networks.