Van Anh Le

Bio: Van Anh Le is an academic researcher from University of Siena. The author has contributed to research in topics: Linear network coding & Quality of service. The author has an hindex of 7, co-authored 12 publications receiving 105 citations.

Iterative Multi-Level Soft Frequency Reuse With Load Balancing for Heterogeneous LTE-A Systems

Abstract: This paper deals with the planning of two-layer long-term evolution-advanced cellular systems, taking both the co-tier and cross-tier interference into account. In particular, we propose the novel multi-level soft frequency reuse (MSFR) scheme, where the users in three different regions of a macro/micro cell adopt distinct frequency segments and different transmission power levels. The optimization of power control parameters and cell association with MSFR results in a non-convex problem. We present the iterative-MSFR (I-MSFR) scheme, where the main optimization problem is divided into two sub-problems that can be subsequently solved by means of classical optimization methods. Finally, we propose two simplified schemes that achieve a comparable performance as I-MSFR in terms of utility, cell capacity, and outage conditions. I-MSFR and the simplified schemes have shown better performance than other schemes in the literature.

Soft frequency reuse schemes for heterogeneous LTE systems

Abstract: With the increasing demand of mobile data traffic, cellular networks are evolving towards heterogeneous systems involving cells of different sizes (e.g., pico, micro, and macro cells). The presence of small cells is causing new interference issues that require the introduction of frequency reuse techniques suitable to manage both co-tier and cross-tier interference. In this paper, we propose a novel Soft Frequency Reuse (SFR) scheme for LTE-A, based on three frequency segments (named Three-Band Improved SFR, 3B-ISFR) where the Frequency Reuse Pattern (FRP) allocation scheme for micro cells is centralized at the level of each macro cell. This scheme is based on the exchange of measurements made by the micro cells with their macro cell (cognitive-assisted approach) and includes an intra-cell offloading algorithm to balance the load between cell-center and cell-edge of each micro/macro cell. The goodness of 3B-ISFR has been proved by means of performance comparisons with other schemes in the literature in terms of outage probability and average cell capacity.

Analysis of a Packet-Level Block Coding Approach for Terrestrial-Satellite Mobile Systems

Abstract: The high data-rate of terminals together with the demand for anywhere-anytime user connectivity makes the simultaneous use of terrestrial and satellite infrastructures a necessity in mobile scenarios. To achieve a reliable and timely distribution of contents, there are important technical challenges concerning the implementation of multipath communication protocols and robust recovery mechanisms to cope with the signal degradation because of the effects of the mobile fading channel. In this respect, this paper proposes a new technique called path-based network coding to jointly exploit the availability of multiple paths and network coding to maximize the system transmission control protocol (TCP) goodput. An analytical approach allowing a formal optimization based on approximate derivations is proposed, which proves to be in good agreement with simulation results and a more accurate optimization method based on a genetic algorithm.

Resource Management and Cell Planning in LTE Systems

Abstract: Future 4G cellular systems will address the need for capacity increase for the support of diverse services. It is therefore of fundamental importance to design innovative 4G cellular systems able to support the increase in the traffic demand. This Chapter deals with LTE systems and the design of a new reuse scheme, called Soft Frequency Reuse (SFR), that is able to increase the cell capacity that is studied, considering the impact of different scheduling schemes and of different user mobility patterns. A consistent SFR scenario has been implemented in both Ns-3 and OMNeT++ environments. An analytical approach is proposed to evaluate the cell capacity with SFR that has been validated by means of Ns-3 simulations. Finally, OMNeT++ simulations have permitted to highlight the significant impact of the scheduling scheme and user mobility on cell capacity; different mobility patterns have been taken into account.

Network coding and MPTCP in satellite networks

Abstract: Satellite networks are expected to support multimedia traffic flows, offering high capacity with QoS guarantees. This paper deals with Multipath-TCP (MPTCP), which exploits multiple TCP connections using different paths in order to improve user’s throughput. In this study, MPTCP is combined with network coding to protect TCP transmissions from packet losses caused by ON/OFF channels in mobile satellite systems. A novel scheme, named Path-Based Network Coding for MPTCP (PBNC-MPTCP), has been proposed that applies Pseudo Random Network Coding (PRNC) to sub-flows, where the encoded packets of a block are sent on different paths in order to exploit path diversity. We have evaluated the PBNCMPTCP performance by means of Ns-2 simulations, showing that PBNC-MPTCP outperforms other schemes in the literature that combine MPTCP with network coding.

Satellite-5G Integration: A Network Perspective

Abstract: Future 5G mobile communication systems are expected to integrate different radio access technologies, including the satellite component. Within the 5G framework, the terrestrial services can be augmented with the development of HTS systems and new mega-constellations meeting 5G requirements, such as high bandwidth, low latency, and increased coverage including rural areas, air, and seas. This article provides an overview of the current 5G initiatives and projects followed by a proposed architecture for 5G satellite networks where the SDN/NFV approach facilitates the integration with the 5G terrestrial system. In addition, a novel technique based on network coding is analyzed for the joint exploitation of multiple paths in such an integrated satellite-terrestrial system. For TCP-based applications, an analytical model is presented to achieve an optimal traffic split between terrestrial and satellite paths and optimal redundancy levels.

Non-terrestrial networks in 5G & beyond: A survey

Abstract: Fifth-generation (5G) telecommunication systems are expected to meet the world market demands of accessing and delivering services anywhere and anytime. The Non-Terrestrial Network (NTN) systems are able to satisfy the requests of anywhere and anytime connections by offering wide-area coverage and ensuring service availability, continuity, and scalability. In this work, we review the 3GPP NTN features and their potential for satisfying the user expectations in 5G & beyond networks. The state of the art, current 3GPP research activities, and open issues are summarized to highlight the importance of NTN over the wireless communication landscape. Future research directions are also identified to assess the role of NTN in 5G and beyond systems.

Convergence of Satellite and Terrestrial Networks: A Comprehensive Survey

Abstract: The explosive growth of various services boosts the innovation and development in terrestrial communication systems for the implementation of the next generation mobile communication networks. However, simply utilizing limited resources in terrestrial communication networks is difficult to support the massive quality of service (QoS) aware requirements and it is hard to guarantee seamless coverage in far remote regions. Leveraging the intrinsic merits of high altitude and the ability of multicasting or broadcasting, satellite communication systems provide an opportunity for novel mobile communication networks with its tight interaction and complementary characteristics to traditional terrestrial networks. It is believed that the convergence of satellite and terrestrial networks can solve the problems existing in current mobile communication systems and make a profound effect on global information dissemination. In this paper, we make a comprehensive survey on the convergence of satellite and terrestrial networks. First, motivations and requirements of satellite-terrestrial network convergence are identified. Then, we summarize related architectures of existing literature, classify the taxonomy of researches on satellite-terrestrial networks, and present the performance evaluation works in different satellite-terrestrial networks. After that, the state-of-the-art of standardization, projects and the key application areas of satellite-terrestrial networks are also reviewed. Finally, we conclude the survey by highlighting the open issues and future directions.

5G Embraces Satellites for 6G Ubiquitous IoT: Basic Models for Integrated Satellite Terrestrial Networks

Abstract: Terrestrial communication networks mainly focus on users in urban areas but have poor coverage performance in harsh environments, such as mountains, deserts, and oceans. Satellites can be exploited to extend the coverage of terrestrial fifth-generation networks. However, satellites are restricted by their high latency and relatively low data rate. Consequently, the integration of terrestrial and satellite components has been widely studied to take advantage of both sides and enable the seamless broadband coverage. Due to the significant differences between satellite communications (SatComs) and terrestrial communications (TerComs) in terms of channel fading, transmission delay, mobility, and coverage performance, the establishment of an efficient hybrid satellite–terrestrial network (HSTN) still faces many challenges. In general, it is difficult to decompose an HSTN into a sum of separate satellite and terrestrial links due to the complicated coupling relationships therein. To uncover the complete picture of HSTNs, we regard the HSTN as a combination of basic cooperative models that contain the main traits of satellite–terrestrial integration but are much simpler and thus more tractable than the large-scale heterogeneous HSTNs. In particular, we present three basic cooperative models, i.e., model ${X}$ , model ${L}$ , and model ${V}$ , and provide a survey of the state-of-the-art technologies for each of them. We discuss future research directions toward establishing a cell-free, hierarchical, decoupled HSTN. We also outline open issues to envision an agile, smart, and secure HSTN for the sixth-generation ubiquitous Internet of Things.