Massimo Condoluci

LTE for vehicular networking: a survey

A wide variety of applications for road safety and traffic efficiency are intended to answer the urgent call for smarter, greener, and safer mobility. Although IEEE 802.11p is considered the de facto standard for on-the-road communications, stakeholders have recently started to investigate the usability of LTE to support vehicular applications. In this article, related work and running standardization activities are scanned and critically discussed; strengths and weaknesses of LTE as an enabling technology for vehicular communications are analyzed; and open issues and critical design choices are highlighted to serve as guidelines for future research in this hot topic.

Toward 5G densenets: architectural advances for effective machine-type communications over femtocells

Ubiquitous, reliable and low-latency machine-type communication, MTC, systems are considered to be value-adds of emerging 5G cellular networks. To meet the technical and economical requirements for exponentially growing MTC traffic, we advocate the use of small cells to handle the massive and dense MTC rollout. We introduce a novel 3GPP-compliant architecture that absorbs the MTC traffic via home evolved NodeBs, allowing us to significantly reduce congestion and overloading of radio access and core networks. A major design challenge has been to deal with the interference to human-type traffic and the large degree of freedom of the system, due to the unplanned deployments of small cells and the enormous amount of MTC devices. Simulation results in terms of MTC access delay, energy consumption, and delivery rate corroborate the superiority of the proposed working architecture.

Adaptive Resource Allocation to Multicast Services in LTE Systems

This paper addresses the design of an adaptive resource allocation policy for the efficient delivery of multicast services in Long Term Evolution (LTE) systems. The proposed approach overcomes the intrinsic inefficiencies of Conventional Multicast Scheme (CMS) related to the different channel quality experienced by the involved users. The basic idea is to split any multicast group into subgroups and apply subgroup-based adaptive modulation and coding schemes, which enable a more efficient exploitation of multi-user diversity. The distribution of users into subgroups is determined by the solution of an optimization problem, aiming to improve the network throughput while guaranteeing fairness among multicast members.

Single Frequency-Based Device-to-Device-Enhanced Video Delivery for Evolved Multimedia Broadcast and Multicast Services

Despite of the undisputed benefits of the long term evolution-advanced (LTE-A) networks, offering support for group-oriented services challenges the evolved multimedia broadcast multicast services (eMBMS) design in LTE-A. This is especially important when delivering video content with high bitrate requirements. The conventional multicast scheme (CMS) is proposed as a radio resource allocation solution for eMBMS to serve all multicast group members with the data rate supported by the receiver with the worst channel conditions. In this paper, we propose a novel radio resource management approach, the device-to-device (D2D)-enhanced CMS with single frequency (D2D-SF). This proposal extends the CMS with additional D2D communications in order to increase the aggregate data rate of the cell, while also maintaining the typical CMS short-term fairness. D2D-SF makes use of one or more mobile subscriber devices as forwarding devices (FD) to retransmit the data received from the base station (BS) over direct local links to other members of the multicast group. The proposed solution supports both high-rate modulation and coding schemes on the downlink from BS to FDs, and reaches cell-edge devices (hence, experiencing worse channel conditions) through high-performing D2D links (improving this experience). Testing shows how the single frequency-based D2D CMS paradigm proposed, complemented by two novel strategies for selecting FDs, achieves significant enhancements of the overall performance when delivering video content compared to both the state-of-the-art multicast solutions and novel solutions that do not employ a single-frequency paradigm.

A Low-Complexity Resource Allocation Algorithm for Multicast Service Delivery in OFDMA Networks

Allocating and managing radio resources to multicast transmissions in orthogonal frequency-division multiple access (OFDMA) systems is the challenging research issue addressed by this paper. A subgrouping technique, which divides the subscribers into subgroups according to the experienced channel quality, is considered to overcome the throughput limitations of conventional multicast data delivery schemes. A low complexity algorithm, designed to work with different resource allocation strategies, is also proposed to reduce the computational complexity of the subgroup formation problem. Simulation results, carried out by considering the Long Term Evolution system based on OFDMA, testify the effectiveness of the proposed solution, which achieves a near-optimal performance with a limited computational load for the system.

Enabling the IoT Machine Age With 5G: Machine-Type Multicast Services for Innovative Real-Time Applications

The Internet of Things (IoT) will shortly be undergoing a major transformation from a sensor-driven paradigm to one that is heavily complemented by actuators, drones, and robots. The real-time situational awareness of such active systems requires sensed data to be transmitted in the uplink to edge-cloud, processed, and control instructions transmitted in the downlink. Since many of these applications will be mission critical, the most suitable connectivity family will be cellular due to the availability of licensed spectrum able to protect the offered communications service. However, while much focus in the past was on the uplink of machine-type communications, little attention has been paid to the end-to-end reliability, latency, and energy consumption comprising both up and downlinks. To address this gap, in this paper, we focus on the definition, design, and analysis of machine-type multicast service (MtMS). We discuss the different procedures that need to be redesigned for MtMS and we derive the most appropriate design drivers by analyzing different performance indicators, such as scalability, reliability, latency, and energy consumption. We also discuss the open issues to be considered in future research aimed at enhancing the capabilities of MtMS to support a wide variety of 5G IoT use cases.

Wi-Fi cooperation or D2D-based multicast content distribution in LTE-A: A comparative analysis

Exploiting short-range technologies like Wi-Fi for achieving benefits in terms of throughput and energy consumption, has been among the first proposals to enhance the data transfer performance in cellular environments. Today, with the advent of high performing Long Term Evolution-Advanced (LTE-A) systems, Device-to-Device (D2D) communication, supporting proximity based services in both licensed and unlicensed bands, has recently come into play. In the context of LTE-A systems, this paper proposes different solutions with reference to a “multicast content distribution service”. A comparative analysis between Wi-Fi cooperation and the proposed D2D-based solutions is presented and their pros and cons will be illustrated. The cases where the early conceived wireless cooperation paradigm may still be of interest will be highlighted, while service delivery enhancements obtained with D2D-based solutions will be evaluated. In particular, when compared to standard multicast solutions, content delivery time and energy savings up to respectively 40% and 80% can be obtained.

Efficient Frequency Domain Packet scheduler for Point-to-Multipoint transmissions in LTE networks

Long Term Evolution (LTE) is the emerging 4G wireless technology developed to provide high quality services in mobile environments. It is foreseen that multimedia services and mobile TV will assume an important role for the LTE proliferation in mobile market. However, several issues are still open and meaningful improvements have to be introduced for managing physical resources when group-oriented services should be supplied. To this end, we propose a Frequency Domain Packet Scheduling (FDPS) algorithm for efficient radio resource management of Multimedia Broadcast/Multicast Services (MBMS) in LTE networks. The proposed scheduler exploits an optimization process to organize multicast subscribers in subgroups according to channel quality feedbacks provided by users. Optimization is driven by the aim of minimizing the “user dissatisfaction” with a consequent improvement in the network capacity. The effectiveness of the proposed scheduling algorithm is evaluated through simulation; obtained results demonstrate significant improvement in the multicast traffic performance.

When D2D communication improves group oriented services in beyond 4G networks

The design of effective radio resource management policies for group-oriented services in beyond-4G networks is attracting the interest of the research community. Along this line, this paper analyzes some novel approaches that take advantages of the Device to Device (D2D) communication paradigm with the aim of improving the session quality experienced by mobile users in terms of delay and energy consumption. The basic idea is to enable receivers with a bad cellular link from the evolved Node B (eNodeB) to receive the multicast service through another mobile device located in proximity over a direct link. Two schemes are proposed that exploit different radio technologies to enable nearby multicast subscribers to establish direct local links, either Long Term Evolution-Advanced (LTE-A) or Wi-Fi Direct. The effectiveness of the proposed solutions is demonstrated through a comprehensive simulative analysis and compared with traditional techniques that only exploit point-to-multipoint communication from the eNodeB to all the group members not taking advantages of the multi-user diversity or alternative network technologies to serve the multicast users.

Multicast service delivery solutions in LTE-Advanced systems

Multicast services over Long Term Evolution (LTE) have recently attracted the interest of the research community. Particular attention has been put on handling fairness requirements of multicast users and experienced channel quality. Conventional Multicast Scheme (CMS), Opportunistic Multicast Scheme (OMS), and multicast subgroup formation are the principal policies adopted to address this research issue. Little attention has been given so far to multicarrier systems like LTE-Advanced although the need for solutions appropriate to this system is strongly felt. In this paper we design radio resource management policies for the efficient delivery of multicast services in multicarrier LTE-Advanced systems and show how the relation between fairness and system efficiency can be controlled. Concerning the system resource management, game theoretic bargaining solutions are considered to best model fairness and efficiency (expressed in terms of throughput).