Internet of Things (IoT) systems are becoming an interesting solution to be deployed in remote areas of the Earth with no terrestrial Internet connectivity and no energy supply. This paper investigates the cases where Low Earth Orbit (LEO) satellites are used to collect data from dispersed sensors with low density, thus supporting the so-called Internet of Remote Things (IoRT). This approach can be useful for monitoring the environment and smart agriculture on a large scale. In these circumstances, relatively cheap CubeSats systems can collect the sensor data transmitted by the ground IoT nodes. This work focuses on the feasibility of the link budget referring to LoRa radio technology for direct transmissions from ground nodes to LEO satellites. Since CubeSats have a very simple technology onboard, they do not use inter-satellite links. Therefore, a satellite collecting data from a ground node needs to store the data onboard until it reaches the visibility of a ground gateway station to forward these data onto the Internet. Focusing on this Store & Forward (S&F) approach, we have investigated the latency performance for the data delivery into the Internet considering both Kepler and the Swarm Technology CubeSat constellations and the impact of node location and minimum elevation angle allowed by the system.

This paper considers Low Power Wide Area Network (LPWAN) IoT devices deployed in rural areas without terrestrial Internet connectivity and local energy supply. These devices are equipped with sensors to continuously monitor ground conditions and deliver measurements to the Internet using the LoRa/LoRaWAN technology, exploiting the occasional connectivity to fixed-wing Unmanned Aerial Vehicles (UAVs). This work proposes an approach to coordinate the UAV pass with the transmissions of ground nodes for smart agriculture to allow scheduled access to the LoRa gateway onboard the UAV. A testbed has been developed to study the propagation in the LoRa ISM band at 868 MHz. Then, a waypoint-based UAV closed path is devised, where the waypoints are determined as the centroids of the k-means clustering scheme on IoT node locations. Based on the Matlab UAV simulator, we determine the UAV flight trajectory and identify the intervals during which each ground node can transmit to the UAV; these intervals are used to schedule the transmissions of these nodes. We evaluate the performance of this UAV access scheme in terms of different indicators related to outage events , packet collisions, and the risk that the visibility interval of the UAV is too short for a certain node to allow it to send data to the UAV. We investigate different tradeoffs, showing that using small Spreading Factor (SF) values and selecting the maximum possible UAV flight altitude is more convenient for achieving a high probability of collecting data from the nodes in one UAV flight cycle.

With the rapid rise in passenger demand and expanding flight routes, in-flight connectivity has become increasingly critical. Existing technologies—satellite communications with broad coverage but limited capacity, and ground-based networks offering high-speed, low-latency connections but constrained by geographic reach—each fall short of delivering seamless service independently. This paper introduces an innovative approach by integrating satellite and ground-based networks through a dynamic parameter and protocol-enhanced handover mechanism tailored for aeronautical communications in satellite-terrestrial integrated networks, and can be extended to Internet of Things scenarios such as disater response, remote sensing via unmaned aerial vehicle. Unlike conventional methods, our novel user-controlled location-based handover approach addresses the challenges of high aircraft-LEO satellite mobility and significant signaling latency by optimizing the handover decision process. This method reduces signaling overhead, improves target selection accuracy, and adapts dynamically to environmental variations, overcoming limitations posed by fluctuating satellite signal strength. Formulated as a multi-objective optimization problem, our approach minimizes handover interruption time while ensuring uninterrupted connectivity. Simulation results demonstrate that this approach lowers signaling overhead during handover requests and enhances connectivity throughout the flight, marking a novel step forward in aeronautical communication efficiency. Simulation results show the OLHO scheme achieving an 83.96% connection rate—higher than benchmarks—though at the cost of increased handover frequency, and 25% lower signaling overhead in SAGIN. This shows a clear trade-off between connection rate and handover intensity, where OLHO balances service continuity and stability via location-based handover triggers.

In this paper, we investigate Non-Terrestrial Network (NTN)-empowered Multi-access Edge Computing (MEC) systems for emerging applications like telemedicine, industrial automation, and augmented reality, which demand significant computational resources from User Equipments (UEs). To address these issues, we consider that UEs can either process tasks locally or offload them to edge servers deployed on Unmanned Aerial Vehicles (UAVs) and Low Earth Orbit (LEO) satellites. The efficacy of such systems crucially depends on formulating an efficient computation offloading policy. We propose a multi-agent distributed deep reinforcement learning (MADDRL) approach for computation offloading in NTN-empowered MEC systems. Our approach utilizes two distributed DRL frameworks: Centralized Training and Decentralized Execution (CTDE), where training occurs on a central controller, and Independent Learners (IL), where training is performed locally on the UEs. In both frameworks, policies are executed by UEs in a decentralized manner. Simulation results show that the CTDE framework reduces the average cost, defined as the weighted sum of delay and energy consumption experienced by the UEs, by 11%, 42%, and 66% compared to IL, local, and random policies, respectively.

Today's vehicles are expected to interact with each other to improve road safety and efficiency. We refer here to the LTE-V standard defined by 3GPP Release 14. In particular, we consider the platoon scenario where a vehicle, acting as a leader, coordinates the movement of a group of vehicles. LTE-V Mode 3 is assumed where the eNB has the control of the allocation of V2V transmission resources to the platoon. V2V communications adopt the underlay mode, reusing the resources of common cellular users. This paper provides an analytical model to determine the V2V link outage probability, the Cooperative Awareness Message (CAM) loss probability after a generic number of reattempts, and the mean number of transmission attempts to deliver the CAM message successfully, taking shadowing correlation effects into account. This model has been validated using simulations.

The expansion of the maritime industry with the increase of ship data traffic calls for the support of satellite communications not only for bandwidth-hungry applications for passengers and crew but also for Internet of Things applications. In this paper, we address the problem of efficiently managing the distribution of the vast amount of sensor data from ships to remote control centers and harbor authorities. An efficient solution to tackle this problem is adopting an Information-Centric Networking (ICN) approach. ICN is based here on Named Data Networking (NDN), which is one of the most efficient ICN approaches. We propose an efficient naming scheme for NDN, where the processing of local data from sensors allows improving the mean delay to deliver the sensor data. A simulation approach has allowed us to validate our proposed approach against the hierarchical naming scheme of NDN.

Device-to-Device (D2D) communications underlying a cellular network have been recognized as an important approach for performance improvement in 5G networks. In this paper, we refer to an LTE-A scenario where the underlay mode is adopted to allow D2D pairs to communicate directly by sharing sub-channels with Cellular Users (CUEs). Our aim is to propose heuristic resource allocation and pairing schemes to distribute radio resources among CUEs and D2Ds in a cell taking the interference because of pairing into account. In particular, we compare suitably-modified Proportional Fairness (PF) schemes with heuristic max-capacity approaches in terms of CUE and D2D capacity and fairness conditions. Extensive simulation runs have been carried out (Monte Carlo approach) and have allowed us to select a PF-based scheme and a technique combining Round-Robin with capacity maximization as two promising alternatives in order to assign resources to D2Ds and CUEs.

This paper deals with forward link scheduling at a terrestrial Gateway (GW) for a geostationary satellite system based on the DVB-S2/S2X standard. We consider the case of Time-Slicing (TS) that deserves particular attention for the current market of high-throughput low-cost user terminals. Two QoS traffic classes and related requirements have been envisaged that is real-time and non-real-time services. In this paper, a novel multi-stage GW scheduler architecture is investigated in order to support the TS option of DVB-S2/S2X. This scheduler takes several aspects into account, such as IP class of service, PHY-layer conditions, BBframe generation, and TS structure. Many scheduling schemes are compared for both real-time and non-real-time services in terms of different performance indexes related to the traffic management at the terrestrial GW. A simulator has been built modifying the SNS3 simulator developed in another project.

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.

This paper deals with the implementation of an online platform for Responsible Research and Innovation (RRI), which provides anticipatory and deliberative tools to address societal expectations with regard to resrarch and innovation and mobilises information technology tools for inclusive, responsive and sustainable research. In particular, we have developed a Forum, which is a Web-based application and service for stakeholders (members of the RRI community) to deliberate and discuss about RRI. Different interaction modalities are supported by the Forum, such as: `Caucus Process', Suggestion Board, Partnership Initiative, etc. A special attention is devoted to the Citizen Jury and Tacit Knowledge modules that represent innovative features of our Forum. The outcomes show that our online Forum represents an effective solution to address RRI issues by adopting e-Government and knowledge management approaches. This work was carried out as part of EU FP7 Responsibility project.

This paper proposes a quality of service (QoS) management framework for high throughput satellite (HTS) systems using extremely high frequency (EHF) frequency bands, which can achieve high capacity provided that feeder link outage events caused by severe weather conditions can be properly counteracted. To this regard, smart gateway diversity architectures implementing advanced gateway handover procedures are certainly attractive, although they can only partly mitigate the negative effects of adverse weather conditions in terms of packet losses, delays, and jitters, which significantly degrade the performance of delay-sensitive and delay-insensitive traffic flows. To cope with these technical challenges, we propose an incremental rerouting scheme to control congestion events because of capacity reduction during the transient phase, consisting of offloading high-priority QoS traffic flows from the affected gateway towards gateways operating in more favorable conditions. Moreover, we apply inter-flow network coding at the gateways to protect delay-insensitive flows from packet losses occurring during feeder link outage. Finally, extra capacity is reserved at the gateways to handle the additional traffic resulting from gateway handover. The theoretical analysis (validated by simulation campaigns) allowed characterizing network coding performance and confirming the potentialities of our QoS management framework for HTS systems.

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.

This paper explores the network design implications to be taken into account in Smart Gateway Diversity (SGD) satellite systems, where gateway outage events have to be counteracted by efficient handover procedures. In more detail, enabling high data-rate satellite systems in these conditions requires efficient coordination strategies between gateways, upstream routers and Network Control Centre (NCC) to precisely estimate the need of handover and to efficiently manage the satellite resources. To this regard, this paper adopts a simple channel estimation algorithm and applies network coding to cope with packet losses deriving from possible inaccuracies on the prediction of the handover time. The results obtained via simulation confirm the capabilities of network-coding-based approaches and pave the way for further studies in the area of network for SGD satellite systems.

This work aims at introducing two novel packet retransmission techniques for reliable multicast in the framework of Instantly Decodable Network Coding (IDNC). These methods are suitable for order- and delay-sensitive applications, where some information is of high importance for an earlier gain at the receiver's side. We introduce hence an Unequal Error Protection (UEP) scheme, showing by simulations that the Quality of Experience (QoE) for the end-users is improved even without complex encoding and decoding.

GEO satellite communication systems are an efficient approach for broadband Internet provision on high-speed trains, but some work is still needed to allow a seamless service. This paper deals with improving the TCP performance using vertical handovers (based on MIH) from the satellite to a terrestrial wireless segment (hybrid network) and viceversa to cover tunnels. We have shown that TCP goodput behavior and convergence time can be improved by means of suitable accelerated TCP versions or with cross-layer methods. This work has been carried out within the framework of ESA SatNEx III NoE (Contract RFQ/3-12859/09/NL/CLP).

The broadband satellite multimedia (BSM) architecture standardised by ETSI defines a satellite independent service access point (SI-SAP) interface layer that separates the satellite independent features of the upper layers from the satellite dependant features of the lower layers, and provides a mechanism to carry IP-based protocols over these satellite dependent lower layers. This enables interoperability at the IP layer between satellite systems of different physical and link layers technologies that fully comply with the SI-SAP concept. This study reviews past and current standardisation activities including the BSM quality of service (QoS) architecture, security architecture, network management that have been carried out by the ETSI Technical Committee-Satellite Earth Stations and Systems (TC-SES)/BSM working group and looking into the future to extend current SI-SAP functions that can enhance existing QoS provision and security management capabilities as well as proposing a mobility management architecture that complies with the IEEE 802.21 media independent handover framework to support BSM mobility and to allow integration of satellite networks with fixed and mobile network infrastructures. A service-based network management architecture is also proposed to allow management flexibility and integration of business and operation support functions, paving the way for satellite integration into the Internet of the future.

In this paper, we compare two multicast adaptive techniques for reliable data delivery in GEO satellite networks. Specifically, a channel-aware scheduling algorithm is compared with a multicast link adaptation technique, in the face of fluctuating channel conditions in downlink. The aim of the techniques is to maximise system throughput whilst increasing resource utilization. The scheduling technique is implemented within one forward bearer subtype, whereas the link adaptation mechanism considers transmission rates from a list of possible forward bearer subtypes. Simulation results are analysed and it is found that multicast link adaptation technique outperforms channel-aware scheduling algorithm, in terms of reduced session delay and retransmitted number of segments.

Satellite networks are an attractive solution to provide broadband communication services anytime, anywhere with quality of service support. The aim of this paper is to study the integration of GEO satellite networks, DVB-RCS- based, with WiFi networks. This is particularly important in emergency scenarios where reliable satellite networks could be integrated with WiFi systems for local mobility support. In this paper, a combined-dynamic resource management scheme, CRA & A/VBDC, is investigated for the satellite segment to support VoIP and FTP elephant connections. A corresponding QoS differentiation is considered in the WiFi segment, based on the IEEE 802.11e standard; in particular, a suitable traffic class mapping is proposed for an efficient interconnection of the DVB- RCS segment with the WiFi one. The obtained results prove the efficiency achieved by the proposed dynamic approach as the number of terminals increases, the good performance obtained with Scalable TCP and the importance of the proposed traffic mapping in the WiFi segment.

Satellite networks can provide the possibility to access communication services on wide areas of the earth; this characteristic coupled with the support of user mobility allows satellite networks having unique features well suited for different scenarios, like: land mobile, aeronautical, maritime, transports, rescue and disaster relief. Mobile satellite networks, however, entail crucial technological challenges, such as: link budget, antenna technologies for both the satellite and the mobile terminal, and efficient utilization of the radio spectrum. This paper investigates these aspects and provides an analytical framework that can be used to evaluate the characteristics of satellite networks in the design phase as well as for their operational phase. In particular, quantitative comparisons are presented here for different systems in terms of supported user density, bandwidth efficiency, and mobility aspects.

Terrestrial and satellite networks have dominated the telecommunications arena for years. In parallel with these two well-established technologies, a new alternative based on platforms located in the stratosphere, termed high altitude platforms (HAP's), has gained considerable interest in the past few years. In this paper, we consider an integrated HAP-satellite architecture and propose a reliable multicast protocol that capitalizes upon the HAP-layer to perform local retransmissions. Our protocol relies on a progressive packet-level forward error correction (FEC) scheme. The performance of this multicast protocol has been supported thorough the comparison with a theoretical bound in the literature.

The TCP efficiency degradation in high delay- bandwidth product and error-prone channels is a well-known problem. To reduce this degradation, we utilized a hybrid wireless network architecture, where a geostationary bent-pipe satellite channel is used for forward high bit-rate transmissions, while the return link is realized through a terrestrial 3G segment. The performance of four of the most popular TCP versions are tested and compared via simulations in terms of goodput. Our aim is choosing which version performs better by using an Adaptive Coding and Modulation (ACM) technique, both alone and together with an Automatic Repeat reQuest (ARQ) scheme of the Selective Repeat (SR) type. ARQ is used with and without transmit and receive timeouts. The obtained results show that such a hybrid architecture is advantageous for TCP transmissions in terms of average goodput, and that ACM is effective only if used together with ARQ schemes.

This paper proposes a novel packet scheduler for the high speed downlink packet access (HSDPA) air interface. In designing the scheduler we take in account two different user types and two distinct traffic classes. Our aim is to differentiate the quality of service and at the same time to achieve a high throughput and a fair allocation of resources among users. The performance of the proposed scheme is compared through simulations with other scheduling techniques (e.g., maximum SIR). This work is the outcome of a joint activity between the University of Siena and CUNY.

This paper deals with modifications to the current IEEE 802.11b distributed coordination function (DCF) protocol of the medium access control (MAC) to support service differentiation between premium and regular users. A volume-based revenue model has been integrated with our simulation tool to understand clearly the impact of different traffic classes and user types. This work has been carried out under a joint cooperation between the University of Siena and CUNY.

This paper deals with the proposal of a novel resource management scheme for efficient downlink transmissions in broadband wireless systems with synchronous base stations. Such technique is able to vary dynamically the transmission characteristics and the resource allocation in order to guarantee suitable quality of service levels for both high-quality video streaming traffic and heavy Web downloading one. Our strategy, named dynamic-priority and mode selection (D-PMS), allows superior performance with respect to a previously proposed solution in the literature.

Abstract The unique capabilities of new cellular systems are expected to provide users with integrated multimedia services. Since the air interface still represents the system bottleneck, this paper proposes novel scheduling techniques to integrate efficiently the support of real‐time traffic (i.e. voice and video) and data bursty traffic under quality of service (QoS) guarantees. Prioritization among traffic classes is adopted and a polling service discipline is employed within a class, where the permission rights of each traffic source are determined on the basis of token bucket regulators. Two polling‐based approaches are compared to serve the sources of a class: (i) when a source is enabled to transmit, a burst of packets is sent at once; (ii) within the time interval destined to a traffic class, a cyclic service of the sources is allowed on a packet basis. With realistic assumptions on both radio channel conditions and protocol signaling overhead, this paper compares these two different approaches and the dynamic slot assignment++ (DSA++) scheme appeared in the literature. The obtained results highlight that our second scheme (case ii) allows increasing the number of supported video traffic sources of many units with respect to DSA++. Finally, an analytical approach has been proposed for our second polling scheme. Copyright © 2004 John Wiley & Sons, Ltd.

This paper deals with an optimized packet access scheme depending on traffic load conditions that is able to support efficiently three traffic classes (voice, Web interactive and short messages) in non-geostationary mobile satellite systems. We adopt the equilibrium point analysis in order to study the stability of our scheme. This allows identifying optimal values for the protocol control parameters. Extensive comparisons have been performed with other techniques in the literature showing the good results achieved by our protocol.

This paper compares two possible scenarios for mobile Internet surfing according to the Personalised Access to Local Information and services for tOurists (PALIO) Project (IST-1999-20656). In particular, we consider WAP phones with Short Message Service (SMS) and Personal Digital Assistants (PDA) with General Packet Radio Service (GPRS). Suitable round robin scheduling schemes are analyzed for downlink transmissions. Part of this work has been also contributed to the COST 273 Project.

Mobile satellite systems (MSSs) are expected to play a significant role in providing users with communication services worldwide. In such a context, low Earth orbit (LEO) satellite constellations seem to be a good solution to attain a global coverage and to allow the use of low-power lightweight mobile terminals. This paper analyzes the performance of a novel medium access control (MAC) scheme suitable for applications in LEO-MSSs, named packet reservation multiple access with hindering states (PRMA-HS), that has been derived by proper modifications of the well-known PRMA protocol. We envisage a mixed traffic with voice sources and data sources with different quality of service (QoS) requirements. The good behavior of the proposed PRMA-HS scheme is validated by extensive comparisons with the classical PRMA protocol. Finally, it is shown that PRMA-HS efficiently supports integrated voice and data traffic in LEO-MSSs.

A novel medium access control (MAC) protocol, named dynamic resource assignment multiple access enhanced version (DRAMA+), is proposed for low Earth orbit-mobile satellite systems (LEO-MSSs). It is based on a time division multiple access air interface and utilizes access slots distinct from information slots. The DRAMA+ scheme realizes an efficient access phase and manages transmission requests with an on board scheduler. On the basis of suitable models for both isochronous voice sources with activity detection and data bursty sources, we have shown that DRAMA+ outperforms other protocols in the literature.

This paper, based on the PALIO project, deals with an information tourist service accessible through mobile phones by means of the Wireless Application Protocol (WAP). We have considered a Global System for Mobile communications (GSM) network where the WAP traffic is transported by the Short Message Service (SMS) on a logical channel that also conveys signaling messages. Suitable models have been proposed for both WAP and signaling traffic. An analytical approach (validated by simulations) has been developed to evaluate the mean delay to browse a WAP page.

This paper envisages a cellular system based on code-division multiple access and investigates the performance of a strength-based closed-loop power control (CLPC) scheme on the basis of different parameters, such as the number of bits of the power command, the quantization step size, and the user speed. On the basis of a log-linear CLPC model, an analytical approach has been developed that has allowed to determine the optimum quantization step size to be used for each value of the number of power command bits. Simulation results have permitted to support the analytical framework developed in this paper.

Abstract This paper, based on the PALIO Project within the fifth Research Framework of the European Commission, deals with an information tourist service accessible through mobile phones by means of theWireless Application Protocol(WAP). We have considered aGlobal System for Mobile communications(GSM) network where the WAP traffic is transported by theShort Message Service(SMS) on a logical channel that also conveys signaling messages. Suitable models have been considered for both WAP browsing traffic and signaling traffic. We have proposed a theoretical approach to evaluate the mean delay to browse a WAP page taking into account the impact of the signaling load. Analytical predictions have been validated through comparisons with simulation results. Moreover, we have also considered a specificQuality of Service(QoS) requirement in terms of the maximum deck transmission delay that is guaranteed in 95 per cent of cases. Consequently, it has been possible to evaluate the number of WAP users that can be supported per cell. The study carried out in this paper permits to prove the feasibility for the envisaged mobile service based on WAP and it also allows dimensioning WAP pages so that each user experiences reasonable browsing delays. Copyright © 2001 John Wiley & Sons, Ltd.

Future wireless systems will allow the mobile access to multimedia services. This paper proposes a medium access control (MAC) protocol that permits an efficient integration of real time-variable bit rate (rt-VBR) traffic and bursty available bit rate (ABR) traffic. This scheme, named minislotted-dynamic resource assignment (M-DRA), provides rt-VBR sources with a quality of service independent of the ABR traffic load. The M-DRA scheme effectiveness has been validated by comparisons with other protocols.

This paper proposes an analytical study which aims at evaluating the received power statistics in DS-CDMA cellular systems which use a closed-loop power control scheme to compensate for fast multipath fading. The effects of a limited transmission power at the mobile terminals have been also investigated. This study is based on a first order Taylor expansion of the fast fading fluctuations. The accuracy of the obtained results has been verified through computer simulations. Classical frequency-selective channel models have been taken into account which involve the use of a diversity RAKE receiver at the base station. Finally, the system capacity is evaluated under different environmental conditions.

This paper envisages data transmissions in a low-mobility wireless local area network based on a DS-CDMA air interface. A Rayleigh fading channel and suitable Internet-like traffic model have been envisaged to study the impact of the closed-loop power control on an adaptive coding scheme. The following quality of service (QoS) parameters have been considered in this study: the mean datagram transmission delay and the mean transmission energy per useful bit. We have obtained that our proposed adaptive coding scheme permits one to avoid the use of closed-loop fast power control. Such choice permits one to improve both previous QoS parameters, so allowing an efficient management of radio resources.

This paper deals with the performance evaluation of various resource management strategies that are suitable for low Earth orbit mobile satellite systems (LEO-MSSs). A user mobility model has been proposed and its statistical parameters have been derived. Both fixed channel allocation (FCA) and dynamic channel allocation (DCA) techniques have been considered. Moreover, in order to reduce the handover failure probability, we have assumed that interbeam handover requests which do not immediately obtain service can be queued. In particular, two different queuing disciplines have been compared: (a) the first input first output (FIFO) scheme and (b) a new technique called last useful instant (LUI) which is based on the knowledge of the maximum time within which the handover procedure must be accomplished. Implementation aspects for the LUI technique in a LEO-MSS have been discussed also in comparison with the measurement-based priority scheme (MBPS), previously proposed in the literature on this subject. The efficiency of the LUI queuing scheme as regards the FIFO technique has been investigated by simulations for both DCA and FCA techniques. An analytical approach has been also presented in order to allow the performance evaluation of the FCA scheme with different handover queuing disciplines.

Efficient dynamic channel allocation techniques with handover queuing suitable for applications in mobile satellite cellular networks, are discussed. The channel assignment on demand is performed on the basis of the evaluation of a suitable cost function. Geostationary and low Earth orbit (LEO) satellites have been considered. In order to highlight the better performance of the dynamic techniques proposed, a performance comparison with a classical fixed channel allocation (FCA) has been carried out, as regards the probability that a newly arriving call is not completely served. It has also been shown that a higher traffic density, with respect to GEO systems, is manageable by means of LEO satellites.>