Analysis of LTE-A Heterogeneous Networks with SIR-based Cell Association and Stochastic Geometry

This paper provides an analytical framework to characterize the performance of Heterogeneous Networks (HetNets), where the positions of base stations and users are modeled by spatial Poisson Point Processes (stochastic geometry). We have been able to formally derive outage probability, rate coverage probability, and mean user bit-rate when a frequency reuse of $K$ and a novel prioritized SIR-based cell association scheme are applied. A simulation approach has been adopted in order to validate our analytical model; theoretical results are in good agreement with simulation ones. The results obtained highlight that the adopted cell association technique allows very low outage probability and the fulfillment of certain bit-rate requirements by means of adequate selection of reuse factor and micro cell density. This analytical model can be adopted by network operators to gain insights on cell planning. Finally, the performance of our SIR-based cell association scheme has been validated through comparisons with other schemes in literature.Comment: Paper accepted to appear on the Journal of Communication Networks (accepted on November 28, 2017); 15 page

Satellite-3G Hybrid Networks: Impact of ACM and ARQ on TCP Performance

The adoption of satellite systems in providing broadband transmissions to mobile users such as trains, buses and vans is expected to be an interesting solution. The scenariowe considered refers to a hybrid network architecture, where a geostationary satellite forward link and a terrestrial 3G return link are used in order to exploit both the high bandwidth of a satellite channel and the lower propagation delay of a terrestrial path. The resulting round-trip delay is much shorter than that one experienced by using both the forward and return link via satellite. This is particularly appealing for overcoming the TCP efficiency degradation in high delay-bandwidth product and error prone channels. In this hybrid scenario, we used simulation results to compare the goodput of four of the most popular TCP variants, in the presence of a GOOD-BAD satellite channel, as the one experienced by mobile users. We applied an AdaptiveCoding and Modulation (ACM) technique as well, and studied its impact on TCP efficiency, when used both alone and in cooperation with an Automatic Repeat reQuest (ARQ) scheme of the Selective Repeat (SR) type with low persistency. Results obtained indicate that this hybrid architecture is advantageous for TCP transmissions in terms of average goodput, and that ACM is effective only if it is jointly used with ARQ schemes

Satellite-3G Hybrid Networks: Impact of ACM and ARQ on TCP Performance

The adoption of satellite systems in providing broadband transmissions to mobile users such as trains, buses and vans is expected to be an interesting solution. The scenario we considered refers to a hybrid network architecture, where a geostationary satellite forward link and a terrestrial 3G return link are used in order to exploit both the high bandwidth of a satellite channel and the lower propagation delay of a terrestrial path. The resulting round-trip delay is much shorter than that one experienced by using both the forward and return link via satellite. This is particularly appealing for overcoming the TCP efficiency degradation in high delay-bandwidth product and error prone channels. In this hybrid scenario, we used simulation results to compare the goodput of four of the most popular TCP variants, in the presence of a GOOD-BAD satellite channel, as the one experienced by mobile users. We applied an Adaptive Coding and Modulation (ACM) technique as well, and studied its impact on TCP efficiency, when used both alone and in cooperation with an Automatic Repeat reQuest (ARQ) scheme of the Selective Repeat (SR) type with low persistency. Results obtained indicate that this hybrid architecture is advantageous for TCP transmissions in terms of average goodput, and that ACM is effective only if it is jointly used with ARQ schemes

Real-Time HAP-Assisted Vehicular Edge Computing for Rural Areas

Non-Terrestrial Networks (NTNs) are expected to be a key component of 6th generation (6G) networks to support broadband seamless Internet connectivity and expand the coverage even in rural and remote areas. In this context, High Altitude Platforms (HAPs) can act as edge servers to process computational tasks offloaded by energy-constrained terrestrial devices such as Internet of Things (IoT) sensors and ground vehicles (GVs). In this paper, we analyze the opportunity to support Vehicular Edge Computing (VEC) via HAP in a rural scenario where GVs can decide whether to process data onboard or offload them to a HAP. We characterize the system as a set of queues in which computational tasks arrive according to a Poisson arrival process. Then, we assess the optimal VEC offloading factor to maximize the probability of real-time service, given latency and computational capacity constraints

Satellite-5G integration: a network perspective

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

link adaptation in satellite lte networks

This paper investigates the impact of the Round Trip Propagation Delay (RTPD) in the satellite LTE air interface with the adoption of MIMO technology. The Satellite LTE air interface will provide global coverage and hence complement its terrestrial counterpart in the provision of LTE services to mobile users. A land mobile dual-polarized GEO satellite system has been considered for this work. The link adaption is an important module for the scheduling scheme and the satellite LTE network as a whole in order to make optimal scheduling decisions and effectively utilize the network resources respectively. However, the long RTPD experienced when Channel Quality Indicator (CQI) is reported from the User Equipment (UE) to the eNodeB via GEO satellite causes misalignment between the reported CQI at the eNodeB and the present CQI of the mobile user. The aim of this paper is to investigate the effect of the misalignment as a result of long RTPD through simulations and also investigate the effect of varying CQI reporting interval on the system performance of Satellite LTE network. The possibility of using a fixed CQI rather than an adaptive CQI is also investigated

BSM Integrated PEP with Cross-Layer Improvements

Abstract-The future development of broadband satellite systems providing services based on the Internet Protocol (IP) needs to be stimulated by means of common standards. This paper presents the ETSI BSM PEP terminal architecture and PEP usage scenarios. In addition this paper shows the benefits of cross-layer improvements, where the TCP traffic sent by STs through an NCC/Gateway that acts as a PEP-spoofer on ACKs going in the opposite direction