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The Stream Control Transmission Protocol (SCTP) is a relatively new transport protocol. It has several underlying mechanisms that are similar to the Transmission Control Protocol (TCP), as well as several improvements that are important in certain classes of applications. The timeout scheme of SCTP, however, is almost identical to that used in TCP. With dynamics of today's Internet, that timeout scheme...
In this paper, we introduce a novel multiple access scheme for aerial sensor networks employing adaptive antenna arrays with spatial reuse. Spatial reuse has been adopted to enable simultaneous data transmission among unmanned aerial vehicles in a context of spatial diversity. This work introduces two types of UAV: a single main actor UAV and multiple actor UAVs. Since these UAVs cooperatively perform...
Virtual Private LAN Services (VPLS) is a widely utilized Layer 2 (L2) Virtual Private Network (VPN) architecture in industrial networks. In the last few years, VPLS networks gained an immense popularity as an ideal network architecture to interconnect industrial legacy SCADA (Supervisory Control and Data Acquisition) and process control devices over a shared network. However, legacy VPLS architectures...
Access reservation based on slotted ALOHA is commonly used in wireless cellular access. In this paper we investigate its enhancement based on the use of physical-layer network coding and signature coding, whose main feature is enabling simultaneous resolution of up to K users contending for access, where K ≥ 1. We optimise the slot access probability such that the expected throughput is maximised...
This paper focuses on the beneficial effects brought by the presence of multiple receivers to a slotted Aloha scheme. Starting from an analytical angle, we review and compare some recent results that characterize the throughput of such systems under different channel models, based on the assumption that incoming powers at receivers follow an i.i.d. distribution. While practical in some scenarios,...
This paper develops a model evaluating the impact of mobility in heterogeneous wireless networks by the way of analytical expressions of the spatio-temporal evolution of QoS indicators. Such formulas are obtained by introducing a multiuser averaged mobility pattern named density of users. Among the set of densities, we use a Gaussian form of this quantity, which results from a modeling method based...
Interference due to multi-channel CR hidden terminals and edge PU receivers at link level has direct impact on performance of CR-MAC protocol. State-of-the-art research in CR-MAC propose sequential, cluster-CCC coverage for In-band and global CCC coverage for out-of-band spectrum to avoid primary (PU) and secondary (CR) hidden terminals. But, imperfect node synchronization due to per hop and group...
Dense carrier sensing wireless networks are important scenarios to enable ubiquitous mobile Internet access. In this work, we study user experience from the end-to-end performance of dense p-persistent CSMA networks that suffers from operation interference among many non-coordinated APs. Results show that in dense networks, the effective coverage of APs shrinks and most STAs don't receive satisfactory...
Video streaming is the most popular application in today's mobile Internet and its growing demands and popularity put more and more load on cellular networks. In a recent trend to mitigate the cellular load, followed by many providers, users are offered to offload mobile connections to WiFi hotspots, which are predominately deployed in urban environments. In this work, we conduct a simulative performance...
To meet the challenge of the ever-growing traffic volume in current wireless communications, ultra-dense network (UDN) deployment with high system capacity has attracted wide attention in recent years. However, existing researches on UDN mainly focus on system throughput while ignore energy efficiency (EE). Therefore, we will analyze the UDN performance including not only system throughput but also...
Cognitive Radio (CR) with the capability of discovering the unused spectrum promises higher spectrum efficiency - a pressing requirement for 5G networks. However, CR owes this capability to power-hungry tasks, most particularly to spectrum sensing. Given that advances in battery capacity has a slower pace compared to advances in device capabilities and traffic growth, it is paramount to develop energy-efficient...
In this paper, we propose an energy efficient cross-layer design framework for transmitting Markov modulated Poisson process (MMPP) traffic over Nakagami-m fading channel with delay demands. The adaptive modulation and coding (AMC) is used at physical layer. We first investigate the stationary distribution of this system. With the stationary distribution and the AMC transmission mode, we derive the...
LTE in unlicensed bands (LTE-U) holds the promise of alleviating the licensed spectra scarcity and enhancing capacity by utilizing the unlicensed spectra. However, once LTE-U accesses an unlicensed band, there is almost no any opportunity for unlicensed systems (e.g. 802.11 WLAN) with inferior control abilities and CSMA/CA, to access that any more. In order to solve this unfair coexistence problem,...
LTE-A as a cellular technology has gained tremendous importance in recent years due to its high data-rates and improved data access for mobile devices. Recently, utilizing the unlicensed band as a supplementary band for LTE-A is being considered to expand the capacity of mobile systems. License-assisted access using LTE (LAA-LTE) will thus operate in the unlicensed band, and will operate in a spectrum...
ALOHA-type protocols became a popular solution for distributed and uncoordinated multiple random access in wireless networks. However, such distributed operation of the Medium Access Control (MAC) layer leads to sub-optimal utilization of the shared channel. One of the reasons is the occurrence of collisions when more than one packet is transmitted at the same time. These packets cannot be decoded...
In this paper, we consider the problem of resource allocation in the context of cognitive Satellite Communications (SatCom). In particular, we focus on the cognitive downlink access by Geostationary (GEO) Fixed Satellite Service (FSS) terminals in the band 17.7–19.7 GHz, where the incumbent users are Fixed-Service (FS) microwave links. Assuming a multiple Low Noise Block Converter (LNB) satellite...
In order to circumvent the throughput limitation imposed on visible light communication (VLC) systems by the limited LED bandwidth, optical orthogonal frequency division multiplexing (OFDM) with non-uniform bit-loading is studied in this paper. By using lower order modulation on subcarriers that suffer the most distortion, we show that it is possible to establish a high throughput and reliable OFDM...
AsWireless Local Area Networks (WLANs) become denser and denser recently, the contention-based MAC protocol such as the IEEE 802.11 DCF, the de facto standard for the WLAN, should be modified to handle such dense WLANs. To this end, we consider a recently proposed novel MAC protocol called the Renewal Access Protocol (RAP) in this paper. With the RAP, we consider two strategies for resolving collisions...
We consider new Dynamic Network Architecture (DNA) which provides significant soft capacity in the network enabling a wide range of adaptations to traffic demand variations without any change in the fixed network infrastructure. To maximize the system throughput we propose a new second order cone programming (SOCP) based algorithm to optimize jointly the access point (AP) selection and the downlink...
In this paper we propose a spectrum aggregation-based cooperative routing protocol, termed as SACRP, for CRAHNs. The primary objective of SACRP is to improve throughput and reduce end-to-end delay for CRAHNs. In this regard, we design the Media access control (MAC) and Physical (PHY) layer, and propose different spectrum aggregation algorithms for cognitive radio (CR) users. We propose two different...
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