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Abstract. The paper proposes a XOR-based network coded cooperation protocol for the uplink transmission of relay assisted cellular networks and an algorithm for selection and assignment of the relay nodes. The performances of the... more
The total energy consumed by the radios is compared for a cooperative transmission (CT) protocol and a non-CT routing protocol, in a two-hop, single cluster, ad hoc network. The radio energy model is a function of parameter sets that are... more
In this paper, we propose a novel spectrally efficient cooperative transmission protocol for multiple access scenarios. Different to some existing cooperative multiple access schemes, the proposed scheme can exploit the availability of... more
In this paper, the impact of limited resources on achievable rates in relay channels is investigated. Resource limitation is modeled as a rate constraint, R, which constrains the rate at which a relay can reliably decode or source-code... more
In this work, joint routing and power allocation problem is formulated in an optimization framework for end-to-end outage minimization under the constraint of total permissible transmission power. A closed form solution for optimal... more
Future smart ocean applications require long distance and reliable communications to connect underwater sensors/robots with remote surface base stations. It is challenging to achieve such goal due to the harsh and dynamic underwater... more
The modern research has found a variety of applications and systems with vastly varying requirements and characteristics in Wireless Sensor Networks (WSNs). The research has led to materialization of many application specific routing... more
The modern research has found a variety of applications and systems with vastly varying requirements and characteristics in Wireless Sensor Networks (WSNs). The research has led to materialization of many application specific routing... more
In this work, we investigate a slotted-time relay assisted cooperative random access wireless network with multipacket (MPR) reception capabilities. MPR refers to the capability of a wireless node to successfully receive packets from more... more
A main distinguishing feature of a wireless network compared with a wired network is its broadcast nature, in which the signal transmitted by a node may reach several other nodes, and a node may receive signals from several other nodes... more
In this letter, we obtain the stable throughput region for a cognitive relaying scheme with a finite relaying buffer and imperfect sensing. The analysis investigates the effect of the secondary user's finite relaying capabilities under... more
Cooperative communication techniques have been proposed in order to improve the quality of the received signals at the receivers by using the diversity added by duplication of signals sent by relays situating between each transmission... more
Due to the broadcast nature of wireless signals, a wireless transmission intended for a particular destination station can be overheard by other neighboring stations. A focus of recent research activities in cooperative communications is... more
Wireless sensor networks where neighbor nodes can cooperate both at transmission and reception by using the cooperative multi-input multi-output (MIMO) technique are considered. Space-time diversity gain can be exploited to reduce the... more
In the context of cooperative Multi-Input Multi-Output (MIMO) techniques for wireless sensor networks, the transmission synchronization error impact is investigated in this paper and a new space-time combination technique is proposed.... more
In this paper, we compare cooperative networks using either coded amplify-and-forward, coded cooperation or distributed turbo coding, over quasi-static fading channels under the condition of identical data rate and power consumption. We... more
A goal of this paper is to combine the advantageous properties of multiple access codes (MAC) and space-time transmission (STT) in wireless relay communication systems. The use of MAC provides transmission with the separability of the... more
Wireless sensor network is collection of nodes organized in cooperative network. Due to unbalanced task allocation in WSN results in overloading and under loading of nodes. By keeping in mind parameters such as topology, number of nodes,... more
Wireless sensor network is collection of nodes organized in cooperative network. Due to unbalanced task allocation in WSN results in overloading and under loading of nodes. By keeping in mind parameters such as topology , number of nodes,... more
We consider the time synchronization of concurrent transmissions from a cluster of cooperating software defined radios (SDRs). In this type of cooperative transmission (CT), each cooperating node derives its timing autonomously from a... more
The opportunistic large array (OLA) is a particularly simple form of cooperative transmission. Recently, the OLA concentric routing algorithm with limited flooding and transmission threshold (OLACRA-FT) was proposed for energy efficient... more
This deliverable is written with two objectives in mind, and is organised as such. In the first part, it identifies the scope of the work package, introduces the key concepts and lays the foundation on which the work package develops.... more
We propose a cooperative transmission scheme for two users with one common relay using superposition modulation. It uses distributed Turbo codes (DTCs) for each user. The relay always decodes, then interleaves and re-encodes the decoded... more
We propose a cooperative transmission scheme for two users with one common relay using superposition modulation. It uses distributed Turbo codes (DTCs) for each user. The relay always decodes, then interleaves and re-encodes the decoded... more
Cooperative transmission techniques for ad hoc and wireless sensor networks are known to increase the network lifetime. Indeed, the improved spatial diversity allows a more efficient energy usage. Under Rayleigh fading assumption, the... more
Doutoramento em TelecomunicaçõesEsta tese apresenta um estudo sobre alguns dos protocolos de cooperação MAC para redes sem fios utilizando o sistema IEEE 802.11 multi-débito. É proposto um novo modelo de arquitetura para a categorização e... more
The multiple access channel (MAC) with many-user is a general model for massive machine type communications. In this paradigm, the number of users may be comparable or even larger than the coding blocklength $n$. In contrast, classical... more
In this paper, the performance of cellular networks with joint multicell processing and dedicated relay terminals is investigated. It is assumed that each relay terminal is capable of full-duplex operation and receives the transmission of... more
Although recent studies have shown the potential benefits of base station (BS) cooperation technology, existing schemes rely on the assumptions of (i) perfect backbone links between the central network controller (CNC) and the base... more
Cooperative transmissions have received recent attention and research papers have demonstrated their benefits for wireless networks. Such benefits include improving the reliability of links through diversity and/or increasing the reach of... more
Small chemical sensors are subjected to adsorption-desorption fluctuations which usually considered as noise contaminating useful signal. Based on temporal properties of this noise, it is shown that it can be made useful if proper... more
In this work, joint routing and power allocation problem is formulated in an optimization framework for end-to-end outage minimization under the constraint of total permissible transmission power. A closed form solution for optimal... more
We present the analysis of a multi-channel MAC protocol for wireless networks. We consider wireless networks in PMP (Point to Multi-point) configurations, with a base station (access point) and a number of clients associated with it. We... more
One of the most powerful ways to achieve transmission reliability over wireless links is to employ efficient coding techniques. This paper investigates the performance of a transmission over a relay channel where information is protected... more
We describe the key ideas behind our implementation of distributed beamforming on a GNU-radio based softwaredefined radio platform. Distributed beamforming is a cooperative transmission scheme whereby a number of nodes in a wireless... more
We describe the key ideas behind our implementation of distributed beamforming on a GNU-radio based softwaredefined radio platform. Distributed beamforming is a cooperative transmission scheme whereby a number of nodes in a wireless... more
Wireless multi-hop networks have become an important part of many modern communication systems. Opportunistic routing aims to overcome the deficiencies of conventional routing on wireless multi-hop networks, by specifically utilizing... more
Redundancy ensures reliable data for decision making. Reliable data plays a very important role in the analysis, monitoring and forecasting of system behaviour whereas bad quality data may provide erroneous result in decision scheme. In... more
A linear mesh network is considered in which a single user per cell communicates to a local base station via a dedicated relay (two-hop communication). Exploiting the possibly relevant inter-cell channel gains, rate splitting with... more
The capacity region of a Multiple Access Channel can be increased by feedback to the sources, since feedback enables cooperative transmission. Focusing on a linear cellular system (as for a highway or a corridor), a novel transmission... more
This work considers a dual-hop Internet of Thing (IoT) communications network where sensor nodes transmit data to a gateway either directly or via other nodes using dualhop communications. Each node employs separate transmission buffers... more
Multi-cellular radio systems are often limited due to the presence of cochannel interference. Physical layer concepts as e.g. interference rejection combining, optimize the receiver side and thus strengthen the signal while combating the... more
Multicellular radio systems are often limited due to the presence of cochannel interference. Proposed physical layer concepts, e.g. coordinated joint transmission and interference rejection combining, try to strengthen the signal while... more
Resumo-Neste artigo, consideramos um sistema de comunicação cooperativo MIMO (do inglês, Multiple-Input Multiple-Output) com um relay, em que codificação espaço-tempó e utilizada na fonte e no relay, para o provimento de ganhos de... more
Two algorithms based on an energy conserving dynamic transmit power threshold are proposed for improving the lifetime in relay networks utilizing selective relay strategies with Amplify-and-Forward (AF) relays. the lifetime of the relay... more
In this paper, the performance of a multi-hop network is investigated in which M sources have independent information to be transmitted to a far off common destination. Linear network coding technique is used by the intermediate relays to... more
We consider the problem of decodability when random linear coding (RLC) is performed on a stream of packets in a line network. First, we clearly define the problem of decodability for a stream of arriving packets, and discuss its... more
Background and Objectives: Routing and data aggregation are two important techniques for reducing communication cost of wireless sensor networks (WSNs). To minimize communication cost, routing methods can be merged with data aggregation... more