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In this paper we consider an interference-free multi-beamforming protocol for multi-source multi-destination relay networks. The new protocol adopts the amplify and forward policy as its cooperative transmission strategy and adjusts the weights of relays to realize an improved multi-pair source-destination data transfer. We in particular investigate the issue how to choose the weights of relays to...
In this paper, we address the incentive-based relay-selection problem over multi-source and multi-relay wireless networks. A two-side market game approach is employed to jointly consider the benefits of all sources and relays. The equilibrium concept in such games is called core. The outcomes in the core of the game cannot be improved upon by any subset of players. These outcomes correspond exactly...
Medium access in ad-hoc wireless networks must be performed in a distributed fashion due to lack of coordination between nodes. Specifically, when nodes are capable of receiving more than one transmission simultaneously, the design of distributed medium-access mechanisms that efficiently exploit the receiver's capability becomes more challenging. Adaptive probabilistic medium access for ad-hoc wireless...
In a protocol assisted switched diversity (PASD) system, the time separated repetition blocks are accumulated in order to increase decoding reliability. In this paper, we consider transmit antenna selection (TAS) protocols in a PASD system. To minimize system complexity we assume the feedback information is limited to the SNR of the current pair of antennas. We propose three TAS protocols : the random...
Delay Tolerant Networks (DTNs) are able to provide communication services in challenged networks where the end-to-end path between the source and destination does not exist. In order to increase the probability of delivery, DTN routing mechanisms may require nodes in the network to store and carry messages in their local buffer and replicate many copies. When the limited buffer is consumed, choosing...
In this paper we study opportunistic communication in two relay channels, the shared relay channel (SRC) and the X-relay channel (XRC). The shared relay channel consists of multiple non-interfering source-destination pairs sharing one relay. The X relay channel is a multi-source multi-destination network where each source has a message for each destination and the network is assisted by one relay...
With demands increasing in lunar and Mars explorations, the need for a new space communication standard protocol is becoming more and more critical. The DTN Research Group (DTNRG) is developing a series of communication protocols with new architecture, generally called DTN protocols, to tolerate highly stressed communication environments with long propagation delays and frequent link disruptions....
Due to the dynamic topology and non infrastructure, network participants cooperate with their neighbors to route packets. The lack of centralized services allows mobile ad hoc networks to be easily and swiftly deployed, but make it difficult to check others' identities on the other hand. Cryptographic tools have been introduced to secure group communications, such as private and public key infrastructure...
TCP experiences severe performance degradation in cislunar communications because of some assumptions built into its design. Delay/disruption tolerant networking (DTN) is a class of network techniques that is developed to work over Internet protocols to accommodate long link delay and frequent link disruptions in space communication environment. Most of the work concerning DTN protocols and techniques...
In this paper, we propose a new channel access protocol for transmission over cooperative ad-hoc networks. The proposed protocol, which aims at minimizing the number of blocked nodes and consequently improving the system throughput, employs directional antennas at both source and relay stations. The network performance under the proposed settings is modelled using continues Markov chains. Steady state...
Mobile location estimation via the use of a spatially-dependent signal database is of growing importance. However, this location estimation method usually requires an a priori experimental measurement campaign. To overcome this drawback we propose here a new method of location estimation via the real-time creation of a virtual signal database. The virtual database is created on-demand by an optimized...
Optical burst switching (OBS) is one promising method for data transfer in photonic networks based on a WDM (Wavelength Division Multiplexing) technology. In the OBS scheme, the wavelength is exclusively reserved along the source and destination nodes, when the burst data is generated at the source. Then, efficient data transfer is expected. However, its performance is heavily dependent on the number...
In this paper, an Irregular Distributed Space-Time (Ir-DST) coding scheme is studied in the context of a twin-relay aided network in which the successive relaying protocol is employed. A tight upperbound of the successive relaying aided network's capacity is given. The distributed codes at the source and relays are jointly designed with the aid of Extrinsic Information Transfer (EXIT) charts for the...
Capacity and power consumption are two main bottlenecks in the wide deployment of Voice-over-IP (VoIP) over IEEE 802.11 wireless LAN, when mobile terminals are used, the impact on the Voice-over-IP (VoIP) by power consumption becomes more critical. In this paper, we analyze the capacity of VoIP traffic in 802.11 WLAN and do the relevant simulations with and without sleep strategy. We find that capacity...
In this paper, a new opportunistic feedback and user selection protocol is proposed for the multiple antenna downlink. The proposed scheme uses the structure of zero-forcing dirty paper coding (DPC) at the transmitter and selects users using a contention-based feedback channel. The user selection procedure is divided into stages and within each stage, a user is selected for one spatial channel (defined...
In this paper we propose a transmission range reduction scheme for a clustered wireless sensor network (WSN), in order to reduce power consumption while maintaining the network connectivity, particularly in scenarios where consecutive reporting of sensing values is inherent in the network. The platform WSN is based on a multi-hop clustering algorithm, where clusterheads send information to the sink...
Ethernet networks are evolving from the enterprise to the carrier thus facing new demands and requirements. Therefore, a set of new control approaches are being defined for Ethernet. Amongst these, IEEE 802.1aq Shortest Path Bridging (SPB) aims to assure the transmission of unicast and multicast frames on the shortest path in a bridged network. Three protocols have been proposed for the control of...
The outage behavior of decode-and-forward (DF) relaying protocol over an asynchronous cooperative network is examined when orthogonal frequency division multiplexing (OFDM) is used to combat synchronization error among the transmitting nodes. We consider non-orthogonal selection DF (NSDF) and orthogonal selection DF (OSDF) protocols, respectively, over a single relay and a two relay cooperative network...
In this paper we introduce a new MAC protocol called Continuous Contention-Assisted Transmission (CAT) for wireless Ad-hoc network. This proposed protocol is based on Carrier sense multiple access with collision avoidance (CSMA/CA) but we have modified the ACK packet and re-designed mobile stations behavior so that they could continuously transmit data without contention. Our proposed algorithm tries...
Telecommunications networks are composed of functional layers acting in cascade. Quality of service (QoS) derives from the action of each layer that must assure a specific level of quality to the upper layer in terms of performance parameters. The action is called vertical QoS mapping and is provided through algorithms that compute the bandwidth necessary so to assure the requested QoS when information...
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