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Mobile ad hoc networks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. This paper presents a cross-layer mechanism for efficient video transmission over this type of networks. The proposed mechanism consists of a priority-scheduling...
We investigate in this paper the resource allocation in wireless multi-hop network and we propose a cross layer based scheduling that takes into account the efficiency of advanced (smart) antenna techniques to increase network capacity by maximizing the number of concurrent transmissions without increasing interference. The proposed algorithm is applied to a WiMAX multi-hop network simulated using...
In this paper, we study the resource allocation problem in orthogonal frequency division multiple access (OFDMA) systems. An analytical approach based on an optimization problem formulation for the time-frequency spectrum allocation matter is proposed. The optimization problem takes into consideration heterogeneous constraints belonging to two different layers, leading to a cross-layer approach. The...
This paper deals with the problem of relay assignment in cooperative networks. We consider a network which consists of N nodes and a single destination. Each node is a potential relay to help other nodes to communicate with the destination. The problem is how to assign some nodes (as relays) to some nodes (as sources) in order to optimize a convenient objective function in the network. To find the...
This paper considers a wireless cooperative OFDMA network with a base station and some relays. The relays adopt the decode-and-forward protocol and can assist the transmission from base station to mobile stations. The objective is to maximize the system transmission rate of downlink under various constraints. The optimal solution for such radio resource allocation problem has high computational complexity...
Conventional single layer processing in Cognitive Radio Networks (CRN) can incur significant time costs in transferring information between the various layers of the Open System Interconnection (OSI) model, due its innate sequential structure. This is especially a problem for CRN which usually only has a narrow time window to access spectral gaps of either licensed or other secondary users (SU). To...
Hybrid ARQ (HARQ) schemes operate at the PHY and Medium Access (MAC) layers and their performance have been naturally studied at the MAC level. However, all the modern systems are going to be running under the IP protocol. Therefore, in order to get realistic performance of the whole system considering the multiple layer stacks, performance analysis at the IP layer is crucial. Very little work has...
Much attention has been paid to schedulers exploiting multiuser diversity in wireless networks, because such schedulers can increase the information theoretic capacity. It is, however, known that there exists a tradeoff between capacity and fairness achieved by schedulers exploiting multiuser diversity. Due to its good balance between capacity and fairness, the one-bit feedback fair scheduler is considered...
We investigate the throughput maximizing data transmission strategy of an energy harvesting node which is able to harvest and store energy for communication. Solar cell and rechargeable battery technologies have made such nodes feasible. In addition to the energy arrival process and the battery capacity limitation, the energy consumption of the circuits of the node also plays an important role in...
Medium access control MAC layer plays an important role for energy management in wireless sensor network (WSN). In this paper we present an adaptive wake-up-interval scheme for preamble sampling (MAC) protocols for variable traffic in WSN. The wake-up-interval is updated based on the traffic status register (whose contents depend on the presence of messages for a particular node). The proposed algorithm...
In this paper, we propose a distributed turbo-like coding scheme for wireless broadcast networks with relays. We first consider a scenario where a base station communicates with a mobile station with the help of a relay. The relay decodes the information from the base station and it re-encodes it to generate some extra redundancy, which is transmitted to the mobile station. Orthogonal frequency division...
Both cooperative transmission and autonomic networking have emerged recently as very promising technologies ready to become the key components of network of the future. Cooperative transmission capitalises on the exploitation of radio channel diversity provided by additional relay nodes forming virtual antenna arrays. Especially in dense set-ups, there appears an urgent need for the exploitation of...
Wireless systems based on WLAN (802.11), ZigBee (802.15.4) and Bluetooth (802.15.1) are continuously deployed in new applications covering consumer, industry or medical fields. Especially, Bluetooth is recommended by the Health-Care-Organization for medical applications as frequency hopping is considered as a robust scheme. However dealing with frequency-dynamic sources of interference in the 2.4GHz...
Cross layer scheduling techniques rely on accurate system state information, in particular the channel state. Since effective link gains are inherently time-varying, scheduling decisions have to be made every time the channel changes and hence accurate channel state information must be collected. In this paper we propose scheduling techniques that are robust to channel variations, allowing less frequent...
A well-known allocation technique, called bit-loading, results in the creation of tone maps which define, for each subcarrier on a particular transmission path, the appropriate constellation that has to be applied based on a link quality criterion. If this technique allows to efficiently optimize point-to-point transmissions in the network, it poses several challenges when transmitting the same information...
The paper investigates an approach to exchange quality of service information across the layers between third party applications and network functions for bearer resource management. The focus is on Parlay X Web Services which may be used to access functions for policy and charging control in all IP-based multimedia networks. A functional mapping of Parlay X interfaces onto network control protocol...
The OMEGA project has worked on defining a global standard for ultra broadband home area networks. The new standard consists of a unified home network, which hides the heterogeneity of wired and wireless connections from the end user. Applications can benefit from the capabilities of all the combined technologies constituting the home network. Moreover, the OMEGA home network reaches transmission...
Optimizing architecture of sensor networks is a current topic of research. This research field can be applied in several contexts such as environmental monitoring or body area network. Performance improvement in terms of bit error rate is a major challenge. Reducing processing time and simplifying the operations of the network are the two main key points to be improved. A number of architectures have...
This paper presents an original OFDMA-like technique intended to improve diversity propagation in the resource allocation procedure compliant with OFDMA and OFDM-TDMA schemes. The proposed technique combines sub-carrier interleaving process to sub-canalization in order to optimize interleaving spreading and introduce interleaving diversity in the OFDM(A) sub-channel allocation. The algorithm denoted...
Recent technical breakthroughs in communications have facilitated a cross-layered communication architecture for Intelligent Transportation Systems (ITS) aiming at ameliorating road safety and traffic efficiency. In this paper, we introduce an ITS station reference architecture recently developed by the ETSI TC ITS and ISO TC204 WG16. Then, we develop service interfaces for securing IPv6 ITS communication:...
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