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Network Coding is a recent technique that has many advantages such as reducing the bandwidth consumption and increasing the throughput. IROCX [1] is a routing algorithm that applies Network Coding while considering the interference impact. However, it assumes a constant transmission power. We extend IROCX by allowing the nodes to transmit with several power levels. Our approach, TC-IROCX (Topology...
The performance of a wireless local area network depends on the channel assignments among neighboring access points (APs). The limited number of non-overlapping channels may lead to severe interference scenarios if no appropriated spectrum planning is employed. Additionally, in dense urban areas it is usual to find wireless networks scenarios with interfering APs belonging to different administrative...
An important design goal for wireless local area networks (WLANs) is the performance. It is well known that the major issue challenge to the performance in WLANs is the wireless interference. This leads to an ambience that depends on the channel assignments among interfering access points (AP). Due to the limited number of non-overlapping channels, severe interference scenarios may arise if an unappropriate...
We investigate the problem of minimizing the sum of the queue lengths of all the nodes in a wireless network with a tree topology. Nodes send their packets to the tree's root (sink). We consider a time-slotted system, and a K-hop interference model. We characterize the existence of causal sample-path optimal scheduling policies in these networks, i.e., we wish to find a policy such that at each time...
The opening of under-utilized spectrum creates the opportunity of substantial performance improvement through cognitive radio techniques. However, the real network performance may be limited since unlicensed users must vacate and switch to other available spectrum if the current spectrum is reclaimed by the licensed (primary) users. During the spectrum switching time, network partitions may occur...
We present a path selection algorithm that is used when deploying hard real-time traffic flows onto a chip-multiprocessor system. This chip-multiprocessor system uses a priority-based real-time network-on-chip interconnect between the multiple processors. The problem we address is the following: given a mapping of the tasks onto a chip-multiprocessor system, we need to determine the paths that the...
In wireless mesh networks, mesh nodes equipped with multiple radios tuned to multiple non-overlapping channels bring high network performance. As wireless mesh networks have been deployed in the urban area, dynamic channel allocation is more challengeable because co-located wireless networks are likely to be tuned to the same channels and may interfere with communication. This paper proposes an interference-aware...
In this paper, we propose a distributed topology control scheme in wireless mobile ad-hoc networks in which the transmit power of each node is adaptively adjusted based on both the number of its neighbor nodes and the amount of interference that the node generates to the neighbors.
In this paper, we examine the problem of channel assignment in multi-hop wireless networks in which each node is equipped with multiple transceivers. We summarize various approaches to transceiver channel assignment. Most approaches in the literature seek to assign a channel to each available transceiver. In contrast, we seek to achieve a baseline connected topology that conserves resources, keeping...
Cognitive radio ad hoc networks (CRAHNs) have become a popular network architecture for connecting mobile nodes thanks to the flexibility and adaptability of such type of network. In this paper, we propose a novel scheme for efficient routing design in CRAHNs. The proposed routing scheme firstly forms a simple directed graph for the given physical network. Using the simple directed graph, multiple...
In recent years, wireless mesh networks (WMNs) have attracted considerable interest from both academia and industry. WMNs offer attractive advantages such as easy installation, fast deployment, and low operating expense. For this reason, many cities and network operators have built WMNs to provide wireless Internet access in metropolitan areas. Despite their advantages, WMNs face numerous challenges...
In this paper, we address the problem of coordinated user scheduling for the downlink of a multi-cell distributed antenna system (DAS). With the practical assumption that only large-scale channel state information (CSI) is known at the transmitter, a low-complexity greedy scheduling scheme is proposed. In order to provide fairness among users, the proposed scheme adopts round-robin scheduling within...
The multi-user medium access mechanism OFDMA has to provide each node with a given amount of radio resources. In this paper we present a new distributed algorithm for the allocation of resource blocks in an OFDMA ad hoc network. We are principally interested in allocating resources fairly because the ad hoc networks which we work on are dedicated to be deployed in the areas of natural or man-made...
This paper discusses about the effects of simple air-to-air analog repeaters and tilt variations at base station (BS) antenna for HSDPA enabled WCDMA macro cellular network, for two different network topologies (i.e. nominal clover-leaf and novel triangular); based on the numerical calculations and Monte Carlo based static simulations performed using MatLab. The target of this paper is to determine...
One of the challenges in Multi-Radio Multi-Channel Wireless Mesh Networks is the assignment of channels to links such that connectivity is ensured and interference is minimized. Two links that are within interference range of each other could be assigned the same channel, which causes co-channel interference and decreases network throughput. In this paper, we identify the above problem in the Topology-controlled...
Ad hoc networks suffer from unfairness when multiple flows exist in the same interference region. The unfair channel distribution among competing flows is due to the random exponential back off algorithm used by the IEEE 802.11 Medium Access Control (MAC) protocol. The protocol can lead to unfair channel utilization among different flows, as some of the nodes may capture the channel for a long period...
We analyze the problem of buffer sizing for TCP flows in 802.11-based Wireless Mesh Networks. Our objective is to maintain high network utilization while providing low queueing delays. The problem is complicated by the time-varying capacity of the wireless channel as well as the random access mechanism of 802.11 MAC protocol. While arbitrarily large buffers can maintain high network utilization, this...
In Wireless Sensor Network MAC protocol designs, end to end latency is a field that many researches often focus on. RMAC, as a synchronizing MAC protocol, shows great advantage in reducing end to end latency than other MAC protocols. However, the performance of RMAC degenerates when encountered with interference hotspots. In this paper, we present an enhanced MAC protocol called SRMAC, which is derived...
Recent developments in wireless communication and embedded computing technologies have led to the advent of wireless sensor network technology. Hundreds of thousands of these micro sensors can be deployed in many areas including health, environment and battlefield in order to monitor the domain with desired level of accuracy. When wireless sensors are deployed in an area, the lifetime of the network...
In this paper, we present a joint optimization of power control, scheduling and relaying topology for multi-hop cellular networks aware of the intercell interference. To reduce the intercell interference in adjacent cells, cooperative diversity relaying scheme (COOR) is used in the system to reduce the transmission power needed to meet the same SINR threshold as the conventional relaying scheme (CONR)...
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