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Spatial reuse has been shown to be critical for efficient wireless networks. It is also well known that cooperative communication has the potential to significantly improve the network performance. How does cooperation affect the spatial reuse design in wireless networks? To answer this question, we investigate the impact of reuse on the throughput of multi-hop linear cooperative networks. The reuse...
There has been a growing interest in designing relay deployment strategies for cooperative wireless networks. In this paper, we focus on multi-hop, cluster-based, linear networks. Several relay selection strategies are applied to achieve the cooperative diversity benefits. We derive the number of hops that minimizes the end-to-end outage probability. On the other hand, if the required overhead for...
The use of commercial off-the-shelf (COTS) technologies in military environment is attractive, but in tactical communications, one of the biggest challenges is the jamming/interference tolerance of the deployed systems. Interference tolerance is important also in public authority and in some special civilian wireless network set-ups. We present an experimental measurement-based study on jamming tolerance...
Delay is a critical QoS performance metric for Multi-hop Wireless Network (MHWN). It is well known that schemes that give a higher data rate to the link with larger queue length can achieve high throughput performance. However, this queue-length-based approach may potentially suffer from large (even infinite) packet delays due to the subsequent contention problem caused by the next-hop arriving packets...
In order to ensure a reliable and efficient end-to-end communication among the network nodes in a Mobile Ad Hoc Network (MANET), an appropriate routing protocol is needed. In this paper, we present an extensive simulation-based comparison of three well-known MANET routing protocols (AODV, DSDV and OLSR) evaluating their performance in three real-life scenarios. Considering various performance metrics...
Performance verification and evolution is a very important step for some features to implement in the current mobile communication commercial networks. During the period of the field trial for these new features, user equipment is restricted to its development and price. Usually, Orthogonal Channel Noise Simulator (OCNS) is employed to simulate the environment of real network with multiple users....
Power line Communications (PLC) has gained a lot of interest for the last mile or access because the normal electric power line is utilized for transmission also communication signals. Considerable research effort has been extended on investigating the technologies about the physical (PHY) layer and the medium access control (MAC) layer. But the transmissions scheduling is still a key design problem,...
In multi-hop networks, conventional unipath routing approaches force the data transmission to follow a fixed sequence of nodes. In this paper, we widen this path to create a corridor of forwarding nodes. Within this corridor, data can be split and joined at different nodes as the data travels through the corridor towards the destination node. To split data, decode-and-forward OFDMA is used since with...
In this paper, we have investigated the use of transparent relay station to improve the throughput of the IEEE 802.16j Mobile Multi-hop Relay (MMR) WiMAX network. Simulations are performed using OPNET Modeler, and only VoIP application is considered. The result shows transparent relay station does improve the throughput of WiMAX network with some coverage extension.
Physical-layer network coding (PNC) employs interactive communication among neighbor nodes by using a proper modulation-and-demodulation technique to improve the communication ability. Most traditional routing protocols in wireless network are designed to reduce or avoid signal interference but do not have the merit of the physical-layer network coding. As a result, the throughout of network can hardly...
Multi-channel technology can reduce the interference and improve the performance. Based on the receiver directed transmission (RDT) multi-channel MAC protocols, we propose the RSM protocol by using split time mechanism to address the multi-channel broadcast problem in RDT protocol. As shown in the simulation experiment results, the RSM protocol can be applied to multi-hop wireless sensor networks.
Congestion control in multi-hop infrastructure wireless mesh networks is both an important and a unique problem. It is unique because it has two prominent causes of failed transmissions which are difficult to tease apart - lossy nature of wireless medium and high extent of congestion around gateways in the network. The concurrent presence of these two causes limits applicability of already available...
In this paper, a dynamic Sub-channel Assignment Algorithm (DSA) based on orthogonal frequency division multiple access (OFDMA) technology operating in time division duplexing (TDD) and a new routing protocol are proposed. The proposed dynamic Sub-channel Assignment Algorithm solves several drawbacks of existing radio resource allocation techniques in OFDM system used in ad-hoc and multi-hop networks,...
In this paper, we have proposed secondary user (SU) resource assignment scheme for a multi-hop cognitive radio network. In Multi-hop networks, since each link has different SNR because of their different distance between the stations and some other circumstance, it degrades the end-to-end throughput. To overcome this problem, we have proposed to give a channel priority in each link based on the link...
Wireless multi-hop network has a solidarity property in which each link consisting of the multi-hop interferes mutually and so the increase of one link's rate results in the decrease of the other links' rate. In the multi-hop link, the end-to-end throughput between source and destination is restricted by the lowest link rate, so the max-min fair allocation on the link rates is an optimal strategy...
Present years showed increasingly active competition on the mobile market. Considering rapid technology development and its business implications, operators need to steer the market trend and take faster response than competitors in order to survive and to keep growing. Rich spectrum of alternative 3G network upgrade directions opens a debate on the applicable and convenient evolution strategy providing...
This paper proposes a simple scheme to optimise the end-to-end user throughput of small, multi-hop wireless networks. The scheme which involves the introduction of small delays between successive packet transmissions at the source node has been tested on an indoor wireless mesh testbed for uni-directional flows of data traffic with nodes that use Chirp Spread Spectrum technology. Results from a series...
This paper addresses the design of an innovative scheduling algorithm which optimizes the performance of Multimedia Broadcast Multicast Service (MBMS) in High Speed Packet Access (HSPA) networks. The proposed policy is based on the subgrouping approach which splits multicast members into subgroups and applies a subgroup-based Adaptive Modulation and Coding mechanism. The optimal number of multicast...
The objective of this paper is to study the latest mobile technologies such as HSDPA (High Speed Downlink Packet Access) or 3.5G, and an approach to its successor LTE (Long Term Evolution) or 4G using network simulator called NS-2. First 2G technology came into existence which enabled mobile users with the technologies such as GSM, TDMA and CDMA. It also provided SMS services. After 2G many advanced...
The back-pressure based scheduling policy originally proposed by Tassiulas et al. in [1] has shown the potential of solving many fairness and network utilization related problems of wireless multi-hop networks. Recently, the scheduling policy has been adapted in random medium access protocols such as CSMA/CA using prioritization of MAC layer transmissions. Here, MAC priorities are used to provide...
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