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Real-time video streaming over wireless links imposes strong demands on video codecs and quality of networks. Many measures are made to design proper routing protocols and channel assignments (CAs) for multi-channel multi-interface (MCMI) wireless networks, since it can provide higher performance than single channel. However, there still has not been a well-studied proposal to guarantee real-time...
This paper proposes two optimal power allocation (OPA) schemes for two-hop wireless relay networks operating in amplify-and-forward (AAF) manner. All the relay nodes in the network participate in relaying information from the source to the destination. We explore the OPA schemes among the cooperative relays to maximize the received SNR at the destination. When the instantaneous channel state information...
When analyzing and simulating communication systems, we often use average packet error rate p̅e to modelize the effect of the physical (PHY) layer. With this average value, we analyze and simulate systems and obtain the average performance metrics such as delay, number of retransmissions, throughput or jitter. This approach is done with classical network simulator. Because of the computational cost,...
Recently, a cooperative paradigm in cognitive radio networks, where licensed user can leverage its own bandwidth to unlicensed user in exchange for relaying its traffic, has been advocated to further improve all participates' performance. However, it entails that all participates interrupt their communication in each time slot. We propose BBC, a novel bargaining-based cooperation mechanism. It allows...
Transmit diversity generally requires more than one antenna at the transmitter. However, many wireless devices are limited by size or hardware complexity to one antenna. Recently, a new class of methods called cooperative communication has been proposed that enables single antenna mobiles in a multiuser environment to share their antennas and generate a virtual multiple-antenna transmitter that allows...
The problem of anonymous wireless networking is considered when an adversary is capable of controlling a subset of routes in the network. For a desired quality-of-service (QoS), as measured by network throughput, the problem of maximizing anonymity is studied from a game-theoretic perspective. Anonymity is quantified using conditional entropy of the routes given the adversary's observation. The problem...
Cognitive Radios (CRs) are able to operate in a large attribute space and operational parameters are chosen from this space, depending on the sensed environment, to achieve best performance. In this paper we demonstrate that such choice of parameters and the attribute space impact robustness of the network under electronic and information attacks. Such impact results in various tradeoffs to be considered...
In this paper, we consider a wireless network consisting of a BS (Base Station) and MSs (Mobile Stations) where the BS employs the one-bit feedback quantized proportional fair scheduler for downlink transmission. We then examine the effect of the threshold value in the scheduler on the throughput and that on the information theoretic capacity. Numerical results exhibit that the characteristics of...
This paper addresses a transmission scheduling for wireless multi-hop network employing physical layer wireless network coding (PL-WNC). With PL-WNC, two distant nodes first transmit packets to an intermediate relay simultaneously, which then amplifies and forwards the received signal. The destination nodes decode the desired signals by using the a priori information which are their own packets or...
The growing concern of global climate change calls for a revolutionary change on the way of utilizing the energy. In terms of the ICT industry, energy efficiency needs to be considered as an important metric to evaluate a communication system, besides the conventional metrics such as quality of service, bandwidth efficiency, etc. Research should be done to raise the energy efficiency of communication...
Wireless protocols, for IEEE802.11a, provide multiple none-overlapping channels. In this paper, we present an integrated metric routing protocol for multi-channel network, called IMR. The metric of this protocol composes the channel status and node status. Simulation results show that this protocol improves network average throughput and decrease end to end delay efficiently.
By theoretical analysis, we discuss the performance of random access protocol by network coding in wireless relay networks. We present a novel method to increase the opportunity of network coding in relay node. By using this method, the performance of random access protocol in wireless networks can be improved especially in low traffic load. We compare the performance of this method with network coding...
Wireless networks are characterized by having limited resources accessed by a large number of mobile stations with distinct capabilities. In such challenged environment the dynamic control of resources is of major importance to mitigate the limitations of wireless networks, such as the impact of low data rate stations and wireless channel oscillations. Such augmented usage of wireless resources can...
In this paper we use an analytical model to study how two radio networks : a primary network and a secondary network can coexist within the same area. We use a very simple protocol, Aloha, for both radio networks, and tools borrowed from stochastic geometry to model the performance of our two networks. We show that the primary network and the secondary network can adapt their transmission parameters...
Relay selection enhances the performance of the cooperative networks by selecting the links with higher capacity. Meanwhile link adaptation improves the spectral efficiency of wireless data-centric networks through adapting the modulation and coding schemes (MCS) to the current link condition. In this paper, relay selection is combined with link adaptation for distributed beamforming in a two-hop...
We study the problem of distributed scheduling in wireless networks, where each node makes individual scheduling decisions based on heterogeneously delayed network state information (NSI). This leads to inconsistency in the views of the network across nodes, which, coupled with interference, makes it challenging to schedule for high throughputs. We characterize the network throughput region for this...
Numerous Queue-Length-Based (QLB) schedulers, both deterministic and randomized, can achieve the maximum possible throughput region of wireless networks. While randomization is useful in allowing flexibilities in the design and implementation of the schedulers, it may lead to throughput loss if it is not within limits. In this work, we focus on the N × N input-queued switch topology to identify the...
Current medium access control mechanisms are based on collision avoidance and collided packets are discarded. The recent work on ZigZag decoding departs from this approach by recovering the original packets from multiple collisions. In this paper, we view each collision as a linear combination of the original packets at the senders. The transmitted, colliding packets may themselves be a coded version...
In this paper, we propose the Nash bargaining solution for the interference problem in cellular networks. The base-stations of neighboring cells negotiate with each other to determine the best number of channels that should be allocated to their edge users. While cells optimize the allocated resources on a local level, the bargaining process acts as a common framework that combines the optimization...
In wireless multihop ad hoc networks, the hidden terminal problem severely degrades the overall performance. On the other hand, most existing solutions cause larger blocking areas and hence a more severe exposed-terminal problem. In this paper, we present a new Enhanced Busy-tone Multiple Access (EBTMA) medium access control (MAC) protocol. The proposed protocol minimizes the negative impact of both...
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