2,748 research outputs found
Cross Layer Aware Adaptive MAC based on Knowledge Based Reasoning for Cognitive Radio Computer Networks
In this paper we are proposing a new concept in MAC layer protocol design for
Cognitive radio by combining information held by physical layer and MAC layer
with analytical engine based on knowledge based reasoning approach. In the
proposed system a cross layer information regarding signal to interference and
noise ratio (SINR) and received power are analyzed with help of knowledge based
reasoning system to determine minimum power to transmit and size of contention
window, to minimize backoff, collision, save power and drop packets. The
performance analysis of the proposed protocol indicates improvement in power
saving, lowering backoff and significant decrease in number of drop packets.
The simulation environment was implement using OMNET++ discrete simulation tool
with Mobilty framework and MiXiM simulation library.Comment: 8 page
Cognitive Adaptive Mac Based on Knowledge Based Reasoning For Cognitive Radio Computer Networks
In this paper we are proposing a new concept in MAC layer protocol design for Cognitive radio by combining information held by physical layer and MAC layer with analytical engine based on knowledge based reasoning approach. In the proposed system a cross layer information regarding signal to interference and noise ratio (SINR) and received power are analyzed with help of knowledge based reasoning system to determine minimum power to transmit and size of contention window, to minimize backoff, collision, save power and drop packets. The performance analysis of the proposed protocol indicates improvement in power saving ,lowering backoff and significant decrease in number of drop packets. The simulation environment was implement using OMNET++ discrete simulation tool with Mobilty framework and MiXiM simulation library
Energy Aware Multipath Routing Protocol for Cognitive Radio Ad Hoc Networks
Cognitive radio networks (CRNs) emerged as a paradigm to solve the problem of limited spectrum availability and the spectrum underutilization in wireless networks by opportunistically exploiting portions of the spectrum temporarily vacated by licensed primary users (PUs). Routing in CRNs is a challenging problem due to the PU activities and mobility. On the other hand, energy aware routing is very important in energy-constraint CRNs. In addition, it is crucial that CR users efficiently exchange data with each other before the appearance of PUs. To design a robust routing scheme for mobile CR ad hoc networks (CRANs), the constraints on residual energy of each CR user, reliability, and the protection of PUs must additionally be taken into account. Moreover, multipath routing has great potential for improving the end-to-end performance of ad hoc networks. Considering all these evidences, in this paper, we propose an energy aware on-demand multipath routing (EOMR) protocol for mobile CRANs to ensure the robustness and to improve the throughput. The proposed routing scheme involves energy efficient multipath route selection and spectrum allocation jointly. The simulation results show that our approach improves the overall performance of the network
CR-MAC: A multichannel MAC protocol for cognitive radio ad hoc networks
This paper proposes a cross-layer based cognitive radio multichannel medium
access control (MAC) protocol with TDMA, which integrate the spectrum sensing
at physical (PHY) layer and the packet scheduling at MAC layer, for the ad hoc
wireless networks. The IEEE 802.11 standard allows for the use of multiple
channels available at the PHY layer, but its MAC protocol is designed only for
a single channel. A single channel MAC protocol does not work well in a
multichannel environment, because of the multichannel hidden terminal problem.
Our proposed protocol enables secondary users (SUs) to utilize multiple
channels by switching channels dynamically, thus increasing network throughput.
In our proposed protocol, each SU is equipped with only one spectrum agile
transceiver, but solves the multichannel hidden terminal problem using temporal
synchronization. The proposed cognitive radio MAC (CR-MAC) protocol allows SUs
to identify and use the unused frequency spectrum in a way that constrains the
level of interference to the primary users (PUs). Our scheme improves network
throughput significantly, especially when the network is highly congested. The
simulation results show that our proposed CR-MAC protocol successfully exploits
multiple channels and significantly improves network performance by using the
licensed spectrum band opportunistically and protects PUs from interference,
even in hidden terminal situations.Comment: 14 Pages, International Journa
Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey
Wireless sensor networks (WSNs) consist of autonomous and resource-limited
devices. The devices cooperate to monitor one or more physical phenomena within
an area of interest. WSNs operate as stochastic systems because of randomness
in the monitored environments. For long service time and low maintenance cost,
WSNs require adaptive and robust methods to address data exchange, topology
formulation, resource and power optimization, sensing coverage and object
detection, and security challenges. In these problems, sensor nodes are to make
optimized decisions from a set of accessible strategies to achieve design
goals. This survey reviews numerous applications of the Markov decision process
(MDP) framework, a powerful decision-making tool to develop adaptive algorithms
and protocols for WSNs. Furthermore, various solution methods are discussed and
compared to serve as a guide for using MDPs in WSNs
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