A New Strategy for Dynamic Channel Allocation in CR-WMN Based on RCA

Channel assignment has emerged as an essential study subject in Cognitive Radio-basedWireless Mesh Networks(CR-WMN).In an era of alarming increase in Multi-Radio Multi-Channel(MRMC)network expansion interference is decreased and network throughput is significantly increased when non-overlapping or partially overlapping channels are correctly integrated.Because of its ad hoc behavior,dynamic channel assignment outperforms static channel assignment.Interference reduces network throughput in the CR-WMN.As a result,there is an extensive research gap for an algorithm that dynamically distributes channels while accounting for all types of interference.This work presents a method for dynamic channel allocations using unsupervisedMachine Learning(ML)that considers both coordinated and uncoordinated interference.Unsupervised machine learning uses coordinated and non-coordinated interference for dynamic channel allocation.To determine the applicability of the proposed strategy in reducing channel interference while increasingWMNthroughput,a comparison analysis was performed.When the simulation results of our proposed algorithm are compared to those of the Routing Channel Assignment(RCA)algorithm,the throughput of our proposed algorithm has increased by 34%compared to both coordinated and non-coordinated interferences.

Modeling and Simulation of P-Aloha,CSMA /CA and MACAW Protocols for Underwater Acoustic Channel

Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks have been designed with negligible propagation delay. If it is deployed directly in an underwater environment,the UANs will perform inefficiently. In this paper,the characteristics of underwater acoustic channel are modeled and simulated by using the OPNET simulation tool,which are the speed of sound, propagation loss, and four sources for ambient noise: the turbulence,shipping,wind driven waves and thermal noise. The performance of pure Aloha( P-Aloha),carrier sense multiple access with collision avoidance( CSMA / CA) and multiple access collision avoidance for wireless local area network( MACAW) protocols in underwater acoustic channel environment are evaluated. The different performance of protocols in underwater environment is compared in the simulation.

AN IMPROVED CHANNEL DETECTION METHOD FOR IEEE 802.11N MIMO SYSTEM

Coexistence and interoperability between 20 MHz and 40 MHz device and modes of op-erations are stressed in standard IEEE 802.11n system.It is mandate to report the both sub-channels states to Medium Access Control(MAC) at receiver,since for 40 MHz device,it should serve not only 20 MHz but also 40 MHz signals receiving.Both energy detection and carrier sense are employed to detect channel state.In the case of 20/40 M mode,the power difference between the two sub-channels is also detected in order to report the channel state accurately.The simulation results demonstrate that the performance of the proposed methods are much better than the methods which just employ energy detection.Besides,the simulation results show that the proposed methods ensure that the channel sensing is not a roadblock of IEEE 802.11n system design.

Analysis of Multi-Channel and Slotted Random Multi-Access Protocol with Two-Dimensional Probability for Ad Hoc Network

A higher quality of service （QoS） is provided for ad hoc networks through a multi-channel and slotted random multi-access （MSRM） protocol with two-dimensional probability. For this protocol, the system time is slotted into a time slot with high channel utilization realized by the choice of two parameters p1 and p2, and the channel load equilibrium. The protocol analyzes the throughput of the MSRM protocol for a load equilibrium state and the throughput based on priority. Simulations agree with the theoretical analysis. The simulations also show that the slotted-time system is better than the continuous-time system.