Cooperative Interference Game in Cognitive Radio Hidden Terminal Scenario

Hidden terminal problem in spectrum sensing is one of the most challenging problems in cognitive radio network(CRN).To tackle this problem,we propose a novel Cooperative Interference Game scheme in this paper.The scheme adopted full duplex(FD)mode to sense over multiple sub-bands in an iterative manner without extra sensing devices.The implementation algorithm of the proposed scheme is consisted of three modules:the formulation of the maximum transmit power limitation of second user(SU);the self-interference cancellation coefficient;and the optimal location of SU for an optimized low collision probability.Monte Carlo simulation proved that compared with cooperative spectrum sensing,the proposed scheme significantly improves the performance of spectrum detection and mitigates hidden terminal problem to a large extent with less energy consumption.

Grouping Decision Algorithm for Dynamic Terminals in Random Access Networks

This paper proposes a grouping decision algorithm for random access networks with the carrier sense multiple access (CSMA) mechanism, which can balance the traffic load and solve the hidden terminal issue. Considering the arrival characteristics of terminals and quality of service (QoS) requirements, the traffic load is evaluated based on the effective bandwidth theory. Additionally, a probability matrix of hidden terminals is constructed to take into account the dynamic nature of hidden terminal relations. In the grouping process, an income function is established with a view to the benefits of decreasing the probability of hidden terminal collisions and load balancing. Then, we introduce the grey wolf optimization (GWO) algorithm to implement the grouping decision. Simulation results demonstrate that the grouping algorithm can effectively alleviate the performance degradation and facilitate the management of network resources.

Warehouse Environment Parameter Monitoring System and Sensor Error Correction Model Based on PSO-BP

The warehouse environment parameter monitoring system is designed to avoid the networking and high cost of traditional monitoring system.A sensor error correction model which combines particle swarm optimization(PSO)with back propagation(BP)neural network algorithm is established to reduce nonlinear characteristics and improve test accuracy of the system.Simulation and experiments indicate that the PSO-BP neural network algorithm has advantages of fast convergence rate and high diagnostic accuracy.The monitoring system can provide higher measurement precision,lower power consume,stable network data communication and fault diagnoses function.The system has been applied to monitoring environment parameter of warehouse,special vehicles and ships,etc.

Design and Evaluation of CRDMAC： Circular RTR Directional MAC Protocol for WANETs

Using directional antennas in Wireless Ad hoc Networks (WANETs) offers great potential of reducing the radio interference, and improving the communication throughput. Directional antennas, however, introduces new problems in the wireless Media Access Control (MAC), that is, the deafness and new hidden terminal problem, which may cause severe performance degradation. To solve the problems, we propose an effective Circular RTR Directional MAC (CRDMAC) protocol for WANETs by using a sub-transmission channel and Ready to Receive (RTR) packets, which modifies the IEEE 802.11 Distributed Coordinated Function (DCF). The sub-channel avoids collisions to other ongoing transmission, and the RTR packets notify the neighbor nodes that the mutual transmission has been finished. We evaluate the CRDMAC protocol through simulations and the results show that the proposed protocol outperforms existing DMAC (directional MAC) protocol and the CRCM (Circular RTS and CTS MAC) protocol in terms of throughput and packet drop rate.

Asymmetric Dual-Channel MAC Protocol for Multihop Mobile Ad Hoc Networks

In order to resolve the hidden and exposed terminal problems and improve the probability of concurrent packet transmissions for multihop Mobile Ad Hoc Networks （MANETs）, a novel slotted Asyrmaetric Dual-Channel Medium Access Control （ADC-MAC） protocol is proposed. It exploits sirmltaneous reservation with less collisions and conision-flee data packet transmissions, and achieves optimal transmission balance on the Control Channel （CCH） and Data Channel （DCH） by adjusting the relationship between Reservation Slot （RS） on the CCH and the data packet Transmission Slot （TS） on the DCH. Transmission interferences can be avoided by only observing CCH for the transmission time of a data packet. The proposed RS and contention micro-slot backoff mechanisms also greatly improve channel access efficiency. Simulation results show that compared to IFEE 802. 11 DCF and -Mc protocols, the proposed protocol can achieve a throughput gain of 88% in singlehop networks and 151% in nltihop networks at the same total data rate.