Optimization of Learning Time for Learning-Assisted Rendezvous Channel in Cognitive Radio System

Abstract

SUMMARYThis paper derives the optimal learning time for the learning-assisted rendezvous channel. One problem with the dynamic spectrum access system of cognitive radio is access channel mismatch between two wireless terminals. In the learning-assisted rendezvous channel, before exchanging packets for link connection, the rate of channel occupancy by the other system is estimated within the learning time; it is referred to as the channel occupancy rate (COR). High speed packet exchange is made possible by selecting a low COR channel. However, the optimal learning time and the impact of COR estimation errors have not been clarified yet. This paper analyzes the time to rendezvous channel (TTR), where TTR is the time needed to complete the rendezvous with a certain probability. The results indicate that the learning time and TTR have a concave relationship which means that the optimal learning time can be determined.

Design and Analysis of Multi-Channel MAC Protocol with Channel Grouping in Wireless Ad-Hoc Networks

“…When RTS-frame collisions and/or CW value increase, the transmission probability decreases. It is also seen that the frame transmission probability of [G, CW min , CW max ] = [3,15,255] is the highest in all the combinations in Fig. 11, which agree with the parameter set for the highest throughput as shown in Fig.…”

“…It can be confirmed from Fig. 8 that the highest saturation network throughput is obtained for [G, CW min , CW max ] = [3,15,255]. The simulation results show the same results as the analytical predictions.…”

Laboratory Experiment of Blind Adaptive Array with Subcarrier Transmission Power Assignment in Spectrum Superposing Scenarios

“…This approach also necessitates spectrum usage of the primary system. The secondary system should perform request-to-send (RTS) and clear-to-send (CTS) handshake, rendezvous protocols [6,7] or requires signaling knowledge of the primary transmitter [5]. These preprocessing might cause non-negligible overhead.…”