Research On The Key Technology Of Millimeter Wave Roubust Communication

To meet the increasing wireless communication demands and the rigorous Quality of Service(QoS)requirements in terms of low latency and high reliability,the directional millimeter-wave(mmWave)communication technology with ultra high data transmission rate has become a key component of the future mobile communication system.However,the path loss of mmWave signal is relatively high,and the diffraction ability is poor.The directional beam based wireless link is susceptible to the degradation of the communication link quality or outage caused by obstructions.Therefore,an effective link recovery scheme for different outage scenarios to improve the robustness has great significance for mmWave communications.This thesis investigates the mmWave directional communication mechanism,propagation characteristics,and link recovery schemes under different outage scenarios.Firstly,the directional communication mechanism in IEEE 802.11 ad is introduced and analyzed.Then,we analyze the reasons why the mmWave link is easily interrupted from the perspectives of atmospheric attenuation and penetration loss.Meanwhile,the factors influencing transmission rate for mmWave link are analyzed.Finally,we discuss the total transmission rate and the outage probability of multi-beam concurrent communication.In addition,we introduce the pseudo–outage scenario in which the mmWave link can be quickly self-recovered after short outage duration.We firstly analyze the link maintenance mechanism in IEEE 802.11 ad and its disadvantages in the pseudo-outage scenario.Based on this observation,we propose a link detection and recovery scheme relying on the link outage duration,which includes a new link maintenance mechanism and the corresponding frame structure design.Simulation results show that the proposed scheme not only has a smaller overhead,but also has a shorter link recovery delay and a higher transmission rate.Furthermore,we introduce and analyze the beam switching mechanism in IEEE 802.11 ad under the mobility occlusion scenario,followed by the proposed beam switching scheme under both single-beam and multi-beam scenarios.In the single-beam scenario,we consider the signal to noise ratio(SNR)of the candidate beam pairs and the spatial isolation between the candidate beam pair and the blocked beam pair to comprehensively select the optimal candidate beam pair.In the multi-beam scenario,the probability of simultaneous outage of all beams is low.Thus,we consider the interference between candidate beam pair and available beam pairs to select the optimal candidate beam pair.Finally,simulation results show that the proposed scheme can improve the system performance significantly.