Research Of Link Scheduling Mechanism In Dual-Hop 60GHz Wireless Networks

The dual-hop 60 GHz wireless network uses relay nodes for cooperative transmission,which can overcome the shortcomings of 60 GHz signals,such as short propagation distance and being easily blocked.And it has become an effective technical method to break through the performance bottleneck of 60 GHz network.Considering the factors such as time-varying demands and AP/Relay node overload,it has been an important technical challenge to realize the energy efficient link scheduling mechanism.Meanwhile,given that the 60 GHz link is easily blocked and its performance is significantly affected by the network environment,a low-latency link switching mechanism is urgently needed to cope with the dynamic network environment,thereby ensuring the reliability of network transmission.The existing research work has been focusing on improving network throughput and transmission delay,but it lacks consideration of time-varying users' demands and dynamic network environment.Aiming at the above problems,this thesis has studied the link scheduling mechanism for the dual-hop 60 GHz wireless network,which proposes solutions from the perspective of the global network and user nodes respectively to deal with the problem of time-varying users' demands and dynamic network environment.The specific contents include the following three aspects:Firstly,we have designed an efficient link scheduling mechanism for time-varying users' demands,which adopt a global and local link scheduling strategy to optimize the energy consumption of the entire network while ensuring the quality of users' service.First,we have presented a fine-grained network model and energy model and formulated the problem.On this basis,we have proposed a polynomial-time global scheduling algorithm that obtains a near-optimal link scheduling solution based on integer linear programming iterative relaxation and have analyzed the algorithms theoretically.Moreover,in order to deal with the dynamic network environment and meet the time-varying users' demands,we have presented ILPIR-LA algorithm based on the local adjustment strategy to realize the balance between network energy saving and link scheduling efficiency.Finally,we have conducted simulation experiments that validate our algorithms' effectiveness and efficiency.Secondly,we have designed a low-latency link switching mechanism for dynamic network environment,which aims to optimize its switching delay based on the802.11 ad protocol and to decrease the impact of dynamic network environment on the performance of 60 GHz link.First,we have analyzed the link-blocking model and proposed the link quality estimation method to filter a large number of candidate links rapidly by combining the beam model of the 60 GHz node.Then,we have designed the beam training method based on the binary search to reduce the delay of beam training.Combining with the link quality estimation method and the beam training method,we have designed the low-latency link switching mechanism to improve the stability of the user's link.Finally,we have implemented our proposed low-latency link switching mechanism and conducted the simulation experiments to evaluate its effectiveness and efficiency in the environment of ns-3 simulation system.Thirdly,combining the efficient link scheduling mechanism and the low-latency link switching mechanism,we have designed and implemented a dual-hop 60 GHz wireless network link scheduling prototype system.Finally,we have conducted the system verification and testing.In summary,this thesis has proposed a dual-hop 60 GHz wireless network link scheduling mechanism to meet the user time-varying demand and adapt to the dynamic network environment,which can provide important technical support for the highly efficient and reliable 60 GHz wireless network.