Design And Optimization Of Underground Wireless Network Based On Interference Alignment

The downhole wireless network refers to heterogeneous networks such as wireless sensor networks and wireless access networks deployed in mine tunnels and rock walls.The downhole wireless channel performance is affected by various factors such as path loss,reflection/refraction,multi-path fading,and machine noise.So it is complicated and varied,and its transmission loss is huge.Multi-input multiple-output(MIMO)technology can improve the capacity of the underground heterogeneous network channel,but the communication interference between nodes seriously inhibits the utilization of node resources;interference alignment(Interference Alignment,IA)technology is an emerging interference cancellation method based on spatial multiplexing,The core idea of IA is to exploit the channel transmission characteristics to spatially align multiple unintended data streams(interference streams)at the receiving node.This paper studies the design and optimization of downhole wireless heterogeneous networks based on interference alignment techniques.This paper mainly completed the following research work:1.The interference alignment model and optimization strategy based on the data stream precoding vector construction are proposed to solve the internal communication interference of the downhole multi hop wireless sensor network.Firstly,a system model based on time slot scheduling is set up in the light of the actual downhole conditions,and the principle of node interference alignment is discussed in detail.Secondly,We have put forward the construction strategy of the pre coding vector of the data stream in the sending node and the decoding strategy in the receiving node.Then this paper established a optimization model to maximizing the throughput and further transformed as a mixed integer linear gauge.Finally,we use CPLEX tool to solve the optimal solution of the problem.Simulation analysis shows that the proposed interference alignment strategy improves the average network throughput by 45%compared with the traditional interference cancellation strategy.2.Aimed at the inter-network communication interference of wireless access nodes to wireless sensor networks,this paper proposes a distributed interference alignment strategy based on channel reciprocity.Firstly,this paper presents the system capacity and precoding matrix structure of a single-hop wireless sensor network without interference.Secondly,analysing the interference of mobile access nodes to wireless sensor networks.After that,this paper makes the interference alignment algorithm based on MIMO channel reciprocity(exchange transmission node and receiving node).Finally,the simulation results under different signal-to-noise ratios and different antenna numbers are given.The results show that the proposed interference alignment strategy improves the system capacity between heterogeneous networks by an average of 20%over traditional orthogonal sharing strategies.3.The anti-jamming ability of MIMO technology is verified by experiments.Firstly,this paper presents the main form of the downhole hundred megabytes WLAN,namely,the working mechanism of the WiFi network.What's more,it analyzes the interference characteristics of the WiFi network,such as inter-network interference,2.4G co-channel interference,and external interference,in the actual underground environment.In the end,using MIMO technology to analyze the WiFi network interference experiment.Experimental results show that multi-antenna technology can enhance the anti-jamming performance of the network and increase the network rate.