Solving The Blockage Problem In60GHZ Wpans With Two-Way Relay Scheme

In recent years, we are witnessing an explosive growth in the demand for wireless networks. The huge amount of the bandwidth available in the unlicensed60GHz band, which is also known as the millimeter-wave band, has aroused a great deal of interest to develop new wireless communication techniques. The large bandwidth around60GHz (more than7GHz wide) may potentially enable the multi-gigabit wireless communication products and applications worldwide.In this paper, we investigated a promising physical layer network coding-based two-way relay technique for the emerging60GHz millimeter-wave wireless personal area networks (WPANs), in order to address the problem of throughput reduction in relay nodes caused by the blockage of links. Because of the small wavelength at60GHz frequency band, links may be seriously blocked by the involved obstacles such as furniture and humans. The key idea of the most common solution to handle blockage proposed by now is to substitute the two line-of-sight (LOS) links for the blocked link. However, this method reduces the throughput of the network by a factor of two, which may hence fail to provide the required QoS guarantees to realistic WPAN applications. Our suggested new approach introduces a two-way relay scheme using physical layer network coding to the60GHz millimeter-wave WPANs, which can accomplish information exchange within two time slots instead of four. Simulation results, such as bit error rate and throughput, demonstrate the effectiveness of the proposed two-way relay scheme in60GHz WPANs.But applying two-way relay sheme without considering the channel state is unacceptable, because it can affect the throughput. So, we further proposed Optimal Power Allocation (OPA) scheme to allocate limited power among the three nodes, in order to achieve the highest thoughput of the network. The simulation result shows that the OPA scheme can further improve the quality of network. So the application of the two technologies can solve the blockage problem successfully.In this paper, we first introduce the background and research status of60GHz millimeter wave WAPNs. Then we did the research of the channel model of60GHz mmilimeter wave WPANs and gave out the simulation result. Next we introduce the technology of two-way relay schemes and discuss the technology of physical layer network coding based two-way relay scheme in detail.In the fifth chapter, we applied the physical layer network coding based two-way relay scheme in60GHz millimeter WPANs, then we did some simulation and discussion.In the sixth part, we first did some research about impact of channel state to the network. Then we discuss the OPA scheme and gave the mathmetical result of OPA. At last we did some simulation and discussion.Finally we give the conclusion and discuss the further work of this paper.