| The proliferation of mobile devices and the desire to surf the Internet as much as you want in a room,without being tethered to cables,has brought us short-range wireless communication networks that rely primarily on multiple wireless communication technologies such as Bluetooth,infrared,and wireless fidelity(Wi-Fi)technology,etc.However,with the emergence of some emerging applications with higher service requirements,Wi-Fi technology,as one of the commonly used network access methods,can no longer satisfy users.Therefore,the IEEE 802.11 working group proposed the latest generation of Wi-Fi protocol,namely 802.11 be,and a variety of key technologies have been initially implemented in be,among which the most revolutionary is the multi-link technology.This paper takes the multi-link technology as the research center,and conducts a specific investigation and discussion.In this paper,a detailed investigation and elaboration are carried out on the multi-link device(MLD)and multi-link operation(MLO)in the multi-link technology.Among them,the MLD is a dedicated device for the multi-link technology,which supports the multi-link capability through a unique protocol framework.MLO is a general term for all operations of multi-link technology to realize communication on MLD,including the setting process of scanning association authentication,channel access process and communication process.Multi-link technology is based on MLD,through MLO to achieve simultaneous communication between access point(AP)MLD and user non-AP(Non-AP)MLD on multiple links.It brings a significant gain to the system throughput.However,the selectivity of multiple links and the multiplied energy consumption bring two hidden problems,which will be considered in this paper.One is the load imbalance problem brought by the multi-link selectivity to the AP MLD side.AP MLD’s support for multiple links brings more randomness to the communication between users and APs,that is,users can randomly select any link of AP MLD for data transmission without obvious frequency band limitation.But the fact is that each link has its own upper limit of capacity,and the problem of how to avoid too much load concentrating on one link needs to be solved urgently.In response to this problem,this paper proposes a multi-link balanced access scheme.According to the multi-link settings,the user information,that is,the user’s working link and capability support,is obtained on the AP MLD side in advance,and then the user’s working chain is reasonably allocated through an algorithm.The paths are on different links of the AP MLD,and finally the link switching is performed through the protocol to implement the assignment of the user’s working link.Through subsequent mathematical analysis and MATLAB simulation,the effectiveness of the proposed scheme is verified,that is,compared with the non-balanced access scheme,the system performance after the scheme is significantly improved.The second is the power saving problem brought by the multi-link energy consumption for the Non-AP MLD.Most of the Non-AP MLDs used by users are power storage devices,and the more communication links they have,the more energy consumption they have.Therefore,users need to charge frequently to supply energy before they can continue to use them.followed by a drop.Aiming at this problem,this paper proposes a multi-link power saving scheme,which is based on the power-save multi-poll(PSMP)mechanism in 802.11 n,and modifies the PSMP frame as little as possible to apply for multi-link,and then implement PSMP sequence scheduling for MLD users through the modified PSMP frame.In addition,considering the frequency division capability of AP MLD,the multi-link PSMPs are grouped to save spectrum resources,and the multi-link PSMP sequence based on frequency division is obtained.Finally,through mathematical analysis and simulation,the power saving effect of the multi-link power saving scheme in this subject is proved. |
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