Backhaul Scheduling And RU Allocation In IEEE 802.11ax Dense WLAN System

With the increasing number of mobile devices and the gradual popularization of smart homes,users have higher and higher requirements on wi-fi coverage,rate delay,etc.,and wi-fi high-density coverage will become more and more common.At the moment,out of the lack of effective cooperation mechanism between Access Points(APs),interference will increase as the coverage density becomes increasingly serious,making user run into a plight where wi-fi signal strength is very strong but connection rate is so low,which results in the wireless resources waste.Therefore,effective collaboration between the APs will be the inevitable developing trend of dense WLAN.Most of the existing researches focus on AP collaboration based on channel allocation.Considering the limited number of orthogonal channels,this method is no longer applicable in dense WLAN.In 802.11 ax,a more delicate Resource Unit(RU)is proposed,which can meet the needs of simultaneous transmission of more links.However,synchronization is required before transmission.Currently,cooperation research based on RU allocation is only limited to second-level AP,which cannot be extendted due to the strict synchronization.Besides,the existing RU assignment research aims at improving network throughput but ignores the fairness between links.Aiming at the pain point of the lack of reasonable cooperation mode in the multi-level AP based on RU assignment,this paper proposes a new AP cooperation mode in the threelevel AP cascade scenario.With the main AP as the control center,the three-level AP cascade forms an independent "autonomous domain",and multiple autonomous domains coexist independently.The cooperation mode of "centralized scheduling within the domain and distributed negotiation among the domains" makes the APs cooperate with each other.In addition,the centralized RU assignment algorithm(Ruas)in the autonomous domain was proposed on the basis of the "centralized scheduling in the domain" cooperative mode.Aiming at maximizing network utility and fairness,the main AP collected the traffic of links in the autonomous domain and allocated RU.The simulation results show that Ruas algorithm can effectively improve the network utility in autonomous domain and guarantee the fairness between links in autonomous domain.For multiple autonomous domain RU assignment problem,we model it into multiple autonomous domains involved in game and prove this game to be potential game in interdomain cooperation way.Then Best Response-Randomly Escape(BR – RE)algorithm is proposed.The simulation results show that the BR-RE algorithm can converge and guarantee the fairness between autonomous domains without interfering with each other.