Research On Channel Resource Allocation Of WLANs In Dense Scenarios

With the wide deployment of Wireless Local Area Networks(WLANs)and the rapid development of intelligent terminals,the demands for communication services is growing explosively with the higher requirements for WLANs.In order to improve the communication quality of WLANs,channel bonding in the 802.11 n means that the user combines two adjacent free basic channels to form a wider bandwidth channel for data transmission,and the channel bonding is further developed in 802.11ac/ax.Based on dynamic channel bonding,the most channel allocation schemes maximally occupy idle channels for oneself.However,it will cause the shortage of channel resources with the lack of system performance in dense scenarios.Therefore,the channel bonding scheme in dense scenarios need to be improved.Additionally,Orthogonal Frequency Division Multiple Access(OFDMA)introduced in 802.11 ax is for the multi-user downlink and uplink transmissions in a WLAN,and it derives the resources allocation more meticulous.In the downlink transmission,the Access Point(AP)is able to allocate Resource Units(RUs)reasonably based on cache information.However,in the uplink transmission without cache information,a combination scheme of Random Access(RA)and Scheduled Access(SA)is required.But there is no mature solution that allocate RUs for RA or SA reasonably according to the distribution of the different data packets.This thesis mainly studies the recourses allocation based on channel bonding and OFDMA in dense scenes.In our research,the channel recourses of one WLAN will be obtained by the AP,then the resources are decided whether for uplink or downlink.It is divided into two aspects according to different allocable resources:(1)Channel resources allocation based on channel bonding.According to the probabilistic game of Nash Equilibrium,an objective function based on throughput expectations is constructed for the system which consists of multiple WLANs,and the optimal probability space of channel bonding is solved by the interior point method.Moreover,an allocation scheme of channel resources is proposed with the selection of strategies based on the probability space,which means that the AP selects the channel bonding strategy based on probability space in different channel states.Compared with the dynamic channel bonding scheme,the simulation results show that the proposed scheme improves the overall system performance with the reducing use of channel bonding.(2)RUs allocation for multi-user uplink transmission based on OFDMA.For multiuser uplink transmission in a single WLAN,a RUs allocation scheme based on total access delay is proposed.Based on the existing combination scheme of RA and SA,an objective function which includes the total users access delay is designed based on the analysis of free competition model,and the optimal RUs allocation is solved by integer programming.In addition,users are divided into two categories with the setting of different weights according to the type of the generated data.The simulation results show that the proposed scheme can get the appropriate RUs allocation according to the distribution of different types of data,and it can guarantee the system throughput and reduce access delay.