Research On Optimization Scheme Of OBSS Network Interference In WLAN Systems

With the popularity of intelligent terminals,the customers and requirement of wireless local area network are growing rapidly.Wireless local area network will be in highly dense deployment in the future.There are only three non-interfering channels in the 2.4GHz band,which are far behind the needs of users.Now,the new standard,IEEE 802.11 ac,operates in 5GHz band and extends the available bandwidth of users.However,the coexistence of IEEE 802.11 ac and legacy 802.11 a,802.11 n networks results in the overlapping of BSSs with different channel bandwidths.Hence,the highly dense deployment must lead to overlapping basic service set problem.It will result in strong co-channel interference and seriously affect user experience.Concerning this issue,this paper proposes two optimization schemes to solve the co-channel interference problem due to overlapping basic service set problem.The transmission power control technology is always used to solve the overlapping basic service set problem,but most of the current algorithms are centralized.Generally,these algorithms also require a central control device,which is complex to implement.For this problem,this paper proposes a DAC_TPC joint optimization scheme,which combines with channel selection,power control and access control technology etc.It permits each user to select a suitable AP.Then the selected AP adjusts the transmission power to change its coverage area based on the distance of the associated user.The above course can reduce collision domains and improve network performance.The simulation results show that the proposed scheme can improve the performance on network throughput,transmission fairness and packet loss rate etc.and finally verify the availability of the proposed scheme.In order to suppress the co-channel interference in overlapping basic service set network,Interference Alignment provides an efficient interference management mechanism and achieves the optimal degree of freedom.However,the existent interference alignment scheme is only applicable to two BSS overlapping scenes.For this problem,this paper proposes an interference alignment scheme for multiple overlapping BSSs scenarios,which assumes the users located in overlapping basic service set can associate with multiple APs.This scheme permits each node adopting interference alignment technology and aligns interference from different users through appropriate precoding design to completely eliminate co-channel interference and improve system capacity.The simulation results verify the validity of the proposed scheme.