OFDMA Based MAC Protocols For The Next Generation WLAN

The MAC layer and physical layer of the next-generation WLAN adopt the IEEE 802.11 ax standard.This standard is scheduled to be released this year,and introduces the uplink orthogonal frequency division multiple access(OFDMA)for the first time,which enables multi-user parallel transmission in the WLAN.The design of new MAC protocols based on the new technologies involved in the IEEE 802.11 ax standard,including access coordination schemes and resource unit(RU)assignment schemes,is significant for improving the utilization of spectrum resources and network throughput in the next-generation WLAN.Aiming at coping with the problem of low RU utilization and unreasonable RU assignment which results in low network throughput in access coordination scheme of the next-generation WLAN,this paper designs a fair hybrid access coordination scheme based on OFDMA technology and propose a high throughput RU assignment scheme.And this paper built a corresponding simulation environment for simulation and analysis.The main work and innovations of this paper are included as follows:1.For coordinated access problem in the next generation WLAN,a buffer status report(BSR)fair transmission hybrid access coordination scheme based on OFDMA technology is proposed.Through the modeling and analysis of the access coordination scheme,the BSR transmission opportunity fairness factor is derived,and the fairness factor optimization problem is proposed.Through the optimization problem solving,the RU allocation scheme of maximizing the fairness factor is obtained.Through the simulation experiment,the performance evaluation and analysis of the hybrid access coordination scheme proposed in this paper is carried out,and compared with the existing polling scheme.The simulation results show that the proposed scheme can obtain a fairer BSR transmission opportunity in the uplink transmission based on OFDMA technology compared with the existing polling scheme.2.For the RU assignment problem in the next generation WLAN,a high throughput RU assignment scheme based on OFDMA is proposed.Firstly,based on the positions of RUs and channel conditions,the network throughput model is established,the network throughput rate is derived,and the optimization problem of maximizing network throughput is proposed.Secondly,by solving the optimization problem,the corresponding high throughput RU allocation scheme is obtained,and the flow and steps of the scheme are given.Finally,through simulation experiments,the performance evaluation and analysis of the scheme are carried out.We compare our scheme with the existing RU allocation scheme based on OFDMA and the traditional scheme of 802.11 ac without considering OFDMA.The simulation results show that our scheme can obtain the optimal WLAN throughput rate under the condition of positions of RUs and channel condition limitation,and our scheme is superior to the existing RU allocation scheme based on OFDMA and 802.11 ac conventional solution that without considering OFDMA in terms of throughput.