Research On Power Management Technology In The MAC Layer Of 802.11ah

802.11 ah is an amendment of 802.11 wireless networking standard,which uses 900 MHz license-exempt band.It has lower power consumption and better through-wall capacity.IEEE 802.11 ah standard is proposed to satisfy Internet of Thing(IoT)requirements for low power consumption,broad coverage and multi-user.Reducing power consumption of terminals is the most important goal of 802.11 ah.One of the key features of IoT scenarios is the huge amount of users with small amount of data transmission.Therefore,suitable power management technology is particularly significant in this scenario.This paper proposed an optimal Restricted Access Window(RAW)mechanism and an improved Target Wake Time(TWT)mechanism based on the novel technique in the MAC layer of 802.11 ah.Threshold and optimal RAW group size decision was introduced into the optimal RAW mechanism,which further highlighted the advantage of RAW though large number of simulation in massive-terminal scenarios.An improved Target Wake Time(TWT)mechanism is proposed to schedule the awake time of stations in multi-user scenario.TWT mechanism permits the access point(AP)to define a specific or set of times for individual stations(STA)to wake up from doze state to access the medium.It can be used to reduce energy consumption as TWT STAs may enter doze state until their TWT arrives.Contention is also decreased since simultaneous transmission is avoided.Considering that not all STAs are TWTfunctioned,AP allocates a non-TWT period of time for non-TWT STAs according to their buffered traffic.Simulation results show that the improved power management techniques in 802.11 MAC layer can not only improve throughput but also reduce the terminal energy consumption.Network performance in transmission delay and fairness has also been improved.