Research On Energy Efficiency Transmission Key Techniques For MM-WAVE WLAN

As the opening of domestic 45GHz spectrum,the standardization of the spectrum has been actively carried out.The related department has set up 802.11 aj task group, aiming at formulating next generation WLAN standard based on China millimeter wave spectrum.Recently, wireless local area network is blooming, which leads to the rapid growing of the number of its users, although the power consumption of WLAN is less than 3G network, WLAN has its own problem.The concept of green communication should be attached importance to.According to the energy efficient optimal problem, the paper researches on the improvement of MAC layer mechanism and the PHY precoding. The main work and innovations are as follows:1、The paper studied the implementation method of tradition dynamic bandwidth access mechanism in IEEE 802.11ac, compared the performance of dynamic bandwidth access mechanism to which of static bandwidth access mechanism.The simulation results showed that, the performance of dynamic bandwidth access mechanism is better in most circumstance. The paper also studied the trend of the performance of dynamic bandwidth access mechanism according to different length of PPDU, then reached the best length of PPDU conclusion based on energy efficiency. Then the paper discussed how the position of primary channel affect the performance of the access mechanism.At last, the paper studied the influence of the degree of the secondary channel interference, the simulation results showed that in the most slight region of interference, the performance of static bandwidth access mechanism is better, in the most serious region of interference, the performance of the two mechanisms is almost the same, in other region of interference,the performance of dynamic bandwidth access mechanism is better.2、The paper studied the location of IEEE 802.11aj channel and put forward an improved dynamic bandwidth access mechanism, weakened the concept of primary and secondary channel, the improved dynamic bandwidth access mechanism makes it possible to use the secondary channel when primary channel is busy, simulation results showed that the energy efficiency of the improved mechanism is higher than that of traditional mechanism.However, there is a drawback of the improved mechanism, sometimes STA can barely use the 1080MHz channel, so we proposed a redeeming mechanism which called Phase coexistence operation, the redeeming mechanism can make the interfering STA cease the 540MHz transmission.The compensation made it easier for 1080MHz STA to access to the channel. The simulation results showed that Phase coexistence operation can gain a higher energy efficiency in the extreme circumstance.3、The paper studied traditional precoding algorithm, proposed an optimal sum-rate precoding with transceiver impairments.First of all, the paper transformed the non-linear expression of rate to a linear expression based on mathematical derivation, then according to the sum-rate maximization optimal criterion, we come up with the algorithm of optimal sum-rate precoding with transceiver impairments. The simulation results showed that the energy efficiency of algorithm with transceiver impairments is higher than that without transceiver impairments.4、The paper proposed an optimal energy-efficient precoding with transceiver impairments.Besides the transformation of the non-linear expression of rate to a linear expression, we transformed the non-convex optimal criterion problem that is difficult to be directly solved into a subtraction solvable form according to the fractional programming theory, then we finally transformed the optimal criterion into a convex problem by introducing auxiliary variables.The optimal algorithm has a two level iteration. Simulation results show that the proposed algorithm is superior with taking hardware-impaired transceivers into account than without taking hardware-impaired transceivers into account.