A Practical Packet Recovery Method Based on 802.11ac Network

Abstract

The invention discloses an actual data packet restoration method based on 802.11ac. The aims of the invention are that incorrect signal state information feedback and identification of a low signal to noise ratio can be realized, CSI estimation errors are corrected, the signal to noise ratio is improved, an AP and all parallel transmission users of the AP are allowed to select a higher transmission rate at last, and the throughput of the network can also be improved. The adopted technical scheme is as follows: 1) the AP monitors CSI estimation containing errors after receiving a wrong data packet, and divides carriers into ''good'' carriers and ''bad'' carriers with an error rate as the standard, and the AP sends a training sequence to a plurality of users by using downlink beam forming to pass through the ''bad'' carriers; 2) based on the received training sequence, the users estimate the CSI again and report information to the AP to pass through the ''good'' carriers; 3) the AP judges factors causing the CSI errors, and then use different restoration mechanisms; and 4) CSI restoration includes CSI restoration of three factors of carrier shift, undersampled estimation and the low signal to noise ratio, and a composite factor of the three factors.

Description

technical field [0001] The invention belongs to the field of wireless communication network security, and in particular relates to an actual data packet recovery method based on an 802.11ac network. Background technique [0002] The protocol standard of WIFI has been updated and developed for several generations, from IEEE 802.11a, 802.11b, 802.11g, to 802.11n and 802.11ac, the transmission rate is getting faster and faster, and the stability has been gradually improved. 802.11n is currently the most widely used WIFI protocol standard, and in the latest 802.11ac protocol, MU-MIMO is proposed, which is an emerging technology that allows multiple users to transmit data in parallel to the same multi-antenna AP at the same time , and will not interfere with each other. Therefore, MU-MIMO can effectively improve network throughput. [0003] MIMO technology can be simply understood as multiple cutting of network resources, and then synchronous transmission through multiple anten...

AI Technical Summary

Problems solved by technology

like Figure 1c , h * and x * is the correct CSI transmission data, user A’s h * misestimated as h 1 , h after orthogonal projection 1 proj x 1 will miscalculate x 1 , so x 2 can also be miscalculated, as Figure 1d , the AP first decodes the B signal, and the AP considers the projection signal h 2 proj x 2 Contains only the B signal, actually mixed with the A user's signal, such as h 1 *proj x 1 * , the interference of the A signal will reduce the signal-to-noise ratio of the B signal projection, so it is difficult for the AP to decode the B signal

Worse, once the AP fails to decode B, the subsequent decoding of A will also fail

[0009] In short, in the uplink MU-MIMO channel, no matter which signal is decoded by the AP first, as long as one CSI is decoded incorrectly, all parallel transmission data cannot be decoded correctly. In this case, MIMO transmission will become inefficient. , even doing retransmissions does not improve much

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