Multi-user MIMO Uplink Precoding Method Based on SAR Constrained Energy Efficiency Maximization

Abstract

The invention discloses a multi-user MIMO uplink precoding method with energy efficiency maximization under SAR constraints. In this method, with the goal of maximizing system energy efficiency, the covariance matrix of the transmitted signal of each user in multi-user MIMO uplink transmission is designed by using the statistical channel state information, while satisfying the constraints of the maximum transmit power and the electromagnetic wave absorption ratio SAR. Among them, the algorithm design of energy efficiency maximization mainly uses deterministic equivalence principle, Dinkelbach transformation and iterative water filling algorithm to obtain the optimal covariance matrix of transmitted signals. When the channel state information changes, the UE dynamically implements an energy-efficient multi-user MIMO uplink transmission method that satisfies SAR constraints. The method of the invention can effectively improve the energy efficiency value of multi-user MIMO uplink transmission under the premise of satisfying the SAR constraint, and can significantly reduce the complexity of realizing wireless transmission.

Description

Technical field [0001] The present invention belongs to the field of communication, and more particularly to an energy efficiency maximizing multi-user MIMO uplink transmission method using the SAR constraints of statistical channel status information. Background technique [0002] Portable and wearable devices are widely used in wireless communications, but these devices generate electromagnetic (EM) signals at runtime, eM radiation, and pose potential health threats in the nearby users. Therefore, all wireless devices must comply with EM exposure restrictions. The ratio absorption (SAR) is a universally accepted user EM exposure measurement indicator. SAR is in units of W / KG, and the energy of the unit quality human tissue absorbs the energy. Typically, the maximum tolerance of SAR in partially exposed SAR is limited to 1.6W / kg or less. [0003] The traditional wireless communication transmission optimization problem is often based on the instantaneous channel status inform...

AI Technical Summary

Problems solved by technology

Generally, the maximum tolerated dose of SAR for partial body exposure is limited to less than 1.6W / kg

[0003] Traditional wireless communication transmission optimization problems are often based on instantaneous channel state information, but it is difficult to obtain instantaneous channel state information, and in fast time-varying channels, instantaneous channel state information is easily outdated

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