A Hybrid Precoding Design Method for Practical Wideband Massive MIMO Systems

Abstract

The present invention provides a hybrid precoding design method for an actual broadband large-scale MIMO system. The method comprises the following steps: at a radio frequency end, first assuming that analog precoding on all the carriers is the same, and calculating an optimal analog precoding matrix by using complete channel state information according to a criterion of maximizing system spectral efficiency; according to characteristics of a phase shifter in an actual system, determining an analog precoding matrix for each carrier in practice, designing a phase correction matrix in a digital domain, correcting phase shift occurring in the analog precoding on different carriers in practice to approach an optimal analog precoding, and multiplying the phase correction matrix by the analog precoding matrix having a phase shift on each carrier to obtain the designed analog precoding matrix; and finally, designing a digital precoding matrix at a baseband by using equivalent low-dimensional channel state information, and multiplying the digital precoding matrix by the obtained analog precoding to obtain a hybrid precoding design scheme.

Description

Technical field: [0001] The invention belongs to the technical field of wireless communication, and in particular relates to a hybrid precoding design method for an actual wideband massive MIMO system. Background technique: [0002] Hybrid precoding is a research hotspot in massive MIMO. When the number of antennas is large (hundreds or thousands), it is impossible to equip each antenna with a specific radio frequency link (RF) due to power consumption and cost issues. Then It is very meaningful to study the deployment of massive MIMO with a small amount of RF. Hybrid precoding uses a low-cost phase shifter at the radio frequency to control the phase of the signal on the transmitting antenna to achieve analog precoding, which not only reduces the hardware cost, but also reduces the number of radio frequencies required by the system; at the baseband, the equivalent low-dimensional Channel state information (CSI) controls the amplitude and phase of the signal to realize digit...

AI Technical Summary

Problems solved by technology

On the other hand, in such a high-frequency band, in order to ensure the performance of the system, the processing accuracy of the hardware is very fine, which leads to the high price of millimeter-wave devices, so an intermediate frequency link is required

The common intermediate frequency is 2.75 GHz, which will lead to a bandwidth-to-carrier frequency ratio close to 0.5 to 1.5, so the impact of phase offset on analog precoding becomes non-negligible

Images