Precoding Design for Downlink Multiuser MIMO Systems with Deterministic Transmission Delay Constraints

In this letter, the weighted sum-rate maximization problem under the total transmit power constraint and deterministic transmission delay constraints for a downlink multi-user multiple-input multiple-output system is revisited. Initially, the non-convex problem is converted into a tractable form, which combines the log function with the product structure of Rayleigh quotients. Subsequently, the first-order optimality condition that the optimal precoding vector needs to satisfy is identified. Additionally, a low-complexity and efficient algorithm based on the generalized power iteration precoding algorithm to find the optimal precoding vector satisfying the first-order optimality condition is designed. The proposed scheme is a joint design of precoding matrix and power allocation regardless of the number of users and antennas. Numerical results demonstrate the advantage of the proposed precoding design with stringent constraint on deterministic transmission delay.