QoS constrained power minimization in the MISO broadcast channel with imperfect CSI

Abstract

Abstract-We consider the design of linear precoders and receivers in a Multiple-Input Single-Output (MISO) Broadcast Channel (BC). We aim at minimizing the transmit power while fullfiling a set of per-user Quality-of-Service (QoS) constraints expressed in terms of per-user average rate requirements. The Channel State Information (CSI) is assumed to be perfectly known at the receivers but only partially at the transmitter. To solve the problem we transform the QoS constraints into Minimum Mean Square Error (MMSE) constraints. We then leverage the MSE duality between the BC and the Multiple Access Channel (MAC), as well as standard interference functions in the dual MAC, to perform power minimization by means of an Alternating Optimization (AO) algorithm. Problem feasibility is also studied to determine whether the QoS constraints can be fulfilled or not. Finally, we present an algorithm to balance the average rates and manage situations that may be unfeasible or lead to an unacceptably high transmit power.Index Terms-Broadcast Channels, imperfect CSI, MSE duality, QoS constraints, rate balancing, interference functions.

Channel Estimation and Hybrid Precoding for Frequency Selective Multiuser mmWave MIMO Systems

“…Taking these considerations into account, the measurement matrix at the m-th training step can be written as (36) in which the pilot s (m) [k] is a subcarrier-dependent scalar whose effect can be eliminated at the receiver by simply multiplying the received vector by (s…”

“…If we consider the transmission of M consecutive training frames, the received measurement vectors for each subcarrier can be written as an extension of (36) as…”