Wireless Communication Aided by Intelligent Reflecting Surface: Active or Passive?

In this letter, we consider an intelligent reflecting surface (IRS)-aided wireless communication system, where active or xmlns:xlink="http://www.w3.org/1999/xlink">passive IRS is employed to assist the between access point and a user. First, downlink/uplink separately optimize placement for rate maximization with active passive IRS. We show that given same number of elements, should be deployed closer receiver IRS’s decreasing amplification power; while in contrast, near either transmitter receiver. Moreover, optimized placement, shown outperform its counterpart when elements sufficiently large and/or active-IRS power too small. Next, both IRSs maximize weighted sum-rate uplink downlink communications. case, more likely achieve superior performance. This because optimal needs balance performance downlink, deploying regardless downlink.