Achievable Rates in the SIMO-Uplink/MISO-Downlink of an FDD System with Imperfect CSI

In practical systems, the available CSI for coherent transmission can not always be assumed to be perfect. For instance, in the MISO-downlink of a single-user FDD system with multiple antennas at the BS and a single antenna at the user, the available transmit CSI is actually estimated, quantized, outdated and affected by feedback errors. On the other hand, in the reverse link of this FDD system, i.e. the SIMO-uplink, the available receive CSI is only estimated. The two links of this FDD system represent a two-way system, in which we encounter a tradeoff between the MISO-downlink and SIMO-uplink rate due to the feedback of the transmit CSI in the uplink. Taking into account this tradeoff, we analyze the achievable rates in both links of the described FDD system considering imperfect CSI and limited feedback.