Lattice interference mitigation with mixed channel state information

We study the effect of mixed partial channel state information (CSI) on the performance of lattice interference mitigation schemes. The considered lattice scheme was shown to be equivalent to dirty paper coding when both transmitter and receiver share the same (perfect or imperfect) CSI. We derive a novel lower bound for the case that the transmitter and the receiver have different versions of imperfect CSI. The novel bound reveals that lattice interference mitigation is robust for various CSI error models. The bound is demonstrated for two scenarios of practical interest: frequency division duplex (FDD) and time division duplex (TDD). Both cases result in simple lower bounds, and also give insights on the system optimization. The novel bound is also demonstrated using simulation results for the FDD case.