Double-correlated channels commonly occur due to insufficient scattering around both the transmitting and receiving antennas. In this article, the authors propose a linear precoding strategy with a modified system model over double-correlated channels. In this system model, an inner decorrelation strategy is added combined with precoding. First, a linear precoder that achieves minimum bit error rate (MBER) is proposed and analyzed based on the modified system model. The simulation results show that the bit error rate (BER) performance can be improved by decorrelation. Second, the influence of double correlation on multiple input and multiple output (MIMO) capacity is analyzed and simulated.