In OFDM relay networks with IQ imbalances and full-duplex relay station (RS),how to optimize pilot pattern and power allocation using the criterion ofminimizing the sum of mean square errors (Sum-MSE) for the frequency-domainleast-squares channel estimator has a heavy impact on self-interferencecancellation. Firstly, the design problem of pilot pattern is casted as aconvex optimization. From the KKT conditions, the optimal analytical expressionis derived given the fixed source power and RS power. Subsequently, an optimalpower allocation (OPA) strategy is proposed and presented to further alleviatethe effect of Sum-MSE under the total transmit power sum constraint of sourcenode and RS. Simulation results show that the proposed OPA performs better thanequal power allocation (EPA) in terms of Sum-MSE, and the Sum-MSE performancegain grows with deviating $\rho$ from the value of $\rho^o$ minimizing theSum-MSE, where $\rho$ is defined as the average ratio of the residual SIchannel at RS to the intended channel from source to RS. For example, the OPAachieves about 5dB SNR gain over EPA by shrinking or stretching $\rho$ with afactor $4$. More importantly, as $\rho$ decreases or increases more, theperformance gain becomes more significant.
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