mance is about 20-25 dB for OFDM systems. This can be explained by the phase noise causing two effects: common phase error and inter-carrier interference. The former may have acceptable levels as previously assumed, but the latter stimulates an enhancement in Widely linear filters augment the data vector with its conjugate, thus providing the complete second-order statistical information when computed using the minimum mean square error cost function. Widely linear fil- ters have been proposed for applications such as interference cancelation, demodulation, and equalization for direct sequence code-division-multiple-access systems, and array receivers. A widely linear filter forms the estimate of a desired sequence d(n) through the inner product ywL(n) = wHx(n) where the weight vector W1 W2N-1] has double dimension compared to the linear filter and X(n) = [x(n)x*(n)] T with the definition x(n) = [x(n) x(n-1) x(n-N+1)]T. New Radio Access Physical Layer Aspects (Part 1) 379 self-interference cancellation performance, which is achieved by consecutively estimating and suppressing the ICI. The goal of digital self-interference cancellation is to remove the residual self-interference after analog self-interference cancellation especially that originated from NLoS reflections. Various signal processing and calculations performed after ADC for the purpose of self- interference cancellation are classified as digital self-interference cancellation. Since they operate in the digital domain, the baseband equivalent models of self-interference should be determined before calculation. The models include linear and nonlinear self-interference models. Once the self-interference signal is modeled as a function of the transmitted signal, it can be estimated from the transmitted and received signals. The residual self-interference is then reconstructed as the output of the function, and subtracted from the received signal [40,41]. 3.5 Operating Frequency Bands The new radio has been developed to operate in two distinct frequency re