Analysis of Widely Linear Equalization over Frequency Selective Channels with Multiple Interferences

In this paper, the error performance of linear (MMSE-LE) and widely linear (MMSE-WLE) equalizers is analyzed in terms of mean square error (MSE) and bit error rate (BER). This analysis is done in a system using improper modulations of type Pulse Amplitude Modulations (PAM) having inter-symbol-interferences (ISI) and/or inter-user-interferences (IUI). For this scenario, we derive theoretical expressions of both MSE and BER for the two equalizers. Analytical expressions developed in this paper are verified by computer simulations. It is worth mentioning that these expressions are valid for any number of interferers and any channel delay spread.