Design of multiple MMSE subequalizers for faster-than-Nyquist-rate transmission |
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Authors: | Jae-Hyok Lee Yong-Hwan Lee |
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Affiliation: | Telecommun. Syst. Div., Samsung Electr. Co. Ltd., Gyeonggi-Do, South Korea; |
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Abstract: | We consider an equalization problem when the transmitted symbol rate is higher than the available channel bandwidth. This situation can happen in the uplink of the voiceband pulse-code modulation (PCM) modems whose transmit signal bandwidth is larger than the available channel bandwidth. Although the use of a minimum mean-squared error (MMSE) pre-equalizer is considered in the International Telecommunications Union (ITU)-T V.92 Recommendation, it may not provide an acceptable performance unless the channel condition is mild. As another approach to this problem, we consider the use of a bank of subequalizers, each of which compensates the part of the channel distortion, enabling the PCM-mode transmission over the channel where the V.92 scheme may fail. In this paper, a multiple subequalizer scheme is optimally designed in the MMSE sense, and its performance is compared with the MMSE pre-equalizer of V.92 in terms of the bit-rate-normalized signal-to-noise ratio. |
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