An MMSE maximal shortening equalizer for 10GBASE-T Ether networks

Recently, IEEE is interested in specifying the next generation 10GBASE-T Ethernet network. Due to the limitations of the channel characteristics of Category 6 (CAT-6) unshielded twisted pair (UTP) cables, capacity of the channel is only slightly above the proposed 10 Gbps data rate. This poses a great challenge to the design of equalizers. This paper addresses the problem of designing a minimum mean-square error (MMSE) maximal shortening equalizer with decision feedback cancellation. Unlike traditional approaches such as the decision feedback equalizers (DFEs), the shortening equalizer optimally focuses the channel impulse response to a small number of taps. If a subsequent maximum likelihood sequence estimation (MLSE) equalizer is used, the performance loss caused by symbol-by-symbol hard decision of traditional equalizers can be reduced. However, due to the complexity involved in the shortening equalizers is generally prohibitive; it is difficult to apply them to systems using modulation with large constellations. To overcome this difficulty, we propose an equalizer that combines DFE and the shortening equalizer. Thus, with acceptable complexity, the shortened signal-to-noise ratio (SSNR) can be significantly improved.