# US 8,498,343 B2 · System for MIMO equalization of multi-channel transceivers with precoding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,498,343 B2 - Document ID: US8498343B2 - Status: Granted - Kind: B2 - Application number: 12/806,538 - Filed: 2010-08-16 - Published: 2011-10-20 - Granted: 2013-07-30 - Earliest claimed: 2009-08-24 - Assignees: Leanics Corporation - Applicants: Jie Chen; Keshab K. Parhi - Inventors: Jie Chen; Keshab K. Parhi - Web page: https://patentgrep.com/patent/US8498343B2 ## CPC - H04L 25/03343: {Arrangements at the transmitter end} - H04B 3/32: Reducing cross-talk, e.g. by compensating - H04L 25/03038: {with a non-recursive structure (H04L25/03031 takes precedence)} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract The present invention relates to data processing techniques in multi-channel data transmission systems. In this invention, a method to efficiently deal with FEXT is proposed and a circuit architecture to implement the proposed MIMO-THP equalizer is developed for the application of high/ultra-high speed Ethernet systems. The proposed method relies on the fact that FEXT inherently contains information about the symbols transmitted from the far end transmitters and it can be viewed as a signal rather than noise. Compared with the traditional FEXT cancellation approaches, the proposed design inherits both advantages of MIMO equalization technique and TH precoding technique, thus having better performance. Unlike the existing MIMO-THP technology, the proposed design completely removes the feedback loops in the existing MIMO-THP architecture. Therefore, pipelining techniques can be easily applied to obtain a high-speed design of a multi-channel DSP transceiver. ## Claims ### Claim 1 A far-end cross-talk (FEXT) canceller for a precoded multiple-input multiple-output communications system comprising a plurality of receivers, each receiver comprising: a first feed-forward equalizer (FFE) to process a first received signal, a second feed-forward equalizer (FFE) to process a second received signal, and a first summer to sum the outputs of the first and second FFE; a first decision device, comprising a first modulo device and a first slicer, to process the output of the first summer to generate a first tentative decision; a first feed-forward filter (FFF) to filter a second tentative decision of an adjacent receiver; a subtractor to compute the difference of the output of the first FFF from the output of the first summer to compute a first FEXT-free output signal; a second decision device, comprising a second modulo device and a second slicer, to process the first FEXT-free signal to compute a first output symbol. ### Claim 2 (depends on 1) The far-end cross-talk canceller in claim 1 where the first tentative decision is input to a second feed-forward filter (FFF) of an adjacent receiver. ### Claim 3 (depends on 1) The far-end cross-talk canceller in claim 1 where the precoder is a Tomlinson-Harashima precoder. ### Claim 4 (depends on 1) The far-end cross-talk canceller in claim 1 where the first tentative decision is computed by adding the output of the first summer to a first error signal obtained by computing the difference between the input and output of a first slicer of the first decision device. ### Claim 5 (depends on 4) The far-end cross-talk canceller in claim 4 where the first slicer is coupled to the output of a modulo device whose input is coupled to the output of the first summer. ### Claim 6 (depends on 1) The far-end cross-talk canceller in claim 1 where the first tentative decision is filtered by a precoder filter first and the filtered output is input to the second feed-forward filter (FFF) of an adjacent receiver. ### Claim 7 (depends on 6) The far-end cross-talk canceller in claim 6 where the precoder filter is an infinite impulse response filter. ### Claim 8 (depends on 1) The far-end cross-talk canceller in claim 1 where a second error signal across a second slicer of a second decision device coupled to the first FEXT-free signal is used to adapt the second feed-forward filter (FFF) of an adjacent receiver. ### Claim 9 (depends on 1) The far-end cross-talk canceller in claim 1 used in a wireless Ethernet transceiver. ### Claim 10 (depends on 1) The far-end cross-talk canceller in claim 1 integrated by a circuit. ### Claim 11 (depends on 1) The far-end cross-talk canceller in claim 1 used in a communications transceiver containing a first receiver, where the first received signal corresponds to a signal after echo from its near-end transmitter has been cancelled from its input signal. ### Claim 12 (depends on 1) The far-end cross-talk canceller in claim 1 used in a communications transceiver containing a first receiver, where the first received signal corresponds to a signal after near-end cross-talk from an adjacent transmitter has been cancelled from its input signal. ### Claim 13 An integrated circuit to implement a far-end cross-talk (FEXT) canceller for a precoded multiple-input multiple-output communications system comprising a plurality of receivers, each receiver comprising: a first feed-forward equalizer (FFE) to process a first received signal, a second feed-forward equalizer (FFE) to process a second received signal, and a first summer to sum the outputs of the first and second FFE; a first-decision device, comprising a first modulo device and a first slicer to process the output of the first summer to generate a first tentative decision; a first feed-forward filter (FFF) to filter a second tentative decision of an adjacent receiver; a subtractor to compute the difference of the output of the first FFF from the output of the first summer to compute a first FEXT-free output signal; a second decision device, comprising a second modulo device and a second slicer, to process the first FEXT-free signal to compute a first output symbol. ### Claim 14 (depends on 13) The FEXT canceller integrated circuit in claim 13 where the first tentative decision is input to a second feed-forward filter (FFF) of an adjacent receiver. ### Claim 15 (depends on 13) The FEXT canceller integrated circuit in claim 13 where the precoder is a Tomlinson-Harashima precoder. ### Claim 16 (depends on 13) The FEXT canceller integrated circuit in claim 13 where the first tentative decision is computed by a second summer to add the output of the first summer to a first error signal obtained by a subtractor that computes the difference between the input and output of a first slicer of the first decision device. ### Claim 17 (depends on 13) The FEXT canceller integrated circuit in claim 13 where the first slicer is coupled to the output of a modulo device whose input is coupled to the output of the first summer. ### Claim 18 (depends on 13) The FEXT canceller integrated circuit in claim 13 where the first tentative decision is filtered by a precoder filter first and the filtered output is input to the second fed-forward filter (FFF) of an adjacent receiver. ### Claim 19 (depends on 18) The FEXT integrated circuit in claim 18 where the precoder filter is an infinite impulse response filter. ### Claim 20 (depends on 13) The FEXT canceller integrated circuit in claim 13 where a second error signal across a second slicer of a second decision device coupled to the first FEXT-free signal is used to adapt the second feed-forward filter (FFF) of an adjacent receiver. ### Claim 21 (depends on 13) The FEXT canceller integrated circuit in claim 13 used in a wireless Ethernet transceiver. ### Claim 22 (depends on 13) The FEXT canceller integrated circuit in claim 13 used in a communications transceiver containing a first receiver, where the first received signal corresponds to a signal after echo from its corresponding near-end transmitter has been cancelled from its input signal. ### Claim 23 (depends on 13) The far-end cross-talk canceller integrated circuit in claim 13 used in a communications transceiver containing a first receiver, where the first received signal corresponds to a signal after near-end cross-talk from an adjacent transmitter has been cancelled from its input signal.