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10+Gbps serial data transmission over a Tyco 34' FR4 backplane channel using amplitude-optimized bit-edge equalization with an adjustment of LMS error derivation points

Posted on:2011-07-16Degree:Ph.DType:Dissertation
University:Carleton University (Canada)Candidate:Zhang, LeiFull Text:PDF
GTID:1448390002462744Subject:Engineering
Abstract/Summary:
In high-speed backplane serial data transmission systems, channel impairments such as amplitude attenuation and group-delay distortion cause intersymbol interference (ISI) that limits the maximum transmission distance and data rate. This dissertation presents a unique amplitude-optimized bit-edge equalization (BEE) scheme for 10+Gbps serial data transmission over high-loss backplane channels. The proposed BEE scheme intends to mitigate ISI and reduce the impact of channel group delay distortion by compressing data spectrum in conjunction with optimizing the sampling phase. Using a least-mean-square (LMS) adaptive algorithm as a receiver (RX) error convergence engine, the proposed BEE scheme aims to optimize the bit-edge amplitudes by equalizing only the edges of data bits with an adjustment of the LMS error derivation points, which in turn changes the error information and affects filter coefficients for pulse amplitude modulation. Thus, the proposed amplitude-optimized BEE eliminates the need for complicated algorithms that are required in the phase-optimized BEE.;In this research, a typical Tyco 34" FR4 backplane channel was used as the comparison benchmark. A Matlab script was generated and used to evaluate the link performance when comparing various channel equalization and signaling techniques. The optimality of using the proposed BEE in channel efficiency, signal-to-noise ratio (SNR) enhancement, power constriction, as well as mitigating ISI and reducing the impact of channel group delay distortion was demonstrated and compared with those by using the phase-optimized pulse width modulation (PWM) and the conventional non-retum-to-zero bit-center equalization (BCE) and duobinary signaling schemes.;It was demonstrated that, using the proposed BEE as TX pre-emphasis at a 12Gbps data rate, the channel's far-end bit-edge (BE) eye was enlarged by approximately 88.9% in eye height and 20.8% in eye width compared to the bit-center (BC) eye when using the conventional BCE scheme. In addition, the BE eye using the proposed BEE was enlarged by approximately 143% in eye height and 16.6% in eye width compared to the eye height and width when using the conventional duobinary signaling scheme.;It was also demonstrated that, by using the proposed BEE as the TX de-emphasis at a 10Gbps data rate, the channel's far-end bit-edge eye height was enlarged by approximately 77.5% with a 0.93% reduction in eye width compared to the bit-center eye when using the conventional BCE. In addition, the bit-edge eye height using the proposed BEE was enlarged by approximately 29.1% with a 5.8% reduction in eye width compared to the eye height and width when using the phase-optimized PWM.;This proposed BEE scheme employs a 5-post-tap symbol-spaced FIR (SSF) filter as the transmitter (TX) pre-emphasis/de-emphasis for bit-edge equalization. With TX data pre-coding, the channel's far-end 3-level signal to 2-level binary decoding depends only on the current received bit. No error propagation occurs.;It is concluded that the proposed BEE scheme has better performance for high speed (e.g. 10Gbps and exceed) data transmission over high loss channels.
Keywords/Search Tags:Data, Channel, Proposed BEE, Backplane, Bit-edge, LMS, Error, Eye
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