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THE STUDY OF AN M-ARY MC-CDMA SYSTEM BASED ON CYCLIC SPREADING CODES & PRE-EQUALIZATION
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作者 ChuZhenyong YingXiaofan +1 位作者 YiKechu TianHongxin 《Journal of Electronics(China)》 2005年第3期273-280,共8页
A novel fast despreading scheme for M-ary Multi-Carrier Code-Division Multiple Access (MC-CDMA) system is proposed based on cyclic spreading codes and pre-equalizer. In the transmitter, the M spreading codes of each u... A novel fast despreading scheme for M-ary Multi-Carrier Code-Division Multiple Access (MC-CDMA) system is proposed based on cyclic spreading codes and pre-equalizer. In the transmitter, the M spreading codes of each user are generated by circularly shifting the prototype spreading code. A feedback pre-equalizer is employed to process the M-ary MC- CDMA signal before transmitted. The received signal is multiplied by the Inverse Discrete Fourier Transform (IDFT) result of the mirror image code of the prototype spreading code, and then demodulated by Orthogonal Frequency-Division Multiplexing (OFDM) demodulator. Compared with the conventional M-ary MC-CDMA receiver, the proposed scheme increases bandwidth efficiency, meanwhile, it achieves M-ary despread spectrum and multi-carrier demodulation, which reduces computation complexity remarkably. 展开更多
关键词 Multi-Carrier Code-Division Multiple Access (MC-CDMA) M-ary spread spec- trum Cyclic spreading codes pre-equALIZATION Computation complexity
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100 Gbit/s Nyquist-WDM PDM 16-QAM Transmission over 1200 km SMF-28 with Ultrahigh Spectrum Efficiency
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作者 Ze Dong 《ZTE Communications》 2012年第3期22-27,共6页
Nyquist wavelength-division multiplexing (N-WDM) allows high spectral efficiency (SE) in long-haul transmission systems. Compared to polarization-division multiplexing quadrature phase-shift keying (PDM-QPSK), m... Nyquist wavelength-division multiplexing (N-WDM) allows high spectral efficiency (SE) in long-haul transmission systems. Compared to polarization-division multiplexing quadrature phase-shift keying (PDM-QPSK), multilevel modulation, such as PDM 16 quadrature-amplitude modulation (16-QAM), is much more sensitive to intrachannel noise and interchannel linear crosstalk caused by N-WDM. We experimentally generate and transmit a 6 x 128 Gbit/s N-WDM PDM 16-QAM signal over 1200 km single-mode fiber (SMF)-28 with amplification provided by an erbium-doped fiber amplifier (EDFA) only. The net SE is 7.47 bit/s/Hz, which to the best of our knowledge is the highest SE for a signal with a bit rate beyond 100 Gbit/s using the PDM 16-QAM. Such SE was achieved by DSP pre-equalization of transmitter-side impairments and DSP post-equalization of channel and receiver-side impairments. Nyquist-band can be used in pre-equalization to enhance the tolerance of PDM 16-QAM to aggressive spectral shaping. The bit-error ratio (BER) for each of the 6 channels is smaller than the forward error correction (FEC) limit of 3.8 × 10-3 after 1200 km SMF-28 transmission. 展开更多
关键词 16-QAM coherent detection Nyquist wavelength-division multiplexing Nyquist-band pre-equALIZATION spectral efficiency signaltransmission
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Novel pre-equalization transimpedance amplifier for 10 Gb/s optical interconnects 被引量:1
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作者 宋奇伟 毛陆虹 +1 位作者 谢生 康玉琢 《Journal of Semiconductors》 EI CAS CSCD 2015年第7期114-118,共5页
This paper presents a modified regulated cascode (RGC) transimpedance amplifier (TIA) with a novel pre-equalized technique. The pre-equalized circuit employed the broadband series inductive Jr-network and Gin- boo... This paper presents a modified regulated cascode (RGC) transimpedance amplifier (TIA) with a novel pre-equalized technique. The pre-equalized circuit employed the broadband series inductive Jr-network and Gin- boosting technique. The introduction of this technique compensates the transferred signal at the input port of the TIA without an increase in power dissipation. Furthermore, a novel miller capacitance degeneration method is designed in the gain stage for further bandwidth improvement. The TIA is realized in UMC 0.18 μm CMOS technology and tested with an on-chip 0.3 pF capacitor to emulate a photodetector (PD). The measured transimpedance gain amounts to 57 dBf2 with a -3 dB bandwidth of about 8.2 GHz and consumes only 22 mW power from a single 1.8 V supply. 展开更多
关键词 pre-equalized Gm-boosting series inductive re-network miller capacitance degeneration
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