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Cupertino, CA, United States

Yu J.,NEC Laboratories America Inc.
Electronics Letters | Year: 2010

A 1.2Tbit/s orthogonal DWDM optical signal with 12 orthogonal subchannels held in 300GHz frequency spacing has been successfully generated. Each subchannel is 100Gbit/s PD-RZ-QPSK signal and held at 25GHz spacing. The optical signal-to-noise ratio requirement at a bit error ratio of 2×10 -3 for each subchannel is not higher than 17dB. After transmission over 1040km standard singlemode fibre with pure EDFA application, 80km amplifier span and no dispersion compensation fibre, the BER for all subchannels is smaller than 1.2×10-3. © 2010 The Institution of Engineering and Technology.

Ip E.,NEC Laboratories America Inc.
IEEE Photonics Technology Letters | Year: 2012

We investigate gain equalization in few-mode fibers supporting more than two-mode groups at the signal wavelengths and find that a combination of pump control and doping profile optimization is required to equalize mode-dependent gain. © 2012 IEEE.

Ip E.,NEC Laboratories America Inc.
Journal of Lightwave Technology | Year: 2010

Digital backpropagation (BP) is a universal method for jointly compensating dispersion and nonlinear impairments in optical fiber and is applicable to signals of any modulation format. In this paper, we compare single carrier (SC) versus orthogonal frequency-division multiplexing (OFDM) for polarization-multiplexed transmission. We show that at realistic data rates and transmission distances, polarization mode dispersion does not significantly degrade the performance of BP and can be mitigated by a post-BP linear equalizer. Dispersion unmanaged transmission can significantly reduce nonlinearity, and in this transmission regime, SC and OFDM have similar nonlinear tolerance. Multichannel BP is effective at mitigating interchannel nonlinearity for point-to-point links. © 2010 IEEE.

NEC Laboratories America Inc. | Date: 2015-08-28

A system and method for resource management in a heterogeneous wireless network that is performed via distributed implementation wherein the resources of the mobile communications system are managed on a coarse time-scale and a fine time-scale. The coarse time-scale management comprises a first stage of determining the user association for each of the TPs followed by a second stage of determining activation fractions for all TPs. The determining of the user association is performed by utilizing a GLS procedure having a Greedy Stage and a Local Search Stage. In the Greedy Stage, new user, TP pairs are analyzed and the pair with the greatest improvement in system utility is selected. In the Local Search Stage, potential swaps are analyzed and a pair offering the greatest improvement that exceeds a threshold is selected. The determining of activation fractions for all TPs is performed by utilizing an auxiliary function method.

NEC Laboratories America Inc. | Date: 2015-04-10

The invention uses a point-to-multi-point (P2MP) discovery process conducted in a passive optical network PON system to identify each sensor that returns a probe pulse identified with a respective sensor without adding any equipment at the remote sensors. The sensors provide with the returned signal information indicative of measured gas leakage in the air in the sensor.

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