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Ultra-wideband (UWB) indoor channel characteristics which incorporate human body effects are analyzed. Channel impulse responses (CIRs) are measured in the frequency band of 3 GHz to 4.6 GHz in four different classrooms. For each measurement site, the proportion of occupied seats is changed to observe the effect of the number of people on the wireless propagation channel. First, path-loss exponents...
A multiple-layer-overlay (MLO) modulation format is employed for a 14-km optical fiber link and an enhanced spectral efficiency of 2.36 bits/s/Hz is achieved by multiplexing 3-layer signals with each layer carrying a 2-Gbit/s QPSK signal.
We report a transmission of 3 Gbit/s signal over a 4-km grade-index multimode fiber within a bandwidth of 2.54 GHz using multiple-layer-overlay (MLO) modulation format, achieving a spectral efficiency of 1.18 symbols/s/Hz.
We present a silicon modulator with a measured E-O bandwidth of 41 GHz at −4 V bias. Open eye diagrams are visible up to 60 Gbps. With DSP, 112 Gbps PAM-4 transmission below FEC threshold is demonstrated.
We evaluated wideband 25 Gbps error-free operation of Si slow light modulators. The fluctuation in extinction ratio was 1 dB over the bandwidth. Larger group indices produce larger extinction ratios and lower bit error rates.
The bandwidth capacity of 50/125 µm multimode fiber is extended by using four VCSELs with wavelengths coarsely separated at 30nm and with each wavelength operating at 40Gb/s. All four wavelengths achieve BER <1E–12 at 100m.
A multi-band CAP system is experimentally demonstrated for the first time in VLC. We show that with an 8-CAP testbed spectral efficiencies (∼4.75 b/s/Hz) at a realistic distance of 1 m can be reached.
We demonstrate WDM transmission of 75-Gbaud PDM-16QAM signals over 1,920 km. InP-based high-speed and compact MUX-DAC integrated modules (bandwidth exceeds 40 GHz) enable the long haul transport of 1-Tb/s superchannels composed of just two subcarriers.
We demonstrate a single-fiber low-cost 1.25 Gb/s transceiver able to switch between transmission and reception mode. Crosstalk suppression with <1dB penalty is achieved through filtered reception mode for WDM-loaded power-splitting PONs with >20dB optical budget.
The time domain hybrid QAM enabled flexible transceiver is proposed to adaptively optimize the transmission performance in DWDM systems with cascaded ROADMs. Comprehensive performance investigations are conducted for both fixed and flexible grid systems.
A 10-GHz TO-can packaged colorless laser diode under coherent injection-locking for 42-Gbit/s 64-QAM OFDM transmission over 25-km SMF is demonstrated to achieve the lowest BER of 4.2×10−4 at a receiving power of −2 dBm.
This paper presents a bandwidth-efficient transmission scheme where several signals are sent simultaneously. To allow users’ differentiation at the receiver (s), each user data sequence is first multiplied by a specific amplitude sequence prior to being sent through the channel. In addition, the proposed scheme uses error correcting codes and soft-decision demodulation to reduce residual multi-user...
Carrier aggregation (CA) is a technique introduced in LTE-Advanced to achieve a higher throughput by increasing bandwidth. In this work, the spectrally efficient frequency division multiplexing (SEFDM) bandwidth compression technique is utilized to enhance CA performance. This work reports experimental demonstration of SEFDM and shows that up to 7 component carriers (CCs) can be aggregated in a given...
We review recent single-carrier 400G schemes based on high baud rate signals with different spectrum efficiency (SE) based on QPSK and 16QAM. The long-haul performances under different transmission conditions and modulation formats are studied. The digital signal processing for 400G signal recovery is also discussed.
In this paper, we experimentally investigate the effect of state-of-the-art digital to analog converter (DAC) circuit, on the performance of high speed optical transmitter. We particularly consider two operating regimes, we refers as over- and under-sampling conditions. It is well known that a sampling rate of 64GSa/s limits the maximum baud rate to 32Gbaud with a sampling rate of 2 sample/symbol...
We proposed to implement a VLC technology for portable FLCOS-based projector application. A FLCOS-based projector using RGB-based LEDs has designed and simulated. A RGB-based LEDs VLC link has investigated and the initial results using a reconfigurable design of a 1st order RC pre-equalizer has demonstrated that the entire system modulation bandwidth can be improved from 35MHz to 79.2MHz. Data transmission...
We have experimentally implemented a short-range visible light communication system based on the use of RGB-based LED which has widely employed as the light source in portable device for micro-projection application. The entire system modulation bandwidth with the use of a designed 1st order RC post-equalizer has improved from 35MHz to 188.5MHz. Data transmission tests using OOK modulation scheme...
Orthogonal Frequency Division Multiplexing (OFDM) is the preferred modulation scheme for current and future broadband wireless systems, and has been incorporated in many standards. In spite of its many benefits, which include robust performance in noise, fading channels and uncorrelated interference, OFDM systems have poor performance in the presence of jamming. In this paper we study the use of sub-band...
The United States Department of Defense and researchers throughout the world have been addressing the overcrowding of the radio frequency (RF) spectrum. This has led to numerous studies concerning cognitive radios, networks, and radar systems. In this paper we demonstrate the possibility of sending both analog voice and digital signals simultaneously using legacy analog radios without appreciably...
A real demand for underwater acoustic (UWA) communications exists in oceanography, ocean exploration and undersea navigation. A new Doppler resilient digital communication, based on quadratic frequency modulations (QFM) is presented. The binary information is transmitted using two orthogonal QFM chirps. This signal modulation is suitable for low-data-rate communication such as telemetry. The first...
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