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Bit error rate (BER) performances of DPSK are researched for space uplink optical communication system. Considering further phase fluctuation effect based on the traditional atmospheric turbulence model, BER performance versus transmission power, zenith angle, frequency deviation, divergence angle and transmission diameter are discussed for different wavelengths. Simulations, especially, indicate...
The channel impulse response (CIR) under indoor stair environment is modeled. In this model, the amplitude and phase of the CIRs are described as Weibull and uniform distributed random variables, respectively. The CIRs can be simulated using the proposed model. Then, Orthogonal Frequency Division Multiplexing (OFDM) communication system is implemented on the measured and simulated channels. Based...
We demonstrate BPSK modulation using a silicon traveling-wave modulator at data rate up to 48 Gb/s, with 7.4 Vpp differential RF driving voltage. The performance of the silicon BPSK modulator is compared with a commercial Lithium Niobate phase modulator, showing better dispersion tolerance.
In this paper, a novel joint recursive least square (RLS) and least mean square (LMS) adaptive equalization algorithm for indoor, short range wireless communications under staircase environment is proposed. In this algorithm, the RLS is initially used to realize the fast convergence. Then, the LMS is adapted to rapidly optimize the receiving signals. Once the imbalance of the equalizer or severe channel...
With the development of communication technique, space microwave communication technique has shown its limitation in the transmission of high data rate. While space optical communication system introduces laser as the signal carrier and can solve this problem very well. At present, on-off keying (OOK) is one of the most important modulation scheme widely used in space optical communication systems,...
The space optical communication system, which is hopeful to be the key technique of the next generation of space communication system, owns better security and faster transmission rate. At present, on-off keying (OOK) modulation scheme is widely used in practical optical communication systems. However, few people pay attention to the investigation of the performance of communication system based on...
In view of the defects that low data transmission rate in integrated radar-communication system based on Linear Frequency Modulation (LFM), and integrated radar-communication system based on Orthogonal Frequency Division Multiplexing (OFDM) is sensitive to frequency shift, its orthogonality of subcarriers is also easily broken. For those problems, this paper presents a novel integrated radar-communication...
Multiple Input Multiple Output (MIMO) system is considered as an unalterable technology in wireless communication for its advantages in the spectral efficiency. Among the detection algorithms, maximum likelihood (ML) detection can achieve the best bit error rate performance, but the computational complexity of ML detection is too huge to be acceptable. In order to solve this problem, numbers of algorithms...
We proposed and demonstrated a hybrid fiber amplifier. It is composed of a C-band erbium-doped fiber amplifier EDFA) and an L-band Raman fiber amplifier (RFA) using double-pass dispersion compensators in a loop-back scheme. Dispersion slope mismatch is compensated precisely for all C+L band channels by writing fiber Bragg gratings (FBGs) at appropriate locations. Gain variation among multiple channels...
In the paper, a new distributed coding scheme for parallel relay systems is proposed, in which a sender communicates to a destination that is two hops away via two (or more) parallel relays. The key idea is the exploitation of a (rate-1) soft convolutional encoder at each of the parallel relays, to collaboratively form a simple but powerful distributed analog coding scheme to achieve efficient forwarding...
Reconciliation protocol is used in quantum key distribution to reverse the error bits. Cascade is the most famous reconciliation protocol. It uses BINARY to correct errors and traces back into history records to find another error. In this paper, we implement the Cascade protocol and carry out some experiments for different BER, where BER is bit error rate for qubits. From the result of experiments,...
In order to support applications with different Quality-of-Service (QoS) requirements in Multimedia communication, this paper designs and investigates a kind of high rate unequal diversity (HRUD) code based on the quasi-orthogonal spacetime block code (QO-STBC) for transmission. This code can achieve high rate, and also provide unequal error protection for multiple layers simultaneously. When transmit...
MIMO (Multiple-Input-Multiple-Output) is a promising structure for wireless communication. While virtual MIMO structure has been proposed for distributed and cooperative wireless networks, this proposed structure has also put additional energy consumption where energy stands in the important position. At the same time, we have observed that this-problem-caused low energy nodes' mibehavior will degrade...
Marine radio-navigation system is based on spread spectrum system, whose working environment is complexity and usually works in a bad channel conditions. Strong sky-wave interference in the system affected the positioning accuracy seriously. Sky-wave is a typical fast time-varying signal with large range of amplitude and rapid changing. The general multi-user detection algorithm can not effectively...
Constellation labeling is an one-to-one mapping relationship associating 0–1 bit sequences and signal points. Different constellation labeling results in different bit error rate (BER) performance. Some works have certified that the Binary Reflected Gray Code for M-PAM, M-PSK and M-QAM can give the lowest possible average BER. But there are few works considering about the best labeling for other specially...
DSTBC (differential space-time block coding) system does not require CSI (channel state information) in both transmitter and receiver sides, but its SNR (signal to noise ratio) versus BER (bit error rate) characteristic is degraded compared with original STBC scheme which utilizes CSI at the receiver. In this paper, attempting to recover this performance loss originated from the differential decoding,...
In this paper, a typical commercial short range wireless communication module which has weak immunity to interference has been tested and its performance has been evaluated with test bed. An adaptive frequency hopping scheme has been proposed to improve its immunity to interference and therefore enhance the wireless communication performance for reliability and delay-critical applications. Such scheme...
In order to increase the performance of joint channel estimation and decoding through belief propagation on factor graphs, we approximate the distribution of channel estimate in the factor graph as a mixture of Gaussian distributions. The result is a continuous downward and upward message propagation in the factor graph instead of discrete probability distributions. Using continuous downward messages,...
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