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The emerging of millimeter wave (mmWave) communications has been widely predicted to revolutionize the traditional communications. On one hand, the large bandwidth provided by mmWave is orders of magnitudes larger than that provided by current microwave communications, which therefore supports much higher throughput as well as massive connectivity. On the other hand, the small wavelength of mmWave...
With the development of wireless transmission technology, the coexistence of a variety of network protocols is inevitable in industrial control networks for a certain period of time. Due to the lack of a necessary coordination mechanism between different network protocols, this may impact the transmission performance of the backhaul network connecting several subnetworks with different protocols when...
In this paper, we demonstrated a passively mode-locked erbium-doped fiber laser by incorporating a microfiber-based tungsten diselenide (WSe2) saturable absorber (SA). We obtained stable mode-locking with pulse duration of 1.2 ps, repetition rate of 2.6 MHz and signal-to-noise ratio (SNR) of 66 dB at maximum pump power of 400 mW. The experimental results show that CVD-grown WSe2 film can serve as...
We report, for the first time to our knowledge, the usage of CVD-grown few-layer WSe2 as a saturable absorber for the mode locking of a thulium-doped fiber laser. The WSe2 saturable absorber was deposited on the waist of the tapered fiber. By employing the WSe2 saturable absorber, we demonstrate a passively mode-locked fiber laser operating at 1863.96 nm with a 3 dB spectral bandwidth of 2.89 nm....
Spatial modulation (SM) is proposed to both achieve a high energy efficiency (EE) and low implementation complexity, which attracts a lot of academic interests. Generalised SM (GenSM) is proposed to achieve a higher spectral efficiency (SE) than traditional SM system, and there are many researches about detection in GenSM system. In this paper, we propose a novel low-complexity detection algorithm...
In this paper, a spectral efficient channel estimation scheme is proposed for spatial-correlated sparse massive multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems with superimposed time-frequency training sequences (TSs) based on basis expansion model (BEM). This scheme first relies on the identical time-domain TS to acquire the partial channel common support,...
In spatial modulation (SM) systems, the distribution of amplitude-phase modulation (APM) symbol causes the tradeoff of detection performance between APM symbol and active antenna, which infers the overall capacity of SM system. In this paper, the APM constellation and symbol labeling of SM system is investigated. The optimized APM constellation is designed to maximize the system coded modulation average...
The non-orthogonal multiple access (NOMA) technology has been proposed and regarded as one of the potential promising technologies for the future 5G network. The extension of generalized spatial modulation multiple-input multiple-output (MIMO) to NOMA system improves both the spectral and energy efficiencies of the system, while maintaining the massive connectivity and low latency advantages, but...
Combined with client pairing on nonorthogonal multiple access (CP-NOMA), carrier sense multiple access/collision avoidance (CSMA/CA) can provide more connectivity for clients in downlink phase and alleviate the low transmission efficiency from rate anomaly problem. Compared with conventional CSMA/CA system, the proposed enhanced CSMA/CA with CP-NOMA can save about half of the time cost to send signaling...
In this paper, we propose a new method in which the recently proposed non-orthogonal multiple access (NOMA) is combined with the conventional Alamouti scheme. The developed analytical results and simulation both show that if the targeted data rates and the allocated power satisfy an inequality constraint, then our proposed method can effectively increase the diversity order of NOMA from 1 to 2, the...
Combining Spatial Modulation (SM) with multiple-input multiple-output (MIMO) systems constitutes a promising technique for exploiting full spatial multiplexing. To further maximize its capacity, we propose to optimize the activation probability with an iternative optimization method. Moreover, we propose to incorporate the newly-proposed distribution matcher encoder for probability shaping. Numerical...
Flat-fading channel models are usually invoked for analyzing the performance of massive spatial modulation multiple-input multiple-output (SM-MIMO) systems. However, in the context of broadband SM transmission, the severe inter-symbol-interference (ISI) caused by the frequency-selective fading channels can not be ignored, which leads to very detrimental effects on the achievable system performance,...
Channel estimation for underwater acoustic (UWA) channels in orthogonal frequency division multiplexing (OFDM) systems is one of the most difficult problems in UWA communications. Because UWA channels are both frequency-selective and time-selective, the total number of channel coefficients to be estimated will significantly increase. Besides, the fast time-varying characteristics and strong Doppler...
In generalised spatial modulation (GenSM) systems, the total number of active antenna groups is always not a power of two, which leaves room for designing an active antenna group (AAG) selection algorithm to achieve the constellation shaping gain and to improve the symbol error rate (SER). In this paper, based on uniform-cost search, a novel iterative AAG selection algorithm for GenSM systems is proposed...
In order to solve the problem of fuzzy details, low contrast and poor visual effect of infrared image. A novel scheme for infrared image enhancement is proposed in this paper, which solved drawbacks of the histogram equalization algorithm that loss detail information of image and some areas are bleached, greatly improved the visual effect of the infrared image. Firstly, bilateral filter is performed...
For measurement of micro liquid volume, researchers are mainly using the gravimetric method. The volume of liquid is obtained by measuring the mass density of liquid. ISO 8655 proposed the non-gravimetric method based on photometric method, which makes the method for measuring micro liquid volume become a new trend of development. In order to meet the requirements of online measurement, and overcome...
LDS-OFDM and SCMA are two examples of non orthogonal multiple access (NOMA), which is considered to be a promising technology for next generation wireless communications due to its larger capacity region compared with orthogonal multiple access (OMA). Iterative receiver structure is used in these two systems to get better performance than the noniterative receiver, but a direct implementation of iterative...
The idea of combining spatial modulation (SM) with massive multiple-input multiple-output (MIMO) system, i.e. massive SM-MIMO, has recently attracted plenty of academic interest, as it could simultaneously harness the advantages of SM and massive MIMO. However, the spectral efficiency (SE) analysis for massive SM-MIMO is still lack of exploring. To this end, a novel SE expression is derived in this...
The liquid volume is an important metrology method for commercial transaction in international trade, and the vertical tank is used as main metrology tool. One non-contact optical measurement system was raised by using laser scanning method. The coordinates of vertical tank shell were acquired by phase-shift ranging method and angular measurement, and the set of coordinates is named as data cloud...
In order to overcome the shortcoming that influences of evaporation capacity on the gravimetric method, and meet the requirement of online measurement, a non-gravimetric method is introduced for measuring micro liquid volume. According to Faraday's law and Karl Fischer electrochemical principle, the Karl Fischer potentiometric titration method (KFCT method) is also investigated for micro liquid volume...
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