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It is a practical challenge for wireless communication system designs to achieve both high spectral efficiency and energy efficiency because of the nonlinear effect and inefficiency of power amplifier. In previous work, the power amplifier efficiency is always considered as a constant, but it changes with the output power in reality. In this paper, we talk about the impact of variable power amplifier...
The explosive growth of the data traffic demands in cellular network has present more challenges. As the link efficiency is approaching its fundamental limitation, we can only increase the node deploy density to achieve satisfying network capacity. 3 GPP focus on Pico-cell overlaid HetNet, in which small cell base stations (pico eNB: pico evolved Node-B) with low transmit power are deployed at the...
Blind multiuser detector can efficiently suppress multiple access interference (MAI) in code-division multiple access (CDMA) system, with prior knowledge of only the signature sequence and timing of the desired user. For the Tikhonov blind multiuser detector, theoretical performance analysis has not been given, which is more convincing. We gave analytical performance in this paper, with the output...
In this paper, the effect of the imperfect channel stated information (CSI) on the system performance of the radio resource management is investigated for the uplink transmission in multi-user CDMA systems. The imperfect CSI introduces the constellation-point dependent symbol error rate (SER), which correspondingly yields the nonconvex and nondifferentiable throughput function. Then, a bisection based...
This paper aims at the problem of large amounts of realtime data transmission in indoor WLAN positioning. We propose a method that we use the BP network to compress at the sending end, and then save the weight. The method reconstructs data in the terminal, which greatly reduces the amount of data in real-time transmission to ensure the fast and effective of real-time positioning. The used simulation...
By learning property of human fingerprint in bioinformatics, we used SURF to extract frames' features and handle them by visual vocabulary and word frequency analysis. Videos can be represented uniquely in this way. Based on the theory of image sparse coding in mammal's visual system, we used standard library to train sparse dictionary which could encode SURF features of frames. By dealing with nonzero...
Seismic images are collected by seismic sensors. Containing the geological information of geological structures such as strata and crater, these images are of high significance. However, due to the complexity of their backgrounds, edges of structures to be studied appear blurry. This paper proposes a method to enhance the strata and crater structures using morphology. Opening and closing operations...
Wireless broadcasting systems employ multiple retransmissions to guarantee the correct reception of each packet. Traditional hybrid automatic retransmission request (HARQ) protocol retransmits one packet per slot. Hence, a large amount of retransmissions are required to correctly receive all the packets, which lead to low spectrum efficiency. In this paper, we propose a Max-Degree Network Coding (MDNC)...
An analysis for wideband spectrum sensing of many primary users active in cognitive radios has been presented. The spectrum holes occur while all the signals in wide band are detected and separated. This paper focuses on the multi-signals separation problem while the signal number is uncertain and the noise floor spectrum is non-flat. The wideband spectrum is recursively divided into smaller scale...
Millimeter wave communication is a main solution for the high speed backhaul and ultra-high speed access transmission. This paper presented the interface-aware LDPC codes in the millimeter-wave system to support highspeed Ethernet interfaces and reduce the conversion delay. Considering constraints of the encoded codeword length of 1 G to 100 G Ethernet physical layer, LDPC (196, 120), LDPC (588, 528),...
Lots of information is missing in poor communication environment and the data receiving terminal cannot recover source data, therefore, this paper proposed a new anti-jamming method of spread-spectrum communication based on LT codes. This method uses the characteristics of information scattered encoding and non-rate transmission of LT codes, through the spectrum of the signals which is the direct...
A new digital differentiator-based demodulator in a zeroIF receiver for 2.4 GHz Zigbee applications is proposed. It receives the In-phase (I) and Quadrature-phase (Q) signals which are oversampled and quantized by a 4-bit ADC @ 8 MHz. Two one-order digital differentiators based on Taylor series, two multipliers and an adder are adopted to calculate the derivative of the signal phase. Then an Integrate-and-Dump...
In digital signal processing, it is difficult to achieve flexible arbitrary sampling rate conversion. As for this problem, a new algorithm is proposed to realize arbitrary variable up-sampling based on lookup table. The algorithm firstly constructs an original filter whose coefficients are stored in ROMs. Then the target filter is decimated from lookup table by mapping sampling rate as addressed....
HHVBF routing protocol is studied based on the location information and a Reliable HHVBF (RHHVBF) routing protocol is proposed in this paper. RHHVBF ensures the reliability of the entire link by ensuring the transmission reliability of each hop among the path from the source node to the destination node. We propose Node by Node Channel Evaluation Model (NNCEM) to evaluate the link between nodes, based...
Obtaining the accurate estimation of available bandwidth is precondition of QoS-guaranteed. In this paper, we proposed a novel available bandwidth estimation mechanism in 802.11 RTS/CTS by correct measurements of 1) a new coefficient, called channel utilization ratio, which considering the QoS of realtime multimedia, 2) overhead by the control messaging. Simulation result shows that taking the channel...
Due to the limited energy of the nodes in opportunistic sensor networks, and connectivity parameters in the process of collecting, processing, transmission have the features of information redundancy, this paper proposed DFMW (Data Fusion Mechanism based on Wavelet for Opportunistic Sensor Networks). DFMW, compresses the parameters by HFCSA (High Frequency Coefficients Selected Algorithm), which excludes...
In this paper, a priority-based bandwidth allocation in the context of heterogeneous wireless network is studied. By utilizing the mobile terminals with multi-homing capability, which simultaneously accesses bandwidth from different wireless network, a novel utility-based bandwidth allocation approach is introduced. An essential factor is the priority mechanism considering the services priority classification,...
This paper investigates the Dynamic Subcarrier Allocation (DSA) issue in Long Term Evaluation (LTE) uplink. Many researches pay more attention on maximizing the system throughput or improving the fairness between multi-users, however, they ignored the user actual spectrum demand. In this paper, an improved subcarrier allocation scheme has been proposed, which considers the user demand of quality of...
The problem of channel estimation in multi-cell massive MIMO systems is addressed in this paper. The channels observed different antennas in the same cell have approximately sparsity and common support, and the sparsity and common support properties draw more and more attentions when it comes to the efficient estimation of large number of channels in massive MIMO systems. The short channel coherence...
Visible light communication (VLC) is regarded as an emerging wireless access technology that has tremendous potential for 5G. However, the link of VLC is vulnerable to blockage of moving objects within the room. Moreover, the link data rate of VLC falls sharply with link distance increasing. Therefore, VLC needs to constitute networks with other wireless technologies, such as WiFi, WiMAX, 2G/3G and...
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