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To make full use of the characteristics of LDPC decoding, Stephan ten Brink had proposed a joint iterative demapping and decoding algorithm for LDPC coded BICM systems. Based on Brink proposed algorithm, we propose a modified joint iterative scheme to further reduce the computation complex. Different from the algorithm presented by Brink, in the process of iterative demapping and decoding, the proposed...
A decision-feedback equalizer (DFE) for Multi-h CPM in aeronautical telemetry is presented in this paper. This algorithm estimates the inter-symbol interference and cancels it from the samples used to make the bit decisions. The approach improves the bit estimates sequentially, thereby increasing the probability of obtaining accurate estimates. Simulation results show an 1 dB improvement in bit error...
BPSK interference is also called the matched spectrum interference, because its wave form and frequency coverage matches that of satellite navigation signal. As efficient wideband interference, it heavily menaces the safety of Global Navigation Satellite System (GNSS) and is taken as an important target of interference monitoring. However, there are hardly any researches on signal separation and parameter...
Time synchronization has received a great attention as its crucial parts in wireless sensor networks. To minimize the number of transmission packets and achieve energy efficiency, a time synchronization scheme based on ant colony algorithm (TSAC) is presented in this paper. By exploiting the principle of ant colony algorithm adjusting the pheromone dynamically and automatically, an optimum pair selection...
This paper mainly introduces some related problems about special mobile communication signal based on TD-LTE and TD-SCDMA in high-speed railway, summaries the main difficulty of TD-LTE coverage in high-speed railway and analyses TD & LTE wireless network coverage characteristics and key technologies under the environment of high-speed railway. First, we make a contrast of the coverage range of...
In Machine-to-Machine (M2M) communication networks, the signalling congest and complexity for resource allocation is becoming one of the most important problems that should be dealt with the increasing of network scale. In this context, a clustering transmission strategy for the large-scale M2M networks has been proposed in this paper. To make the scheme can be carried out in distributed way, a joint...
With the development and evolution of the LTE system, the operators are experiencing huge challenges on operations and service maintenance, which sets off a wave of SON (Self-organizing Network) research. As one of the crucial component of SON, the cell outage detection is an effective way to automatically detect outage cells resulted from hardware or software problems. Our work in this paper aims...
In cognitive radio networks, the improved energy detector is a very useful detector for the random signals corrupted by Gauss noise. In the single node sensing, we research the change of p values which has impacted on system performance under certain signal to noise ratio and obtain the optimal p values making the Bayes risk minimum. In the cooperative spectrum sensing, we use “K-out-of-N” rule and...
In the power line communication system(PLC), due to the commercial PLC modems feature low power transmission and the large amount of noise, the communication system has a very low signal to noise ratio(SNR) which seriously affects the reliability of the signal transmission. Considering the situation of low SNR, this paper presents a noise mitigation method based on normalization time-frequency peak...
In order to solve the balance problems between efficiency and accuracy encountered in content-based video retrieval, in this paper, we propose firstly a video retrieval scheme based on coarse granularity. To achieve the coarse-grained video retrieval, we use inverted index. Further, we expose an improved BLAST algorithm to realize fine-grained retrieval of video fingerprint. Finally, simulation results...
An online charging signaling procedure in packet switching system is analysed. Appropriate parameters can be selected in order to reduce the number of account operation and amount of signaling by omitting some credit reauthorization process. An online charging model is proposed by using the signaling procedure optimization. In the model, session based charging function is divided into six closely...
While distract interference alignment needs ideal channel state information (CSI), it is difficult to achieve in real communication system. But reality communication system possesses feedback link. Based on this, interference alignment (IA) with limited feedback was proposed. Channel coefficient matrices is quantified at receivers, and then the precoding matrix will be designed with the quantified...
In this paper, an SLNR based cascaded interference align precoding algorithm is proposed according to the study on interference suppression in downlink coordinated multipoint transmission system. In this algorithm, cascaded precoding is adopted rather than delivering channel state information (CSI) among cells to deal with inter and inner cell interference stage by stage. In the first stage, interferences...
A new frequency estimator of sinusoid based on interpolated FFT amplitudes is proposed. Firstly, zeros of length N are padded to the sinusoid sampled data of length N in the time domain. Next, 2N-point FFT is performed and the coarse estimation is made by searching the location of the spectrum line with maximum amplitude. Finally, the fine estimation is made by utilizing the amplitudes of the spectrum...
Space shift keying (SSK) modulation is a newly emerging transmission technology for multiple-input multiple-output (MIMO) wireless systems. In this paper, we propose a novel high rate transmit diversity assisted space shift keying (HT-SSK) modulation scheme to achieve the transmit diversity gain over SSK system with high spectrum efficiency. We first apply antenna shift method at each time slot to...
The vehicular ad-hoc network (VANET) is a promising technology in near future. VANET allows vehicles to communicate with each other and with roadside units (RSUs). Wireless Access in Vehicular Environment (WAVE), defined by IEEE, provides the Internet connectivity for vehicles as well as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication. RSUs can form a wireless mesh network...
RPL is an IPv6 routing protocol arming at low power consumption lossy networks, which is very important to the development of wireless personal area network. By studying the discovery mechanism of RPL routing protocol in wireless sensor networks, we found that advantage routing nodes may die prematurely due to excessive use in current RPL mechanisms, which can cause the entire network life cycle greatly...
For the most existing MAODV protocol is only improved by a single performance, there is a problem that the comprehensive performance of the protocol cannot be improved as well. By uses of the routing selection mechanism with the constraints of bandwidth, delay and packet loss rate of the original protocol, a new multi-objective routing protocol RCQ-MAODV of mobile ad hoc network is put forward. Simulations...
We study invulnerability of complex networks subject to attacks on nodes and links. For the purpose of precisely assessing invulnerability of complex networks, in this paper we proposed an invulnerability assessment on the basis of importance-degree and partial attack information by measuring two metrics of network invulnerability, robustness and efficiency. We defined the term of importance-degree...
Existing virtual network mapping algorithms does not consider resource consumption of intermediate node on communication path usually. Minimum resource consumption or shortest path of physical network is regarded as objective, thereby leading to bottleneck due to insufficient resource of intermediate node on communication path, and affecting performance of the whole physical network and subsequent...
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