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In this paper, we propose a new method of secrecy signal and artificial noise (AN) transmission for a MISO wiretap channel in wireless cellular networks. We first design the secrecy signal beamformer such that its power leakage to the unintended directions is minimized, then we concentrate the AN on the directions with higher risk of information leakage, rather than broadcast it isotropically, such...
In this paper, a low overhead preamble structure is proposed for the interference approximation method — complex (IAM-C) method in offset quadrature amplitude modulation based orthogonal frequency division multiplexing (OQAM-OFDM) systems. Compared with the conventional preamble structure with three columns of symbols, the proposed preamble structure only requires two columns of symbols as the preamble...
Recently there has been renewed interest in the application of photoplethysmography signals for cardiovascular disease assessment. Photoplethysmography signals are acquired non-invasively using visible and infrared light passed through the finger pulp. Unfortunately, this method commonly suffers from many forms of interference and distortion such as; baseline wander, mains-line interference and random...
In this work, we propose a novel algorithm to combat the clipping noise in Interleave-division multiple access (IDMA) which inherits a peak-to-average power ratio (PAPR) problem especially in large number of multiple accesses. Clipping transmission is efficiently applied to reduce the PAPR to cause the clipping noise which is a weak tradeoff [1][2] to its performance. The proposed algorithm consists...
In this paper, a turbo-coded optical interleave-division multiple-access (OIDMA) scheme is studied. A maximum a posteriori (MAP) based asynchronous on-off keying (OOK) MUD algorithm is proposed. Besides, system capacity is analyzed with an iterative technique called SNR evolution. BER is evaluated over log-normal turbulence channels, taking into consideration the effects of thermal noise and background...
In order to solve the object parameter identification problems which exist in the high precision intelligent control system, the paper presents object parameters identification method using accumulative sum based on the traditional parameter identification ones. It gives the calculate formulae and judgment condition and threshold range according to computer simulation experiment. The experiment results...
The wireless ad-hoc networks do not rely on any infrastructure, which comes at the cost of finite and usually unreplenishable power supplies. It has been an area of intense research how to perform effectively maximum lifetime multicast delivery. This paper presents a new method for this problem, called the Directional Reception Two-step Reconstruction (DRTR). Firstly, based on conventional ad-hoc...
This work introduces a new robust high resolution algorithm for space spectrum based on the direct data domain least square (D3LS) method. This work adds a virtual desired signal to the receiving data and treats the actual desired sources as interferences. Then nulls result on the direct of the actual desired sources by D3LS adaptive processing. A new beampattern is got after proper processing of...
A kind of signal space characteristic estimate method is proposed in this article based on higher order cumulants, which is suitable for parameter estimation of interference signal under multi-path propagation environment. By uniform linear array and its improving, we developed an analysis model of receiver that mixed signal and interference. In order to research time-frequency distribution at different...
The performance of set-membership normalized least mean-square (SM-NLMS) adaptive filters deteriorates significantly in the presence of impulsive noise or interference. To solve this problem a new robust SM-NLMS (RSM-NLMS) algorithm is proposed. In addition, a framework to achieve robust performance in other algorithms of the set-membership (SM) family is developed. The proposed RSM-NLMS algorithm...
Vehicular ad hoc networks (VANETs) are an important example of mobile ad hoc networks (MANETs) because they can save lives by improving safety on our road networks. They are difficult to design however due their inherent characteristics e.g., quickly changing topology, node density and relative speeds of vehicles. These characteristics also make current wireless media access control (MAC) protocols...
The uplink total interference and the ratio of interference from inter-cell to from intra-cell of TD-SCDMA base station is analyzed in this paper by the method of simulation. The results of uplink ratio of interference from other cells to from own cell and noise rise of base station are given with smart and directional antenna respectively. Some suggestions are also provided for TD-SCDMA network planning.
In this paper, the coexistence issue between macro/micro WCDMA system and macro WiMax system has been investigated. Monte Carlo simulation method is used to evaluate the impact of inter-system interference produced by coexistence of systems in the same geographical area in adjacent frequency. Based on the analysis of the interference, we come to the conclusion whether WCDMA and WiMax systems could...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
Spectrum sensing in the context of wireless microphone (WM) signals is considered in this paper. The spectrum sensing algorithm developed in this study makes use of the property that the bandwidth of the WM signal is narrow compared with the bandwidth of a digital television (DTV) channel. As a result, the power of the WM signal is highly concentrated in the frequency domain and there are apparent...
Opportunistic routing (OR) schemes, such as ExOR, have been shown to provide significant throughput gains over traditional best-path routing schemes for wireless networks. Though the performance of OR schemes depend on the bit-rate, they currently use a fixed rate for transmitting packets. While several schemes have been proposed for selecting bit-rate for unicast transmission to a single receiver,...
We propose a novel distributed cross-layer optimization approach for cognitive radio wireless networks. A cognitive radio is a wireless device that is capable of sensing the prevailing environmental conditions and automatically adapting its operating parameters in order to enhance the performance of both the system and potentially the whole network. Given the lack of a centralized intelligence to...
Advances in micromachining technology can facilitate the integration of SAW (Surface Acoustic Wave) devices and CMOS circuitry on IC scale substrate for Monolithic fabrication. The optimal design and performance of these filters can be reached by using new Smart materials. The key component in the structure of the SAW device is the piezoelectric materials used which depends mainly on some important...
The paper presented a new technology of industrial field concurrent bus communication. Based on direct sequence spread spectrum, frequency division multiaddress and cross correlation as necessary auxiliary method,it realized a new concurrent field bus communication. The purpose of this study was to overcome common fault existed in communication mode of industrial control field such as 485/232 or CAN...
Underwater acoustic channel (UACh) requires robust techniques to get high speed data transmission for reliable communication. This paper presents the adaptive transmission technique in conjunction with the maximal ratio combining (MRC) diversity technique to adapt the UACh fluctuation based on a statistical channel model. Simulation analysis shows that we can optimize the data rate allowing the transmit...
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