Current Issue : October - December Volume : 2013 Issue Number : 4 Articles : 6 Articles
This paper addresses distributed parameter coordination methods for wireless communication systems. This proposes\r\na method based on a message-passing algorithm, namely min-sum algorithm, on factor graphs for the application of\r\nprecoder selection. Two particular examples of precoder selection are considered: transmit antenna selection and\r\nbeam selection. Evaluations on the potential of such an approach in a wireless communication network are provided,\r\nand its performance and convergence properties are compared with those of a baseline selfish/greedy approach.\r\nSimulation results for the precoder selection examples are presented and discussed, which show that the\r\ngraph-based technique generally obtains gain in sum rate over the greedy approach at the cost of a larger message\r\nsize. Besides, the proposed method usually reaches the global optima in an efficient manner. Methods of improving\r\nthe rate of convergence of the graph-based distributed coordination technique and reducing its associated message\r\nsize are therefore important topics for wireless communication networks....
In this paper a novel architecture of ASIP for a reconfigurable FFT is proposed. The proposed design implements a ASIP for reconfigurable 64 point FFT processor with a high speed. Hence design of reconfigurable FFT processor is proposed which can be used for various ASIPs.ASIPs are widely 3G cellular systems,wireless communication,OFDMA,ECG. The method optimizes the processing, by wiping out the non-trivial complex multiplication with the twiddle factors and fulfills the processing with no complex multiplication. is defined constant fixed for every Butterfly stage which act as Twiddle factor multiplier. To reduce the complexity of the multiplication, proposed method can be used which replaces the expensive complex multiplications with real and constant multiplications. Proposed design implements DIF-FFT algorithm using VHDL language and Xilinx 9.1i for simulation results....
This paper presents the capacity analysis of a threshold-based SNR scheduler in the long-term evolution (LTE)\r\ncellular systems. LTE standard has adopted multiuser OFDMA, and stipulates adjacent subcarrier groupings for\r\nmapping the physical OFDM subcarriers into resource blocks that form the basic unit of radio resource\r\nmanagement (RRM) in LTE network. The standard however did not specify the details of the RRM algorithm to be\r\nemployed, leaving this aspect for vendors to differentiate their products. Popular RRM algorithms such as roundrobin\r\n(RR), proportional fairness (PF), and maximum SNR (MaxSNR), have been implemented recently as operatorselectable\r\noptions on LTE base station (BS). In this paper, we present a threshold-based SNR scheduler that has the\r\ncapability of modeling all of the above-mentioned algorithms and thus allows vendors to combine the separate\r\nimplementations of these algorithms into one generalized scheduling algorithm, where the threshold level used at\r\nany time instant defines the scheduling discipline to be realized. We derive the capacity enhancement achievable\r\nusing the proposed scheduling scheme, and also present system-level simulations to corroborate the analysis. Our\r\nanalytical and simulation results indicate that the proposed algorithm models the existing ones closely at different\r\nvalues of the threshold. The results also demonstrate the data rate enhancements, and the level of user fairness,\r\nachievable in the network for various levels of the threshold...
Three-dimensional wavelet transform (3D-DWT) encoders are good candidates for applications like professional video\r\nediting, video surveillance, multi-spectral satellite imaging, etc. where a frame must be reconstructed as quickly as\r\npossible. In this paper, we present a new 3D-DWT video encoder based on a fast run-length coding engine.\r\nFurthermore, we present several multicore optimizations to speed-up the 3D-DWT computation. An exhaustive\r\nevaluation of the proposed encoder (3D-GOP-RL) has been performed, and we have compared the evaluation results\r\nwith other video encoders in terms of rate/distortion (R/D), coding/decoding delay, and memory consumption.\r\nResults show that the proposed encoder obtains good R/D results for high-resolution video sequences with nearly\r\nin-place computation using only the memory needed to store a group of pictures. After applying the multicore\r\noptimization strategies over the 3D DWT, the proposed encoder is able to compress a full high-definition video\r\nsequence in real-time....
A novel scheme to achieve three-dimensional (3D) target location in bistatic radar systems is evaluated. The\r\nproposed scheme develops the additional information of the bistatic radar, that is the transmit angles, to estimate\r\nthe 3D coordinates of the targets by using multiple-input multiple-output techniques with a uniform circular array\r\non transmit and a uniform linear array on receive. The transmit azimuth, transmit elevation angles and receive cone\r\nangle of the targets are first extracted from the receive data and the 3D coordinates are then calculated on the\r\nbasis of these angles. The geometric dilution of precision which is based on the root Cramer-Rao bound of the\r\nangles, is derived to evaluate the performance bound of the proposed scheme. Further, an ESPRIT based algorithm\r\nis developed to estimate the 3D coordinates of the targets. The advantages of this scheme are that the hardware of\r\nthe receive array is reduced and the 3D coordinates of the targets can be estimated in the absence of the range\r\ninformation in bistatic radar. Simulations and analysis show that the proposed scheme has potential to achieve\r\ngood performance with low-frequency radar....
In this paper, we formulate relay selection into a Chinese restaurant game. A secure relay selection strategy is\r\nproposed for a wireless network, where multiple source nodes send messages to their destination nodes via several\r\nrelay nodes, which have different processing and transmission capabilities as well as security properties. The relay\r\nselection utilizes a learning-based algorithm for the source nodes to reach their best responses in the Chinese\r\nrestaurant game. In particular, the relay selection takes into account the negative externality of relay sharing among\r\nthe source nodes, which learn the capabilities and security properties of relay nodes according to the current\r\nsignals and the signal history. Simulation results show that this strategy improves the user utility and the overall\r\nsecurity performance in wireless networks. In addition, the relay strategy is robust against the signal errors and\r\ndeviations of some user from the desired actions....
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