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We attempt to analytically formulate the spectral efficiency and outage probability of multihop cellular systems, in which mobile stations and base stations can communicate by using multihop relaying. This multihop relaying has the same ability as symbol rate control to enhance the end-to-end communication range at the loss of spectral efficiency. According to this commonality, a similar methodology...
In this paper, a multistage parallel interference canceller (MPIC) with multi-beam reception for a DS-CDMA system was proposed to suppress multiple access interference (MAI) effectively. Its aim is to reduce the computational complexity of the conventional MPIC cascaded with an adaptive array antenna. It employs multiple fixed beams based on phased array and selects suitable beams to demodulate the...
All communications in a network made by mobile hosts through a shared radio link without cable or backbone, commonly called mobile ad hoc network (MANET). Since the network topology may change constantly because of mobility of nodes and the available routes may fail many times, quality-of-service (QoS) of real-time multimedia application may have difficulty in satisfying their services. In this paper,...
Ad hoc network is a set of mobile nodes that each mobile host is able to move freely and the network is unpredictable topologies transformation. Therefore, the searching for transmission path becomes difficult and complicated. Because each mobile host in ad hoc network acts as a switching node that routes and forward packets to its neighboring mobile hosts (or nodes), hop by hop, or multi-hop. Unlike...
Quality of service (QoS) provisioning in a mobile ad hoc network (MANET) is expected to become important because of the diversity of applications that these networks will have to carry. However it tends to be difficult due to constraints of MANETs such as the changing network topology, shared and variable wireless bandwidth and limited power supply. In this paper, a cross-layer scheduling approach...
This paper proposes a two-stage featureless hierarchical algorithm to alleviate the problems encountered in the VideoOrbits (and other related) algorithms for estimation of the projective coordinate transformation between images. Translation, rotation and zoom parameters are estimated by phase correlation methods in the first stage, which are used as initial estimates of Orbits in the second stage...
A high efficiency and contrast enhanced halftoning is presented in this paper. The contrast of digital image highly depends on the nature of the ambient lighting and the quality of the lens. The required processing time skyrockets when a high resolution and quality printed work is needed. In this paper, we employ the benefits of high speed ordered dithering and high quality error diffusion to simultaneously...
An efficient video de-interlacing technique with scene change detection is proposed and its performances are examined. Scene changes happen quite often in film broadcasting and they tend to destabilize the quality of performance such as jagged effect, blurred effect, and artifacts effect, while de-interlacing technique is utilized. Therefore, the issue of scene change needs to be addressed with de-interlacing...
Human motion detection is a fundamental part for many computer vision tasks and various methods have been proposed. Background subtraction is a very popular method where the classification of pixels into motion pixels and background pixels is based on thresholding the difference image between a background image and a current image. The choice of threshold is crucial and many methods have been employed,...
TCFA problem is a traditionally hard problem in the optimization of toll telecommunication network. Practically we utilize simulated annealing (SA) algorithm to indirectly solve a simplified version of TCFA problem. In this paper, particle swarm optimization (PSO) and extended particle swarm optimizer (EPSO) are introduced briefly associated with some other significant alterations. Simulation based...
The data link antenna system must be always pointed to a moving target for communication. Especially, for an antenna mounted on a moving vehicle, it needs the stabilized the antenna system. So, software and hardware, signal processing of motion detection sensors, real-time processing of vehicle dynamics, trajectory estimation of satellite, antenna servo mechanism, and tracking algorithm are unified...
This paper presents a CMOS circuit technique for realization of the current-mode multiple-input max/min circuit. The maximum and minimum functions are incorporated into the same scheme with parallel processing. The design strategy is based on the use of MOS transistor operating at the edge of conduction. The proposed circuit performs a low-distortion in the transfer characteristic and is useful building...
Coupled with a robust and efficient OFDM air interface, MIMO technologies lead to a very compelling high speed data link solution for future wireless multimedia systems. This article presents MIMO-OFDM concept prototype of signal processing operations and simulate performance results. The prototype is based on the IEEE 802.11a/g standards at physical layer, supporting multiple antennas, adaptive modulation...
This paper presents a new analysis and synthesis filters design method for achieving nearly perfect reconstruction low group delay cosine-modulated filter bank (CMFB). The objective is to show how far we can reduce the overall group delay of this proposed CMFB by using this new analysis and synthesis filter prototypes. Simulation results show that the overall group delay of our proposed approach can...
A generalized fractional process is a fairly general model of long-memory, applicable in modeling many random signals whose autocorrelations exhibit hyperbolic and periodic decay. In this paper, we derive a wavelet-based weighted least squares estimator of the long-memory parameter that is relatively efficient. Results show that the proposed method is relatively computationally and statistically efficient...
We introduce two new perfect reconstruction (P.R.) decompositions for signals on a hexagon lattice. One is an orthogonal compaction (coding) transform similar to that used in the Simoncelli-Adelson quadtree pyramid, but with perfect reconstruction and compact integer-valued filters. The other is a 3-ary "blurring" filter bank which has a perfect inverse ("sharpening") filter bank...
To perform variable fractional-delay (VFD) filtering, the VFD parameter p is assumed to take fractional numbers in pisin[0,1] and pisin[-0.5, 0.5] in the literature, but it needs to be clarified that which range should be adopted for achieving high-accuracy VFD filtering. In this paper, we first analyze the accurate range qualitatively, and then utilize interpolation examples to demonstrate that range...
This paper is devoted to the precise performance analysis of optimum diversity combining and equalization with quadrature amplitude modulation (QAM) over frequency-selective fading channels in the presence of co-channel interference (CCI). In developing the optimum receiver, a precise CCI model with taking into account the effects of symbol and carrier timing offsets between the desired signal and...
This paper discusses WCDMA mobile terminal receivers that employ dual antenna LMMSE equalization in high speed downlink packet access (HSDPA) multicode transmission. The strong correlated inter-cell interference is a major concern for a mobile terminal in realistic cellular environments. In this paper the channel characteristics of the serving and interfering base stations are taken into account using...
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