نتایج جستجو برای: multipath fading channel
تعداد نتایج: 240253 فیلتر نتایج به سال:
Wireless communication demands high data rates with great quality and accuracy but such requirements can only be achieved if the signal could be received without being affected by the channel impairments. In these entire impairments multipath fading is the major problem in achieving reliable wireless transmission. It is due to the combination of constructive and destructive multipath signals re...
CDMA systems in multipath fading channels need to estimate channel parameters for coherent detection of the transmitted signals. In this paper we present a simple but effective channel estimation algorithm that can be incorporated into most types of multiuser receivers to obtain good detection performance. This technique uses a set of correlation filters to independently estimate each of the ch...
In this paper we discuss the proper normalization of a fading channel model. Physically, radio channels correspond to passive circuits and follow the energy conservation law. The ratio of the received energy to the transmitted energy is the energy gain of the channel. The representative energy gain is defined as the average energy gain for a signal that is uniformly distributed in time, frequen...
The mobile wireless channel o ers inherent diversity by virtue of multipath and Doppler shifts. Multipath diversity is exploited via spread-spectrum signaling employed in code division multiple access (CDMA) systems. However, the RAKE receiver commonly used in CDMA systems exploits only multipath diversity, and consequently su ers from signi cant performance degradation under fast fading. We de...
We study the performance of a UMTS downlink, as achieved by a single-user (RAKE) and a multiuser (linear MMSE) receiver with adaptive modulation and multicode in the presence of multipath fading. We advocate an adaptive transmission scheme that varies the number of virtual users and the modulation spectral efficiency in order to optimize the system throughput. Two multipath channel models are c...
Blind adaptive equalization with application for Non-Linearly Amplified (NLA) quadrature amplitude modulation (QAM) systems in multipath selective fading channels is presented. With an offset sampling strategy in the receiver, the proposed blind equalization using Constant Modulus Algorithm (CMA) exhibits a fast convergent speed for a family of quadrature modulated systems in NLA and multipath ...
This project studies and identifies the PSK-based digital modulation scheme (BPSK, QPSK or GMSK) that gives the best BER performance in a multipath fading environment using computer simulation (MATLAB). Each PSK-based digital modulation are modeled and simulated under different channel conditions. Subsequently, a comparison study is carried out to obtain the BER performance for each PSK-based t...
It is of great interest to provide high data rate services in wireless communication systems. In order to support such services, it is desirable to extend space-time (ST) coding, originally proposed for known, frequency-nonselective fading channels, to unknown, multipath channels. In this paper, we consider the problem of interference suppression for wireless TDMA (time division multiple access...
One of the major challenges in wireless communication system is increasing complexity and reducing performance in detecting the received digital information in indoor and outdoor Environments. Consequently to overcome this problem we analyze the delay performance of a multiuser with perfect channel state information transmitting data on deep fading environment. In this proposed system, the Wire...
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