This paper addresses joint channel and data estimation for transmission over frequency-selective and timevarying channels based on a Doppler-variant channel impulse response (CIR). A discrete spreading function (DSF), which corresponds to the Doppler Fourier series of the time-varying channel taps, is introduced. The spectral leakage associated with the Fourier series representation is reduced ...

This paper investigates channel pre-equalization for the up-link of multi-carrier code division multiple access (MC-CDMA) mobile cellular systems. This technique solves the crucial problem of up-link channel estimation by keeping the high spectral efficiency of MC-CDMA with no need of pilot symbols. We study an optimisation criterion based on the maximization of the signal over interference plu...

In the next generation mobile communication systems, multiple-input multiple-output (MIMO) multiplexing is an indispensable technique to achieve very high-speed data transmission with a limited bandwidth. In MIMO multiplexing, it is necessary to estimate the channels between transmit and receive antennas for signal detection. In this paper, we propose a minimum mean square error (MMSE) channel ...

We propose a subspace based blind channel estimation method for OFDM systems over a time-dispersive channel. Our approach is motivated by the resemblance of the multichannel signal model resulting from oversampling (or use of multiple receive sensors) of the received OFDM signal to that in con-. ventional single carrier system 113. The proposed algorithm distinguishes itself from many previousl...

Time division duplex multi-carrier code-division multiple-access (TDD/MC-CDMA) operates on the premise that there is a strong correlation between upand downlink channel conditions. When using TDD mode, the effects of the channel on the uplink signal can be pre-compensated at the mobile station, based on the channel estimation from the downlink frame. The aim of this paper is to carry out a perf...

Telecommunications in the current information age is increasingly relying on the wireless link. This is because wireless communication has made possible a variety of services ranging from voice to data and now to multimedia. Consequently, demand for new wireless capacity is growing rapidly at a very alarming rate. In a bid to cope with challenges of increasing demand for higher data rate, bette...

Beyond third generation (3G) and fourth generation (4G) wireless communication systems are targeting far higher data rates, spectral efficiency and mobility requirements than existing 3G networks. By using multiple antennas at the transmitter and the receiver, multipleinput multiple-output (MIMO) technology allows improving both the spectral efficiency (bits/s/Hz), the coverage, and link reliab...

The distributed nature of cooperative networks may result in multiple carrier frequency offsets (MCFOs) and multiple timing offsets (MTOs), which overshadow the diversity gains promised by cooperative communications. So the estimation of MCFOs and MTOs is an important implementation issue in practice. In this paper we propose a new channel estimation both at the relays and the destination in di...

Problem statement: Maximum Likelihood (ML) decoding has been applied for the uplink of a Multi-Carrier Code Division Multiple Access (MC-CDMA) system based on Orthogonal Frequency Division Multiplexing (OFDM). Multiple-Input Multiple-Output (MIMO) channel from k users, which moves at vehicular speed, to the Base-Station (BS) is time-varying. For time-varying channels, Sphere Decoding (SD) was i...

Multi-Carrier Code Division Multiple Access (MC-CDMA) is a modulation scheme that combines the advantages of OFDM and CDMA to provide robustness against frequency selectivity in wireless channels. Arrayed MC-CDMA systems combine MC-CDMA and antenna array technology to harness the spatial and temporal ’signatures’ of received signals, thus making it possible to realize high transmission rates en...