Transmitter diversity at the base station of a cellular mobile radio system provides a means to achieve performance gains similar to those obtained with mobilestation receiver diversity, but without the complexity of a mobile-station receiver antenna array. We investigate Selective Transmit Diversity (STD) in the downlink of the Wideband Code Division Multiple Access (WCDMA) mobile radio channe...

This paper deals with the simulation of Nakagami fading in wireless channels using Orthogonal Frequency Division Multiplexing (OFDM) technique using Differential Quadrature Phase Shift Keying (DQPSK) modulation scheme. The paper proposes approximate methods for deriving Bit Error Rate (BER) in DQPSK-OFDM systems over frequency-selective Nakagami fading channels. The numerical results are plotte...

We investigate the effects of fading correlations on wireless communication systems employing multiple antennas at both the receiver and the transmitter side of the link, so called multiple-input multiple-output (MIMO) systems. It turns out that the amount of transmitter sided channel knowledge plays an important part when dealing with fading correlations. Furthermore, the possible availability...

| MultiCarrier CDMA (MC-CDMA) schemes resolve the frequency selectivity in multipath fading channels and have good spectral properties. Spreading the information over many subcarriers adds exibility to the system and a redundancy between subcarriers that can be combined nicely with the derived frequency diversity out from the fading channel. In this paper the performance of a MC-CDMA scheme ove...

The estimation of the scattering function in time-frequency selective fading mobile environment is considered. The scattering function explicitly reveals the time-frequency selective behavior of the fading channel under the well-known WSSUS assumption. We propose two classes of estimators based on a time-frequency framework that generalize the existing estimators while giving an extra freedom a...

A b s t r a c t T h i s paper presents a method of sequence estimation using joint data and channel estimation for the frequency selective Rayleigh fading channel. To detect the transmitted data sequence, a generalized Viterbi algorithm is employed in which each trellis branch metric is computed based on an estimation of the channel impulse response. The information from the survivor path estim...

Time-frequency-selective, i.e., time-variant multipath, fading in orthogonal frequency division multiplexing (OFDM) systems destroys subcarrier orthogonality, resulting in intercarrier interference (ICI). In general, the previously proposed estimation schemes to resolve this problem are only applicable to slowly time-variant channels or suffer from high complexity due to large-sized matrix inve...

This paper considers a resource allocation problem in the downlink of a multiuser, multicell OFDM cellular network with frequency selective fading and imperfect channel state information. Each user has a given data rate requirement. The task is to determine power and subcarrier allocations for users to ensure that users’ outage probabilities are low. A two-layer approach is used. The higher lay...

Linear adaptive equalizers are widely used in wireless communication systems in order to reduce the effects of the channel distortion. Various researchers have used linear block equalizers for different modulations techniques. In this paper the BER performance of different M-PSK and M-QAM modulations with the block based LMS and RLS linear equalizers are compared over the flat and frequency sel...

We consider a space–time coded (STC) orthogonal frequency-division multiplexing (OFDM) system with multiple transmitter and receiver antennas over correlated frequencyand time-selective fading channels. It is shown that the product of the time-selectivity order and the frequency-selectivity order is a key parameter to characterize the outage capacity of the correlated fading channel. It is also...