One of the fundamental limitations of mobile radio communications is their timevarying fading channel. This thesis addresses the efficient use of channel state information to improve the communication systems, with a particular emphasis on practical issues such as compatibility with the existing wireless systems and low complexity implementation. The closed-loop transmit diversity technique is ...

In previous literature on adaptive transmission in multiuser OFDMA systems, only uncoded case or capacity (coded with infinite length of codeword) has been considered. In this paper, an adaptive transmission algorithm for coded OFDMA systems with practical codeword lengths is investigated. Also, in order to keep the feedback overhead within a practical range, a two-step partial CQI scheme is ad...

The effect of different spreading codes in DWT based MC-CDMA wireless communication system is investigated. In this paper, we present the Bit Error Rate (BER) performance of different spreading codes (Walsh-Hadamard code, Orthogonal gold code and Golay complementary sequences) using Forward Error Correction (FEC) of the proposed system. The data is analyzed and is compared among different sprea...

We consider the problem of sending two correlated random sources over a Gaussian multiple-access channel. The sources are assumed to be temporally memoryless. The performance criterion is the MSE and we seek linear transceivers that minimize it. When the bandwidth expansion factor is unity, it is shown that uncoded transmission is the best linear code for any SNR. When the bandwidth expansion f...

This paper studies the adaptive coded modulation for OFDM system using punctured convolutional code, channel estimation, equalization and SNR estimation. The estimation based on block type pilot arrangement is performed by sending pilots at every sub carrier this a specific number of following symbols. Signal to noise ratio estimated receiver then transmitted transmitter through feedback ,the a...

This paper reports on field measurements of point-to-point indoor high-speed (10 Mbit/s to 30 Mbit/s at 5 Mbaud) wireless communications realized using a flexible multilevel quadrature amplitude modulation (M-QAM) testbed that features real-time equalization and smart antenna-array technology. The results from an extensive set of measurements, 59 262 trials in all, performed without cochannel i...

The closed-loop transmit diversity technique is used to improve the performance of the downlink channel in MIMO communication systems. The WCDMA standard endorsed by 3GPP adopts two modes of downlink closed-loop schemes based on partial channel state information. The information is fed back from the mobile unit to the base station through a low-rate uncoded feedback bit stream. Previously [1], ...