The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A novel beam-forming detector for group space-time coded systems is proposed in this paper, which utilizes unitary preprocessing in the transmitter to simplify the decoding complexity in the receiver. Eigenmode selection is introduced to achieve more system diversity gain. Furthermore, a simple example for variable-rate group space-time coded systems is presented. Simulation results show that the...
OFDM/CPM is now a recognized alternative to conventional OFDM for the transmission of signals over nonlinear channel. This paper presents a characterization of nonlinear distortion effects in orthogonal frequency-division multiplexing/continuous phase modulation (OFDM/CPM) transmission systems. In a second step, a comparison with simulation results is carried out to show that CM is more suitable to...
In this paper, we first analyze the amount of fading (AF) of orthogonal space-time block codes (STBCs) over spatially uncorrelated keyhole channels. In order to investigate the diversity order of keyhole channels, we then derive an approximate expression for the average bit error rate (BER) at high signal-to-noise ratio (SNR). Finally we present the average capacity expression by applying the Gauss-Laguerre...
In this paper, we present numerical results to show the performance of power control (PC) by using antenna arrays at the base station (BS). We show that the diversity generated by antenna array, decreases the outage probability, the bit error rate (BER), the fluctuations of the received signal to interference ratio (SIR) over the target SIR, the transmitted power level, and finally increases the speed...
This paper proposes a new approach to the closed-loop power control algorithm with decision feedback, called NAPC-DF algorithm. In this algorithm, the step size of the transmitting power by the mobile station (MS) in uplink channel is variable and adjusted by the received command from the base station (BS) and channel conditions. This algorithm is compared with fixed-step, variable step and adaptive...
A Grouping method of bit and power allocation in orthogonal frequency division multiplex (OFDM) system is presented in this paper. The complexity of BABGS algorithm, as bit allocation based on grouping subcarriers (BABGS), is lower than suboptimal algorithms. This algorithm aims to minimize the total transmitted power under the constraint of bit error rate (BER) and total bit rate, so it is based...
Based on the characteristics of Bridge function, i.e. zero and nonzero distribution, bridge function's spreading spectrum feature was analyzed and concluded that it is a kind of discrete spreading mode. In specific channel environment, if coherent bandwidth and single sub-carrier bandwidth is known, we can choose the shift parameters for bridge function sequence to get the best frequency diversity...
The maximum likelihood (ML) approach is a classical approach to the channel estimation problem. However, without reducing the number of parameters, the complexity is prohibitive. This paper proposes a (data-aided) DA simplified ML channel estimation algorithm based on unstructured channel model and time-hopping binary phase shift keying (TH-BPSK) modulation for impulse radio (IR) UWB systems. This...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.