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.
This paper addresses the optimization of resource allocation based on Decode and Forward (DF) or Amplify and Forward (AF) relaying techniques for packet access Orthogonal Frequency Division Multiple Access (OFDMA) networks. A power allocation quasi-optimal solution with a low complexity has been proposed for the two forwarding techniques. To illustrate theirs performances, a selection of numerical...
For multiple-input multiple-output (MIMO) wireless communication system with minimum mean square error (MMSE) detection, power allocation between pilot and data symbols is investigated under MMSE channel estimation in this paper. We first propose a novel soft-output MMSE MIMO detector by taking the channel estimation error into consideration. Then, by random matrix theorem, we propose an effective...
In this paper, we propose a double space-time transmit diversity (DSTTD)-based two-path relay system with power allocation and link combining methods. The two-path relaying protocol can restore spectral efficiency decreased due to the half-duplexing at the relay nodes and the DSTTD method can appropriately achieve the diversity gain from the two paths. To circumvent severe performance degradation...
We propose a cross-layer strategy that jointly optimizes user scheduling and resource allocation for adaptive modulation and coding (AMC) based orthogonal frequency multiple access (OFDMA). The objective of this paper is to maximize the system throughput as a function of the bit error rate (BER) and the spectral efficiency based on selected modulation and coding schemes (MCSs). The proposed optimal...
A dynamic symbol mapping technique is proposed for downlink and point-to-point multiple input multiple output (MIMO) systems. The proposed mapping introduces a perturbation to the transmitted symbols by adaptively changing the order or the values of the symbols to be transmitted within a sub-frame of symbols with the objective to enhance the received symbols' power. The symbol mapping aims at taking...
In a downlink transmission, users can benefit from the high capacity gain achieved by transmitting independent data streams from multiple antennas to multiple users sharing the same physical time-frequency resources. This technique is known as multiuser MIMO (MU-MIMO). However, performance of MU-MIMO is sensitive towards propagation imperfections, such as time dispersion and inter-stream interference...
Adaptive modulation and power allocation schemes have been widely used in multiple-input multiple-output (MIMO) systems to enhance spectral efficiency while maintaining bit error ratio (BER) to a target level. We derive the spectral efficiency of orthogonal space-time block codes (OSTBC) that can be achieved by applying adaptive modulation and power allocation. Compared to non-adaptive power scheme,...
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.