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.
The successful deployment of LTE heterogeneous networks (HetNets) depends crucially on the inter-cell interference (ICI) management. Among ICI coordination schemes, fractional frequency reuse (FFR) is considered as an efficient technique well-suited to OFDMA-based HetNets. Two coupled questions in this context are: 1) how to associate users to appropriate basestations considering the long list of...
This paper provides a joint implementation of Fractional Frequency Reuse (FFR) and relays in the downlink of multi-cellular networks like Long Term Evolution (LTE) networks. The forecasted benefits concern inter-cell interference (ICI) mitigation in each cell. Based on this network architecture and related improvements, individual user throughputs and signal to interference plus noise ratio (SINR)...
We investigate the joint implementation of back-propagation and RF-pilot tone for fiber nonlinear compensation in POLMUX-16QAM and show that the nonlinear tolerance is drastically improved when compared to OFDM system.
A joint synchronization and channel estimation algorithm based on Recursive Least Squares (RLS) is proposed for frequency hopping orthogonal frequency division multiplexing (FH-OFDM) systems in aviation mobile communications above sea. Complex computation is avoided by mitigating Inter-Carrier Interference (ICI) in time domain, which is induced by Carrier Frequency Offset (CFO) and Sampling Frequency...
Phase noise is of importance in OFDM systems, since it generates intercarrier interference and general system performance degradation. In this paper we analyse the accuracy of maximum likelihood estimation of the phase noise bandwidth for OFDM systems. We utilize the auxiliary functions used in the EM algorithm to obtain an expression for the Fisher information matrix. Our key conclusion is that it...
Underlay ultra wideband (UWB) systems have to be able to detect the presence of primary systems operating in the same band for detect-and-avoid (DAA) operation. In this paper, the performances of joint and independent detection of multiple primary systems are investigated assuming that the primary systems are potentially dependent (e.g., frequency division duplex uplink-downlink communications). Joint...
This paper investigates OFDMA downlink resource (spectrum and power) sharing algorithms for fixed relay stations. Iterative waterfilling is used in the power allocation process and shown to result in an optimal power allocation solution for multiple-relay networks. Iterative waterfilling is then developed with a power reallocation process to achieve more efficient spectrum utilization. Furthermore,...
This paper focuses on the Physical Downlink Control Channel (PDCCH) and describes the impact of its realistic constraints. Specifically, the impact on the performance of the UTRAN LTE FDD downlink and on the QoS provisioning is studied. It is described, when adopting a QoS-aware packet scheduling policy, how scheduling limitations due to control channel may affect the scheduler behavior. It is shown...
In this paper, both distributed and adjacent subchannelization modes for WiMAX system based on IEEE 802.16d standard are investigated. Sensitivity to the co-channel interference is evaluated for each mode in downlink communications. We provide a comparative analysis in terms of spectrum efficiency and present a new scheme to enhance the system performance. Our solution proposes a joint deployment...
Cooperative joint transmission and detection algorithms have a high potential to increase the capacity of cellular radio systems. This paper investigates efficient network layer protocols to realize such cooperation over a heterogeneous, bandwidth-limited backhaul. Target systems are MIMO-OFDM cellular communication systems with flat hierarchy (no central unit), and we take 3GPP LTE as example. The...
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.