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 performance of MMSE Single-user Detection (SD) and Multi-user Detection (MD) STBC MC-CDMA systems are analysed and compared in the case of two transmit antennas and one or two receive antennas over Rayleigh fading channels and then over the stochastic MIMO METRA channel model. With two transmit and one receive antennas, MD achieves a gain of roughly 1 dB for non-full load systems while the same...
Multiple algorithms have been proposed to deal with the high Peak to Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) signals. The second generation of Digital Video Broadcasting for Terrestrial transmission (DVB-T2) has adopted the Tone Reservation (TR) technique. It is based on an iterative process where, at each iteration, a predefined kernel is used to reduce one...
In this paper, we consider a cognitive radio (CR) link operating in a spectrum sharing (SS) mode with a primary network. In this mode, the primary and secondary users can share the same frequency band as long as the interference caused by the secondary network on the primary network is properly regulated. The optimal ergodic capacity of the secondary link that can be achieved is hence being investigated...
In this paper, the ergodic capacity maximization problem in case of coexistence between digital video broadcasting (DVB) and long term evolution (LTE) systems is studied. A full interference scenario, i.e. where the DVB and LTE systems spectrally overlap, is assumed. The objective function, defined as the summation of the LTE and DVB system capacities, is shown to be constituted by a convex and concave...
The DVB-S2 standard has been revealed a reliable standard for data transmission thanks to the LDPC codes. The waterfall of the bit-error rate is very abrupt to reach low values of order 10^(-10) in the error floor. In this paper, we propose a novel investigation on the iterative decoding of these codes by the Belief Propagation algorithm on Gaussian channels. Introducing definitions of persistent...
Orthogonal Frequency Division Multiplexing (OFDM) systems are characterized by a high Peak to Average Power Ratio (PAPR), which results in performance degradation due to High Power Amplifiers' nonlinearities. Multiple algorithms have been proposed to deal with this problem, among them the Tone Reservation (TR) technique adopted in the second generation of Digital Video Broadcasting for Terrestrial...
In this paper, we focus on the behavior of the Belief Propagation (BP) algorithm when decoding the Low-Density Parity-Check (LDPC) code of rate 3/4 in the DVB-S2 standard. By studying the topological structure of its Tanner graph, we raise properties inherent to the degree distribution that turns out to be strongly correlated with the decoding failures. The irregularity of the degrees seriously damages...
In this paper, we analyze the problem of deploying small cellular cells into a large broadcast cell in the framework of the convergence between the Long Term Evolution (LTE) and the Digital Broadcasting Video (DVB) technologies. In this work, a non- cooperative deployment of these technologies is considered in the sense that cellular and broadcast networks interfere on each other. In literature, there...
In a series of previous related works, a joint Channel Estimation and Peak-to-Average Power Ratio (PAPR) (CEPR) based on shifted and superimposed sequences (FS-CEPR) for Orthogonal Frequency Division Multiplexing (OFDM) has been addressed by some authors of this paper. While the FS-CEPR techniques have proven its efficiency in terms of PAPR reduction, the channel estimation requires an additional...
The emerging IEEE 802.11ac standard introduces spatial division multiplexing access, in its downlink version, to the wireless local access world. Through this multi-user multiple input multiple output (MU-MIMO) technique the access point (AP) can simultaneously transmit multiple independent groups of streams to different stations. The consequent precoding requires precise channel knowledge and thus...
In a series of previous related works, a joint Channel Estimation and Peak-to-Average Power Ratio (PAPR) (CEPR) for Orthogonal Frequency Division Multiplexing (OFDM) has been addressed by some authors of this paper. While the performance evaluation in terms of PAPR reduction and channel estimation have been widely investigated in these works, the complexity of the CEPR technique was shortly evaluated...
Most of studies dealing with single user multiple input multiple output (SU-MIMO) and multiple user MIMO (MU-MIMO) rely on physical (PHY) layer only or medium access control (MAC) layer only simulations. In the first case, the apparent considerable performance gains enabled by space division multiple access (SDMA) in downlink transmissions are often obtained without taking into account sounding and...
A novel distributed space-time block code (STBC) for the next generation mobile TV broadcasting is proposed. The new code provides efficient performance within a wide range of power imbalance showing strong adaptivity to the single frequency network broadcasting deployments. The new code outperforms existing STBCs with equivalent decoding complexity and approaches those with much higher complexities.
In this paper, we address the performance of joint Peak-to-Average Power Ratio (PAPR) reduction and channel estimation schemes. The target of this work is multifold. First, we propose a novel PAPR reduction scheme for Orthogonal Frequency Division Multiplexing (OFDM) systems: instead of using dedicated pilots for PAPR reduction as with Tone Reservation (TR) method existing in the literature, we propose...
The growth in energy demand coupled with global warming provide new trends in communication systems known as green radio. The main focus in green radio is to provide new techniques to save energy consumption. In this paper, a new concept, named ultra wide time (UWT), is proposed to define the lower asymptotic consumed energy to transmit a given amount of information. With UWT concept, minimization...
In this study, the author propose a new method called coset partitioning to generate easily and efficiently the best space-time trellis codes (STTCs), thereby reducing considerably the usual important search time. This method, used in the case of 2n-PSK STTCs, is an extension of the set partitioning proposed by Ungerboeck based on the coset and lattice Calderbank's approach. The main guideline of...
In contrast to the classical cyclic prefix (CP)-OFDM, the time domain synchronous (TDS)-OFDM employs a known pseudo noise (PN) sequence as guard interval (GI). Conventional channel estimation methods for TDS-OFDM are only based on the PN sequence and consequently suffer from intersymbol interference. This paper proposes a novel two-stage channel estimation method which combines the estimation results...
The conventional resource allocation method in multicast OFDM systems adapts the physical layer to the worst user link conditions. In this paper, we propose new subcarrier, bit and time slot allocation algorithms for multicast OFDM systems in indoor powerline communication (PLC) context. To increase the multicast bit rate, these algorithms jointly use linear precoded OFDM (LP-OFDM) modulation technique...
Linear precoding (LP) technique applied to OFDM systems has already proved its ability to significantly increase the system throughput in a powerline communication (PLC) context. In this paper, we propose resource allocation algorithms based on the LP technique to increase the multicast OFDM systems bit rate. The conventional multicast capacity is limited by the user which experiences the worst channel...
The classical channel estimation method in TDS-OFDM is carried out based on the PN sequence in the GI which suffers from the intersymbol interference of the previous OFDM data symbols. This paper presents a novel data-aided channel estimation method to refine the initial channel estimation obtained from PN sequence. The data symbols are rebuilt based on the log-likelihood ratio (LLR) from the output...
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.