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Nowadays, the emergence of many radio technologies has increased the research interest towards Radio Resources Management (RRM) in heterogeneous systems. In this context, we seek a distributed scheme for discrete resource allocation. The algorithm proposed should reduce computation and signalling overhead, compared to centralized optimization or distributed solutions based on Game Theory. Therefore,...
Linear precoded discrete multitone modulation (LP-DMT) system has been already proved advantageous with adaptive resource allocation algorithm in a power line communication (PLC) context. In this paper, we investigate the bit and energy allocation algorithm of an adaptive LP-DMT system taking into account the channel coding scheme. A coded adaptive LP-DMT system is presented in the PLC context with...
This paper presents results of ergodic capacity of frequency selective multipath fading channels with path correlations. The exact capacity expression is derived. The main result establishes that, for the uncorrelated case, the ergodic capacity does not depend on either the number of taps or the power delay profile of the channel. However when tap correlation is taken into account, this statement...
In this paper we investigate the issue of power control and subcarrier assignment in an OFDMA downlink system impaired by multicell interference. As done in Wimax, we assume that a certain part of the available bandwidth is likely to be reused by different base stations (and is thus subject to multicell interference) and that an other part of the bandwidth is used by one base station only (and is...
In multi-user multiple-input multiple-output (MU-MIMO) systems, spatial multiplexing can be employed to increase the throughput without the need for multiple antennas and expensive signal processing at the user equipments. In theory, MU-MIMO is also more immune to most of propagation limitations plaguing single-user MIMO (SU-MIMO) systems, such as channel rank loss or antenna correlation. In this...
This paper develops the optimal power-allocation algorithm to maximize the sum-rate in orthogonal frequency-division multiple-access (OFDMA) regenerative relaying downlink systems with separate power constraints. The optimal algorithm is based on the Lagrange dual-decomposition method when subchannels are pre-assigned to users and relay stations (RS). This paper also proposes a heuristic algorithm,...
This paper studies the downlink multiuser multiple input multiple output-orthogonal frequency division multiple access (MIMO-OFDMA) system for margin adaptive multiuser eigenmode transmission (MET) with perfect channel state information at the transmitter. In margin adaptive objective, base station (BS) has to satisfy individual quality of service (QoS) constraints of the users subject to transmit...
Average consensus algorithms have attracted popularity in the wireless sensor network scenario as a simple way to compute linear combinations of the observations gathered by the sensors, in a totally decentralized fashion, i.e., without a fusion center. However, average consensus techniques involve the iterated exchange of data among sensors. In a practical implementation, this interaction is affected...
In this paper we analyze the performance of wireless ad hoc networks with outage constraints. Using the performance metric aggregate information efficiency, we study the relationship among spectral efficiency, interference immunity, link activity and outage probability. We propose a numerical procedure to estimate the outage probability in a network as a function of several network parameters. Numerical...
Multi-carrier modulations such as orthogonal frequency division multiplexing (OFDM) are widely used in radio transmission systems. Among these modulations, OFDM/OQAM is an interesting alternative to the conventional cyclic-prefix, OFDM (CP-OFDM) modulation, as it does not require the use of any guard interval. This specificity allows a better spectral efficiency. In this paper we investigate on channel...
In this paper we deliberate on channel coding for spatial data streams and focus on their equal-rate non-uniform power distribution in successive interference cancellation (SIC) detection algorithm. We focus on high spectral efficiency bit interleaved coded modulation (BICM) MIMO OFDM system where, after serial to parallel conversion, per antenna coding and antenna cycling, spatial data streams are...
The concept of cognitive radio has recently received great attention from the researcherspsila community as a promising paradigm to achieve efficient use of the frequency resource by allowing the co-existence of licensed (primary) and unlicensed (secondary) users in the same bandwidth. In this paper we propose and analyze a totally decentralized approach, based on game theory, to design cognitive...
The half-duplex multiple relay-assisted channel is investigated, where the relays work under decode-and-forward (DF) in time/frequency orthogonal resources. Achievable rates are optimized with respect to the transmitted powers and with respect to the fraction of time/bandwidth allocated to the relay-receive and the relay-transmit phases. Different transmission strategies associated to different complexities...
A cross-layer approach, called CoopMAC, has been proposed recently to integrate cooperation at the physical layer with the medium access control sublayer, thereby achieving substantial throughput and delay performance improvements. CoopMAC capitalizes on the broadcast nature of wireless channels, recruiting a relay opportunistically and on the fly to support the communication of a particular source-destination...
We consider a cognitive radio scenario where a primary and a secondary user wish to communicate with their corresponding receivers simultaneously over frequency selective channels. Under realistic assumptions that the primary user is ignorant of the secondary userpsilas presence and that the secondary transmitter has no side information about the primarypsilas message, we propose a Vandermonde precoder...
In the framework of cognitive radio, electro-magnetic environment sensing is a crucial task. In order to distinguish various systems relying on OFDM modulations from each others (such as WiMAX, WiFi, DVB-T), we need to be able to estimate precisely the inter-carrier spacing used in the transmitted signal. When the ratio between cyclic prefix and OFDM symbol duration is small or when the multipath...
In this paper, we consider a receiver setup with fewer analog to digital convertors (ADCpsilas) than antennas. An analog preprocessing network (APN) is placed before the ADCpsilas to reduce power consumption in the receiver. A set of low resolution beamformers is used to design the APN and cancel contributions of interfering users. Simulation results show that introduction of such APN design algorithms...
In this paper, we propose a robust novel approach with closed-form estimator for object tracking based on a non-linear measurement model over time from a single sensor with arbitrary noise degradation. Relying on the widely-used dynamic motion model for arbitrary moving targets, tracking of moving objects can be formulated using received signal strength (RSS) measurements. We provide a closed-form...
We propose a new simple and accurate approach to estimate the Doppler spread which is a key parameter in the context of wireless communication systems. This new approach stems from the well known fact that the crosscorrelation of the channel is a weighted summation of monochromatic plane waves (or inverse Fourier transform of its power spectral density). In the case of Doppler spread, these plane...
In this paper, we propose a decoupled root-MUSIC algorithm adapted to the multidimensional harmonic model, which is widely used in MIMO channel sounding. The optimization criterion of the proposed algorithm is based on multidimensional orthogonal condition testings between a tensor steering manifold parameterized by the parameters of interest and a set of orthogonal projectors associated with each...
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