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.
In this paper, we investigate the spectrum scheduling problem for next generation multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) systems under QoS and interference constraints. Based on a constrained optimization problem formulation, we propose a cross-layer scheduling solution that takes into account the unlicensed UWB users channel and QoS conditions as well...
It is well-known that wireless scheduling algorithm could exploit multi-user diversity to enhance the network capacity. With multiple transmit/receive antennas, there are additional degrees of freedom which could deliver either spatial multiplexing gain and/or spatial diversity gain. With cross layer scheduling, there is also multi-user selection diversity which contributes to both network capacity...
Recently, a strong demand on high data rate wireless communication can be observed. The development of multi-gigabit wireless transmission systems has become very attractive. For achieving such data rates, the exploitation of 60 GHz mm wave is a very promising technical approach and has been adopted in IEEE 802.15.3c. Except for physical layer (PHY) designs, the Medium Access Control (MAC) layer design...
In this paper, we investigate the training problem of wireless local area networks (WLANs) with downlink multi-user multiple input multiple output (DL MU MIMO) capability. We extend the 802.11 MAC protocol and propose a few training protocols at the MAC layer to support DL MU MIMO. We provide a capacity analysis based on measurement results from an 802.11n systems, evaluate the overhead of these training...
The LOS components of the base station (BS) can provide a high SNR to mobile stations (MSs), but they cannot achieve a high spatial multiplexing gain in the MIMO-OFDMA system. The spatial multiplexing gain is obtained by degrees of freedom between MIMO antenna arrays. MIMO channels should be uncorrelated to achieve the maximum degrees of freedom, and it depends on rich scattering environments which...
This paper investigates the impact of realistic antennas on joint anchor-less localization and indoor characterization based on Impulse Radio (IR) Ultra Wideband (UWB) communications. In this frame, the Maximum Averaged Likelihood (MAL) algorithm and its extended version are considered, both relying on a tree approach consisting in two stages. The first part of the process, which is common to both...
In many wireless systems, the energy consumed by the receiver is significantly larger than the energy consumed by transmitter, possibly even by orders of magnitudes. This paper derives an analytical solution to maximize the throughput per unit of available receiver circuit power. Adaptive control of the IP3, to handle the time-varying adjacent channel interference level, can substantially improve...
In this paper, we propose an innovative low-cost biometric authentication scheme based on uniformed Gaussian mixture model (GMM) for secure communications within wireless body area sensor networks (WBASNs), to obviate the cost-prohibitive key exchange problem. In this approach, the sender Inter Pulse Interval (IPI) information is selected as the biometric key for authentication, and a statistical...
This paper investigates a communication system where three terminals exchange their information with each other with the help of a relay. One joint network and channel coding (JNCC) scheme (based on iterative soft information exchange between channel and network decoder) and one separate network and channel coding scheme based on turbo codes are proposed. The outage behavior of the presented systems...
In this paper, an efficient Decode-and-Forward (DF) relay selection scheme for interference-limited relaying networks is considered. In contrast to previously reported works, we consider multiple interferences which make the conventional relay selection schemes not suitable for interference-limited networks and propose a new relay selection scheme for DF protocol with multiple interferences. Approximate...
Perfect Space-Time Codes (STC) are full-rate, full-diversity codes originally proposed for Multiple Input Multiple Output (MIMO) systems. Based on Cyclic Division Algebras (CDA), they have non-vanishing determinants and hence achieve the Diversity-Multiplexing Tradeoff (DMT). In addition, these codes have led to optimal distributed Space-Time Codes when applied in cooperative networks under the assumption...
We derive closed form expressions for the second-order statistics of the spectral power gain of wide-band microwave indoor channels. We obtain our results within a framework general enough to be compatible with several popular channel models, such as those proposed by the IEEE 802.15.3a task group, as well as the Saleh-Valenzuela channel model. As all these models, our channel description is based...
This paper derives an exact, easily computable series-type formulation for the multivariate α-μ joint cumulative distribution function. Then, based on useful and practical assumptions, alternative, new, simpler formulations for the α-μ multivariate joint density function and its corresponding distribution function are provided. The formulations are still general and yet very simple, assuming arbitrary...
The performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relaying network over Rayleigh-fading channels is analyzed. Assuming that the source, destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form cumulative distribution function (CDF) of received signal-to-noise...
The combination of Multiple-Input Multiple-Output (MIMO) with Orthogonal Frequency Division Multiplexing (OFDM) is a promising technique for achieving high performance with very high data rates in 4G broadband wireless communications. Nevertheless, one major disadvantage of MIMO-OFDM systems lies in a prohibitively large Peak-to-Average Power Ratio (PAPR) of the transmitted signal on each antenna...
In this decade, peer-to-peer (P2P) applications have emerged as popular tools for sharing data and they have gained much attention. Such P2P applications build overlay networks on top of existing infrastructure networks and disseminate data in a peer-to-peer manner. How well the P2P overlay network maps onto the underlying physical network topology can significantly impact P2P application performances...
Many new broadband, emerging applications such as high definition 3D video streaming or on-line gaming are going to be part of the future home. Current home networks are still not capable to cope with the tight requirements asked by these kind of applications. Moreover, many underlying wired and wireless transmission technologies are available, but no solution to reach a convergent framework is available...
In this paper, we assess the random coding error exponents (EEs) corresponding to decode-and-forward (DF), compress-and-forward (CF) and quantize-and-forward (QF) relaying strategies for a parallel relay network (PRN), consisting of a single source and two relays. Moreover, through numerical analysis we show that the EEs achieved by using QF relaying along with non-Gaussian signaling (coded modulation,...
In this paper, we propose an analytical framework on the exact computation of the average capacity of multihop transmission over amplify-and-forward relay fading channels. Our approach relies on the algebraic combination of Mellin and Laplace transforms to obtain exact single integral expressions which can be easily computed by Gauss-Chebyshev Quadrature (GCQ) rule. As such, the derived results are...
In view of the new feature after introducing the relay nodes (RNs) into the conventional cellular networks, a novel soft frequency reuse (SFR)-based inter-cell interference coordination (ICIC) scheme is proposed in the relay enhanced cellular networks. On the basis of original ICIC scheme for conventional cellular network, RNs in the proposed SFR scheme reuses part of neighboring cell-edge bands to...
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.