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.
We devise novel techniques to obtain the downlink power inducing a given load in long-term evolution (LTE) systems, where we define load as the fraction of resource blocks in the time-frequency grid being requested by users from a given base station. These techniques are particularly important because previous studies have proved that the data rate requirement of users can be satisfied with lower...
In heterogeneous cellular networks (HetNets) for mobile communications, small cells are deployed within the coverage range of primary macro cells to provide for a localized capacity boost in traffic hotspots. The sharing of communication channels among the macro-cell and the small-cell tiers is spectrally efficient but causes failures of control signaling in LTE networks due to unmitigated co-channel...
This paper presents the theoretical capacity performance of different linear multi-user MIMO (MU-MIMO) pre-coding algorithms for a millimeter wave communication system using hybrid beam-forming. Hybrid beam-forming uses both RF and digital beam-forming and is a practical way to achieve the required array gains when the high bandwidths available at millimeter wave frequencies are utilized. The performances...
In this paper, we present a practical Dirty Paper Coding (DPC) scheme using sum codes based on LDPC codes. While a typical sum-code-based DPC scheme uses a constrained decoder as part of the encoding operation, such an approach fails in the case of LDPC codes since the constrained decoder based on a standard LDPC decoder tends to get stuck at highly suboptimal points in typical scenarios. We get around...
This paper presents a unifying and systematic framework to solve wireless max-min utility fairness optimization problems in multiuser wireless networks with generalized monotonic constraints. These problems are often challenging to solve due to their nonlinearity and non-convexity. Our framework leverages a general result in nonlinear Perron-Frobenius theory to characterize the global optimal solution...
Reduction of the out-of-band (OOB) emission is essential for Cognitive Radio (CR) systems to enable coexistence with licensed (primary) systems operating in the adjacent frequency bands. This paper proposes an algorithm for the Non Contiguous Orthogonal Frequency Division Multiplexing (NC-OFDM)-based CR, to reduce the interference caused by both OOB radiation and by non-ideal frequency selectivity...
While the information theoretic result commonly referred to as “dirty paper coding” [1] has been known for long, it has not led to practical schemes that can be implemented easily in real-life communication systems. In this paper, we present the concept of sum codes and show how they provide a convenient platform for dirty paper coding. Comb-combined sum codes, which provide a convenient method of...
Although the information theoretic result referred to as “dirty paper coding” [1] has been known for quite a while, it has not led to schemes that look attractive enough for real-life communication systems. In a companion paper [2], we presented the concept of sum codes and showed how they provide a convenient platform for interference suppression via dirty paper coding. In this paper, we present...
In this paper, we propose three different user selection methods for an OFDM based downlink closed loop multi-user MIMO cellular system. The first method is based on the maximization of orthogonality, the second on the maximization of alignment gain and the third on the maximization of post receiver SINR (estimated by the transmitter). To analyze the influence of these methods on downlink transmission,...
The knowledge of interference plays a positive role in enhancing the secrecy of Gaussian wiretap channels. We address this fact using a linear deterministic model to explicitly show the interplay between different channel parameters. This evokes a coding scheme which leverages the knowledge of the interfering sequence to confuse the eavesdropper without compromising the decoding at the legitimate...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
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.