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.
Reducing the consumed energy in wireless communication systems has a direct impact on operational expenditure as well as CO2 emissions. With increasing interest in multimedia applications and high data rate services, environmentally sustainable communications networks must reduce the energy per delivered bit at an equal rate, if not better. This paper addresses downlink energy-efficient transmission...
The Lyapunov drift based back-pressure framework is applied to the cognitive radio context. A group of spatially distributed sensing units are utilized to monitor re-used spectrum. The sensing results for secondary user received power are utilized in virtual interference queues that, when stabilized, enforce spatially point-wise received power constraints, given in terms of a maximum allowed rate...
In this paper we describe an LTE based demonstrator of the Universal Link Layer API (ULLA) and Cognitive Resource Manager (CRM) modules that are developed in ARAGORN project. The demonstrated LTE system comprises one LTE TDD eNode B and one User Equipment (UE). We first introduce ULLA and CRM framework and then demonstrate their suitability to be implemented with the existing LTE equipments. We show...
In a heterogeneous cellular networks environment, users behaviour and network deployment configuration parameters have an impact on the overall Quality of Service. This paper proposes a new and simple model that, on the one hand, explores the users behaviour impact on the network by having mobility, multi-service usage and traffic generation profiles as inputs, and on the other, enables the network...
A two-way relay channel with independent parallel Gaussian channels between the relay and the two terminals is considered. Focusing on the decode-and-forward protocol, the second phase of the communication, in which the relay broadcasts the two messages to their respective receivers, is studied. Precisely, the problem of computing the power allocation among the parallel channels that maximizes the...
Cognitive wireless mesh networks have great potential to green communication. One of the critical challenges for realizing such networks is how to adaptively match transmit powers and allocate frequency resources among secondary users of the licensed frequency bands whilst maintaining the quality-of-service (QoS) requirement of the primary users, even in mutually entangled interferences environment...
This paper proposes a slot-based persistent allocation scheme which allows WiMAX base stations (BSs) allocating resources to VoIP-like traffic in an efficient way. The proposed scheme firstly scans resource slots within the stream of data frames to identify an available resource slot for a persistent resource allocation. To facilitate the scanning process, the base station maintains a tree structure...
We propose a cross-layer strategy that jointly optimizes user scheduling and resource allocation for adaptive modulation and coding (AMC) based orthogonal frequency multiple access (OFDMA). The objective of this paper is to maximize the system throughput as a function of the bit error rate (BER) and the spectral efficiency based on selected modulation and coding schemes (MCSs). The proposed optimal...
Recently, the concept of self-organization has drawn considerable attention for its possible use in distributed interference management. To realize self-organized interference management, a minority game (MG) is a promising tool because it facilitates self-organized decision-making. Although the existing interference management scheme that involves the use of an MG achieves transmission control aware...
Relaying is generally considered as a method to ensure capacity improvement and coverage extension in cellular systems. The additional communication traffic between a mobile station and a relay intermediately inserted into a link between RUE and BS requires additional considerations on HARQ protocol. In this paper, we propose a method to jointly and dynamically balance the maximum number of transmissions...
Attention to resource allocation algorithms for multiservice Code Division Multiple Access CDMA networks has focused on algorithms maximizing the uplink aggregate throughput. In the present paper we address the problem of the joint power and spreading factor (SF) allocation to non real-time (NRT) terminals on the uplink, once real time constraints are satisfied. An optimal algorithm is proposed, that...
The goal of our work is to limit in-band interference in wireless communication systems. Based on a three-regime interference classifier, we propose a novel distributed inter-cell power allocation algorithm where each cell computes by an iterative process its minimum power budget to meet its local quality of service (QoS) constraints. Analytical results show how our proposal permits to notably reduce...
A dynamic symbol mapping technique is proposed for downlink and point-to-point multiple input multiple output (MIMO) systems. The proposed mapping introduces a perturbation to the transmitted symbols by adaptively changing the order or the values of the symbols to be transmitted within a sub-frame of symbols with the objective to enhance the received symbols' power. The symbol mapping aims at taking...
This paper details the current work status of the ETSI Reconfigurable Radio Systems (RRS) Technical Committee (TC) and gives an outlook on the future evolution. While previous publications have presented an overview of ETSI RRS' main working axes related to i) Cognitive Radio System Aspects, ii) Radio Equipment Architecture (including a Cognitive Pilot Channel (CPC) proposal and a Functional Architecture...
This paper considers the downlink of a cellular orthogonal frequency division multi-access (OFDMA) system, in which multiple base stations (BSs) are coordinated by a centralized resource allocation algorithm. We address the problem of maximizing the weighted sum of the minimal user rates (WSMR) of coordinated cells subject to a total power constraint at each BS. In particular, the solution of this...
Amplify-and-forward (AF) is one of the most popular and simple approaches to transmit information over a cooperative multi-input multi-output (MIMO) relay channel. In this paper, we propose three novel power allocation methods for the downlink of cooperative multi-user MIMO AF system, which are designed to maximize the weighted sum-rate (WSR) of the cooperative system, by considering two different...
This paper presents an efficient and fair uplink resource allocation algorithm in multicarrier based cognitive radio systems. The proposed resource allocation is divided into two steps. The subcarriers to user assignment is first performed and then the power is allocated to the different subcarriers. The subcarriers are allocated based on the channel quality, amount of interference imposed to the...
The throughput of conventional wireless multicast systems is limited by the multicast user with the lowest channel quality, which leads to a very low throughput especially if the number of users is large. In this paper, we show that hybrid-automatic repeat request with Chase combining (HARQ-CC) is a promising technique to overcome this problem and optimize the transmission rate of wireless multicast...
Femtocells are being deployed for coverage extension and higher data rates. However, interference problem between macrocell and femtocells should be solved before massive deployment. In this paper, we analyze the possible cases of frequency resource allocation in the OFDMA femtocell systems using Fractional Frequency Reuse (FFR) in order to minimize the interference between both cells. Under the assumed...
As the traffic grows rapidly in wireless communication, the spectrum becomes scarce. The current inefficient fixed spectrum allocation schemes will not satisfy the growing spectrum demand. This paper proposes a double auction based dynamic spectrum sharing scheme for multiple operators adopting OFDMA in the downlink. More specifically, this scheme allows free subcarriers trading between operators...
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.