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, the resources allocation for the Orthogonal Frequency Division Multiple Access (OFDMA) based two-hop relay network is addressed. Due to a high degree of users mobility, the Base Station is assumed to have only a statistical knowledge of the users channels. Based on the outage capacities connected to the user rates, a relay selection, sub-carrier and power allocation method that minimizes...
We consider multi-hop decode-and-forward relaying OFDM systems in this paper. All the relay nodes are assumed to be regenerative and working in half-duplex mode. We propose adaptive power allocation (PA) algorithms to maximize the overall system capacity and minimize the system outage probability, respectively. Simulation results show that the proposed algorithms outperform the existing PA algorithms...
In this paper we present two strategy to maximize user's throughput in Cooperative MU-OFDM network while considering fairness of users. Our strategy is proposed to improve throughput and fairness of users only with limited feedback. With perfect instantaneous channel state information(CSI) at receiver, the resource allocating strategy not only decided in base station, but also decided in users of...
Relaying is one of the key techniques considered by the 3GPP LTE-Advanced as part of 4G cellular technologies, aiming to increase the coverage and capacity of the network especially for the edge nodes. In this work, we have considered the uplink scheduling of an LTE network with the help of positioned relay nodes. We have projected the entire problem as a constrained optimization problem. As a solution,...
In this paper, we present a low-complexity power allocation scheme for non-regenerative (amplify and forward) relaying in cognitive radio systems. The main objective of the power allocation is to maximize the signal to noise ratio (SNR) at the destination under the constraint of acceptable interference to the primary users (PU). In this paper, we propose an iterative power allocation using SNR upper...
This paper considers an OFDMA relay network and proposes an auction algorithm for the subchannel allocation to balancing efficiency and fairness with service differentiation. This algorithm allows users to fairly compete for the using of the subchannel through a new bidding strategy. We use the second-price sealed auction mechanism under which the dominant strategy of the bidder is bidding the true...
This paper addresses the filter design and user selection issues for the downlink of a multi-user MIMO-relay system. To eliminate interuser interference, the filter design is based on the singular value decomposition (SVD) of the first hop link and block-diagonalization (BD) for the second hop link. Then the problem is converted to the power allocation problem at the relay station (RS). It can be...
This paper considers a two-hop orthogonal frequency division multiple (OFDM) wireless communication systems with a source, a decode-and-forward (DF) relay and a destination. We develop a low complexity rate adaptive power allocation strategy at the source and the relay, with respect to individual transmit power constraints, if the channel state information at the transmitter is given. To further enhance...
In this paper, we study resource allocation and relay selection in a decode-and-forward downlink OFDMA cooperative network assuming imperfect channel state information (CSI) at the base station (BS). We assume that due to feedback delay, the BS has only outdated CSI of BS to users and inter-user links. We propose a centralized optimization framework in which the BS takes decisions on the basis of...
Most existing works on resource allocation in cooperative OFDMA systems have focused on homogeneous users with same service and demand. In this paper, we focus on resource allocation in a service differentiated cooperative OFDMA system where each user has individual QoS requirement. We investigate joint power allocation, relay selection and subcarrier assignment to maximize overall system rates with...
This paper presents a two-stage power allocation for the distributed GABBA space-time coded amplify-and-forward (AF) cooperative networks . The new power allocation scheme first determines the transmit power between the source node and the relay nodes by maximizing the instantaneous rate, and thereafter optimizes the power distribution among the relay nodes via the watering filling. Moreover, a maximum-likelihood...
We consider a multiple-input multiple-output (MIMO) system assisted by multiple non-regenerative single-antenna relays. This system where the antennas of all the relays are distributed geographically is fundamentally different from a single relay case with multiple antennas. The optimal power allocation for a relay with multiple antennas has already been known. In that solution, the power is distributed...
This paper investigates the power control problem for parallel amplify-and-forward OFDM relaying networks under hybrid power constraints across relays. Based on the concavity of the objective function, an iterative algorithm, which definitely converges to the optimal solution, is firstly proposed for the special case where the aggregate constraint could be ignored. Then, for the general case where...
This paper focuses on the adaptive resource allocation strategies for two-hop multiuser OFDMA nonregenerative relay networks considering both maximization of total throughput and fairness constraints among users. First, an optimal resource allocation scheme to maximize the overall data rate is developed with separate transmit power constraints both at source and relay nodes. An alternative scheme...
This paper investigates proportional fairness-oriented scheduling issues for multihop OFDMA systems with multiple relays. Based on the idealized L-hop linear network model, three adaptive proportional fair scheduling (PFS) algorithms, namely optimal PFS, iterative user pairing (IUP) PFS and successive distributed (SD) PFS, are proposed for multihop OFDMA systems. Different with the existing scheme...
In this paper, we tackle an important problem in WiMAX relay networks called Multicast Recipient Maximization (MRM), which maximizes the number of multicast recipients with given budget. To deal with this problem, a novel resource allocation scheme called Dynamic Station Selection (DSS) is proposed. We prove that MRM is NP-hard, while our DSS has polynomial-time computational complexity. The simulation...
In this paper, we propose an economics-based, distributed multicast scheme for wireless relay networks. Our goal is to construct efficient multicast routes that serve as many users as possible with the given bandwidth budget. The proposed scheme, called Price-Based Distributed Allocation (PBDA), allows each node to make decisions independently. Through analysis, we prove that the original problem...
In this paper we focus on the subcarrier allocation for the uplink OFDMA based cooperative relay networks. Multiple cells were considered, each composed of a single base station (destination), multiple amplify and forward (AF) relay stations and multiple subscriber stations (sources). The effects of inter-cell interference (ICI) have been considered to optimize the subcarrier allocation with low complexity...
This paper investigates joint power and subcarrier allocation issues for cellular OFDM-relay networks. Two novel decentralized schemes, namely semi-distributed method and distributed method based on multihop equilibrium are proposed, which aims to exploit the radio resource management (RRM) function for relay nodes (RNs) and decrease the amount of feedback information for RN-MS links. In decentralized...
We study an integrated multiflow network model, in which physical-layer rate control and link-layer medium access and routing decisions are jointly optimized. In particular, we explore the challenges involved in incorporating the three-terminal cooperative paradigm into such a broader resource allocation problem. We present several methods for defining cooperative units within the larger network,...
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.