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The resource allocation problem for the downlink of Orthogonal Frequency Division Multiple Access (OFDMA) wireless multicast systems is investigated. It is assumed that both the Base Station (BS) and each user are equipped with a single antenna and the allocation unit is not the subcarrier, as in conventional OFDMA systems, but a set of contiguous subcarriers (chunk). The aim of the proposed efficient...
In this paper we address the challenge of multiuser scheduling in the downlink of 3GPP UMTS/LTE. Long Term Evolution (LTE) imposes the constraint of using the same code rate, modulation order and transmit power for all resources a User Equipment (UE) is scheduled onto. This, in addition to the lack of channel knowledge, prohibits theoretical concepts such as capacity maximization to be applied for...
In a Multiple Input Multiple Output (MIMO) architecture, self-interference becomes the dominant source of impairment, particularly when correlation exists between spatial sub-channels. This paper aims to minimize the effect of self-interference by means of dynamic subcarrier allocation (DSA) and exploiting the knowledge of spatial sub-channel `quality' evaluated by an ESINR metric. The proposed system...
In this paper an adaptive resource allocation algorithm in OFDMA based cognitive radio (CR) system is proposed that not only meets the quality of service (QoS) of real-time (RT) services but also increases the dynamic capacity of the system. In contrast to existing algorithms for multi-user OFDM systems which are unable to guarantee maximum sum data rate when applied to CR system in real-time, the...
Orthogonal frequency division multiple access (OFDMA) has been used for broadband wireless multiple access. The performance of OFDMA system can be improved by using multiple antennas with space time coding to get transmit and receive diversity. Channel information estimated at receiver for space time decoding can be used for sub-channels allocation at transmitter. In this paper, we propose a method...
This paper proposes a cooperative game theoretic resource allocation scheme for downlink OFDMA wireless networks. We define a user??s payoff as a function of his data throughput. Then the source allocation can be modeled as a cooperative game to maximize the aggregate payoff of the users. To achieve the Nash bargaining solution (NBS) of the game, a suboptimal subcarrier allocation is first performed...
Adaptive radio resource allocation mechanisms exploiting the inherent frequency selectivity of the wireless medium as well as the multi-user effect are expected to play a key role in emerging next generation OFDMA-based wireless networks. Although a plethora of studies concerning either constant/guaranteed bit rate (CBR/GBR) or variable bit rate/best effort (VBR/BE) traffic has been published to date,...
We address the problem of resource allocation on an OFDMA downlink under fairness constraints with limited channel state information (CSI). Target QoS corresponds to a minimum user data rate, a target bit-error rate and a maximum outage probability. The only available CSI is the channel average gain of each user. This partial CSI can be viewed as a shadowed pathloss that yields a modified user distribution...
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