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**1 - 3**of**3**### Dynamic Allocation of Subcarriers and 1 Transmit Powers in an OFDMA Cellular Network

"... This paper considers the problem of minimizing outage probabilities in the downlink of a multiuser, multicell OFDMA cellular network with frequency selective fading, imperfect channel state information and frequency hopping. The task is to determine the allocation of powers and subcarriers for users ..."

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This paper considers the problem of minimizing outage probabilities in the downlink of a multiuser, multicell OFDMA cellular network with frequency selective fading, imperfect channel state information and frequency hopping. The task is to determine the allocation of powers and subcarriers for users to ensure that the user outage probabilities are as low as possible. We formulate a min-max outage probability problem and solve it under the constraint that the transmit power spectrum at each base station is flat. In particular, we obtain a subchannel allocation algorithm that has complexity O(L log L) in L, the number of users in the cell. We also consider suboptimal but implementable approaches with and without the flat transmit power spectrum constraint. We conclude that the flat transmit spectrum approach has merit, and warrants further study. Index Terms Cellular network, resource allocation, power control, orthogonal frequency division multiple access (OFDMA), subcarrier allocation, power spectrum, fading channels, outage capacity, fast frequency hopping, interference averaging. I.

### 1 Joint Allocation of Subcarriers and Transmit Powers in a Multiuser OFDM Cellular Network

"... Abstract — In the present paper, we consider the problem of joint bandwidth (subcarriers) and power allocation for the downlink of a multi-user multi-cell OFDM cellular network. This resource allocation problem is formulated as a power minimization problem, subject to meeting the target rates of all ..."

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Abstract — In the present paper, we consider the problem of joint bandwidth (subcarriers) and power allocation for the downlink of a multi-user multi-cell OFDM cellular network. This resource allocation problem is formulated as a power minimization problem, subject to meeting the target rates of all users in the network. We develop a distributed solution to find the globally optimal allocation which determines the subcarrier and power allocation dynamically. In addition, we investigate the impact of reducing the complexity by reducing the number of degrees of freedom available in the optimization. In particular, we consider a static bandwidth allocation scheme, and a static power allocation scheme. The numerical results show that the penalty on network performance due to the reduction in the available degrees of freedom is not significant. I.

### Dynamic Allocation of Subcarriers and Powers in a Multiuser OFDM Cellular Network

"... This paper considers a resource allocation problem in the downlink of a multiuser, multicell OFDM cellular network with frequency selective fading and imperfect channel state information. Each user has a given data rate requirement. The task is to determine power and subcarrier allocations for users ..."

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This paper considers a resource allocation problem in the downlink of a multiuser, multicell OFDM cellular network with frequency selective fading and imperfect channel state information. Each user has a given data rate requirement. The task is to determine power and subcarrier allocations for users to ensure that users ’ outage probabilities are low. A two-layer approach is used. The higher layer allocates powers based on the average gains of the links, with cells coupled via the mutual interference between them. To improve the performance in frequency selective fading, the lower layer allocates discrete subcarriers to the users in a way which takes into account statistical knowledge about the subcarriers.