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— We propose a new subcarrier allocation algorithm for Orthogonal Frequency Division Multiple Access (OFDMA) that gives fair allocation of capacity to multiple users with different channel and traffic characteristics. This is achieved by utilizing buffer state information and measured traffic statistics in addition to channel state feedback. Multiuser(More)
Wireless systems offer a unique mixture of connectivity, flexibility, and freedom. It is therefore not surprising that wireless technology is being embraced with increasing vigor. For real-time applications, user satisfaction is closely linked to quantities such as queue length, packet loss probability, and delay. System performance is therefore related to,(More)
—The rapid increase of content delivery over the Internet has led to the proliferation of content distribution networks (CDNs). Management of CDNs requires algorithms for request routing, content placement, and eviction in such a way that user delays are small. We abstract the system of frontend source nodes and backend caches of the CDN in the likeness of(More)
A wireless communication system in which multiple users cooperate to transmit information to a common destination is considered. The traffic generated by the users is subject to a stringent quality of service requirement, which is defined in terms of the asymptotic decay-rate of buffer occupancy. The performance of this communication system is analyzed, and(More)
Network coding has gained significant attention in recent years as a means to improve throughput, especially in multicast scenarios. These capacity gains are achieved by combining packets algebraically at various points in the network, thereby alleviating local congestion at the nodes. The benefits of network coding are greatest when the network is heavily(More)
Network coding has gained significant attention in recent years as a means to improve throughput, especially in multicast scenarios. These capacity gains are achieved by combining packets algebraically at various points in the network, thereby alleviating local congestion at the nodes. The benefits of network coding are greatest when the network is heavily(More)
This paper considers the relationship between code-rate selection and queueing performance for communication systems subject to time-varying channel conditions. While error-correcting codes offer protection against channel uncertainties, there exists a natural tradeoff between the enhanced protection of low-rate codes and the rate penalty imposed by(More)
This paper considers the queueing performance of a system that transmits coded data over a time-varying erasure channel. In our model, the queue length and channel state together form a Markov chain that depends on the system parameters. This gives a framework that allows a rigorous analysis of the queue as a function of the code rate. Most prior work in(More)
—The traditional formulation of the total value of information transfer is a multi-commodity flow problem. Each data source is seen as generating a commodity along a fixed route, and the objective is to maximize the total system throughput under some concept of fairness, subject to capacity constraints of the links used. This problem is well studied under(More)
This paper considers the relationship between code-rate selection and queueing performance for communication systems with time-varying parameters. While error-correcting codes offer protection against channel unreliability, there is a tradeoff between the enhanced protection of low-rate codes and the increased information transfer of high-rate codes. Hence,(More)