Panayotis Mertikopoulos

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A large deviations approach is introduced, which calculates the probability density and outage probability of the multiple-input multiple-output (MIMO) mutual information, and is valid for large antenna numbers <i>N</i> . In contrast to previous asymptotic methods that only focused on the distribution close to its most probable value, this methodology(More)
This work proposes a distributed power allocation scheme for maximizing energy efficiency in the uplink of orthogonal frequency-division multiple access (OFDMA)-based heterogeneous networks (HetNets) where a macro-tier is augmented with a mix of small cell access points – broadly varying in capabilities. The user equipment (UE) in the network are modeled as(More)
In this paper, we examine the fundamental trade-off between radiated power and achieved throughput in wireless multi-carrier, multiple-input and multiple-output (MIMO) systems that vary with time in an unpredictable fashion (e.g. due to changes in the wireless medium or the users’ QoS requirements). Contrary to the static/stationary channel regime, there is(More)
We investigate a class of reinforcement learning dynamics in which players adjust their strategies based on their actions’ cumulative payoffs over time – specifically, by playing mixed strategies that maximize their expected cumulative payoff minus a strongly convex, regularizing penalty term. In contrast to the class of penalty functions used to define(More)
We investigate the behavior of a large number of selfish users that are able to switch dynamically between multiple wireless access-points (possibly belonging to different standards) by introducing an iterated non-cooperative game. Users start out completely uneducated and naı̈ve but, by using a fixed set of strategies to process a broadcasted training(More)
In this paper, we investigate the allocation of network resources (such as Flow Table entries and bandwidth) in multitenant Software-Defined Networks (SDNs) that are managed by a FlowVisor. This resource allocation problem is modeled as an auction where the FlowVisor acts as the auctioneer and the network Controllers act as the bidders. The problem is(More)
We analyze the problem of distributed power allocation for orthogonal multiple access channels by considering a non-cooperative game whose strategy space corresponds to the users’ distribution of transmission power over the network’s channels. When the channels are static, we find that this game admits an exact potential function and this allows us to show(More)
We analyze the problem of finding the optimal signal covariance matrix for multiple-input multiple-output (MIMO) multiple access channels by using an approach based on &#x201D;ex-ponential learning&#x201D;, a novel optimization method which applies more generally to (quasi-)convex problems defined over sets of positive-definite matrices (with or without(More)
In this paper, we examine cognitive radio systems that evolve dynamically over time due to changing user and environmental conditions. To combine the advantages of orthogonal frequency division multiplexing (OFDM) and multipleinput, multiple-output (MIMO) technologies, we consider a MIMO–OFDM cognitive radio network where wireless users with multiple(More)