QoS-constrained Energy Minimization in Multiuser Multicarrier Systems

On energy efficient cross-layer assisted resource allocation in multiuser multicarrier systems

“…Following the same approach proposed in [5] and adapted in [9], the Lagrange dual problem of (2) can be formulated and solved via Lagrange dual decomposition and the ellipsoid method. At convergence, the dual objective gives the best lower bound on the primal optimal value.…”

“…Table III are assumed, where the unit for b k is bit and the unit for τ k is ms. Two test scenarios are simulated under 1000 independent channel realizations, where P tot are set to 44 dBm and 50 dBm respectively. All the other simulation parameters remain the same as those taken in [9]. In Fig.…”

“…In Fig. 1(a) the histogram of the number of transmissions chosen for a user allowing for up to 5 transmissions is shown, which is obtained by simulations on the energy-minimizing scheme [9]. With ARQ protocol, allowing for only one transmission is almost always the best operation mode in terms of energy saving, whereas with HARQ, modes with more transmissions are also chosen yet transmitting with one trial is still the dominating mode.…”

“…Unlike in [9] where frequency band is the only resource the users share, under problem formulation (2) the users are still coupled by the transmit power constraint. Therefore, fixing subchannel assignment does not give us independent optimization problems for individual users.…”

“…The main contributions of this work are to investigate this trade-off thoroughly by using a cross-layer approach, as well as to mathematically formulate and solve the cross-layer assisted resource allocation problem in multicarrier systems based on it. We are motivated to study this problem through our previous works on energy and transmit power minimization algorithms [9] [10], which have been proposed based on ideas and methodologies from [3]- [5]. Some of these algorithms are adopted here to solve certain subproblems in the whole resource allocation procedure.…”