Citation Context

...ame theory literature by Topkis [15] in 1979. S-modular games are of particular interest since they have Nash equilibriums, and there exists an upper and a lower bound on Nash strategies of each user =-=[18]-=-. Furthermore, these equilibriums can be attained by using a greedy best response type algorithm ([15], [14]). Definition 4.1: Consider a game G = 〈M,S,C〉 with strategy spaces Si ⊂ R m for all i ∈ M a...

Citation Context

... ensuring that the distributedISBN 978-3-901882-58-6 c© 2014 IFIP coordination process will iteratively reach a stable state. In this paper, we prove that the model at hand is a sub-modular game (see =-=[15]-=-, [14]). Such games have always a Nash Equilibrium and it can be attained using a greedy best response type algorithm (called algorithm I in both references). The result of the devised coordination pr...

Citation Context

... at the profit cell-edge users. A Fair SINR strategy is sought for where power is distributed among users in a way to obtain the same Signal-to-Interference and Noise Ratio (SINR) at the receiver. In =-=[10]-=-, two power control algorithms are proposed to automatically create soft fractional frequency reuse (FFR) patterns in OFDMA based systems. The goal of the proposed algorithms is to adjust the transmit...

Citation Context

... power level on resource blocks that suffer of bad radio conditions (usually RB allocated for cell-edge users). Therefore, it is considered as a method for Inter-Cell Interference Coordination (ICIC) =-=[6]-=-. Downlink power allocation in LTE systems can vary from cell to cell and can be, in each cell, device specific. Several works have proposed and studied Power Control algorithms in OFDM systems. In [7...

Citation Context

...er the selection of a pool of RBs in any BS i as will be explained in the next section. Hence, xli,k 6= 0.0. We denote by Di,k,u the data rate achieved by user u on RB k in BS i given by what follows =-=[16]-=-: Di,k,u = W Eb/N0 · SINRi,k,u, where W is the bandwidth per RB. Given a target error probability, it is necessary that Eb/N0 ≥ γ, for some threshold γ which is user specific. The assumption of a cons...

Citation Context

...n some games, the sequence of strategies generated by best response dynamics converges to a NE, regardless of the players initial strategies. S-modular games are part of those games. To reach the NE, =-=[13]-=- proposes the following greedy best response algorithm built on an algorithm called algorithm I in [14], [15]: there are T infinite increasing sequences T it for t ∈ T and i = 1, ...,m. Player i uses ...

Citation Context

...s necessary that Eb/N0 ≥ γ, for some threshold γ which is user specific. The assumption of a constant Eb/N0 target is generally valid as long as the same type of modulation is used for all data rates =-=[17]-=-. In any BS i, the cell will be logically divided into NZ concentric discs of radii Rz , z = 1, ..., NZ , and the area between two adjacent circles of radii Rz−1 and Rz is called zone z, z = 1, ..., N...

Citation Context

...g: (Pk) : minimize C(xi,k) = ∑ i∈M ∑ z∈Nz ci,k,z (10a) xi,k = {0.1, 0.2, 0.35, 0.5, 0.6, 0.7, 0.85, 1.0}, ∀i ∈M. (10b) Pk are integer non-linear optimization problems that are typically hard to solve =-=[22]-=-. Therefore, we start by relaxing the integrality constraints on xi,k, i.e., we assume that 0 < xi,k ≤ 1 for all i ∈ M and k ∈ RB i z . After relaxing the integrality constraints, the obtained optimiz...

Citation Context

... users with bad channel quality, in particular cell-edge users, can suffer from high interference caused by neighboring cells. Proposing efficient ways to hinder inter-cell interference is paramount (=-=[2]-=-, [3], [4], [5]). In this work, we propose to reduce ICI through efficient Power Control. Power control does not only reduce the impact of interfering signals by lowering their power level (signals us...

Citation Context

...h bad channel quality, in particular cell-edge users, can suffer from high interference caused by neighboring cells. Proposing efficient ways to hinder inter-cell interference is paramount ([2], [3], =-=[4]-=-, [5]). In this work, we propose to reduce ICI through efficient Power Control. Power control does not only reduce the impact of interfering signals by lowering their power level (signals usually belo...

Citation Context

...ing that the distributedISBN 978-3-901882-58-6 c© 2014 IFIP coordination process will iteratively reach a stable state. In this paper, we prove that the model at hand is a sub-modular game (see [15], =-=[14]-=-). Such games have always a Nash Equilibrium and it can be attained using a greedy best response type algorithm (called algorithm I in both references). The result of the devised coordination process ...

Citation Context

...ased when the order of the modulation scheme decreases and vice versa). It permits using high order modulation schemes at low Signal to Noise Ratio values without degrading the system performance. In =-=[9]-=-, an Adaptive Power Control (APC) is proposed to reduce inter-cell interference as excessively high transmission power for center-cell users will degrade the performances of edge-cell users. Hence, po...

Citation Context

...s with bad channel quality, in particular cell-edge users, can suffer from high interference caused by neighboring cells. Proposing efficient ways to hinder inter-cell interference is paramount ([2], =-=[3]-=-, [4], [5]). In this work, we propose to reduce ICI through efficient Power Control. Power control does not only reduce the impact of interfering signals by lowering their power level (signals usually...

Citation Context

...6]. Downlink power allocation in LTE systems can vary from cell to cell and can be, in each cell, device specific. Several works have proposed and studied Power Control algorithms in OFDM systems. In =-=[7]-=-, authors put forward a distributed power control algorithm where each cell aims independently at minimizing its own power consumption under users rate constraints. Despite the absence of cooperation ...

Citation Context

...is semi-distributed as it relies on gradient information exchanged periodically by neighboring cells, whereas the second one is fully distributed relying on a non-trivial heuristic. The work in ([11],=-=[12]-=-) builds upon the work in [10]. The work in [11] extends the proposed algorithms for multi antenna OFDM systems with space division multiple access. The work in [12] differs mainly in the granularity ...

Citation Context

... channel quality, in particular cell-edge users, can suffer from high interference caused by neighboring cells. Proposing efficient ways to hinder inter-cell interference is paramount ([2], [3], [4], =-=[5]-=-). In this work, we propose to reduce ICI through efficient Power Control. Power control does not only reduce the impact of interfering signals by lowering their power level (signals usually belonging...

Citation Context

...urces in neighboring cells. Power control is done iteratively according to the proposed Bit Allocation Algorithm until the allocated power levels remain invariant after two consecutive iterations. In =-=[8]-=-, a hybrid algorithm combines adaptive modulation along with power control (i.e., the power level is increased when the order of the modulation scheme decreases and vice versa). It permits using high ...