Distributed power allocation for D2D communications underlaying/overlaying OFDMA cellular networks

The implementation of device-to-device (D2D) underlaying or overlaying pre-existing cellular networks has received much attention due to the potential of enhancing the total cell throughput, reducing power consumption and increasing the instantaneous data rate. In this paper we propose a distributed power allocation scheme for D2D OFDMA communications and, in particular, we consider the two operating modes amenable to a distributed implementation: dedicated and reuse modes. The proposed schemes address the problem of maximizing the users' sum rate subject to power constraints, which is known to be nonconvex and, as such, extremely difficult to be solved exactly. We propose here a fresh approach to this well-known problem, capitalizing on the fact that the power allocation problem can be modeled as a potential game. Exploiting the potential games property of converging under better response dynamics, we propose two fully distributed iterative algorithms, one for each operation mode considered, where each user updates sequentially and autonomously its power allocation. Numerical results, computed for several different user scenarios, show that the proposed methods, which converge to one of the local maxima of the objective function, exhibit performance close to the maximum achievable optimum and outperform other schemes presented in the literature

Intergenerational Transfers and Household Structure. Why Do Most Italian Youths Live With Their Parents?

85 percent of Italian men aged 18-33 live with their parents. We argue that Italian parents like to live with their children and a rise in their income makes it possible for them to offer their children higher consumption in exchange for their presence at home. Children prefer to live on their own but are willing to exchange some independence for extra consumption. We formalize this intuition with a bargaining model between parents and children. We test the predictions of the model by estimating the effect of parental income on the probability that children live with their parents. The key econometric issue is the endogeneity of parental income. In order to identify the causal effect of parental income on children's living arrangements we use changes in parents' retirement age induced by the 1992 reform of the Italian social security as an instrument for parental income. By raising retirement age, this reform forced some fathers to remain in the labor market longer than the cohort immediately preceding them, therefore raising their income. Our instrumental variable estimates indicate that a rise in parents' income significantly raises the children's propensity to live at home: a $500 increase in annual parental income results in a 3 to 3.5 percentage point rise in the proportion of children living with their parents.Family structure, Living Arrangements, Two-Sample IV

Message passing resource allocation for the uplink of multicarrier systems

We propose a novel distributed resource allocation scheme for the up-link of a cellular multi-carrier system based on the message passing (MP) algorithm. In the proposed approach each transmitter iteratively sends and receives information messages to/from the base station with the goal of achieving an optimal resource allocation strategy. The exchanged messages are the solution of small distributed allocation problems. To reduce the computational load, the MP problems at the terminals follow a dynamic programming formulation. The advantage of the proposed scheme is that it distributes the computational effort among all the transmitters in the cell and it does not require the presence of a central controller that takes all the decisions. Numerical results show that the proposed approach is an excellent solution to the resource allocation problem for cellular multi-carrier systems.Comment: 6 pages, 4 figure

Resource Allocation for Power Minimization in the Downlink of THP-based Spatial Multiplexing MIMO-OFDMA Systems

In this work, we deal with resource allocation in the downlink of spatial multiplexing MIMO-OFDMA systems. In particular, we concentrate on the problem of jointly optimizing the transmit and receive processing matrices, the channel assignment and the power allocation with the objective of minimizing the total power consumption while satisfying different quality-of-service requirements. A layered architecture is used in which users are first partitioned in different groups on the basis of their channel quality and then channel assignment and transceiver design are sequentially addressed starting from the group of users with most adverse channel conditions. The multi-user interference among users belonging to different groups is removed at the base station using a Tomlinson-Harashima pre-coder operating at user level. Numerical results are used to highlight the effectiveness of the proposed solution and to make comparisons with existing alternatives.Comment: 12 pages, 6 figures, IEEE Trans. Veh. Techno

The pure B−LB-L model and future linear colliders: the Higgs sector

We summarise the phenomenology of the Higgs sector of the minimal $B-L$ extension of the Standard Model at an $e^+e^-$ Linear Collider. Within such a scenario, we show that (in comparison with the Large Hadron Collider) several novel production and decay channels involving the two physical Higgs states could experimentally be accessed at such a machine. In particular, we present the scope of the $Z'$ strahlung process for single and double Higgs production, the only suitable mechanism for accessing an almost decoupled heavy scalar state.Comment: This proceeding of the 2011 International Workshop on Future Linear Colliders (LCWS11) is published through the SLAC Electronic Conference Proceedings Archiv

Low Complexity WMMSE Power Allocation In NOMA-FD Systems

In this paper we study the problem of power and channel allocation with the objective of maximizing the system sum-rate for multicarrier non-orthogonal multiple access (NOMA) full duplex (FD) systems. Such an allocation problem is non-convex and, thus, with the goal of designing a low complexity solution, we propose a scheme based on the minimization of the weighted mean square error, which achieves performance reasonably close to the optimum and allows to clearly outperforms a conventional orthogonal multiple access approach. Numerical results assess the effectiveness of our algorithm.Comment: 5 pages conference paper, 3 figures. Submitted on ICASSP 202

Riassetto del trasporto pubblico di Firenze a seguito dell’entrata in servizio di nuove linee di tram (Upgrading of Florence public transport to incorporate new tramlines)

Nel 2018 due nuove linee di tram entreranno in servizio a Firenze, modificando la rete del trasporto pubblico nella zona nord della città. Lo studio esamina e confronta due soluzioni, una più innovativa e una più conservativa, progettate per migliorare il servizio di trasporto pubblico su gomma nell’area centro-settentrionale della Città Metropolitana di Firenze. Le soluzioni esaminate favoriscono l’integrazione tra le reti di autobus e tram, riducendo il flusso di traffico in aree strategiche d’interesse pubblico quali stazioni ferroviarie o settori ad alta domanda di traffico. Per ogni soluzione, l’articolo presenta lo studio della fattibilità tecnica e della relativa redditività finanziaria. Attraverso software di pianificazione e gestione del trasporto pubblico sono state valutate le caratteristiche tecniche e funzionali delle soluzioni proposte. I risultati dello studio evidenziano come la soluzione più innovativa sia quella migliore, sia dal punto di vista dell’efficienza del sistema, sia da quello economico, perché garantisce un miglioramento generale del servizio.In the last years, two new tramlines have been designed in the network of mass transit system in Florence. The planned lines will be in service in 2018 and they will serve the Northern part of the city. The work examines and compares two engineered solutions to improve the public transport service in the Northern and central areas of Florence: the former is more conservative, the latter more innovative. The alternatives facilitate the integration between the bus and tram network, reducing the traffic flow in strategical areas of public interest, such as railway stations or public offices areas. For each proposed scenario, the study consists of analysing the transport feasibility and financial viability. Specific transportation tools allowed evaluating the technical and functional characteristics of the proposed scenarios, while the economic impact is assessed using data provided by the consortium, which currently manages the public transport in the city. The results of this study suggest the more innovative solution as the best one, from both the transportation and economic points of view, because it guarantees an overall improvement of the service