Applications of Repeated Games in Wireless Networks: A Survey

A repeated game is an effective tool to model interactions and conflicts for players aiming to achieve their objectives in a long-term basis. Contrary to static noncooperative games that model an interaction among players in only one period, in repeated games, interactions of players repeat for multiple periods; and thus the players become aware of other players' past behaviors and their future benefits, and will adapt their behavior accordingly. In wireless networks, conflicts among wireless nodes can lead to selfish behaviors, resulting in poor network performances and detrimental individual payoffs. In this paper, we survey the applications of repeated games in different wireless networks. The main goal is to demonstrate the use of repeated games to encourage wireless nodes to cooperate, thereby improving network performances and avoiding network disruption due to selfish behaviors. Furthermore, various problems in wireless networks and variations of repeated game models together with the corresponding solutions are discussed in this survey. Finally, we outline some open issues and future research directions.Comment: 32 pages, 15 figures, 5 tables, 168 reference

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical-layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical-layer message authentication is also introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201

A Comprehensive Survey of Potential Game Approaches to Wireless Networks

Potential games form a class of non-cooperative games where unilateral improvement dynamics are guaranteed to converge in many practical cases. The potential game approach has been applied to a wide range of wireless network problems, particularly to a variety of channel assignment problems. In this paper, the properties of potential games are introduced, and games in wireless networks that have been proven to be potential games are comprehensively discussed.Comment: 44 pages, 6 figures, to appear in IEICE Transactions on Communications, vol. E98-B, no. 9, Sept. 201

Women in the 2006 Olympic and Paralympic Winter Games: An Analysis of Participation, Leadership and Media Coverage

Increasing women's participation in the Olympic Movement as participants and leaders has been a slow and challenging process. While the number of "events" open to female athletes has increased steadily during the past 30 years, the actual number of female Olympic and Paralympic Winter Games participants and the number of opportunities to medal within those events has yet to equal the number of male participants or medals.The 2006 Paralympic Winter Games statistics are a good illustration of this discrepancy; while there are nearly an equal number of events open to female athletes, the total number of female Paralympic athletes was 99 of 474 or 20.9%. And, while women's participation has attempted to "catch up" with small increases in participation numbers, men's events and participation opportunities have continued to increase, thereby perpetuating and increasing the participation gap. For instance, there were 1,006 women (38.3%) and 1,627 men (61.7%) in the 2006 Olympic Winter Games compared to 886 women (36.9%) and 1,513 men (63.1%) in 2002. Interestingly, the same continued growth of men's sport and, as a result, the perpetuation of the gender gap has occurred in U.S. high school and college sport in the wake of Title IX's push for gender equity (BFHSA, 2006; NCAA, 2006). Some countries claim that the lack of women in their delegation is a result of lack of funding. The majority of these countries cite other reasons for the exclusion of women, such as social, cultural and religious differences (Good, 2002). However, the Olympic Charter specifically states that "Any form of discrimination with regard to a country or a person on grounds of race, religion, politics, gender or otherwise is incompatible with belonging to the Olympic Movement." (IOC, 2004). Thus, social, cultural and religious differences between men and women are not legitimate justifications for the lack of women in delegations. While the International Olympic Committee (IOC) has made significant efforts to play a leadership role in growing women's participation, it has had limited success in encouraging the International Paralympic Committee (IPC), the 203 National Olympic Committees (NOC) and international winter sport federations (IF) to commit to gender equality. Women are also significantly underrepresented in the IOC and on IF boards of directors, the international governance structures that determine whether women's sports are offered in Olympic, Paralympic and world championship competition. There are few women serving as members of National Olympic Committees (NOC), such as the United States Olympic Committee (USOC), that determine the size and composition of their respective national Olympic and Paralympic delegations and whether developmental programs are offered to support women's sports participation. And, like the situation in the United States, the underrepresentation of women is also reflected within each country's respective National Sports Governing Bodies (NGB) boards of directors (e.g., USA Hockey, U.S. Figure Skating, etc.) and at community leadership levels where grassroots participation opportunities ultimately determine the Olympic and Paralympic participation pipeline. Without strong leadership from governing boards at all levels, insufficiencies in financial support and programmatic infrastructure will continue and the number of female Olympic and Paralympic athletes will continue to lag behind men. Olympic status raises the visibility of both sports and athletes, opening new doors to media visibility, high earnings through prize money and endorsements, college scholarships and jobs and key influencer connections. More significantly, Olympic status also ignites the aspirations of millions of girls who are inspired to participate by the heroes they see. With an estimated audience of 2 billion, the Olympic Winter Games is the most widely viewed forum for winter sports (USA Weekend, 2006). Thus, it is important to regularly examine the state of women's participation as leaders and athletes in the Olympic and Paralympic Games. This report specifically examines such participation and leadership in the Olympic and Paralympic Winter Games from both an international and United States perspective