616 research outputs found
Incentive Mechanisms for Hierarchical Spectrum Markets
In this paper, we study spectrum allocation mechanisms in hierarchical
multi-layer markets which are expected to proliferate in the near future based
on the current spectrum policy reform proposals. We consider a setting where a
state agency sells spectrum channels to Primary Operators (POs) who
subsequently resell them to Secondary Operators (SOs) through auctions. We show
that these hierarchical markets do not result in a socially efficient spectrum
allocation which is aimed by the agency, due to lack of coordination among the
entities in different layers and the inherently selfish revenue-maximizing
strategy of POs. In order to reconcile these opposing objectives, we propose an
incentive mechanism which aligns the strategy and the actions of the POs with
the objective of the agency, and thus leads to system performance improvement
in terms of social welfare. This pricing-based scheme constitutes a method for
hierarchical market regulation. A basic component of the proposed incentive
mechanism is a novel auction scheme which enables POs to allocate their
spectrum by balancing their derived revenue and the welfare of the SOs.Comment: 9 page
Spectrum Trading: An Abstracted Bibliography
This document contains a bibliographic list of major papers on spectrum
trading and their abstracts. The aim of the list is to offer researchers
entering this field a fast panorama of the current literature. The list is
continually updated on the webpage
\url{http://www.disp.uniroma2.it/users/naldi/Ricspt.html}. Omissions and papers
suggested for inclusion may be pointed out to the authors through e-mail
(\textit{[email protected]})
Applications of Game Theory and Microeconomics in Cognitive Radio and Femtocell Networks
Cognitive radio networks have recently been proposed as a promising approach to overcome the serious problem of spectrum scarcity. Other emerging concept for innovative spectrum utilization is femtocells. Femtocells are low-power and short-range wireless access points installed by the end-user in residential or enterprise environments. A common feature of cognitive radio and femtocells is their two-tier nature involving primary and secondary users (PUs, SUs). While this new paradigm enables innovative alternatives to conventional spectrum management and utilization, it also brings its own technical challenges.
A main challenge in cognitive radio is the design of efficient resource (spectrum) trading methods. Game and microeconomics theories provide tools for studying the strategic interactions through rationality and economic benefits between PUs and SUs for effective resource allocation. In this thesis, we investigate some efficient game theoretic and microeconomic approaches to address spectrum trading in cognitive networks. We propose two auction frameworks for shared and exclusive use models. In the first auction mechanism, we consider the shared used model in cognitive radio networks and design a spectrum trading method to maximize the total satisfaction of the SUs and revenue of the Wireless Service Provider (WSP). In the second auction mechanism, we investigate spectrum trading via auction approach for exclusive usage spectrum access model in cognitive radio networks. We consider a realistic valuation function and propose an efficient concurrent Vickrey-Clarke-Grove (VCG) mechanism for non-identical channel allocation among r-minded bidders in two different cases.
The realization of cognitive radio networks in practice requires the development of effective spectrum sensing methods. A fundamental question is how much time to allocate for sensing purposes. In the literature on cognitive radio, it is commonly assumed that fixed time durations are assigned for spectrum sensing and data transmission. It is however possible to improve the network performance by finding the best tradeoff between sensing time and throughput. In this thesis, we derive an expression for the total average throughput of the SUs over time-varying fading channels. Then we maximize the total average throughput in terms of sensing time and the number of SUs assigned to cooperatively sense each channel. For practical implementation, we propose a dynamical programming algorithm for joint optimization of sensing time and the number of cooperating SUs for sensing purpose. Simulation results demonstrate that significant improvement in the throughput of SUs is achieved in the case of joint optimization.
In the last part of the thesis, we further address the challenge of pricing in oligopoly market for open access femtocell networks. We propose dynamic pricing schemes based on microeconomic and game theoretic approaches such as market equilibrium, Bertrand game, multiple-leader-multiple-follower Stackelberg game. Based on our approaches, the per unit price of spectrum can be determined dynamically and mobile service providers can gain more revenue than fixed pricing scheme. Our proposed methods also provide residential customers more incentives and satisfaction to participate in open access model.1 yea
Research on efficiency and privacy issues in wireless communication
Wireless spectrum is a limited resource that must be used efficiently. It is also
a broadcast medium, hence, additional procedures are required to maintain communication
over the wireless spectrum private. In this thesis, we investigate three key
issues related to efficient use and privacy of wireless spectrum use. First, we propose
GAVEL, a truthful short-term auction mechanism that enables efficient use of the wireless
spectrum through the licensed shared access model. Second, we propose CPRecycle,
an improved Orthogonal Frequency Division Multiplexing (OFDM) receiver that
retrieves useful information from the cyclic prefix for interference mitigation thus improving
spectral efficiency. Third and finally, we propose WiFi Glass, an attack vector
on home WiFi networks to infer private information about home occupants.
First we consider, spectrum auctions. Existing short-term spectrum auctions do
not satisfy all the features required for a heterogeneous spectrum market. We discover
that this is due to the underlying auction format, the sealed bid auction. We propose
GAVEL, a truthful auction mechanism, that is based on the ascending bid auction
format, that avoids the pitfalls of existing auction mechanisms that are based on the
sealed bid auction format. Using extensive simulations we observe that GAVEL can
achieve better performance than existing mechanisms.
Second, we study the use of cyclic prefix in Orthogonal Frequency Division Multiplexing.
The cyclic prefix does contain useful information in the presence of interference.
We discover that while the signal of interest is redundant in the cyclic prefix,
the interference component varies significantly. We use this insight to design CPRecycle,
an improved OFDM receiver that is capable of using the information in the
cyclic prefix to mitigate various types of interference. It improves spectral efficiency
by decoding packets in the presence of interference. CPRecycle require changes to the
OFDM receiver and can be deployed in most networks today.
Finally, home WiFi networks are considered private when encryption is enabled
using WPA2. However, experiments conducted in real homes, show that the wireless
activity on the home network can be used to infer occupancy and activity states such as
sleeping and watching television. With this insight, we propose WiFi Glass, an attack
vector that can be used to infer occupancy and activity states (limited to three activity
classes), using only the passively sniffed WiFi signal from the home environment.
Evaluation with real data shows that in most of the cases, only about 15 minutes of
sniffed WiFi signal is required to infer private information, highlighting the need for
countermeasures
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