16 research outputs found
CSMA Local Area Networking under Dynamic Altruism
In this paper, we consider medium access control of local area networks
(LANs) under limited-information conditions as befits a distributed system.
Rather than assuming "by rule" conformance to a protocol designed to regulate
packet-flow rates (e.g., CSMA windowing), we begin with a non-cooperative game
framework and build a dynamic altruism term into the net utility. The effects
of altruism are analyzed at Nash equilibrium for both the ALOHA and CSMA
frameworks in the quasistationary (fictitious play) regime. We consider either
power or throughput based costs of networking, and the cases of identical or
heterogeneous (independent) users/players. In a numerical study we consider
diverse players, and we see that the effects of altruism for similar players
can be beneficial in the presence of significant congestion, but excessive
altruism may lead to underuse of the channel when demand is low
THE PRICE OF NON-COOPERATION IN RESERVATION-BASED BANDWIDTH SHARING PROTOCOLS
ABSTRACTIn reservation-based bandwidth sharing protocols, the base station relies on the stations’ requests to allocate time slots to them. Like most other protocols, reservation-based protocols were designed with the assumption that all stationsrespect the rules of the protocols. However, as mobile devices are becoming more intelligent andprogrammable, they can selfishly optimize their operations to obtain a larger share of commonbandwidth. Here, we study reservation-based bandwidth sharing protocols considering the existence of selfish stations through game-theoretic perspectives. We show that this game admits a Nash equilibrium. Then, we prove the inefficiency of the Nash equilibrium. Game-theoretical analysis shows that local optimization in the bandwidth sharing problem with conflicted interests does not lead to any global optimization.Keywords. Nash equilibrium, Repeated game, Reservation-based
Cognitive MAC Protocols Using Memory for Distributed Spectrum Sharing Under Limited Spectrum Sensing
The main challenges of cognitive radio include spectrum sensing at the
physical (PHY) layer to detect the activity of primary users and spectrum
sharing at the medium access control (MAC) layer to coordinate access among
coexisting secondary users. In this paper, we consider a cognitive radio
network in which a primary user shares a channel with secondary users that
cannot distinguish the signals of the primary user from those of a secondary
user. We propose a class of distributed cognitive MAC protocols to achieve
efficient spectrum sharing among the secondary users while protecting the
primary user from potential interference by the secondary users. By using a MAC
protocol with one-slot memory, we can obtain high channel utilization by the
secondary users while limiting interference to the primary user at a low level.
The results of this paper suggest the possibility of utilizing MAC design in
cognitive radio networks to overcome limitations in spectrum sensing at the PHY
layer as well as to achieve spectrum sharing at the MAC layer.Comment: 24 pages, 7 figure
Adaptive MAC Protocols Using Memory for Networks with Critical Traffic
We consider wireless communication networks where network users are subject
to critical events such as emergencies and crises. If a critical event occurs
to a user, the user needs to send critical traffic as early as possible.
However, most existing medium access control (MAC) protocols are not adequate
to meet the urgent need for data transmission by users with critical traffic.
In this paper, we devise a class of distributed MAC protocols that achieve
coordination using the finite-length memory of users containing their own
observations and traffic types. We formulate a protocol design problem and find
optimal protocols that solve the problem. We show that the proposed protocols
enable a user with critical traffic to transmit its critical traffic without
interruption from other users after a short delay while allowing users to share
the channel efficiently when there is no critical traffic. Moreover, the
proposed protocols require short memory and can be implemented without explicit
message passing.Comment: 24 pages, 7 figures, 1 tabl
Distributed Game Theoretic Optimization and Management of Multichannel ALOHA Networks
The problem of distributed rate maximization in multi-channel ALOHA networks
is considered. First, we study the problem of constrained distributed rate
maximization, where user rates are subject to total transmission probability
constraints. We propose a best-response algorithm, where each user updates its
strategy to increase its rate according to the channel state information and
the current channel utilization. We prove the convergence of the algorithm to a
Nash equilibrium in both homogeneous and heterogeneous networks using the
theory of potential games. The performance of the best-response dynamic is
analyzed and compared to a simple transmission scheme, where users transmit
over the channel with the highest collision-free utility. Then, we consider the
case where users are not restricted by transmission probability constraints.
Distributed rate maximization under uncertainty is considered to achieve both
efficiency and fairness among users. We propose a distributed scheme where
users adjust their transmission probability to maximize their rates according
to the current network state, while maintaining the desired load on the
channels. We show that our approach plays an important role in achieving the
Nash bargaining solution among users. Sequential and parallel algorithms are
proposed to achieve the target solution in a distributed manner. The
efficiencies of the algorithms are demonstrated through both theoretical and
simulation results.Comment: 34 pages, 6 figures, accepted for publication in the IEEE/ACM
Transactions on Networking, part of this work was presented at IEEE CAMSAP
201
Near-Optimal Deviation-Proof Medium Access Control Designs in Wireless Networks
Distributed medium access control (MAC) protocols are essential for the
proliferation of low cost, decentralized wireless local area networks (WLANs).
Most MAC protocols are designed with the presumption that nodes comply with
prescribed rules. However, selfish nodes have natural motives to manipulate
protocols in order to improve their own performance. This often degrades the
performance of other nodes as well as that of the overall system. In this work,
we propose a class of protocols that limit the performance gain which nodes can
obtain through selfish manipulation while incurring only a small efficiency
loss. The proposed protocols are based on the idea of a review strategy, with
which nodes collect signals about the actions of other nodes over a period of
time, use a statistical test to infer whether or not other nodes are following
the prescribed protocol, and trigger a punishment if a departure from the
protocol is perceived. We consider the cases of private and public signals and
provide analytical and numerical results to demonstrate the properties of the
proposed protocols.Comment: 14 double-column pages, submitted to ACM/IEEE Trans Networkin