1,284 research outputs found
HySIM: A Hybrid Spectrum and Information Market for TV White Space Networks
We propose a hybrid spectrum and information market for a database-assisted
TV white space network, where the geo-location database serves as both a
spectrum market platform and an information market platform. We study the
inter- actions among the database operator, the spectrum licensee, and
unlicensed users systematically, using a three-layer hierarchical model. In
Layer I, the database and the licensee negotiate the commission fee that the
licensee pays for using the spectrum market platform. In Layer II, the database
and the licensee compete for selling information or channels to unlicensed
users. In Layer III, unlicensed users determine whether they should buy the
exclusive usage right of licensed channels from the licensee, or the
information regarding unlicensed channels from the database. Analyzing such a
three-layer model is challenging due to the co-existence of both positive and
negative network externalities in the information market. We characterize how
the network externalities affect the equilibrium behaviours of all parties
involved. Our numerical results show that the proposed hybrid market can
improve the network profit up to 87%, compared with a pure information market.
Meanwhile, the achieved network profit is very close to the coordinated
benchmark solution (the gap is less than 4% in our simulation).Comment: This manuscript serves as the online technical report of the article
published in IEEE International Conference on Computer Communications
(INFOCOM), 201
WAVEFORM DESIGN AND NETWORK SELECTION IN WIDEBAND SMALL CELL NETWORKS
The explosion in demand for wireless data traffic in recent years
has triggered rapid development and pervasive deployment of
wireless communication networks. To meet the exponentially
increasing demand, a promising solution is the concept of wideband
small cells, which is based on the idea of using broader frequency
bandwidth and employing more efficient radio frequency resource
reuse by dense deployment of wideband, short-range, low cost and
low power base-stations. Broader bandwidth provides substantial
degrees of freedom as well as challenges for system design due to
the abundant multipaths and thus interference in high speed
systems under large delay spread channels. Reducing the
transmission range and increasing the number of cells permit
better spatial reuse of spectrum. With the proliferation of
wideband small cells, the strategy of selection among multiple
networks has significant impacts to the performance of users and
to the load balance of the system. In this dissertation, we
address these problems with a focus on waveform design and network
selection.
In time-reversal communication systems, the time-reversal transmit
waveform can boost the signal-to-noise ratio at the receiver with
simple single-tap detection by utilizing channel reciprocity with
very low transmitter complexity. However, the large delay spread
gives rise to severe inter-symbol interference when the data rate
is high, and the achievable transmission rate is further degraded
in the multiuser downlink due to the inter-user interference. We
study the weighted sum rate optimization problem by means of
waveform design in the time-reversal multiuser downlink. We
propose a new power allocation algorithm, which is able to achieve
comparable sum rate performance to that of globally optimal power
allocation. Further, we study the joint waveform design and
interference pre-cancellation by exploiting the symbol information
to further improve the performance by utilizing the information of
previous symbols. In the proposed joint design, the causal
interference is subtracted using interference pre-cancellation and
the anti-causal interference can be further suppressed by waveform
design with more degrees of freedom.
The second part of this dissertation is concerned with the
wireless access network selection problem considering the negative
network externality, i.e, the influence of subsequent users'
decisions on an individual's throughput due to the limited
available resources. We formulate the wireless network selection
problem as a stochastic game with negative network externality and
show that finding the optimal decision rule can be modelled as a
multi-dimensional Markov decision process. A modified value
iteration algorithm is proposed to efficiently obtain the optimal
decision rule with a simple threshold structure, which enables us
to reduce the storage space of the strategy profile. We further
investigate the mechanism design problem with incentive
compatibility constraints, which enforce the networks to reveal
the truthful state information. We analyze a data set of wireless
LAN traces collected from campus networks, from which we observe
that the number of user arrivals is approximately Poisson
distributed; the session time and the waiting time to switch
network can be approximated by exponential distributions. Based on
the analysis, we formulate a wireless access network association
game with both arriving strategy and switching strategy and
validate the effectiveness of the proposed best response strategy
Network association strategies for an energy harvesting aided super-wifi network relying on measured solar activity
The super-WiFi network concept has been proposed for nationwide Internet access in the United States. However, the traditional mains power supply is not necessarily ubiquitous in this large-scale wireless network. Furthermore, the non-uniform geographic distribution of both the based-stations and the tele-traffic requires carefully considered user association. Relying on the rapidly developing energy harvesting techniques, we focus our attention on the sophisticated access point (AP) selection strategies conceived for the energy harvesting aided super-WiFi network. Explicitly, we propose a solar radiation model relying on the historical solar activity observation data provided by the University of Queensland, followed by a beneficial radiation parameter estimation method. Furthermore, we formulate both a Markov decision process (MDP) as well as a partially observable MDP (POMDP) for supporting the users’ decisions on beneficially selecting APs. Moreover, we conceive iterative algorithms for implementing our MDP and POMDP-based AP-selection, respectively. Finally, our performance results are benchmarked against a range of traditional decision-making algorithms
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