3,663 research outputs found
Adaptive Multicell 3D Beamforming in Multi-Antenna Cellular Networks
We consider a cellular network with multi-antenna base stations (BSs) and
single-antenna users, multicell cooperation, imperfect channel state
information, and directional antennas each with a vertically adjustable beam.
We investigate the impact of the elevation angle of the BS antenna pattern,
denoted as tilt, on the performance of the considered network when employing
either a conventional single-cell transmission or a fully cooperative multicell
transmission. Using the results of this investigation, we propose a novel
hybrid multicell cooperation technique in which the intercell interference is
controlled via either cooperative beamforming in the horizontal plane or
coordinated beamfroming in the vertical plane of the wireless channel, denoted
as adaptive multicell 3D beamforming. The main idea is to divide the coverage
area into two disjoint vertical regions and adapt the multicell cooperation
strategy at the BSs when serving each region. A fair scheduler is used to share
the time-slots between the vertical regions. It is shown that the proposed
technique can achieve performance comparable to that of a fully cooperative
transmission but with a significantly lower complexity and signaling
requirements. To make the performance analysis computationally efficient,
analytical expressions for the user ergodic rates under different beamforming
strategies are also derived.Comment: Accepted for publication in IEEE Transaction on Vehicular Technolog
Non-cooperative Feedback Rate Control Game for Channel State Information in Wireless Networks
It has been well recognized that channel state information (CSI) feedback is
of great importance for dowlink transmissions of closed-loop wireless networks.
However, the existing work typically researched the CSI feedback problem for
each individual mobile station (MS), and thus, cannot efficiently model the
interactions among self-interested mobile users in the network level. To this
end, in this paper, we propose an alternative approach to investigate the CSI
feedback rate control problem in the analytical setting of a game theoretic
framework, in which a multiple-antenna base station (BS) communicates with a
number of co-channel MSs through linear precoder. Specifically, we first
present a non-cooperative feedback-rate control game (NFC), in which each MS
selects the feedback rate to maximize its performance in a distributed way. To
improve efficiency from a social optimum point of view, we then introduce
pricing, called the non-cooperative feedback-rate control game with price
(NFCP). The game utility is defined as the performance gain by CSI feedback
minus the price as a linear function of the CSI feedback rate. The existence of
the Nash equilibrium of such games is investigated, and two types of feedback
protocols (FDMA and CSMA) are studied. Simulation results show that by
adjusting the pricing factor, the distributed NFCP game results in close
optimal performance compared with that of the centralized scheme.Comment: 26 pages, 10 figures; IEEE Journal on Selected Areas in
Communications, special issue on Game Theory in Wireless Communications, 201
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