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Consejo Nacional de Ciencia y Tecnología, CONACYT: 83811
Generically Dependent Continuant
RDF description of Distributed power control algorithms for asynchronous CDMA systems in frequency-selective fading channels - http://orbis.uaslp.mx/vivo/individual/scopus2657
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CDMA wireless networks; Multipath fading; Multiuser detection; Power control; Uplink channels Adverse effect; Asynchronous transmission; CDMA system; CDMA wireless networks; Closed-loop; Control structure; Direct sequence; Distributed power control; Error function; Feedback scheme; Frequency-selective fading channels; Linear quadratic Gaussian; Multi-user receivers; Near-far effects; Near-far problem; Nonlinear coupling; Power control strategies; Propagation delays; Radio environment; Received power; Simulation result; Uplink channel; Uplink channels; Uplink power controls; Wireless channel; Algorithms; Base stations; Frequency selective fading; Multipath fading; Multiple access interference; Multiuser detection; Power control; Quality of service; Wireless networks; Code division multiple access
In Code Division Multiple Access (CDMA) radio environments, the maximum number of supportable users per cell is limited by multipath fading, shadowing, multiple access interference and near-far effects which cause fluctuations of the received power at the base station. In this context, power control and signal detection are essential to provide satisfactory Quality of Service (QoS) and to combat the near-far problem in CDMA systems. In this paper, we raised the uplink power control problem for a generalize asynchronous direct-sequence (DS) CDMA system that explicitly incorporate into the analysis: (1) the propagation delays in the network (generally neglected in the literature), (2) the adverse effect of multipath fading for wireless channels, and (3) the asynchronous transmissions in the uplink channels. This framework is used to propose a distributed power control strategy enhanced with linear multiuser receivers. It is shown that through a proper selection of an error function, the nonlinear coupling among active users is transformed into individual linear loops. A Linear-Quadratic-Gaussian (LQG) power control strategy is derived and compared with other approaches from the literature. Simulation results show that the uplink channel variations do not destroy the stability of these power control structures. However, delays in the closed-loop paths can severely affect the stability and performance of the resulting feedback schemes. It is also shown that the use of multiuser detection at the base station can bring significant improvements to the performance of power control. © 2010 Springer Science%2bBusiness Media, LLC.
In Code Division Multiple Access (CDMA) radio environments, the maximum number of supportable users per cell is limited by multipath fading, shadowing, multiple access interference and near-far effects which cause fluctuations of the received power at the base station. In this context, power control and signal detection are essential to provide satisfactory Quality of Service (QoS) and to combat the near-far problem in CDMA systems. In this paper, we raised the uplink power control problem for a generalize asynchronous direct-sequence (DS) CDMA system that explicitly incorporate into the analysis: (1) the propagation delays in the network (generally neglected in the literature), (2) the adverse effect of multipath fading for wireless channels, and (3) the asynchronous transmissions in the uplink channels. This framework is used to propose a distributed power control strategy enhanced with linear multiuser receivers. It is shown that through a proper selection of an error function, the nonlinear coupling among active users is transformed into individual linear loops. A Linear-Quadratic-Gaussian (LQG) power control strategy is derived and compared with other approaches from the literature. Simulation results show that the uplink channel variations do not destroy the stability of these power control structures. However, delays in the closed-loop paths can severely affect the stability and performance of the resulting feedback schemes. It is also shown that the use of multiuser detection at the base station can bring significant improvements to the performance of power control. © 2010 Springer Science Business Media, LLC.
Distributed power control algorithms for asynchronous CDMA systems in frequency-selective fading channels