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On the Performance of Distributed Power Control Algorithm over Wireless CDMA
Abstract
Most Power Control Algorithms require that the link gain between an access port and a mobile terminal should be known. This means a centralized measurement mechanism to track the movement of mobile terminals should be employed which in turn will result into heavy signaling between access ports and mobile terminals. Hence the practicability of designing such systems is not trivial. In this study, focus was made on Distributed Power Control (DPC) algorithm which avoids the centralized power control schemes. Performance of DPC Algorithm and its convergence was done through simulation. The results show what may be expected when DPC power control is implemented in a practical system.
In delay tolerant mobile networks, there are always no end-to-end paths due to sparse nodes and their irregular movement, so the forwarding of messages from source nodes to the destinations is a crucial task, which results in low probability of successful messages delivery and buffer occupancy for a long time. Routing in these networks is affected by some metrics, but the number of new connections especially is the crucial factor in delivering messages. Under this detection, we proposed every connection routing, which pay more attention to new connections between nodes but not the older ones. Further together with countdown timer and a fast buffer-released mechanism, every connection routing, are influenced by nodes’ speed, communication range and number, expiration time and simulation area. Buffer-release-enhanced weighted every connection routing may only increase processing time by the introducing of messages releasing time, but the benefit is lighter loaded buffers and higher efficiency of networks. The performance of buffer-release-enhanced weighted every connection routing is able to guarantees the validity of message delivery and improve the efficiency of the networks.
Efficiently sharing the spectrum resource is of paramount importance in wireless communication systems, in particular in Personal
Communications where large numbers of wireless subscribers are to be served. Spectrum resource sharing involves protecting
other users from excessive interference as well as making receivers more tolerant to this interference. Transmitter power
control techniques fall into the first category. In this paper we describe the power control problem, discuss its major factors,
objective criteria, measurable information and algorithm requirements. We attempt to put the problem in a general framework
and propose an evolving knowledge‐bank to share, study and compare between algorithms.
Eliminating the boundary effects is an important issue for a large-scale personal communication service (PCS) network simulation. A PCS network is often modeled by a network of hexagonal cells. The boundary may significantly bias the ouput statistics if the number of hexagonal cells is small in a PCS network simulation. On the other hand, if the simulation is to be completed within a reasonable time on the available computing resources, the number of cells in the simulation cannot be too large. To avoid the inaccuracy caused by the boundary effect for a PCS network simulation with limited computing resources, we propose wrapping the hexagonal mesh into a homogeneous graph (i.e., all nodes in the graph are topologically identical). We show that by using the wrapped hexagonal mesh, the inaccuracy of the output measures can be limited even though the number of cells in the simulation is small. We can thus obtain the same statistical accuracy while using significantly less computation power than required for a simulation without cell wrapping.
A power and spreading gain allocation strategy is considered for effectively providing data services for mobile users with different levels of priorities in a DS-CDMA system supporting real-time and non-real-time services. Specifically, the uplink in the DS-CDMA system is considered subject to a constraint on total power received at the base station caused by non-real-time data services. The constraint is imposed to meet QoS requirements of real-time services. The priority level of a data user is specified by the weighting factor assigned to the data throughput of the user. Our strategy implements a relative prioritization that affords a trade-off between spectral efficiency and strict prioritization.
Transmitter power control can be used to concurrently achieve
several key objectives in wireless networking, including minimizing
power consumption and prolonging the battery life of mobile nodes,
mitigating interference and increasing the network capacity, and
maintaining the required link QoS by adapting to node movements,
fluctuating interference, channel impairments, and so on. Moreover,
power control can be used as a vehicle for implementing on-line several
basic network operations, including admission control, channel selection
and switching, and handoff control. We consider issues associated with
the design of power-sensitive wireless network architectures, which
utilize power efficiently in establishing user communication at required
QoS levels. Our focus is mainly on the network layer and less on the
physical one. Besides reviewing some of the developments in power
control, we also formulate some general associated concepts which have
wide applicability to wireless network design. A synthesis of these
concepts into a framework for power-sensitive network architectures is
done, based on some key justifiable points. Various important relevant
issues are highlighted and discussed, as well as several directions for
further research in this area. Overall, a first step is taken toward the
design of power-sensitive network architectures for next-generation
wireless networks
This paper describes a centralized power control scheme for
cellular mobile radio systems. The power for the mobiles in the proposed
scheme is computed based on signal strength measurements. All the
mobiles using the same channel in this scheme will attain a common
carrier-to-interference ratio. The proposed scheme is analyzed and shown
to have an optimal solution
For wireless cellular communication systems, one seeks a simple
effective means of power control of signals associated with randomly
dispersed users that are reusing a single channel in different cells. By
effecting the lowest interference environment, in meeting a required
minimum signal-to-interference ratio of ρ per user, channel reuse is
maximized. Distributed procedures for doing this are of special
interest, since the centrally administered alternative requires added
infrastructure, latency, and network vulnerability. Successful
distributed powering entails guiding the evolution of the transmitted
power level of each of the signals, using only focal measurements, so
that eventually all users meet the ρ requirement. The local per
channel power measurements include that of the intended signal as well
as the undesired interference from other users (plus receiver noise).
For a certain simple distributed type of algorithm, whenever power
settings exist for which all users meet the ρ requirement, the
authors demonstrate exponentially fast convergence to these settings
Most cellular radio systems provide for the use of transmitter
power control to reduce cochannel interference for a given channel
allocation. Efficient interference management aims at achieving
acceptable carrier-to-interference ratios in all active communication
links in the system. Such schemes for the control of cochannel
interference are investigated. The effect of adjacent channel
interference is neglected. As a performance measure, the interference
(outage) probability is used, i.e., the probability that a randomly
chosen link is subject to excessive interference. In order to derive
upper performance bounds for transmitter power control schemes,
algorithms that are optimum in the sense that the interference
probability is minimized are suggested. Numerical results indicate that
these upper bounds exceed the performance of conventional systems by an
order of magnitude regarding interference suppression and by a factor of
3 to 4 regarding the system capacity. The structure of the optimum
algorithm shows that efficient power control and dynamic channel
assignment algorithms are closely related