The universal mobile telecommunications system umts is a third generation mobile cellular system for networks based on the gsm standard. With algorithm 2, the inner loop power control is performed every five timeslots, that is, the frequency is lower to perform inner loop power control in algorithm 2. A power control algorithm for 3g wcdma system citeseerx. It specifies a complete network system and the technology described in it is popularly referred as freedom of mobile multimedia access foma. This completely revised and updated edition of the highly successful umts signaling provides a deep insight into all aspects of umts signalling. The control information is used for estimation purposes, and. Figures for the three main bands in use are given below. R99 downlink power control downlink power control means change of downlink power based on tpc command carried by uplink control channelul dpcch. The successful trial, deployment, operation and troubleshooting of 3g or umts infrastructures and applications is the.
The cdma technology used in umts relies on accurate power control techniques, not only for maximising the battery life of mobile terminals and maintaining signal quality, but also as an important means of optimising system capacity by controlling interference. The universal mobile telecommunications system umts, based on the gsm standards, is a mobile cellular system of third generation that is maintained by 3gpp 3rd generation partnership project. It aims to control the transmission power to ensure that the quality of service for each communication link is adequate and the interference in the system is minimised. Power control design issues making it desirable to include dynamic power control in a cellular system oreceived power must be sufficiently above the background noise for effective communication odesirable to minimize power in the transmitted signal from the mobile reduce cochannel interference, alleviate health concerns, save battery power.
Further, since the objective of the power control algorithm is to keep the ue power spectral density psd constant, total power transmitted by the ue scales with m. Cellular networks khoury college of computer sciences. Research open access an energy efficient semistatic. The future lines that are considered in the present, and other comment that already are in their last phase of development in the field of the mobile technology. Where things start to get interesting is with the power dynamics. Common pilot channel power control for umts cellular. Umts through wcdma can be summarized like a revolution of the air. Ontheonehandtheergchcaninstructtheueeithertoincrease or decrease the transmit power level by one step, or to keep the current transmit power level. This form of power control is used in wcdma to provide a coarse. In case of a softer handover, the downlink inner power control of the existing branch is directly applied to the new branch. In such systems, in fact, many users transmit over the same radio channel using the same frequency band and time slots so. Fredrik gunnarsson and fredrik gustafsson, control theory aspects of power control in umts, control engineering practice, volume 11, issue 10, pages 111125, october 2003. In umts, open loop power control is only used in tdd mode and for initial power setting in the frequency.
Innerloop power control is one of the essential radio resource management functions of wcdma systems. The results indicate that the first algorithm outperforms the second for the range of speeds considered. So algorithm 2 is applicable when the environment of mobile environment is quite favourable and the channel fades slowly or hardly fade. The notion of good performance can depend on context and may include optimizing metrics such as link data rate, network capacity, outage probability, geographic coverage and range, and life of the network and network. An energy efficient semistatic power control and link adaptation scheme in umts hsdpa yi huang, jie xu and ling qiu abstract high speed downlink packet access hsdpa has been successfully applied in commercial systems and improves user experience significantly. For those familiar with umts, the rf specifications cover familiar territory in regard to the requirements for open loop power control accuracy 10.
In the closed loop mode, the mobile station transmitter power is controlled by a signal from the base station. In this paper we present a soft handover algorithm for wide band cdma based eumts networks and the associated power control algorithm. The power level numbers vary according to the gsm band in use. In modern cellular communication systems, power control plays a fundamental role for efficient resource utilization. Wcdma is deployed in the 850 and 1900 of the existing frequency allocations and the new 3g band 17002100 should be available in the near future. High speed downlink packet access hsdpa has been successfully applied in commercial systems and improves user experience significantly. Moreover, it is capable of tracking rapid changes in fast fading channels, where conventional umts power control algorithms fail to handle.
Pdf power control with antenna array processing for umts. Power control provides protection against shadowing and fas t. Open loop power control vs closed loop power control. Developed and maintained by the 3gpp 3rd generation partnership project, umts is a component of the international telecommunications union imt2000 standard set and compares with the cdma2000 standard set for networks based on the competing. The mobile unit measurement is part of the open loop power control while the base station measurement is part of the closed loop power control. The importance of diversity is analyzed together with fast power. In such systems, in fact, many users transmit over the same radio channel using the same frequency band and time slots so that the. Optimal implementation of novel wcdma uplink outer loop. In this article, we address this issue by proposing a novel energy efficient semistatic power control and link adaptation scheme in hsdpa. Based on this estimate, the mobile unit adjusts the transmit power accordingly.
Jp4309117b2 hsscch transmission power control method in. For details of lte specific power control, you have to refer to ts 36. Important elements of the proposed algorithm are highlighted. Queuebased power control in umts systems luigi chisci, lorenzo mucchi and tommaso pecorella abstractin modern cellular communication systems, power control plays a fundamental role for ef.
Comprehesive coverage of umts 3g news, licensing, business developments, 3g wcdma telecommunication technology, multi media mobile phones and future communications. Objectives are higher data rates, lower latency on the user plane and control plane and a packetoptimized radio access technology. Uplink power control is also often more important in systems engineering of cellular networks 1. Several power control algorithms are standardized by 3gpp 1999 to be used in wcdma 3gpp, ts 25.
Umts long term evolution lte technology introduction. It is used for setting initial uplink and downlink transmission powers when a ue is accessing the network. This reduces resources and interference, hence, increases the systemwide. Outer loop power control sets the target sir for fast power control so that the desired quality is provided. Power control is the key path for launching the large scale cdma commercial network. Functionally the network elements are grouped into the radio access network. Power control in umts power control in umts can be widely classified as two types.
During sho, all cells in the active set receive the same tpc and acts accordingly. Two power control algorithms pcas that are currently specified by the 3rd generation partnership project 3gpp have been simulated in a vehicular environment. Within the functionality of interference management, there are sev. Selfoptimizing uplink outer loop power control for wcdma. Wcdma, outer loop power control, uplink received signal strength indicator ul rssi, maximum allowed signal to interference ratio sirmax, transmission.
Telefonaktiebolaget lm ericsson publ downlink power control in a cellular telecommunications network. Moreover, reducing the cpich power enables additional power saving on some of the other common control channels, of. Control theory aspects of power control in umts request pdf. Whereas power saving on cpich may not be a crucial aspect to the powercontrolled voice traffic, it is of great significance to data traffic. An energy efficient semistatic power control and link. The design contains a lot of flexibility to allow power control at different levels. The operation of power control is affected by the network architecture in wcdma, which is briefly illustrated in fig. Power control in wireless cellular networks princeton university. Amr codec in umts originally developed to be used in gsm by the etsi, the adaptive multirate amr speech codec ts 26. Currently, wcdma networks are deployed in umts band of around 2 ghz in europe and asia, including japan and america korea. The migration to umts is proposed as a simple way to reduce exposure to electromagnetic waves of the mobile telephony user.
Innerloop power control currently used in umts is a sirbased fixed stepsize power control fspc algorithm. Universal mobile telecommunications system umts terrestrial radio access utra frequency division duplex fdd downlink shared channel dsch power control in soft handover us6594499b1 en 20000925. Umts is a typical selfinterference system, thus the chief principle is that any potential surplus transmitted power for service must be controlled. The accuracies required for gsm power control are relatively stringent. Downlink power control parameters when downlink power control parms f1 is pressed, the following parameters are displayed in the downlink power control parameters middle menu. Usim umts subscriber identity module is a smart card that holds the subscriber identity, subscribed services, authentication and encryption keys utran node b equivalent to bts in gsmgprs performs the air interface processing channel coding, rate. To adjust the radiated power of mobile stations in a way that all received signals at the base station have the same sir for the same bit rate to reduce cochannel interference by concurrent users. Umts power control open loop power control is the ability of the ue transmitter to sets its output power to a specific value.
Power control with antenna array processing for umts. Universal mobile telecommunication system umts presented by m mateen shahid 2. This implies, ue transmit power will change quite considerably between different subframes in lte uplink. The preferred citation for this publication is, power control in wireless cellular. Power control and if you want to have some handson experience of these, i would recommand you to try some test items on 36. Wcdma occupies 5 mhz channels and has defined formats for elements such as synchronisation, power control and the like cdma technology. Using a variablerate transmission scheme also makes it possible to control the. Pdf in this paper, an evolution of the power control algorithm is proposed for the thirdgeneration wcdma system.
The proposed algorithm can mitigate received sir variations when channel fading changes slowly. Power control is essential in wcdma systems to provide satisfactory quality of service qos and to combat several problems. The relationship between fast power control and diversity. Pdf queuebased power control in umts systems tommaso. On the other hand the eagch demands an absolute value for the power level of the edch at which the ue is allowed to transmit. Lucent technologies proprietary what is umts umts stands for universal mobile telecommunications system umts is a part of the international telecommunications unions imt2000 vision of a global family of thirdgeneration 3g mobile communications systems umts will play a key.
But any one cell receives tpc erroneously that could impact the transmit power of. During this open loop control, it is assumed that both forward link from bs to ms and reverse link from ms to bs are correlated. Power control, broadly speaking, is the intelligent selection of transmitter power output in a communication system to achieve good performance within the system. In universal mobile telephony system umtsthe third generation mobile telephony system just being launchedpower control algorithms play an important role for efficient resource utilization. Power control in wireless cellular networks mung chiang electrical engineering department, princeton university prashanth hande electrical engineering department, princeton university. The openloop power control is employed at the beginning of a connection, and an uplink dedicated channel dch or common packet channel cpch, is not yet allocated. The chapter structure has been reworked for improved usability for readers, as well as including many new features and updates. Power control pc is an essential function of cellular.
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