A Power Control Algorithm for 3G WCDMA System (original) (raw)

Novel adaptive step power control algorithm for 3G WCDMA cellular system

… , 2009. ICCIT'09. 12th …, 2009

Power control is an essential radio resource management method in CDMA cellular communication systems, where co-channel and adjacent-channel interferences are the primary capacity limiting factors. Power control intends to control the transmission power levels in such a way that required quality of service for the users is guaranteed with lowest possible transmission powers. In this paper, a modulation of power control algorithm is proposed for the 3G WCDMA system. The algorithm is figured on a modification of the transmitted power update step size. Instead of the fixed value presently suggested, the step size is modified dynamically in order to obtain more adapted power variations as well as the step is also represented as a function of the difference between the target and estimated SIR of the MS to obtain more stability of the system. A general form of this algorithm is presented and it is then studied in a simple simulation. Performance of the algorithm was evaluated with the outage percentage, which is the percentage of the number of MS's whose received SIR falls below the fixed threshold. The focused requirement, which had been tried to achieve by this algorithm, is the stability, which was studied and represented through simulation.

A Comparative Investigation on WCDMA Power Control Mechanisms

2011

The main purpose of this research is to highlight the problems and advantages of both the power control mechanism and compare them accordingly. It has been investigated that open loop system is faster as compared to the close loop system as it has no long procedure or computations. It just have to compare the powers of MS (mobile station) and BS (base station) and increase / decrease the power. The present research mainly focuses on the comparison of WCDMA power control methods including, open and close loop methods, it further focus on channel transmission and signal-to-interference ratio (SIR). The channels used in controlling of power of WCDMA mobile networks are also investigated. Open loop power control has the limitations as it uses the same properties for both the directions of transmission as this is not the case every time practically or on the field. On the other hand close loop power control mechanism has a delay of 1/1.5 kHz (667 microseconds) but it is reliable because ...

Adaptive power control algorithm for 3G cellular CDMA networks

2004 IEEE 59th Vehicular Technology Conference. VTC 2004-Spring (IEEE Cat. No.04CH37514)

In this paper, we study adaptive power control algorithms for the Universal Mobile Telecommunications System (UMTS) and we propose an evolution for these algorithms. The proposed algorithm can be used in both link directions of the Frequency Division Duplex (FDD) mode and in the downlink of the Time Division Duplex (TDD) mode of UMTS, where the same closed-loop power control is used. Unlike the standardized closed-loop power control algorithm of UMTS, adaptive power control algorithms have a dynamic transmitted power update step. For these algorithms, power control steps depend on the instantaneous mobile command and the command history. Our proposed algorithm adds Some intelligence to mobiles and base stations in order to limit oscillations around the target signal-to-interference ratio (SIR). When the received S I R is close to the target SIR, the receiver sends alternative up and down commands. These alternatives commands are interpreted by the transmitter. In this case, the transmitter stabilizes its transmitted power. Simulations

An Adaptive Power Control Algorithm For 3G Cellular Networks

2018

Power control in WCDMA networks: A queue-based approach

Proceedings of the 16th IFAC World Congress, 2005, 2005

In modern cellular communication systems, power control plays a fundamental role for efficient resource utilization. In such systems, in fact, many users transmit over the same radio channel using the same frequency band and time slots so that the signal of an individual user becomes interference for the other users. Hence the transmission power levels need to be smartly manipulated so as to achieve an adequate quality of service for as many users as possible and, thus, an efficient network utilization. Conventional power control algorithms adopt the Signal-to-Interference-plus-Noise Ratio (SINR) as controlled variable and neglect the important effects of the manipulated control variables (transmission powers) and of the retransmission mechanism on the queueing dynamics. In this paper, we pursue a different queue-based approach which takes into account the queuing dynamics and adopts the queue size as controlled variable. In this framework, the power control problem is formulated as an optimal control problem with a criterion trading off high performance (low queue sizes) vs. low costs (low transmision powers). In particular, a novel queue-based power control algorithm with low on-line computational burden is proposed and its performance is evaluated via simulation experiments. The simulation results exhibit an improved behavior of the proposed queue-based algorithm compared to conventional SINR-based algorithms.

Simulation Analysis of Adaptive Power Control Method in TD-SCDMA System

2007 IEEE Systems and Information Engineering Design Symposium, 2007

In time-division synchronous code-division multiple access (TD-SCDMA) system, power control is one of the key technologies of radio resource management. It plays a significant role in guaranteeing the high quality communication. In this paper, we propose an adaptive power control algorithm, which is easier implemented than widely used algorithms, for uplink of the power control module through a simple and reliable way. Our method is based on the step size fixed power control algorithm and we use a shift register in the receiver to deposit power control bits, on which we depend to regulate the power-adjusting step size adaptively. First, we define that the bit information be 1 or 0, if the receiving power is smaller or bigger than the target power. When there is 1 or 0 alternately, it means the receiving power is approximate to the target power. When there is 1 or 0 continuously, the step size needs adjusting strongly, for the receiving power is much smaller or bigger. By simulating our algorithm and the step size fixed power control algorithm in the physical layer simulation platform of TD-SCDMA system, we can see the adaptive algorithm has a better performance than the step size fixed algorithm in decreasing the Bit Error Rate (BER) of information transmission. The simulation results also show that system performance may be affected by different number of users and Doppler shift and this adaptive algorithm is applicable to small Doppler shift with the same Signal Noise Raito (SNR) to the step size fixed algorithm.

A New Power Control Algorithm for Cellular CDMA Systems

2009

The conventional closed-loop power control in cellular code division multiple access systems can only achieve limited performance due to its inability to track channel variations quickly. In this paper, we present a new power control algorithm which is able to increase the speed of convergence to track the changes in radio channel efficiently. Simulation results show that it outperforms the conventional algorithms.

researchpaper Modified Variable Step Size Power Control Algorithm for CDMA Systems

Power control mechanism is an important issue for Code Division Multiple Access (CDMA) systems which helps in achieving higher capacity, combating against near far effect and provides high link performance. Unless a suitable power control mechanism is developed cellular systems cannot perform better. Power control allows to minimize the transmit power while keeping the system performance above the required value. In previous research [4], variable step size for closed loop power control system has been studied and results showed an increase in convergence speed and stability by properly choosing the step size. The new algorithm presented in this paper shows that it can perform better than variable step size power control algorithm and can obtain higher stability and convergence speed for step size δ at 0.1.

A New Adaptive Power Control Algorithm for UMTS

2006

The capacity of Wideband Code Division Multiple Access (WCDMA) technologies used in Universal Mobile Telecommunication System (UMTS) relies on efficient power control algorithms. The conventional UMTS power control algorithm is based on a fixed step size algorithm. The algorithm causes variations in received SIR when the radio channel is stable. Furthermore, it lacks abilities to cope with rapid variations in fast fading channels. In this paper, we first investigate the performance of current power control algorithms and then propose a new adaptive power control algorithm for UMTS. The proposed algorithm can mitigate received SIR variations when channel fading changes slowly. Moreover, it is capable of tracking rapid changes in fast fading channels, where conventional UMTS power control algorithms fail to handle.

Modified Variable Step Size Power Control Algorithm for CDMA Systems

2012

A Power Control Algorithm for 3G WCDMA System (original) (raw)

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