Showing papers by "Rapeepat Ratasuk published in 2004"

Rapid channel quality based power control for high speed channels

Abstract: A method (400) and apparatus (501) provide for rapid power control based on a quality related value, e.g. channel quality indicator (CQI) value. A transmit power level can be derived from a CQI value received according to a time period, e.g. corresponding to 500 Hz. A first predicted value can be predicted based on the CQI value, at a first time within the time period and a power adjustment value can be determined based on the CQI value as well as the first predicted value at a rate that exceeds the rate of receiving the CQI values. Note that other predicted values for or corresponding to the CQI value can be predicted at other times within the time period and that power adjustment values can be determined through interpolation between predicted values for any time within the period.

Method and apparatus for dynamic power allocation to a multimedia broadcast/multicast service

Abstract: A communication system is provided that dynamically allocates power to a Multimedia Broadcast/Multicast Service (an MBMS service). In response to determining to establish a Point-to-Multipoint (PTM) communication channel to multiple user equipment (UEs), the communication service assigns the PTM communication channel to the MBMS service, determines a power requirement associated with each user equipment (UE) of the multiple UEs based on a handover quality measurement associated with the UE to produce multiple power requirements, and allocates a power level to the PTM communication channel based on the multiple power requirements. The communication system further dynamically adjusts the allocated power based on a handover quality measurement associated with a UE of the multiple UEs that is received during provision of the MBMS service.

Power allocation method for multicast services

Abstract: In a mobile telecommunication system (10), a number of user equipments (40-45) may receive multimedia broadcast multicast services. The method for power allocation and user assignment for MBMS services determines any number (K) of user equipments which may be served without complete cell area coverage (78). For more than K user equipments (40-45) requesting MBMS services, dedicated channels are assigned (84). For user equipments requesting MBMS service during a broadcast, such user equipment is assigned to the channel (broadcast or dedicated) with the lower power requirement, if power is available. If the user is assigned to the broadcast channel, and power is available, power of the broadcast channel is adjusted (108). Otherwise, the power of the broadcast channel is increased and no further power is indicated as being available (112).

Overview of enhanced uplink for 3GPP W-CDMA

Abstract: Enhanced uplink technology is currently being considered for standardization in 3GPP W-CDMA (Release-6) with the standard scheduled for completion in the 4/sup th/ quarter of 2004. Enhanced uplink technology under consideration includes advanced techniques such as adaptive modulation and coding (AMC), hybrid ARQ (HARQ), fast rate control or fast scheduling by the node-B (base station), higher peak rates (up to 2 Mbps) and a reduced transition latency between CELL_DCH, CELL_FACH and CELL_PCH states. These techniques reduce overall delay, and increase throughput significantly compared to release-99/4/5 3GPP W-CDMA. In this paper, the physical layer aspects of enhanced uplink for 3GPP W-CDMA FDD are discussed in detail with accompanying link and system simulation results. These results show that the sector and user throughput of the enhanced uplink (EU) can be improved by more than 50% compared to release-99/4/5 3GPP W-CDMA.

Apparatus and method for radio transmission in a cellular communication system

Abstract: A base station ( 101 ) of a cellular communication system ( 100 ) comprises a receiver ( 105 ) and a channel quality processor ( 111 ) which receive channel quality indications from a communication unit ( 103 ). The base station ( 101 ) further comprises a transmitter ( 107 ) for transmitting signals to the communication unit ( 103 ). A first power control processor ( 115 ) controls the transmit power in response to a first power control mode of operation and a second power control processor ( 117 ) controls the transmit power in response to the second power control mode of operation. A rate processor ( 113 ) determines a rate of change indication for the channel quality indications and a selector ( 119 ) selects between the first power control mode and the second power control mode in response to the rate of change indication. The power control mode of operation may be modified to suit the current channel variations of the communication channel. The invention may be applicable to an HSDPA service in a UMTS cellular communication system.

Method and apparatus for broadcast service classification and notification

Abstract: A system (100) and methods (400, 500) for alerting user equipment devices (116) in a wireless communication network (102) to broadcasts while limiting the amount of power that must be consumed in order to ascertain if the user equipment devices (116) have subscribed to the broadcasts are provided. A communication indicator (300) that is compatible with UMTS protocols and includes, in addition to paging indicators, one or more broadcast category indicator codes (304) is provided. Devices receiving the communication indicator (300) are able to ascertain based on the broadcast category indicator codes (304) whether there is a need to expend further power in determined whether they are subscribed to the broadcast.

Predicting link level performance for enhanced uplink

Abstract: The enhanced uplink feature is currently being standardized in release-6 of the 3GPP Universal Mobile Telecommunications System (UMTS). The goal of enhanced uplink is to increase the sector and user throughput on the uplink relative to release-5 UMTS through the use of advanced techniques such as adaptive modulation and coding, node-B controlled scheduling, and hybrid-ARQ. In order to effectively analyze system capacity of enhanced uplink, a suitable link error prediction methodology is needed. In this paper, two methods for predicting uplink performance, namely, short-term method and equivalent SNR method based on convex metric (ECM) are presented. The ECM method is simpler to implement since it requires only AWGN curves, whereas the short-term method requires curves for all radio configurations. Performance of these two methods is compared under various channel conditions and with hybrid ARQ enabled. In addition, the effect of chip and frame timing offset on E-DCH link prediction using ECM and the short-term approach is presented in this paper. Our results show that the ECM prediction method provides results that are very close to those obtained from actual simulations. Hence, the ECM method can be used to accurately model link level performance for the 3GPP enhanced uplink.

Adaptive rate matching assignment for multiplexed services in UMTS

Abstract: In UMTS W-CDMA systems, multiplexed services such as voice, data, and video may be offered simultaneously on one physical connection. Several issues such as the error rate requirement for each service. algorithmic complexity, hardware limitations, and performance of the overall system must be considered. In this paper, we investigate the radio resource allocation issues under Rayleigh fading conditions and present link-level performance for multiplexed services on the reverse-link of a UMTS W-CDMA system. Specifically, we present an adaptive algorithm for selecting rate matching parameters that satisfies the quality of service requirements for all simultaneous services. This selection is crucial since different services naturally have different underlying frame error rate (FER) requirements. From simulation results, it is seen that the adaptive algorithm can achieve the error rates required for multiplexed services of varying data rates and types (e.g. speech, video, and data services). In addition. it is observed that the proposed algorithm requires only a few adjustments for convergence.

Method of power control of pilot channel and corresponding communication device

Abstract: The present invention relates to methods of operation of a communication device and to corresponding communication devices. In particular the invention relates to a first method of operation of a communication device, wherein some pilot bits associated with data bits are transmitted with a power at least partly dependent on the data rate at which the data bits are transmitted. At the base station, power control is carried out only on pilot bits with constant power, whereas channel estimation is carried out on all pilot bits.