Showing papers by "Rapeepat Ratasuk published in 2008"

Method and apparatus for uplink power control in a communication system

Abstract: A communication system optimizes cell edge performance and spectral efficiency by a first step (404) of measuring, by the Node B, at least one system performance metric. A next step (406) includes sending, by the Node B, an indicator for the at least one system performance metric measurement. A next step (408) includes receiving the indicator for the at least one system performance metric measurement. A next step (410) includes determining an adaptive power control parameter based on the at least one system performance metric measured by the Node B and system performance metrics measured by at the least one other neighboring Node B. A next step (412) includes using the adaptive power control parameter to update an uplink transmit power level for at least one user equipment served by the Node B.

Method and apparatus for providing channel quality and precoding metric feedback in an orthogonal frequency division multiplexing communication system

Abstract: An Orthogonal Frequency Division Multiplexing communication system (100), wherein a frequency bandwidth is divided into one or more Resource Blocks Groups (RBGs) each having one or more Resource Blocks, provides for feedback of channel quality information and precoding metrics for a same at least one RBG of the one or more RBGs. More particularly, a user equipment (102) measures one or more channel quality parameters associated with at least one RBG of the one or more RBGs, determines channel quality information and a precoding metric for an RBG of the at least one RBG, and reports the channel quality information and a precoding metric determined for the RBG to a radio access network (110). In one embodiment of the invention, the RBG whose channel quality information and precoding metric are reported may be selected from the at least one RBG based on the measured channel quality parameters.

TDD design for UMTS Long-Term Evolution

Abstract: Long-term evolution (LTE) will provide substantial enhancements to UMTS 3G systems including improved system capacity and coverage, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. LTE supports both frequency division duplex (FDD) and time division duplex (TDD) modes to provide deployment flexibility in accordance with operatorpsilas preference and spectrum allocation. This paper presents an overview of LTE TDD design and highlights key differences with FDD. Design challenges unique to TDD are presented together with adopted technical solutions. Finally, simulation results are provided to demonstrate typical TDD system performance with data applications.

Uplink control signaling in a communication system

Abstract: A system and method for uplink control signaling in a communication system includes a step of transmitting ( 200 ) the uplink control signaling in a frequency resource of the communication system reserved for random access. In particular, this step ( 200 ) can include allowing ( 202 ) the Physical Uplink Control Channel (PUCCH) to coexist with the Physical Random Access CHannel (PRACH) and transmitting ( 204 ) only channels which do not require Acknowledged/Negative Acknowledged (ACK/NACK) transmission.

Multi-antenna system design for 3GPP LTE

Abstract: Standardization work is nearly complete on long term evolution (LTE) of the UMTS Terrestrial Radio Access and Radio Access Network which is aimed for commercial deployment in 2010. Goals for the evolved system include support for improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. To reach these goals, a new design for the air interface including state-of-art multi-antenna technology needs to be deployed. This paper provides a look at different multi-antenna schemes for LTE downlink and uplink. The paper also discusses various Node-B antenna configurations and summarizes the performance of different multi-antenna schemes under various scenarios.

On UMTS-LTE Physical Uplink Shared and Control Channels

Abstract: The performance of the uplink physical channel of the 3GPP LTE system is considered in this paper. Assuming a single user spatial division multiple access transmission scheme, where users' signals are transmitted over different subcarriers, a low complexity channel estimation technique is proposed for the physical uplink shared channel (PUSCH). The proposed channel estimation technique is shown to have significant gains in performance compared to other well known channel estimation techniques such as the maximum-likelihood (ML) and the inverse fast Fourier transform (IFFT) channel estimation methods [5]. Simulation results for different channel models and modulation and coding schemes (MCS) using incremental redundancy (IR) based hybrid automatic repeat request (HARQ) operation are also shown. Finally, a robust detection scheme is proposed for the physical uplink control channel (PUCCH) and simulation results are summarized.

Method and apparatus for implied resource assignment for uplink acknowledgment signalling

Abstract: A network node constructs ( 22 ) a downlink transmission using at least one group of resource elements. A remote unit receives ( 12 ) the downlink transmission and determines ( 13 ) a lowest index of the at least one group of resource elements. The remote unit then determines ( 14 ) an uplink resource, for use in uplink (UL) acknowledgment signaling, using the lowest index. The network node then receives ( 23, 24 ) the UL acknowledgment signaling that corresponds to the downlink transmission, the UL acknowledgment signaling having been transmitted using the uplink resource based on the lowest index. To determine the uplink resource, both the remote unit and the network node implicitly use the lowest index of the at least one group of resource elements that were used to construct the downlink transmission. Implicitly determining the uplink resource in this manner, serves to reduce overhead related to acknowledgment signaling.

Method for Allocating Non-Dedicated Resource as a Dedicated Resource

Abstract: A method of allocating resources and signatures of a random access resource (RACH) ( 200 ) that includes dedicated ( 202 ) and non-dedicated ( 204 ) resources or sub-resources is disclosed. The network device determines if the dedicated resource is available for allocation. If the dedicated resource is available, the network device allocates the dedicated resource. If the dedicated resource is blocked, the network device allocates one of the non-dedicated resources. A message can be sent that indicates that allocated non-dedicated resource is being allocated as a dedicated resource.

Allocating downlink feedback resources in wireless communication networks

Abstract: A wireless communication system (100) including a scheduling entity that transmits scheduling messages to first and second wireless terminals having different scheduling characteristics, wherein each scheduling message includes a reference signal cyclic shift indicator and a resource assignment. The assignment of the downlink feedback resource to the first wireless terminal is indicated by the reference signal cyclic shift indicator in the corresponding scheduling message, and the assignment of the downlink feedback resource to the second wireless terminal is indicated by a corresponding resource assignment.

Procédé et appareil pour fournir une rétroaction sur la qualité des canaux dans un système de communication avec multiplexage par répartition orthogonale de la fréquence

Abstract: L'invention concerne un systeme de communication avec multiplexage par repartition orthogonale de la frequence, dans lequel une bande passante (340) en frequence peut etre representee par des niveaux multiples (FIG. 3, n = 1, 2, 3) de groupes de blocs de ressources (RBG), chaque niveau de RBG comprenant une division de la bande passante en frequence donnant un nombre de RBG (301, 302, 306, 307-311, 331) different du nombre de RBG des autres niveaux de RBG, un equipement (102, 104) d'utilisateur mesurant (404) une qualite de canal associee a un ou plusieurs RBG d'un ou plusieurs niveaux de RBG des niveaux de RBG multiples, selectionnant (406) un RBG parmi les RBG mesures sur la base des qualites de canaux mesurees et rendant compte (408) a un reseau d'acces radio des informations de qualite de canal associees au RBG selectionne, ladite etape de compte rendu comportant les etapes consistant a attribuer un indice au RBG selectionne et a communiquer des informations de qualite de canal relatives au RBG indexe.