Resource Reduction Method for the LTE-Advanced Uplink ACK/NACK Signal and SR

Seigo NAKAO  Kenji TAKAGI  Masaru FUKUOKA  Daichi IMAMURA  Hidekazu MURATA  Koji YAMAMOTO  Susumu YOSHIDA  

IEICE TRANSACTIONS on Communications   Vol.E94-B    No.1    pp.364-367
Publication Date: 2011/01/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.364
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Terrestrial Wireless Communication/Broadcasting Technologies
LTE-Advanced,  space orthogonal resource transmit diversity,  phase rotation,  ACK/NACK signal,  scheduling request,  

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Advanced Evolved Universal Terrestrial Radio Access (Advanced E-UTRA), called LTE-Advanced, has been standardized in the 3rd Generation Partnership Project (3GPP) as a candidate for IMT-Advanced. LTE-Advanced supports spatial orthogonal-resource transmit diversity (SORTD) [1],[2] for ACK/NACK signals and scheduling requests (SRs), which are used to control downlink hybrid automatic repeat requests (HARQs) and manage uplink radio resources based on uplink data traffic, respectively. Both ACK/NACK signals and SRs are carried via a physical uplink control channel (PUCCH) [3], and a common PUCCH format is used for both ACK/NACK signals and SRs. If SORTD is used, the base station assigns mutually orthogonal resources to each antenna included in the user equipment (UE) for ACK/NACK signals and SRs; hence, the number of required resources increases with the number of transmitting antennas in the UE. In this paper, we study the resource reduction method for ACK/NACK signal and SR in case of SORTD using the concept of common resource. In addition, we investigate a phase rotation scheme for common resources to improve the SR detection performance.