Harq-ack signal transmission in response to detection of control channel type in case of multiple control channel types

Abstract

Methods and apparatus are described for a User Equipment (UE) to transmit and for a base station to receive a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) signal in a resource of a Physical Uplink Control CHannel (PUCCH). The HARQ-ACK signal is transmitted from the UE in response to a detection of a PDCCH transmitted from the base station and conveying a DCI format that, depending on the PDCCH type, can include a HARQ-ACK PUCCH Resource Offset (HPRO) information field. The UE and the NodeB determine the PUCCH resource depending on the PDCCH type and, if the DCI format includes the HPRO, also depending on a PDCCH transmission type.

Description

PRIORITY[0001]The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Applications Nos. 61 / 606,772, 61 / 675,518, 61 / 684,997, and 61 / 717,998, which were filed in the United States Patent and Trademark Office on Mar. 5, 2012, Jul. 25, 2012, Aug. 20, 2012, and Oct. 24, 2012, respectively, the disclosures of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates generally to wireless communication systems and, more particularly, to the transmission and reception of ACKnowledgements (ACK) signals.[0004]2. Description of the Art[0005]A communication system includes a DownLink (DL) that conveys transmission signals from transmission points, such as, for example, Base Stations (BSs), or NodeBs, to User Equipments (UEs). The communication system also includes an UpLink (UL) that conveys transmission signals from UEs to reception points, such as, for example BSs or NodeBs. A UE, which ...

AI Technical Summary

Benefits of technology

The present invention provides methods and apparatus for a user equipment (UE) to transmit and a base station to receive a hybrid automatic repeat request acknowledgement (HARQ-ACK) signal in a specific resource. This invention solves problems and limitations of previous systems and provides improved performance.

Problems solved by technology

This configuration limits PDCCH capacity and cannot achieve interference coordination in the frequency domain among PDCCH transmissions from different NodeBs.

A direct extension of the maximum DL control region size to more than MsymbDL=3 OFDM symbols is not possible at least due to the requirement to support legacy UEs, which cannot be aware of such an extension.

The use of spatial multiplexing for transmissions of EPDCCHs associated with PDSCHs to respective UEs results in PUCCH resource collision for respective HARQ-ACK signal transmissions under the conventional PUCCH resource determination.

Due to the limited number of ECCEs per PRB, such as 4 ECCEs per PRB, the PUCCH resource collision problem for transmitter antenna diversity exists regardless of the use of spatial multiplexing for EPDCCH transmissions.

The first two approaches increase PUCCH overhead compared to using only PDCCHs for scheduling PDSCHs even though an average number of such PDSCHs per subframe may not be larger than when both PDCCHs and EPDCCHs are used.

The first approach results in a larger increase in PUCCH overhead as, if a UE does not read the PCFICH, it may need to assume the largest number of CCEs for PDCCH transmissions.

The third approach may avoid increasing the PUCCH overhead but may place significant restrictions on the scheduler operation, which may not be feasible in practice.

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