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EP-3918863-B1 - SYSTEMS AND METHODS FOR TRANSMISSION OF UPLINK CONTROL INFORMATION OVER MULTIPLE CARRIERS IN UNLICENSED SPECTRUM

EP3918863B1EP 3918863 B1EP3918863 B1EP 3918863B1EP-3918863-B1

Inventors

  • SALEM, Mohamed Adel

Dates

Publication Date
20260506
Application Date
20200225

Claims (11)

  1. A method performed by a user equipment, UE, the method comprising: receiving downlink control information, DCI, that indicates: an uplink resource partition in unlicensed spectrum for transmitting uplink control information, UCI, and a listen-before-talk, LBT, type to be used in association with the uplink resource partition (704), and a cyclic prefix, CP, extension to a first orthogonal frequency-division multiplexing, OFDM, symbol of an uplink transmission on the uplink resource partition and applied immediately before transmitting the first OFDM symbol of the uplink transmission on the uplink resource partition, the CP extension indicated in the DCI is used by the UE to create a gap of a specific duration from an end of a preceding downlink transmission to a beginning of the uplink transmission on the uplink resource partition; performing the LBT type indicated in the DCI (706); and transmitting the UCI on the uplink resource partition (710).
  2. The method of claim 1, wherein the UCI is hybrid automatic repeat request, HARQ, feedback corresponding to a downlink transport block, TB, that is scheduled by the DCI.
  3. The method of claim 1 or 2, wherein the specific duration of the gap is 25 µs or 16 µs, and wherein the UE performs LBT type 2.
  4. The method of any one of claims 1 to 3, wherein a duration of the CP extension is calculated by the UE based on a time alignment, TA, value and a subcarrier spacing, SCS.
  5. The method of claim 4, wherein the duration of the CP extension does not exceed one OFDM symbol duration.
  6. The method of any of claims 1 to 5, wherein the DCI indicates LBT type 1, and wherein performing the LBT type indicated in the DCI comprises performing LBT type 2 instead of LBT type 1 in response to receiving a slot format indication, SFI, indicating uplink resources within a base station's channel occupancy, and in response to determining that the indicated uplink resource partition is within the indicated uplink resources.
  7. The method of any of claims 1 to 6, wherein the DCI indicates that LBT type 1 is to be used in association with the uplink resource partition by the absence of an indication, in the DCI, that LBT type 2 is to be used in association with the uplink resource partition.
  8. The method of any of claims 1 to 7, wherein the uplink resource partition is a particular uplink resource partition, wherein the DCI indicates a plurality of uplink resource partitions for transmitting the UCI, the plurality of uplink resource partitions including the particular uplink resource partition, and wherein the method comprises: performing a respective LBT type for each of the plurality of uplink resource partitions, wherein the LBT type performed for the particular uplink resource partition is the LBT type indicated in the DCI.
  9. The method of claim 8, wherein each uplink resource partition of the plurality of uplink resource partitions is on a respective different component carrier in the unlicensed spectrum.
  10. The method of claim 8, wherein the LBT type performed for one of the plurality of uplink resource partitions is different from the LBT type performed for another one of the plurality of uplink resource partitions.
  11. A user equipment, UE (110) configured to perform the method of any one of claims 1 to 10.

Description

FIELD The present application relates to wireless communication in unlicensed spectrum, and more particularly to transmission of uplink control information (UCI) over multiple carriers in unlicensed spectrum. BACKGROUND In some wireless communication systems, user equipments (UEs) wirelessly communicate with a base station to send data to the base station and/or receive data from the base station. A wireless communication from a UE to a base station is referred to as an uplink communication. A wireless communication from a base station to a UE is referred to as a downlink communication. Resources are required to perform uplink and downlink communications. For example, a base station may wirelessly transmit data, such as a transport block (TB), to a UE in a downlink transmission at a particular frequency and over a particular duration of time. The frequency and time duration used are examples of resources. Wireless communication between a UE and a base station may occur on licensed spectrum, on unlicensed spectrum, or on both. Licensed spectrum refers to frequency bands that are licensed for use for wireless communications. A company licensing a particular frequency band has the right to wirelessly communicate using that frequency band in a given geographic area. Unlicensed spectrum refers to frequency bands that are not licensed for use for wireless communications, and that are free to use by anybody in compliance with the regional spectrum regulations. Therefore, the unlicensed spectrum is a shared spectrum. When wirelessly communicating on unlicensed spectrum, there is an expectation that there may be interference from other devices also transmitting on the same resources in the unlicensed spectrum. Therefore, a device operating on unlicensed spectrum, i.e., operating with shared spectrum access, may use a listen before talk (LBT) protocol in which the device first listens to the wireless channel to determine the availability of the channel before sending a transmission. LBT is thus a channel access procedure. It is desired to provide systems and methods that improve the reliability of wireless communication, and particularly uplink wireless communication, in unlicensed spectrum. Improving the reliability of wireless communication in unlicensed spectrum may better allow for mobile operators to at least partially offload their continuously increasing traffic load to the available unlicensed spectrum resources, e.g. using a unified/integrated carrier-type air interface. LG Electronics: "HARQ procedure for NR-U", 3GPP draft; R1-1902042 NR-U HARQ_FINAL, vol. RAN WG1, no, Athens, Greece; 20190225-20190301 16 February 2019 (2019-02-16), XP051599738 aims to duscuss on HARQ prcedure for NR-U operation in terms of data scheduling operation and HARQ-ACK feedback mechanism. Qualcomm Incorporated: "Enhancements to scheduling and HARQ operation for NR-U", 3GPP draft; R1-1902987 7.2.2.2.3 enhancements to scheduling and HARQ operation for NR-U, vol. RAN WG1, no, Athens, Greece; 20190225-20190301 16 February 2019 (2019-02-16), XP051600684 aims to duscuss enhancements to scheduling and HARQ operation for NR-U. NTT DOCOMO ET AL: "HARQ enhancement for NR-U", 3GPP draft; R1-1902791_ HARQ ENHANCEMENT FOR NR-U FINAL, vol. RAN WG1, no, Athens, Greece; 20190225-20190301 15 February 2019 (2019-02-15), XP051600486 aims to duscuss on potential HARQ enhancements. SUMMARY Systems and methods are disclosed that aim to facilitate wireless communication in unlicensed spectrum. In some embodiments, systems and method are disclosed that are directed to the transmission of uplink control information (UCI) in unlicensed spectrum. The UCI may be or include hybrid automatic repeat request (HARQ) feedback. The HARQ feedback may correspond to a downlink data transmission that was also sent on unlicensed spectrum. In some embodiments, multiple uplink resource partitions are allocated across different component carriers (CCs), and the UCI may possibly be sent on one or more of the allocated uplink resource partitions. An allocated uplink resource partition consists of at least an allocated uplink time-frequency resource partition, and possibly other resource parameters. A physical uplink control channel (PUCCH) allocated by a base station is an example of an allocated uplink resource partition. By allocating different uplink resource partitions across different CCs, the systems and methods of some embodiments may provide more reliable uplink transmission in unlicensed spectrum. In particular, if the UCI cannot be transmitted on an allocated uplink resource partition on one CC, e.g. because the wireless channel is occupied, then it may be possible to instead transmit the UCI on an uplink resource partition allocated on another CC. The invention is defined by the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will be described, by way of example only, with reference to the accompanying figures wherein: FIG. 1 is a network diagram of