Uplink transmission in a new radio system operating on unlicensed spectrum
Systems, methods, and apparatuses disclosed herein can perform uplink (UL) transmission in new radio (NR) systems operating on an unlicensed spectrum. These systems, methods, and apparatuses can receive a downlink (DL) signal comprising information associated with listen before talk (LBT) type. These systems, methods, and apparatuses can perform the UL transmission based on the LBT type.
1 . A method of performing an uplink (UL) transmission in a wireless system operating on an unlicensed spectrum, the method comprising:
receiving, by a user equipment (UE), a downlink (DL) signal comprising information including a listen before talk (LBT) type jointly coded with an offset of a starting position of the UL transmission; and
performing, by the UE, the UL transmission based on the LBT type and the offset, wherein the UL transmission comprises a physical uplink shared channel (PUSCH) transmission and wherein a timing advance value for a UL slot associated with the PUSCH transmission is determined as:
(a) 0, if there is a physical random access channel (PRACH) resource configured in the UL slot; and
(b) an accumulated timing advance value, if there is no PRACH resource configured in the UL slot,
wherein one or more symbols in a slot before the UL slot are punctured for UL shared channel (UL-SCH) symbol mapping when no PRACH resource configured in the UL slot and wherein a number of the one or more symbols is determined based on the accumulated timing advance value.
2 . The method of claim 1 , wherein the LBT type comprises:
a category 1 (CAT-1) LBT type;
a category 2 (CAT-2) LBT type; or
a category 4 (CAT-4) LBT type.
3 . The method of claim 2 , wherein, when the LBT type is the CAT-1 LBT type, the performing comprises:
determining that the UL transmission is to begin no later than T microseconds (μs) after receiving the DL signal, wherein T is a number; and
performing the UL transmission at or before T μs.
4 . The method of claim 1 , wherein the DL signal is a downlink control information (DCI) and wherein the DCI comprises a 4-bit field used for indicating at least a subset of LBT types jointly coded with offsets.
5 . The method of claim 1 , wherein, when the LBT type is a category 2 (CAT-2) LBT type, the performing comprises:
determining that a duration of the UL transmission will exceed a threshold; and
performing the UL transmission at T microseconds (μs) after receiving the DL signal in response to determining that the duration of the UL transmission will exceed the threshold, wherein T is a number.
6 . The method of claim 5 , wherein the T μs is 16 μs or 25 μs and the threshold is 584 μs.
7 . The method of claim 1 , wherein a value of a single field in the DL signal indicates the LBT type jointly coded with the offset and the method further comprises determining the LBT type and the offset from the value of the single field.
8 . The method of claim 1 , wherein the information contains a jointly coded entry that is shared by a category 1 (CAT-1) LBT type and a category 2 (CAT-2) LBT type with duration of 16 μs and wherein a duration of the UL transmission is used to determine whether the LBT type indicated by the jointly coded entry is the CAT-1 LBT type or the CAT-2 LBT type with duration of 16 μs.
9 . A user equipment (UE), comprising:
radio front end circuitry configured to perform wireless communication over an unlicensed spectrum; and
processing circuitry configured to:
receive a downlink (DL) signal comprising information including a listen before talk (LBT) type jointly coded with an offset of a starting position of the an uplink (UL) transmission; and
perform the UL transmission based on the LBT type and the offset, wherein the UL transmission comprises a physical uplink shared channel (PUSCH) transmission and wherein a timing advance value for a UL slot associated with the PUSCH transmission is determined as:
(a) 0, if there is a physical random access channel (PRACH) resource configured in the UL slot; and
(b) an accumulated timing advance value, if there is no PRACH resource configured in the UL slot,
wherein the information contains a jointly coded entry that is shared by a category 1 (CAT-1) LBT type and a category 2 (CAT-2) LBT type with duration of 16 μs and wherein a duration of the UL transmission is used to determine whether the LBT type indicated by the jointly coded entry is the CAT-1 LBT type or the CAT-2 LBT type with duration of 16 μs.
10 . The UE of claim 9 , wherein the LBT type comprises:
the CAT-1 LBT type;
the CAT-2 LBT type; or
a category 4 (CAT-4) LBT type.
11 . The UE of claim 10 , wherein, when the LBT type is the CAT-1 LBT type, the processing circuitry is configured to:
determine that the UL transmission is to begin no later than T microseconds (μs) after receiving the DL signal, wherein T is a number; and
perform the UL transmission at or before T μs.
12 . The UE of claim 9 , wherein the DL signal is a downlink control information (DCI) and wherein the DCI comprises a 4-bit field used for indicating at least a subset of LBT types jointly coded with offsets.
13 . The UE of claim 9 , wherein, when the LBT type is the CAT-2 LBT type, the processing circuitry is configured to:
determine that a duration of the UL transmission will exceed a threshold; and
perform the UL transmission at T microseconds (μs) after receiving the DL signal in response to determining that the duration of the UL transmission will exceed the threshold, wherein T is a number.
14 . The UE of claim 9 , wherein a value of a single field in the DL signal indicates the LBT type jointly coded with the offset and the processing circuitry is further configured to determine the LBT type and the offset from the value of the single field.
15 . A system for performing uplink (UL) transmission in a wireless system operating on an unlicensed spectrum, the system comprising:
an access node configured to provide a downlink (DL) signal comprising information including a listen before talk (LBT) type jointly coded with an offset of a starting position of the UL transmission, wherein a value of a single field in the DL signal indicates the LBT type jointly coded with the offset; and
a user equipment (UE) configured to perform the UL transmission based on the LBT type and the offset, wherein the UE is configured to determine the LBT type and the offset from the value of the single field and wherein the UL transmission comprises a physical uplink shared channel (PUSCH) transmission and wherein a timing advance value for a UL slot associated with the PUSCH transmission is determined as:
(a) 0, if there is a physical random access channel (PRACH) resource configured in the UL slot; and
(b) an accumulated timing advance value, if there is no PRACH resource configured in the UL slot.
16 . The system of claim 15 , wherein the LBT type comprises:
a category 1 (CAT-1) LBT type;
a category 2 (CAT-2) LBT type; or
a category 4 (CAT-4) LBT type.
17 . The system of claim 16 , wherein, when the LBT type is the CAT-1 LBT type, the UE is configured to:
determine that the UL transmission is to begin no later than T microseconds (μs) after receiving the DL signal, wherein T is a number; and
perform the UL transmission at or before T μs.
18 . The system of claim 15 , wherein the DL signal is a downlink control information (DCI) and wherein the DCI comprises a 4-bit field used for indicating at least a subset of LBT types jointly coded with offsets.
19 . The system of claim 15 , wherein, when the LBT type is a category 2 (CAT-2) LBT type, the UE is configured to:
determine that a duration of the UL transmission will exceed a threshold; and
perform the UL transmission at T microseconds (μs) after receiving the DL signal in response to determining that the duration of the UL transmission will exceed the threshold, wherein T is a number.