Mechanisms for indicating beam directions
A base station may transmit beam indication information to one or more user equipment (UE) devices. For each of a plurality of time units (e.g., symbols) in a time interval (e.g., spanning one or more slots), the beam indication information indicates a corresponding beam that the base station will use to transmit or receive. A UE device may have knowledge of the beam in which it currently resides, e.g., by performing power measurements during a beam scan procedure. Thus, the beam indication information enables the UE to perform transmissions and/or receptions (e.g., configured transmissions and/or receptions) during the appropriate time unit(s). The beam indication information may be dynamically transmitted as part of downlink control information. This transmission may omni-directional, wide beam, or narrow beam. Various schemes of encoding the beam indication information are contemplated.
1. A method, comprising:
receiving downlink control information (DCI) including beam indication information, wherein the beam indication information indicates:
one or more temporal units in a sequence of 14 symbols in a slot;
for each of the one or more temporal units, an indication of an uplink or downlink direction of data flow during that temporal interval; and
a first beam pattern from a predetermined list of multiple beam patterns, wherein each beam pattern of the predetermined list of beam patterns specifies a respective beam index for each respective temporal unit of the slot, wherein each beam pattern includes changing beams at least once during the slot and at least a subset of the beam patterns of the predetermined list of beam patterns includes using at least 3 different beams during the slot.
2. The method of claim 1 , wherein the downlink control information is a group common message, targeted for a group of user equipment (UE) devices.
3. The method of claim 1 , wherein the downlink control information is targeted only for a receiving user equipment (UE) device, wherein the beam indication information relates only to the beam in which the UE device resides.
4. The method of claim 1 , wherein said one or more temporal units are constrained to be among temporal units whose beam indications are not semi-statically configured.
5. The method of claim 1 , wherein the beam indication information applies only to a selected subset of a set of configured transfers, wherein the set of configured transfers includes one or more configured uplink transmissions and/or one or more configured downlink receptions, wherein the selected subset is determined by received configuration signaling, or predefined.
6. The method of claim 1 , wherein the beam indication information indicates a beam for a temporal unit by indicating a Transmission Configuration Indication (TCI) state or spatial relation for the temporal unit.
7. The method of claim 1 , further comprising:
determining whether a first beam used to transmit the DCI is the same as a second beam in which a user equipment (UE) device resides, wherein said determining includes:
recovering a beam index included in the DCI and comparing that beam index to a beam index of the second beam; or
attempting to descramble the DCI using a beam index of the second beam; or
attempting to descramble a CRC of the DCI using a beam index of the second beam.
8. The method of claim 1 , wherein the beam indication information is limited to information relating to two or more user equipment (UE)-specific beams contained within a beam used to transmit the DCI.
9. The method of claim 1 , wherein a first beam is used for transmission by a user equipment (UE) device, wherein a second beam is used for reception by the UE device.
10. The method of claim 1 , wherein the one or more temporal units are limited to temporal units corresponding to semi-statically configured transfers, wherein each of the semi-statically configured transfers is a semi-statically configured uplink transmission or a semi-statically configured downlink reception.
11. The method of claim 1 , wherein the beam indication information indicates:
a virtual beam pattern from a predetermined list of virtual beam patterns, wherein each of the virtual beam patterns specifies a virtual beam index for each of the temporal units of the temporal interval; and
a mapping of one or more virtual beam indices to one or more corresponding actual beam indices.
12. The method of claim 1 , further comprising:
performing a scheduled transmission or scheduled reception of data in one of the one or more temporal units without reference to a beam index indicated by the beam indication information.
13. The method of claim 1 , wherein the beam indication information is indicated with a granularity of XG symbols, wherein XG is equal to 2.
14. A method, comprising:
transmitting downlink control information (DCI) including beam indication information, wherein the beam indication information indicates:
one or more temporal units in a sequence of 14 symbols in a slot;
for each of the one or more temporal units, an indication of an uplink or downlink direction of data flow during that temporal interval; and
a first beam pattern from a predetermined list of multiple beam patterns, wherein each beam pattern of the predetermined list of beam patterns specifies a respective beam index for each respective temporal unit of the slot, wherein each beam pattern includes changing beams at least once during the slot and at least a subset of the beam patterns of the predetermined list of beam patterns using at least 3 different beams during the slot.
15. The method of claim 14 , wherein the beam indication information is indicated with a granularity of XG symbols, wherein XG is equal to 2.
16. The method of claim 14 , wherein the beam indication information indicates:
a virtual beam pattern from a predetermined list of virtual beam patterns, wherein each of the virtual beam patterns specifies a virtual beam index for each of the temporal units of the temporal interval; and
a mapping of one or more virtual beam indices to one or more corresponding actual beam indices.
17. A processor comprising:
a baseband processor; and
a memory management unit (MMU), the baseband processor and the MMU configured to perform operations comprising:
receiving downlink control information (DCI) including beam indication information, wherein the beam indication information indicates:
one or more temporal units in a sequence of 14 symbols in a slot;
for each of the one or more temporal units, an indication of an uplink or downlink direction of data flow during that temporal interval; and
a first beam pattern from a predetermined list of multiple beam patterns, wherein each beam pattern of the predetermined list of beam patterns specifies a respective beam index for each respective temporal unit of the slot, wherein each beam pattern includes changing beams at least once during the slot and at least a subset of the beam patterns of the predetermined list of beam patterns includes using at least 3 different beams during the slot.
18. The processor of claim 17 , wherein the downlink control information is a group common message, targeted for a group of user equipment (UE) devices.
19. The processor of claim 17 , wherein the beam indication information is indicated with a granularity of XG symbols, wherein XG is equal to 2.