Multipoint transmission in wireless communication
Embodiments contemplate wireless transmit/receive unit (WTRU) transmissions of different types of uplink channels and/or signals in a system deployment where multiple destination points may exist. Some embodiments contemplate that a WTRU may select the destination point of a transmission on a dynamic basis. In one or more systems where destination point selection from among multiple potential destination points may be possible for a WTRU transmission, some embodiments contemplate the determination of the handling of hybrid automatic repeat request (HARQ) retransmissions and for different power headroom reporting mechanisms. Embodiments also contemplate the reduction and/or inhibition of WTRU transmissions to destination points to which the WTRU may have lost connectivity.
1. A wireless transmit/receive unit (WTRU), comprising:
a receiver configured to receive downlink control information (DCI) and a configuration having at least two sets of power control parameters, each set of power control parameters having at least information of a desired received power and a partial path-loss compensation;
a processor configured, at least in part, to:
select a set of power control parameters, based on the DCI, from the at least two sets of power control parameters for an uplink transmission; and
determine a desired received power and a partial path-loss compensation associated with the uplink transmission based on the set of power control parameters and the DCI;
derive a path-loss estimate from a set of path-loss references based on the DCI; and
identify a power control adjustment state associated with the uplink transmission based on the DCI; and
a transmitter configured to transmit the uplink transmission using a power based on at least the desired received power, the partial path-loss compensation, the path-loss estimate, and the power control adjustment state.
2. The WTRU of claim 1 , wherein the DCI includes at least an index associated with the set of power control parameters.
3. The WTRU of claim 1 , wherein the uplink transmission is transmitted via a Physical Uplink Shared Channel (PUSCH).
4. A method performed by a wireless transmit/receive unit (WTRU), the method comprising:
receiving downlink control information (DCI) and a configuration having at least two sets of power control parameters, each set of power control parameters having at least information of a desired received power and a partial path-loss compensation;
selecting a set of power control parameters, based on the DCI, from the at least two sets of power control parameters for an uplink transmission;
determining a desired received power and a partial path-loss compensation associated with the uplink transmission, based on the set of power control parameters and the DCI;
maintaining a set of power control adjustment states;
selecting, from the set of power control adjustment states, a power control adjustment state associated with the uplink transmission based on the DCI; and
transmitting the uplink transmission using a power based on at least the desired received power, the partial path-loss compensation, and the power control adjustment state.
5. The method of claim 4 , wherein the DCI includes at least an index associated with the set of power control parameters.
6. The method of claim 4 , wherein the uplink transmission is transmitted via a Physical Uplink Shared Channel (PUSCH).
7. The WTRU of claim 1 , wherein the DCI is associated with one or more Transmit Power Control (TPC) commands.
8. The WTRU of claim 1 , wherein when identifying the power control adjustment state, the processor is configured to maintain a TPC command chain.
9. The WTRU of claim 1 , wherein the configuration is a Radio Resource Control (RRC) configuration, and the at least two sets of power control parameters are configured by the RRC configuration.
10. The WTRU of claim 1 , wherein the DCI includes a DCI format.
11. The WTRU of claim 1 , wherein the processor is configured to determine a maximum transmit power per carrier associated with the uplink transmission.
12. The method of claim 4 , wherein the DCI is associated with one or more TPC commands.
13. The method of claim 4 , wherein maintaining the set of power control adjustment states comprises maintaining a TPC command chain.
14. The method of claim 4 , wherein the configuration is a Radio Resource Control (RRC) configuration, and the at least two sets of power control parameters are configured by the RRC configuration.
15. The method of claim 4 , wherein the DCI includes a DCI format.
16. The method of claim 4 , further comprising determining a maximum transmit power per carrier associated with the uplink transmission.
17. The WTRU of claim 1 , wherein the processor is configured to:
maintain a set of power control adjustment states, and select the power control adjustment state from the set of power control adjustment states.
18. The method of claim 4 , further comprising:
deriving a path-loss estimate from a set of path-loss references based on the DCI, and wherein the power used for transmitting the uplink transmission is further based on the path-loss estimate.
19. A wireless transmit/receive unit (WTRU), comprising:
a receiver configured to receive downlink control information (DCI) and a configuration having at least two sets of power control parameters, each set of power control parameters having at least information of a desired received power and a partial path-loss compensation;
a processor configured, at least in part, to:
select a set of power control parameters, based on the DCI, from the at least two sets of power control parameters for an uplink transmission; and
determine a desired received power[and a partial path-loss compensation associated with the uplink transmission based on the set of power control parameters and the DCI;
maintain a set of power control adjustment states; and
select, from the set of power control adjustment states, a power control adjustment state associated with the uplink transmission based on the DCI; and
a transmitter configured to transmit the uplink transmission using a power based on at least the desired received power, the partial path-loss compensation, and the power control adjustment state.
20. The WTRU of claim 19 , wherein the processor is configured to:
derive a path-loss estimate from a set of path-loss references based on the DCI, and wherein the power used by the transmitter for transmitting the uplink transmission is further based on the path-loss estimate.