Uplink asynchronous non-orthogonal multiple access
Systems, methods, and instrumentalities are disclosed for non-orthogonal multiple access (NOMA), frequency hopping, and power control. NOMA may be applied to asynchronous and/or grant-free transmissions. Transmissions from multiple WTRUs may be performed using the same resources, and may comprise information for correctly identifying and decoding the transmissions. The transmissions may comprise a built-in deterministic sequence to support timing acquisition at a receiver. The transmissions may be distinguished based on respective transmit power used for the transmissions. Such transmit power may be dynamically controlled by applying a randomly selected power offset. The power control may be performed autonomously by a WTRU.
1. A wireless transmit/receive unit (WTRU), comprising:
a processor configured to:
receive configuration information over a network, wherein the configuration information indicates a set of power offsets associated with uplink operation by the WTRU;
determine a transmission power associated with an uplink transmission, wherein the transmission power is determined based on at least a parameter received over the network;
adjust the transmission power, wherein the adjustment comprises applying a power offset to the transmission power based on a condition that the uplink transmission includes a non-orthogonal multiple access transmission, and wherein the power offset is randomly selected by the WTRU from the set of power offsets indicated by the configuration information; and
perform the non-orthogonal multiple access transmission using the adjusted transmission power.
2. The WTRU of claim 1 , wherein the set of power offsets is indicated as a value range.
3. The WTRU of claim 1 , wherein the processor is configured to apply the power offset to the transmission power based on a further condition that downlink control information (DCI) is received by the WTRU indicating that the power offset is to be applied.
4. The WTRU of claim 1 , wherein the uplink transmission comprises a grant-free transmission.
5. The WTRU of claim 1 , wherein the uplink transmission further comprises a second type of transmission and the processor is configured to transmit the second type of transmission using a transmission power that is different from the adjusted transmission power.
6. The WTRU of claim 5 , wherein the second type of transmission comprises an orthogonal multiple access transmission.
7. The WTRU of claim 5 , wherein the non-orthogonal multiple access transmission is transmitted using a first subset of subframes or slots associated with the uplink transmission and the second type of transmission is transmitted using a second subset of subframes or slots associated with the uplink transmission.
8. The WTRU of claim 5 , wherein the non-orthogonal multiple access transmission is transmitted using a first subset of symbols associated with the uplink transmission and the second type transmission is transmitted using a second subset of symbols associated with the uplink transmission.
9. The WTRU of claim 1 , wherein the parameter comprises a transmit power control (TPC) command.
10. A method implemented in a wireless transmit/receive unit (WTRU), the method comprising:
the WTRU receiving configuration information over a network, wherein the configuration information indicates a set of power offsets associated with uplink operation by the WTRU;
the WTRU determining a transmission power associated with an uplink transmission, wherein the transmission power is determined based on at least a parameter received over the network;
the WTRU adjusting the transmission power, wherein the adjustment comprises the WTRU applying a power offset to the transmission power based on a condition that the uplink transmission comprises a non-orthogonal multiple access transmission, and wherein the power offset is randomly selected by the WTRU from the set of power offsets indicated by the configuration information; and
the WTRU performing the non-orthogonal multiple access transmission using the adjusted transmission power.
11. The method of claim 10 , wherein the set of power offsets is indicated as a value range.
12. The method of claim 10 , wherein the power offset is applied to the transmission power based on a further condition that downlink control information (DCI) is received by the WTRU indicating that the power offset is to be applied.
13. The method of claim 10 , wherein the uplink transmission comprises a grant-free transmission.
14. The method of claim 10 , wherein the uplink transmission further comprises a second type of transmission and the method further comprises transmitting the second type of transmission using a transmission power that is different than the adjusted transmission power.
15. The method of claim 14 , wherein the second type of transmission comprises an orthogonal multiple access transmission.
16. The method of claim 14 , wherein the non-orthogonal multiple access transmission is transmitted using a first subset of subframes or slots associated with the uplink transmission and the second type of transmission is transmitted using a second subset of subframes or slots associated with the uplink transmission.
17. The method of claim 14 , wherein the non-orthogonal multiple access transmission is transmitted using a first subset of symbols associated with the uplink transmission and the second type of transmission is transmitted using a second subset of symbols associated with the uplink transmission.
18. The method of claim 10 , wherein the parameter comprises a transmit power control (TPC) command.