Transport format combination selection in a wireless transmit/receive unit
View Patent ↗A method and apparatus for selecting a TFC in a wireless transmit/receive unit (WTRU) is disclosed. The WTRU estimates a transmit power for each of a plurality of available transport format combinations (TFCs). A TFC is selected for an uplink dedicated channel and a TFC is selected for an enhanced uplink (EU) channel. The TFC for the dedicated channel is selected first and independently of the TFC selection of the EU channel. The TFC for the EU channel is selected within a remaining WTRU transmit power after the TFC selection for the dedicated channel.
1. A method implemented in a wireless transmit/receive unit (WTRU) for selecting a transport format combination (TFC), the WTRU being configured to process more than one channel for uplink transmission, the method comprising:
estimating a transmit power for each of a plurality of available TFCs;
selecting a TFC for an uplink dedicated channel (DCH) and a TFC for an enhanced uplink (EU) channel, wherein the TFC for the DCH is selected first, wherein the TFC for the DCH is selected based on a maximum allowed WTRU transmit power, wherein the TFC selection for the DCH is not affected by a power requirement for a TFC selection for the EU channel, and wherein the TFC for the EU channel is selected based on a WTRU transmit power remaining after the TFC selection for the DCH; and
transmitting data over the DCH in accordance with the TFC selected for DCH and transmitting data over the EU channel in accordance with the TFC selected for the EU channel, the WTRU to scale down a transmit power for the channels for uplink transmission if the maximum WTRU transmit power is exceeded as a result of selecting the TFC for the EU channel.
2. The method of claim 1 wherein one TFC is selected for each transmit time interval (TTI) of the DCH and one TFC is selected for each TTI of the EU channel.
3. The method of claim 1 wherein the remaining WTRU transmit power is estimated for every transmit time interval of either the EU channel or the DCH.
4. The method of claim 1 , wherein the WTRU operates in a excess power state to scale down a transmit power for the channels for uplink transmission if the maximum WTRU transmit power is exceeded as a result of selecting the TFC for the EU channel.
5. The method of claim 1 , wherein selecting the TFC for the DCH based on a maximum allowed WTRU transmit power comprises eliminating TFCs with a power requirement higher than the maximum allowed WTRU transmit power from being selected.
6. The method of claim 1 , wherein the maximum allowed WTRU transmit power is determined based, at least in part, on at least one of a selected data rate or quality of service.
7. A wireless transmit/receive unit (WTRU) for selecting transport format combinations (TFCs) for a plurality of uplink channels, the WTRU comprising:
a transmit power estimation unit configured to estimate a transmit power for each of a plurality of available TFCs;
a TFC selection unit configured to select a TFC for an uplink dedicated channel (DCH) and a TFC for an enhanced uplink (EU) channel, wherein the TFC for the DCH is selected first, wherein the TFC for the DCH is selected based on a maximum allowed WTRU transmit power, wherein the TFC selection for the DCH is not affected by a power requirement for a TFC selection for the EU channel, and wherein the TFC for the EU channel is selected based on a WTRU transmit power remaining after the TFC selection for the DCH; and
circuitry configured to transmit data over the DCH in accordance with the TFC selected for the DCH and to transmit data over the EU channel in accordance with the TFC selected for the EU channel, and to scale down a transmit power for the plurality of uplink channels if the maximum WTRU transmit power is exceeded as a result of the selection of the TFC for the EU channel.
8. The WTRU of claim 7 wherein one TFC is selected for each transmit time interval (TTI) of the DCH and one TFC is selected for each TTI of the EU channel.
9. The WTRU of claim 7 wherein the remaining WTRU transmit power is estimated for every transmit time interval of either the EU channel or the DCH.
10. The WTRU of claim 7 , wherein the circuitry is further configured for the WTRU to operate in a excess power state to scale down a transmit power for the channels for uplink transmission if the maximum WTRU transmit power is exceeded as a result of selecting the TFC for the EU channel.
11. The WTRU of claim 7 , wherein the TFC selection unit to select the TFC for the DCH based on a maximum allowed WTRU transmit power comprises the TFC selection unit to eliminate TFCs with a power requirement higher than the maximum allowed WTRU transmit power from being selected.
12. The WTRU of claim 7 , wherein the maximum allowed WTRU transmit power is determined based, at least in part, on at least one of a selected data rate or quality of service.