Prach transmission power control with transmission index within pdcch order

A wireless transmit/receive unit (WTRU) comprising:

• a processor configured to:
• receive a physical downlink control channel (PDCCH) order for a random access channel (RACH) preamble transmission to a candidate cell, wherein the PDCCH order comprises a retransmission attempt index;
• and
• transmit a physical RACH (PRACH) retransmission using a transmit power that is based on the retransmission attempt index,
• wherein, when the retransmission attempt index indicates that the PRACH retransmission is a next PRACH transmission after a previous PRACH transmission attempt, the transmit power is increased by an offset of the transmit power for the previous PRACH transmission, and
• wherein, when the retransmission attempt index indicates that the PRACH transmission is not a next PRACH transmission after a previous PRACH transmission attempt, the transmit power is increased based on a last successfully received PDCCH order.

A method performed by wireless transmit/receive unit (WTRU), the method comprising:

• receiving a physical downlink control channel (PDCCH) order for a random access channel (RACH) preamble transmission to a candidate cell, wherein the PDCCH order comprises a retransmission attempt index;
• and
• transmitting a physical RACH (PRACH) retransmission using a transmit power that is based on the retransmission attempt index,
• wherein the method further comprises, when the retransmission attempt index indicates that the PRACH retransmission is a next PRACH transmission after a previous PRACH transmission attempt, increasing the transmit power by an offset of the transmit power for the previous PRACH transmission, or
• wherein the method further comprises, when the retransmission attempt index indicates that the PRACH transmission is not a next PRACH transmission after a previous PRACH transmission attempt, increasing the transmit power based on a last successfully received PDCCH order.