Supporting enhanced uplink transmission during soft handover
An enhanced uplink user equipment is in soft handover. A radio network controller selects a primary Node-B out of a plurality of Node-Bs supporting the soft handover. The radio network controller receiving successfully received enhanced uplink data packets from the plurality of Node-Bs. The radio network controller reordered the successfully received enhanced uplink data packets for in-sequence deliver. The primary Node-B sends specified scheduling information to the user equipment that the other Node-Bs does not transmit. At least the primary Node-B transmits acknowledgements and negative acknowledgements to the user equipment.
1. A method for enhanced uplink communication during soft handover implemented in a Node-B operating as a primary Node-B, comprising:
receiving quality information from a radio network controller (RNC);
using the quality information to determine specified scheduling information including the maximum transmission power of a wireless transmit/receive unit (WTRU);
transmitting to the WTRU the specified scheduling information, wherein the specified scheduling information is not transmitted to the WTRU by any non-primary Node-B;
receiving an enhanced uplink data packet from the WTRU in response to transmitting the specified scheduling information;
performing a cyclic redundancy check (CRC) on the enhanced uplink data packet;
transmitting an acknowledgement (ACK) or a negative acknowledgment (NACK) to the WTRU in response to the received enhanced uplink data packet wherein the transmission of either the ACK or NACK is based on the results of the CRC; and
further transmitting a successfully received enhanced uplink data packet to the RNC.
2. The method of claim 1 further comprising:
storing an unsuccessfully received enhanced uplink data packet in a buffer.
3. The method of claim 2 , further comprising:
soft combining the unsuccessfully received enhanced uplink data packet, stored in the buffer, with a retransmission of the enhanced uplink data packet for transmission to the RNC.