RANDOM ACCESS FOR WIRELESS MULTIPLE-ACCESS COMMUNICATION SYSTEMS

摘要

Techniques for facilitating random access in wireless multiple-access communication systems. A random access channel (RACH) is defined to comprise a "fast" RACH (F-RACH) and a "slow" RACH (S-RACH). The F-RACH and S-RACH can efficiently support user terminals in different operating states and employ different designs. The F-RACH can be used to quickly access the system, and the S-RACH is more robust and can support user terminals in various operatin g states and conditions. The F-RACH may be used by user terminals that have registered with the system and can compensate for their round trip delays (RTDs) by properly advancing their transmit timing. The S-RACH may be used b y user terminals that may or may not have registered with the system, and may or may not be able to compensate for their RTDs. The user terminals may use the F- RACH or S-RACH, or both, to gain access to the system.