| 摘要 |
A method and apparatus are provided for registering (unsynchronized) remote units with a multipoint communications system. An upstream multi-access channel (UMAC) is defined, over which non-registered remote units may transmit registration requests and related data. Non-registered remote units may transmit over the UMAC channel at any time independent of upstream transmissions from other remote units already registered with the network. To effect registration, the non-registered remote unit transmits a standardized asynchronous transmission sequence (ATS) signal over the UMAC channel. The ATS signal is "standardized" as it contains a predefined leading segment, the format for which is known to the head end unit. The ATS signal also contains a data segment that may be unique to the remote unit (e.g., it may uniquely identify the remote unit and/or request registration). The head end unit continuously monitors the UMAC channel and identifies an incoming ATS signal when it detects a predetermined sequence of amplitude and/or phase shifts in the incoming signal over the UMAC channel. The head end unit synchronizes the ATS signal therewith by identifying a reference point in the ATS signal based on known amplitude and/or phase shift(s) in the incoming signal. Once the ATS signal is synchronized, the head end unit obtains the data segment therefrom and registers the requesting remote unit. |
