Signaling for wireless communications

摘要

A communication system, such as a wireless CDMA system, detects markers with fewer errors by having field units transmit the markers at different power levels (e.g., 9 dB for one marker and 11 dB for another marker). The difference in power levels of the markers allows the base station to identify the request markers using alternative criteria with a low probability of error, where the alternative criteria may include comparing the markers to respective energy level thresholds, monitoring occupancy of time slots, occupancy of mutually exclusive code channels, or combinations thereof. For example, in one particular embodiment, a request marker, which is generally a high priority marker, is transmitted with higher power, which improves the probability of detection and reduces the probability of false detection of the request marker.

主权项

1. A field unit comprising:
at least one processor configured to transmit a heartbeat signal having one of a plurality of formats; wherein the heartbeat signal is transmitted in response to the field unit not having an allocation of traffic data resources to maintain timing and power control and as an indication of presence within a network, wherein detection of the signal to maintain timing and power control occurs at a rate that is fast enough to track the slew of the timing of the code channel due to physical movement of multi-path structure change resulting from Doppler shifts in the channel and wherein the field unit provides the heartbeat signal using a first code in a reverse link and provides a heartbeat-with-request signal using a second code in the reverse link, the heartbeat and the heartbeat-with-request signals having a different power levels, giving the HB/RQST the higher power corresponding to a higher priority; on a condition that the field unit requires an allocation of traffic data resources, the at least one processor configured to transmit the heartbeat signal with a format of the plurality of formats associated with a request; wherein at least one of the formats is not associated with the request; in response to the request, the at least one processor configured to receive an allocation of traffic data resources and transmit reverse link data in response to the allocation in a time interval including at least one time slot; and the at least one processor configured to receive power commands and adjust the transmission power level of the heartbeat signal in response to the power commands.