Method and system for direct mode communication within a talkgroup

摘要

A method and system for direct mode operation (DMO) of a talkgroup enables device to device (D2D) DMO operation leveraged from a Land Mobile Radio (LMR) system. The method includes scanning at a radio receiver a defined radio frequency spectrum; receiving at the radio receiver in the defined radio frequency spectrum a wake-up signal; identifying a talkgroup identifier in the wake-up signal, wherein the talkgroup identifier corresponds to a talkgroup being monitored by the radio receiver; in response to identifying the talkgroup identifier, decoding code sequences included in the wake-up signal; identifying in at least one of the code sequences both a center frequency and a transmission bandwidth of the DMO transmission; and tuning the radio receiver to receive the DMO transmission at the center frequency and transmission bandwidth.

主权项

1. A method for receiving at a radio receiver a direct mode operation (DMO) transmission to a talkgroup, the method comprising:
scanning at the radio receiver a defined radio frequency spectrum; receiving at the radio receiver in the defined radio frequency spectrum a wake-up signal; identifying a talkgroup identifier in the wake-up signal, wherein the talkgroup identifier corresponds to a talkgroup being monitored by the radio receiver; in response to identifying the talkgroup identifier, decoding code sequences received at the radio receiver and associated with the talkgroup identifier; identifying in at least one of the code sequences both a center frequency and a transmission bandwidth of the DMO transmission; tuning the radio receiver to receive the DMO transmission at the center frequency and transmission bandwidth; and wherein the code sequences are Walsh code sequences and wherein decoding the code sequences comprises digital signal parallel processing of matched filters for Walsh sequence cross-correlation.