Method and system for direct mode communication within a talkgroup
First Claim
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.
1 Assignment
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Accused Products
Abstract
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.
91 Citations
16 Claims
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1. A method for receiving at a radio receiver a direct mode operation (DMO) transmission to a talkgroup, the method comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for transmitting from a radio transmitter a direct mode operation (DMO) transmission to a talkgroup, the method comprising:
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determining a required bandwidth for the DMO transmission in a defined radio frequency spectrum; identifying a range of contiguous resource blocks that are available for use in the defined radio frequency spectrum; transmitting a wake-up signal, wherein the wake-up signal comprises a talkgroup identifier; transmitting code sequences associated with the talkgroup identifier that identify both a center frequency and a transmission bandwidth corresponding to the range of contiguous resource blocks that are available for use in the defined radio frequency spectrum; and transmitting the DMO transmission at the center frequency and transmission bandwidth. - View Dependent Claims (8, 9)
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10. A radio receiver for receiving a direct mode operation (DMO) transmission to a talkgroup, the radio receiver comprising:
a receiver system including a protocol specific device to device (D2D) control system, wherein the receiver system and D2D control system are configured to; scan at the receiver system a defined radio frequency spectrum; receive at the receiver system in the defined radio frequency spectrum a wake-up signal; identify a talkgroup identifier in the wake-up signal, wherein the talkgroup identifier corresponds to a talkgroup being monitored by the receiver system; in response to identifying the talkgroup identifier, decode code sequences received at the receiver system and associated with the talkgroup identifier; identify in at least one of the code sequences both a center frequency and a transmission bandwidth of the DMO transmission; tune the receiver system 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. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A radio transmitter for transmitting a direct mode operation (DMO) transmission to a talkgroup, the radio transmitter comprising:
a transmitter system including a protocol specific device to device (D2D) control system, wherein the transmitter system and D2D control system are configured to; determine a required bandwidth for the DMO transmission in a defined radio frequency spectrum; identify a range of contiguous resource blocks that are available for use in the defined radio frequency spectrum; transmit a wake-up signal, wherein the wake-up signal comprises a talkgroup identifier; transmit code sequences associated with the talkgroup identifier that identify both a center frequency and a transmission bandwidth corresponding to the range of contiguous resource blocks that are available for use in the defined radio frequency spectrum; and transmit the DMO transmission at the center frequency and transmission bandwidth.
Specification