Ranging arrangement and method for TDMA communications
View Patent ↗An out-of-band ranging technique is automatically initiated at a customer premises equipment unit when the equipment is installed, when power is restored after a power failure or interruption, upon verification of the equipment, upon reconnection after a disconnection of the equipment or the like. To this end, an out-of-band tone is employed that is automatically transmitted when the customer premises equipment that transmits the TDMA signal is powered ON, or transmitted in response to a specific command generated locally or remotely. Specifically, when ranging is being effected the customer premises equipment generates and transmits the out-of-band ranging tone until a message is received from a remote terminal indicating that the transmission of the ranging tone be terminated. The loop delay being determined is the delay interval between transmission of the termination message and detection that transmission of the ranging tone has terminated. Then, a message is transmitted to the customer premises equipment that contains the ranging delay interval that is to be used in all future transmissions to the remote terminal.
1. Apparatus for use in a remote equipment unit at a prescribed remote location to generate a signal propagation ranging delay interval between the remote equipment unit and at least one local equipment unit located at a local location, the apparatus comprising:
a detector for detecting reception of an out-of-band ranging delay tone;
a transmitter responsive to detection of receiving said ranging delay tone for transmitting a termination message to said at least one local equipment unit to terminate transmission of said ranging delay tone, and for transmitting a message including a representation of a ranging delay interval to said at least one local equipment unit; and
a delay timer which is started upon transmission of said termination message and stopped upon said detector detecting that reception of said ranging delay tone has terminated, wherein an interval between said starting and stopping of said timer is said ranging delay interval.
2. The invention as defined in claim 1 wherein data to be transmitted from said at least one local equipment unit to said remote equipment unit is in a prescribed digital format including data bits organized into bytes in a repetitive frame.
3. The invention as defined in claim 2 wherein said representation of said delay interval includes a prescribed number of frames, a prescribed number of bytes and a prescribed number of bits.
4. The invention as defined in claim 2 wherein said transmitter transmits a message to said at least one local equipment unit assigning a time slot in which in-band data is to be transmitted from said at least one local equipment unit to said remote equipment unit.
5. The invention as defined in claim 4 further including a detector for determining whether an out-of-band ranging delay tone being received is aligned with said assigned time slot and for generating an indication of whether or not said received out-of-band ranging delay tone is aligned in said assigned time slot.
6. The invention as defined in claim 5 wherein said transmitter, in response to an indication that said out-of-band ranging delay tone is aligned with said assigned time slot, transmits a message to said at least one local equipment unit indicating that it should switch to an active data signal transmission state.
7. The invention as defined in claim 5 further including an adjustable ranging delay interval generator responsive to an indication that said out-of-band ranging delay tone is not aligned with said assigned time slot for adjusting said ranging delay interval so that said out-of-band ranging delay tone is aligned with said assigned time slot and wherein said transmitter transmits a message to said at least one local equipment unit including an adjusted ranging delay interval.
8. The invention as defined in claim 6 further including a detector for determining whether a data signal is being received from said at least one local equipment unit and whether it is aligned with said assigned time slot.
9. The invention as defined in claim 8 further including a detector for determining whether there is a loss of said data signal, and wherein said transmitter in response to an indication of said loss of data signal transmits a message indicating that said at least one local equipment unit is to switch to a verification state to verify that said data signal is aligned with said assigned time slot.
10. The invention as defined in claim 8 further including a detector for determining whether there is a substantial variation in alignment of said data signal with said assigned time slot, and wherein said transmitter, in response to an indication of said substantial variation of said data signal relative to said assigned time slot, transmits a message indicating that said at least one local equipment unit is to switch to a verification state to verify that said data signal is aligned with said assigned time slot.
11. The invention as defined in claim 8 further including a detector for determining whether there is a minor variation of alignment of said data signal with said assigned time slot, and wherein said transmitter in response to an indication of said minor variation of said data signal relative to said assigned time slot transmits a message including an adjusted ranging delay interval so that said data signal being transmitted from said at least one local equipment unit is aligned with said assigned time slot.
12. A method for use in a remote equipment unit at a prescribed remote location to generate a signal propagation ranging delay interval between the remote equipment unit and at least one local equipment unit located at a local location, the method comprising the steps of:
detecting reception of an out-of-band ranging delay tone;
in responsive to detection of receiving said ranging delay tone, transmitting a termination message to said at least one local equipment unit to terminate transmission of said ranging delay tone, and for transmitting a message including a representation of a ranging delay interval to said at least one local equipment unit; and
controlling a delay timer to be started upon transmission of said termination message and stopped upon detecting that reception of said ranging delay tone has terminated, wherein an interval between said starting and stopping of said timer is said ranging delay interval.
13. The method as defined in claim 12 wherein data to be transmitted from said at least one local equipment unit to said remote equipment unit is in a prescribed digital format including data bits organized into bytes in a repetitive frame.
14. The method as defined in claim 13 wherein said representation of said delay interval includes a prescribed number of frames, a prescribed number of bytes and a prescribed number of bits.
15. The method as defined in claim 13 wherein said step of transmitting transmits a message to said at least one local equipment unit assigning a time slot in which in-band data is to be transmitted from said at least one local equipment unit to said remote equipment unit.
16. The method as defined in claim 15 further including steps of determining whether an out-of-band ranging delay tone being received is aligned with said assigned time slot and generating an indication of whether or not said received out-of-band ranging delay tone is aligned in said assigned time slot.
17. The method as defined in claim 16 wherein said step of transmitting, in response to an indication that said out-of-band ranging delay tone is aligned with said assigned time slot, transmits a message to said at least one local equipment unit indicating that it should switch to an active data signal transmission state.
18. The method as defined in claim 16 further including the step of generating in response to an indication that said out-of-band ranging delay tone is not aligned with said assigned time slot, generates an adjusted ranging delay interval so that said out-of-band ranging delay tone is aligned with said assigned time slot, and wherein said step of transmitting transmits a message to said at least one local equipment unit including an adjusted ranging delay interval.
19. The method as defined in claim 17 further including a step of determining whether a data signal is being received from said at least one local equipment unit and whether it is aligned with said assigned time slot.