Automatic timing adjustment for diverse routing of HFC systems

A system comprising:

• a first signal stream routing to only a first signal line loop for communication between a head-end and at least one communication unit;
• at least one redundant signal line coupled between the head-end and the at least one communication unit, the first signal stream routing through the at least one redundant signal line to form an alternate signal line loop when a fault of the first signal stream through the first signal line loop is detected;
• and
• the head-end adjusting a timing of the first signal stream according to a selected one of a number of predetermined delay parameters,
• wherein the predetermined delay parameters are defined as:
• Delay0=d1/u1=τd1+τu1
• Delay1=d1/u2=τd1+τu2
• Delay2=d2/u1=τd2+τu1
• Delay3=d2/u2=τd2+τu2
• where d1 is a length of a first downstream line, u1 is a length of a first upstream line, d2 is a length of a second downstream line, u2 is a length of a second upstream line, τd1, is a propagation delay for d1, Δd2 is a propagation delay for d2, τu1 is a propagation delay for u1, and τu2 is a propagation delay for u2.

A system comprising:

• a signal stream routing to only an optic signal line loop for communication between a head-end and at least one communication unit;
• at least one redundant optic signal line coupled between the head-end and the at least one communication unit, the signal stream routing through the at least one redundant optic signal line to form an alternate optic signal line loop when a fault of the signal stream through the optic signal line loop is detected;
• and
• the head-end adjusting a timing of the signal stream according to a selected one of a number of predetermined delay parameters, wherein the predetermined delay parameters are defined as:
• Delay0=d1/u1=τd1+τu1
• Delay1=d1/u2=τd1+τu2
• Delay2=d2/u1=τd2+τu1
• Delay3=d2/u2=τd2+τu2
• where d1 is a length of a first optic downstream line, u1 is a length of a first optic upstream line, d2 is a length of a second optic downstream line, u2 is a length of a second optic upstream line, τd1 is a propagation delay for d1, τd2 is a propagation delay for C2, τu1 is a propagation delay for u1, and τu2 is a propagation delay for u2.

A method comprising:

• determining that a signal stream has been routed through a redundant optic signal line when a fault of the signal stream through an optic signal line loop has been detected, the redundant optic signal line forming an alternate optic signal line loop, wherein the step of determining that the signal stream has been routed through a redundant optic signal line includes:
• receiving from at least one of a number of communication units coupled to the optic signal line loop a shortened uplink burst SUB;
• determining if the SUB from the at least one of the number of communication units aligns within a predetermined window of the signal stream;
• and
• concluding that the fault of the signal stream has occurred when the SUB does not completely align within the predetermined channel of the signal stream resulting in the signal stream routing through the redundant optic signal line;
• and
• selecting from multiple delay parameters at least one delay parameter corresponding to the alternate optic signal line loop to adjust a timing of the signal stream according to the at least one selected delay parameter.

A communication unit comprising:

• a transmitter sending a shortened uplink burst SUB to a head-end through a signal line loop;
• wherein the head-end routes a signal stream through a redundant signal line to form an alternate signal line loop when a fault is detected in the signal line loop, and adjusts a timing of the signal stream according to one of a number of predetermined delay parameters corresponding to the alternate signal line loop, and
• wherein the predetermined delay parameters are defined as:
• Delay0=d1/u1=τd1+τu1
• Delay1=d1/u2=τd1+τu2
• Delay2=d2/u1=τd2+τu1
• Delay3=d2/u2=τd2+τu2
• where d1 is a length of a first downstream line, u1 is a length of a first upstream line, d2 is a length of a second downstream line, u2 is a length of a second upstream line, τd1 is a propagation delay for d1, τd2 is a propagation delay for d2, τ6 u1 is a propagation delay for u1, and τu2 is a propagation delay for u2.