System and method for loop timing update of energy efficient physical layer devices using subset communication techniques
AssigneeBroadcom Corporation
InventorsPeiqing Wang, Linghsiao Wang, Mehmet Tazebay, Scott Powell
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Abstract
A system and method for loop timing update of energy efficient physical layer devices using subset communication techniques. During a quiet period during which a subset of communication channels are transitioned from an active mode to a low-power mode, circuitry in the active channel can be designed to track, on behalf of the inactive channels, the phase drift due to the frequency offset. This tracking of the frequency estimation error would reduce the time required to perform a timing update for the communication channels when transitioning back to the active mode.
Claims18
An energy efficient Ethernet method in a device that supports a plurality of channels, comprising:
- transitioning by said device from an active mode to a low power mode, said device including a plurality of receivers that are respectively associated with said plurality of channels, and a plurality of timing loops respectively supporting said plurality of channels, said low power mode having each receiver of a first subset of said plurality of channels in a low power state;
- tracking a frequency estimation error of a clock recovered from a signal received by a receiver that supports one of a second subset of said plurality of channels, the second subset of said plurality of channels remaining in an active state during said low power mode of said device;
- and
- applying said frequency estimation error to each timing loop that supports said first subset of said plurality of channels during a quiet period during which each receiver of said first subset of said plurality of channels is in said low power state, wherein said application of said frequency estimation error enables each timing loop that supports said first subset of said plurality of channels to track a phase drift during said quiet period.
An energy efficient Ethernet method for tracking a phase drift in a device, the device including a plurality of receivers that are respectively associated with a plurality of channels, comprising:
- after a first of said plurality of channels has transitioned to a low power state from an active state, tracking a frequency estimation error by a receiver associated with a second of said plurality of channels that remains active in said active state during a quiet period when said first of said plurality of channels remains in said low power state;
- during said quiet period, applying said frequency estimation error to a timing loop of said first of said plurality of channels;
- and
- transitioning said first of said plurality of channels from said low power state back to said active state using said timing loop to which said frequency estimation error has been applied.
An energy efficient Ethernet device that supports both an active mode and a low power mode, comprising:
- a plurality of receivers that are respectively associated with a plurality of channels, wherein during said low power mode each receiver of a first subset of said plurality of channels is in a low power state;
- a first timing recovery loop associated with a first receiver that supports one of a second subset of said plurality of channels that remains active during said low power mode of said energy efficient Ethernet device, said first timing recovery loop tracking a frequency estimation error;
- and
- a second timing recovery loop associated with a second receiver that supports one of said first subset of said plurality of channels, said second timing recovery loop receiving said frequency estimation error that is tracked by said first timing recovery loop, thereby enabling said second timing recovery loop to compensate for a phase drift while said second receiver is in said low power state.
Dependencies are inferred from the claim text.