Apparatus and method for synchronization in a multiple-carrier communication system by observing energy within a guard band
AssigneeAT&T Wireless Services, Inc.
InventorsJari M. Heinonen, Michael R. Hirano
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Abstract
A method, apparatus and system detects a loss of synchronization between a transmitter and a receiver in a multiple-carrier communication system such as an OFDM system. A guard band synchronization detector provides a synchronization indicator based on the energy detected within a guard band where a pilot tone is transmitted adjacent to the guard band. A timing error results in energy leakage into one or more guard bands. In one embodiment, a plurality of synchronization indicators are observed to determine whether a loss of synchronization between a transmitter and a receiver in the wireless system has occurred.
Claims22
A method of determining a loss of synchronization between a receiver and a transmitter, the method comprising:
- measuring an energy level of a pilot signal within a frequency guard band, the pilot signal transmitted adjacent to the frequency guard band;
- and
- detecting a loss of synchronization between a transmitter transmitting the pilot signal and a receiver in accordance with the energy level.
A method of detecting a loss of synchronization between a transmitter and a receiver comprising:
- measuring a first energy within a first guard band, wherein a first pilot signal is transmitted adjacent to the first guard band;
- measuring a second energy within a second guard band, wherein a second pilot signal is transmitted adjacent to the second guard band;
- and
- detecting a loss of synchronization between the transmitter and the receiver based on a ratio of the first energy to the second energy.
A method of detecting a loss of synchronization between a transmitter and a receiver in a multiple-carrier communication system, the method comprising:
- measuring a phase-to-frequency relationship for a plurality of pilot tones received at the receiver from the transmitter;
- measuring a first energy within a first guard band, wherein a first pilot signal is transmitted adjacent to the first guard band;
- measuring a second energy within a second guard band, wherein a second pilot signal is transmitted adjacent to the second guard band;
- and
- detecting a loss of synchronization between the transmitter and the receiver based on a ratio of the first energy to the second energy and the phase-to-frequency relationship.
A guard band energy synchronization detector comprising:
- an energy detector adapted to measure an energy level of a pilot signal within a frequency guard band, the pilot signal transmitted adjacent to the frequency guard band;
- and
- a controller adapted to determine a loss of synchronization between a transmitter transmitting the pilot signal and a receiver in accordance with the energy level.
Dependencies are inferred from the claim text.