Downlink network synchronization mechanism for femtocell in cellular OFDM systems
First Claim
1. A method for downlink transmission synchronization in a cellular orthogonal frequency division multiplexing (OFDM) system, the method comprising:
- (a) scanning and receiving a plurality of reference signals transmitted from a plurality of neighboring macro base stations by a femto base station;
(b) determining a desired reference signal by selecting from the received plurality of reference signals during a predefined observation window, wherein the observation window length is smaller than half of a frame length but substantially larger than propagation delay among the plurality of neighboring macro base stations; and
(c) configuring downlink radio signal transmission of the femto base station based on the desired reference signal such that the femto base station is synchronized with the plurality of neighboring macro base stations.
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Abstract
A method of downlink synchronization for a femto base station in a cellular orthogonal frequency division multiplexing (OFDM) system is provided. The femto base station first scans one or more received reference signals transmitted from a plurality of neighboring macro base stations. The femto base station then determines a desired reference signal from the received one or more reference signals based on the scanning result. Finally, the femto base station configures its downlink radio signal transmission time based on the desired reference signal such that the femto base station is synchronized with the plurality of neighboring macro base stations.
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Citations
21 Claims
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1. A method for downlink transmission synchronization in a cellular orthogonal frequency division multiplexing (OFDM) system, the method comprising:
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(a) scanning and receiving a plurality of reference signals transmitted from a plurality of neighboring macro base stations by a femto base station; (b) determining a desired reference signal by selecting from the received plurality of reference signals during a predefined observation window, wherein the observation window length is smaller than half of a frame length but substantially larger than propagation delay among the plurality of neighboring macro base stations; and (c) configuring downlink radio signal transmission of the femto base station based on the desired reference signal such that the femto base station is synchronized with the plurality of neighboring macro base stations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A femto base station in a cellular orthogonal frequency division multiplexing (OFDM) system, the femto base station comprising:
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a radio frequency (RF) module that receives a plurality of reference signals transmitted by a plurality of neighboring macro base stations; a timing detector that detects a corresponding arrival time of each of the reference signals; a timing abstractor that determines a desired timing reference based on the detected arrival time of a desired reference signal determined by selecting from the plurality of reference signals during a predefined observation window, wherein the observation window length is smaller than an OFDM frame length but substantially larger than propagation delay among the plurality of neighboring macro base stations; and a timing configuration module that configures downlink transmission timing of the femto base station based on the desired timing reference such that the femto base station is synchronized with the plurality of neighboring macro base stations. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A femto base station in a cellular orthogonal frequency division multiplexing (OFDM) system, the femto base station comprising:
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a radio frequency module that receives a plurality of reference signals transmitted by a plurality of neighboring macro base stations; and means for detecting a corresponding arrival time of each of the plurality of reference signals and thereby determining a desired timing reference of a desired reference signal by selecting from the plurality of reference signals during a predefined observation window, wherein the observation window length is smaller than half of a frame length but substantially larger than propagation delay among the plurality of neighboring macro base stations, and wherein the femto base station configures downlink transmission timing based on the desired timing reference such that the femto base station is synchronized with the plurality of neighboring macro base stations. - View Dependent Claims (19, 20, 21)
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Specification