Validation of subscriber signals in a cellular radio network
First Claim
1. A method of validating an uplink signal received at a base station of a cellular radio communications network, comprising:
- defining a downlink time slot during which a base station assigned to a subscriber transmits a downlink signal for reception by the subscriber;
including in said downlink signal a defined reference signal at a certain time relative to the downlink time slot;
defining an uplink time slot during which the subscriber transmits an uplink signal for reception at a base station;
including in said uplink signal a defined reference signal at a certain time relative to the uplink time slot;
measuring a time offset between transmission from the base station of a reference signal associated with a downlink time slot and reception of a reference signal associated with an uplink time slot;
determining if said time offset is within a determined range; and
processing the uplink signal as valid only if said time offset is within said determined range.
3 Assignments
0 Petitions
Accused Products
Abstract
A relative time offset is measured between transmission of a downlink signal from a cellular radio network base station, and a reference signal (e.g., sync word) included in an uplink signal received at the base station from a network subscriber. If the measured time offset is within a determined range, the uplink signal is judged to originate from a subscriber which is validly assigned to the base station, and the base station will continue to track the valid uplink signal. If the relative time offset is outside the determined range, the uplink signal is judged invalid, e.g., to originate from an interfering co-channel subscriber assigned to a remote base station. The receiving base station will then inhibit tracking of the invalid uplink signal.
186 Citations
17 Claims
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1. A method of validating an uplink signal received at a base station of a cellular radio communications network, comprising:
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defining a downlink time slot during which a base station assigned to a subscriber transmits a downlink signal for reception by the subscriber; including in said downlink signal a defined reference signal at a certain time relative to the downlink time slot; defining an uplink time slot during which the subscriber transmits an uplink signal for reception at a base station; including in said uplink signal a defined reference signal at a certain time relative to the uplink time slot; measuring a time offset between transmission from the base station of a reference signal associated with a downlink time slot and reception of a reference signal associated with an uplink time slot; determining if said time offset is within a determined range; and processing the uplink signal as valid only if said time offset is within said determined range. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for validating an uplink signal received at a base station of a cellular radio communications network, comprising:
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first transmitter means at a given base station for transmitting a downlink signal from the base station for reception by a network subscriber; means associated with said first transmitter means for defining a downlink time slot during which the downlink signal is transmitted, and means for including in said downlink signal a reference signal at a certain time relative to the downlink time slot; second transmitter means associated with a network subscriber, for transmitting an uplink signal for reception at a network base station; means associated with the second transmitter means for defining an uplink time slot during which an uplink signal is transmitted, and means for including a reference signal in said uplink signal at a certain time relative to the uplink time slot; means at said given base station for measuring a time offset between transmission of the reference signal associated with a downlink time slot, and reception of a reference signal associated with an uplink time slot; means for determining if said time offset is within a determined range; and means for processing the uplink signal as valid only if said time offset is within said determined range. - View Dependent Claims (8, 9)
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10. A method of tracking an uplink signal received at a base station of a radio communications network, comprising:
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defining a downlink time slot during which a network base station transmits a downlink signal for reception by a network subscriber validly assigned to said base station; defining an uplink time slot during which said subscriber transmits an uplink signal for reception at the base station; including in said uplink signal a reference signal at a certain time with respect to said uplink time slot; receiving said uplink signal using an antenna array having selectable patterns; measuring a relative time offset of the reference signal when received in said uplink signal with respect to said downlink time slot; determining if said time offset is within a determined range and judging a received uplink signal as valid only if the time offset is within said range; and selecting a pattern of said antenna array according to a judgment result in said determining step. - View Dependent Claims (11, 12, 13, 14)
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15. A system for tracking an uplink signal received at a base station of a radio communications network, comprising:
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transmitter means at a network base station for transmitting a downlink signal for reception by a network subscriber validly assigned to the base station, including means for defining a downlink time slot during which the downlink signal is transmitted; means for defining an uplink time slot during which said subscriber transmits an uplink signal for reception at the base station; means for including in said uplink signal a reference signal at a certain time with respect to said uplink time slot; antenna array means at said base station for receiving said uplink signal, including means for selecting one of a number of different receiving antenna patterns; means at said base station for measuring a relative time offset of the reference signal when received in said uplink signal with respect to said downlink time slot; means for determining if said time offset is within a determined range, and for judging a received uplink signal as valid only if the time offset is within said range; and means for selecting a pattern of said antenna array according to a judgment result in said determining step. - View Dependent Claims (16, 17)
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Specification