Determining SINR in a communications system
First Claim
1. A method of determining SINR (signal to interference plus noise power ratio) in a communications system in which diversity path signals, each comprising a plurality of time division multiplexed symbols in a time slot including known symbols constituting a reference signal, are combined with respective weights to produce a combined signal for demodulation, the method comprising the steps of:
- determining a correlation matrix of the diversity path signals and a reference signal correlation vector; and
determining SINR from the correlation matrix and the reference signal correlation vector.
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Abstract
Diversity path signals, each comprising time division multiplexed symbols in a time slot including known symbols constituting a reference signal, are combined with respective weights to reduce co-channel interference. The weights are determined, from a correlation matrix and a reference signal correlation vector, using a sliding window starting with synchronization symbols and/or CDVCC (coded digital verification color code) symbols as the known symbols. SINR (signal to interference plus noise ratio) is determined for each window position from elements of the correlation matrix and the reference signal correlation vector. The determined SINRs are averaged through the time slot, over a plurality of time slots, and for the diversity paths to provide an accurate determination of SINR within a short period. The SINR provides a reliable signal quality parameter that is useful in a cellular communications system for procedures such as hand-off, adaptive channel allocation, dynamic power control, and cell tiering.
255 Citations
20 Claims
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1. A method of determining SINR (signal to interference plus noise power ratio) in a communications system in which diversity path signals, each comprising a plurality of time division multiplexed symbols in a time slot including known symbols constituting a reference signal, are combined with respective weights to produce a combined signal for demodulation, the method comprising the steps of:
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determining a correlation matrix of the diversity path signals and a reference signal correlation vector; and determining SINR from the correlation matrix and the reference signal correlation vector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of determining SINR (signal to interference plus noise ratio) in a communications system in which diversity path signals are combined with respective weights, the diversity path signals each comprising a plurality of time division multiplexed symbols in a time slot, comprising the steps of:
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determining a correlation matrix of the diversity path signals; determining a reference signal correlation vector using as a reference signal known and/or determined symbols in the time slot; determining SINR for each diversity path from elements of the correlation matrix and the reference signal correlation vector; and averaging the determined SINRs for the diversity paths. - View Dependent Claims (14, 15, 16)
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17. A receiver for receiving via at least two diversity paths signals each comprising a plurality of time division multiplexed symbols in a time slot including known symbols constituting a reference signal, comprising:
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buffers for storing symbols of the diversity path signals; a weight calculating unit for determining weights for combining symbols of the diversity path signals from the buffers in dependence upon a correlation matrix of the diversity path signals and a reference signal correlation vector; a signal combiner arranged to combine symbols of the diversity path signals from the buffers in accordance with the respective weights determined by the weight calculating unit to produce a combined signal; and an SINR (signal to interference plus noise power ratio) estimator responsive to elements of the correlation matlix and the reference signal correlation vector for determining SINR of at least one of the diversity path signals. - View Dependent Claims (18, 19, 20)
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Specification