Cooperative-MIMO Communications
First Claim
1. A method for calculating antenna-array weights in a cooperative antenna array comprising a plurality of wireless devices, the method comprising:
- calculating branch metrics based on at least one fitness function for a plurality of possible state transitions between two successive states,calculating path metrics for a plurality of possible paths constituted by successive state transitions and ending in each of said states, andselecting at least one path for each of said states having an optimal path-metric value.
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Abstract
Spatial subchannel codes for wireless devices operating in a cooperative antenna array are generated using an asymptotically optimal decoding algorithm, such as a trellis-exploration algorithm similar to the Viterbi algorithm. A trellis may be constructed using a number of desired subchannels, at least one code length, and a number of code-chip parameters. A fitness function is derived from a mathematical relationship between codes, and may include some measure of correlation of the codes. The selected codes correspond to paths having optimal path metrics derived from the fitness function. Multiple iterations through the trellis may be performed to refine a selection of the codes.
108 Citations
25 Claims
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1. A method for calculating antenna-array weights in a cooperative antenna array comprising a plurality of wireless devices, the method comprising:
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calculating branch metrics based on at least one fitness function for a plurality of possible state transitions between two successive states, calculating path metrics for a plurality of possible paths constituted by successive state transitions and ending in each of said states, and selecting at least one path for each of said states having an optimal path-metric value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus configured for calculating antenna-array weights of a cooperative antenna array comprising a plurality of wireless devices, comprising:
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a branch metrics module configured for computing a branch metric for each of a plurality of antenna-array weight candidates, and an accumulated metrics module configured to add at least one branch metric to at least one previous path metric and select at least one path based on an optimum path metric.
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- 12. The apparatus recited in claim 12, further comprising a survivor storage and updating module configured to store decisions generated by the accumulated metrics module and to perform trace back.
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14. A machine-readable medium comprising instructions encoded thereon and executable to:
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calculate branch metrics based on at least one fitness function for a plurality of possible state transitions between two successive states, calculate path metrics for a plurality of possible paths constituted by successive state transitions and ending in each of said states, and select at least one path having an optimal path-metric value, the at least one path corresponding to optimal weights to be used in an antenna array.
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15. A method for calculating antenna-array weights in a cooperative antenna array comprising a plurality of wireless devices, the method comprising:
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constructing a trellis for a number K of spatial sub-channels, a number of antenna-array elements N, and a number L of antenna-weighting parameters, generating a fitness function based on estimated antenna-array weights, and employing a trellis-exploration algorithm for producing updated antenna-array weights. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification