Methods and a device for multi-resolution precoding matrix indicator feedback
AssigneeMotorola Mobility LLC
InventorSandeep H. Krishnamurthy
Life of this patent
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Abstract
Disclosed are methods and a device for Multi-resolution PMI Feedback. In one implementation, a user equipment finds a rank 1 or rank 2 Precoding Matrix Indicator based on the signal channel matrix and interference covariance matrix, defines an error vector, obtains an orthonormal basis for the projection matrix, finds the (M−1)-dimensional vector from a codebook (e.g., oversampled Discrete Fourier Transform) with the minimum Euclidean distance, and sends a feedback representing to the base station regarding the vector that it found in the codebook.
Claims25
A method comprising:
- receiving a pilot signal from a transmission point;
- determining, based on the pilot signal, a first channel direction vector v of size M×1;
- selecting, from a first codebook, a first precoding vector p, wherein p is a representation of v;
- determining, based on v and on p, a representation Lû of the normalized error vector {tilde over (e)}, wherein:
- {tilde over (e)}=(v−p)/∥v−p∥2,
- û a (M−1)×1 vector from a second codebook C, and
- L is a matrix with (M−1) columns that are orthogonal top;
- and
- sending a report to a serving cell based at least in part on p and at least in part on û.
A method comprising:
- receiving a pilot signal from a transmission point;
- estimating a first channel direction vector vk,1 from the pilot signal;
- obtaining a first precoding vector vk,1 from a first codebook;
- determining, based on vk,1, a first derived direction vector vk,1;
- determining a first residue vector {tilde over (e)}k,1 based vk,1− vk,1;
- determining a first projection {tilde over (e)}k,1H vl,1 between {tilde over (e)}k,1 and a second precoding vector vl,1 from a second codebook;
- and
- sending a report to a serving cell based at least in part on {tilde over (e)}k,1H vl,1.
A method comprising:
- receiving a pilot from a transmission point;
- estimating the channel matrix Hk from the pilot;
- estimating an interference and noise covariance matrix Rzk based on the pilot signal;
- determining a first vector p from a first codebook that satisfies at least one of the following criteria:
- maximize trace(pHHkHRzk−1Hkp);
- and
- minimize the Euclidean distance ∥v−p∥2, where v is the principal eigenvector of HkHRzk−1Hk;
- and
- sending a report to a serving cell based at least in part on p.
A UE comprising:
- a processor;
- a plurality of transceivers;
- and
- an antenna array including a plurality of antennas, wherein each antenna is connected to at least one of the plurality of transceivers;
- wherein the UE receives a radio frequency pilot signal from a transmission point via the antenna array;
- wherein one or more of the plurality of transceivers converts the pilot signal to digital signals and provides the digital signals to the processor;
- and
- wherein the processor performs steps comprising:
- determining, based on the pilot signal, a first channel direction vector v of size M×1;
- selecting, from a first codebook, a first precoding vector p, wherein p is a representation of v;
- determining, based on v and on p, a representation Lû of the normalized error vector {tilde over (e)}, wherein:
- e=(v−p)/∥v−p∥2,
- u a (M−1)×1 vector from a second codebook C, and
- L is a matrix with (M−1) columns that are orthogonal to p;
- and
- sending, via at least one of the plurality of transceivers and via the antenna array, a report to a serving cell based at least in part on p and at least in part on û.
Dependencies are inferred from the claim text.