Method and processing arrangement for joint processing of uplink data
View Patent ↗The invention relates to a method for joint processing of uplink data (g(n), s(n)) transmitted from at least one user equipment (UE 1 , UE 2 ) to a plurality of coordinated reception points (BS A , BS B ) of a wireless communication system ( 1 ), the method comprising: estimating and preferably compensating for individual propagation delays of the uplink data (g(n), s(n)) transmitted from one of the user equipments (UE 1 , UE 2 ) to the coordinated reception points (BS A , BS B ), and compensating a timing difference between a propagation delay of a coordinated reception point (BS A , BS B ) which serves the user equipment (UE 1 , UE 2 ) and at least one propagation delay of at least one coordinated reception point (BS B , BS A ) which does not serve the user equipment (UE 1 , UE 2 ) for performing the joint processing of the uplink data (g(n), s(n)), wherein the step of compensating the timing difference comprises modifying a channel matrix (H) associated with uplink channels from the at least one user equipment (UE 1 , UE 2 ) to the coordinated reception points (BS A , BS B ). The invention also relates to a processing arrangement (BS A , BS B , 2 ) adapted for performing the method.
1. A method for supporting joint processing of uplink data between a plurality of user equipments and a plurality of coordinated reception points, the method comprising:
estimating individual propagation delays of the uplink data between the plurality of user equipments and the plurality of coordinated reception points;
compensating a timing difference between a propagation delay of a coordinated reception point which serves at least one of the plurality of user equipments and at least one propagation delay of at least one coordinated reception point which does not serve the at least one of the plurality of user equipments by modifying a channel matrix associated with uplink channels from the at least one of the plurality of user equipments to the plurality of coordinated reception points by:
performing a phase-shift on channel coefficients of the channel matrix associated with the uplink channels from the at least one of the plurality of user equipments and the at least one non-serving coordinated reception point; and
modifying an amplitude of the channel coefficients of the channel matrix associated with the uplink channels from the at least one of the plurality of user equipments and the at least one non-serving coordinated reception point.
2. The method according to claim 1 , further comprising compensating individual propagation delays of the uplink data transmitted from the at least one of the plurality of user equipments to the plurality of coordinated reception points.
3. The method according to claim 1 , wherein modifying the amplitude of the channel coefficients of the channel matrix is performed by multiplying the channel coefficients with a real number smaller than one.
4. The method according to claim 1 , wherein the uplink data are arranged in an orthogonal frequency division multiplex (OFDM) transmission scheme, and the method further comprises generating an individual channel matrix for sub-carriers of the OFDM transmission scheme.
5. The method according to claim 1 , further comprising: performing a joint calculation of receiver weights for the at least one of the plurality of user equipments, the calculation being based on the channel matrix as modified.
6. The method according to claim 1 , further comprising: compensating the propagation delay from a user equipment to its serving coordinated reception point by adjusting the position of a processing window for performing a time-to-frequency-domain transformation, in particular a Fast-Fourier-Transformation (FFT) on symbols of the uplink data.
7. The method according to claim 1 , wherein the joint processing comprises: performing a joint time-to-frequency domain transformation, in particular a Fast-Fourier-Transformation (FFT) on time domain samples of the uplink data of the plurality of user equipments having similar propagation delays to a common non-serving coordinated reception point.
8. The method according to claim 1 , further comprising: choosing a repetition rate for estimating the propagation delay of the uplink data transmitted from the at least one of the plurality of user equipments to the plurality of coordinated reception points in dependence of the speed of movement of the at least one of the plurality of user equipments.
9. The method according to claim 1 , wherein the joint processing comprises: performing a Fast-Fourier-Transformation (FFT) on a number of time domain samples of the uplink data in a processing window, the method further comprising: shifting the processing window by subtracting a discrete Fourier transform (DFT) contribution for sub-carriers of one or more time domain samples at one end of the processing window and adding a DFT contribution for the sub-carriers of a corresponding number of time domain samples at the other end of the processing window.
10. A non-transitory computer-readable medium storing instructions that, when executed by a computer, cause the computer to implement a method for supporting joint processing of uplink data between a plurality of user equipments and a plurality of coordinated reception points, the method comprising:
estimating individual propagation delays of the uplink data between the plurality of user equipments and the plurality of coordinated reception points:
compensating a timing difference between a propagation delay of a coordinated reception point which serves at least one of the plurality of user equipments and at least one propagation delay of at least one coordinated reception point which does not serve the at least one of the plurality of user equipments by modifying a channel matrix associated with uplink channels from the at least one of the plurality of user equipments to the plurality of coordinated reception points by:
performing a phase-shift on channel coefficients of the channel matrix associated with the uplink channels from the at least one of the plurality of user equipments and the at least one non-serving coordinated reception point; and
modifying an amplitude of the channel coefficients of the channel matrix associated with the uplink channels from the at least one of the plurality of user equipments and the at least one non-serving coordinated reception point.
11. A processing arrangement for supporting joint processing of uplink data between a plurality of user equipments and a plurality of coordinated reception points, the processing arrangement comprising: the plurality of coordinated reception points and a processing unit operatively connected to the plurality of coordinated reception points, wherein the processing unit is configured to:
estimate individual propagation delays of the uplink data between the plurality of user equipments and the plurality of coordinated reception points;
compensate a timing difference between a propagation delay of a coordinated reception point which serves at least one of the plurality of user equipments and a propagation delay of at least one coordinated reception point which does not serve the at least one of the plurality of user equipments by modifying a channel matrix associated with uplink channels from the at least one of the plurality of user equipments to the plurality of coordinated reception points by:
performing a phase-shift on channel coefficients of the channel matrix associated with the uplink channels from the at least one of the plurality of user equipments and the at least one non-serving coordinated reception point; and
modifying an amplitude of the channel coefficients of the channel matrix associated with the uplink channels from the at least one of the plurality of user equipments and the at least one non-serving coordinated reception point.
12. The processing arrangement according to claim 11 , wherein the processing unit is further configured to compensate individual propagation delays of the uplink data transmitted from the at least one of the plurality of user equipments to the plurality of coordinated reception points.
13. The processing arrangement according to claim 11 , wherein the processing unit is configured to perform the amplitude modification by multiplying the channel coefficients with a real number smaller than one.
14. The processing arrangement according to claim 11 , wherein the processing unit is further configured to perform a joint calculation of receiver weights for the at least one of the plurality of user equipments, the calculation being based on the channel matrix as modified.
15. The processing arrangement according to claim 11 , wherein the uplink data are arranged in an orthogonal frequency division multiplex (OFDM) transmission scheme, and wherein the processing unit is further configured to generate an individual channel matrix for sub-carriers of the OFDM transmission scheme.