System and method for tuning transmission parameters in multi-user multiple-input-multiple-output systems with aged and noisy channel estimation

• US 9,071,435 B2
• Filed: 08/09/2011
• Issued: 06/30/2015
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: Celeno Communications, Ltd.
• Original Assignee: Celeno Communications, Ltd.
• Inventors: Shany, Yaron, Shapira, Nir, Kirshenberg, Gilad
• Primary Examiner(s): Magloire, Vladimir
• Assistant Examiner(s): HEIBER, SHANTELL LAKETA
• Application Number:
  US13/206,018
• Publication Number:
  US 20120063336A1
• Time in Patent Office: 1,421 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0656 at the transmitter, e.g. error detection at base station
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER

Abstract

System and method for tuning transmission parameters based on estimated ratio between a signal to an estimated interference plus noise (SINR) of a user, in a multiple-user multiple-input multiple-output (MU-MIMO) communication system, the method including obtaining channel state information (CSI) related to a channel from an access point (AP) to users that participate in a next MU-MIMO transmission, wherein the AP, and the users pertain to the MU-MIMO communication system, obtaining error coefficients related to errors related to channel-ageing and to estimation noise of the CSI, and calculating the estimated SINR, wherein the estimated interference is related to power of the other users and to the estimated channel magnitude the user u, and to the error coefficients, wherein the estimated channel magnitude is derived from the CSI.

Claims

1. A method for tuning transmission parameters based on estimated ratio between a signal to an estimated interference plus noise (SINR) of a user, in a multiple-user multiple-input multiple-output (MU-MIMO) communication system, the method comprising:

obtaining channel state information (CSI) related to a channel from an access point (AP) to the user, denoted u, and to channels from the AP to other users wherein the user and the other users pertain to the MU-MIMO communication system and participate in a MU-MIMO transmission;

obtaining error coefficients related to errors related to channel-ageing and to estimation noise of the CSI; and

calculating the estimated SINR, wherein the estimated interference caused by the signal transmitted to the other users by the AP and affecting the signal received by said user is related to power of the other users and to the estimated channel magnitude of the user u, and to the error coefficients, wherein the estimated channel magnitude is derived from the CSI;

selecting the transmission parameters based on the estimated SINR; and

transmitting data to the user using the selected transmission parameters.

2. The method of claim 1, wherein the error coefficients comprise a first coefficient, and wherein the estimated interference comprises an ageing term, the aging term equals the power allocated to the other users multiplied by the estimated squared channel magnitude of said user, scaled by the first coefficient.

3. The method of claim 1, wherein the error coefficients comprise a second coefficient, and wherein the estimated interference comprises a noise term, the noise term equals the power allocated to the other users, scaled by the second coefficient.

4. The method of claim 1, wherein the error coefficients comprises a third coefficient and wherein the estimated interference comprises a cross term, the cross term equals the power allocated to the other users multiplied by the estimated channel magnitude of said user, scaled by the third coefficient.

5. The method of claim 1, wherein a plurality of values for the error coefficients are used for different channel aging durations, different Doppler frequencies and different subcarrier grouping values in a multi-carrier system.

6. The method of claim 1, further comprising:

calculating the error coefficients based on estimation of the estimated SINR at the user.

7. A method for tuning transmission parameters based on estimated ratio between a signal to an estimated interference plus noise (SINR) of a user, in a multiple-user multiple-input multiple-output (MU-MIMO) communication system, the method comprising:

obtaining channel state information (CSI) related to a channel from an access point (AP) to the user, denoted u, and to channels from the AP to other users wherein the user and the other users pertain to the MU-MIMO communication system and participate in a next MU-MIMO transmission;

calculating transmit beamforming matrix b_u based on said CSI;

obtaining error coefficients related to errors related to channel-ageing and to estimation noise of the CSI; and

calculating the estimated SINR, wherein the estimated MU related interference caused by the signal transmitted to the other users by the AP and affecting the signal received by said user includes a combination of up to three components, each multiplied by a respective dedicated error coefficient, the first component is the power allocated to the other users multiplied by the energy of the channel to the user, the second component is the power allocated to the other users, and the third component is the power allocated to the other users multiplied by the magnitude of the channel to the user.

8. The method of claim 7, wherein transmission is performed over a plurality of subcarriers, and wherein the obtaining of the CSI comprises obtaining the CSI for substantially each subcarrier and wherein the calculating the estimated SINR comprises:

calculating a plurality of per-subcarrier estimated SINRs, each for a specific subcarrier; and

unifying the plurality of per-subcarrier estimated SINRs to receive the estimated SINR.

9. The method according to claim 7, wherein the transmission is performed over a plurality of sub-carriers, and wherein the first coefficient multiplies the average of the power allocated to other users multiplied by the average of the channel to the user, the second coefficient multiplies the average power allocated to other users by the average magnitude of the channel to the user, and the third coefficient multiplies the average power to the other users, wherein all averages are across sub-carriers.

10. The method according to claim 7, wherein an initial MCS is selected based on a goodness measure, finding an equivalent SNR denoted {circumflex over (γ

)}<sub>equ—

u</sub><sup>no−

err.</sup> that corresponds with the initial MCS,

wherein the calculating of the estimated SINR, denoted {circumflex over (γ

)}_u, is carried out by calculating;

{circumflex over (γ

)}_u<sup>−

1</sup>=({circumflex over (γ

)}<sub>equ—

u</sub><sup>no−

err.</sup>)<sup>−

1</sup>+({circumflex over (γ

)}_u^aging+noise)<sup>−

1</sup>

where {circumflex over (γ

)}_u^aging+noise is the SINR that accounts for the error coefficients.

11. The method according to claim 7, wherein the channel matrix H used in the SINR calculation is represented by D*V, wherein the D and the V are fed back by the user in an explicit sounding exchange, and wherein D and V are obtained by singular value decomposition of the original channel matrix.

12. The method according to claim 7, wherein the third component comprises a coefficient multiplied by a geometrical mean of the first and second error coefficients.

13. A data processing system comprising:

a processor; and

a non-transitory computer usable medium connected to the processor, wherein the computer usable medium contains a set of instructions for calculating a tuning transmission parameters based on estimated ratio between a signal to an estimated interference plus noise (SINR) of a user in a multiple-user multiple-input multiple-output (MU-MIMO) communication system, the MU-MIMO communication system comprises an access point (AP), the user and other users, wherein the processor is designed to carry out a set of instructions to perform a method of;

obtaining channel state information (CSI) related to a channel from the AP to the user, denoted u, and to channels from the AP to the other users, the CSI relates to estimated channel magnitudes;

obtaining error coefficients related to errors related to channel-ageing and to estimation noise of the CSI; and

calculating the estimated SINR, wherein the estimated interference caused by the signal transmitted to the other users by the AP and affecting the signal received by said user is related to power of the other users and to the estimated channel magnitude, and to the error coefficients,

wherein the processor is designed to carry out a set of instructions to further perform a method of;

selecting the transmission parameters based on the estimated SINR; and

transmitting data to the user using the selected transmission parameters.

14. The data processing system of claim 13 wherein the error coefficients comprise a first coefficient, and wherein the estimated interference comprises an ageing term, the aging term equals the power of the other users multiplied by the estimated squared channel magnitude, scaled by the first coefficient.

15. The data processing system of claim 13 wherein the error coefficients comprise a second coefficient, and wherein the estimated interference comprises a noise term, the noise term equals the power of the other users, scaled by the second coefficient.

16. The data processing system of claim 13 wherein the error coefficients comprises a third coefficient and wherein the estimated interference comprises a cross term, the cross term equals the power of the other users multiplied by the estimated channel magnitude, scaled by the third coefficient.