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1. WO2012059555 - SELF-INTERFERENCE SUPPRESSION IN FULL-DUPLEX MIMO RELAYS

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS

A method for self-interference suppression in a relay (306) for wireless communication, wherein said relay (306) being a part of a communication channel between a transmitter (301 ) and a receiver (305) in a wireless communication system (300) , said relay (306) being arranged for receiving a signal r(«) transmitted from said transmitter (301 ), and transmitting a self-interference suppressed transmit signal xr(«) to said receiver (305), said communication channel having a transmit channel, defined by a transmit channel matrix (Hi) between said transmitter (301 ) and said relay (306) , a receive channel, defined by a receive channel matrix (H2) between said relay (306) and said receiver (305) , and a self-interference channel between an relay output and a relay input of said relay (306), the self-interference channel being defined by a self-interference channel matrix (H0), c h a r a c t e r i z e d in that the method comprises the steps:

- receiving (401 ) at the relay input of said relay (306) a receive signal r(«) transmitted from said transmitter (301 ) over said transmit channel;

- determining (402) a receive suppression filter matrix Wr (302) , in said relay (306), based on said transmit channel matrix (Hi) and said self-interference channel matrix (H0) ;

- determining (403) a transmit suppression filter matrix W, (304), in said relay (306), based on said receive suppression filter matrix Wr (302), said receive channel matrix (H2), and said self-interference channel matrix (H0) ;

- determining (404) a self-interference suppressed transmit signal xr(«) by applying said receive suppression filter matrix Wr, a relay amplification matrix G (303) and said transmit suppression filter matrix Wt, to said received signal r(«); and

- transmitting (405) said self-interference suppressed transmit signal xr(«) from said relay (306) over said receive channel to said receiver (305).

The method according to claim 1 , wherein said receive signal r(«) is given by

r («) = Htxs («) + H0xr («) + nR («)

wherein xr(«) is the transmitted relay signal, and nR(«) is the noise contribution at the relay (306).

The method according to any one of claims 1 -2, wherein said receive suppression filter matrix Wr (302) is determined by the optimal receive suppression matrix which is given by

^,ορίΗ0Η^ )-Ί2

wherein the columns of U are the corresponding generalized eigenvectors of the matrix (H0H r//2H;H (H0H r//2

The method according to any one of claims 1 -3, wherein said transmit suppression filter matrix Wt (304) is determined by the optimal transmit suppression matrix which is given by

wt,opt = (H»H0y1/2U

wherein H0 =Wr optH0 and matrix V is obtained by applying a generalized eigenvalue decomposition of the matrix (H o H 0y1/2 H 2 2(H o H 0y1/2 , wherein the columns of matrix H are the corresponding eigenvectors.

The method according to any one of claims 1 -4, wherein said forming (404) of said self-interference suppressed transmit signal xr(«) is done according to xr(n) = WtGWrr(n) .

A relay (700) adapted for self-interference suppression in a wireless communication system, wherein said relay (700) being a part of a communication channel between a transmitter (701 ) and a receiver (702) in a wireless communication system, wherein said communication channel having a transmit channel, defined by a transmit channel matrix (Hi) between said transmitter (701 ) and said relay (700), a receive channel defined by a receive channel matrix (H2), between said relay (700) and said receiver (702), and a self-interference channel between an relay output and a relay input of said relay (700), the self-interference channel being defined by a self-interference channel matrix (H0), said relay (700) comprising:

a receiver unit (703) adapted to receive a receive signal r(«) transmitted from said transmitter over said transmit channel;

- a first processing unit (704) adapted to determine a receive suppression filter matrix Wr, based on said transmit channel matrix (Hi) and said self-interference channel matrix (H0) ;

- a second processing unit (705) adapted to determine a transmit suppression filter matrix wt, based on said receive suppression filter matrix Wr (704), said receive channel matrix (H2), and said self-interference channel matrix (H0) ;

- a third processing unit (706) adapted to determine a relay amplification matrix G;

- a fourth processing unit (707) adapted to produce a self- interference suppressed transmit signal xr(«) by applying said receive suppression filter matrix Wr from said first processing unit (704), said transmit suppression filter matrix W, from said second processing unit (705), and said relay amplification matrix G from said third processing unit (706) to said receive signal r(«), wherein said fourth processing unit (707) is further adapted to supply said self-interference suppressed transmit signal xr(«) to a transmitter unit (708); and

- said transmitter unit (708) is adapted to receive said self- interference suppressed transmit signal xr(«) from said fourth processing unit (707), and adapted to transmit said self- interference suppressed transmit signal xr(«) to said receiver (702) over said transmit channel.

The relay (700) according to claim 6, wherein said receive signal r(«) received by said receiver (703) is given by

r («) = Htxs («) + H0xr («) + nR («)

wherein xr(«) is the transmitted relay signal, and nR(«) is the noise contribution at the relay (700).

The relay (700) according to any one of claims 6-7, wherein said first processing unit (704) is further adapted to determine said receive suppression filter matrix Wr by determining the optimal receive suppression matrix according to

^,ορίΗ0Η^ )-Ί2

wherein the columns of U are the corresponding generalized eigenvectors of the matrix (H0H r//2H;H (H0H r//2

The relay (700) according to any one of claims 6-8, wherein said second processing unit (705) is further adapted to determine said transmit suppression filter matrix Wt by calculating the optimal transmit suppression matrix according to

w,opt = (H»H0y1/2U

wherein H0 = Wr optH0 and the matrix t/ is obtained by the generalized

eigenvalue decomposition of the matrix (H"H0y1/2H"H2 (H"H0 y1/2 ; and its columns are the corresponding eigenvectors.

10. The relay (700) according to any one of claims 6-9, wherein said producing, in said fourth processing unit (707), of said self-interference suppressed transmit signal xr(«) is done according to xr (n) = WtGWrr(n)