Dynamic space division duplex (SDD) wireless communications with multiple antennas using self-interference cancellation

Patent metadata

Field	Value
Publication number	US-9019849-B2
Application number	US-201113290677-A
Country	US
Kind code	B2
Filing date	Nov 7, 2011
Priority date	Nov 7, 2011
Publication date	Apr 28, 2015
Grant date	Apr 28, 2015

Abstract

A system and method to perform Full Duplex (FD) Space Division Duplex (SDD) communication using a Self-Interference Cancelling (SIC) precoder that applies different antenna phase shifts and amplitude scales to the transmitted signals to force them to be in the null space of the selected receive antennas. Thus, a wireless communication unit can place nulls at each of its receive antennas digitally at baseband for one or more frequency bands. The SIC precoder may be computed based on the self-interference channel from the transmit chain(s) to the receive chain(s). Different SIC precoders may be adaptively selected and stored digitally for different frequency bands. Subsequent single or multi-user precoder can be applied in concatenation with the SIC precoder to transmit signals to one or more users while receiving signals from one or more users simultaneously over the same frequency band.

First claim

What is claimed is:

1. A method of providing full-duplex communication in a pre-determined frequency band using a wireless communication unit having a plurality of antennas, the method comprising the steps of:
the wireless unit receiving one or more receive data streams in the pre-determined frequency band utilizing a first subset of the plurality of antennas, wherein the first subset includes at least one antenna from the plurality of antennas as a receive antenna;
the wireless unit simultaneously transmitting one or more transmit data streams in the pre-determined frequency band utilizing a second subset of the plurality of antennas, wherein the second subset includes less than or equal to a total number of antennas in the plurality of antennas as transmit antennas, wherein at least one antenna is shared for simultaneous transmission and reception;
the wireless unit determining a Self-Interference Cancelling (SIC) precoder based on a null space of an estimate of a Self-Interference (SI) channel matrix for the predetermined frequency band; and
based on the determined SIC precoder, the wireless unit adjusting relative amplitudes and relative phases of radio signals carrying the transmit data streams that are transmitted through the transmit antennas in the pre-determined frequency band such that destructive interference reduces a magnitude of the radio signals received at each receive antenna when transmitting in the pre-determined frequency band.

2. The method of claim 1 , wherein the first subset of the plurality of antennas includes a fixed number of antennas from the plurality of antennas to operate as receive antennas.

3. The method of claim 1 , wherein the pre-determined frequency band includes any frequency band from a plurality of pre-determined frequency bands.

4. The method of claim 3 , wherein the step of the wireless unit determining the SIC precoder includes:
the wireless unit determining a plurality of SIC precoders, each SIC precoder corresponding to one of the plurality of pre-determined frequency bands; and
the wireless unit selecting the SIC precoder from the plurality of SIC precoders depending on which of the pre-determined frequency bands the radio signals are transmitted in.

5. The method of claim 1 , wherein the step of the wireless unit receiving data streams utilizing the first subset of the plurality of antennas includes:
the wireless unit dynamically selecting one or more of the plurality of antennas to be included in the first subset in a frequency-dependent manner.

6. The method of claim 5 , wherein the step of the wireless unit dynamically selecting one or more of the plurality of antennas includes:
the wireless unit selecting one or more of the plurality of antennas to be included in the first subset associated with the pre-determined frequency band in such a manner as to maximize a weighted sum of a transmission throughput and a reception throughput, wherein the transmission throughput is associated with Multiple-Input Multiple-Output (MIMO) transmissions from the wireless unit to a first plurality of users, and wherein the reception throughput is associated with MIMO receptions by the wireless unit from a second plurality of users.

7. The method of claim 1 , wherein the step of the wireless unit receiving data streams utilizing the first subset of the plurality of antennas includes:
the wireless unit dynamically selecting one or more of the plurality of antennas to be included in the first subset in a time-dependent manner.

8. The method of claim 1 , wherein the step of the wireless unit transmitting one or more transmit data streams includes:
the wireless unit transmitting the one or more transmit data streams to a first plurality of users, and
wherein the step of the wireless unit receiving one or more receive data streams includes:
the wireless unit receiving the one or more receive data streams from a second plurality of users.

9. The method of claim 1 , wherein the step of the wireless unit determining the SIC precoder further includes:
the wireless unit determining the SIC precoder based on an estimate of a Self Interference (SI) channel matrix for the pre-determined frequency band, wherein the SI channel matrix includes a plurality of matrix elements, and wherein a matrix element in an i th row and a j th column of the SI channel matrix represents a channel response from a j th transmit antenna in the plurality of antennas to an i th receive antenna at a given frequency in the pre-determined frequency band corresponding to a communication channel established between the j th transmit antenna and the i th receive antenna, wherein both “I” and “j” are integers and greater than or equal to two; and
wherein the step of the wireless unit adjusting the relative amplitudes and relative phases of the radio signals further includes:
applying the SIC precoder to each transmission in the pre-determined frequency band from each transmit antenna, thereby shaping all transmissions to collectively destructively interfere at each receive antenna upon being transmitted from the corresponding transmit antennas.

10. The method of claim 9 , wherein the step of the wireless unit determining the SIC precoder includes one of the following:
the wireless unit determining the SIC precoder as eigenvectors of a projection matrix K 1 (f)≡I−Ĥ SI H (f)(Ĥ SI (f)Ĥ SI H (f)) −1 Ĥ SI (f) that correspond to non-zero eigenvalues of K 1 (f), wherein “I” is an identity matrix, Ĥ SI (f) is the estimate of the SI channel matrix H SI (f), Ĥ SI H (f) is a Hermitian transpose of Ĥ SI (f), and f is the given frequency in the pre-determined frequency band;
the wireless unit determining the SIC precoder as eigenvectors of K 2 (f)≡Ĥ SI H (f)(Ĥ SI (f)Ĥ SI H (f)) −1 Ĥ SI (f) that correspond to a zero eigenvalue of K 2 (f); and
the wireless unit determining the SIC precoder as a matrix whose columns represent a set of orthonormal basis vectors of a right null space of Ĥ SI (f).

11. The method of claim 9 , further comprising the steps of:
the wireless unit transmitting a first pre-determined number of pilot signals, wherein each pilot signal in the first pre-determined number of pilot signals is transmitted in the pre-determined frequency band utilizing a third subset of the transmit antennas, wherein the third subset includes at least one of the transmit antennas;
the wireless unit determining an initial version of the estimate of the SI channel matrix based on receptions of the first pre-determined number of pilot signals at each receive antenna; and
the wireless unit determining an initial version of the SIC precoder based on the initial version of the estimate of the SI channel matrix.

12. The method of claim 11 , further comprising the step of:
the wireless unit iteratively refining the initial versions of the estimate of the SI channel matrix and the SIC precoder until a pre-determined criterion is satisfied.

13. The method of claim 12 , wherein the step of the wireless unit iteratively refining the initial versions of the estimate of the SI channel matrix and the SIC precoder includes:
the wireless unit applying the initial version of the SIC precoder to a second pre-determined number of pilot signals;
the wireless unit transmitting the SIC precoder-applied second pre-determined number of pilot signals in the pre-determined frequency band utilizing a fourth subset of the transmit antennas, wherein the fourth subset of the transmit antennas includes less than or equal to all transmit antennas;
the wireless unit determining an updated version of the estimate of the SI channel matrix based on receptions of the second pre

Assignees

• Hui Dennis
• Guey Jiann-Ching
• Ericsson Telefon Ab L M

Inventors

• Hui Dennis
• Guey Jiann-Ching

Classifications

• H04B7/0478

  Special codebook structures directed to feedback optimisation · CPC title

• H04L5/14 Primary

  Two-way operation using the same type of signal, i.e. duplex · CPC title

• H04B7/0617

  for beam forming · CPC title

• H01Q3/2611

  Means for null steering; Adaptive interference nulling · CPC title

• H04B7/0874

  using subgroups of receive antennas · CPC title