Multi-receiving terminal echo cancellation method and system

Patent metadata

Field	Value
Publication number	US-9136905-B2
Application number	US-201213816542-A
Country	US
Kind code	B2
Filing date	Apr 9, 2012
Priority date	Dec 29, 2011
Publication date	Sep 15, 2015
Grant date	Sep 15, 2015

Abstract

Disclosed is a method and system for multi-receiving terminal echo cancellation Echo filters performs echo filtering on receiving terminal signals in M channels to obtain filtered receiving terminal signals in M channels. The filtered receiving terminal signals in M channels are subtracted from a transmitting terminal signal to obtain a system output signal in which receiving terminal echoes have been cancelled. The receiving terminal signals in M channels are buffered. A decorrelation matrix according to each of the receiving terminal signals in M channels is calculated. The decorrelation matrix decomposes the buffered receiving terminal signals in M channels into decorrelated receiving terminal signals in M channels. Update amounts of the echo filters are calculated according to the decorrelation matrix, the decorrelated receiving terminal signals in M channels and the system output signal that is fed back.

First claim

The invention claimed is:

1. A multi-receiving terminal echo cancellation method suitable for use in a communication apparatus comprising M receiving terminals, M being a natural number greater than or equal to 2, the method comprising
performing echo filtering on receiving terminal signals in M channels by means of echo filters to obtain filtered receiving terminal signals in M channels, and subtracting the filtered receiving terminal signals in M channels from a sending terminal signal to obtain a system output signal in which receiving terminal echoes have been cancelled; and
buffering the receiving terminal signals in M channels by means of buffers at the same time, calculating a decorrelation matrix according to each of the receiving terminal signals in M channels that are buffered within a preset length, decomposing the buffered receiving terminal signals in M channels into decorrelated receiving terminal signals in M channels by means of the decorrelation matrix, and calculating update amounts of the echo filters according to the decorrelation matrix, the decorrelated receiving terminal signals in M channels and the system output signal that is fed back.

2. The method of claim 1 , wherein the calculating a decorrelation matrix according to each of the receiving terminal signals in M channels that are buffered within a preset length comprises:
performing an (M−1)-step iterative operation, the initial input of the iterative operation is one signal matrix x (0) ′ with L D rows and M columns that is constituted by the buffered receiving terminal signals in M channels, wherein

x

(
0
)

′

=

[

x

1
⁢

(
0
)

′

⁢

⁢

x

2
⁢

(
0
)

′

⁢

⁢
…
⁢

⁢

x

i
⁡

(
0
)

′

⁢

⁢
…
⁢

⁢

x

M
⁡

(
0
)

′

]

,

⁢

x

i
⁡

(
0
)

′

=

x
i

=

[

x
i

⁡

(
1
)

x
i

⁡

(
2
)

⋮

x
i

⁡

(

L
D

)

]

x i represents the i th channel's buffered receiving terminal signal with a length of L D , L D represents a data length buffered within a preset time length, and 1≦i≦M;
the decorrelation matrix De 1 is calculated in the first iterative step:

De

(
1
)

=

[

1

-

c

1
,
2

…

-

c

1
,
M

Assignees

• Lou Shasha
• Goertek Inc

Inventors

• Lou Shasha

Classifications

• H04B3/231

  Echo cancellers using readout of a memory to provide the echo replica · CPC title

• H04M9/082

  using echo cancellers (echo cancellers per se H04B3/23) · CPC title

• H04B3/20 Primary

  Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other · CPC title

• H04M9/08

  Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic · CPC title

• H04M9/00 Primary

  Arrangements for interconnection not involving centralised switching · CPC title