Methods and Devices for Determining Link Adaptation Parameters

Patent metadata

Field	Value
Publication number	US-2016204844-A1
Application number	US-201314911325-A
Country	US
Kind code	A1
Filing date	Aug 12, 2013
Priority date	Aug 12, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

The teachings relate to a method 100 performed in a network node 2 for determining a link adaptation parameter, SINR LA,i, for a wireless device 3. The network node 2 supporting a multi-antenna transmission mode comprising spatial multiplexing layers for transmission of data on a channel between the wireless device 3 and the network node 2. The method 100 comprises: determining 110 a channel covariance matrix H H H for the channel, wherein H is the channel matrix for the channel; approximating 120 a post-equalizer signal to interference plus noise ratio SINR approx ., for a spatial multiplexing layer i using the channel covariance matrix H H H; determining 130 an offset SINR offset , i to be the difference between a received signal to interference plus noise ratio SINR received and the approximated post-equalizer signal to interference plus noise ration SINR approx.,i , and determining 140 the link adaptation parameter SINR LA,i to be the approximated post-equalizer signal to interference plus noise ratio SINR approx,i compensated by the determined offset SINR offset . Corresponding network node, computer program and computer program products are also provided.

First claim

1 - 25 . (canceled)

26 . A method performed in a network node for determining a link adaptation parameter, SINR LA,i , for a wireless device, the network node supporting a multi-antenna transmission mode comprising spatial multiplexing layers for transmission of data on a channel between the wireless device and the network node, the method comprising:
determining a channel covariance matrix, H H H, for the channel, wherein H is the channel matrix for the channel, approximating a post-equalizer signal to interference plus noise ratio, SINR appox,i , for a spatial multiplexing layer i using the channel covariance matrix, H H H, determining an offset, SINR offset,i , to be the difference between a received signal to interference plus noise ratio, SINR received , and the approximated post-equalizer signal to interference plus noise ratio, SINR appox,i , and determining the link adaptation parameter SINR LA,i to be the approximated post-equalizer signal to interference plus noise ratio, SINR appox,i , compensated by the determined offset SINR offset .

27 . The method as claimed in claim 26 , wherein the offset, SINR offset,i , is stored in the network node and updated upon reception, from the wireless device, of a transmission on the channel.

28 . The method as claimed in claim 26 , comprising using the offset, SINR offset,i , for determining the link adaptation parameter, SINR LA,i , in link adaptation of a following transmission from the wireless device.

29 . The method as claimed in claim 26 , wherein the approximating of the post-equalizer signal to interference plus noise ratio, SINR appox,i , comprises using an approximated post-equalizer signal power S, a noise and interference covariance matrix R, and a factor γ accounting for inter-stream interference.

30 . The method as claimed in claim 29 , wherein the approximating of the post-equalizer signal to interference plus noise ratio, SINR appox,i , comprises using:

SINR

approx
,
i

=

S

i
,
i

R

i
,
i

·
γ

S
=

PW
H



H
H


HW

where S is an approximation of the post-equalizer signal power, and R is a noise and interference covariance matrix for the channel, W is a precoding vector for the transmission, and P is the transmit power of the transmission.

31 . The method as claimed in claim 29 , wherein the factor γ accounting for inter-stream interference is calculated according to:

γ
=

1

rank
=
1


G


/

(

g
11

·

g
22

)

rank
>
1

,

wherein

G
=

[

g
11

g
12

g
21

g
22

]

is equal to H H H.

32 . The method as claimed in claim 26 , wherein the determining of the offset, SINR offset,i , comprises applying a filtering to the determined offset, SINR offset,i according to:
SINR offsetFilt,i =(1−α)· SINR offsetFilt,i +α·SINR offset,i

wherein α is a filter coefficient.

33 . The method as claimed in claim 32 , comprising storing the filtered offset, SINR offsetFILT , in the network node and using the stored filtered offset, SINR offsetFILT , the next time the wireless device is being scheduled.

34 . The method as claimed in claim 26 , wherein the determining of a channel covariance matrix, H H H, comprises receiving sounding reference signals or Demodulation Reference Symbols from the wireless device and determining the channel covariance matrix, H H H, based thereon.

35 . The method as claimed in claim 26 , wherein in the approximating of the post-equalizer signal to interference plus noise ratio, SINR appox , the interference plus noise covariance matrix, R, is used.

36 . The method as claimed in claim 26 , wherein the link adaptation parameter is used for determining one or more of: transmission rank, modulation and coding scheme, precoding matrix, allocation size.

37 . The method as claimed in claim 26 , wherein the received signal to interference plus noise ratio, SINR received , is available in the network node or is calculated using the channel matrix, H, and the interference plus noise covariance matrix, R.

38 . A network node for determining a link adaptation parameter, SINR LA,i , for a wireless device, the network node being configured to support a multi-antenna transmission mode comprising spatial multiplexing layers for transmission of data on a channel between the wireless device and the network node, the network node comprising a processor and memory, the memory containing instructions executable by the processor, whereby the network node is operative to:
determi

Assignees

• Ericsson Telefon Ab L M

Inventors

• Sandberg David
• Åhlander Mats

Classifications

• H04L25/0204

  of multiple channels · CPC title

• H04L25/0256

  Channel estimation using minimum mean square error criteria · CPC title

• H04B7/063

  Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection · CPC title

• H04L25/0242

  using matrix methods · CPC title

• H04L1/0026 Primary

  Transmission of channel quality indication · CPC title