Method for transmitting extra spatial layers over the wireless channel

Patent metadata

Field	Value
Publication number	US-9450658-B1
Application number	US-201514819657-A
Country	US
Kind code	B1
Filing date	Aug 6, 2015
Priority date	Aug 6, 2015
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A method of transmitting extra spatial layers over a wireless channel is proposed. In one exemplary embodiment, the invention is directed to a method for scheduling higher number of layers than the preferred number reported from a mobile. In one exemplary embodiment, the invention is directed to a method for reporting multiple precoding candidates for the rank that is higher than the preferred rank reported from a mobile. In one exemplary embodiment, the invention is directed to a method for appending extra columns in the precoding matrix for the extra layers that a base station transmits. In one exemplary embodiment, the invention is directed to a method for transmitting extra data streams on the same wireless channel. In one exemplary embodiment, the invention is directed to a method for saving battery power utilizing the extra layers.

First claim

What is claimed is:

1. A method comprising:
(a) receiving channel state information (CSI) from a user equipment (UE) by a base station in a mobile communication network, wherein the CSI comprises a rank indicator indicating a channel rank and a precoding matrix indicator indicating an original precoding matrix;
(b) determining a number of spatial layers that is more than the channel rank;
(c) appending additional precoding vectors in the original precoding matrix to form a new precoding matrix; and
(d) transmitting data over the spatial layers using the new precoding matrix.

2. The method of claim 1 , wherein the additional precoding vectors are determined to substantially minimize inter-layer interference among the spatial layers.

3. The method of claim 1 , wherein the base station determines the additional precoding vectors based on an additional precoding matrix indicator for a higher channel rank transmitted by the UE.

4. The method of claim 1 , wherein each column of the new precoding matrix is applied with a corresponding power factor to reduce inter-layer interference.

5. The method of claim 1 , wherein the data comprises an original data portion corresponds to the original precoding matrix and a new data portion corresponds to the additional precoding vectors.

6. The method of claim 5 , wherein the new data portion is applied with a lower order of modulation than the original data portion.

7. The method of claim 5 , wherein both the original data portion and the new data portion are applied with a low order of modulation to reduce inter-layer interference among the spatial layers.

8. A method comprising:
(a) estimating channel state information (CSI) by a user equipment (UE) in a mobile communication network, wherein the CSI comprises a rank indicator indicating a channel rank and a precoding matrix indicator (PMI) indicating an original precoding matrix;
(b) transmitting the CSI as feedback information to a base station;
(c) receiving data over a number of spatial layers that is more than the channel rank, wherein the data is precoded by the base station with a new precoding matrix having additional precoding vectors; and
(d) decoding the data over the spatial layers using an advanced receiver that cancels inter-layer interference among the spatial layers.

9. The method of claim 8 , wherein the UE also feedbacks additional recommended PMIs for determining the additional precoding vectors.

10. The method of claim 8 , wherein each of the additional precoding vectors is applied with a corresponding power factor to reduce inter-layer interference.

11. The method of claim 8 , wherein each column of the original precoding matrix is applied with a corresponding power factor to reduce inter-layer interference.

12. The method of claim 8 , wherein the data comprises an original data portion corresponds to the original precoding matrix and a new data portion corresponds to the additional precoding vectors.

13. The method of claim 12 , wherein the new data portion is applied with a lower order of modulation than the original data portion.

14. The method of claim 12 , wherein both the original data portion and the new data portion are applied with a low order of modulation to reduce inter-layer interference among the spatial layers.

15. A user equipment, comprising:
a channel estimation module that estimates channel state information (CSI) in a mobile communication network, wherein the CSI comprises a rank indicator indicating a channel rank and a precoding matrix indicator indicating an original precoding matrix;
a transmitter that transmits the CSI as feedback information to a base station; and
an advanced receiver that receives data over a number of spatial layers that is more than the channel rank, wherein the data is precoded by the base station with a new precoding matrix having additional precoding vectors, and wherein the data is decoded by the receiver over the spatial layers that cancels inter-layer interference among the spatial layers.

16. The UE of claim 15 , wherein the UE also feedbacks additional recommended PMIs for determining the additional precoding vectors.

17. The UE of claim 15 , wherein each of the additional precoding vectors is applied with a corresponding power factor to reduce inter-layer interference.

18. The UE of claim 15 , wherein each column of the original precoding matrix is applied with a corresponding power factor to reduce inter-layer interference.

19. The UE of claim 15 , wherein the data comprises an original data portion corresponds to the original precoding matrix and a new data portion corresponds to the additional precoding vectors.

20. The UE of claim 19 , wherein the new data portion is applied with a lower order of modulation than the original data portion.

21. The UE of claim 19 , wherein both the original data portion and the new data portion are applied with a low order of modulation to reduce inter-layer interference among the spatial layers.

Assignees

• Mediatek Inc

Inventors

• Moon Jangwook
• Low Tze-Ping

Classifications

• H04B7/0417

  Feedback systems · CPC title

• H04B7/0639

  Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection · CPC title

• H04B7/0413 Primary

  MIMO systems · CPC title

• H04B7/0626

  Channel coefficients, e.g. channel state information [CSI] · CPC title

• H04L1/0026

  Transmission of channel quality indication · CPC title