METHOD AND APPARATUS FOR JOINT PROCESSING AND PRECODING MODE SELECTION BASED ON LIMITED FEEDBACK IN MOBILE COMMUNICATION SYSTEM

• US 20120219043A1
• Filed: 02/24/2012
• Published: 08/30/2012
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Industry Academic Cooperation Foundation, Samsung Electronics Co. Ltd.
• Original Assignee: Industry Academic Cooperation Foundation, Samsung Electronics Co. Ltd.
• Inventors: Ko, Eun-Seok, Kim, Yung-Soo, Lee, Sanghoon, Lee, Hojae
• Granted Patent: US 9,385,799 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme

Abstract

According to one embodiment, a method of a base station configured to select a precoding mode in a mobile communication system. When channel estimate information is received from at least one terminal, the channel estimate information is collected, so that user grouping is performed according to one precoding scheme from among multiple precoding schemes. Individual user scheduling is performed according to each precoding scheme, so that a service candidate group set is generated. The selected precoding scheme is maximized according to a transmission capacity of a service candidate group set for each precoding scheme. Data is then transmitted to a determined candidate group set using the determined precoding scheme.

Claims

1. A method for selecting a precoding mode in a mobile communication system by a base station, the method comprising:

when receiving channel estimate information from at least one terminal, collecting the channel estimate information to perform user grouping according to a precoding scheme from among a plurality of precoding schemes;

performing individual user scheduling according to each precoding scheme to generate a service candidate group set;

determining a precoding scheme that maximizes a transmission capacity of a service candidate group set for each precoding scheme; and

transmitting data to a determined candidate group set using the determined precoding scheme.

2. The method of claim 1, further comprising sharing the channel estimate information and the determined precoding scheme with one or more cooperating neighbor base stations via a backhaul network.

3. The method of claim 1, wherein the channel estimate information comprises at least one of a Channel Direction Indicator (CDI), a Channel Quality Indicator (CQI), and information regarding the determined precoding scheme.

4. The method of claim 1, wherein the collecting of the channel estimate information to perform the user grouping according to the precoding scheme further comprises:

collecting terminals that use the same precoding scheme to set respective initial candidate group sets according to the following Equation;

5. The method of claim 1, wherein the performing of the individual user scheduling according to each precoding scheme to generate the service candidate group set further comprises:

performing individual user scheduling according to the precoding scheme to generate a service candidate group set where users up to a specified number of users have been selected.

6. The method of claim 1, wherein the determining of the precoding scheme that maximizes the transmission capacity of the service candidate group set for each precoding scheme further comprises:

determining the precoding scheme using according to the following Equation;

7. A method for selecting a precoding mode in a mobile communication system by a terminal, the method comprising:

performing channel estimation on a reference signal received from a base station to select a precoding scheme from among a plurality of precoding schemes;

feeding back channel information regarding the selected precoding scheme to the base station; and

receiving data from the base station according to the selected precoding scheme.

8. The method of claim 7, wherein the performing of the channel estimation comprises:

selecting a Channel Direction Indicator (CDI) according to each precoding scheme and determining a corresponding Channel Quality Indicator (CQI) according to the following Equation;

9. The method of claim 7, wherein the selecting of the precoding scheme comprises:

selecting a precoding scheme maximizing a CQI according to the following Equation;

10. The method of claim 7, wherein the channel information regarding the determined precoding scheme comprises at least one of a Channel Direction Indicator (CDI), a Channel Quality Indicator (CQI), and information regarding the selected precoding scheme.

11. A base station configured to select a precoding mode in a mobile communication system, the base station comprising:

a user grouping unit configured to, when receiving channel estimate information from at least one terminal, collect the channel estimate information to perform user grouping according to a precoding scheme from among a plurality of precoding schemes;

a scheduler configured to perform individual user scheduling according to each precoding scheme to generate a service candidate group set, and determine a precoding scheme that maximizes a transmission capacity of a service candidate group set for each precoding scheme; and

a transmitter configured to transmit data to a determined candidate group set using the determined precoding scheme.

12. The apparatus of claim 11, wherein the scheduler shares the channel estimate information and the determined precoding scheme with cooperating neighbor base stations via a backhaul network.

13. The apparatus of claim 11, wherein the channel estimate information comprises at least one of a Channel Direction Indicator (CDI), a Channel Quality Indicator (CQI), and information regarding the determined precoding scheme.

14. The apparatus of claim 11, wherein when collecting the channel estimate information to perform the user grouping according to the precoding scheme, the user grouping unit is configured to collect terminals that use the same precoding scheme to set respective initial candidate group sets according to the following Equation:

15. The apparatus of claim 11, wherein when performing the individual user scheduling according to each precoding scheme to generate the service candidate group set, the scheduler is configured to perform individual user scheduling according to the determined precoding scheme to generate the service candidate group set where users up to a specified number of users have been selected.

16. The apparatus of claim 11, wherein when determining the precoding scheme maximizing the transmission capacity of the service candidate group set for each precoding scheme, the scheduler is configured to determine the precoding scheme according to the following Equation:

17. A terminal configured to select a precoding mode in a mobile communication system, the terminal comprising:

a receiver configured to perform channel estimation on a reference signal received from a base station, and receive data from the base station according to a determined precoding scheme;

a mode selector configured to select a precoding scheme according to a channel estimate result; and

a transmitter configured to feed back channel information regarding the determined precoding scheme to the base station.

18. The apparatus of claim 17, wherein when performing the channel estimation, the receiver is configured to select a Channel Direction Indicator (CDI) according to each precoding scheme and determine a corresponding Channel Quality Indicator (CQI) according to the following Equation:

19. The apparatus of claim 17, wherein when selecting the precoding scheme, the mode selector is configured to select a precoding scheme that maximizes a CQI according to the following Equation:

20. The apparatus of claim 17, wherein the channel information regarding the determined precoding scheme comprises at least one of a Channel Direction Indicator (CDI), a Channel Quality Indicator (CQI), and information regarding the determined precoding scheme.