TRANSMIT POWER ALLOCATION FOR ADAPTIVE MULTI-CARRIER MULTIPLEXING MIMO SYSTEMS

• US 20090161784A1
• Filed: 11/21/2008
• Published: 06/25/2009
• Est. Priority Date: 12/20/2007
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: STADELMEIER, Lothar, Schneider, Daniel
• Granted Patent: US 9,042,310 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0426 Power distribution
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 76/00 Connection management
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

The present invention relates to transmit power allocation in multi-carrier, multiplexing MIMO communication systems. The present invention especially relates to a MIMO communication device, a method of assigning transmit power to two or more communication channels and a software program product. A multiple-input-multiple-output, MIMO, communication device according to the present invention comprises

a link controller adapted to assign transmit power to two or more transmission channels, each of said transmission channels having preassigned a portion of transmit power for each of a group of subcarriers, said link controller being further adapted to assign, for each subcarrier of said group of subcarriers, at least part of the preassigned transmit power portion of a transmission channel that is not used for transmitting information at the subcarrier, to one or more transmission channels that are used for transmitting information at the subcarrier.

Claims

1. A multiple-input-multiple-output, MIMO, communication device (1) comprising

a link controller (4) adapted to assign transmit power to two or more transmission channels, each of said transmission channels having preassigned a portion of transmit power for each of a group of subcarriers,

said link controller (4) being further adapted to assign, for each subcarrier of said group of subcarriers, at least part of the preassigned transmit power portion of a transmission channel that is not used for transmitting information at the subcarrier, to one or more transmission channels that are used for transmitting information at the subcarrier.

2. A MIMO communication device (1-2) according to claim 1 comprising

a multiplexing MIMO detector (22), whereby said transmission channels correspond to output ports of the multiplexing MIMO detector.

3. A MIMO communication device (1-2) according to claim 1 or 2 wherein said link controller (4-2) is adapted to

determine an indicator value of a signal-to-noise ratio, SNR, for each subcarrier of said group of subcarriers on each transmission channel and to

determine, for each transmission channel and each subcarrier of said group of subcarriers, if the transmission channel is used for transmitting data at the subcarrier based on the corresponding indicator value of the SNR.

4. A MIMO communication device (1-2) according to claim 3 wherein said link controller (4-2) is adapted to

determine for at least one subcarrier on at least one transmission channel an indicator value of an expected SNR, said indicator value of the expected SNR being based on the corresponding indicator value of the SNR and the corresponding assigned transmit power.

5. A MIMO communication device (1-2) according to claim 4 comprising

a symbol demapper unit (24) for demodulating received symbols,

whereby the link controller (4-2) is adapted

to determine a demodulation scheme for each of said at least one subcarrier on said at least one transmission channel based on the corresponding indicator value of the expected SNR and

to configure said symbol demapper unit (24) with the determined demodulation schemes so that a symbol transmitted on a given one of said at least one subcarrier on said at least one transmission channel is demodulated with the corresponding determined demodulation scheme.

6. A MIMO communication device (1-1) according to claim 1 comprising

a multiplexing MIMO precoder (14), whereby said transmission channels correspond to input ports of the multiplexing MIMO precoder (14).

7. A MIMO communication device (1-1) according to claim 1 or 6 comprising a receiving unit (3-1) adapted to receive notching information indicating which transmission channels are not used for transmitting information at which subcarriers, whereby the link controller (4-1) is adapted to determine which transmission channels are not used to transmit information at which subcarriers based on the received notching information.

8. A MIMO communication device (1) according to claim 1, wherein at least some of said transmission channels have preassigned the same transmit power portions for a given subcarrier of said group of subcarriers.

9. A MIMO communication device (1) according to claim 1, wherein at least some subcarriers of said group of subcarriers have preassigned the same transmit power portions for a given transmission channel.

10. A method of assigning transmit power to two or more communication channels, each of said communication channels having preassigned a portion of transmit power for each of a group of subcarriers, the method comprising a step of

assigning (S34, S46), for each subcarrier of said group of subcarriers, at least part of the preassigned transmit power portion of a transmission channel that is not used for transmitting information at the subcarrier, to one or more transmission channels that are used for transmitting information at the subcarrier.

11. A method according to claim 10 wherein said communication channels correspond to input ports of a multiplexing MIMO precoder (14) and/or output ports of a multiplexing MIMO detector (22).

12. A method according to claim 10 or 11 further comprising steps of

determining (S30) an indicator value of a signal-to-noise ratio, SNR, for each subcarrier of said group of subcarriers on each transmission channel, and

determining (S32), for each transmission channel and each subcarrier of said group of subcarriers, if the transmission channel is used for transmitting data at the subcarrier based on the corresponding indicator value of the SNR.

13. A method according to claim 12 further comprising

determining (S36) for at least one subcarrier on at least one transmission channel an indicator value of an expected SNR, said indicator value of the expected SNR being based on the corresponding indicator value of the SNR and the corresponding assigned transmit power.

14. A method according to claim 13 further comprising

determining (S38) a modulation scheme for each of said at least one subcarrier on said at least one transmission channel based on the corresponding indicator value of the expected SNR and

modulating each given one of said at least one subcarrier on said at least one transmission channel with the corresponding determined modulation scheme.

15. A method according to claim 10, wherein at least some of said transmission channels have preassigned the same transmit power portions for a given subcarrier of said group of subcarriers.

16. A method according to claim 10, wherein at least some subcarriers of said group of subcarriers have preassigned the same transmit power portions for a given transmission channel.

17. A software program product which, when executed by one or more processing device, is adapted to carry out the method according to claim 10.