ANTENNA COMBINING FOR MASSIVE MIMO SCHEME

• US 20160173252A1
• Filed: 02/21/2014
• Published: 06/16/2016
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: LEE, Kilbom, KANG, Jiwon, KO, Hyunsoo, CHUNG, Jaehoon
• Granted Patent: US 9,900,135 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G07F 11/38 in which the magazines are horizontal
• CPC Class Codes: G07F 11/50 the storage containers or supports being rotatably mounted
• 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 7/0404 the mobile station comprising multiple antennas, e.g. to provide uplink diversity
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0482 Adaptive codebooks
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

The base station, receiving first pilot signals transmitted via each of multiple antennas of a user equipment (UE), selects one or more reference codebooks based on channel qualities of the received first pilot signals, and selects one or more sub-channels for each of the reference codebooks. Based on this, the base station determines one or more virtual channels, wherein each of the virtual channels comprises one reference codebook and the one or more sub channels selected for the one reference codebook, wherein the sub-channels are selected to minimum distance between corresponding virtual channel and corresponding reference codebook. And, the base station transmits antenna combining information to the UE, wherein the antenna combining information combines the multiple antennas of the UE into one or more antenna groups corresponding to the one or more virtual channels; and receive second pilot signals transmitted by the UE based on the antenna combining information.

Claims

1. A method for a base station to operate in a wireless communication system employing a massive MIMO (Multiple Input Multiple Output) scheme, the method comprising:

receiving first pilot signals transmitted via each of multiple antennas of a user equipment (UE);

selecting one or more reference codebooks based on channel qualities of the received first pilot signals;

selecting one or more sub-channels for each of the reference codebooks;

determining one or more virtual channels, wherein each of the virtual channels comprises one reference codebook among the one or more reference codebooks and the one or more sub channels selected for the one reference codebook, wherein the sub-channels are selected to minimum distance between corresponding virtual channel and corresponding reference codebook;

transmitting antenna combining information to the UE, wherein the antenna combining information combines the multiple antennas of the UE into one or more antenna groups corresponding to the one or more virtual channels; and

receiving second pilot signals transmitted by the UE based on the antenna combining information.

2. The method of claim 1, wherein each of orthogonal sequences for pilot signals is allocated to each of the antenna groups, and

wherein the second pilot signals were generated by using the allocated orthogonal sequences for each of the antenna groups.

3. The method of claim 1, wherein said selecting the one or more reference codebooks comprises:

selecting one or more reference channels based on reception power of each channel from each of the multiple antennas; and

selecting each of the reference codebooks as closest to each of the reference channels.

4. The method of claim 1, further comprising:

estimating distance between virtual channels based on the received second pilot signals; and

transmitting a request message to the UE requesting to retransmit the first pilot signals when the correlation value becomes larger than a threshold value.

5. The method of claim 4, further comprising:

transmitting modified antenna combining information to the UE determined based on the retransmitted first pilot signals.

6. The method of claim 1, further comprising:

estimating downlink channel from the base station to the UE based on the received second pilot signals.

7. The method of claim 1, wherein the UE is within a first UE group, and

wherein the base station receives the second pilot signals from the UE at different time period other than a time period where the base station receives the second pilot signals from a UE of a second UE group.

8. The method of claim 1, wherein the base station comprises multiple antennas, wherein a number of multiple antennas is greater than a threshold number.

9. A base station operating in a wireless communication system employing a massive MIMO (Multiple Input Multiple Output) scheme, the base station comprising:

multiple antennas;

a transceiver configured to transmit and receive signals via the multiple antennas; and

a processor being connected to and controlling the transceiver,

wherein the processor is configured to receive first pilot signals transmitted via each of multiple antennas of a user equipment (UE);

determine one or more reference codebooks based on channel qualities of the received first pilot signals;

select one or more sub-channels for each of the reference channels;

determine one or more virtual channels, wherein each of the virtual channels comprises one reference codebook among the one or more reference codebooks and the one or more sub channels selected for the one reference codebook, wherein the sub-channels are selected to minimum distance between corresponding virtual channel and corresponding reference codebook;

transmit antenna combining information to the UE, wherein the antenna combining information combines the multiple antennas of the UE into one or more antenna groups corresponding to the one or more virtual channels; and

receive second pilot signals transmitted by the UE based on the antenna combining information.

10. The base station of claim 9, wherein each of orthogonal sequences for pilot signals is allocated to each of the antenna groups, and

wherein the second pilot signals were generated by using the allocated orthogonal sequences for each of the antenna groups.

11. The base station of claim 9, wherein the processor is further configured to select one or more reference channels based on reception power of each channel from each of the multiple antennas;

and select each of the reference codebooks as closest to each of the reference channels.

12. The base station of claim 9, wherein the processor is further configured to:

estimate distance between virtual channels based on the received second pilot signals; and

transmit a request message to the UE requesting to retransmit the first pilot signals when the correlation value becomes larger than a threshold value.

13. The base station of claim 12, wherein the processor is further configured to:

transmit modified antenna combining information to the UE determined based on the retransmitted first pilot signals.

14. The base station of claim 9, wherein the processor is further configured to:

estimate downlink channel from the base station to the UE based on the received second pilot signals.

15. The base station of claim 9, wherein the UE is within a first UE group, and

wherein the base station receives the second pilot signals from the UE at different time period other than a time period where the base station receives the second pilot signals from a UE of a second UE group.