COMMUNICATION APPARATUS AND PRECODING METHOD BASED ON MULTIPLE CELLS AND MULTIPLE USERS

• US 20110177834A1
• Filed: 11/02/2010
• Published: 07/21/2011
• Est. Priority Date: 01/18/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jang, Kyung Hun, Hong, Young Jun, Shin, Chang Yong, Lee, Nam Yoon, Shin, Won Jae
• Granted Patent: US 9,231,795 B2
• Time in Patent Office: Days
• US Class Current: 455/501
• CPC Class Codes: H04J 11/0033 by pre-cancellation of known interference, e.g. using a matched filter, dirty paper coder or Thomlinson-Harashima precoder correlative coding in synchronous or start-stop systems H04L25/497
• CPC Class Codes: H04J 11/0059 Out-of-cell user aspects
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

Provided are a communication apparatus that may generate a precoding matrix including precoding vectors to cancel or align interference existing in a plurality of terminal devices based on location of the terminal devices, and a terminal device that may estimate a channel formed between the terminal device and the communication apparatus to cancel or align interference signals.

Claims

1. A precoding method, comprising:

aligning, in the same space, interference channels of one or more terminal devices included in a cell edge region of an interference base station; and

generating a reception beamforming vector of one or more terminal devices included in a cell edge region of a serving base station, based on the interference channels of the interference base station that are aligned in the same space.

2. The precoding method of claim 1, further comprising:

generating a precoding vector of the one or more terminal devices included in the cell edge region of the serving base station, based on a basis vector of each of the interference channels of the interference base station that are aligned in the same space, and an interference channel of the serving base station.

3. The precoding method of claim 2, further comprising:

transmitting, to the one or more terminal devices included in the cell edge region of the serving base station, at least one of the reception beamforming vector and data that is precoded using the generated precoding vector.

4. The precoding method of claim 1, wherein the aligning comprises aligning, in the same space, the interference channels of the one or more terminal devices included in the cell edge region of the interference base station to be partially overlapped with each other.

5. A communication apparatus, comprising:

an interference channel alignment unit to align, in the same space, interference channels of one or more terminal devices included in a cell edge region of an interference base station; and

a reception beamforming vector generator to generate a reception beamforming vector of one or more terminal devices included in a cell edge region of a serving base station, based on the interference channels of the interference base station that are aligned in the same space.

6. The communication apparatus of claim 5, further comprising:

a precoder to generate a precoding vector of the one or more terminal devices included in the cell edge region of the serving base station, based on a basis vector of each of the interference channels of the interference base station that are aligned in the same space, and an interference channel of the serving base station.

7. The communication apparatus of claim 6, wherein the precoder transmits, to the one or more terminal devices included in the cell edge region of the serving base station, at least one of the reception beamforming vector and data that are precoded using the generated precoding vector.

8. The communication apparatus of claim 5, wherein the interference channel alignment unit aligns, in the same space, the interference channels of the one or more terminal devices included in the cell edge region of the interference base station to be partially overlapped with each other.

9. A method of generating a reception beamforming, comprising:

obtaining interference channels of one or more terminal devices included in a cell edge region of an interference base station;

aligning the obtained interference channels in the same space; and

generating a reception beamforming vector of one or more terminal devices included in a cell edge region of a serving base station, based on the interference channels of the interference base station that are aligned in the same space.

10. The method of claim 9, further comprising:

feeding back, to the serving base station, at least one of the aligned interference channels and a serving channel.

11. The method of claim 9, wherein the aligning comprises aligning, in the same space, the interference channels of the one or more terminal devices included in the cell edge region of the interference base station to be partially overlapped with each other.

12. A terminal device, comprising:

an interference channel obtainment unit to obtain interference channels of one or more terminal devices included in a cell edge region of an interference base station;

an interference channel alignment unit to align the obtained interference channels in the same space; and

a reception beamforming vector generator to generate a reception beamforming vector of one or more terminal devices included in a cell edge region of a serving base station, based on the interference channels of the interference base station that are aligned in the same space.

13. The terminal device of claim 12, further comprising:

a feedback unit to feed back, to the serving base station, at least one of the aligned interference channels and a serving channel.

14. The terminal device of claim 12, wherein the interference channel alignment unit aligns, in the same space, the interference channels of the one or more terminal devices included in the cell edge region of the interference base station to be partially overlapped with each other.

15. A precoding method, comprising:

calculating a zero-forcing precoding vector to process interference occurring between a plurality of terminal devices served by a serving base station;

calculating an interference alignment precoding vector to align interference caused by a plurality of neighboring base stations located adjacent to the serving base station and interference occurring between the plurality of terminal devices served by the serving base station;

generating a precoding matrix based on the zero-forcing precoding vector and the interference alignment precoding vector; and

precoding data based on the generated precoding matrix.

16. The precoding method of claim 15, further comprising:

determining whether each of the plurality of terminal devices is located in a cell interior region or a cell edge region,

wherein a terminal device located in the cell edge region and a terminal device located in the cell interior region use the same frequency band.

17. The precoding method of claim 16, wherein:

the calculating of the zero-forcing precoding vector comprises calculating the zero-forcing precoding vector when at least one terminal device from among the plurality of terminal devices is located in the cell interior region, and

at least two signals are transmitted to the at least one terminal device located in the cell interior region.

18. The precoding method of claim 16, wherein the calculating of the interference alignment precoding vector comprises calculating the interference alignment precoding vector when at least one terminal device from among the plurality of terminal devices is located in the cell edge region.

19. The precoding method of claim 16, wherein the determining comprises determining whether each of the plurality of terminal devices is located in the cell interior region or the cell edge region based on location information of the plurality of terminal devices or a signal-to-interference plus noise ratio (SINR) of each of the plurality of terminal devices.

20. The precoding method of claim 16, further comprising:

selecting at least one terminal device from a plurality of terminal devices located in the cell edge region of each of the serving base station and the plurality of neighboring base stations, and selecting at least one terminal device from a plurality of terminal devices located in cell interior regions of each of the serving base station and the plurality of neighboring base stations,

wherein the generating comprises generating the precoding matrix based on at least two zero-forcing precoding vectors that are calculated with respect to the selected at least one terminal device located in the cell interior region.

21. The precoding method of claim 20, wherein:

when the selected at least one terminal device is located in the cell edge region of each of the serving base station and the plurality of neighboring base stations, the method further comprises selecting, from a plurality of terminal devices located in the cell interior region of the serving base station, at least one terminal device either to increase a sum of throughputs of selected terminal devices located in the cell edge region or to increase a throughput of a terminal device having a minimum throughput from among the selected terminal devices located in the cell edge region.

22. The precoding method of claim 16, further comprising:

selecting, from a plurality of terminal devices located in the cell interior region of the serving base station, at least one terminal device to increase throughputs of terminal devices located in the cell edge region of each of the serving base station and the plurality of neighboring base stations,

wherein the generating comprises generating the precoding matrix based on at least two zero-forcing precoding vectors that are calculated with respect to the selected at least one terminal device.

23. The precoding method of claim 20, wherein:

when selected at least one terminal device is located in the cell edge region of each of the serving base station and the plurality of neighboring base stations, the method further comprises selecting, from a plurality of terminal devices located in the cell interior region of the serving base station, a plurality of terminal devices enabling throughputs of selected terminal devices located in the cell edge region to be greater than or equal to a predetermined reference value; and

selecting a terminal device having a greater throughput from the selected plurality of terminal devices located in the cell interior region.

24. The precoding method of claim 16, further comprising:

selecting, from a plurality of terminal devices located in the cell interior region of the serving base station, a terminal device to increase a sum of throughputs of the terminal devices,

wherein the generating comprises generating the precoding matrix based on at least two zero-forcing precoding vectors that are calculated with respect to the selected terminal device.

25. A communication apparatus, comprising:

a calculator to calculate a zero-forcing precoding vector to process interference occurring between a plurality of terminal devices served by a serving base station, and to calculate an interference alignment precoding vector to align interference caused by a plurality of neighboring base stations located adjacent to the serving base station and interference occurring between the plurality of terminal devices served by the serving base stations;

a generator to generate a precoding matrix based on the zero-forcing precoding vector and the interference alignment precoding vector; and

a precoder to precode data based on the generated precoding matrix.

26. The communication apparatus of claim 25, further comprising:

a decision unit to determine whether each of the plurality of terminal devices is located in a cell interior region or a cell edge region,

wherein a terminal device located in the cell edge region and a terminal device located in the cell interior region use the same frequency band.

27. The communication apparatus of claim 26, wherein the decision unit determines whether each of the plurality of terminal devices is located in the cell interior region or the cell edge region based on location information of each of the plurality of terminal devices or an SINR of each of the plurality of terminal devices.

28. The communication apparatus of claim 26, wherein:

the calculator calculates the zero-forcing precoding vector when at least one terminal device from among the plurality of terminal devices is located in the cell interior region, and

at least two signals are transmitted to the at least one terminal device located in the cell interior region.

29. The communication apparatus of claim 26, wherein the calculator calculates the interference alignment precoding vector when at least one terminal device from among the plurality of terminal devices is located in the cell edge region.

30. The communication apparatus of claim 26, further comprising:

a selector to select, from a plurality of terminal devices located in the cell interior region of the serving base station, at least one terminal device either to increase a sum of throughputs of selected terminal devices located in the cell edge region or to increase a throughput of a terminal device having a minimum throughput from among the selected terminal devices located in the cell edge region, when at least one terminal device is selected from a plurality of terminal devices located in the cell edge region of each of the serving base station and the plurality of neighboring base stations,

wherein the generator generates the precoding matrix based on at least two zero-forcing precoding vectors that are calculated with respect to the selected at least one terminal device.

31. A terminal device, comprising:

a decoding matrix generator to extract channel information from precoded data received from a serving base station, and to generate a decoding matrix based on the extracted channel information; and

a decoder to decode the precoded data based on the generated decoding matrix,

wherein a precoding matrix included in the channel matrix includes a zero-forcing precoding vector and an interference alignment precoding vector.

32. The terminal device of claim 31, wherein the decoding matrix generator generates the decoding matrix including a zero-forcing decoding vector and an interference alignment decoding vector based on the channel information, or generates the decoding matrix using a minimum mean square error (MMSE) estimation scheme.

33. The terminal device of claim 32, wherein:

the zero-forcing decoding vector is used to reduce interference between the terminal device and a plurality of neighboring terminal devices of the serving base station, and

the interference alignment decoding vector is used to align a desired signal received from the serving base station in a first space and interference signals caused by the plurality of neighboring terminal devices of the serving base station and a plurality of neighboring base stations in a different space.

34. The terminal device of claim 33, wherein the zero-forcing decoding vector and the interference alignment decoding vector are orthogonal to the interference signals.