METHOD AND APPARATUS FOR INTERFERENCE MITIGATION VIA SUCCESSIVE CANCELLATION IN HETEROGENEOUS NETWORKS

• US 20140146756A1
• Filed: 11/10/2011
• Published: 05/29/2014
• Est. Priority Date: 11/10/2010
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Sahin, Onur, Li, Jialing, Pietraski, Philip, Li, Yingxue
• Granted Patent: US 9,319,197 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861

Abstract

Techniques for inter-cell interference cancellation are disclosed. At each transmitter, the data (message) may split into two or more layers, (e.g., common and private parts), and may be encoded in different rates, allocated with different powers, possibly beamformed using different precoders, and transmitted through the same physical channels. The common part is to be decoded at both the intended and unintended users, while the private part is to be decoded at the intended user.

Claims

1. A method comprising:

obtaining, at a WTRU, demodulation information associated with a private part, a first common part and a second common part;

processing a received signal, according to the demodulation information, including at least the first common part, the second common part, and the private part; and

,

transmitting a multipart hybrid automatic repeat request (HARQ) message indicating a combination of acknowledgements and/or non-acknowledgements (ACK/NACK) for the first common part, second common part, and private part.

2. The method of claim 1 wherein the demodulation information includes Modulation and Coding Scheme (MCS) information.

3. The method of claim 2 wherein the MCS information for the first common part is obtained from a Physical Downlink Control Channel (PDCCH) of a first eNodeB and the MCS for the second common part is obtained from a PDCCH of a second eNodeB.

4. The method of claim 1 wherein the MCS information is obtained from demodulation reference symbols (DM-RS).

5. The method of claim 1 wherein the demodulation information includes precoder information.

6. The method of claim 1 wherein the demodulation information includes power allocations.

7. The method of claim 1 further comprising transmitting a Successive Interference Cancellation (SIC) indicator message.

8. The method of claim 1 further comprising processing a signal retransmitted in response to the multipart HARQ message, using successive interference cancellation.

9. A method comprising:

obtaining at a first eNodeB a plurality of transmit spatial covariance matrices associated with a respective plurality of WTRUs, including receiving covariance information associated with at least one transmit spatial covariance matrix via an X2 interface from a second eNodeB;

determining common and private message splitting rates based on the plurality of covariance matrices;

determining common and private precoder weights based on the transmit spatial covariance matrices; and

,

transmitting a common and a private message parts using the common and private message splitting rates, respectively, and the common and private precoder weights, respectively.

10. The method of claim 9 wherein the covariance information associated with at least one transmit spatial covariance matrix is used to generate an estimate of a corresponding transmit spatial covariance matrix.

11. The method of claim 10 wherein the estimate is based on one or more of RI, PMI, and CQI.

12. An apparatus comprising:

a WTRU including a processor, configured to;

obtain demodulation information associated with a private part, a first common part and a second common part;

process a received signal, according to the demodulation information, including at least the first common part, the second common part, and the private part; and

,

control a HARQ process and generate a multipart HARQ message indicating a combination of acknowledgements and/or non-acknowledgements (ACK/NACK) for the first common part, second common part, and private part; and

,

a transceiver configured to transmit the multipart HARQ message.

13. The apparatus of claim 12 wherein the WTRU is configured to obtain Modulation and Coding Scheme (MCS) information for the first common part from a Physical Downlink Control Channel (PDCCH) of a first eNodeB, and to obtain MCS information for the second common part from a PDCCH of a second eNodeB.

14. The apparatus of claim 12 wherein the WTRU is configured to obtain the MCS information from demodulation reference symbols (DM-RS).

15. The apparatus of claim 12 wherein the demodulation information includes one of precoder information or power allocations.

16. The apparatus of claim 12 wherein the WTRU is further configured to transmit a Successive Interference Cancellation (SIC) indicator message.