Methods and systems for anchored down-selection in a coordinated multipoint transmission cluster

• US 8,837,320 B2
• Filed: 07/22/2013
• Issued: 09/16/2014
• Est. Priority Date: 07/23/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Cili, Gencer
• Primary Examiner(s): HAN, CLEMENCE S
• Application Number:
  US13/948,113
• Publication Number:
  US 20140022925A1
• Time in Patent Office: 421 Days
• Field of Search: None
• US Class Current: 370/252
• 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: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0222 Estimation of channel variability, e.g. coherence bandwidth, coherence time, fading frequency
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

A method to select members of a transmission set in a wireless network including receiving a list of network nodes included in a measurement set provided by a serving node is provided. The method includes determining received measurement values associated with the network nodes included in the measurement set and sorting the determined received measurement values in decreasing order. The method includes selecting transmission set cluster members having a determined received measurement value according to a threshold and providing channel status information (CSI) feedback on a plurality of network nodes included in the transmission set to the serving node in the wireless network.

Claims

1. A method to select members of a transmission set in a wireless network, the method comprising:

receiving a measurement set from a serving node in the wireless network, the measurement set including a list of network nodes;

determining a plurality of measurement values, each measurement value in the plurality of measurement values being associated with a network node in the list of network nodes included in the measurement set;

sorting the plurality of measurement values in decreasing numerical order;

selecting a plurality of network nodes as the members of the transmission set according to the plurality of measurement values associated with the list of network nodes and according to a threshold; and

providing a channel status information (CSI) feedback to the serving node for at least one network node in the plurality of network nodes included in the transmission set.

2. The method of claim 1, wherein determining the plurality of measurement values comprises at least one of a group consisting of determining a received signal power and determining a received signal quality.

3. The method of claim 1, wherein determining the plurality of measurement values comprises smoothing the plurality of measurement values.

4. The method of claim 3, wherein smoothing the plurality of measurement values comprises averaging a subset of the plurality of measurement values over a time window.

5. The method of claim 4, further comprising, determining the time window to have a length less than a coherence time.

6. The method of claim 3, wherein smoothing the plurality of measurement values comprises predicting a value for at least one measurement value in the plurality of measurement values using a set of historical data over a time window.

7. The method of claim 1, wherein selecting the plurality of network nodes as the members of the transmission set comprises:

selecting a particular measurement value in the plurality of measurement values; and

selecting at least one network node in the plurality of network nodes associated with a measurement value within the threshold from the particular measurement value.

8. The method of claim 1, wherein determining the plurality of measurement values comprises determining a set of measurement values associated with a plurality of multipaths linking a single network node with a user equipment.

9. The method of claim 1, further comprising determining the threshold based on a threshold value provided by the serving node and based on a standard deviation of measurement errors associated with the plurality of measurement values.

10. A method to manage downlink data transmission in a wireless network, the method comprising:

receiving in a user equipment, from a serving node in the wireless network, a measurement set of network nodes and one or more measurement identifiers;

receiving a set of reference symbols that includes at least one reference symbol from each network node in the measurement set of network nodes;

providing to the serving node a centralized channel status information (CSI) feedback based on the set of reference symbols received from the measurement set of network nodes;

providing to at least one network node in the measurement set of network nodes a decentralized CSI feedback based on the set of reference symbols received from the measurement set of network nodes; and

receiving a transmission set from the serving node, the transmission set comprising a plurality of network nodes selected from the measurement set of network nodes, the transmission set selected according to the centralized CSI feedback and the decentralized CSI feedback provided by the user equipment.

11. The method of claim 10, further comprising:

determining a first threshold for the centralized CSI feedback; and

determining a second threshold, smaller than the first threshold, for the decentralized CSI feedback.

12. The method of claim 10, wherein the one or more measurement identifiers comprises at least one of a group consisting of a reference signal received power (RSRP) and a reference signal received quality (RSRQ).

13. The method of claim 10, wherein receiving the set of reference symbols comprises receiving at least eight cell specific reference symbols in a sub-frame and receiving at least one reference symbol from each network node in the measurement set of network nodes outside a cell in the sub-frame, wherein the cell is associated with the serving node.

14. The method of claim 10, further comprising decoding a physical downlink shared channel (PDSCH) for at least one network node included in the transmission set.

15. The method of claim 10, further comprising receiving multi-point user plane data from at least two network nodes included in the transmission set.

16. A user equipment for use in a wireless network, the user equipment comprising:

wireless circuitry comprising a receiver and a transmitter;

a memory circuit configured to store data and commands; and

a processor circuit configured to execute the commands stored in the memory circuit, and when executing the commands stored in the memory circuit, the processor circuit;

causes the receiver to receive a first information message from a serving node, the first information message including a list of a plurality of measurement nodes in the wireless network;

performs a plurality of measurements on a set of signals received from the plurality of measurement nodes;

selects a plurality of transmission nodes from the plurality of measurement nodes; and

causes the transmitter to provide a second information message to the serving node, the second information message including a channel status information (CSI) feedback for at least one transmission node in the plurality of transmission nodes.

17. The user equipment of claim 16, wherein the memory circuit further comprises a circular buffer configured to store a set of channel data for at least one measurement node in the plurality of measurement nodes for a preselected time window.

18. The user equipment of claim 17, wherein the processor circuit, when executing the commands stored in the memory circuit, calculates a moving average of the set of channel data stored in the circular buffer.

19. The user equipment of claim 17, wherein the processor circuit, when executing the commands stored in the memory circuit, determines a node clustering degree based on the set of channel data.

20. The user equipment of claim 17, wherein the processor circuit, when executing the commands stored in the memory circuit, determines a history of a measurement node in the plurality of measurement nodes during the preselected time window.