METHODS FOR OPERATING WIRELESS ELECTRONIC DEVICES IN COORDINATED MULTIPOINT TRANSMISSION NETWORKS

• US 20130142054A1
• Filed: 12/02/2011
• Published: 06/06/2013
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Ahmadi, Sassan
• Granted Patent: US 9,270,346 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 17/318 Received signal strength
• 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 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0814 based on current reception conditions, e.g. switching to different antenna when signal level is below threshold
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

A coordinated multipoint (CoMP) transmission radio network is provided. Each cell in the CoMP network may include antenna nodes distributed at different geographical locations and coupled to a common baseband processing unit via an optical fiber link. When operating a user device in the CoMP network, the device may register with a neighboring baseband unit and may be served using at least one antenna node. The device may continuously receive reference signals from different antenna nodes in its vicinity and compute receive signal strength levels. The device may report the measurements to the corresponding baseband unit. The baseband unit may then switch appropriate antennas in/out of use based on the measured results. If desired, the device may be served using more than one antenna node that may or may not be part of the same cell (e.g., the device may be served using antenna nodes coupled to different baseband units).

Claims

1. A method of operating a wireless electronic device in a radio communications network having at least first and second geographically separated antenna nodes that are coupled to a base station, the method comprising:

receiving radio-frequency reference signals from the first and second antenna nodes;

evaluating the received reference signals to obtain evaluation results; and

reporting the evaluation results to the base station.

2. The method defined in claim 1 further comprising:

in response to report the evaluation results to the base station, establishing an uplink communications path with the base station via a selected one of the first and second antenna nodes.

3. The method defined in claim 1 further comprising:

in response to report the evaluation results to the base station, establishing an uplink communications path with the base station via both the first and second antenna nodes based on the reported evaluation results.

4. The method defined in claim 1 wherein evaluating the received reference signals comprises performing radio-frequency measurements on the received reference signals and wherein the radio-frequency measurements comprise measurements selected from the group consisting of:

reference signal receive power, receive signal strength indictor, receive signal code power, signal-to-noise radio, and signal-to-interference ratio.

5. The method defined in claim 1 wherein evaluating the received reference signals comprises obtaining a first signal strength value for the reference signal associated with the first antenna node and obtaining a second signal strength value for the reference signal associated with the second antenna node and wherein the first signal strength value exceeds the second signal strength value, the method further comprising:

in response to reporting the first and second signal strength values to the base station, establishing a first uplink communications path with the base station via the first antenna node.

6. The method defined in claim 5 further comprising:

in response to the first signal strength value falling below a predetermined threshold and to the second signal strength value being greater than the predetermined threshold, terminating the first uplink communications path and establishing a second uplink communications path with the base station via the second antenna node.

7. The method defined in claim 1 wherein each of the first and second antenna nodes comprises at least two antennas and associated radio-frequency front-end circuitry and wherein the first and second antenna nodes lack baseband processing capabilities.

8. The method defined in claim 1 wherein the wireless electronic device comprises a wireless electronic device having multiple antennas.

9. A method of operating a wireless electronic device in a radio communications network having at least a first group of geographically separated antenna nodes that are coupled to a first base station and a second group of geographically separated antenna nodes that are coupled to a second base station, the method comprising:

while at a location within range of the first and second group of antenna nodes, establishing a first uplink communications path with the first base station via at least a first antenna node in the first group of antenna nodes and establishing a second uplink communications path with the second base station via at least a second antenna node in the second group of antenna nodes.

10. The method defined in claim 9 further comprising:

receiving first reference signals from at least the first antenna node in the first group of antenna nodes; and

receiving second reference signals from at least the second antenna node in the second group of antenna nodes.

11. The method defined in claim 10 further comprising:

evaluating the first and second reference signals to obtain evaluation results.

12. The method defined in claim 11 wherein evaluating the first and second reference signals comprises performing radio-frequency measurements on the first and second reference signals and wherein the radio-frequency measurements comprise measurements selected from the group consisting of:

reference signal receive power, receive signal strength indictor, receive signal code power, signal-to-noise radio, and signal-to-interference ratio.

13. The method defined in claim 11 further comprising:

reporting the evaluation results to at least one of the first and second base stations via at least one of the antenna nodes in the first and second groups of antenna nodes.

14. The method defined in claim 10 further comprising:

obtaining first receive signal strength measurements on the first reference signals; and

in response to the first signal strength measurements falling below a predetermined threshold, terminating the first uplink communications path.

15. The method defined in claim 14 further comprising:

receiving third reference signals from at least a third antenna node in the first group of antenna nodes;

obtaining third signal strength measurements on the third reference signal; and

in response to the third signal strength measurements satisfying performance criteria, establishing a third uplink communications path with the first base station via the third antenna node.

16. The method defined in claim 14 further comprising:

receiving third reference signals from at least a third antenna node in the second group of antenna nodes;

obtaining third signal strength measurements on the third reference signal; and

in response to the third signal strength measurements satisfying performance criteria, establishing a third uplink communications path with the second base station via the third antenna node.

17. A method of operating a wireless electronic device in a radio communications network having at least first and second geographically separated antenna nodes that are coupled to a base station, the method comprising:

when the electronic device is at a first location within range of the first antenna node, establishing a first uplink communications path with the base station via the first antenna node; and

when the electronic device is at a second location within range of the second antenna node, terminating the first uplink communications path and establishing a second uplink communications path with the base station via the second antenna node.

18. The method defined in claim 17 further comprising:

receiving first reference signals from the first antenna node; and

receiving second reference signals from the second antenna node.

19. The method defined in claim 17 further comprising:

performing radio-frequency measurements on the first and second reference signals; and

sending the radio-frequency measurement results to the base station.

20. The method defined in claim 19 wherein terminating the first uplink communications path comprises terminating the first uplink communications path in response to the radio-frequency measurements associated with the first reference signals falling below a predetermined threshold.