Methods and apparatus for downlink macro-diversity in cellular networks

• US 7,623,477 B2
• Filed: 11/05/2003
• Issued: 11/24/2009
• Est. Priority Date: 05/06/2002
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Park, Vincent, Corson, M. Scott, Laroia, Rajiv, Kapoor, Samir
• Primary Examiner(s): Pezzlo; John
• Application Number:
  US10/702,000
• Publication Number:
  US 20040141502A1
• Time in Patent Office: 2,211 Days
• Field of Search: 370/430, 370/328, 370/329, 370/349, 370/278, 370/466, 370/467, 370331-334, 370/400, 370/401, 370/389, 370/252, 370/237, 713/153
• US Class Current: 370/278
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/185 using make before break
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The invention described herein enables a form of downlink macro-diversity in packet-switched cellular networks. It allows packets to be selectively delivered from a network/internetwork to an end node, e.g., a wireless communication device or terminal, over a set of available link-layer connections to/from the end node, through one or more access nodes, e.g., base stations. Downlink macro-diversity is particularly important when the link-layer connections between the end node and the corresponding access node, e.g., the access links, are subject to independent or partially correlated time variations in signal strength and interference. In accordance with the invention, the end node dynamically selects the downlink to be used out of a set of available access links on a per packet basis subject to prevailing channel conditions, availability of air-link resources and other constraints. The invention improves the robustness and efficiency of communication, overall utilization of air-link resources, and quality of service experienced by the end node.

Claims

1. A communications method by an end node, comprising:

maintaining a plurality of communications links, a first communications link being between said end node and a first access node, and a second communications link being between said end node and a second access node;

initiating selective packet replication from a mobility agent node to the second access node;

monitoring which one of said plurality of communications links is preferred for transmitting packets to said end node at any given time;

requesting transmission of packets from said first access node by sending a first signal to said first access node when the first communications link is preferred, the first signal indicating that a flow of packets should be forwarded to the end node by the first access node; and

requesting termination of transmission of packets from said first access node by sending a second signal to said first access node when the second communications link is preferred, the second signal indicating that the flow of packets should be discarded by the first access node for at least a portion of time during which time packets are being received by said end node from said second access node.

2. The communications method as in claim 1 wherein during a first period of time packets from said first access node are transmitted to said end node, and wherein during a second period of time packets from said second access node are transmitted to said end node, said first and second periods of time being consecutive periods of time with at least some of the packets transmitted to said end node during said first and second period or time being non-duplicative.

3. The communications method as in claim 1 further comprising reconstructing packets received from said first and second access nodes as a single series of nackets.

4. The communications method as in claim 1 further comprising controlling which one of said plurality of communications links for transmission of packets based on said monitoring.

5. The communication method as in claim 1 further comprising requesting transmission of packets from one of said first and second access nodes by sending yet another signal to another of said first and said access nodes.

6. An end node in a communications system, comprising:

means for maintaining a plurality of communications links, a first communications link being between said end node and a first access node, and a second communications link being between said end node and a second access node;

means for initiating selective packet replication from a mobility agent node to the second access node;

means for monitoring which one of said plurality of communications links is preferred for transmitting packets to said end node at any given time;

means for requesting transmission of packets from said first access node by sending a first signal to said first access node when the first communications link is preferred, the first signal indicating that a flow of packets should be forwarded to the end node by the first access node; and

means for requesting termination of transmission of packets from said first access node by sending a second signal to said first access node when the second communications link is preferred, the second signal indicating that the flow of packets should be discarded by the first access node for at least a portion of time during which time packets are being received by said end node from said second access node.

7. The end node as in claim 6 wherein during a first period of time packets from said first access node are transmitted to said end node, and wherein during a second period of time packets from said second access node are transmitted to said end node, said first and second periods of time being consecutive periods of time with at least some of the packets transmitted us said end node during said first and second period or time being non-duplicative.

8. The end node as in claim 6 further comprising means for reconstructing packets received front said first and second access nodes as a single series of packets.

9. The end node as in claim 6 further comprising means for controlling which one of said plurality of communications links for transmission of packets based on said monitoring.

10. The end node as in claim 6 further comprising means for requesting transmission of packets from one of said first and second access nodes by sending yet another signal to another of said first and said access nodes.

11. The end node as in claim 6 wherein said packets are IP (Internet Protocol) packet portions.

12. A communications apparatus, comprising:

processor; and

circuitry coupled to said processor configured to maintain a plurality of communications links, a first communications link being between said end node and a first access node, and a second communications link being between said end node and a second access node, the circuitry also being configured to initiate selective packet replication from a mobility agent node to the second access node, monitor which one of said plurality of communications links is preferred for transmitting packets to said end node at any given time, request transmission of packets from said first access node by sending a first signal to said first access node when the first communications link is preferred, the first signal indicating that a flow of packets should be forwarded to the end node by the first access node, and the circuitry also being configured to request termination of transmission of packets from said first access node by sending a second signal to said first access node when the second communications link is preferred, the second signal indicating that the flow of packets should be discarded by the first access node for at least a portion of time during which time packets are being received by said end node from said second access node.

13. The communications apparatus as in claim 12 wherein during a first period of time packets from said first access node are transmitted to said end node, and wherein during a second period of time packets from said second access node are transmitted to said end node, said first and second periods of time being consecutive periods of time with at least some of the packets transmitted to said end node during said first and second period or time being non-duplicative.

14. The communications apparatus as in claim 12 wherein said circuitry counted to said processor being further configured to reconstruct packets received from said first and second access nodes as a single series of packets.

15. The communications apparatus as in claim 12 wherein said circuitry coupled to said processor being further configured to control which one of said plurality of communications links for transmission of packets based on said monitoring.

16. The communications apparatus as in claim 12 wherein said circuitry coupled to said processor being further configured to request transmission of packets from one of said first and second access nodes by sending yet another signal to another of said first and said access nodes.

17. The end node as in claim 12 wherein said packets are IP (Internet Protocol) packet portions.

18. A computer-program product for an end node in a communications system, the computer-program product comprising a computer-readable medium having instructions thereon capable of being executed by a computer, the instructions comprising:

code for maintaining a plurality of communications links, a first communications link being between said end node and a first access node, and a second communications link being between said end node and a second access node;

code for initiating selective packet replication from a mobility agent node to the second access node;

code for monitoring which one of said plurality of communications links is preferred for transmitting packets to said end node at any given time;

code for requesting transmission of packets from said first access node by sending a first signal to said first access node when the first communications link is preferred, the first signal indicating that a flow of packets should be forwarded to the end node by the first access node; and

code for requesting termination of transmission of packets from said first access node by sending a second signal to said first access node when the second communications link is preferred, the second signal indicating that the flow of packets should be discarded by the first access node for at least a potion of tune during which time packets are being received by said end node from said second access node.