Methods and apparatus for uplink macro-diversity in packet-switched cellular networks
View Patent ↗A method and apparatus for providing uplink macro-diversity in packet-switched networks that allows packets and/or portions of packets, e.g., frames, to be selectively sent from an end node, e.g., wireless communication device or mobile terminal, over a set of multiple communication connections, e.g., physical-layer or link-layer connections, to one or more access nodes, e.g., base stations. Uplink macro-diversity is achieved in part through intelligent selective forwarding over multiple communication connections, where the forwarding decision is controlled by the end node based on a variety of factors, e.g., physical-layer channel conditions and/or higher layer policy. The forwarding decision is executed on a rapid timescale, e.g., on a per packet basis, to adapt to the dynamically varying conditions of the set of communication connections.
1. A method of operating a wireless terminal, comprising:
maintaining a plurality of communications connections between the wireless terminal and at least two different receivers;
monitoring channel conditions on the communications connections;
selecting one of the plurality of communications connections based on the monitored channel conditions;
controlling packet size as a function of the monitored channel conditions, wherein controlling comprises signaling a source of the packets to generate packets of a different size;
transmitting at least a portion of a packet using the selected communications connection; and
repeating the monitoring, selecting and transmitting steps, wherein multiple communications connections are selected for uplink transmissions during a period of time in which a single communications connection is used for downlink transmissions to the wireless terminal.
2. The method of claim 1 , wherein each transmitted portion of a packet is directed over a single one of the communications connections to a single one of the receivers.
3. The method of claim 2 , wherein portions of packets transmitted over a first selected communications connection are transmitted using a first communications protocol and wherein portions of packets transmitted over a second selected communications connection are transmitted using a second communications protocol that is different than the first communications protocol.
4. The method of claim 3 , wherein the first communications protocol is compatible with the Institute of Electrical and Electronics Engineers (IEEE) 802.11b protocol and the second communications protocol is an orthogonal frequency-division multiplexing (OFDM) based communications protocol.
5. The method of claim 2 , wherein the selecting comprises selecting a new connection after transmitting an entire packet, wherein a next packet is transmitted on the selected new connection.
6. The method of claim 5 , wherein the receivers are located at different access nodes.
7. The method of claim 5 , wherein the receivers are located at a same access node.
8. The method of claim 2 , wherein a frame corresponds to a portion of a packet, the selecting step being performed to correspond to frame boundaries such that a new connection is selected after transmitting a frame, wherein a next frame is transmitted on the selected new connection.
9. The method of claim 8 , wherein the receivers are located at different access nodes.
10. The method of claim 8 , wherein the receivers are located at a same access node.
11. The method of claim 10 , wherein different portions of a first packet are transmitted over different communications connections.
12. The method of claim 11 , further comprising:
operating the access node to combine the different portions of the first packet transmitted over different communications channels to reassemble the first packet; and
operating the access node to transmit the reassembled first packet to another node.
13. The method of claim 12 , wherein the access node is a base station.
14. The method of claim 1 , wherein the communications connections are physical layer connections.
15. The method of claim 1 , wherein the communications connections are link layer connections.
16. The method of claim 1 , wherein the controlling further comprises controlling a transmission packet length by fragmenting packets to be transmitted into smaller packets.
17. The method of claim 1 , wherein the selecting is performed independent of handoff between access nodes.
18. The method of claim 1 , wherein the selecting is based on physical layer channel conditions.
19. The method of claim 1 , wherein the selecting is based on link layer channel conditions.
20. The method of claim 1 , wherein the selecting is based on layer characteristics other than physical layer characteristics or link layer characteristics.
21. The method of claim 1 , wherein the selecting is based on at least one of packet content, packet size, packet type, higher layer policy and a communications protocol to which the packet corresponds.
22. The method of claim 21 , wherein the selecting comprises:
selecting a same communications connection to transmit portions of packets corresponding to a specific communications protocol during the period of time; and
selecting between different communications connections during portions of the period of time used for transmitting portions of packets which do not correspond to the specific communications protocol.
23. A wireless terminal, comprising:
a processor;
memory in electronic communication with the processor;
instructions stored in the memory, the instructions being executable by the processor to:
maintain a plurality of communications connections between the wireless terminal and at least two different receivers;
monitor channel conditions on the communications connections;
select one of the plurality of communications connections based on the monitored channel conditions;
control packet size as a function of the monitored channel conditions, wherein controlling comprises signaling a source of the packets to generate packets of a different size;
transmit at least a portion of a packet using the selected communications connection; and
repeat the monitoring, selecting and transmitting, wherein multiple communications connections are selected for uplink transmissions during a period of time in which a single communications connection is used for downlink transmissions to the wireless terminal.
24. The wireless terminal of claim 23 , wherein each transmitted portion of a packet is directed over a single one of the communications connections to a single one of the receivers.
25. The wireless terminal of claim 23 , wherein the communications connections are physical layer connections.
26. The wireless terminal of claim 23 , wherein the communications connections are link layer connections.
27. The wireless terminal of claim 24 , wherein the instructions executable to select comprise instructions executable to select a new connection after transmitting an entire packet, wherein a next packet is transmitted on the selected new connection.
28. The wireless terminal of claim 23 , wherein the instructions executable to select comprise instructions executable to select independent of handoff between access nodes.
29. The wireless terminal of claim 23 , wherein the instructions executable to select comprise instructions executable to select based on physical layer channel conditions.
30. The wireless terminal of claim 23 , wherein the instructions executable to select comprise instructions executable to select based on link layer channel conditions.
31. The wireless terminal of claim 23 , wherein the instructions executable to select comprise instructions executable to select based on layer characteristics other than physical layer characteristics or link layer characteristics.
32. A wireless terminal, comprising:
means for maintaining a plurality of communications connections between the wireless terminal and at least two different receivers;
means for monitoring channel conditions on the communications connections;
means for selecting one of the plurality of communications connections based on the monitored channel conditions;
means for controlling packet size as a function of the monitored channel conditions, wherein the means for controlling comprise means for signaling a source of the packets to generate packets of a different size;
means for transmitting at least a portion of a packet using the selected communications connection; and
means for repeating the monitoring, selecting and transmitting steps, wherein multiple communications connections are selected for uplink transmissions during a period of time in which a single communications connection is used for downlink transmissions to the wireless terminal.
33. The wireless terminal of claim 32 , wherein each transmitted portion of a packet is directed over a single one of the communications connections to a single one of the receivers.
34. The wireless terminal of claim 33 , wherein the means for selecting selects a new connection after transmitting an entire packet, wherein a next packet is transmitted on the selected new connection.
35. The wireless terminal of claim 32 , wherein the means for selecting operates independent of handoff between access nodes.
36. A non-transitory computer-readable medium having instructions thereon, the instructions being executable to:
maintain a plurality of communications connections between a wireless terminal and at least two different receivers;
monitor channel conditions on the communications connections;
select one of the plurality of communications connections based on the monitored channel conditions;
control packet size as a function of the monitored channel conditions, wherein controlling comprises signaling a source of the packets to generate packets of a different size;
transmit at least a portion of a packet using the selected communications connection; and
repeat the monitoring, selecting and transmitting, wherein multiple communications connections are selected for uplink transmissions during a period of time in which a single communications connection is used for downlink transmissions to the wireless terminal.
37. The computer-readable medium of claim 36 , wherein each transmitted portion of a packet is directed over a single one of the communications connections to a single one of the receivers.
38. The computer-readable medium of claim 37 , wherein the instructions executable to select comprise instructions executable to select a new connection after transmitting an entire packet, wherein a next packet is transmitted on the selected new connection.
39. The computer-readable medium of claim 36 , wherein the instructions executable to select comprise instructions executable to select independent of handoff between access nodes.