Method and system to provide increased data throughput in a wireless multi-hop network

• US 7,031,293 B1
• Filed: 03/26/2001
• Issued: 04/18/2006
• Est. Priority Date: 03/26/2001
• Status: Expired due to Term

• Current Assignee: Hitachi Energy Switzerland AG (Hitachi, Ltd.)
• Original Assignee: Tropos Networks Incorporated (ABB Limited)
• Inventors: Behroozi, Cyrus, Srikrishna, Devabhaktuni, Chari, Amalavoyal
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Wong, Blanche
• Application Number:
  US09/818,423
• Time in Patent Office: 1,849 Days
• Field of Search: 370/346, 370/348, 370/431, 370/443, 370/449
• US Class Current: 370/348
• CPC Class Codes: H04K 2203/18 for wireless local area networks or WLAN
• CPC Class Codes: H04K 3/226 Selection of non-jammed channel for communication spectrum sharing arrangements H04W16/14; selection of wireless resources by user or terminal H04W72/02
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

It is the object of this invention to provide a method of increasing the data throughput of a multi-hop wireless link. A method is provided which mitigates self-interference, without precluding the use of omni-directional transceivers. Distributed protocols for channel allocations in a multi-hop wireless communication system are described. These protocols result in channel allocations that increase the capacity utilization of the network and render the system robust to localized interferers and jammers.

Claims

1. A channel assignment scheme for a node of a mesh network, comprising:

the node determining a number of hops between the node and a server of the mesh network;

assigning a first channel to an uplink for the node;

assigning a second channel for a downlink for the node;

maintaining the first channel and the second channel distinct from an uplink channel of an upstream node;

wherein the assignment of first channel and the second channel for the node is based on the number of hops between the node and the server.

2. The method of claim 1, wherein there are multiple downlink nodes and the multiple downlink nodes use multiple downlink channels.

3. The method of claim 1, wherein the number of hops is determined from routing information carried in routing packets.

4. The method of claim 3, wherein the routing information is propagated in the network on some or all of the channels available in the system.

5. The method of claim 3, wherein the routing information is propagated in the network on a dedicated channel.

6. The method of claim 1, wherein the uplink channel of the node is assigned by a default gateway.

7. The method of claim 6, wherein assigning the downlink channel for a node comprises:

determining a plurality of potential channels for communication;

sending a reservation packet to trigger testing of each of the plurality of potential channels; and

assigning the downlink channel based on responses to the reservation packet.

8. The method of claim 7, wherein testing comprises:

each downstream node sending a plurality of packets to the node; and

evaluating a channel with a link quality greater than other channels.

9. The method of claim 8 wherein link quality is estimated by the throughput on the link.

10. The method of claim 8 wherein link quality is estimated by measuring the packet error rate on the link.

11. The method of claim 8 wherein link quality is estimated by the signal-to-noise ratio observed on the link.

12. The method of claim 8 wherein link quality is estimated by the latency observed on the link.

13. The method of claim 1, wherein the channels are frequency channels.

14. The method of claim 1, wherein the channels are different spreading codes in a spread-spectrum CDMA system.

15. The method of claim 1, wherein the channels are different polarizations of the transmitted waveform.

16. The method of claim 1, wherein the channels are different spatial signatures as determined by a smart antenna or adaptive antenna array at the receiver.

19. The method of claim 16, wherein assigning the downlink channel for a node comprises:

determining a plurality of available channels for communication;

sending a reservation packet to trigger testing of each of the plurality of available channels; and

determining a channel based on responses to the reservation packet.

20. The method of claim 19, wherein testing comprises:

each downstream node sending a plurality of packets to the node; and

evaluating a channel based on link quality.

17. A channel assignment scheme for a node of a mesh network, comprising:

determining a number of hops between the node and a server of the mesh network;

assigning a first channel to an uplink for the node;

assigning a second channel to a downlink for the node;

maintaining the first channel and the second channel distinct from an uplink channel of an upstream node; and

assigning the first channel and the second channel for the node based on a number of hops from the node to the server and a number of available channels.

18. The method of claim 17, wherein data regarding number of hops to the distinguished node is carried within a routing packet to the node.

21. A node comprising:

a transceiver having two interfaces, wherein each interface has a channel;

and a channel manager, the channel manager to assign a first channel for a first interface to an uplink for a node and a second channel for a second interface to a downlink for the node, wherein the assignment of first channel and the second channel for the node is based on a number of hops from the node to a server.

22. The node of claim 21, wherein each interface is half-duplex.

23. The node of claim 21, wherein the channels are frequency channels.

24. The node of claim 21, wherein the channels are different spreading codes in a spread-spectrum CDMA system.

25. The node of claim 21, wherein the channels are different polarizations of the transmitted waveform.

26. The node of claim 21, wherein the channels are different spatial signatures as determined by a smart antenna or adaptive antenna array at the receiver.