Link acquisition in wireless communication systems

Patent metadata

Field	Value
Publication number	US-10116375-B2
Application number	US-201715604943-A
Country	US
Kind code	B2
Filing date	May 25, 2017
Priority date	Dec 31, 2015
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A procedure to establish a link in a directional wireless system where two nodes cannot listen to each other unless optimized beamforming pair is used and timing and framing synchronization is acquired. The procedure determines a set of beamforming pairs that the nodes can use for communication in addition to acquiring the framing and timing synchronization. Training packets are periodically transmitted by a transmitter while a receiver listens in each of a number of receive directions. Training packets are sent N times in N directions while a receiver listens in each of M receive directions until all N×M possible transmit and receive direction pair possibilities are tried. The receiver informs the transmitter which transmit and receive direction pairs were successful in creating communication links between the nodes.

First claim

We claim:

1. A node for use in a wireless communication network, wherein the node comprises:
a transceiver that transmits and receives packet data on a wireless communication frequency;
a plurality of antennas with which radio frequency signals are transmitted and received at the node;
a beamformer with which a transmit and receive direction can be changed by the node; and
a processor that is configured to execute instructions to identify one or more transmit and receive beamforming direction pairs between the node and a responder node in a point-to-point wireless communication network, wherein each transmit and receive beamforming direction pair includes a transmit beamforming direction of the node and a receive beamforming direction of the responder node, and wherein the receive beamforming direction is set by delaying and summing receive signals to direct a listening direction of the responder node by:
asynchronously transmitting training packets for a number of times in each of a number of transmit beamforming directions;
receiving an indication that the responder node has asynchronously detected a training packet and is synchronized to the node; and
once the node and the responder node are synchronized,
synchronously transmitting training packets from the node for a number of times in each of a number of possible transmit beamforming directions;
listening for feedback from the responder node that indicates that a training packet was received on a particular receive beamforming direction and listening direction of the responder node; and
using a transmit and receive beamforming direction pair with which a training packet was received by the responder node to transmit data packets to the responder node.

2. The node of claim 1 , wherein the node is configured to asynchronously transmit training packets before synchronously transmitting training packets from the node for a number of times in each of a number of possible transmit beamforming directions.

3. The node of claim 1 , wherein the node is configured to asynchronously transmit a training packet twice in a time period that is less than a receive period of the responder node.

4. The node of claim 1 , wherein the training packet includes synchronization information with which the responder node synchronizes to the network.

5. The node of claim 1 , wherein the node has N transmit beamforming directions and the node is configured to transmit N training packets in each of the N transmit beamforming directions.

6. The node of claim 1 , wherein the node is configured to send an indication of a transmit/receive beamforming direction pair to a network controller computer.

7. The node of claim 5 , wherein the node is configured to receive a routing table from a network controller computer indicating a ranking of transmit/receive beamforming pairs to be used in communicating with the responder node.

8. The node of claim 7 , wherein the node is configured to change transmit beamforming directions in accordance with the ranking when attempting to communicate with the responder node.

9. The node of claim 1 , wherein the node is configured to transmit a training packet in one transmit beamforming direction and listen in a different receive beamforming direction for a signal from the responder node indicating that the responder node has detected the training packet.

10. The node of claim 1 , wherein the number of transmit beamforming directions is a prime number.

11. The node of claim 1 , wherein the node is configured to include frame structure information in the asynchronously transmitted training packets.

12. The node of claim 1 , wherein the node is configured to include frame periodicity information in the asynchronously transmitted training packets.

13. A method, comprising:
transmitting and receiving, by a transceiver of a node, packet data on a wireless communication frequency, wherein the packet data is transmitted and received at the node through a plurality of antennas, and wherein a beamformer of the transceiver of the node changes a transmit and receive direction;
identifying one or more transmit and receive beamforming direction pairs between the node and a responder node in a point-to-point wireless communication network, wherein each transmit and receive beamforming direction pair includes a transmit beamforming direction of the node and a receive beamforming direction of the responder node, and wherein the receive beamforming direction is set by delaying and summing receive signals to direct a listening direction of the responder node, comprising;
asynchronously transmitting training packets for a number of times in each of a number of transmit beamforming directions;
receiving an indication that the responder node has asynchronously detected a training packet and is synchronized to the node; and
once the node and the responder node are synchronized,
synchronously transmitting training packets from the node for a number of times in each of a number of possible transmit beamforming directions;
listening for feedback from the responder node that indicates that a training packet was received on a particular receive beamforming direction and listening direction of the responder node; and
using a transmit and receive beamforming direction pair with which a training packet was received by the responder node to transmit data packets to the responder node.

14. The method of claim 13 , further comprising asynchronously transmitting training packets before synchronously transmitting training packets from the node for a number of times in each of a number of possible transmit beamforming directions.

15. The method of claim 13 , further comprising asynchronously transmitting a training packet twice in a time period that is less than a receive period of the responder node.

16. The method of claim 13 , further comprising sending, by the node, an indication of a transmit/receive beamforming direction pair to a network controller computer.

17. The method of claim 16 , further comprising receiving, by the node, a routing table from a network controller computer indicating a ranking of transmit/receive beamforming pairs to be used in communicating with the responder node.

18. The method of claim 17 , further comprising changing transmit beamforming directions, by the receiving node, in accordance with the ranking when attempting to communicate with the responder node.

19. The method of claim 17 , further comprising transmitting, by the node, a training packet in one transmit beamforming direction and listen in a different receive beamforming direction for a signal from the responder node indicating that the responder node has detected the training packet.

20. A wireless network with an initiator node and a responder node, wherein the initiator node comprises:
a transceiver that transmits and receives packet data on a wireless communication frequency;
a plurality of antennas with which radio frequency signals are transmitted and received at the initiator node;
a beamformer with which a transmit direction and a receive direction can be changed by the initiator node; and
a processor that is configured to execute instructions that cause the initiator node to identify one or more transmit and receive beamforming direction pairs between the initiator node and the responder node in the wireless communication network, wherein each transmit and receive beamforming direction pair includes a transmit beamforming direction of the node and a receive beamforming direction of

Assignees

• Facebook Inc

Inventors

• Kohli Sanjai
• Tujkovic Djordje
• Gomadam Krishna

Classifications

• H04B7/088 Primary

  using beam selection · CPC title

• H04B7/063

  Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection · CPC title

• H04B7/0695

  using beam selection · CPC title

• H04B7/0696

  Determining beam pairs · CPC title