COGNITIVE WIFI RADIO NETWORK

• US 20120257585A1
• Filed: 04/05/2012
• Published: 10/11/2012
• Est. Priority Date: 04/05/2011
• Status: Active Grant

• Current Assignee: Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Industry, Through The Communications Research Centre Canada
• Original Assignee: Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Industry, Through The Communications Research Centre Canada
• Inventors: Sydor, John, Roberts, David, Doray, Bernard, Palaninathan, Siva, Brett, Wayne, Bennai, Mustapha
• Granted Patent: US 8,923,225 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The invention relates to a cognitive radio (CR) WiFi network which includes a plurality of radio environment aware WiFi terminals, which collect local WiFi interference information and send this information to a CR network management system (NMS). The CR NMS includes a database for storing historical records of the interference information obtained from the terminals, and cognitive engines for analyzing the stored historical interference records and determining terminal-specific transmission and reception parameters. In one embodiment the network implements a deterministic NMS-directed networks-wide TDD/TDM scheduling of WiFi communications for optimal channel re-use and interference avoidance, and a novel terminal synchronization mechanism.

Claims

1. A method for avoiding interference in a WiFi network comprising a plurality of WiFi terminals, the method comprising:

a) using one or more of the WiFi terminals to collect radio interference information, wherein the radio interference information comprises packet header information for WiFi packets received over a plurality of WiFi channels;

b) communicating the radio interference information from the one or more of the WiFi terminals to a network management system (NMS) for storing in a network radio environment database (NRED); and

,

c) receiving transmission and reception parameters sent by the NMS to the one or more of the WiFi terminals for use thereof in WiFi data communications by said one or more of the WiFi terminals so as to avoid or lessen radio interference in the WiFi network.

2. A method of claim 1, wherein the transmission and reception parameters comprise at least one of:

WiFi channel identifier for data communication, time slot assignments, transmission power assignments, and transmission data rate.

3. A method of claim 1, wherein the packet header information comprises one or more parameters selected from the list of:

base station identifier (BSID), service set identifier (SSID), source MAC address, destination MAC address, payload size, modulation rate, packet type, and channel of WiFi transmission.

4. A method of claim 3, wherein the radio interference information further comprises at least one of:

received signal strength indicator (RSSI), WiFi channel identifier of the WiFi packet reception, occupancy time for the WiFi channel of the WiFi packet reception.

5. A method of claim 1, wherein the NMS transmits to the WiFi terminals a list of WiFi signal parameters to be collected in step (a).

6. A method of claim 2, wherein the NMS analyzes the radio interference information received from the WiFi terminals and creates historical interference records for each of the WiFi terminals, the historical interference records comprising information related to one or more of the following:

WiFi terminal location, direction of the antenna used by the WiFi terminal to collect interference information, WiFi terminal transmission and reception data throughput rates, time of the collection of the radio interference information by the WiFi terminal, an identifier of the WiFi channel wherein WiFi interference was detected, and an average received signal strength of the WiFi packets received from all WiFi interference sources.

7. A method of claim 6, wherein the historical interference record for at least one of the WiFi terminals comprises time stamped information related to WiFi packets received over one or more of WiFi channels, including a source address of the WiFi packets, channel occupancy from the source address, an average RSSI related to the source address, and a number of WiFi packets received from the source address.

8. A method of claim 2, wherein the NMS transmits to each of the WiFi terminals a terminal-specific time slot assignment message specifying transmission and reception time slots for the respective WiFi terminal.

9. A method of claim 8, wherein the terminal-specific time slot assignment message is transmitted using the TCP/IP protocol in the form of a scheduling code word (SCW), and wherein the terminal-specific time slot assignment message further specifies:

transmission and reception antenna directions by time slot or by WiFi packet destination address, and transmission power levels by time slot or by WiFi packet destination address for the respective WiFi terminal.

10. A method of claim 9, wherein each of the WiFi terminals executes the time slot assignments in accordance with the received SCW upon a reset of an internal terminal time (TT) counter, the method further comprising synchronising resets of the TT counters of different WiFi terminals to periodic synchronization events.

11. A method of claim 10, wherein the periodic synchronization events comprise one of:

a GPS time reference signal, and a detection of a WiFi beacon frame.

12. A method of claim 10, wherein the plurality of WiFi terminals comprises an access point (AP) terminal and a client terminal in communication with the AP terminal, wherein the AP terminal periodically transmits the WiFi beacon frame at a prescribed time interval, the method comprising:

re-setting the TT counter of the client terminal upon receiving the beacon frame from the AP terminal to a new TT value, wherein the new TT value is one of;

a zero, or a non-zero TT value obtained based on a value of the TT counter of the AP terminal at beacon transmission contained in a broadcast packet received from the AP terminal.

13. A method of claim 2, wherein the WiFi terminals comprise directional antennas for selectively transmitting and receiving WiFi signals in a plurality of spatial directions, and wherein:

the radio interference information collected by each of the WiFi terminals and communicated to the NMS specifies antenna directions used by the WiFi terminal to receive the WiFi packets while collecting the radio interference information; and

,

the transmission and reception parameters that the NMS communicates to the WiFi terminals specify transmission or reception direction for the directional antenna in dependence upon at least one of;

a time slot or a WiFi packet destination.

14. A WiFi terminal comprising:

one or more WiFi radios configured for;

supporting WiFi data communications over one or more WiFi channels in accordance with channel and transmission time slot assignments received from the NMS, and,

sensing radio signals in other WiFi channels that are not assigned to the respective WiFi terminal for data communications, and detecting WiFi packets therein; and

one or more processor for collecting interference information related to the WiFi packets detected in the other WiFi channels, wherein the interference information comprises packet header information, for transmitting to a network management system (NMS) using a wired or wireless connection.

15. A WiFi terminal of claim 14, wherein the one or more radios of the WiFi terminal comprise:

a first WiFi radio comprising a WiFi transmitter and a WiFi receiver for providing WiFi data communications for the WiFi terminal, and

a second WiFi radio comprising at least a WiFi receiver for sensing radio signals in the other WiFi channels that are not assigned to the WiFi terminal for data communications, and for detecting WiFi packets therein.

16. A WiFi terminal of claim 15, including:

a data port for receiving data packets to be transmitted using the first WiFi radio;

a packet transmission control circuit (PTCC) comprising a terminal time (TT) counter and disposed in a data path between the data port and the first WiFi radio for temporary storing the received data packets, and for releasing the received data packets to the first WiFi radio for WiFi transmission in time slots synchronized to the TT counter and in accordance with the time slot assignments or an antenna direction assignment received from the NMS.

17. A WiFi terminal of claim 16, including a GPS receiver coupled to the processor for providing location information thereto for transmitting to the NMS, and coupled to the PTCC for providing timing synchronization pulses thereto for resetting an internal timing counter thereof.

18. A WiFi terminal of claim 16 comprising a TT control logic for providing a beacon frame announcement signal to the PTCC for resetting the TT counter thereof.

19. A WiFi terminal of claim 16, further comprising a directional antenna having an antenna direction control module, and a communication path between the PTCC and the antenna direction control module for controlling the transmission direction of the antenna in accordance with the antenna direction assignment received from the NMS.

20. A WiFi terminal of claim 16, wherein the PTCC comprises a plurality of FIFO buffer memory modules for temporary storing data packets for transmitting to a plurality of different destinations in the WiFi network in accordance with the time slot assignment received from the NMS.

21. A WiFi network system, comprising:

a plurality of the WiFi terminals as defined in claim 14, and

the network management system (NMS);

wherein the NMS further comprises;

a collector module for collecting the interference information from the WiFi terminals, and for communicating the transmission and reception parameters comprising the channel and transmission time slot assignments to the WiFi terminals;

a network radio environment database (NRED) for storing time-stamped records of the interference information collected from the WiFi terminals; and

,

an analysis module for analyzing historical records of the interference information stored in the NRED and for generating the transmission and reception parameters for the WiFi terminals.