Wireless LAN with dynamic channel access management

• US 20030188006A1
• Filed: 03/28/2002
• Published: 10/02/2003
• Est. Priority Date: 03/28/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Bard, Steven R.
• Granted Patent: US 7,028,097 B2
• Time in Patent Office: Days
• US Class Current: 709/232
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A system and method for implementing a peer-to-peer wireless local area network (WLAN) that does not require a conventional wireless access point, yet facilitates many of the features provided by an access point, such as channel access management and Quality of Service functions. A method for dynamically selecting a Channel Access Manager (CAM) that (preferably) has the ability to communicate with the greatest number of wireless stations in a given WLAN is provided. The CAM is then used to manage channel access for the WLAN. A method for selecting one or more proxy CAMs that establish communication paths between the CAM and wireless stations with which the CAM traditionally would not be able to communicate is also provided. The invention also provides a method for resolving the issues that occur when a new station is added to the WLAN, and provides optimize routing of messages to maximize transmission bandwidths.

Claims

1. A method comprising:

assigning one of a plurality of stations in a wireless network that does not include a wireless access point to manage transmission traffic across the wireless network, said one station corresponding to a channel access manager (CAM); and

managing data transmissions between said plurality of stations that are sent over a wireless communication channel provided by the wireless network with the CAM.

2. The method of claim 1, wherein the CAM is assigned by performing the operations of:

determining a count of stations that are within a communication range of each of said plurality of stations; and

assigning a station with the highest count of stations to be the CAM.

3. The method of claim 1, wherein the CAM manages the transmission traffic by performing the operations of:

monitoring the wireless communication channel for a request to send data that is sent to the CAM from another station in the wireless network;

determining when the wireless communications channel is clear; and

sending a message to the station that requested to send data authorizing that station to send its data over the wireless communications channel.

4. The method of claim 1, wherein the CAM manages the transmission traffic by controlling when transmissions over the wireless communications channel may be performed to ensure that none of said plurality of stations is in communication range of more than one transmitting station at a time.

5. The method of claim 4, wherein the transmission traffic may include two or more concurrent transmissions between respective sets of stations, each set of stations including a respective transmitting station and at least one respective target station, and wherein each target station is in communication range of only one transmitting station during the concurrent transmissions.

6. The method of claim 1, further comprising providing a quality of service operation that enables time-critical delivery of data between a transmitting station and a receiving station over the wireless communication channel by preventing other stations from accessing the wireless communication channel until all of the data has been received by the receiving station.

7. The method of claim 1, further comprising assigning at least one of said plurality of stations to perform proxy operations for the CAM to enable the CAM to control channel access for stations in the wireless network that are outside of a communication range of the CAM.

8. The method of claim 7, wherein said at least one station assigned to perform proxy operations for the CAM is determined by

determining an identity of any stations from among said plurality of stations that is within a communication range of another station that is not in the communication range of the CAM;

and

assigning any station meeting the foregoing condition to perform proxy operations for the CAM.

9. The method of claim 8, wherein determining the identity of stations that are assigned to perform proxy operations for the CAM comprises:

sending out a station identification request message from each station requesting any station that receives the message to respond with a message identifying that station;

sending station identification response messages back to the sending stations;

creating a respective list for each station identifying all of the stations that responded to that station;

comparing each respective list with a list identifying the stations that responded to the CAM station to determine if any of said respective lists contains a station that is not listed in a list of stations that responded to the CAM; and

determining the station(s) corresponding to any list that contains a station that is not listed in the list of stations that responded to the CAM.

10. The method of claim 1, further comprising:

determining an optimal routing path from among a plurality of optional routing paths that would enable a given transmission to be sent from a first station to be received by a second station in the shortest amount of time; and

routing the message along the routing path by providing routing information to the first station and any station along the optimal routing path that may be employed to relay the transmission to the receiving station.

11. The method of claim 10, wherein determining the optimal routing path comprises:

monitoring direct transmission bandwidths between each unique pair of stations in the wireless network;

estimating an overall transmission path bandwidth for at least two different routing paths that would enable the given message to be sent from the first station to the second station; and

selecting the routing path having the highest estimated overall transmission path bandwidth.

12. The method of claim 1, wherein the transmission traffic for the wireless network is being managed by an existing CAM, further comprising:

enabling a new station to join the wireless network;

determining if the new station would be a better station to perform the transmission traffic management operations provided by the existing CAM than the existing CAM; and

assigning the new station to be the CAM if it is determined that the new station would be better than the existing CAM for performing the transmission traffic management operations.

13. An article of manufacture comprising:

a machine-readable media on which a plurality of instructions comprising a wireless network driver are stored that when executed by each of a plurality of stations in a wireless network enables management of network transmission traffic across the wireless network by performing the operations of,

selecting a station from among said plurality of stations to perform network communication traffic management operations, said station comprising a channel access manager (CAM);

notifying each of said plurality of stations which station is the CAM; and

obtaining channel access authorization from the CAM prior to transmitting data between stations.

14. The article of manufacture of claim 13, wherein the CAM is selected by performing the operations of:

broadcasting a station identification request message from each station requesting any station within a communication range of the station broadcasting the message to respond with a message identifying that station;

for each station within the communication range of the station that broadcast a station identification request message, sending a station identification response message back to the station that broadcast the station identification request message;

for each of said plurality of stations, determining a count of stations that responded to that station'"'"'s station identification request message;

broadcasting a first message station count message from one of said plurality of stations identifying the count of stations for that station; and

broadcasting subsequent station count messages from zero or more stations identifying the count of stations for each of said zero or more stations, wherein each subsequent message is sent from a station having a count of stations greater than a station that sent a preceding station count message,

wherein a last station to broadcast a station count message becomes the CAM.

15. The article of manufacture of claim 13, wherein the station selected for the CAM manages the network transmission traffic by performing the operations of:

monitoring a wireless network channel for requests to send data that are sent to the CAM from other stations in the wireless network;

determining when the wireless network channel is clear; and

sending messages to the stations that requested to send data authorizing each of those stations to send its data over the wireless network channel.

16. The article of manufacture of claim 13, wherein the CAM manages the network transmission traffic by controlling when transmission between stations may be performed to ensure that no station ever receives concurrent transmissions.

17. The article of manufacture of claim 13, wherein the CAM enables a sending station to deliver data to a receiving station in a time-critical manner by preventing other stations from accessing a wireless channel over which the data is transmitted until all of the data has been received by the receiving station.

18. The article of manufacture of claim 13, wherein execution of the wireless network driver by selected stations enable those stations to perform proxy operations for the CAM to enable the CAM to control network transmission traffic involving one or more stations that are not within a communication range of the CAM.

19. The article of manufacture of claim 18, wherein execution of the wireless network driver by said plurality of stations enables the stations that perform proxy operations to be selected by performing the operations of:

sending out a station identification request message from each station requesting any station that receives the message to respond with a message identifying that station;

in response to receiving a station identification request message, sending a station identification response messages back to the station that sent the station identification request message;

for each station, logging an identity of any station that responded to that station'"'"'s station identification request message into a station identification list;

sending the station identification lists to the CAM;

comparing each respective station identification list sent to the CAM with a station identification list for the CAM to determine if any station identification list sent to the CAM contains a station that is not contained in the station identification list for the CAM; and

identifying any station(s) that sent a station identification list to the CAM that contains a station that is not contained in the station identification list of the CAM,

wherein any station that is identified is selected to perform proxy operations for the CAM.

20. The article of manufacture of claim 13, wherein execution of the wireless network driver by said plurality of stations further performs the operations of:

determining an optimal routing path from among a plurality of optional routing paths that would enable a given transmission to be sent from a first station to be received by a second station in the shortest amount of time; and

routing the message along the routing path by providing routing information to the first station and any station along the optimal routing path that may be employed to relay the transmission to the receiving station.

21. The article of manufacture of claim 13, wherein the machine-readable media comprises a non-volatile storage device that is accessible to a wireless network adapter and said plurality of machine instructions comprise firmware code that is stored in the non-volatile storage device.

22. A wireless local area network (WLAN) comprising:

a first station comprising a channel access manager (CAM) station; and

a plurality of client stations, each client station linked in wireless communication with at least one other client station and/or the CAM station,

wherein the CAM station performs network transmission traffic management operations for the WLAN by controlling when transmission between client stations may occur.

23. The WLAN of claim 22, wherein each of the CAM station and client stations comprise:

a memory, in which a plurality of executable software modules are stored, including an operating system network service and a wireless network driver;

a processor, coupled to the memory; and

a wireless network adapter, coupled to the processor, via which wireless radio signals corresponding to a WLAN communication channel may be transmitted and received,

wherein respective execution of the operating system network service and the wireless network driver by the processors of the CAM station and the client stations enables the CAM station to control access to the WLAN communication channel through a predefined communication protocol comprising a set of channel access control messages that are transmitted between the CAM station and the client stations.

24. The WLAN of claim 23, wherein upon initialization, all of the stations in the WLAN, including the CAM station, comprise client stations, and wherein respective execution of the operating system network service and the wireless network driver by the processors of the CAM station and the client stations selects one of the client stations to become the CAM station by performing the operations of:

determining a count of client stations that are within a communication range of each of said plurality of client stations; and

assigning a station with the highest count of stations to be the CAM station.

25. The WLAN of claim 22, wherein the CAM station manages the network transmission traffic by performing the operations of:

monitoring a wireless communication channel corresponding to the WLAN for a request to send data that is sent to the CAM station from a client station;

determining when the wireless communication channel is clear; and

sending a message to the client station that requested to send data authorizing that client station to send its data over the wireless communications channel.

26. The WLAN of claim 22, further comprising a proxy channel access management (PCAM) station linked in wireless communication with the CAM station and at least one client station that is not linked in wireless communication with the CAM station, said PCAM station serving as a proxy for the CAM station to enable the CAM station to control network transmissions involving said at least one client station that is not linked in wireless communication with the CAM station.

27. The WLAN of claim 26, wherein upon initialization, each PCAM station comprises a client station that is selected to be a PCAM station by performing the operations of:

identifying any client stations in the WLAN that are not within communication range of the CAM,

identifying any client station that is enabled to communicate with a client station that was identified as not being within communication range of the CAM; and

assigning those client stations that are enabled to communicate with a client station that was identified as not being within communication range of the CAM to become a PCAM.

28. The WLAN of claim 22, wherein the CAM station manages the network transmission traffic by controlling when transmissions over a wireless communications channel corresponding to the WLAN may be sent from a transmitting station to one or more receiving stations to ensure that none of said plurality of client stations is in communication range of more than one transmitting station at a time.

29. The WLAN of claim 28, wherein the CAM stations enables a sending client station to deliver data to a receiving client station in a time-critical manner by preventing other client stations from accessing a wireless channel over which the data is transmitted until all of the data has been received by the receiving client station.

30. The WLAN of claim 22, wherein management of the network transmission traffic by the CAM further includes to operations of:

determining an optimal routing path from among a plurality of optional routing paths that would enable a given transmission to be sent from a first client station to be received by a second client station in the shortest amount of time; and

routing the message along the routing path by providing routing information to the first client station and any client station along the optimal routing path that may be employed to relay the transmission to the receiving client station.