Wireless communication system employing an intermediate protocol layer

• US 7,457,274 B2
• Filed: 05/30/2007
• Issued: 11/25/2008
• Est. Priority Date: 12/03/2001
• Status: Expired due to Term

• Current Assignee: Psion PLC (Motorola Solutions, Inc.)
• Original Assignee: Psion Teklogix (Motorola Solutions, Inc.)
• Inventors: Fantaske, Steve
• Primary Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US11/755,460
• Publication Number:
  US 20080037488A1
• Time in Patent Office: 545 Days
• Field of Search: 37039552-39553, 370/238, 370/310, 370/310.1, 370/315, 370/338, 370/349, 370355-359, 370/395.31, 370/392, 370/409, 370465-471, 370/908, 370911-913, 370328-329, 370/341, 370/395.5, 370474-475, 370/481, 710105-106, 709202-203, 709/218, 709227-230, 4555541-5542, 455/41.2, 455516-517, 455 632- 634, 455/426.2, 455448-449, 455/466, 455/555, 455/550.1, 455/556.2, 455557-558, 455/562.1, 455/403, 455/524, 455560-561, 713/151, 726 14- 15
• US Class Current: 370/338
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0018 based on latency requirement
• CPC Class Codes: H04L 1/0019 in which mode-switching is based on a statistical approach
• CPC Class Codes: H04L 1/002 Algorithms with memory of the previous states, e.g. Markovian models
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 12/4604 LAN interconnection over a backbone network, e.g. Internet, Frame Relay
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/146 Markers for unambiguous identification of a particular session, e.g. session cookie or URL-encoding
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 80/06 : Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

A network controller for facilitating roaming of a mobile wireless communications device between access points communicates with at least one access point over a wired network which, in turn, communicate with a mobile wireless communications device over a wireless network. The network controller includes a data processing system including a protocol stack that facilitates a communication session between the mobile device and a network device on the wired network, and a session table identifying session information for each said communication session. The session information identifies the current access point with which the mobile device is currently associated. The protocol stack updates the session table from session information received from the current access point, maintains a first virtual circuit with the network device, maintains a second virtual circuit with the current access point, and bridges communication between the virtual circuits in accordance with the session information.

Claims

1. A system for a mobile wireless communication, comprising:

one or more access points, each being accessible from a wireless mobile device, the mobile device being associated with a current access point among the one or more access points; and

a network controller for a communication between a network device and the mobile device via the current access point;

the network controller comprising;

a first protocol layer configured to maintain a first virtual circuit between the network controller and the network device;

a second protocol layer configured to maintain a second virtual circuit between the network controller and the current access point; and

an intermediate protocol layer configured to bridge a communication between the first virtual circuit and the second virtual circuit through mapping,

wherein the second protocol layer is configured to extract a first data segment encapsulated into a second data segment received via the second virtual circuit and pass it to the intermediate protocol layer for transmission to the network device, the first data segment comprising message data from the mobile device and a session number for identifying the network device,

wherein the intermediate protocol layer is configured to extract the message data and map the extracted message data to the first virtual circuit based on the session number,

and wherein the second protocol layer is further configured to receive data from the intermediate protocol layer and process the received data for transmission to the current access point.

2. The system according to claim 1, wherein the network controller comprises a session table for identifying the current access point.

3. The system according to claim 1, wherein the intermediate protocol layer is configured to extract the message data of the mobile device from the first data segment, and map the extracted message data to the first virtual circuit based on the session number that identifies a data format of the message data.

4. The system according to claim 1, wherein the access point comprises a third protocol layer for communication with the network controller and the mobile device, and wherein the third protocol layer is associated with the second protocol layer.

5. The system according to claim 1, wherein the first data segment comprises a header, and wherein the first data segment header has a length less than a TCP/IP header.

6. The system according to claim 1, wherein the session number is used to identify a data format of the message data received from the mobile device.

7. The system according to claim 1, wherein the access point periodically broadcasts a beacon data frame having a unique number associated with the access point to allow the mobile device to identify that it is in range of the access point, and transmits a boot number to the network controller when receiving a response with the boot number from the mobile device.

8. A system for a mobile wireless communication, the system comprising:

a data processing system including a protocol stack for facilitating a communication session between a mobile device and a network device, message data being passed from the mobile device to the data processing system via a current access point, the protocol stack comprising;

a first protocol layer configured to maintain a first virtual circuit between the system and the network device;

a second protocol layer configured to maintain a second virtual circuit between the system and the current access point; and

an intermediate protocol layer configured to bridge communication between the first virtual circuit and the second virtual circuit through mapping,

wherein the second protocol layer is configured to extract a transport layer data segment encapsulated in a base station link layer datagram transmitted from the current access point over the second virtual circuit, the message data being encapsulated in the transport layer data segment,

wherein the second protocol layer is further configured to transmit the extracted transport layer data segment to the intermediate protocol layer for transmission to the network device,

wherein the transport layer data segment comprises a transport layer header having a session number for identifying a data format of the message data and the network device, and

wherein the intermediate protocol layer is further configured to extract the message data from the transport layer data segment and to map the extracted message data to the first virtual circuit based on the session number.

9. The system according to claim 8, wherein the data processing system comprises a session table for identifying session information, the session information identifying the current access point.

10. The system according to claim 8, wherein the transport layer header has a length less than a TCP/IP header.

11. The system according to claim 8, wherein the first virtual circuit is maintained with a TCP protocol layer on the network device, the second virtual circuit being maintained with a TCP protocol layer on the access point.

12. The system according to claim 8, wherein the intermediate protocol layer is configured to bridge the communication by mapping the transport layer data segment between the virtual circuits.

13. A method for a mobile wireless communication, comprising the steps of:

at a current access point, encapsulating a first data segment for transmission to a network controller into a second data segment, the first data segment comprising message data from a mobile device and a session number for identifying a network device;

at the network controller, controlling a communication between the network device and the current access point, the network controller having at a first protocol layer configured for maintaining a first virtual circuit between the network controller and the network device, a second protocol layer configured for maintaining a second virtual circuit between the network controller and the current access point, and an intermediate protocol layer configured for bridging a communication between the first virtual circuit and the second virtual circuit;

the step of controlling including;

at the second protocol layer, extracting the first data segment encapsulated into the second data segment received via the second virtual circuit and passing it to the intermediate protocol layer for transmission to the network device;

at the intermediate protocol layer, extracting the message data from the first data segment and mapping the extracted message data to the first virtual circuit based on the session number; and

at the second protocol layer, receiving data from the intermediate protocol layer and processing the received data for transmission to the current access point.

14. The method according to claim 13, wherein the first data segment comprises a header, and wherein the first data segment header has a length less than a TCP/IP header.

15. The method according to claim 13, wherein the session number is used to identify a data format of the message data received from the mobile device.

16. The method according to claim 13, further comprising:

at the access point,

periodically broadcasting a beacon data frame having a unique number associated with the access point to allow the mobile device to identify that it is in range of the access point, and

transmitting a boot number to the network controller when receiving a response with the boot number from the mobile device.

17. A method for a mobile wireless communication between a mobile device and a network device via a network controller, the network control including a first protocol layer configured for maintaining a first virtual circuit between the network controller and the network device, a second protocol layer configured for maintaining a second virtual circuit between the network controller and a current access point associated with the mobile device, an intermediate protocol layer configured for bridging a communication between the first virtual circuit and the second virtual circuits,

the method comprising the steps of:

at the second protocol layer, extracting a transport layer data segment encapsulated in a base station link layer datagram transmitted from the current access point over the second virtual circuit, the transport layer data segment comprising message data from the mobile device and a session number for identifying the network device;

at the second protocol layer, transmitting the extracted transport layer data segment to the intermediate protocol layer for transmission to the network device;

at the intermediate protocol layer, extracting the message data from the transport layer data segment and mapping the extracted message data to the first virtual circuit based on the session number.

18. The method according to claim 17, wherein the transport layer data segment comprises a header, and wherein the transport data segment header has a length less than a TCP/IP header.

19. The method according to claim 17, wherein the session number is used to identify a data format of the message data received from the mobile device.