Wireless communication system

• US 6,922,557 B2
• Filed: 12/03/2001
• Issued: 07/26/2005
• Est. Priority Date: 10/18/2000
• Status: Expired due to Term

• Current Assignee: Psion Inc (Zebra Technologies Corporation)
• Original Assignee: Psion Teklogix (Motorola Solutions, Inc.)
• Inventors: Fantaske, Steve
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US09/998,442
• Publication Number:
  US 20020045435A1
• Time in Patent Office: 1,331 Days
• Field of Search: 455423-415, 455/426.2, 455/554.2, 455/555, 455/560, 455/561, 455/95, 455/107, 455/115.1
• US Class Current: 455/403
• 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 wireless network communication system consists of an access server for facilitating communication between a network resource interfacing with the access server over a land-based network and a wireless communications device interfacing with the access server over a wireless network. A message intended for transmission from the wireless communication device to the network resource is transmitted to the access server over a wireless network as a number of message datagrams. Upon receipt of the message datagrams over the wireless network, the access server generates and transmits to the wireless communication device an acknowledgement datagram indicating successful receipt of each message datagram, and transmits the successfully received message datagrams to the network resource over the land-based network. If a message datagram is not acknowledged, the wireless communication device continues to retransmit the unsuccessfully transmitted message datagram at a retransmission rate based on a running average of acknowledgment times for successfully transmitted ones of the message datagrams.

Claims

1. A wireless communication device, comprising:

an antenna configured for communication over a wireless network; and

a data processing system in communication with the antenna, the data processing system including a protocol stack for facilitating communication over the wireless network, the protocol stack comprising an intermediate protocol layer configured to;

(i) transmit electronic message datagrams from the antenna over the network, and maintain a running average of acknowledgment times of successfully transmitted ones of the datagrams; and

(ii) initiate retransmission of unsuccessfully transmitted ones of the datagrams after a retransmission interval of magnitude which is initially the running average of the acknowledgment times, and which increases from that magnitude after a predetermined number of unsuccessful retransmission attempts of the unsuccessfully transmitted one datagram.

2. The communication device according to claim 1, wherein the intermediate protocol layer comprises a message monitor implemented at a data link layer and which is configured to increase the retransmission interval until a maximum upper limit is reached, and to maintain the retransmission interval at that maximum upper limit until the unsuccessfully transmitted one datagram is successfully transmitted.

3. The communication device according to claim 2, wherein the message monitor is configured to wait for an acknowledgement signal received at the data link layer in response to a successful transmission of one of the datagrams from the data link layer, and to update the running average in accordance with a duration of each wait.

4. The communication device according to claim 3, wherein each said electronic passage comprises message data, the intermediate protocol layer further comprises a message processor implemented at a transport layer, the message processor is configured to format the message data into at least one transport layer data segment, and the message monitor is configured to format the at least one transport layer data segments into at least one link layer datagram, each transport layer data segment and link layer datagram having a respective header, the transport layer header and the link layer header having a combined length less than a TCP/IP header.

5. The communication device according to claim 4, wherein the transport layer header includes a session number transport layer parameter identifying a data format of the message data, and a radio address transport layer parameter uniquely associated with a mobile wireless communication device, and the data processing system is configured to relay the electronic data between the mobile wireless communication device and a process on a wired network in accordance with the session number and the radio address.

6. The communication device according to claim 5, wherein the the communications device comprises the mobile wireless communications device.

7. A method of wireless data communication over a wireless network, the method comprising the steps of:

at a wireless communication device initiating transmission of electronic message datagrams over the wireless network, and maintaining a running average of acknowledgment times of successfully transmitted ones of the datagrams; and

initiating retransmission of unsuccessfully transmitted ones of the message datagrams after a retransmission interval of magnitude which is initially the running average of the acknowledgment times, and which increases from that magnitude after a predetermined number of unsuccessful retransmission attempts of the unsuccessfully one datagram.

8. The method according to claim 7, wherein the retransmission interval increasing step comprises the steps of increasing the retransmission interval until a maximum upper limit is reached, and maintaining the retransmission interval at that maximum upper limit until the unsuccessfully transmitted one datagram is successfully transmitted.

9. The method according to claim 8, wherein the wireless communication device has a protocol stack facilitating the wireless data communication, the protocol stack including a data link layer for transmitting the datagrams from the link layer, and the retransmission step comprises the steps of for each said transmitted message datagram waiting an acknowledgement time period for receipt of an acknowledge signal at the data link layer in response to a successful transmission of one of the datagrams, and updating the running average in accordance with a duration of each wait.

10. The method according to claim 9, wherein each said electronic message comprises message data, and the message transmission step comprises the steps of formatting the message data into at least one transport layer data segment, and formatting the at least one transport layer data segments into at least one link layer datagram, each transport layer data segment and link layer datagram having a respective header, the transport layer header and the link layer header having a combined length less than a TCP/IP header.

11. The method according to claim 10, wherein the transport layer header includes a session number transport layer parameter identifying a data format of the message data, and a radio address transport layer parameter uniquely associated with a mobile wireless communication device, and the method further comprises relaying the electronic data between the mobile wireless communication device and a process on a wired network in accordance with the session number and the radio address.

12. An access server for facilitating communication of electronic data between a network resource interfacing with the access server over a wired network and a mobile wireless communications device interfacing with the access server over a wireless network, the access server comprising:

a network interface for communicating with the network resource over the wired network;

an antenna for communicating with the wireless communications device over the wireless network; and

a data processing system in communication with the network interface and the antenna, the data processing system including a protocol stack comprising;

(i) an intermediate protocol layer comprising a message processor layer implemented at a transport layer for formatting the electronic data into at least one transport layer data segment, and a message monitor layer implemented at a data link layer for formatting the at least one transport layer data segment into at least one link layer datagram, each transport layer data segment and link layer datagram having a respective header, the transport layer header and the link layer header having a combined length less than a TCP/IP header, the transport layer header including a session number transport layer parameter identifying a data format of the electronic data;

(ii) a first physical protocol layer in communication with the intermediate protocol layer for facilitating communication of the datagrams over the wireless network,

(iii) a second physical protocol layer for facilitating communication of the datagrams over the wired network, and

(iv) an application protocol layer in communication with the intermediate protocol layer and the second physical protocol layer for mapping the electronic data between the wireless communications device and the network resource in accordance with the session number.

13. The access server according to claim 12, wherein the transport layer header includes a radio address transport layer parameter uniquely associated with the mobile wireless communications device, and the data processing system is configured to map the electronic data between the mobile wireless communications device and the process in accordance with the radio address.

14. The access server according to claim 13, wherein the message monitor layer is configured to initiate transmission of the datagrams over the wireless network;

and to maintain a running average of acknowledgment times of successfully transmitted ones of the datagrams.

15. The access server according to claim 14, wherein the message monitor layer is configured to initiate retransmission of unsuccessfully transmitted ones of the datagrams after a retransmission interval of magnitude which is initially the running average of the acknowledgment times, and which increases from that magnitude after a predetermined number of unsuccessful retransmission attempts of the unsuccessfully transmitted one datagram.

16. The access server according to claim 15, wherein the message monitor layer is configured to increase the retransmission interval until a maximum upper limit is reached, and to maintain the retransmission interval at that maximum upper limit until the unsuccessfully transmitted on datagram is successfully transmitted.

17. A method of electronic data communication between a network resource associated with a wired network and a mobile wireless network communications device associated with a wireless network via an access server associated with the wired network, the access server having a communications protocol stack comprising an application protocol layer, a message processor layer implemented at a transport layer, and a message monitor layer implemented at a data link layer, the method comprising the steps of:

receiving the electronic data from the wireless network, the electronic data comprising message data encapsulated into at least one transport layer data segment, the at least one transport layer data segment being encapsulated into at least one link layer datagram, each transport layer data segment and link layer datagram having a respective header, the transport layer header and the link layer header having a combined length less than a TCP/IP header, the transport layer header including a session number transport layer parameter identifying a data format of the electronic data;

at the message monitor layer extracting the at least one transport layer data segment from the received at least one link layer datagram;

at the message processor layer extracting the message data from the received at least one transport layer data segment; and

at the application protocol layer mapping the extracted message data between the mobile wireless communications device and the network resource in accordance with the session number.

18. The method according to claim 17, wherein the transport layer header includes a radio address transport layer parameter uniquely associated with the mobile wireless communications device, and the mapping step comprises mapping the message data between the mobile wireless communications device and the network resource in accordance with the radio address.

19. The method according to claim 18, further comprising the steps of:

at the message monitor layer initiating transmission of the datagrams over the wireless network;

at the message monitor layer initiating transmission of the datagrams over the wireless network, and

initiating retransmission of unsuccessfully transmitted ones of the datagrams after a retransmission interval of magnitude which is initially the running average of the acknowledgment times, and which increases from that magnitude after a predetermined number of unsuccessful retransmission attempts of the unsuccessfully transmitted one datagram.

20. The method according to claim 19, wherein the step of increasing the retransmission interval comprises increasing the retransmission interval until a maximum upper limit is reached, and maintaining the retransmission interval at that maximum upper limit until the unsuccessfully transmitted on datagram is successfully transmitted.

21. An electronic signal for facilitating communication with a mobile wireless communications device over a wireless network, comprising:

a message;

at least one transport layer data segment encapsulating the message, each transport layer data segment having a transport layer header; and

at least one link layer datagram encapsulating the transport layer data segment, each link layer datagram having a link layer header, the transport layer header and the link layer header having a combined length less than a TCP/IP header, the transport layer header including a session number parameter identifying a data format of the message.

22. The electronic signal according to claim 21, wherein the transport layer header includes a radio address parameter uniquely associated with the mobile wireless communications device.