Asymmetric protocol for wireless communications

• US 5,570,367 A
• Filed: 07/29/1994
• Issued: 10/29/1996
• Est. Priority Date: 07/29/1994
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Paul, Sanjoy, Ayanoglu, Ender, Sabnani, Krishan K., Gitlin, Richard D., La Porta, Thomas F.
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): NGO, RICKY QUOC
• Application Number:
  US08/282,254
• Time in Patent Office: 823 Days
• Field of Search: 370/13, 370/17, 370/29, 370/32, 370/60, 370/85.7, 370/85.8, 370/91, 370/94.1, 370/95.1, 370/95.2, 370/110.1, 371/32, 371/33, 371/67.1, 371/68.2, 371/69.1, 379/56, 379/58, 379/59, 455/53.1, 455/54.1, 455/54.2, 455/56.1, 455/67.1, 455/68, 455/70
• US Class Current: 370/346
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface
• CPC Class Codes: H04W 92/20 between access points

Abstract

A wireless communications system is arranged to provide data communications services, including error recovery, between at least one wireless end-user device and at least one one base station. The wireless end user device(s) receives(s) from the base station(s) unsolicited messages indicative of the status of data packets received by the base station(s). The wireless end-user device(s) transmit acknowledgement and request for retransmission messages only upon request, or when all the packets within a block of such packets have been received.

Claims

1. A wireless communications system comprising:

at least one base station which

a) transmits data packets to, and receives data packets from at least one wireless end-user device over a wireless link,

b) sends to the at least one wireless end-user device at predetermined periodic intervals i) unsolicited status messages of data packets received from the at least one wireless end-user device, and ii) polling messages to inquire about the status of data packets transmitted to, but unacknowledged by the at least one wireless end-user device after a predetermined time period, and

c) stores channel information for the wireless link, and status information of received and transmitted data packets; and

within the at least one wireless end-user device processing means for

i) determining whether data packets received from the at least one base station are received in sequence, and

ii) requesting retransmission of missing data packets, the processing means having means for time-stamping each data packet prior to the transmission of each data packet by the wireless end-user device, and

in response to a request for retransmission of one or more data packets by the at least one base station, means for computing the difference between the present time and the stamped time of each data packet for which retransmission is being requested, and

the processing means initiating retransmission of the one or more data packets if propagation delay between the at least one wireless end-user device and the at least one base station is less than the computed time difference.

2. The system of claim 1 further comprising

means for the at least one base station for copying from each of N data packets, m bits that are combined in M data packets to form N+M data packets transmitted to the wireless end-user device such that if at least one of the N+M data packets is lost during transmission, N data packets can be reconstructed by the wireless end-user device as long as N data packets out of the N+M data packets are received by the wireless end-user device.

3. The system of claim 1 further comprising:

means for the wireless end-user device for copying from each of N data packets m bits that are combined in M data packets to form N+M data packets transmitted to the at least one base station such that if at least one of the N+M data packets is lost during transmission, N data packets can be reconstructed by the at least one base station as long as N data packets out of the N+M data packets are received by the wireless end-user device.

4. A method of providing data communications services between at least one wireless end-user device and at least one base station over a wireless communications link of a data connection, the method comprising the steps of:

communicating data packets between the at least one wireless end-user device and the at least one base station;

transmitting at predetermined periodic intervals from the at least one base station to the at least one wireless end-user device i) unsolicited status messages of data packets transmitted to the at least one base station by the at least one wireless end-user device, and ii) polling messages to inquire about the status of data packets transmitted by the at least one base station to the at least one wireless end-user device, but unacknowledged by the at least one wireless end-user device after a predetermined time period;

storing in the at least one base station channel information for the wireless link, and status information of data packets received therein and of data packets transmitted to the wireless end-user device;

determining in the at least one wireless end-user device whether data packets transmitted thereto by the at least one base station are received in sequence;

requesting retransmission of missing data packets;

time-stamping each data packet prior to the transmission of each data packet by the wireless end-user device;

in response to a request for retransmission of one or more data packets by the at least one base station, computing the difference between the present time and the stamped time of each data packet for which retransmission is being requested; and

retransmitting the one or more data packets if propagation delay between the at least one wireless end-user device and the the at least one base station is less than the computed time difference.

5. The method of claim 4 further comprising the step of:

copying m bits from each of N data packets, the m bits being combined in M data packets to form N+M data packets transmitted by the at least one base station to the wireless end-user device such that if at least one of the N+M data packets is lost during transmission, N data packets can be reconstructed by the wireless end-user device as long as N data packets out of the N+M data packets are received by the wireless end-user device.

6. The method of claims 4 further comprising the step of:

copying m bits from each of N data packets, the m bits being combined in M data packets to form N+M data packets transmitted by the at least one wireless end-user device to the at least one base station such that if at least one of the N+M data packets is lost during transmission, N data packets can be reconstructed by the at least one base station as long as N data packets out of the N+M data packets are received by the at least one base station.

7. An end-user wireless device for communicating data packets over a cellular network, said device comprising:

a transmitter for sending signaling information to a base station of a wireless network to establish a connection thereto, and thereafter for continuously transmitting sequentially numbered user-data packets to a base station of the cellular network until a buffer in which, each data packet is copied and time-stamped prior to transmission, is full;

a receiver for receiving from the base station a) user-data packets b) messages acknowledging reception of previously transmitted data packets, and c) messages requesting retransmission of unreceived data packets;

in response to receiving a request for retransmission of one or more particular data packets, means for computing the difference between the current time and the stamped time of each particular data packet for which retransmission is requested;

retransmitting each particular data packet for which the computed difference between current time and the stamped time is greater than propagation delay over the cellular network between the wireless end-user device and the base station; and

in response to receiving a request acknowledging reception of specific previously transmitted data packets, means for deleting copies of the specific data packets in the buffer.

8. A base station of a cellular network for communicating data packets, comprising:

a transmitter which exchanges signaling information to a wireless computing device to establish a connection thereto, and thereafter continuously transmits sequentially numbered user-data packets to the wireless computing device until a buffer in which, each data packet is copied prior to transmission, is full;

a receiver which receives from the cellular computing device a) user-data packets, b) messages that acknowledge reception of specific, previously transmitted, data packets, and that request retransmission of unreceived data packets, and signals from a clock that starts and stops a poll timer and a status timer;

in response to receiving a signal indicating that the status timer has expired, means for a) determining whether all packets transmitted thereto by the cellular computing device have been received in sequence and b) requesting from the cellular computing device retransmission of unreceived packets; and

in response to receiving a signal indicating that the poll timer has expired, means for requesting status information of user data packets transmitted to the cellular computing device.