Apparatus, and associated method, for communicating packet data in a network including a radio-link

• US 6,757,245 B1
• Filed: 06/01/2000
• Issued: 06/29/2004
• Est. Priority Date: 06/01/2000
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Kuusinen, Jarmo, Turunen, Matti
• Primary Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US09/585,203
• Time in Patent Office: 1,489 Days
• Field of Search: 370/231, 370/230, 370/349, 370/235, 714/748, 714/749
• US Class Current: 370/230
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters

Abstract

Apparatus, and associated method, for improving packet data communications upon a communication path including a radio-link. Determination is made of the conditions on the radio-link when selecting the optimal size of a transmission window within which to transmit packets of data. And, retransmission time-out values are also selected responsive to the indications of the radio-link conditions.

Claims

1. In a communication system in which a packet data is communicated between a network host and a mobile host upon a communication path, the communication path including a radio-link, an improvement of apparatus for the mobile host for selecting a window size within which to transmit a data packet, said apparatus comprising:

a flow monitor for monitoring data throughput flows on the radio-link forming a portion of the communication path between the network host and the mobile host, said flow monitor for generating an indication of the data throughput flows on the radio link; and

a window size selector coupled to receive the indication of the data throughput flows generated by said flow monitor, said window size selector for selecting a window size within which to transmit the data packet.

2. In a communication system in which packet data is communicated between a first host and a second host upon a communication path, the communication path including a radio-link having a forward link and a reverse link, an improvement of apparatus for selecting a window size within which to transmit a data packet, said apparatus comprising:

a radio-link status determiner coupled to receive an indication of a packet data throughput rate upon at least a selected one of the forward link and the reverse link of the radio-link forming a portion of the communication path between the first host and the second host, said radio-link status determiner for determining an indication of a characteristic of the radio-link and for generating a radio-link status indication indicative of the indication of the characteristic determined thereat; and

a window size selector coupled to receive the radio-link status indication generated by said radio-link status determiner, said window size selector for selecting a window size within which to transmit the data packet.

3. The apparatus of claim 2 wherein the indications of the radio-link to which said radio-link status determiner is coupled to receive comprises indications of a RTT (round-trip-time) representative of a time period within which two-way transmission with the first host are determined to be effectuated.

4. The apparatus of claim 3 wherein the time period of which the RTT is representative corresponds to a round-trip time of communication of a data packet and an acknowledgement thereto less time taken in retransmission over the radio link.

5. The apparatus of claim 3 wherein the communication system is defined by logical layers, the logical layers including a layer responsible for control of retransmissions over the radio-link and wherein the time period of which the RTT is representative corresponds to a round-trip time of communication of a data packet and a response thereto less time taken in retransmission at the layer responsible for control of the radio-link.

6. The apparatus of claim 5 wherein the layer responsible for control of retransmissions over the radio-link comprises an RLC (radio-link control) layer.

7. The apparatus of claim 5 wherein the layer responsible for control of retransmissions over the radio-link comprises an RLC (radio-link control) layer.

8. The apparatus of claim 3 wherein the optimal window size selected by said optimal window size selector is proportional to the indication of the data throughput rate and to the RTT.

9. The apparatus of claim 2 wherein the first host comprises a mobile host and the second host comprises a network host and wherein the mobile host is further operable to send a message to the network host, wherein the message includes an offered window field, and wherein a value representative of the optimal window size selected by said optimal window size selector is inserted into the offered window field.

10. The apparatus of claim 9 wherein the network host is operable to receive the message, including the value representative of optimal window size, sent by the mobile host, and to transmit the data packet, the data packet transmitted by the network host within a transmission window of a maximum size corresponding to the optimal window size.

11. The apparatus of claim 9 wherein the mobile host is operable to transmit a data packet, the data packet transmitted by the mobile host within a transmission window of a maximum size corresponding to the optimal window size.

12. The apparatus of claim 2 wherein the first host further comprises a retransmission timer at least for selecting when to retransmit a data packet and wherein said radio-link status determiner is further for determining an indication of a characteristic of the radio-link forming a portion of the communication path and for generating a radio-link quality status indication indicative of the indication of the characteristic determined thereat, a value representative of which is applied to the retransmission timer and responsive to which a time-out value of the retransmission timer is selected.

13. The apparatus of claim 12 wherein the radio-link status indication generated by said radio-link status determiner is representative of changes in the radio-link status between a first selected time and at least a second selected time.

14. The apparatus of claim 13 wherein, if the radio-link status indication is beyond a threshold value, time-out responsive to operation of the retransmission timer is caused to be altered.

15. The apparatus of claim 14 wherein the radio-link status indication comprises a measure of a change in an RTT (round-trip time) representative of a time period within which a data packet is transmitted over the radio-link and an acknowledgment thereto is received.

16. The apparatus of claim 15 wherein the first host and the second host are operable to communicate data packets pursuant to a TCP (transmission control protocol) protocol and the retransmission timer is a TCP retransmission timer for selecting when to retransmit a TCP formatted data packet and wherein a measure is provided of a round trip time representative of a time period within which a TCP formatted packet is transmitted and an acknowledgment thereto is received.

17. The apparatus of claim 15 wherein the time-out value of the retransmission timer is caused to be increased if more than a selected number of data packets are communicated upon the communication path without acknowledgment thereto.

18. The apparatus of claim 15 wherein the time-out value of the retransmission timer is caused to be increased and used in transmission of a selected number of data packets subsequently to be transmitted.

19. The apparatus of claim 15 wherein the time-out value of the retransmission timer is caused to be increased if a data packet is communicated upon the communication path without detection of an acknowledgment thereto.

20. The apparatus of claim 2 wherein the first host comprises a mobile host, the second host comprises a network host, wherein the first and second hosts, respectively, are operable to communicate data packets pursuant to a TCP (transmission control protocol) protocol, and wherein said radio-link status determiner determines the indication of the throughput quality of TCP-formatted data packets.

21. In a communication system in which packet data is communicated between a first host and a second host upon a communication path, the communication path including a radio-link, and the first host having a retransmission timer at least for selecting when to retransmit a data packet, an improvement of apparatus for the first host for selecting a window size within which to transmit the data packet, said apparatus comprising:

a radio-link status determiner coupled to receive indications of the radio-link forming a portion of the communication path between the first host and the second host, said radio-link status determiner for determining an indication of a characteristic of the radio-link and for generating a radio-link quality indication indicative of the characteristic determined thereat; and

a retransmission timer time-out value selector coupled to receive a value representative of the radio-link status indication generated by said radio-link status determiner, said retransmission timer time-out value selector for selecting a time-out value of the retransmission timer responsive to the value representative of the radio-link status indicators.

22. In a method for communicating packet data between a first host and a second host, the first host and the second host connected together by way of a communication path which includes a radio-link, and the first host having a retransmission timer at least for selecting when to retransmit a data packet, an improvement of a method for the first host for selecting a window size within which to transmit a data packet, said method comprising:

determining an indication of throughput on the radio-link;

generating a radio-link status indication indicative of the throughput determined during said operation of determining;

selecting a window size within which to transmit the data packet responsive to a value of the radio-link status indication;

determining an indication of radio-link status of the radio-link forming a portion of the communication path;

generating a radio-link status indication indicative of the indication of the radio-link status determined during said operation of determining; and

adjusting a time-out value of the retransmission timer if the radio-link status indication is beyond a selected threshold.

23. The method of claim 22 wherein the radio-link status indication determined during said operation of determining the indication of radio-link status is representative of changes in the radio-link status.

24. The method of claim 22 wherein the indication of the radio-link status determined during said operations of determining the indication of the radio-link status comprise and indication of a packet data throughput rate.

25. The method of claim 24 wherein the indication of the data throughput rate comprises a RTT (round-trip-time) representative of a time period within which two-way transmissions are effectuated.