Data transfer method for wire real-time communications

• US 6,496,481 B1
• Filed: 07/16/1998
• Issued: 12/17/2002
• Est. Priority Date: 07/16/1998
• Status: Expired due to Term

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Wu, Chiung-Shien, Ma, Gin-Kou
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US09/116,681
• Time in Patent Office: 1,615 Days
• Field of Search: 370/242, 370/310, 370/473, 714/748, 714/738, 714/749
• US Class Current: 370/242
• CPC Class Codes: H04L 1/1628 List acknowledgements, i.e. the acknowledgement message consisting of a list of identifiers, e.g. of sequence numbers H04L1/1614 takes precedence
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/1832 Details of sliding window management
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 28/0273 adapting protocols for flow control or congestion control to wireless environment, e.g. adapting transmission control protocol [TCP] wireless network protocols or protocol adaptations to wireless operation, e.g. wireless application protocol H04W80/00
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

A transport protocol that meets the requirements and performance for multimedia data transfer in a wireless link includes a transmitting/sending station and a receiving station. The inventive protocol is referred to as the Burst-oriented Transport with Time-bounded Retransmission (BTTR). This scheme uses a large transmission window for sending/receiving a burst of time-sensitive data and, within this window, several smaller observation windows are used for dynamic error retransmission. There is a time limitation on each retransmission such that the burst of data can be received in a timely manner, and thus trading some packet losses (still in an acceptable range) for delay and throughput performance. Specifically, the wireless network includes a wireless station for transmitting data over a wireless link. The sending station transmits a plurality of sequential data packets to the receiving station, wherein each plurality of sequential data packets form a respective Group-of-Packet (GOP). The receiving station detects whether any of the received data packets in each current GOP are corrupted before receipt of all data packets in the current GOP. The receiving station then transmits a negative acknowledgement (ACK) packet to the sending station before the receipt of all data packets in the current GOP, if at least one data packet in the current GOP is corrupted. Note that the ACK packet indicates which data packets are corrupted. In addition, the sending station selectively retransmits the data packets based on the indication of the received ACK packet before transmitting the next GOP to the receiving station.

Claims

1. A transport protocol process for transmitting data from a sending station to a receiving station over a wireless link, wherein said protocol prohibits using positive acknowledgement (ACK) packets, said process comprising the steps of:

transmitting, by said sending station, a plurality of sequential data packets to said receiving station, wherein each said plurality of sequential data packets form a respective Group-of-Packet (GOP);

detecting whether any of said received data packets in each current GOP are corrupted before receipt of all data packets in said current GOP;

transmitting, by said receiving station, a negative acknowledgement (NAK) packet to said sending station, before the receipt of all data packets in said current GOP, only if at least one of said data packets in said current GOP is corrupted, wherein said NAK packet indicates corrupted data packets; and

selectively transmitting, by said sending station, said data packets indicated by the received NAK packet before transmitting the next GOP to said receiving station if a predetermined time is unexpired,

wherein the prohibition of said ACK packets reduces data propagation delays.

2. The process of claim 1, wherein said step of detecting detects corrupted data packets the step of analyzing all data packets in a buffer of said receiving station once every predetermined time period.

3. The process of claim 2, wherein said predetermined time period equals time required to transmit a complete GOP.

4. The process of claim 1, wherein said NAK packet comprises a GOP identifier and a packet sequence number to indicate which data packets in which GOPs contain corrupted data.

5. The process of claim 2, wherein said sending station includes a buffer having a storage capacity of n+(2×

tp) packets, where n equals the number of packets in a GOP, and tp equals the propagation delay.

6. The process of claim 2, wherein the receiving station buffer having a storage capacity of 2×

(n−

u) packets, where n equals the number of packets in a GOP, and u equals the time to transmit said NAK packet.

7. The process of claim 1, wherein the predetermined time is once.

8. The process of claim 1, wherein n equals the number of packets in a GOP and the U^th packet represents a predetermined packet in the sequence of packets in said GOP, and further comprising the steps of:

setting a counter equal u;

receiving, at said receiving station, a current packet in said GOP;

recovering from a corrupted packet if the received packet was retransmitted;

decreasing said counter by 1 if said received packet is new;

transmitting an NAK packet and setting said counter equal to n if said received packet is said u^th packet; and

receiving, at said receiving station, a next packet.

9. A network including a wireless station for transmitting data over a wireless link, wherein said network prohibits using positive acknowledgement (ACK) packets, comprising:

a receiving station; and

a sending station for transmitting a plurality of sequential data packets to said receiving station,

wherein each said plurality of sequential data packets form a respective Group-of-Packet (GOP),

wherein said receiving station detects whether any of said received data packets in each current GOP are corrupted before receipt of all data packets in said current GOP,

wherein said receiving station transmits a negative acknowledgement (NAK) packet to said sending station, before the receipt of all data packets in said current GOP, only if at least one of said data packets in said current GOP is corrupted, where said NAK packet indicates corrupted data packets,

wherein said sending station selectively retransmits said data packets based on the indication of the received NAK packet before transmitting the next GOP to said receiving station if a predetermined time is unexpired, and

wherein the prohibition of said ACK packets reduces data propagation delays.

10. The network of claim 9, further comprising a wired station coupled to said wireless station, for receiving said data packets therefrom.

11. The network of claim 9, wherein said sending and receiving station each include a buffer, respectively.

12. The network of claim 9, wherein and receiving station analyzes all data packets in the receiving buffer, to determine said corrupted data packets, once every predetermined time period.

13. The network of claim 12, wherein said predetermined time period equals time required to transmit a complete GOP.

14. The network of claim 9, wherein said NAK packet comprises a GOP identifier and a packet sequence number to indicate which data packets in which GOPs contain corrupted data.

15. The network of claim 11, wherein the sending station buffer having a storage capacity of n+(2×

tp) packets, where n equals the number of packets in a GOP, and tp equals the propagation delay.

16. The network of claim 11, wherein the receiving station buffer being of a size capable of storing 2×

(n−

u) packets, where n equals the number of packets in a GOP, and u equals the time to transmit said ACK packet.