Efficient and reliable transmission via a hybrid broadcast-point-to-point system

• US 7,386,621 B1
• Filed: 08/31/2000
• Issued: 06/10/2008
• Est. Priority Date: 08/31/2000
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hlasny, Daryl
• Primary Examiner(s): PATEL, ASHOKKUMAR B
• Application Number:
  US09/653,073
• Time in Patent Office: 2,840 Days
• Field of Search: 709/240, 709/241, 709/242, 709/244, 709/245, 709/249, 709/239, 709/232, 398/66, 714/818, 714/819, 714/820, 714/821, 714/822, 714/823, 714/825, 725/87, 725/101
• US Class Current: 709/230
• CPC Class Codes: H04L 12/1868 Measures taken after transmission, e.g. acknowledgments
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04N 21/41407 embedded in a portable device, e.g. video client on a mobile phone, PDA, laptop constructional details of equipment or arrangements specially adapted for portable computer application G06F1/1626; arrangements specially adapted for mobile receivers in broadcast systems H04H20/57
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6408 Unicasting

Abstract

In wireless networks, data objects are typically transferred from a data distributor to a data recipient by reliable point-to-point communication between the distributor and the recipient. However, the time to transfer data by point-to-point communication can become excessive if the number of recipients is large. Efficient and reliable data transfer is provided by a system incorporating broadcast and point-to-point communication topologies. The data is initially broadcast to all recipients. Data broadcasting is followed by polling the recipients. If the data missing after a broadcast can be transferred in less time by point-to-point communication then that topology is chosen to complete the transfer. If not, the missing data is broadcast again to all recipients. The efficiency of the broadcast phase can be improved by designating a representative to acknowledge successful data transfer on behalf of all recipients. A most suitable representative of all recipients can be selected by comparing missing data for each recipient to the missing data of all other recipients.

Claims

1. A method of transferring data from a distributor to a plurality of recipients comprising the steps of:

(a) broadcasting a sequential one of a plurality of packets together comprising data to be transferred to said plurality of recipients at a time when each said plurality of recipients is capable of receiving said data by point-to-point communication;

(b) repeating step (a) until a time for the completion of transferring said sequential one of a plurality of packets by point-to-point communication with said recipients obtains a predetermined relationship to a time for the completion of said broadcasting, wherein each successive iteration of repeating step (a) is preceded by the steps of;

(i) receiving a value from at least one designated representative recipient, each representing at least one other non-representative recipient, said value indicating whether said sequential one of said plurality of packets has been received;

(ii) assigning said received value to all recipients respectively represented by said at least one of said designated recipients; and

(iii) evaluating whether said predetermined relationship has been attained based on said respective received values and said assigned values;

(c) thereafter completing said transferring of said sequential one of a plurality of packets by point-to-point communication with at least one of said plurality of recipients; and

(d) repeating steps (a) through (c) for the next sequential one of said plurality of packets until said data has been received by all recipients.

2. The method of claim 1 wherein the step of repeating said broadcasting until a time for transferring said sequential one of a plurality of packets by point-to-point communication with said recipients obtains a predetermined relationship to a time for said broadcasting comprises the steps of:

(a) estimating a time to transfer said sequential one of a plurality of packets by point-to-point communication with said recipients, and

(b) repeating said broadcasting of said sequential one of a plurality of packets if said time to transfer said sequential one of a plurality of packets by point-to-point communication is greater than said time to broadcast said data.

3. The method of claim 2 wherein the step of estimating a time to transfer said sequential one of a plurality of packets by point-to-point communication with said recipients comprises the steps of:

(a) polling at least one recipient to identify non-receipt of said sequential one of a plurality of packets by said at least one recipient;

(b) estimating a time to successfully transfer said sequential one of a plurality of packets to said recipient by point to point communication; and

(c) summing said estimated times to successfully transfer said sequential one of a plurality of packets to recipients not reporting receipt of said sequential one of a plurality of packets.

4. The data transfer method of claim 1 wherein the step of repeating said broadcasting of said sequential one of a plurality of packets until a time for transferring said sequential one of a plurality of packets by point-to-point communication with said recipients obtains a predetermined relationship to a time for said broadcasting comprises the steps of:

(a) estimating a time to transfer unreceived instances of said sequential one of a plurality of packets by point-to-point communication with said recipients,

(b) estimating a count of unreceived instances of said sequential one of a plurality of packets following an additional broadcast; and

(c) rebroadcasting said sequential one of a plurality of packets if said time to transfer said unreceived instances of said sequential one of a plurality of packets by point-to-point communication with said recipients is greater than a sum of said time to broadcast said sequential one of a plurality of packets and a time to transfer said estimated count of said sequential one of a plurality of packets by point-to-point communication.

5. The method of claim 4 wherein the step of estimating a time to transfer said sequential one of a plurality of packets by point-to-point communication with said recipients comprises the steps of:

(a) polling at least one recipient to identify unreceived data for said recipient;

(b) estimating a time to successfully transfer said unreceived data to said recipient by point to point communication; and

(c) summing said estimated times to successfully transfer said unreceived data to recipients reporting unreceived data.