Patent ID: 9204262
Filing Date: 2015-12-01
Classification: H04L,H04W

Abstract:
1. A fountain code-based cooperative multicast method for a cell of origin (COO) comprising a base station (BS) and some users that demand for a same multicast service, wherein said multicast service is used in a same frequency band and said BS encodes data of said multicast service with a fountain code, the method comprising steps of: 1) continuously modulating a carrier with said data that is encoded by a fountain code and transmitting said data outwards by said BS; receiving said data by users with different channel conditions in a same frequency band; after receiving a feedback that all users complete receiving said data, ending the transmitting said data by said BS; accumulating, by a user, a mutual information from a received fountain code symbol, said mutual information represented as I after receiving said fountain code symbol, trying to decode said fountain code symbol by said user at periodic intervals; wherein when said mutual information accumulated is smaller than an entropy of data that is waiting to be transmitted, the decoding by said user fails, continuing receiving said fountain code symbol to accumulate said mutual information and trying to decode again said fountain code symbol by said user; wherein when said mutual information accumulated is larger than said entropy of said data that is waiting to be transmitted, said user is able to decode said fountain code symbol correctly; and completing receiving said data and feeding back an ACK signal by said user for informing said BS that said user has completed receiving correctly said data; 2) after decoding correctly and completing receiving said data by said user, transmitting said feedback by said user to said BS for informing said BS that said user has received said data and then starting to monitor a “help” signal of other users by said user in a dedicated channel; wherein when receiving said “help” signal by said user that has decode correctly, starting to coordinate through decoding forwarding by said user and transmitting outwards by said user a fountain code encoded symbol that is same as said fountain code encoded symbol of said BS; and when receiving a feedback that all coordinated users complete receiving said data by said user that is coordinating, ending a cooperation by said user that is coordinating.