Retransmission protocol and coding scheme for multicast broadcast service

1. A method for retransmitting L original data packets in a multicast broadcast service comprising the steps of:

transmitting M coded packets selected from the L original data packets by grouping the L packets into a number of sets according to a predetermined grouping rule;

generating a retransmission packet R i through the effect of a binary summation (XOR) of packets selected from the number of sets;

transmitting packet R i ; and

transmitting any additional coded packets as needed wherein said predetermined grouping rule is a fixed one selected from predetermined grouping rules for a given L such that a decoding packet error rate is minimized and no feedback is provided.

2. The method of claim 1 wherein said grouping step groups the L original packets into 2 M sets exemplarily denoted as Ω 0 , . . . , Ω 2 M −1 , where M represents a number of retransmission packets.

3. The method of claim 1 wherein said predetermined grouping rule is chosen from predetermined sets of grouping rules for a given L that minimize a decoding packet error rate.

4. The method of claim 2 wherein said generating step comprises the steps of:

generating the retransmission packet R i by binary XORing packets from the selected sets from the 2 M sets according to the following relationship:

R m =Σ⊕ P i εV m P i , with V m ={Ω j , j bin (m)=1},

where Σ⊕ denotes binary summation and j bin (m) denotes the m th bit of the binary representation of j.

5. The method of claim 1 further comprising the steps of:

Encoding P 1 ,. . .,P L based on another code graph thereby generating additional packets for retransmissions.

6. A method for retransmitting L original data packets in a multicast broadcast service comprising the steps of:

transmitting M coded packets selected from the L original data packets by grouping the L packets into a number of sets according to a predetermined grouping rule;

generating a retransmission packet R i through the effect of a binary summation (XOR) of packets selected from the number of sets;

transmitting packet R i ;

transmitting any additional coded packets as needed,

fixing the L packets into a packet sequence P 1 ,. . ., P L ; and

encoding P 1 ,. . . , P L based on a code graph {Ω}thereby generating M packets for M retransmissions.

7. A method for retransmitting L original data packets in a multicast broadcast service comprising the steps of:

transmitting M coded packets selected from the L original data packets by grouping the L packets into a number of sets according to a predetermined grouping rule;

generating a retransmission packet R i through the effect of a binary summation (XOR) of packets selected from the number of sets;

transmitting packet R i ;

transmitting any additional coded packets as needed; and

encoding P 1 ,. . . , P L based on another code graph thereby generating additional packets for retransmissions.