HARQ system in which the output of a turbo coder is applied to a selected one of a plurality of puncturing patterns

摘要

Data of length L symbols is turbo coded to produce a 5L symbol output which is then punctured using one of a plurality of patterns (CO, C1, C2, C3). The applicant refers to the turbo coder output as a 'quasi-complementary turbo code' (QCTC). Each of the patterns select successive symbols from the turbo coder output. The punctured output is transmitted in a sub-packet. As shown in figure 12, the number of symbols in a sub-packet (i.e. the sub-packet length) depends on the pattern selected and on the data rate 1/L at the input to the turbo coder. The patterns are identified using 2 bit sub-packet identifiers (SPIDs). The punctured output may be passed through an interleaver or may be passed through a symbol repeater. The pattern CO is used for initial transmission. If a negative acknowledgment is received data must be re-transmitted. Pattern CO may be used for a first retransmission (chase combining technique) or alternatively patterns C1 or C2 may be used for a first retransmission (incremental redundancy technique). Table 5 shows inter alia SPID, data rate, and the sub-packet length L SC .