Generalized Orthogonal Complementary Code System Based On Overlap Multiple Coding

The correlation characteristic of CDMA spread-spectrum sequence is the key factor to influence their performance. According to their auto correlation and multi correlation characteristics, spread spectrum system can eliminate multi-path interference and multi-access interference. Due to Welch limit, the spread spectrum sequence with ideal correlation characteristic is not exited. Through the complement operation with each spread spectrum division code, this Orthogonal Complementary Code can archive the ideal correlation characteristic. Based on traditional Complement Code, the paper analyzes the Generalized Orthogonal Complementary Code with more division code. The number of spread spectrum sequence with ideal correlation is also increased.In the next, the paper analyzes the system that uses Overlap Code Division Multiple (OvCDM) as the spread matrix of Generalized Orthogonal Complementary Code. OvCDM is the chip-level shift overlap multiple of spread matrix, and the Generalized Orthogonal Complementary Code used with OvCDM for co-frequency network deployment is called Overlap Code Division Multiple Access (OvCDMA). Through the design of OvCDM matrix, OvCDMA can eliminate the intra-cell interference in a high code rate and archive strong coding gain.According to the complexity issue, to archive more coding gain only through the increment of constraint length is not a good method. Therefore the system that uses concatenate iterative decoding system with OvCDM should be concerned. The paper uses OvCDM coder as the inner coder of serial concatenate, analyzes the factors that influence the performance of this concatenate system, and design a bit-level interleaved serial concatenate iterative decoding OvCDM system with high performance in a low complexity. Further more, according to OvCDM can be used as the spread matrix of Orthogonal Complementary Code, the paper offers the OvCDMA system used with bit-level interleaved iterative decoding.