Tamed spread spectrum method based on quasi-regular LDPC code

In order to realize a low complexity tamed spread spectrum system based on long codes, a novel tamed spread spectrum system based on quasi-regular low density parity check (QR-LDPC) code was proposed. This system employs a new LDPC code called quasi-regular LDPC which is constructed using degree distribution optimization method. A synchronization algorithm exploits check constraint was proposed, and then the complexity of synchronization for long code tamed spread spectrum was reduced. Simulations show that the proposed tamed spread spectrum is an effective and feasible scheme adopt long codes, both spreading gain and coding gain could be achieved. The bit error rate performance of proposed system is also better than traditional direct sequence spread spectrum system since the spread factor is equal.