정 진폭 부호화된 Multi-code Biorthogonal Code Keying 시스템에서 인터리빙과 $Q^2PSK$를 이용하여 정 진폭 특성을 유지하면서 대역폭 효율을 개선시키는 방안

Multi-code Biorthogonal Code Keying with Constant Amplitude Coding using Interleaving and $Q^2PSK$ for maintaining a Constant Amplitude feature and increasing Bandwidth Efficiency

A multi-code biorthogonal code keying (MBCK) system consists of multiple waveform coding blocks, and the sum of output codewords is transmitted. Drawback of MBCK is that it requires amplifier with high linearity because its output symbol is multi-level. MBCK with constant amplitude precoding block (CA-MBCK) has been proposed, which guarantees sum of orthogonal codes to have constant amplitude. The precoding block in CA-MBCK is a redundant waveform coder whose input bits are generated by processing the information bits. Redundant bits of constant amplitude coded CA-MBCK are not only used to make constant amplitude signal but also used to improve the BER performance at the receiver. In this paper, we proposed a transmission scheme which combines CA-MBCK with $Q^2PSK$ modulation to improve bandwidth efficiency of CA-MBCK and also uses chip interleaving to maintain a constant amplitude feature of CA-MBCK. bandwidth efficiency of a proposed transmission scheme is increased fourfold. And the BER performance of the scheme is same as that of CA-MBCK.