Quadrature amplitude modulation Golay complementary sequences for orthogonal frequency division multiplexing.

摘要

Multicarrier communications including orthogonal frequency-division multiplexing (OFDM) has been adopted for many applications such as wireless local-area networks and digital video broadcasting. Since OFDM can mitigate severe multipath fading unlike other present wireless communication schemes, OFDM is suggested in various wireless applications. Especially, IEEE 802.11 and 802.16 are employing OFDM for wireless local-area network (LAN) applications.; However, a major drawback to OFDM applications is the large peak-to-mean envelope power ratio (PMEPR) of the uncoded OFDM signals because an OFDM signal consists of a number of independently modulated subcarriers, which can give a large peak-to-mean power ratio (PMEPR) when added up coherently. The Golay complementary sequences were proposed to solve the one of main impedient to deploy orthogonal frequency division multiplexing (OFDM), that is, large peak-to-mean envelope power ratio (PMEPR) of the uncoded OFDM signals. The construction of Golay sequences have been successful to the 2h-ary phase shift keying(PSK) modulation, 8 Quadrature amplitude modulation (QAM) and 16-QAM.; In this paper, we try to answer important two problems. First, we constructed new 16-QAM Golay sequences. Since QAM Golay sequence construction consists of linear offsets, the number of Golay sequences depend on the number of linear offsets. Thus, to increase the number of Golay sequences for given modulation, for the purpose of achieving high code rate, the large number of set of linear offset for Golay sequence is desired. We extend the notion of Davis and Jedwab construction of Golay sequences and made a new offsets for Golay sequences. Our modifications of Davis and Jedwab construction of Golay sequences contained all the linear offsets discovered by Chong et al. In addition, we also showed newly discovered linear offsets can be used to construct higher QAM Golay sequences. We explicitly constructed 16 and 64 QAM Golay sequences and derived their PEP bound.