Tham khảo tài liệu 'satellite communications part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Power and Spectral Efficient Multiuser Broadband Wireless Communication System 411 Arbitrary Diff. Two Ort. j n M code PSK cod. n M Shift. -n . pairs Sys. j k codes codes 1st pair BPSK QPSK 8- PSK 16- PSK 2nd pair BPSK QPSK 8- PSK 16- PSK 3rd pair BPSK QPSK 8- PSK 16- PSK 4rth pair BPSK QPSK 8- PSK 16- PSK Table 1. Cross correlation values for arbitrary code pair Sl. no N K SNR PAPR BER ADR 1 22 64 10 2 24 70 10 3 21 60 14 4 23 68 14 5 18 52 11 6 21 65 12 7 23 67 12 8 19 57 14 Table 2. GA based optimization for the proposed method Natarajan et al 2001 through interference cancelation IC . Fig. 17 shows that BER performance of the proposed subcarrier PIC scheme is significantly better compared to that of block PIC scheme and needless to mention its superior BER performance compared to MMSE scheme of Natarajan et al 2001 . The performance improvement for the proposed subcarrier PIC is due to the twofold advantages in interference cancelation. Since the high data rate transmission uses all sub-carriers the data can be decoded with greater reliability and interference due to these users can be estimated with greater accuracy. This interference when subtracted from the resultant received signal improves detection performance of the low data rate users. On the other hand low data rate transmission uses alternate sub-carriers so subcarriers of high data rate users experience less interference that leads to an improvement in BER performance of the latter.
