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    • 13. 发明授权
    • Multi-layer differential phase shift keying with bit-interleaved coded modulation and OFDM
    • 具有位交织编码调制和OFDM的多层差分相移键控
    • US07324613B2
    • 2008-01-29
    • US10721533
    • 2003-11-25
    • Yuguang FangByung-Seo Kim
    • Yuguang FangByung-Seo Kim
    • H03D3/22H04K1/10
    • H04L27/205H04L27/2071H04L27/2075
    • An efficient system and method for modulation and demodulation to achieve a high data rate using Bit-Interleaved Coded Modulation and OFDM uses either a coherent or a non-coherent transmission scheme using differential modulation. In order to maintain a high data rate impervious to sudden phase changes, a communication system uses an efficient constellation having multiple rings with different sizes and modulation/demodulation schemes utilizing this constellation. In power line communications, the channel gain information is obtained easily at a receiver (100) while the phase information is not. Thus, the communication system uses an absolute magnitude and differential phase coding for modulation and demodulation of the signals.
    • 用于使用比特交错编码调制实现高数据速率的调制和解调的有效系统和方法使用差分调制使用相干或非相干传输方案。 为了保持突发相位变化的高数据速率,通信系统使用具有不同大小的多个环的有效星座和利用该星座的调制/解调方案。 在电力线通信中,在相位信息不是在接收器(100)处容易地获得信道增益信息。 因此,通信系统使用绝对幅度和差分相位编码来进行信号的调制和解调。
    • 18. 发明申请
    • Channel estimation and synchronization with preamble using polyphase code
    • 使用多相码的信道估计和前同步码同步
    • US20050128938A1
    • 2005-06-16
    • US10737339
    • 2003-12-16
    • Yuguang FangByung-Seo Kim
    • Yuguang FangByung-Seo Kim
    • H04J11/00H04L25/02H04L27/26
    • H04L27/2656H04L5/0007H04L5/0048H04L25/0204H04L25/0226H04L27/2605H04L27/2613H04L27/2662
    • A preamble for an OFDM signal synchronizes (104) and estimates (106) the sub-channels with only one code. One polyphase code sequence is used repeatedly for the preamble. The preamble is spread out over the bandwidth, which is the same as an OFDM symbol in the frequency domain and has good autocorrelation characteristics in the time domain. All OFDM signals are added with this preamble at the beginning of the OFDM signal and transmitted on the channel at a transmitter (50). At the receiving end, the receiver (100) first does the autocorrelation process to find out a peak value for synchronization in the time domain. Then, since the polyphase code is known at the receiver, the signal to noise ratio for each sub-carrier is calculated in the frequency domain and smoothed using the normal (Gaussian) distribution to provide the channel estimation. Since the synchronization and channel estimation are processed with a single preamble, the overhead for these two functions is significantly reduced.
    • OFDM信号的前导码同步(104)并仅使用一个码估计(106)子信道。 对于前同步码重复使用一个多相码序列。 前导码在带宽上扩展,与频域中的OFDM符号相同,并且在时域中具有良好的自相关特性。 所有OFDM信号在OFDM信号的开始处与该前同步码相加,并在发射机(50)的信道上发送。 在接收端,接收机(100)首先进行自相关处理,以找出在时域中同步的峰值。 然后,由于在接收机处已知多相码,所以在频域中计算每个子载波的信噪比并使用正态(高斯)分布进行平滑,以提供信道估计。 由于使用单个前同步码来处理同步和信道估计,所以这两个功能的开销显着降低。