In this paper, a simplified differential amplitude demodulation scheme for high-level Differential Amplitude and Phase Shift Keying （DAPSK） techniqus is proposed, which requires fewer thresholds for demodulation and...In this paper, a simplified differential amplitude demodulation scheme for high-level Differential Amplitude and Phase Shift Keying （DAPSK） techniqus is proposed, which requires fewer thresholds for demodulation and thus has lower complexity. The performance of the Orthogonal Frequency Division Multiplexing （OFDM） system combined with the simplified DAPSK scheme is investigated over frequency-selective fading channels, then. Compared with coherent QAM-OFDM system, DAPSK-OFDM system has much lower complexity since channel estimation and equalization are unnecessary. Further more, under the condition of the same data rate, DAPSK-OFDM can achieve the performance close to or even better than that of QAM-OFDM system which adopts pilot symbols for channel estimation, by employing the concatenated code and utilizing the additional redundancy for outer coding at high Signal-to-Noise Ratios （SNRs）.展开更多
产生统计独立的多径衰落信道是无线信道仿真的一个基本问题。针对B3G-TDD系统中的频率选择性衰落信道提出了一种简单有效的仿真方法。该方法基于瑞利衰落信道的波普和比利(Pop and Beaulieu)模型建立,通过引入衰落指针,使多个瑞利衰落...产生统计独立的多径衰落信道是无线信道仿真的一个基本问题。针对B3G-TDD系统中的频率选择性衰落信道提出了一种简单有效的仿真方法。该方法基于瑞利衰落信道的波普和比利(Pop and Beaulieu)模型建立,通过引入衰落指针,使多个瑞利衰落信道彼此独立,并为每个瑞利衰落信道分配不同的时延。仿真结果表明,设计出的频率选择性衰落信道不仅简单而且符合信道特点。运用该方法研究了BPSK信号通过瑞利衰落信道和频率选择性衰落信道以后的误码率情况并进行了比较,提出正交频分复用技术作为改善信道衰落的有效方法。B3G-TDD系统中信道估计的实验结果表明,这种方法是高效而且可行的。展开更多
As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next...As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications. The symbols detection problem of the V-BLAST OFDM system is investigated under the frequency-selective fading environment. The joint space-frequency demultiplexing operation is proposed in the V-BLAST OFDM system. Successively, one novel half-rate rotational invariance joint space-frequency coding scheme for the V-BLAST OFDM system is proposed. By elegantly exploiting the above rotational invariance property, we derive one direct symbols detection scheme without knowing channels state information (CSI) for the frequency-selective V-BLAST OFDM system. Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct symbols detection scheme.展开更多
提出了一种正交频分复用(orthogonal frequency division multiplex,OFDM)技术与协作复数域网络编码有机结合的OFDM-协作复数域网络编码(OFDM-cooperative complex field network coding,OFDM-CCFNC)算法。理论分析了该算法的系统误帧...提出了一种正交频分复用(orthogonal frequency division multiplex,OFDM)技术与协作复数域网络编码有机结合的OFDM-协作复数域网络编码(OFDM-cooperative complex field network coding,OFDM-CCFNC)算法。理论分析了该算法的系统误帧率和频谱利用率,仿真结果表明,该算法能够克服无线信道的频率选择性衰落影响,提高系统频谱利用率。另外,基于最小化系统误帧率给出了该算法下的一种最优系统功率分配策略。展开更多
基金This workis supported by National"863"High Technology Projects of China (G1999035804) .
文摘In this paper, a simplified differential amplitude demodulation scheme for high-level Differential Amplitude and Phase Shift Keying （DAPSK） techniqus is proposed, which requires fewer thresholds for demodulation and thus has lower complexity. The performance of the Orthogonal Frequency Division Multiplexing （OFDM） system combined with the simplified DAPSK scheme is investigated over frequency-selective fading channels, then. Compared with coherent QAM-OFDM system, DAPSK-OFDM system has much lower complexity since channel estimation and equalization are unnecessary. Further more, under the condition of the same data rate, DAPSK-OFDM can achieve the performance close to or even better than that of QAM-OFDM system which adopts pilot symbols for channel estimation, by employing the concatenated code and utilizing the additional redundancy for outer coding at high Signal-to-Noise Ratios （SNRs）.
文摘产生统计独立的多径衰落信道是无线信道仿真的一个基本问题。针对B3G-TDD系统中的频率选择性衰落信道提出了一种简单有效的仿真方法。该方法基于瑞利衰落信道的波普和比利(Pop and Beaulieu)模型建立,通过引入衰落指针,使多个瑞利衰落信道彼此独立,并为每个瑞利衰落信道分配不同的时延。仿真结果表明,设计出的频率选择性衰落信道不仅简单而且符合信道特点。运用该方法研究了BPSK信号通过瑞利衰落信道和频率选择性衰落信道以后的误码率情况并进行了比较,提出正交频分复用技术作为改善信道衰落的有效方法。B3G-TDD系统中信道估计的实验结果表明,这种方法是高效而且可行的。
文摘As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications. The symbols detection problem of the V-BLAST OFDM system is investigated under the frequency-selective fading environment. The joint space-frequency demultiplexing operation is proposed in the V-BLAST OFDM system. Successively, one novel half-rate rotational invariance joint space-frequency coding scheme for the V-BLAST OFDM system is proposed. By elegantly exploiting the above rotational invariance property, we derive one direct symbols detection scheme without knowing channels state information (CSI) for the frequency-selective V-BLAST OFDM system. Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct symbols detection scheme.
文摘提出了一种正交频分复用(orthogonal frequency division multiplex,OFDM)技术与协作复数域网络编码有机结合的OFDM-协作复数域网络编码(OFDM-cooperative complex field network coding,OFDM-CCFNC)算法。理论分析了该算法的系统误帧率和频谱利用率,仿真结果表明,该算法能够克服无线信道的频率选择性衰落影响,提高系统频谱利用率。另外,基于最小化系统误帧率给出了该算法下的一种最优系统功率分配策略。
