Puncturing is the predominant strategy to construct high code rate turbo codes. Puncturing period is a crucial parameter influencing the performance of punctured turbo codes (PTC). Here we developed a new puncturing s...Puncturing is the predominant strategy to construct high code rate turbo codes. Puncturing period is a crucial parameter influencing the performance of punctured turbo codes (PTC). Here we developed a new puncturing scheme of turbo codes, with which the puncturing period on the performance of PTC is studied. Consequently, suggestions on selecting the puncturing period are proposed.展开更多
This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous work...This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous works on this topic, the present development and the performance analysis as well, is based on rate compatible punctured turbo codes. Rate compatibility provides incremental redundancy in transmission of parity bits for error correction at the data link layer. Turbo coding and iterative decoding gives lower packet error rate values in low signal-to-noise ratio regions of the adaptive modulation and coding (AMC) schemes. Thus, the applied cross-layer design results in AMC schemes can achieve better spectral efficiency than convolutional one while it retains the QoS requirements at the application layer. Numerical results in terms of spectral efficiency for both turbo and convolutional rate compatible punctured codes are presented. For a more comprehensive presentation, the performance of rate compatible LDPC is contrasted with turbo case as well as the performance complexity is discussed for each of the above codes.展开更多
Coding techniques have always been a major area of scientific interest. Due to this interest, many coding schemes were invented. Eventually, their implementation in various systems contributed in the evolvement of Wir...Coding techniques have always been a major area of scientific interest. Due to this interest, many coding schemes were invented. Eventually, their implementation in various systems contributed in the evolvement of Wireless Communications. A breakthrough was definitely Turbo coding. Particularly, the concept of joining two or more convolutional encoders in parallel (PCCC) or in serial (SCCC), along with the iterative decoding technique, literally raised the expectations of the anticipated BER performance. In fact, Concatenated Convolutional Codes clearly outperform convolutional codes. Moreover, various systems, either under development or either for future use, will have high standards. The previous systems should present exceptional tolerance of noise effects and consequently a low overall number of received errors. For this purpose a new PCCC design was developed. The system’s performance analysis, using an AWGN channel, showed better results for various iterations compared to other schemes such as typical PCCC, SCCC and finally a Convolutional encoder with a Viterbi decoder.展开更多
Turbo码已被广泛应用于第三代移动通信技术(3rd Generation mobile communication technology,3G)、第四代移动通信技术(4th Generation mobile communication technology,4G)等通信系统中.为了提高信道编码效率,在Turbo码的实际应用中...Turbo码已被广泛应用于第三代移动通信技术(3rd Generation mobile communication technology,3G)、第四代移动通信技术(4th Generation mobile communication technology,4G)等通信系统中.为了提高信道编码效率,在Turbo码的实际应用中常结合删余技术.由于部分校验位的缺失,删余Turbo码的盲识别难度更高,且目前针对删余Turbo码的交织识别研究较少.本文在删余Turbo码的随机交织器识别中,基于对数符合度的概念,提出利用软输出维特比算法(Soft Output Viterbi Algorithm,SOVA)对后验信息进行更新以辅助识别,从而弥补对数符合度的近似计算所导致的性能损失.仿真结果表明:与现有的相关算法相比,本文算法具有更好的性能;加之对数符合度和SOVA两者的计算复杂度均相对较低,所以本文算法也具备较高的实时性.展开更多
文摘Puncturing is the predominant strategy to construct high code rate turbo codes. Puncturing period is a crucial parameter influencing the performance of punctured turbo codes (PTC). Here we developed a new puncturing scheme of turbo codes, with which the puncturing period on the performance of PTC is studied. Consequently, suggestions on selecting the puncturing period are proposed.
文摘This paper extends the work on cross-layer design which combines adaptive modulation and coding at the physical layer and hybrid automatic repeat request protocol at the data link layer. By contrast with previous works on this topic, the present development and the performance analysis as well, is based on rate compatible punctured turbo codes. Rate compatibility provides incremental redundancy in transmission of parity bits for error correction at the data link layer. Turbo coding and iterative decoding gives lower packet error rate values in low signal-to-noise ratio regions of the adaptive modulation and coding (AMC) schemes. Thus, the applied cross-layer design results in AMC schemes can achieve better spectral efficiency than convolutional one while it retains the QoS requirements at the application layer. Numerical results in terms of spectral efficiency for both turbo and convolutional rate compatible punctured codes are presented. For a more comprehensive presentation, the performance of rate compatible LDPC is contrasted with turbo case as well as the performance complexity is discussed for each of the above codes.
文摘Coding techniques have always been a major area of scientific interest. Due to this interest, many coding schemes were invented. Eventually, their implementation in various systems contributed in the evolvement of Wireless Communications. A breakthrough was definitely Turbo coding. Particularly, the concept of joining two or more convolutional encoders in parallel (PCCC) or in serial (SCCC), along with the iterative decoding technique, literally raised the expectations of the anticipated BER performance. In fact, Concatenated Convolutional Codes clearly outperform convolutional codes. Moreover, various systems, either under development or either for future use, will have high standards. The previous systems should present exceptional tolerance of noise effects and consequently a low overall number of received errors. For this purpose a new PCCC design was developed. The system’s performance analysis, using an AWGN channel, showed better results for various iterations compared to other schemes such as typical PCCC, SCCC and finally a Convolutional encoder with a Viterbi decoder.
文摘Turbo码已被广泛应用于第三代移动通信技术(3rd Generation mobile communication technology,3G)、第四代移动通信技术(4th Generation mobile communication technology,4G)等通信系统中.为了提高信道编码效率,在Turbo码的实际应用中常结合删余技术.由于部分校验位的缺失,删余Turbo码的盲识别难度更高,且目前针对删余Turbo码的交织识别研究较少.本文在删余Turbo码的随机交织器识别中,基于对数符合度的概念,提出利用软输出维特比算法(Soft Output Viterbi Algorithm,SOVA)对后验信息进行更新以辅助识别,从而弥补对数符合度的近似计算所导致的性能损失.仿真结果表明:与现有的相关算法相比,本文算法具有更好的性能;加之对数符合度和SOVA两者的计算复杂度均相对较低,所以本文算法也具备较高的实时性.
