shannon capacity 中文意思是什麼
shannon capacity
解釋
香農容量-
Turbo code was introduced by c. berrou in 1993. turbo code can achieve the error correcting capacity close to the shannon - limit with reasonable decoding complexity, provided that the code words are long enough
1993年， c . berrou提出了一種新的通道編碼方案? ? turbo碼， turbo碼能夠在編碼長度較長的情況下得到接近香農極限的糾錯性能。 -
Such code is also called gradually good code or shannon code. in 1993, c. berro etc. firstly proposed a new channel code method - turbo code, which employed recursive systematic code 、 the random interleaver 、 map ( maximum a posteriori ) algorithm and iterative decoding algorithm obtained the capacity that had only 0. 7db difference compared to the shannon limitation
1993年c . berro等首先提出了一種全新的通道編碼方式? turbo碼，採用遞歸系統碼與隨機交織器構造turbo碼，並將map （ maximumaposteriori ）演算法和迭代演算法應用於解碼過程，獲得了與香農理論極限僅差0 . 7db的性能。 -
Low density parity check ( ldpc ) codes are good error - correcting codes, which can approach shannon ' s capacity limit. due to the sparsity of its check matrix, ldpc codes can be decoded only with linear time complexity using iterative decoding algorithm. therefore, ldpc codes have become one of the most attractive fields in the channel coding community
低密度校驗碼是一種逼近香農限的好碼，由於其校驗矩陣的稀疏特性，採用迭代譯碼演算法，它的譯碼僅具有線性時間復雜度，所以目前ldpc碼己成為通道編碼理論界的研究熱點之一。 -
Based on these advantages we analyze the performance of constant - power variable - rate m - qam schemes for spectrally efficient data transmission over nmf channels. by introducing the adaptive modulation approach, we gain two things : 1 ) the error rate is kept at a constant level. 2 ) the achievable spectral efficiency comes within 5 db of the shannon capacity limit. at the last chapter, the presentation of a single base station and a single mobile scenario proved the feasibility of adaptive schemes
然後作者的精力轉入通道的自適應方案的研究中，首先通過研究發現nakagami衰落因子的適當調整可以近似於常見的瑞利衰落和萊斯衰落，接著研究在無線通道中採用三種不同自適應方案時的通道容量，研究表明速率的調整是增加通道容量的關鍵，在此基礎上，著重研究了離散變速率qam的情況，表明這種調制方案無論在頻帶利用率還是在系統平均誤碼率比其它情況提高很多。 -
Low - density parity - check code ( ldpc codes ) is a kind of asymptotic good codes that can approach shannon ' s capacity with low complexity iterative decoding
基於圖模型的ldpc碼是一種有較低的迭代譯碼復雜度和接近shannon容量限的漸近好碼。 -
The channel capacity of awgn channel and rayleigh fading channel with binary input and continuous output are derived and the shannon capacity limits for different code rate are provided. 2
對二元輸入、連續輸出的awgn通道和rayleigh衰落通道的通道容量進行了推導，給出了不同碼率下的shannon容量限。 -
Designing codes with approaching shannon ' s capacity performance and low coding and decoding complexity is a challenging and meaningful issue in channel coding field
設計性能逼近通道容量、編譯碼復雜度較低的實用好碼是通道編碼領域中最重要的工作之一。
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