2023年全國(guó)碩士研究生考試考研英語(yǔ)一試題真題(含答案詳解+作文范文)_第1頁(yè)
已閱讀1頁(yè),還剩10頁(yè)未讀, 繼續(xù)免費(fèi)閱讀

下載本文檔

版權(quán)說(shuō)明:本文檔由用戶(hù)提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)

文檔簡(jiǎn)介

1、See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/224182170Design and Implementation of a ParallelTurbo-Decoder ASIC for 3GPP-LTEARTICLE in IEEE JOURNAL OF SOL

2、ID-STATE CIRCUITS · FEBRUARY 2011Impact Factor: 3.11 · DOI: 10.1109/JSSC.2010.2075390 · Source: IEEE XploreCITATIONS32DOWNLOADS405VIEWS2024 AUTHORS, INCLUDING:Christoph StuderCornell University86 PUBLICATI

3、ONS 873 CITATIONS SEE PROFILEAvailable from: Christoph StuderRetrieved on: 16 June 20152 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 46, NO. 1, JANUARY 2011Fig. 1. Left: parallel-concatenated turbo-encoder. Right: sim

4、plified block-diagram of a turbo-decoder.Fig. 2. Left: radix-2 forward state-metric recursion for two trellis-steps. Right: radix-4 forward state-metric recursion.over the wireless channel. In the receiver, a soft-output

5、 detector computes reliability information in the form of log-likelihood ratios (LLRs) for the transmitted bits , and [8]; the resulting LLRs , and indicate the probability of the corresponding bits being a binary 1 or 0

6、.A. Turbo-Decoding AlgorithmDecoding of turbo-codes is usually performed with the algo- rithm proposed in [8]. The main idea is depicted on the right- hand side (RHS) of Fig. 1 and amounts to iteratively exchanging extri

7、nsic LLRs and between the two SISO decoders (SDs) to improve the error-rate performance successively. The first and second SD perform decoding of the convolutional code generated by the first or the second CE, respective

8、ly. One pass by both the first and the second SD is referred to as a full-iter- ation; the operation performed by a single SD a half-iteration. The total number of full-iterations for each code block is de- noted by (e.g

9、., 11 half-iterations correspond to ). Each SD computes intrinsic a-posteriori LLRs and , for the transmitted bits, based on the systematic LLRs in naturalor interleaved order , on the parity LLRs or ,and on the so-calle

10、d a-priori LLRs or . For the first half-iteration, the a-priori LLRs are set to zero (i.e.,, ). In subsequent iterations, each SD uses the extrinsic LLRs computed by the other SD in the previous half-iteration as a-prior

11、i LLRs, i.e.,and (see Fig. 1). After a givennumber of half-iterations, the turbo-decoder generates estimates for the information bits based on the sign of the intrinsic LLRs.B. Radix-4 Max-Log M-BCJR AlgorithmThe maximum

12、 a-posteriori (MAP) SISO decoding algorithm developed by Bahl, Cocke, Jelinek, and Raviv (BCJR) [9] forms the basis of the SD used in this work. The BCJR algorithm re- sembles the Viterbi algorithm [10] and traverses a t

13、rellis rep- resenting the convolutional code to compute the intrinsic LLRs. Fig. 2 shows such a trellis, with nodes corresponding to the states of the CEs and branches indicating admissible state- transitions. Each trans

14、ition from a state (trellis-step ) to (trellis-step ) is associated with a branch-metric(refer to [11], [12] for details). The BCJR algorithm in its orig- inal form is impractical due to large memory requirements and the

15、 computation of transcendental functions. We adopt an ap- proximate algorithm [11], [13], as briefly described below. 1) Max-Log Approximation: The BCJR algorithm traverses the trellis in both forward and backward direct

16、ions to compute the state-metrics and recursively for all eight states. To avoid transcendental functions, we apply the max-log ap- proximation to the forward state-metric recursions [11](1) where and correspond to the t

溫馨提示

  • 1. 本站所有資源如無(wú)特殊說(shuō)明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
  • 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶(hù)所有。
  • 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁(yè)內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒(méi)有圖紙預(yù)覽就沒(méi)有圖紙。
  • 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
  • 5. 眾賞文庫(kù)僅提供信息存儲(chǔ)空間,僅對(duì)用戶(hù)上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶(hù)上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
  • 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
  • 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶(hù)因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。

最新文檔

評(píng)論

0/150

提交評(píng)論