OFDM系統(tǒng)雙選擇性慢衰落信道的壓縮感知估計(jì)
doi: 10.11999/JEIT140247 cstr: 32379.14.JEIT140247
基金項(xiàng)目:
國(guó)家自然科學(xué)基金(61372122)和江蘇省普通高校研究生科研創(chuàng)新計(jì)劃 (CXZZ11-0397)資助課題
Compressed Sensing Based on Doubly-selective Slow-fading Channel Estimation in OFDM Systems
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摘要: 為了增強(qiáng)壓縮感知框架里Sl0(Smoothedl0-norm)重構(gòu)算法的抗噪性能，該文在其目標(biāo)函數(shù)里添加一個(gè)誤差容允項(xiàng)，并提出了一種改進(jìn)型重構(gòu)算法l2-Sl0(Smoothed l0-norm regularized least-square)。另外通過(guò)對(duì)多徑信道的時(shí)延和多普勒頻移參數(shù)構(gòu)成的時(shí)頻2維有界區(qū)域進(jìn)行量化，將OFDM時(shí)頻雙選擇性慢衰落信道估計(jì)問(wèn)題建模為壓縮感知理論中的稀疏信號(hào)重構(gòu)問(wèn)題，提出了一種采用l2-Sl0估計(jì)信道時(shí)頻參數(shù)的方法。仿真結(jié)果表明在相同的噪聲環(huán)境里，l2-Sl0的重構(gòu)性能優(yōu)于Sl010 dB左右；運(yùn)用l2-Sl0的信道估計(jì)方法可獲得接近于理想最小二乘法的估計(jì)性能，且該方法在低信噪比的場(chǎng)景里也能獲得較高的估計(jì)準(zhǔn)確度。
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關(guān)鍵詞:
- 壓縮感知 /
- OFDM /
- 慢時(shí)變信道 /
- 信道估計(jì)
Abstract: In order to improve the reconstruction accuracy of smoothed l0-norm (Sl0) algorithm in the presence of noise, a modified algorithm named smoothed l0-norm regularized least-square (l2-Sl0) is proposed in this paper, which permits a small perturbation. Further, through placing a finite grid in the planar time-frequency bounded region, the problem of doubly-selective slow-fading channel estimation in OFDM system is modeled as the problem of sparse signal reconstruction in compressed sensing framework, and then thel2-Sl0 algorithm is applied to reconstruct the channel parameters. A number of computer-simulation-based experiments show that reconstruction accuracy of thel2-Sl0 algorithm is improved by approximately 10 dB as compared with theSl0 algorithm in the presence of noise. The performance of the proposed doubly-selective slow-fading channel estimation method usingl2-Sl0 algorithm is nearly close to that of the ideal Least Square (ideal-LS) method. Moreover, the proposed method has higher estimation uccuracy well in the case of low SNR.-
Key words:
- Compressed sensing /
- OFDM /
- Slow time-varying channel /
- Channel estimation
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