頻率偏移下單載波分頻多重存取技術之不同等化方式比較

Comparisons of Four Equalization Methods for Single Carrier Frequency Division Multiple Access in the Presence of Carrier Frequency Offsets

黃俊豪(Chueh-Haw Huang)

指導教授 ： 劉宗憲

國立中正大學/工學院/通訊工程學系/碩士(2012年)

摘要

LTE (Long Term Evolution) 是3GPP 推出的未來4G 網路主流的技術, 在LTE
的網路資源存取技術, 3GPP 目前對LTE 的Downlink 採用Orthogonal Frequency-
DivisionMultipleAccess (OFDMA)技術, 而Uplink則是採用Single-Carrier Frequency-
Division Multiple Access (SC-FDMA) 的技術-FDMA 技術與OFDMA 不同之處為
SC-FDMA 有較低的峰均值功率比(Peak-to-Average Ratio, PAPR) 值, 以及分配
頻譜資源的方式;SC-FDMA 在分配頻譜資源時, 可分成連續式(Localized) 的LFDMA
與交織式(Interleaved) 的I-FDMA 兩種方式, 兩者間的Throughput 為LFDMA
較佳, I-FDMA 卻有較低的PAPR 值, 為考量Power Efficiency 及行動手持
裝置的一些資源限制, 通常我們會選擇連續分配頻譜(L-FDMA) 的方式-FDMA 相
較於OFDMA 雖然有較好的PAPR 值, 但在效能上的呈現卻不如OFDMA , 在對
頻率偏移(Carrier Frequency Offsets)上也較OFDMA更為敏感, 因此本論文探討各
種不同的等化方式[1][2]來改善SC-FDMA 效能, 也在頻率偏移(Carrier Frequency
Offsets) 下分析比較SC-FDMA 與OFDMA 所受的影響, 並參考[3]的方式來改善
頻率偏移對SC-FDMA 在效能上的影響。
關鍵詞- 單載波分頻多重存取技術, 頻率偏移, 功率峰值比, 子載波映射

關鍵字

單載波分頻多重存取技術 ； 功率峰值比

並列摘要

The 3GPP Long Term Evolution (LTE) is an industrial standard for wireless communication
to provide high-speed data transmission for mobile phones and data terminals.
LTE employs orthogonal frequency-division multiple access (OFDMA) for
downlink data transmission and single-carrier frequency-division multiple access (SCFDMA)
for uplink transmission. A prominent advantage of SC-FDMA over OFDMA
is that it’s transmit signal has a lower peak-to-average power ratio (PAPR). There are
two subcarrier allocation schemes for SC-FDMA systems, namely, the localized and
interleaved methods. The localized method has better performance than the interleaved
one, but the interleaved method has the lower peak-to-average power ratio than localized
method. Considering the power efficiency mobile phones, the LTE employs localized
method. Although SC-FDMA has the lower PAPR signals than OFDMA, it has
worse performance due to sensitivity to imperfect carrier frequency offset. This thesis
discusses different equalization methods to improve the performance of SC-FDMA
system and analyzes the performance of SC-FDMA system in the presence of carrier
frequency offset.
Keyword - Single-Carrier Frequency-DivisionMultipleAccess, Carrier Frequency Offsets,
Peak-to-Average Power Ratio, Subcarrier allocation

並列關鍵字

Single-Carrier Frequency-DivisionMultipleAccess ； Peak-to-Average Power Ratio

參考文獻

domain equalization in SC-FDMA systems,” IEEE International Conference on

[2] G. Huang, A. Nix, and S. Armour, ”Decision feedback equalization in SC-FDMA,”

large carrier frequency and timing offsets on the uplink,” in Proc. IEEE Global

Long Term Evolution. John Wiley Sons, Nov. 2008.

OFDM transmission using Hadamard transform, in Proc. IEEE Int. Conf. Commun.