Impact of timing jitter on the performance of carrier amplitude and phase modulation
Impact of timing jitter on the performance of carrier amplitude and phase modulation
复制标题
定时抖动对载波幅度和相位调制性能的影响
DOI：
10.1109/icsae.2016.7810199
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
W. Popoola
中科院分区：
文献类型：
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作者：
Kabiru O. Akande;W. Popoola
载波幅度和相位调制（CAP）是一种高频谱效率的多电平调制方案，以其实现简单而闻名，因为它提供了一种低复杂度的方法来提高频谱效率和系统吞吐量。这些特性已经看到CAP被实现为众所周知的离散多音（DMT）的替代方案。然而，CAP对定时抖动的敏感性很高，这是由于其使用脉冲整形，这消除了在其收发器架构中对载波调制和载波频率恢复的需要。本文研究了定时抖动对CAP技术性能的影响。结果表明，随着定时抖动的增加，CAP-4的误比特率（BER）性能下降，当定时抖动（τ）达到码元持续时间T的20%时，CAP-4的BER性能达到错误平层。虽然观察到定时抖动效应随着滚降因子α的增加而减小，但由此产生的性能下降随着数据星座大小的增加而增加。在0.02T的定时抖动下，具有64个数据星座点（CAP-64）和0.15滚降因子的CAP在2 × 101的BER下达到错误平层。本文的结果表明，虽然CAP提供实现简单，定时同步是一个关键的要求，在其接收机设计。
Carrier amplitude and phase modulation (CAP) is a highly spectral-efficient multilevel modulation scheme renowned for its implementation simplicity as it offers a low complexity approach to increase spectral efficiency and system throughput. These characteristics has seen CAP being implemented as an alternative to the well-known discrete multitone (DMT). However, the sensitivity of CAP to timing jitter is high due to its use of pulse shaping which eliminate the need for carrier modulation and carrier frequency recovery in its tranceiver architecture. In this paper, the impact of timing jitter on the performance of CAP technique is investigated. It is shown that with increasing timing jitter, the bit error rate (BER) performance of CAP-4 degrades and reaches an error floor when the timing jitter (τ) reaches 20% of the symbol duration, T. Although the timing jitter effect is observed to reduce with increasing roll-off factor, α, the resulting performance degradation increases with the data constellation size. With a 0.02T timing jitter, CAP with 64 data constellation points (CAP-64) and 0.15 roll-off factor reaches an error floor at a BER of 2 × 101. The results of this paper show that although CAP offer implementation simplicity, timing synchronization is a critical requirement in its receiver design.