Comprehensive Performance Evaluation of Universal Time-Domain Windowed OFDM-Based LTE Downlink System
Comprehensive Performance Evaluation of Universal Time-Domain Windowed OFDM-Based LTE Downlink System
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基于通用时域加窗 OFDM 的 LTE 下行系统综合性能评估
DOI：
10.1587/transcom.2018ebp3242
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
H. Harada
中科院分区：
文献类型：
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作者：
Keiichi Mizutani;T. Matsumura;H. Harada
5G 及更高版本将支持各种全新系统，例如大规模机器类型通信 (mMTC) 系统。虽然每个mMTC设备占用的带宽相当窄，但大量的设备预计会产生大量的流量并消耗大量的频谱资源。因此，有必要主动收集和利用部分频谱资源，包括现有长期演进（LTE）系统受保护但未使用的保护频带。保护带最初是作为高带外发射 (OOBE) 的余量而确保的，该高带外发射 (OOBE) 是由基于循环前缀的正交频分复用 (CPOFDM) 中连续符号之间的不连续性引起的，并且已经广泛研究了能够实现高 OOBE 抑制的新波形，以有效地将窄带通信分配到频率间隙。时域加窗是一种众所周知的信号处理技术，用于以低复杂度减少 OOBE，而具有超过 CP 长度的长过渡持续时间的通用时域加窗 OFDM (UTW-OFDM) 已在基于 WLAN 的系统中证明了其能力。本文将UTW-OFDM应用于LTE下行系统，并在3GPP定义的信道模型下综合评估其性能。具体来说，我们通过计算机模拟评估 OOBE 减少和块错误率 (BLER)，并阐明在不降低通信质量的情况下可以将 OOBE 减少到什么程度。此外，我们通过计算所需乘法的数量来估计所提出的 UTW-OFDM、传统 CP-OFDM 和通用滤波 OFDM (UF-OFDM) 的实现复杂度。这些评估和估计结果表明，所提出的 UTW-OFDM 是一种适用于 5G 及更高版本的实用新波形。关键词: CP-OFDM, UTW-OFDM, 时域加窗, LTE, 带外发射 (OOBE), 误块率 (BLER), 复杂度
A variety of all-new systems such as a massive machine type communication (mMTC) system will be supported in 5G and beyond. Although eachmMTCdevice occupies quite narrow bandwidth, themassive number of devices expected will generate a vast array of traffic and consume enormous spectrum resources. Therefore, it is necessary to proactively gather up and exploit fractional spectrum resources including guard bands that are secured but unused by the existing Long Term Evolution (LTE) systems. The guard band is originally secured as a margin for high out-of-band emission (OOBE) caused by the discontinuity between successive symbols in the cyclic prefix-based orthogonal frequency division multiplexing (CPOFDM), and new-waveforms enabling high OOBE suppression have been widely researched to efficiently allocate narrowband communication to the frequency gap. Time-domain windowing is a well-known signal processing technique for reducing OOBE with low complexity and a universal timedomain windowed OFDM (UTW-OFDM) with a long transition duration exceeding the CP length has demonstrated its ability in WLAN-based systems. In this paper, we apply UTW-OFDM to the LTE downlink system and comprehensively evaluate its performance under the channel models defined by 3GPP. Specifically, we evaluate OOBE reduction and block error rate (BLER) by computer simulation and clarify how far OOBE can be reduced without degrading communication quality. Furthermore, we estimate the implementation complexity of the proposed UTW-OFDM, the conventional CP-OFDM, and the universal filtered-OFDM (UF-OFDM) by calculating the number of required multiplications. These evaluation and estimation results demonstrate that the proposed UTW-OFDM is a practical new-waveform applicable to the 5G and beyond. key words: CP-OFDM, UTW-OFDM, time-domain windowing, LTE, outof-band emission (OOBE), block error rate (BLER), complexity