4G及後 4G通訊系統之新波形的研究

Abstract

第五代行動通訊網路(5th generation mobile network，5G)為滿足更彈性、多元化的服務需求，從超大行動寬頻(Extreme Mobile Broadband, eMBB)、巨量機器通訊(Massive Machine Type Communication, mMTC)、超可靠/低延遲通訊(Ultra-reliable Low Latency Communication, URLLC)三大使用者場景的服務需求制定相關技術標準。\n目前各國所制定的頻譜已不足以支援未來5G的服務，故向上尋求更高的頻段，例如與LTE-A重疊之6-10GHz，甚至是屬於極高頻的20-60GHz。4G使用正交頻多工的OFDM作為傳輸波形，在5G場景下，為因應新的頻段，ITU和3GPP都規劃採用非正交設計原理的新傳輸波形，雖然目前基於硬體設備技術及成本的限制，會採用CP-OFDM和DFT-s-OFDM為基礎來改進的波形，但在未來後5G的時代，F-OFDM、FBMC、UFMC、GFDM仍都是可能的候選波形。\n此外，5G時代將會有更多新增與截然不同的使用者場景。5G的整體傳輸系統為配合前後端軟體化的構想，提出以軟體主導服務的Network Slicing技術，以期更有彈性地實現不同使用需求。本研究擬以20-30GHz的mmWave為實驗頻段，同時以波形模擬器(SystemVue)測試並比較各個候選波形對應不同5G使用者場景的效能表現。最後，我們將三大場景適用之波形記錄並儲存於軟體定義網路(Software Defined Network，SDN)的交換器結點(Switch)，並結合網路功能虛擬化(Network Function Virtualization，NFV)技術，完成一個「以網路軟體化技術為基礎的類5G網路切片系統框架(Network Slicing Like System Framework based on Software Defined Networking for 5G)」。我們期望此一框架能從資料傳輸速率、延遲等方面滿足5G不同使用者場景之服務需求。

The fifth generation mobile network (5G) is designed to meet the needs of more flex-ible and diversified services such as extreme mobile broadband (eMBB), massive ma-chine type communication (mMTC), and ultra-reliable low latency communication (URLLC).\nThe spectrum used by the upcoming 5G services is not sufficient, therefore researches are looking to higher frequency bands, such as 6-10GHz overlapping with LTE-A, or even higher 20-60GHz which belongs to extremely high frequency.\n4G uses OFDM as the transmission waveform. For 5G scenarios, both ITU and 3GPP planed to use new transmission waveforms based on non-orthogonal technologies in response to the new frequency band. Currently, due to the limitation of infrastructure technic and its cost, the updated version of CP-OFDM and DFT-s-OFDM will be used for 5G. In the near future, the upcoming beyond 5G era, F-OFDM, FBMC, UFMC, GFDM are still some of the promising candidate waveforms.\nBesides, there will be more new and distinct user scenarios defined in 5G era. The overall 5G transmission system proposed the software-as -service network slicing technology to comply with software-based frontend and backend, in order to flexibly meet various user requirements.\nIn this study, the target spectrum of our experiment is 20-30GHz/30-40GHz of mmWave. We plan to use the waveform simulator, SystemVue, to test and compare the performance of each candidate waveform applied to different 5G user scenes.\nAt last, we record the most suitable waveforms for each of the three scenarios into the software-defined networking (SDN). We combine the result with the network func-tion virtualization (NFV) technology to establish a “Network Slicing Like System Framework based on Software Defined Networking for 5G”. We hope that this framework can meet the service needs of 5G different user scenarios in terms of data transmission rate and delay.