下世代前瞻無線通訊技術設計

Abstract

本論文致力於下世代前瞻無線通訊技術設計，其中下世代前瞻無線通訊系 統在本文中指的是第四代行動通訊技術之後的行動通訊技術。本文將點出在下世代前瞻無線通訊系統中的挑戰為何，並提出相對應的解決方法。首先，本文將介紹空間偏移調變，空間偏移調變是一個在近期提出的基頻調變技術，利用了天線的指標當作調變空間，並且因為其低硬體複查度的特性吸引了很多研究探討。可以說空間偏移調變是一個可能在下世代前瞻無線通訊中被採用的技術。然而，空間偏移調變的低頻譜效率是一個應當被注意的問題。其次，本文將探討由另一種方式來增加空間偏移調變的頻譜效率以及能量使用效率。第三，本文將探討另一個在下世代前瞻無線通訊系統中被廣為關注的問題，就是如何在頻分雙工系統中實現巨量多輸入多輸出。因為在頻分雙工巨量多輸入多輸出系統中，訓練(training)無線通道所需要的時間資源將超過無線通道的同調時間(channel coherence time)，這會令現有的傳輸模式無法正常運作，本文提出的設計致力於降低訓練無線通道所需要的時間資源。第四，本文將探討基地台網路維護問題，在基地台網路維護中，如何降低偵測覆蓋空洞所需的花費在下世代前瞻無線通訊中是一個重要的問題，本文將提出相對應的解決方法並對其驗證。

This thesis focuses on the advanced wireless communication techniques design for the Beyond fourth Generation of mobile phone mobile communications standards (B4G), where the new design challenges are elaborated and the corresponding solutions are given. First, the Space Shift Keying (SSK) is introduced; SSK is a recently-proposed baseband modulation technique employing antenna index as modulation alphabet, which attracts large research attentions for its low hardware complexity. As a result, SSK is a promising modulation for B4G wireless communications. However, the low spectral efficiency of SSK is a concern. Second, the corresponding designs for SSK are thus proposed to enhance the spectral efficiency and power efficiency in SSK. Third, the other apparent challenge for B4G is to implement massive Multiple-Input Multiple-Output (MIMO) system, and one of the challenges to implement massive MIMO in Frequency Division Duplexing (FDD) is the training for wireless channel. The temporal overhead to estimate the wireless channel in massive MIMO exceeds the channel coherence time, which makes wireless transmission impractical; the proposed design targets to reduce the training overhead for FDD massive MIMO. Fourth, for the network level coverage management, how to lower the cost in detecting coverage hole is a tough challenge in B4G; the corresponding solution is also proposed and verified in this thesis.