全多工技術在無線通訊網路上之應用

Abstract

在現今無線網路中，低頻段使用越來越頻繁使得期可用資源越來越稀少。為了因應此問題，我們必須想辦法增加頻譜的使用效率，而全多工就是其中一個可能的選向來增加頻譜效率。在全多工技術下，一個無線網路節點能夠在同一頻率下同時傳送和接收，相對於傳統的半雙工技術是可以明顯的增加使用效率。 在這篇論文中，有三個不同的主題主要在研究如何運用全多工技術來增進無線網路效能。首先，我們將全多工技術運用在中繼傳輸上。相較於傳統半雙工中繼技術，全多工中繼點可以接收源點信號並同時傳送信號給目的點進而大幅增加系統效能。第二個主題則是將全多工技術運用在基地台上面使其能夠同時服務上行和下行使用者。但在這樣的環境下，上行使用者會對下行使用者造成干擾，因此我們提出方法解決此干擾來得到系統效能增益。最後，我們提出全多工中繼點的另一種使用方式。當有了全多工中繼點，基地台可以藉由全多工中繼點來服務隔壁基地台的用戶達到基地台間的負載平衡。

In today's wireless networks, spectrum is getting increasingly scarce. Full-duplex, then, is one possible candidate to improve the wireless networks' performance. When we introduce full-duplex capability into a node, it can transmit and receive at the same time and same frequency band, which sometimes we also call it 'in-band full-duplex'. In this thesis, I aim at exploiting the full-duplex capability to improve the performance of wireless communication networks. There are three different research topics in my thesis. First, I leverage the full-duplex ability on relay transmission. With full-duplex ability, relay can receive signal from source and forward signal to destination simultaneously. This property greatly enhances the efficiency of relay system compared to the half-duplex relay system, which needs to separate its operation into two phases, receiving first and then forwarding. Second, full-duplex can enable simultaneously uplink and downlink transmission. Hence, I introduce the ability into the access point (AP) in 802.11 networks. However, in such transmission, uplink client will interfere downlink client. To realize the full-duplex gain, we propose method to handle the inter-client interference. Finally, I exploit the usage of full-duplex relay to balance the asymmetric load in multi-cell networks. With full-duplex relay, a cell is possibly to help its adjacent cell's client to achieve the load balancing.