無線多躍程中繼網路提供服務品質路由機制及連線排程之研究

QoS Routing and Link Scheduling in Wireless Multi-Hop Relay Networks

胡碩誠(Shuo-Cheng Hu) ； 李效謙(Hsiao-Chien Li)

《科學與工程技術期刊》 6卷2期 (2010/06) Pp. 27-38

https://doi.org/10.7117/JSET.201006.0027

摘要

無線多躍程中繼網路是由基地台(base station, BS)及中繼站(relay station, RS)所組成，藉由設置中繼站來增加無線網路涵蓋範圍具有建置成本低與容易建置的優點。中繼站將來自於使用者的資料封包傳送給連接有線網路的基地台（可能通過其他的中繼點）。兩個中繼點間不允許直接傳遞封包。一般認爲這樣的架構較其他無線網路架構（如無線網狀網路）更適合真實的佈建。
爲了滿足越來越多的即時性應用需求，如何在無線網路上提供服務品質保證一直是網路研究的重要課題。本研究藉由計算路徑干擾值的方式在無線多躍程中繼網路上求得以基地台爲樹根的樹狀路由，目標在於降低整體網路的干擾程度，提高連線的服務品質。在頻寬管理方面，我們提出了一個集中式連線排程以及一個階層式的連線排程機制。在階層式的連線排程機制中樹狀路由的每個節點（中繼站）可將來自子節點頻寬需求做可能的整合排程後，再回傳給基地台。如此，除了可以減輕使用集中式連線排程所帶給基地台的負荷外，中繼站也可以做到更有彈性的頻寬配置。依據實驗結果，本研究所提出的方法確實可以有效的增加網路傳輸量，提高頻寬的重複利用率。

關鍵字

無線多躍程網路 ； 服務品質 ； 干擾 ； 路由 ； 連線排程

並列摘要

A wireless multi-hop relay network consists of a base station plus various relay stations. The introduction of relay stations greatly extends the network coverage, to the benefit of users, and provides the salient advantages of lower implementation cost and easier system deployment. Relay stations transmit packets from (to) users toward (from) the base station, which is connected to a wired network. Unlike mesh networks, however, direct transmission between relay stations is not allowed. Therefore, wireless network architecture is more feasible for deployment in the real world.
For real-time applications, much research has been devoted to providing Qos guarantees in wireless networks. Accordingly, this report first proposes an interference-aware routing algorithm to construct a tree-based routing path rooted at the base station. The algorithm explores the least-interfering path to improve routing efficiency. For bandwidth management, we propose both centralized and hierarchical link scheduling mechanisms. In the latter, each node in the routing tree transmits its bandwidth request to the root, where potentially concurrent transmissions of descendents are combined to optimize data delivery. As a result, not only is the workload at the base station in the centralized link scheduling reduced considerably but the relay stations can also manage bandwidth in a flexible manner. Furthermore, the simulation results show that the proposed strategies can effectively improve overall network throughput and enhance frequency reuse. Thus, the performance evaluation indicates the usefulness of our development in actual practice.

並列關鍵字

multi-hop relay network ； QoS ； interference ； routing ； link scheduling