標題: | 廣義的機會式通訊---無線行動網路中之競爭、合作與感知---子計畫一:感知無線行動網路之頻譜偵測與管理 Spectrum Sensing and Management in Cognitive Wireless Mobile Notworks |
作者: | 蘇育德 SU YU TED 國立交通大學電信工程學系(所) |
關鍵字: | 無線通訊;頻譜偵測;協力通訊;感知無線電;無線電資源管理;cognitive radio;cooperative communications;radio resource management;spectrum estimation;wireless communication |
公開日期: | 2008 |
摘要: | 近年來興起的感知無線電開啟許多新的無線通訊可能性,一般認為將是下一代無線 行動網路的新技術典範。感知無線電技術之所以被廣泛的研究是因為其具有偵測周圍環 境無線通訊資源現況(即那些資源如頻段等是可供信號的傳送或接收)的能力,並可因 應現況作最適當的波形調整(例如: 調整訊號頻寬、訊號波形、載波頻率、調變種類、功 率及傳輸方向等)以達到有效率的使用無線通訊資源並同時獲致最佳的效能表現。另一 新興的無線傳輸技術則是所謂的協力式通訊(Cooperative Communications)。這種通訊 方式藉由週遭暫時閒置的通訊傳收機的協助來合力一起傳收信號,因此可視為另外一種 機會式(opportunistic)無線通訊空間資源的感知與利用。事實上,除了信號的傳收之外, 感知無線電對環境的感測與瞭解也可透過多個在不同位置傳收機的合作來提升其感測 與瞭解的能力。我們可以說,感知無線電與協力式通訊是廣義機會式通訊不同面貌的呈 現。這種廣義機會式通訊的具體實現之一就是所謂的感知(無線電為基礎的)無線行動 網路(cognitive radio based wireless mobile networks, or cognitive wireless mobile networks)。在現有無線通訊資源有限傳輸需求卻日增的情形下,廣義機會式通訊能爭取 新的資源並有效的動態運用所有資源,的確是十分值得且需要深入探討的新領域。 本子計畫目的即在開發(一)各式感知無線電技術中的頻譜感測(spectrum sensing) 機制與其性能評析,(二)感知無線電系統的無線電資源管理(radio resource managements) 演算法、規約與性能分析-讓無線電資源的分配與管理,能因時因地因裝置的不同而有 效地管理調整。盡量排除局部性(local)的最佳解,尋求全域(global)的最佳解,以及(三) 感知無線電系統的感知無線電傳輸(cognitive radio transmission)。同時我們亦將搭配其 他子計畫的研究成果,以跨層(cross layer)設計的方式,達到整體系統性能最佳化。 以下,我們分別簡述未來三年的研究重點。 第一年重點為頻譜感測(spectrum sensing)機制與其性能評比分析。由於頻譜感測部 分的性能是影響到感知無線電系統性能表現的主要關鍵,與其他子計畫所探討的感知協 力通訊等議題息息相關。在此子計畫中,我們將針對頻譜感測部分提出新型的軟式協力 偵測演算法,其中我們將對因主用戶不使用、或主用戶無法使用所造成的閒置頻譜提出 低複雜度且偵測準確機率高的頻譜感測機制。這裡「頻譜」包含了廣義信號空間的所有 維度,而不只是傳統的頻域分佈而已。 第二年的重心將是感知無線電系統的無線電資源管理(radio resource managements) 演算法、規約之設計與性能分析。我們延續第一年的研發成果,在計畫的第二年著手對 頻譜感測獲得的無線電資源進行特性分析,提出合理的競爭機制,並進一步研究資源分 配,建議最佳或次佳但低複雜度的頻譜資源分配演算法。這些資源包含頻段、功率(能 量)、協力傳收點等。我們將同時引進賽局理論(game theory)的概念以分析這種既協力又 競爭的通訊規約之理論容量、能量或功率使用效率等相關性能。此部分將需與子計畫二 與子計畫四相互配合。 第三年 -感知無線電傳輸技術 在此計畫的最後一年,我們將完成感知無線電網路中之感知無線傳收子系統設計。 我們的重點是各個感知無線電裝置在得知週遭環境的資訊,並被分配到一定的無線電資 源之後如何設計實際的實體層傳輸波形(基頻波形、調變、編碼、天線波束等)及接收 技術作深入的研發與探討。此部分亦將需與子計畫二的研發技術相互配合。 Cognitive radio (CR) technology has in recent years emerged as a new communication paradigm for next generation wireless mobile networks. It promises much more efficient radio resource (especially electromagnetic spectrum) utilization, improved system performance and novel new functionalities. The main theme of CR is the capability of a radio to sense and adapt to its environment, constantly making spectrum, transmission and networking decisions that optimize radio resources (energy/power, spectrum, cooperative nodes etc.) opportunistically. Another rising paradigm is the so-called cooperative communications. In a cooperative communication network, a terminal would solicit cooperation from surrounding terminals for transmitting or receiving signals, which means it exploits additional spatial radio resources (in this case, temporary idled terminals) to enhance system performance. Note that a CR can also improve its environmental (spectrum in particular) sensing capability through cooperation with other terminals. Hence both CR and cooperative communications can be regarded as parts of the generalized opportunistic communications and one of its realizations is the class of cognitive (radio-based) wireless mobile networks. The purpose of this subproject is to analyze and develop spectrum sensing schemes in various operation scenarios and investigate key elements of the other two phases of a cognitive cycle, namely spectrum analysis and spectrum (management decisions). We refer to the term 「spectrum」 in a generalized sense so that it includes all (generalized) signal dimensions, e.g., conventional frequency spectrum, available time slots, non-interfering antenna direction, cooperative nodes, etc. We shall study radio resource management decisions that maximize network capacity with minimum energy consumption and perhaps with certain delay bound constraint. Reasonable or near optimal competition and cooperation mechanisms shall be suggested and their behaviors and effectiveness be evaluated. Finally, based on the given radio resource, we shall design practical cognitive communication waveforms and detection schemes that achieve or approach the theoretical performance limits. These efforts shall need inputs from and will collaborate with other subprojects. We expect very close interactions amongst all subprojects, as has been stated in the main project. |
官方說明文件#: | NSC96-2221-E009-076-MY3 |
URI: | http://hdl.handle.net/11536/102201 https://www.grb.gov.tw/search/planDetail?id=1598698&docId=274590 |
Appears in Collections: | Research Plans |