軟體無線電（Software-Defined Radio，簡稱SDR）技術系以軟體取代無線通訊節點中的部份硬體，使得通訊設備可以藉由軟體更新來改變其運作模式。但若在軟體下載過程中產生錯誤，則部份節點將無法正確收到更新之軟體，此時將產生網路分割（Network Partition）的問題。因此，在可重組網路（Reconfigurable Network）中，如何可靠的下載軟體到網路中的每個節點，是個重要的研究議題。直接使用諸如簡單式洪氾法（Simple Flooding）與修正式洪氾法（Modified Flooding）似乎可行，也符合直覺。然而，簡單式洪氾法會產生十分可觀的封包量，以致於浪費許多寶貴的頻寬資源。而修正式洪氾法封包量雖可以少一點，但其擊中率（Hit Rate）卻不高，無法讓網路中的所有節點都能正確收到軟體，造成網路分割的現象。為了正確的更新網路中所有節點的軟體，同時減少網路無謂的多餘封包，我們在這篇論文中提出兩種可靠的軟體下載機制。而為了配合不同的應用需求，本論文設計兩種由洪氾協定（Flooding Protocol）修改而來的機制，分別為限制洪氾式軟體下載（Controlled Flooding Software Download，簡稱CFSD）機制以及自由訂閱式軟體下載（Advertising and Subscribing Software Download，簡稱ASSD）機制。這兩種機制都屬於非集中式架構，而且會利用重傳機制以及確認回條，來減少無謂的封包量，並可保証所有節點皆可正確的更新軟體。由模擬結果顯示，CFSD機制與ASSD機制的擊中率要比修正式洪氾法高10%，且封包數僅有簡單式洪氾法的0.9%。

The Software-Defined Radio (SDR) technology provides software control of communication functions and thus communication devices can be reconfigured during their working mode by upgrading the software. When error occurs during software downloading, some nodes may not receive the software correctly. If so, the reconfigurable network will be partitioned. In a reconfigurable network, it is an important issue to download software for each node correctly.
The simple flooding and the modified flooding schemes are intuitive methods for delivering software to each node in a reconfigurable network. The former causes a lot of overheads and wastes a lot of bandwidth, therefore, it not suitable to be applied in resource-limited wireless networks. The latter has low overhead but loses reliability, some nodes may not receive the software correctly because the hit rate is only 90 % when the modified flooding scheme is used. However, the partition problem occurs when the modified flooding scheme is used. In order to achieve high reliability and reduce unnecessary packets, we propose two reliable software download schemes, the Controlled Flooding Software Download (CFSD) and Advertising and Subscribing Software Download (ASSD) schemes. These two schemes use the decentralized architecture and are designed for different applications. Retransmission is used to retain the hit rate and confirmation message is used to reduce unnecessary overhead. Simulation results show that the hit rate of the CFSD, the ASSD and simple flooding schemes is 10% higher than that of the modified flooding scheme. And the overhead in the CFSD, the ASSD and the modified flooding schemes is about 99% lower than that of the simple flooding scheme.

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