在無線感測網路中，由空洞所引起的『local minimum phenomenon』是geographic greedy forwarding時常要面對的一個重要挑戰。如今，多數現存的繞洞研究傾向於將資料封包沿著空洞或禁止區域的周圍傳送。這樣的設計會導致空洞與禁止區域周圍的感測節點比其他感測節點更快用盡它們的電量，擴大洞的大小並縮短網路生命週期。在本篇論文中，我們提出一個能量有效避洞繞徑協定(HARP)來處理在無線感測網路環境下的這個問題。我們在空洞的周圍建立延展區域來減輕繞徑封包時空洞外圍感測節點的能量消耗。此外，我們也考慮多洞的環境，不會為了避洞而捨棄選擇在洞之間的較短路徑。實驗結果顯示我們的協定在網路生命週期上有較好的執行結果。

In wireless sensor networks, an important challenge often faced in geographic greedy forwarding is the “local minimum phenomenon” which is caused by holes. Nowadays, most existing research works for bypassing holes tend to route data packets along the perimeter of holes or forbidden regions. Such a scheme causes the boundary nodes on the perimeter of holes and forbidden regions exhaust their energy faster than others, thus enlarging the hole sizes and shortening the network lifetime. In this paper, we propose an energy efficient Hole Avoiding Routing Protocol (HARP) to address this problem in wireless sensor networks. We establish expanded areas encircling the hole for mitigating load of boundary nodes when routing packets. Besides, we also consider multi-hole environment, do not discard a choice of shorter path that passes through between holes in order to dodge holes. The experimental result shows that our protocol achieves better performance in network lifetime.

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