封包無線網路(Packet Radio Network [ PRN] )對於支援移動及無線通訊是一個極具吸引力的架構。在這樣的網路架構下，雖然編碼分配(Code Assignment)的問題己經被廣泛的討論，但是我們發現在大多數的研究中，對於網路效能有重大影響的功率控制(Power Control)問題卻都被忽略了。所謂的功率控制指的是站台的傳輸範圍是可調整的。對於一個所有站台都己分配到編碼的PRN ，我們展示了如何在不違反原來編碼分的前題下，透過功率的調整來控制/改善網路的拓樸。數種不同的方法這裡被提出。透過模擬的方示，我們展示了雖然編碼分配的問題是NP-complete 且因此運算成本是非常昂貴地，但是使用我們的功率調整，只需要有限的成本就可增加約20%的網路效能。 The Packet Radio Network (PRN) is an attractive architecture to support mobile and wireless communication. Although the code assignment problem has been studied extensively on PRN, we observe in this paper that the power control problem has been ignored by most works, but may have signicant impact on performance. By power control, we mean that the transmission ranges of stations are tunable. We show given a PRN in which each host already received a code, how to adjust the powers of stations to control/improve thetopology of the PRN without violating the original code assignment. Several schemes are proposed. Through simulations, we demonstrate that although the code assignment problem is NP-complete and thus computationally very expensive, using our power adjustment schemes can easily improve the network performance by about 20% with polynomial costs.
