[資料來源:網(wǎng)絡]

Building a networked control system over wireless is a challenging task. The scarce spectrum imposes a fundamental
limit on the performance of the wireless channel.Random delays and packet losses are inevitable
建立網(wǎng)絡化的無線控制系統(tǒng)是一個極富挑戰(zhàn)性的任務。頻譜資源的稀缺對無線信道的工作性能帶來了很大的限制。隨機延滯和數(shù)據(jù)包丟失是不可避免的。

Even though this is true for any communication network, it
is much more pronounced in wireless networks due to limited spectrum and power, time-varying channel gains and interference.
盡管在任何通訊網(wǎng)絡中都會出現(xiàn)類似問題，但在無線網(wǎng)絡中，由于頻譜資源和功率的限制，以及隨時間變化的信道增益和干擾等原因，使這個問題顯得尤為突出。

Besides the design challenges in the link layer,multiple transmitter and receiver pairs need to share the channel and an efficient channel access mechanism needs to be designed.
除了數(shù)據(jù)鏈路層設(shè)計具有難度之外，由于多個發(fā)射機-接收機都需要共享該信道，因此還需要設(shè)計一個有效的信道接入機制。

As we shall see, random access without centralized control can waste a great deal of the scarce resources in the network.
我們應該看到，只有隨機接入而無集中控制，會浪費網(wǎng)絡中大量的稀缺資源。