為了簡化全互連環境飽和情況下IEEE 802.11DCF的性能分析方法，采用了一種簡單的盒子－球模型。研究了將活躍結點發送報文時的碰撞轉換成對相同數目的球獨立隨機放入多個盒子問題，盒子數目與活躍節點的平均競爭窗口相關。當有多個球恰巧落入同一個盒子中時，表明相應時刻會有碰撞發生。針對結點重發次數有限的實際情況，將發送結點的狀態變化看作一個一維有限狀態的馬爾可夫過程，提出了一種基于虛發送周期和平均競爭窗口的計算802.11DCF容量的簡單方法。仿真結果驗證了該方法的合理性。To simplify the performance analysis of IEEE 802.11DCF in a saturated wireless LAN environment, a simple box-ball model is proposed. It regards the problem of packet transmission collisions as throwing some balls into several boxes randomly and independently. Balls are equal to the number of active nodes and boxes are related to the average contention window of each node. When two or more balls happen to fall into the same box, it means a collision would occur when the corresponding time slot arrives. In concern of limited retransmissions for every packet, the state transform of transmitting node is approximated as a finite-state one-dimension Markovian process. A simple method is finally proposed to evaluate the capacity of 802.11DCF based on the concepts of virtual transmission period and average contention window. Simulation results validate the analysis.