基于sigmoid函数的层内速率调节的分层组播

层内调节的多速率组播不从整体上重新划分层速率，而是固定每层的速率区间，选举层代表，并根据代表调整各层实际的发送速率。提出了基于sigmoid型函数的合成概率公式，描述了反馈者竞选成为代表的可能性。反馈者能否成为代表，取决于两个因素：反馈速率同当前层发送速率的相对差，和层内接收者的速率粗略分布情况。仿真实验表明，SFBLM可以满足层内大多数接收成员的速率需求，具有TCP友好性。

Sigmoid function-based layered multicast with intra-layer rate adjustment

Instead of re-layering and re-allocating sending rates, multi-rate multicast with intra-layer rate adjustment distributes layer's sending rate into fixed intervals and adjusts the actual layer's sending rate within its interval according to the selected delegate of the layer group. The synthesized probability formula based on sigmoid function was proposed for delegate selection. Two factors determine whether the current feedback receiver can be selected or not. One is the relative difference between feedback rate and current layer sending rate, the other is the approximate rate distribution of receivers within this layer group. Simulation results show that SFBLM can meet most of receivers' demand within a layer group, and it is TCP friendly.