Abstract: Problems such as high delay, high packet loss rate, low stability and reliability exist in current handoff scheme. To solve these problems, a dual-link communication mechanism and a dual-link selection were proposed, and the data transmission algorithm was presented in this paper to acquire accurate signal quality by smooth processing and control the handoff between two communication links at appropriate time by threshold of difference value and packet forwarding using dual-thread. The experimental results show that compared with the single link mechanism, no delayed pulse exists in dual-link mechanism, the packet loss rate is close to zero and the average throughput is increased by 20%. This mechanism can be applied to many environments owing high-speed mobile subnet such as metro, highway, etc.

Key words: dual-link, communication mechanism, handoff, delay, packet loss ratio

摘要： 针对现有切换机制和算法存在切换延迟较大、丢包率较高、不够稳定可靠等问题，提出一种双链路通信机制，给出一种双链路选择和数据传输算法，通过平滑处理获取精确信号质量，根据差值阈值控制两条通信链路在适当时机进行切换，并使用双线程进行数据转发。实验结果表明，与单链路机制相比，双链路机制不会出现延迟脉冲，丢包率接近于零，平均吞吐量提升了20%，可以应用到轨道交通、高速公路等具有高速移动子网的应用场合。

关键词: 双链路, 通信机制, 切换, 延迟, 丢包率