体域网是远程医疗和健康监护的重要环节，现有研究多采用电磁波传输。相比之下，人体软组织中超声波传播衰减小，产生的热量少，比电磁波传输距离远且致病风险低，利用超声波实现人体范围的通信和组网具有一定优势。现有的超声波宽带通信多采用超短脉冲减少多径交叠及其带来的干扰，结合直接序列扩频技术可以共享信道实现多点接入。但是，增加通信数量带来的干扰使目标通信链路接收节点的信噪比降低，采用固定帧长与码长无法保证通信可靠性。文中针对多点接入的场景，对节点的通信速率进行数学建模，研究竞争与合作两种场景下的自适应速率调整方法，利用凸优化理论的拉格朗日乘数法推导了帧长和码长的闭式解，在多点通信中动态改变帧长和码长实现速率调整。仿真结果表明，文中方法随着通信链路数及其干扰变化可实现自适应速率调整，其中，基于协商对策论的合作方案可以平衡不同节点的通信速率，获得更好的网络性能，基于速率最大的竞争方案有助于提高目标通信链路的有效通信速率，实际应用中需根据应用场景进行选择。

Body Area Network (BAN) is an important component for remote healthcare and health monitoring, and existing research often utilizes electromagnetic wave transmission for data transfer within the network. In contrast, ultrasound wave propagation in human soft tissue experiences less attenuation and generates less heat. Compared to electromagnetic wave transmission, ultrasound-based communication and networking within the human body have certain advantages, such as longer transmission distances and lower risks of inducing pathogenic effects. The existing ultrasonic wideband communication technology often uses ultra-short pulse to reduce path overlapping and the resulting interference. Besides, the multiple access through channel sharing can be realized by combining direct sequence spread spectrum. However, the interference caused by the increase of communication number reduces the received signal-to-noise ratio. Communication reliability can not be guaranteed with the fixed frame length and code length. In this paper, the adaptive rate adjustment of multiple access was modeled mathematically and the implementation methods based on competition and cooperation were studied. Then the close form solution was derived with the Lagrange multiplier method in convex optimization theory, with which the frame length and code length were dynamically changed to realize rate adjustment. Simulation results show that those methods can adapt to the changes of communication links and the resulting interference; the cooperative method based on bargaining game theory can obtain better network performance by balancing the communication rate of different access nodes; the competition scheme based on the maximum rate is helpful to improve the effective communication rate of the target communication link. In practical application, scheme should be selected according to the application scenario.