We design two estimation schemes, Method I and Method II, for rapidly obtaining separate estimates of the number of active nodes of each traffic type in a heterogeneous machine-to-machine (M2M) network with T types of nodes (e.g., those that send emergency, periodic, normal type data etc.), where \(T\ge 2\) is an arbitrary integer. Method I is a simple scheme, and Method II is more sophisticated and outperforms Method I. Also, we design a medium access control (MAC) protocol that supports multi-channel operation for a heterogeneous M2M network with T types of nodes, operating as a secondary network using Cognitive Radio technology. In every time frame, our Cognitive MAC protocol uses the proposed estimation schemes to rapidly estimate the active node cardinality of each type, and uses these estimates to find the optimal contention probabilities to be used. We compute a closed form expression for the expected number of time slots required by Method I to execute, and a simple upper bound on it. Also, we analytically obtain expressions for the expected number of successful contentions per frame and the expected amount of energy consumed. Finally, we evaluate the performances of our proposed estimation schemes and Cognitive MAC protocol using simulations.

我们设计了两种估计方案，方法I和方法II，用于在具有T类节点（例如，那些发送消息的节点）的异构机器对机器（M2M）网络中快速获得每种流量类型的活动节点数的单独估计紧急，定期，常规类型数据等），其中\（T \ ge 2 \）是任意整数。方法I是一种简单的方案，方法II是更复杂的并且优于方法I。此外，我们设计了一种介质访问控制（MAC）协议，该协议支持具有T的异构M2M网络的多通道操作类型的节点，使用认知无线电技术作为辅助网络运行。在每个时间范围内，我们的认知MAC协议都使用提出的估计方案来快速估计每种类型的活动节点基数，并使用这些估计来找到要使用的最佳竞争概率。我们为方法I执行所需的预期时隙数以及其上的简单上限计算一个封闭形式的表达式。同样，我们通过分析获得每帧成功争用的预期数量和预期能耗的表达式。最后，我们使用仿真评估了我们提出的估计方案和认知MAC协议的性能。