Neighbor discovery (ND) protocols are used for establishing a first contact between multiple wireless devices. The energy consumption and discovery latency of this procedure are determined by the parametrization of the protocol. In most existing protocols, reception and transmission are temporally coupled. Such schemes are referred to as \textit{slotted}, for which the problem of finding optimized parametrizations has been studied thoroughly in the literature. However, slotted approaches are not efficient in applications in which new devices join the network gradually and only the joining devices and a master node need to run the ND protocol simultaneously. For example, this is typically the case in IoT scenarios or Bluetooth Low Energy (BLE) piconets. Here, protocols in which packets are transmitted with periodic intervals (PI) can achieve significantly lower worst-case latencies than slotted ones. For this class of protocols, optimal parameter values remain unknown. To address this, we propose an optimization framework for PI-based BLE-like protocols, which translates any specified duty-cycle (and therefore energy budget) into a set of optimized parameter values. We show that the parametrizations resulting from one variant of our proposed scheme are optimal when one receiver discovers one transmitter, and no other parametrization or ND protocol - neither slotted nor slotless - can guarantee lower discovery latencies for a given duty-cycle in this scenario. Since the resulting protocol utilizes the channel more aggressively than other ND protocols, beacons will collide more frequently. Hence, due to collisions, the rate of successful discoveries gracefully decreases for larger numbers of devices discovering each other simultaneously. We also propose a scheme for configuring the BLE protocol (and not just BLE-\textit{like} protocols).

中文翻译：

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优化类似 BLE 的邻居发现

邻居发现 (ND) 协议用于在多个无线设备之间建立第一次联系。此过程的能耗和发现延迟由协议的参数化决定。在大多数现有协议中，接收和传输在时间上是耦合的。这种方案被称为\textit{slotted}，在文献中已经彻底研究了寻找优化参数化的问题。然而，在新设备逐渐加入网络并且只有加入设备和主节点需要同时运行ND协议的应用中，时隙方法效率不高。例如，在物联网场景或蓝牙低功耗 (BLE) 微微网中通常就是这种情况。这里，以周期性间隔 (PI) 传输数据包的协议可以实现比时隙协议低得多的最坏情况延迟。对于此类协议，最佳参数值仍然未知。为了解决这个问题，我们为基于 PI 的 BLE 类协议提出了一个优化框架，它将任何指定的占空比（以及因此的能量预算）转换为一组优化的参数值。我们表明，当一个接收器发现一个发射器时，由我们提出的方案的一种变体产生的参数化是最佳的，并且在这种情况下，没有其他参数化或 ND 协议（无论是时隙还是无时隙）都可以保证给定占空比的较低发现延迟。由于产生的协议比其他 ND 协议更积极地利用信道，信标将更频繁地碰撞。因此，由于冲突，对于同时发现彼此的大量设备，成功发现的比率会逐渐降低。我们还提出了一种配置 BLE 协议（而不仅仅是 BLE-\textit{like} 协议）的方案。