Optimizing BLE-Like Neighbor Discovery
Optimizing BLE-Like Neighbor Discovery
复制标题
优化类 BLE 邻居发现
DOI：
--
复制
发表时间：
2020
影响因子：
7.9
通讯作者：
S. Chakraborty
中科院分区：
文献类型：
--
作者：
Philipp H. Kindt;Swaminathan Narayanaswamy;M. Saur;S. Chakraborty
邻居发现 (ND) 协议用于在多个无线设备之间建立首次联系。该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，接收和传输是暂时耦合的。这种方案被称为槽式方案，文献中已经对寻找优化参数化的问题进行了深入研究。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，物联网场景或蓝牙低功耗 (BLE) 微微网中通常就是这种情况。在这里，解耦接收和传输的无时隙协议可以实现比时隙协议显着更低的最坏情况延迟。在本文中，我们研究了无时隙、类似 BLE 的协议，该协议使用周期间隔 (PI) 独立地调度接收和传输。对于此类协议，最佳参数值仍然未知。为了解决这个问题，我们提出了一个基于 PI 的协议的优化框架，它将任何指定的占空比（以及能源预算）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，我们提出的方案的一种变体产生的参数化是最佳的，并且没有其他参数化或ND协议（无论是时隙还是无时隙）都可以保证在这种情况下给定占空比的较低发现延迟。由于最终协议比其他 ND 协议更积极地利用信道，因此信标冲突会更频繁。因此，由于冲突，当大量设备同时发现彼此时，成功发现率会缓慢下降。我们还提出了一种配置 BLE 协议（而不仅仅是 BLE 类协议）的方案。尽管尚不清楚由此产生的参数化是否可以最大限度地降低 BLE 的延迟，但可以保证最坏情况下的延迟相当低。
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 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, slotless protocols that decouple reception and transmission can achieve significantly lower worst-case latencies than slotted ones. In this paper, we study slotless, BLE-like protocols, which schedule receptions and transmissions independently using periodic intervals (PI). For this class of protocols, optimal parameter values remain unknown. To address this, we propose an optimization framework for PI-based 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-like protocols). Though it is not clear whether the resulting parametrizations minimize the latencies of BLE, reasonably low worst-case latencies can be guaranteed.